Anaesthesia essentials: Articles

Abstract
The practice of anaesthetists relating to the administration of intraoperative oxygen has not been previously quantified in Australia and New Zealand. The optimal regimen of intraoperative oxygen administration to patients undergoing surgery under general anaesthesia is not known, and international recommendations for oxygen therapy are contradictory; the World Health Organization (WHO) recommend administering an intraoperative fraction of inspired oxygen of at least 0.8, while the World Federation of Societies of Anaesthesiologists, British Thoracic Society, and Thoracic Society of Australia and New Zealand recommend a more restrictive approach. We conducted a prospective observational study to describe the pattern of intraoperative oxygen administration among anaesthetists in Australia and New Zealand and, second, to determine the proportion of anaesthetists who administer intraoperative inspired oxygen in accordance with the WHO recommendations. We identified 150 anaesthetists from ten metropolitan hospitals in Australia and New Zealand and observed the patterns of intraoperative oxygen administration to American Society of Anesthesiologists physical status classification (ASA) 3 or 4 patients undergoing prolonged surgery under general anaesthesia. The median (interquartile range) intraoperative time-weighted mean fraction of inspired oxygen (FiO2) for all participants in the study was 0.47 (0.40-0.55). Three out of 150 anaesthetists (2%, 95% confidence interval 0.4 to 5.7) administered an average intraoperative FiO2 of at least 0.8. These findings indicate that most anaesthetists routinely administer an intermediate level of oxygen for ASA 3 or 4 adult patients undergoing prolonged surgery in Australia and New Zealand, rather than down-titrating inspired oxygen to a target pulse oximetry reading (SpO2) or administering liberal perioperative oxygen therapy in line with the current WHO recommendation.

Abstract
Introduction: Association between sugammadex and risk of postoperative nausea and vomiting remains unclear.

Evidence acquisition: We performed meta-analysis of randomized controlled trials with trial sequential analysis to compare sugammadex with neostigmine in adults receiving elective surgery under general anesthesia with postoperative extubation. Databases of MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from inception to April 15, 2022. Primary outcome was risk of postoperative nausea and vomiting after patients received sugammadex or neostigmine. Secondary outcomes were incidences of sugammadex-related complications.

Evidence synthesis: Meta-analysis of 40 trials with 5455 patients showed an overall lower risk of postoperative nausea and vomiting in the sugammadex group than in the neostigmine group (risk ratio: 0.85, 95% CI [0.76-0.94], heterogeneity I2=4%, P=0.002). Subgroup analyses demonstrated a lower risk of postoperative nausea and vomiting associated with sugammadex than with neostigmine: 1) in the postanesthesia care unit (risk ratio: 0.77, 95% CI [0.66-0.90], I2=8%, P=0.001) but not in wards; 2) under volatile anesthetics but not total intravenous anesthesia; 3) regardless of the administration of prophylactic antiemetics; and 4) when sugammadex was administered at 2 mg/kg but not 4 mg/kg. No major complications such as cardiac arrest or refractory bradycardia were noted and every patient achieved adequate neuromuscular recovery before extubation in all of the included trials. The overall quality of evidence was moderate.

Conclusions: Sugammadex was associated with a lower risk of postoperative nausea and vomiting compared with neostigmine immediately after surgery, especially for patients receiving volatile anesthetics regardless of the use of prophylactic antiemetics.

Abstract
This article addresses the issue of patient sleep during hospitalization, which the Society of Anesthesia and Sleep Medicine believes merits wider consideration by health authorities than it has received to date. Adequate sleep is fundamental to health and well-being, and insufficiencies in its duration, quality, or timing have adverse effects that are acutely evident. These include cardiovascular dysfunction, impaired ventilatory function, cognitive impairment, increased pain perception, psychomotor disturbance (including increased fall risk), psychological disturbance (including anxiety and depression), metabolic dysfunction (including increased insulin resistance and catabolic propensity), and immune dysfunction and proinflammatory effects (increasing infection risk and pain generation). All these changes negatively impact health status and are counterproductive to recovery from illness and operation. Hospitalization challenges sleep in a variety of ways. These challenges include environmental factors such as noise, bright light, and overnight awakenings for observations, interventions, and transfers; physiological factors such as pain, dyspnea, bowel or urinary dysfunction, or discomfort from therapeutic devices; psychological factors such as stress and anxiety; care-related factors including medications or medication withdrawal; and preexisting sleep disorders that may not be recognized or adequately managed. Many of these challenges appear readily addressable. The key to doing so is to give sleep greater priority, with attention directed at ensuring that patients' sleep needs are recognized and met, both within the hospital and beyond. Requirements include staff education, creation of protocols to enhance the prospect of sleep needs being addressed, and improvement in hospital design to mitigate environmental disturbances. Hospitals and health care providers have a duty to provide, to the greatest extent possible, appropriate preconditions for healing. Accumulating evidence suggests that these preconditions include adequate patient sleep duration and quality. The Society of Anesthesia and Sleep Medicine calls for systematic changes in the approach of hospital leadership and staff to this issue. Measures required include incorporation of optimization of patient sleep into the objectives of perioperative and general patient care guidelines. These steps should be complemented by further research into the impact of hospitalization on sleep, the effects of poor sleep on health outcomes after hospitalization, and assessment of interventions to improve it.

Perioperative arrhythmias are extremely common, usually transient and typically require no intervention. Persistent arrhythmias with associated haemodynamic instability may reflect an underlying pathological process. Indeed, the clinical scenario outlined of a patient with sepsis who develops rapid atrial fibrillation describes a situation that anaesthetists and intensivists frequently encounter. In some situations, the primary cause of the arrhythmia may be evident. However, in many cases the cause is multifactorial, relating to coexisting disease, acute physiological disturbance, medications or the surgical procedure itself (e.g. cardiac or thoracic surgery).

Abstract
Purpose: We aimed to describe the current literature concerning propofol misuse in medical professionals, specifically relating to the individual demographics of those misusing propofol and the outcomes of propofol misuse.

Methods: We conducted a retrospective scoping review of the literature using a modified PRISMA approach. We used MEDLINE, EMBASE, and PsycINFO databases to identify relevant studies based on search terms. Studies describing individual medical professionals misusing propofol were included.

Results: Twenty-four articles describing 88 individual cases of propofol misuse were included for data charting and analysis. Anesthesiologists and certified registered nurse anesthetists were most commonly identified. Death was a common method of identification of misuse, while rehabilitation and death were common final outcomes associated with propofol misuse.

Conclusions: Despite knowledge of the pharmacokinetic and pharmacodynamic properties of propofol by those misusing this medication, death was a common outcome reported in the literature. Data related to long-term outcomes including re-entry to clinical practice or success of rehabilitation were limited.

Abstract
Propfol-remifentanil-based total intravenous anaesthesia has dominated recent clinical practice due to its favourable pharmacokinetic profile. Interruption in remifentanil supply has presented an opportunity to diversify or even avoid the use of opioids and consider adjuncts to propofol-based total intravenous anaesthesia. Propofol, while a potent hypnotic, is not an effective analgesic. The administration of opioids, along with other adjuncts such as α-2 adrenoceptor agonists, magnesium, lidocaine, ketamine and nitrous oxide provide surgical anaesthesia and avoids large doses of propofol being required. We provide an overview of both target-control and manual infusion regimes for the alternative opioids: alfentanil, sufentanil and fentanyl. The optimal combination of hypnotic-opioid dose, titration sequence and anticipated additional postoperative analgesia required depend on the chosen combination. In addition, we include a brief discussion on the role of non-opioid adjuncts in total intravenous anaesthesia, suggested doses and expected reduction in propofol dose.

Tanya Rochelle Farrell and Britta S. von Ungern- Sternberg are both ANZCA fellows.

Abstract
Laryngotracheal injury is an increasingly common complication of intubation and mechanical ventilation, with an estimated 87% of intubated and ventilated patients developing a laryngotracheal injury often preventing their rehabilitation from acute illness. Laryngotracheal injuries encompass a diverse set of pathologies including inflammation and oedema in addition to vocal cord ulceration and paralysis, granuloma, stenosis, and scarring. The existing literature has identified several factors including intubation duration, endotracheal tube size, type and cuff pressures, and technical factors including the skill and experience of the endoscopist. Despite these associations, a key aspect in the sequelae of laryngotracheal injuries is due to reflux and is not clearly related to iatrogenic and mechanical factors.Laryngopharyngeal reflux is a type of reflux that contaminates the upper aerodigestive tract. The combination of patient positioning and continuous nasogastric tube feeding act to affect the upper aerodigestive tract with acidic and non-acidic refluxate that causes direct and indirect mucosal injury impeding healing.Despite laryngopharyngeal reflux being an established and recognised causative factor of upper aerodigestive tract inflammatory pathology and laryngotracheal injury, it is very understudied in critical care. Further, there is yet to be an agreed pathway to assess, manage and prevent laryngotracheal injury in intubated and ventilated patients. The incidence of laryngopharyngeal reflux in the intubated and mechanically ventilated patient in the intensive care unit is currently unknown. Prospective studies may allow us to understand further potential mechanisms of upper aerodigestive tract injury due to laryngopharyngeal reflux and herald the development of preventative and management strategies of laryngopharyngeal reflux-mediated upper aerodigestive tract injury in critically ill patients.

Abstract
Sedated patients have graded levels of consciousness and perceptual connection with the outside world. Disconnection is associated with widespread changes in the electroencephalogram, whereas full unconsciousness is linked with decreased activity specifically in the deep midline regions of the brain. These findings can be interpreted within the predictive coding model of consciousness as differences in model generation vs discrepancy detection. Anaesthetists should be cognisant that apparently unresponsive patients might still have some ongoing partially disconnected consciousness activity.

Abstract
Anaesthetic choice for large joint surgery can impact postoperative outcomes, including mortality. The extent to which the impact of anaesthetic choice on postoperative mortality varies within patient populations and the extent to which anaesthetic choice is changing over time remain under-explored both internationally and in the diverse New Zealand context. In a national study of 199,211 hip and knee replacement procedures conducted between 2005 and 2017, we compared postoperative mortality among those receiving general, regional or general plus regional anaesthesia. Focusing on unilateral (n=86,467) and partial (n=13,889) hip replacements, we assessed whether some groups within the population are more likely to receive general, regional or general plus regional anaesthesia than others, and whether mortality risk varies depending on anaesthetic choice. We also examined temporal changes in anaesthetic choice over time. Those receiving regional alone or general plus regional for unilateral hip replacement appeared at increased risk of 30-day mortality compared to general anaesthesia alone, even after adjusting for differences in terms of age, ethnicity, deprivation, rurality, comorbidity, American Society of Anesthesiologists physical status score and admission type (e.g. general plus regional: adjusted hazard ratio (adj. HR)=1.94, 95% confidence intervals (CI) 1.32 to 2.84). By contrast, we observed lower 30-day mortality among those receiving regional anaesthesia alone compared to general alone for partial hip replacement (adj. HR=0.86, 95% CI 0.75 to 0.97). The latter observation contrasts with declining temporal trends in the use of regional anaesthesia alone for partial hip replacement procedures. However, we recognise that postoperative mortality is one perioperative factor that drives anaesthetic choice.

Abstract
The Australian and New Zealand College of Anaesthetists (ANZCA) recently reviewed and updated the guideline on equipment to manage a difficult airway. An ANZCA-established document development group, which included representatives from the Australasian College for Emergency Medicine and the College of Intensive Care Medicine of Australia and New Zealand, performed the review, which is based on expert consensus, an extensive literature review, and bi-nationwide consultation. The guideline (PG56(A) 2021, https://www.anzca.edu.au/getattachment/02fe1a4c-14f0-4ad1-8337-c281d26bfa17/PS56-Guideline-on-equipment-to-manage-difficult-airways) is accompanied by a detailed background paper (PG56(A)BP 2021, https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PG56(A)BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper), from which the current recommendations are reproduced on behalf of, and with the permission of, ANZCA. The updated 2021 guideline replaces the 2012 version and aims to provide an updated, objective, informed, transparent, and evidence-based review of equipment to manage difficult airways.

No abstract available.

Abstract
Background and aims: Patient satisfaction is an important measure of quality of health care. Its assessment leads to a balanced evaluation of the structure, process and outcome of service at an institution. The aim of our study was to assess patient satisfaction with perioperative anaesthesia services provided in our institution and identify factors leading to dissatisfaction which could be preventable or addressed to improve patient care and experience.

Material and methods: A convenient sample size of 200 patients was accrued after written informed consent. A questionnaire to suit local needs of institute was developed, validated and a language appropriate questionnaire was administered by a trained research nurse 24-48 hours post anaesthesia to accrued patients. Data was summarised in percentages and satisfaction scores were compared across demographic variables using Chi square test.

Results: A total of 96% (192/200) patients were satisfied with the overall interaction with the anaesthetists in the perioperative period; with 99% (198/200) patients being satisfied with acute pain services provided, postoperatively. As regards to recovery room, 96.5% (193/200) patients were satisfied with the services provided. Satisfaction scores of the pre-anaesthetic clinic (PAC), pain team and anaesthesia services compared across demographic variables - age, gender and education qualifications were found to be statistically non-significant.

Conclusion: High rate of patients were satisfied with perioperative anaesthesia care services at our institute. Good and effective preoperative communication with the patient, effective management of postoperative pain and complications significantly contributed towards overall high patient satisfaction.

Abstract
Background: In colorectal cancer, surgical resection is fundamental for curative treatment. Epidural analgesia mitigates the perioperative physiologic stress response caused by surgery, and reduction in perioperative stress may reduce postoperative complications. Nevertheless, epidural analgesia also causes hypotension and lower limb motor weakness that can impair postoperative recovery. Here, we aimed to assess the association between epidural analgesia and postoperative complications after colorectal cancer surgery.

Methods: We identified patients undergoing colorectal cancer surgery 2008-2018 in Denmark in the Danish Colorectal Cancer Group Database and obtained anaesthesia data from the Danish Anaesthesia Database. The Danish National Prescription Registry was used to obtain data on prescriptions filled preoperatively reflecting current comorbidities. Databases were linked using the Danish Central Person Registry number and the operation day. Patients were classified according to preoperative insertion of an epidural catheter for analgesia. Confounders were adjusted by propensity score matching. Logistic regression was used to compute effect estimates of epidural analgesia on postoperative complications.

Results: We identified 19932 individuals undergoing colorectal cancer surgery with available anaesthesia data. Propensity score matching yielded 5691 individuals in each group with balanced preoperative covariates. In the epidural analgesia group 1400 (24.6%) experienced complications compared with 1453 (25.5%) without epidural analgesia. We found no statistically significant association between epidural use and postoperative complications (OR 0.95, 95% CI 0.87-1.04).

Conclusion: In total, in this observational study based on Danish registries, we found no association between epidural analgesia and postoperative complications after colorectal cancer surgery.

Abstract
Background: There is no consensus about the type of instrument with which to assess postoperative recovery or the time points when assessments are most appropriate. It is also unclear whether instruments measure the four dimensions of postoperative recovery, that is physical, psychological, social, and habitual recovery. This scoping review had three objectives: (1) to identify and describe instruments used in clinical trials to assess postoperative recovery; (2) to determine how, when, and the number of times postoperative recovery was measured; and (3) to explore whether the four dimensions of postoperative recovery are represented in the identified instruments.

Methods: A literature search was conducted in CINAHL, MEDLINE, and Web of Science. The search terms were related to three search strands: postoperative recovery, instrument, and clinical trials. The limits were English language and publication January 2010 to November 2021. In total, 5015 studies were identified.

Results: A total of 198 studies were included in the results. We identified 20 instruments measuring postoperative recovery. Different versions of Quality of Recovery represented 81.8% of the included instruments. Postoperative recovery was often assessed at one time point (47.2%) and most often on postoperative day 1 (81.5%). Thirteen instruments had items covering all four dimensions of postoperative recovery.

Conclusions: Assessing recovery is important to evaluate and improve perioperative care. We emphasise the importance of choosing the right instrument for the concept studied and, if postoperative recovery is of interest, of assessing more than once. Ideally, instruments should include all four dimensions to cover the whole recovery process.

bstract
Background: The wakeful brain can easily access and coordinate a large repertoire of different states-dynamics suggestive of "criticality." Anesthesia causes loss of criticality at the level of electroencephalogram waveforms, but the criticality of brain network connectivity is less well studied. The authors hypothesized that propofol anesthesia is associated with abrupt and divergent changes in brain network connectivity for different frequencies and time scales-characteristic of a phase transition, a signature of loss of criticality.

Methods: As part of a previously reported study, 16 volunteers were given propofol in slowly increasing brain concentrations, and their behavioral responsiveness was assessed. The network dynamics from 31-channel electroencephalogram data were calculated from 1 to 20 Hz using four phase and envelope amplitude-based functional connectivity metrics that covered a wide range of time scales from milliseconds to minutes. The authors calculated network global efficiency, clustering coefficient, and statistical complexity (using the Jensen-Shannon divergence) for each functional connectivity metric and compared their findings with those from an in silico Kuramoto network model.

Results: The transition to anesthesia was associated with critical slowing and then abrupt profound decreases in global network efficiency of 2 Hz power envelope metrics (from mean ± SD of 0.64 ± 0.15 to 0.29 ± 0.28 absolute value, P < 0.001, for medium; and from 0.47 ± 0.13 to 0.24 ± 0.21, P < 0.001, for long time scales) but with an increase in global network efficiency for 10 Hz weighted phase lag index (from 0.30 ± 0.20 to 0.72 ± 0.06, P < 0.001). Network complexity decreased for both the 10 Hz hypersynchronous (0.44 ± 0.13 to 0.23 ± 0.08, P < 0.001), and the 2 Hz asynchronous (0.73 ± 0.08 to 0.40 ± 0.13, P < 0.001) network states. These patterns of network coupling were consistent with those of the Kuramoto model of an order-disorder phase transition.

Conclusions: Around loss of behavioral responsiveness, a small increase in propofol concentrations caused a collapse of long time scale power envelope connectivity and an increase in 10 Hz phase-based connectivity-suggestive of a brain network phase transition.

Abstract
In this article, I present a firsthand account as an anaesthetist with substance use disorder who has been through rehabilitation and returned to clinical anaesthesia, followed by an overview of substance use disorder in anaesthesia. Substance use disorder is prevalent within the anaesthesia community and can result in tragic consequences, including death in many cases. The incidence is around one to two per 1000 anaesthetist years and this appears to be rising, perhaps mirroring the population-wide increase in substance use disorder as a result of the opioid epidemic. Recognising substance use disorder in a colleague and intervening to try and help them and protect patients can be immensely challenging. Carrying out a successful intervention requires careful planning and coordination in order to protect the affected individual, their colleagues and patients. Returning to clinical anaesthesia following a diagnosis of substance use disorder is also contentious, with the high abstinence rate (relative to the wider substance use disorder population) having to be balanced against the risk of death following relapse. Any return to practice must be well planned and supported, and include appropriate toxicology screening. With such measures, rehabilitation and a return to clinical anaesthesia is possible in certain cases. For the affected individual regaining, then maintaining, their professional identity can be a powerful motivator to remain abstinent. Drug diversion and substance use disorder in anaesthesia is unlikely ever to be fully preventable, but strategies such as biometric dispensing, analysis of unused drugs, random toxicology and ongoing education may help to keep it to a minimum.

Abstract
Background: Women are less likely than men to receive some emergency treatments. This study examines whether the effect of tranexamic acid (TXA) on mortality in trauma patients varies by sex and whether the receipt of TXA by trauma patients varies by sex.

Methods: First, we conducted a sex-disaggregated analysis of data from the Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH)-2 and CRASH-3 trials. We used interaction tests to determine whether the treatment effect varied by sex. Second, we examined data from the Trauma and Audit Research Network (TARN) to explore sex differences in the receipt of TXA. We used logistic regression models to estimate the odds ratio for receipt of TXA in females compared with males. Results are reported as n (%), risk ratios (RR), and odds ratios (OR) with 95% confidence intervals.

Results: Overall, 20 211 polytrauma patients (CRASH-2) and 12 737 patients with traumatic brain injuries (CRASH-3) were included in our analysis. TXA reduced the risk of death in females (RR=0.69 [0.52-0.91]) and in males (RR=0.80 [0.71-0.90]) with no significant heterogeneity by sex (P=0.34). We examined TARN data for 216 364 patients aged ≥16 yr with an Injury Severity Score ≥9 with 98 879 (46%) females and 117 485 (54%) males. TXA was received by 7198 (7.3% [7.1-7.4%]) of the females and 19 697 (16.8% [16.6-17.0%]) of the males (OR=0.39 [0.38-0.40]). The sex difference in the receipt of TXA increased with increasing age.

Conclusions: Administration of TXA to patients with bleeding trauma reduces mortality to a similar extent in women and men, but women are substantially less likely to be treated with TXA.

Abstract
Robot-assisted laparoscopic prostatectomy requires a pneumoperitoneum combined with steep Trendelenburg positioning, and these conditions can be associated with impairment of cerebral autoregulation. The objective of this study was to determine if choice of anaesthetic agent affects the preservation of cerebral autoregulation during robot-assisted laparoscopic prostatectomy. We randomly assigned 30 patients to maintenance of general anaesthesia with either propofol or sevoflurane. Cerebral autoregulation was tested by administration of intravenous phenylephrine to increase mean arterial pressure from approximately 80 mmHg to 100 mmHg while assessing cerebral blood flow using transcranial Doppler ultrasonography. Autoregulation was first tested in the supine position and then approximately once every hour after Trendelenburg positioning. The main outcome measure was the result of the final autoregulation test prior to completion of surgery. At that time, we found cerebral autoregulation to be significantly impaired in six of the 15 patients receiving sevoflurane and none of the 15 patients receiving propofol (P = 0.02). However, it should be noted that some patients in the propofol group had impaired autoregulation on earlier tests. In conclusion, we found that autoregulation during robot-assisted laparoscopic prostatectomy is less likely to be impaired with propofol compared to sevoflurane anaesthesia, particularly towards the end of the surgery.

Abstract
Background: Monitoring children's recovery postoperatively is important for routine care, research, and quality improvement. Although telephone follow-up is common, it is also time-consuming and intrusive for families. Using SMS messaging to communicate with families regarding their child's recovery has the potential to address these concerns. While a previous survey at our institution indicated that parents were willing to communicate with the hospital by SMS, data on response rates for SMS-based postoperative data collection is limited, particularly in pediatric populations.

Aims: We conducted a feasibility study with 50 completed pain profiles obtained from patients at Perth Children's Hospital to examine response rates.

Methods: We collected and classified daily average pain (0-10 parent proxy score) on each day after tonsillectomy until pain-free for two consecutive days.

Results: We enrolled 62 participants and recorded 50 (81%) completed pain profiles, with 711 (97.9%) of 726 requests for a pain score receiving a response. Two families (3%) opted out of the trial, and 10 (16%) were lost to follow-up. Responses received were classified automatically in 92% of cases. No negative feedback was received, with a median (range) satisfaction score of 5 on a 5-point Likert scale (1 = very unhappy, 5 = very happy).

Conclusions: This methodology is likely to generalize well to other simple clinical questions and produce good response rates in further similar studies. We expect SMS messaging to permit expanded longitudinal data collection and broader investigation into patient recovery than previously feasible using telephone follow-up at our institution.

Purpose: This study aims to compare the efficacy of ultrasound-guided interscalene block (US-ISB) with that of intravenous analgesia and sedation (IVAS) in reducing first shoulder dislocation.

Material and methods: A prospective study was performed in 66 patients with first anterior shoulder dislocation in emergency department. The patients were divided into a US-ISB (n = 32) group and an IVAS (IVAS n = 34) group. The procedure time (anesthesia, reduction, and hospital times), pain score (before, during, and after reduction), reduction attempts, complications, and patient satisfaction were recorded and compared between the two groups.

Results: The anesthesia time (P < 0.01) and reduction time (P < 0.01) were shorter and the hospital time (P < 0.01) was longer in the IVAS group than in the US-ISB group. No significant differences in preoperative (P = 0.18) and postoperative (P = 0.27) pain scores were found between the two groups, but the intraoperative score of the US-ISB group was significantly higher than that of the IVAS group. More reduction attempts (P < 0.01) were recorded in the US-ISB group than that in the IVAS group. Complications (P < 0.01) such as nausea, vomiting, headache, and hypoxia occurred more frequently in the IVAS group than in the US-ISB group. No significant difference in patient satisfaction was observed between two groups (P = 0.96).

Conclusion: Compared with IVAS group, US-ISB group reduces the time to discharge and achieves lesser complication. The pain score and reduction attempt are lower in the IVAS group than in the US-ISB group.

As the field of anesthesiology evolves and grows, so does the important role women play in its ongoing success and development. The ASA Monitor had the privilege of speaking with three women whose leadership and expertise have had – and continue to have – a positive impact on anaesthesiology and medicine as a whole.

Massive transfusions guided by massive transfusion protocols are commonly used to manage critical bleeding, when the patient is at significant risk of morbidity and mortality, and multiple timely decisions must be made by clinicians. Clinical decision support systems are increasingly used to provide patient-specific recommendations by comparing patient information to a knowledge base, and have been shown to improve patient outcomes. To investigate current massive transfusion practice and the experiences and attitudes of anaesthetists towards massive transfusion and clinical decision support systems, we anonymously surveyed 1000 anaesthetists and anaesthesia trainees across Australia and New Zealand. A total of 228 surveys (23.6%) were successfully completed and 227 were analysed for a 23.3% response rate. Most respondents were involved in massive transfusions infrequently (88.1% managed five or fewer massive transfusion protocols per year) and worked at hospitals which have massive transfusion protocols (89.4%). Massive transfusion management was predominantly limited by timely access to point-of-care coagulation assessment and by competition with other tasks, with trainees reporting more significant limitations compared to specialists. The majority of respondents reported that they were likely, or very likely, both to use (73.1%) and to trust (85%) a clinical decision support system for massive transfusions, with no significant difference between anaesthesia trainees and specialists (P = 0.375 and P = 0.73, respectively). While the response rate to our survey was poor, there was still a wide range of massive transfusion experience among respondents, with multiple subjective factors identified limiting massive transfusion practice. We identified several potential design features and barriers to implementation to assist with the future development of a clinical decision support system for massive transfusion, and overall wide support for a clinical decision support system for massive transfusion among respondents.

We note with interest the results of the survey by Sanderson et al.1 The survey demonstrated majority support amongst clinicians for point-of-care (POC) viscoelastic haemostatic assay (VHA) results to be displayed with transfusion recommendations and for a computerised clinical decision support (CDS) system to guide massive transfusion (MT) management. We write to describe our experience in developing a smartphone CDS tool for rotational thromboelastometry (ROTEMVR; TEM International GmbH, Munich, Germany) interpretation at our institution to improve complex algorithm interpretation and to provide decision support during MT.

Abstract
In Australia, 2.7 million surgical procedures are performed annually. Historically, a lack of perioperative data standardisation and infrastructure has limited pooling of routinely collected data across institutions. We surveyed Australian and New Zealand College of Anaesthetists (ANZCA) Clinical Trials Network hospitals to investigate current and potential uses of perioperative electronic medical record data for research and quality assurance.A targeted survey was sent to 131 ANZCA Clinical Trials Network-affiliated hospitals in Australia. The primary aim was to map current electronic data collection methods and data utilisation in six domains of the perioperative pathway.The survey response rate was 32%. Electronic data recording in the six domains ranged from 19% to 85%. Where electronic data exist, the ability of anaesthesiology departments to export them for analysis ranged from 27% to 100%. The proportion of departments with access to data exports that are regularly exporting the data for quality assurance or research ranged from 13% to 58%.The existence of a perioperative electronic medical record does not automatically lead to the data being used to measure and improve clinical outcomes. The first barrier is clinician access to data exports. Even when this barrier is overcome, a large gap remains between the proportion of departments able to access data exports and those using the data regularly to inform and improve clinical practice. We believe this gap can be addressed by establishing a national perioperative outcomes registry to lead high-quality multicentre registry research and quality assurance in Australia.

Abstract
This cross-sectional overview of the second 4000 incidents reported to webAIRS has findings that are very similar to the previous overview of the first 4000 incidents. The distribution of patient age, body mass index and American Society of Anesthesiologists physical status was similar, as was anaesthetist gender, grade, location and time of day of incidents. About 35% of incidents occurred during non-elective procedures (vs. 33% in the first 4000 incidents). The proportion of incidents in the various main categories was also similar, with respiratory/airway being most common, followed by cardiovascular, medication-related and medical device or equipment-related incidents. Together these categories made up about 78% of all incidents in both overviews. The immediate outcome was comparable with reports of harm in about a quarter of incidents and a similar rate of deaths (4.7% vs. 4.2%). However, the proportion of patients who had received total intravenous anaesthesia was higher (17.6% vs. 7.7%) and the proportion of patients who received combined intravenous and inhalational anaesthesia was lower (52.3% vs. 58.4%), as was the proportion receiving local anaesthesia alone (1.6% vs. 6.7%). There was a small increase in the number of incidents resulting in unplanned admission to a high dependency or intensive care unit (18.1% vs. 13.5%). It is not clear whether these differences represent trends or random observations. About 48% of incidents were considered preventable by the reporters (vs. 52% in the first 4000). These findings support continued emphasis on human and system factors to promote and improve patient safety in anaesthesia care.

Abstract
Background: Anaesthesia is a stressful medical specialty. The reaction to stress is constituted by behavioural, psychological and physiological components. Chronic physiological stress can have negative consequences for health.

Objectives: First, we hypothesised that chronic physiological stress is higher for both beginning and late-career consultant anaesthesiologists. Second, we hypothesised that individuals high in emotional intelligence endure lower physiological stress.

Design: Cross-sectional biomarker and survey study.

Setting: Participants were recruited during the May 2019 annual meeting of the Dutch Anaesthesia Society.

Participants: Of the 1348 colleagues who attended the meeting, 184 (70 male/114 female) participated in the study. Of the study participants, 123 (67%) were consultant anaesthesiologists (52 male/71 female) and 61 (33%) were resident anaesthesiologists (18 male/43 female). Exclusion criteria were endocrine disorders and not having enough hair. Also, experience of a recent major life event led to exclusion from analysis of our hypotheses.

Main outcome measures: Chronic physiological stress was measured by hair cortisol concentration. Emotional intelligence was assessed using a validated Dutch version of the Trait Emotional Intelligence Questionnaire. As secondary measures, psychological sources of stress were assessed using validated Dutch versions of the home-work interference (SWING) and the effort-reward imbalance questionnaires.

Results: In support of Hypothesis 1, hair cortisol concentration was highest among early and late-career consultant anaesthesiologists (quadratic effect: b = 45.5, SE = 16.1, t = 2.8, P = 0.006, R2 = 0.14). This nonlinear pattern was not mirrored by self-reported sources of psychological stress. Our results did not support Hypothesis 2; we found no evidence for a relationship between emotional intelligence and physiological stress.

Conclusion: In the early and later phases of an anaesthesiologist's career, physiological chronic stress is higher than in the middle of the career. However, this physiological response could not be explained from known sources of psychological stress. We discuss these findings against the background of key differences between physiological and psychological stress.

Purpose: We have developed an automated anesthesia control system that uses biological information to provide closed-loop control of drug administration for total intravenous anesthesia with propofol, remifentanil, and rocuronium. In this study, we investigated whether the control of sedatives, analgesics, and muscle relaxants delivered by this system is non-inferior to that delivered by anesthesiologists.

Methods: During anesthesia management by our automated administration control system and by anesthesiologists, the concentration of each drug at the site of effect (calculated from drug administration history) and biometric information (bispectral index, blood pressure, pulse rate, and single contraction ratio %T1) were tabulated during the period from the start to end of surgery. The primary efficacy endpoint was the ratio of adequate anesthesia time, in which all three factors of sedation, analgesia, and muscle relaxation were maintained within the target range, to the period from the start to end of surgery under total intravenous anesthesia.

Results: Percentage of time under appropriate anesthesia was 73.24 ± 17.24 in the automatic group (n = 28) and 59.94 ± 29.06 in the manual group (n = 28). The lower limit of the 97.5% one-sided confidence interval for the difference between the two group means was 0.51%, indicating the non-inferiority of the automatic group to the manual group (p = 0.002). The incidence of adverse events did not differ significantly between the groups.

Conclusion: The clinical use of our automated anesthesia control system should allow for the maintenance of adequate anesthesia by adjusting the doses of intravenous anesthetics in the same way as anesthesiologists do.

Perioperative anaphylaxis is a severe adverse event during anesthesia that requires prompt diagnosis and treatment by physicians, including anesthesiologists. Muscle relaxants and antibiotics are the most common drugs that cause perioperative anaphylaxis in Japan, as in many countries. In addition, sugammadex appears to be a primary causative agent. Obtaining previous anesthesia records is necessary in a patient with a history of allergic reactions during anesthesia, whenever possible, to avoid recurrence of anaphylaxis. Although medical staff are likely to notice abnormal vital signs because of complete monitoring during anesthesia, surgical drapes make it difficult to notice the appearance of skin symptoms. Even if there are no skin symptoms, anaphylaxis should be suspected, especially when hypotension resistant to inotropes and vasopressors persists. For improving the diagnostic accuracy of anaphylaxis, it is helpful to collect blood samples to measure histamine/tryptase concentrations immediately after the events and at baseline. The first-line treatment for anaphylaxis is adrenaline. In the perioperative setting, adrenaline should be administered through the intravenous route, which has a faster effect onset and is secured in most cases. Adrenaline can cause serious complications including severe arrhythmias if the appropriate dose is not selected according to the severity of symptoms. The anesthesiologist should identify the causative agent after adverse events. The gold standard for identifying the causative agent is the skin test, but in vitro tests including specific IgE antibody measurements and basophil activation tests are also beneficial. The Working Group of the Japanese Society of Anesthesiologists has developed this practical guide to help appropriate prevention, early diagnosis and treatment, and postoperative diagnosis of anaphylaxis during anesthesia.Grade of recommendations and levels of evidence Anaphylaxis is a relatively rare condition with few controlled trials, and thus a so-called evidence-based scrutiny is difficult. Therefore, rather than showing evidence levels and indicating the level of recommendation, this practical guideline only describes the results of research available to date. The JSA will continue to investigate anaphylaxis during anesthesia, and the results may lead to an amendment of this practical guideline.

During recent years a lot of interest has been focused on blood pressure in the context of pediatric anesthesia, trying to define what is normal in relation to age and what numeric values that should be regarded as hypotension, needing active intervention. However, blood pressure is mainly measured as a proxy for flow, i.e., cardiac output. Thus, just focusing on specific blood pressure numbers may not necessarily be very useful or appropriate. The aim of this educational review is to put the issue of intraoperative blood pressure in the context of pediatric anesthesia in further perspective.

Abstract
There are no published data on the age of retirement of anaesthetists in Australia and New Zealand. We surveyed 622 retired Fellows of the Australian and New Zealand College of Anaesthetists to determine their ages of complete retirement from clinical practice, demographics, and whether they had retired at the age they had intended to retire. We also aimed to explore factors affecting the decision to retire, the practice of 'winding down', common post-retirement activities, and the arrangement of personal and professional affairs. Responses were received from 371 specialists (response rate 60%). The mean (standard deviation) age of retirement was 65.2 (6.9) years. The mean (standard deviation) retirement ages ranged from 62.0 (7.1) years (those who retired earlier than planned) to 68.0 (4.3) years (those who retired later than they had intended). The mean (standard deviation) age of retirement of the male respondents was 66.0 (6.5) years, and for female respondents was 62.7 (7.7) years. Two hundred and thirty-three respondents (63%) reported winding down their practice prior to retirement, and 360 (97%) had made a will. Poor health and loss of confidence were the two most common factors in the retirement decisions of those who retired earlier than they had planned. Our results may assist current practitioners plan for retirement, and suggest strategies to help health services, departments and private groups accommodate individuals in winding down their practice.

Abstract
A study in this edition of the Journal has added to data showing that failures in communication in the operating room contribute to patient harm. These data support the view that multidisciplinary teamwork and communication training should be part of the continuous professional development of all members of the perioperative team. Achieving change will require efforts to win the hearts and minds of all concerned, but these data also support an expectation that engagement in initiatives and techniques to enhance communication and teamwork should not be optional.

The first case of what eventually became known as malignant hyperthermia (MH) was reported by Denborough et al. in 1962.1 Since then, great progress has been made in the field, from identifying the majority of genes predisposing patients to an MH reaction to gaining mechanistic insight into the calcium dyshomeostasis observed in cells from patients with MH (as well as in MH animal models). One recurrent observation has been an enhanced cytosolic intracellular calcium which has been found both in human MH susceptible (MHS) samples and in mouse models of MH.2–6 A question that remains is how skeletal muscles appear to function normally in the absence of a triggering anesthetic, despite
persistent elevations in cytosolic intracellular calcium.

Abstract
Emergence agitation (EA) is a self-limited state of psychomotor excitement during awakening from general anesthesia. EA is confined to the emergence period as consciousness is restored, which sharply distinguishes it from other postoperative delirium states. Sporadic episodes of EA may become violent with the potential for harm to both patients and caregivers, but the long-term consequences of such events are not fully understood. Current literature on EA in adults is limited to small-scale studies with inconsistent nomenclature, variable time periods that define emergence, a host of different surgical populations, and conflicting diagnostic criteria. Therefore, true incidence rates and risk factors are unknown. In adult noncardiac surgery, the incidence of EA is approximately 19%. Limited data suggest that young adults undergoing otolaryngology operations with volatile anesthetic maintenance may be at the highest risk for EA. Currently suggested EA mechanisms are theoretical but might reflect underblunted sympathetic activation in response to various internal (eg, flashbacks or anxiety) or external (eg, surgical pain) stimuli as consciousness returns. Supplemental dexmedetomidine and ketamine may be utilized for EA prevention. Compared to the civilian population, military veterans may be more vulnerable to EA due to high rates of posttraumatic stress disorder (PTSD) manifesting as violent flashbacks; however, confirmatory data are limited. Nonetheless, expert military medical providers suggest that use of patient-centered rapport tactics, PTSD trigger identification and avoidance, and grounding measures may alleviate hyperactive emergence phenomena. Future research is needed to better characterize EA in veterans and validate prophylactic measures to optimize care for these patients. This narrative review provides readers with an important framework to distinguish EA from delirium. Furthermore, we summarize current knowledge of EA risk factors, mechanisms, and adult management strategies and specifically revisit them in the context of veteran perioperative health. The anesthesiology care team is ideally positioned to further explore EA and develop effective prevention and treatment protocols.

Abstract
The emergence from anesthesia is the stage of general anesthesia featuring the patient's progression from the unconsciousness status to wakefulness and restoration of consciousness. This complex process has precise neurobiology which differs from that of induction. Despite the medications commonly used in anesthesia allow recovery in a few minutes, a delay in waking up from anesthesia, called delayed emergence, may occur. This phenomenon is associated with delays in the operating room, and an overall increase in costs. Together with the emergence delirium, the phenomenon represents a manifestation of inadequate emergence. Nevertheless, in delayed emergence, the transition from unconsciousness to complete wakefulness usually occurs along a normal trajectory, although slowed down. On the other hand, this awakening trajectory could proceed abnormally, possibly culminating in the manifestation of emergence delirium. Clinically, delayed emergence often represents a challenge for clinicians who must make an accurate diagnosis of the underlying cause to quickly establish appropriate therapy. This paper aimed at presenting an update on the phenomenon, analyzing its causes. Diagnostic and therapeutic strategies are addressed. Finally, therapeutic perspectives on the "active awakening" are reported.

Methods: In this pragmatic, international, noninferiority trial, we randomly assigned 8880 adult patients who were undergoing nonurgent, noncardiac surgery of at least 2 hours' duration, with a skin incision length longer than 5 cm and a postoperative overnight hospital stay, to receive 8 mg of intravenous dexamethasone or matching placebo while under anesthesia. Randomization was stratified according to diabetes status and trial center. The primary outcome was surgical-site infection within 30 days after surgery. The prespecified noninferiority margin was 2.0 percentage points.

Results: A total of 8725 participants were included in the modified intention-to-treat population (4372 in the dexamethasone group and 4353 in the placebo group), of whom 13.2% (576 in the dexamethasone group and 572 in the placebo group) had diabetes mellitus. Of the 8678 patients included in the primary analysis, surgical-site infection occurred in 8.1% (354 of 4350 patients) assigned to dexamethasone and in 9.1% (394 of 4328) assigned to placebo (risk difference adjusted for diabetes status, -0.9 percentage points; 95.6% confidence interval [CI], -2.1 to 0.3; P<0.001 for noninferiority). The results for superficial, deep, and organ-space surgical-site infections and in patients with diabetes were similar to those of the primary analysis. Postoperative nausea and vomiting in the first 24 hours after surgery occurred in 42.2% of patients in the dexamethasone group and in 53.9% in the placebo group (risk ratio, 0.78; 95% CI, 0.75 to 0.82). Hyperglycemic events in patients without diabetes occurred in 22 of 3787 (0.6%) in the dexamethasone group and in 6 of 3776 (0.2%) in the placebo group.

Conclusions: Dexamethasone was noninferior to placebo with respect to the incidence of surgical-site infection within 30 days after nonurgent, noncardiac surgery. (Funded by the Australian National Health and Medical Research Council and others; PADDI Australian New Zealand Clinical Trials Registry number, ACTRN12614001226695.).

Methods/analysis: This is a pragmatic, multicentre, randomised, controlled, non-inferiority trial. A total of 8880 patients undergoing elective major surgery will be enrolled. Participants will be randomly allocated to receive either dexamethasone 8 mg or placebo intravenously following the induction of anaesthesia in a 1:1 ratio, stratified by centre and diabetes status. Patient enrolment into the trial is ongoing. The primary outcome is surgical site infection at 30 days following surgery, defined according to the Centre for Disease Control criteria.

Ethics/dissemination: The PADDI trial has been approved by the ethics committees of over 45 participating sites in Australia, New Zealand, Hong Kong, South Africa and the Netherlands. The trial has been endorsed by the Australia and New Zealand College of Anaesthetists Clinical Trials Network and the Australian Society for Infectious Diseases Clinical Research Network. Participant recruitment began in March 2016 and is expected to be complete in mid-2019. Publication of the results of the PADDI trial is anticipated to occur in early 2020.

Trial registration number: ACTRN12614001226695.

Keywords: Dexamethasone; Diabetes; Postoperative Nausea and Vomiting; Surgical Wound Infection; glucocorticoid.

Abstract
Background: The COVID-19 pandemic has greatly affected access to elective surgery, largely because of concerns for patients and healthcare workers. A return to normal surgery workflow depends on the prevalence and transmission of coronavirus in elective surgical patients. The aim of this study was to determine the prevalence of active SARS-coronavirus-2 infection during a second wave among patients admitted to hospital for elective surgery in Victoria.

Methods: Prospective cohort study across eight hospitals in Victoria during July-August 2020 was conducted enrolling adults and children admitted to hospital for elective surgery or interventional procedure requiring general anaesthesia. Study outcomes included a positive polymerase chain reaction (PCR) test for SARS-CoV-2 in the preoperative period (primary outcome), and for those with a negative test preoperatively, the incidence of a positive PCR test for SARS-CoV-2 in the post-operative period.

Results: We enrolled 4965 elective adult and paediatric surgical patients from 15 July to 31 August 2020. Four patients screened negative on questionnaire but had a positive PCR test for coronavirus, resulting in a Bayesian estimated prevalence of 0.12% (95% probability interval 0-0.26%). There were no reports of healthcare worker infections linked to elective surgery during and up to 2 weeks after the study period.

Conclusion: The prevalence of SARS-CoV-2 in asymptomatic elective surgical patients during a second wave was approximately 1 in 833. Given the very low likelihood of coronavirus transmission, and with existing current hospital capacity, recommencement of elective surgery should be considered. A coronavirus screening checklist should be mandated for surgical patients.

Abstract
Background: The study aimed to estimate the prevalence of active or previous SARS-CoV-2 infection in asymptomatic adults admitted for elective surgery in Australian hospitals. This surveillance activity was established as part of the National Pandemic Health Intelligence Plan.

Methods: Participants (n = 3037) were recruited from 11 public and private hospitals in four states (NSW, Vic, SA and WA) between 2 June and 17 July 2020, with an overall 66% participation rate. Presence of SARS-CoV-2 viral RNA was assessed by Reverse Transcriptase - Polymerase Chain Reaction (RT-PCR) analysis of nasopharyngeal swabs taken after induction of anaesthesia. Presence of anti-SARS-CoV-2 antibodies was assessed by analysis of serum collected at the same time using a novel dual-antigen ELISA assay.

Results: No patient (0/3010) returned a positive RT-PCR result. The Bayesian estimated prevalence of active infection of 0.02% (95% probability interval 0.00-0.11%), with the upper endpoint being 1 in 918. Positive serology (IgG) was observed in 15 of 2991 patients, with a strong positive in five of those individuals (Bayesian estimated seroprevalence 0.16%; 95% probability interval 0.00-0.47%).

Conclusion: These results confirm that during periods of low community prevalence of SARS-CoV-2 elective surgery patients without fever or respiratory symptoms had a very low prevalence of active SARS-CoV-2 infection.

Abstract
The risk of COVID-19 in those with chronic pain is unknown. We investigated whether self-reported chronic pain was associated with COVID-19 hospitalisation or mortality. UK Biobank recruited 502,624 participants aged 37 to 73 years between 2006 and 2010. Baseline exposure data, including chronic pain (>3 months, in at least 1 of 7 prespecified body sites) and chronic widespread pain (>3 months, all over body), were linked to COVID-19 hospitalisations or mortality. Univariable or multivariable Poisson regression analyses were performed on the association between chronic pain and COVID-19 hospitalisation and Cox regression analyses of the associations with COVID-19 mortality. Multivariable analyses adjusted incrementally for sociodemographic confounders, then lifestyle risk factors, and finally long-term condition count. Of 441,403 UK Biobank participants with complete data, 3180 (0.7%) were hospitalised for COVID-19 and 1040 (0.2%) died from COVID-19. Chronic pain was associated with hospital admission for COVID-19 even after adjustment for all covariates (incidence rate ratio 1.16; 95% confidence interval [CI] 1.08-1.24; P < 0.001), as was chronic widespread pain (incidence rate ratio 1.33; 95% CI 1.06-1.66; P = 0.012). There was clear evidence of a dose-response relationship with number of pain sites (fully adjusted global P -value < 0.001). After adjustment for all covariates, there was no association between chronic pain (HR 1.01; 95% CI 0.89-1.15; P = 0.834) but attenuated association with chronic widespread pain (HR 1.50, 95% CI 1.04-2.16, P -value = 0.032) and COVID-19 mortality. Chronic pain is associated with higher risk of hospitalisation for COVID-19, but the association with mortality is unclear. Future research is required to investigate these findings further and determine whether pain is associated with long COVID.

Abstract
Introduction: The global COVID-19 pandemic highlighted the importance of protecting frontline healthcare workers from novel respiratory infections while also exposing the limited instruction that medical students receive on proper donning of personal protective equipment (PPE) and more importantly the safe doffing of contaminated PPE to minimize their risk of nosocomial infection. The best methods of providing this kind of instruction have not yet been determined.

Methods: Anesthesiology interns and CA-1 residents were trained on proper PPE donning and doffing for AGPs using a methodology based on Miller's pyramid and following a "knows-knows how-shows-does" progression. Participants donned PPE without instruction and were sprayed with Glo Germ® to identify areas of contamination, after which they received both video and in-person instruction on best practices for donning and doffing PPE for AGPs. Following instruction, they again donned PPE and were sprayed with Glo Germ® to identify areas of contamination.

Results: 54 participants completed the study. Before training, overall donning compliance was 60% and overall doffing compliance was 48%. Overall, 70% were contaminated after PPE doffing, with 46% having multiple sites of contamination. After training, donning compliance increased by nearly 30% (P < 0.001), doffing compliance increased by over 20% (P < 0.001), and overall contamination decreased by nearly 30% (P = 0.029), with multiple-site contamination decreasing to only 6% (P = 0.013).

Discussion: While best methods for providing instruction regarding topics such as PPE donning and doffing have not yet been determined, we have demonstrated that the underlying knowledge base from medical school regarding proper donning and doffing for respiratory isolation is insufficient for preventing self-contamination, and that Miller's pyramid-based training using both video and in-person instruction combined with task execution by learners can improve compliance with PPE donning and doffing protocols and more importantly decrease skin contamination among a group of early training anesthesiology residents.

Abstract
Purpose: The aim of this study was to determine the changes in the physical, mental, and social conditions of operating room nurses and their personal experiences during the COVID-19 pandemic.

Design: The study applied a qualitative research design that included the content analysis method.

Methods: Face-to-face interviews were conducted online with 26 operating room nurses. Analysis of the data was completed in six steps using the content analysis method.

Findings: Four main themes emerged from the interviews: physical effect of the COVID-19 pandemic on operating room nurses, psychological effect of the COVID-19 pandemic on operating room nurses, operating room nurses' perceptions on the training given to them during the COVID-19 pandemic, and effects of the COVID-19 pandemic on health care worker and patient safety and nursing care.

Conclusions: This study contributes new findings on the experiences of operating nurses during the COVID-19 pandemic to the relevant literature. The results of the study indicated that the nurses were negatively affected both physically and psychologically during this period, and that this directly affected patient care.

Abstract
Background: Intensive care unit (ICU) patients with Coronavirus disease 2019 (COVID-19) have an increased risk of thromboembolic complications. We describe the occurrence of thromboembolic and bleeding events in all ICU patients with COVID-19 in Denmark during the first and second waves of the pandemic.

Methods: This was a sub-study of the Danish Intensive Care Covid database, in which all patients with SARS-CoV-2 admitted to Danish ICUs from 10th March 2020 to 30th June 2021 were included. We registered coagulation variables at admission, and all thromboembolic and bleeding events, and the use of heparins during ICU stay. Variables associated with thrombosis and bleeding and any association with 90-day mortality were estimated using Cox regression analyses.

Results: We included 1369 patients in this sub-study; 158 (12%, 95% confidence interval 10-13) had a thromboembolic event in ICU and 309 (23%, 20-25) had a bleeding event, among whom 81 patients (6%, 4.8-7.3) had major bleeding. We found that mechanical ventilation and increased D-dimer were associated with thrombosis and mechanical ventilation, low platelet count and presence of haematological malignancy were associated with bleeding. Most patients (76%) received increased doses of thromboprophylaxis during their ICU stay. Thromboembolic events were not associated with mortality in adjusted analysis (hazard ratio 1.35 [0.91-2.01, p = .14], whereas bleeding events were 1.55 [1.18-2.05, p = .002]).

Conclusions: Both thromboembolic and bleeding events frequently occurred in ICU patients with COVID-19. Based on these data, it is not apparent that increased doses of thromboprophylaxis were beneficial.

Abstract
Background: Under the hypothesis that mechanical power ratio could identify the spontaneously breathing patients with higher risk of respiratory failure, we assessed lung mechanics in non-intubated patients with COVID-19 pneumonia aimed at: 1) describe their characteristics; 2) compare lung mechanics between patients who received respiratory treatment escalation and those who did not; 3) identify variables associated with the need for respiratory treatment escalation.

Methods: Secondary analysis of prospectively enrolled cohort involving 111 consecutive spontaneously breathing adults receiving continuous positive airway pressure, enrolled from September 2020 to December 2021. Lung mechanics, other previously reported predictive indices were calculated, as well as a novel variable: the mechanical power ratio (the ratio between the actual and the expected baseline mechanical power). Patients were grouped according to the outcome: 1) no-treatment escalation (patient supported in continuous positive airway pressure until improvement); 2) treatment escalation (escalation of the respiratory support to non-invasive or invasive mechanical ventilation); and the association between lung mechanics/predictive scores and outcome was assessed.

Results: At day 1, patients undergoing treatment escalation had similar spontaneous tidal volume than patients who did not (7.1 ± 1.9 vs 7.1 ± 1.4 mL/KgIBW; p=0.990). In contrast, they showed higher respiratory rate (20 ± 5 vs 18 ± 5 bpm; p=0.028), minute ventilation (9.2 ± 3.0 vs 7.9 ± 2.4 L/min; p=0.011), tidal pleural pressure (8.1 ± 3.7 vs 6.0 ± 3.1 cmH2O; p=0.003), mechanical power ratio (2.4 ± 1.4 vs 1.7 ± 1.5; p=0.042) and lower PaO2/FiO2 (174 ± 64 vs 220 ± 95; p=0.007). Mechanical power (AUC 0.738 [95%CI 0.636-0.839] p<0.001), the mechanical power ratio (AUC 0.734 [95%CI 0.625-0.844] p <0.001) and the pressure-rate index (AUC 0.733 [95%CI 0.631-0.835] p <0.001) showed the highest AUC.

Conclusions: In this COVID-19 cohort, tidal volume was similar in patients undergoing treatment escalation and in patients who did not; mechanical power, its ratio, and pressure-rate index were the variables presenting the highest association with the clinical outcome.

Abstract
Introduction: COVID-19 is associated with severe respiratory distress and high mortality. We investigated the evolution of the respiratory mechanics in COVID-19 acute respiratory distress syndrome (ARDS) and the occurrence of a restrictive respiratory pattern.

Material and methods: A retrospective, single-centre study including patients admitted to the ICU during the first wave of the pandemic (March-April 2020).

Results: A total of 141 consecutive patients were included. Many patients developed a restrictive pattern of respiratory mechanics during the course of the disease. Fifty-two patients died in the hospital (36.8%). In 29 cases (58% of the deceased) death was associated with a pattern of pulmonary mechanics, indicating a restrictive evolution of ARDS. Other diagnoses related to death were pulmonary embolism (n = 7, 14%), septic shock (n = 17, 33%), and other causes (n = 10, 20%), with some patients combining at least 2 of these diagnoses. In a multivariate analysis, age (OR = 1.06; 95% CI: 1.01-1.12; P = 0.029) and the administration of steroid pulses (OR = 2.7; 95% CI: 1.1-6.8; P = 0.03) were associated with the development of a restrictive pulmonary pattern and a higher level of plasmatic interleukin-6.

Conclusions: COVID-19 ARDS is associated with high mortality associated with a specific pattern of respiratory mechanics and sustained activation of innate immunological response. Age and administration of high-dose steroid pulses are associated with this clinical picture.

Abstract
Objectives: To determine in patients with acute respiratory distress syndrome (ARDS) on venovenous extracorporeal membrane oxygenation (VV ECMO) whether reducing driving pressure (ΔP) would decrease plasma biomarkers of inflammation and lung injury (interleukin-6 [IL-6], IL-8, and the soluble receptor for advanced glycation end-products sRAGE).

Design: A single-center prospective physiologic study.

Setting: At a single university medical center.

Participants: Adult patients with severe COVID-19 ARDS on VV ECMO.

Interventions: Participants on VV ECMO had the following biomarkers measured: (1) pre-ECMO with low-tidal-volume ventilation (LTVV), (2) post-ECMO with LTVV, (3) during low-driving-pressure ventilation (LDPV), (4) after 2 hours of very low driving-pressure ventilation (V-LDPV, main intervention ΔP = 1 cmH2O), and (5) 2 hours after returning to LDPV.

Main measurements and results: Twenty-six participants were enrolled; 21 underwent V-LDPV. There was no significant change in IL-6, IL-8, and sRAGE from LDPV to V-LDPV and from V-LDPV to LDPV. Only participants (9 of 21) with nonspontaneous breaths had significant change (p < 0.001) in their tidal volumes (Vt) (mean ± SD), 1.9 ± 0.5, 0.1 ± 0.2, and 2.0 ± 0.7 mL/kg predicted body weight (PBW). Participants with spontaneous breathing, Vt were unchanged-4.5 ± 3.1, 4.7 ± 3.1, and 5.6 ± 2.9 mL/kg PBW (p = 0.481 and p = 0.065, respectively). There was no relationship found when accounting for Vt changes and biomarkers.

Conclusions: Biomarkers did not significantly change with decreased ΔPs or Vt changes during the first 24 hours post-ECMO. Despite deep sedation, reductions in Vt during V-LDPV were not reliably achieved due to spontaneous breaths. Thus, patients on VV ECMO for ARDS may have higher Vt (ie, transpulmonary pressure) than desired despite low ΔPs or Vt.

Abstract
Background: Chronic pain symptoms are distressing conditions that necessitate regular visits to pain therapists and may require interventions, however, the COVID-19 pandemic has caused patients and their therapists to limit both visits and interventions with the transition to telehealth, with little or no preparation or training. This has resulted in the extensive use of over-the counter analgesia and corticosteroids.

Objectives: Our study aimed to evaluate the effect of the COVID-19 pandemic on the rates of counseling and interventional pain management therapies (IPMT), and determine the effects of implementing an infection control program (ICP) and mandating personal protective equipment (PPE) on these rates.

Study design: Prospective multicenter survey, based on an online self-assessed questionnaire.

Setting: Departments of Anesthesia, Pain, Intensive Care Unit, Physical Medicine, Rheumatology, and Rehabilitation at Egyptian University hospitals.

Methods: A self-assessed questionnaire was uploaded on Google forms and links were sent to enrolled therapists with an identification number to allow self-administration and privacy. Feedback was analyzed by 2 authors who were blinded to the identity of the responders.

Results: A total of 57.9% of responders increased their patients' contact by phone and video conference. Within 1-4 months after the outbreak began, 59% stopped in-person contact and 38.2% stopped their IPM practice. Prescriptions of analgesics and oral steroids increased by about 50%. The majority of responders complained of a shortage of ventilation appliances in their workplaces. About 50% of them always use ICP, 85% use surgical masks, 61% use gloves, and 45% wear gowns when meeting with patients. After the application of PPE, 45.5% of responders increased their consultation rate and 40% increased their rate of IPMT.

Limitations: This study is limited to being a national study, and so lacked comparative data.

Conclusion: The COVID-19 outbreak seriously affected the rates of in-person consultations and IPMT for patients with chronic pain and increased the rates of consumption of analgesia and oral steroids. Most responders reported a shortage of PPE especially ventilation appliances in workplaces. A high percentage of responders lack interest in ICP and PPE, despite the positive effects of its application on consultation and IPMT rates.