Airway management: Journals & articles

Abstract
Anaesthetic airway incidents persist as a significant concern in patient safety and, despite extensive investigations, continue to cause patient harm. Traditional safety investigations predominantly adhere to Safety-I principles, focusing on identifying and rectifying errors, often yielding limited new findings. In this analysis conducted within the webAIRS database, the focus shifted towards Safety-II principles. The aim of this study was to identify factors contributing to airway management safety by examining incidents that did not result in adverse patient outcomes. Incidents categorised as 'difficult intubation' or 'failed intubation' without causing harm to the patient and reported to webAIRS between 2016 and 2022, were included in the analysis.An inductive qualitative content analysis of narrative data from 129 such incidents revealed that the majority of reported events depicted scenarios deviating from controlled and planned circumstances. During the analysis four themes were identified: patient factors, system factors, individual anaesthetist factors and airway management strategy. Within the first three themes, multiple factors were linked to airway management strategies. The findings of this qualitative analysis show that 'Work as done' often differs from 'Work as imagined'.This qualitative analysis highlighted the dynamic nature of human management, as individuals respond to unplanned or unexpected events, showcasing adaptability and positive contributions to incident performance. Expanding the understanding of patient safety to also include Safety-II principles, provides a deeper and wider understanding of airway management safety.

Abstract in English, French
Purpose: When difficulty with laryngoscopy is encountered, confirmation of endotracheal access can be confirmed using the tactile feedback (i.e., tracheal clicks) of a tracheal tube introducer (bougie). There is anecdotal evidence that a bougie placed in the esophagus may have a unique, tactile "boggy" resistance. In this study, we aimed to elucidate the sensitivity and specificity of clicks and boggy resistance for infrequent airway providers in cadaveric airways.

Methods: We conducted a prospective observational study using descriptive statistics to examine the diagnostic accuracy of clicks and boggy resistance for bougies placed in cadaveric airways. We recruited prehospital providers from within Atlantic Canada who then underwent a brief formal training protocol. Cadavers were equipped with a static laryngoscope and bougie (placed either in the trachea or esophagus). Each participant, blinded to bougie placement, was then tested on two separate cadavers and asked whether they felt clicks and/or boggy resistance.

Results: Thirty-seven paramedics participated in the study (32 advanced care paramedics, five critical care paramedics) and were randomized to perform 74 bougie assessments on cadaveric airways. For tracheal clicks, we calculated an overall sensitivity of 86% (95% confidence interval [CI], 75 to 98) and an overall specificity of 81% (95% CI, 68 to 94). Sensitivity for the esophageal boggy resistance test was 78% (95% CI, 65 to 92) while specificity was 86% (95% CI, 75 to 98).

Conclusion: Following a brief training session, prehospital providers who intubate infrequently seemed to show a relatively high degree of accuracy using tracheal clicks and esophageal boggy resistance to confirm bougie placement in cadaveric airways.

Abstract
Airway management in children poses unique challenges due to the different anatomy, physiology, and pathophysiology across the pediatric age span. The recently published joint European Society of Anaesthesiology and Intensive Care-British Journal of Anaesthesia (ESAIC-BJA) neonatal and infant airway management guidelines provide recommendations and suggestions to support clinicians in deciding the best strategy. These guidelines represent a framework with the most recent and up-to-date evidence, from the initial assessment to the management of normal and difficult airways up to the extubation phase. However, such guidelines have intrinsic limitations due to the lack of supporting evidence in various fields of airway management. Pediatric institutions should adopt guidelines after careful internal review according to the local circumstances, including caseload, equipment and expertise. The current narrative review focused on providing references and practical tips on pediatric airway management, which is still not completely elucidated. Moreover, the authors put particular emphasis on the influence of human factors on the overall success of tracheal intubation, the incidence of complications, and the outcomes for patients.

Abstract
Introduction: Difficult or failed intubation significantly increases the risk of morbidity and mortality. Documentation of a prior difficult or failed tracheal intubation is a strong predictor of future difficult intubation.

Methods: We undertook a quality improvement project to create a redesigned difficult intubation alert with increased visibility in our electronic health record. We sought to determine whether this redesigned alert would be associated with a reduced incidence of difficult intubations. After reviewing many intubation procedure notes, we chose the following criteria to define a predicted future difficult intubation: requiring an awake technique, ease of intubation procedure charted as "difficult" or "unable", procedure requiring flexible bronchoscopy, a procedure requiring three or more attempts, and intubation with a grade three or four view during laryngoscopy. Patients meeting one or more of the above criteria were included in our study. An intervention was implemented which consisted of the introduction of a new difficult intubation alert that could easily be applied to a patient's chart by anyone on the anesthesia team. Further, if the anesthesia clinician filling out the intubation procedure note charted an intubation procedure as "difficult" or "unable", they were prompted by a pop-up asking if difficult intubation should be added to the patient's problem list. If yes was clicked, the electronic alert was activated, and a large red banner appeared. Outcomes included the number of patients who had the difficult intubation label in the pre-intervention period, the number of patients who had the new difficult intubation alert in the post-intervention period, the number of records with ease of intubation procedure charted as "difficult" or "unable", the number of records requiring three or more attempts at intubation, and the number of records with grade three or four view charted at intubation.

Results: There was an expected increase in the application of the difficult intubation alert from 9% of patients with a difficult intubation label in the pre-intervention period to 38% with the redesigned alert in the post-intervention period which was statistically significant (p<0.001). In the 21 months prior to the introduction of the alert, our screening process identified 988 records as predicted difficult intubations. Of these, 672 (68%) were charted by the intubating clinician as actual difficult intubations with 32% not being recorded as difficult. During the 20 months after the end of the interim period, the screening process identified 976 predicted difficult intubations with intubating anesthesia clinicians charting 416 (42%) of them as actual difficult intubations and 58% found not to be difficult. This reduction in monthly median percent of actual difficult intubations was statistically significant (p<0.001).

Conclusions: The introduction of a difficult intubation alert at our institution was associated with a reduced incidence of difficult intubation.

Abstract in English, French
Purpose: There is significant variability in the application of positive end-expiratory pressure (PEEP) in patients undergoing invasive mechanical ventilation. There are numerous studies assessing methods of determining optimal PEEP, but many methods, patient populations, and study settings lack high-quality evidence. Guidelines make no recommendations about the use of a specific method because of equipoise and lack of high-quality evidence. We conducted a scoping review to determine which methods of determining optimal PEEP have been studied and what gaps exist in the literature.

Source: We searched five databases for primary research reports studying methods of determining optimal PEEP among adults undergoing invasive mechanical ventilation. Data abstracted consisted of the titration method, setting, study design, population, and outcomes.

Principle findings: Two hundred and seventy-one studies with 17,205 patients met the inclusion criteria, including 73 randomized controlled trials (RCTs) with 10,733 patients. We identified 22 methods. Eleven were studied with an RCT. Studies enrolled participants within an intensive care unit (ICU) (216/271, 80%) or operating room (55/271, 20%). Most ICU studies enrolled patients with acute respiratory distress syndrome (162/216, 75%). The three most studied methods were compliance (73 studies, 29 RCTs), imaging-based methods (65 studies, 11 RCTs), and use of PEEP-FIO2 tables (52 studies, 20 RCTs). Among ICU RCTs, the most common primary outcomes were mortality or oxygenation. Few RCTs assessed feasibility of different methods (n = 3). The strengths and limitations of each method are discussed.

Conclusion: Numerous methods of determining optimal PEEP have been evaluated; however, notable gaps remain in the evidence supporting their use. These include specific populations (normal lungs, patients weaning from mechanical ventilation) and using alternate outcomes (ventilator-free days and feasibility) and they present significant opportunities for future study.

Study registration: Open Science Framework ( https://osf.io/atzqc ); first posted, 19 July 2022.

Abstract
Endotracheal tubes (ETTs) are life-supporting devices that are designed to maintain a patent airway in patients who are unable to sustain an airway due to illness or injury. Patients with small airways, such as neonates and pediatrics, have unique structural and functional features, making it essential that ETT design considers and executes on these particular needs. Though uncuffed ETTs have historically been preferred for patients younger than eight years of age, advances in cuffed ETT design and construction can be utilized to manufacture ETTs that are optimized for the smallest, most fragile airways. The purpose of this article is to discuss certain design features of cuffed ETTs in respect to small airways.

Abstract
Purpose: Comparing the outcomes of video-laryngoscopy and flexible fiberoptic bronchoscopy for endotracheal intubation in patients with cervical spine immobilization.

Methods: All of the comparative studies published in the PubMed, Cochrane Library, Medline, Web of Science, and EMBASE databases as of 8 Jan 2024 were included. All outcomes were analyzed using Review Manager 5.4. The primary outcomes were the successful first-attempt intubation rate, intubation time, heart rate after intubation, mean arterial pressure after intubation, overall intubation success rate, risk of tissue damage and sore throat.

Results: The meta-analysis included six randomized controlled studies with a total of 694 patients. The outcomes of the meta-analysis revealed that the use of video laryngoscopy was better than flexible fiberoptic bronchoscopy in terms of the successful first-attempt intubation rate (P<0.05) and intubation time (P<0.05) in patients with cervical spine immobilization. However, there were no statistically significant differences in heart rate after intubation, mean arterial pressure after intubation, overall intubation success rate, risk of tissue damage, or sore throat (all P>0.05) between the video laryngoscopy and flexible fiberoptic bronchoscopy groups.

Conclusions: Compared with flexible fiberoptic bronchoscopy, video laryngoscopy has superior tracheal intubation performance in terms of the first-attempt success rate and intubation speed. This finding was observed in patients with cervical spine immobilization who utilized a cervical collar to simulate a difficult airway. Additionally, both types of scopes demonstrated similar complication rates. Current evidence suggests that video laryngoscopy is better suited than flexible fiberoptic bronchoscopy for endotracheal intubation in patients immobilized with a cervical collar.

Abstract
Purpose: Whether endotracheal tube (ETT) configuration (cuffed or uncuffed) influences the occurrence of respiratory adverse events (RAEs) in patients at risk remains largely unknown. We investigated the effects of cuffed ETTs on RAE occurrence after extubation in pediatric patients with airway hypersensitivity.

Methods: Children aged < 8 years with increased airway hypersensitivity (defined as upper airway symptoms, recent upper respiratory infection within 2 weeks, or a history of asthma) who underwent general endotracheal anesthesia with inhaled agents between January 2021 and December 2022 were included. We retrospectively examined the patients' background and intraoperative anesthesia conditions by comparing the cuffed and uncuffed ETT groups. Multiple logistic regression analysis was performed to estimate the association between ETT configuration (cuffed vs. uncuffed) and the occurrence of RAEs or respiratory interventions (laryngospasm, peripheral capillary oxygen saturation < 92%, oxygen supplementation, epinephrine inhalation, or reintubation) after extubation.

Results: Cuffed ETTs were used in 163 patients and uncuffed ETTs in 143 patients. Apart from the frequency of upper airway surgery and intraoperative fluid balance, no significant differences in background characteristics were observed between the groups. RAEs after extubation were observed in 36 (22.1%) and 28 (19.6%) patients in each cuffed and uncuffed ETT groups. After adjusting for known RAE risk factors, no difference was observed in RAEs or respiratory interventions after extubation between both groups (odds ratio, 1.14; 95% confidence interval: 0.64, 2.06).

Conclusion: In pediatric patients with airway hypersensitivity, the use of cuffed ETTs did not increase the occurrence of RAEs or respiratory interventions after extubation.

Keywords: Airway hypersensitivity; Children; General anesthesia; Intubation; Risk factors.

Abstract
The post-total laryngectomy airway poses perioperative challenges to anesthesia management. While endobronchial intubation is a cited complication, a low-lying stoma may increase this risk. Furthermore, the stoma's proximity to a median sternotomy increases surgical and airway management complexity. This report highlights a case of endobronchial intubation in a patient with a low-lying stoma who presented for coronary artery bypass graft. With a stoma at the upper border of the sternum, intraoperative innovation was required to prevent endobronchial intubation while remaining out of the surgical field. This innovation may be useful in urgent surgical situations.

Abstract
Tracheobronchomalacia refers to an abnormally excessive collapse of the trachea and/or bronchi during exhalation. In the pediatric population, tracheobronchomalacia is increasingly recognized as a cause of morbidity and mortality. Historically, options for medical management and surgical intervention were limited, and patient outcomes were poor. Over the last decade, select US pediatric institutions have devoted significant resources to the establishment of dedicated surgery and anesthesia teams and the development of novel techniques for the successful identification, assessment, and surgical correction of tracheobronchomalacia in a highly complex subset of the pediatric population. The close communication, collaboration, and evolution of anesthesia techniques to meet the unique requirements of new surgical procedures have greatly improved patient safety and optimized outcomes. More than 800 cases have been performed across 2 US pediatric institutions using these techniques. This article reviews the posterior tracheopexy procedure, a newer but increasingly common surgery designed to address tracheobronchomalacia, and provides an overview of related anesthesia considerations and unique challenges. In addition, this article describes novel anesthesia techniques developed specifically to facilitate optimal diagnosis of tracheobronchomalacia and intraoperative management of posterior tracheopexy and similar airway surgeries. These include methods to safely enable 3-phase rigid dynamic bronchoscopy for accurate tracheobronchomalacia diagnosis, recurrent laryngeal nerve monitoring during cervical and thoracic surgical dissection, continuous intraoperative bronchoscopy to enable real-time images during airway reconstruction, and intraoperative assessment of airway repair adequacy to ensure successful correction of tracheobronchomalacia.

Abstract
After an induction dose of rocuronium, sugammadex in a dose of 16 mg.kg-1 has been shown to provide early reversal of the neuromuscular blockade. However, the use of sugammadex to rescue a "cannot intubate, cannot ventilate" (CICV) scenario remains controversial. The aim of this systematic review was to discuss case reports describing the use of sugammadex as a rescue reversal in CICV scenarios and analyze the influencing factors potentially shaping the outcome of such reversal. The study has been registered on International Prospective Register of Systematic Reviews (PROSPERO) (CRD42024514255). We conducted a systematic review of the literature using PubMed, Medline, and Embase. Records were included if they were case reports or case series published in peer-reviewed journals, describing the administration of sugammadex as a rescue reversal in CICV scenarios, and including clinical outcomes and details of the management. Sources were last searched on November 30, 2023. The articles selected were initially screened based on their titles and abstracts, and then complete articles were examined to determine their eligibility and compliance with the inclusion criteria. Two independent authors evaluated the quality of the individual studies using the Joanna Briggs Institute Critical Appraisal Checklist for Case Reports. Eight articles were included in our review. In all patients, CICV scenarios were declared minutes following induction. In 6/8 cases (75%), adequate spontaneous ventilation was restored after the administration of sugammadex. In the remaining 2 cases, sugammadex administration resulted in an obstructed pattern of breathing, and surgical airway was the successful rescue technique. There was wide variability in the sugammadex dose with a median (range) of 14 (5-16) mg.kg-1 and median timing (range) from rocuronium administration of 6 (2-10) minutes. This case-report-based review is susceptible to reporting bias and may not encompass all pertinent data and adverse events. Also, cases with both favorable and unfavorable outcomes may have not been published, and the heterogeneity of cases limits the ability to draw definitive conclusions. In summary, although these case reports suggest that sugammadex might be helpful in CICV scenarios, further research is needed to confirm its effectiveness. However, due to the rare occurrence of CICV events, gathering sufficient data for conclusive evidence may be challenging.

Abstract
The purpose of this study is to investigate whether preoperative intubation simulation using custom-made simulator is useful during anesthesia induction for the children who have difficult airway. We included the children under 15 years of age who have difficult airway which had been already known. Prior to the scheduled surgery, CT imaging was performed and a 3D reconstruction of the face from the chest was performed. Then custom-made airway simulator was made. We tried to intubate custom-made simulator of patients preoperatively. We planned how to intubate the patient for anesthesia induction from the result of intubation simulation. The findings of direct laryngoscopy were compared with the findings during intubation. Three patients were included in this study. It took up to 3 weeks to create a simulator, which was difficult due to time constraints to accommodate emergency surgeries. Simulation findings correlated well with findings during anesthesia induction. There were no cases of severe hypotension or hypoxia during induction of anesthesia with the planned intubation method. In conclusion, preoperative intubation simulation using custom-made simulator may be useful for the patients who have difficult airway.

Abstract
Background: Self-expandable metallic stents (SEMS) are increasingly used in the management of both malignant and nonmalignant airway stenosis. There are multiple stents available in the market; however, the current literature on the efficacy and safety of newly available 3rd generation SEMS (Bonastent) is extremely limited and only has data from single center studies.

Objectives: To report the efficacy and early (<7 days) and late (⩾7 days) complications in patients with central airway obstruction (CAO) treated with Bonastent placement at two institutions.

Design: We performed a retrospective analysis of data of consecutive patients who underwent therapeutic bronchoscopy and Bonastent placement at two tertiary care university hospitals between January 2019 and November 2023.

Methods: Bonastent deployment was performed in the operating room. Stents were deployed using rigid or flexible bronchoscopy under direct visualization with a flexible bronchoscope and in conjunction with fluoroscopic guidance. We then analyzed the effectiveness, short-term, and long-term complications of Bonastent placement.

Results: A total of 107 Bonastents® were placed in 96 patients. The most common etiology of CAO was malignancy, 92.7% (n = 89), followed by excessive dynamic airway collapse (EDAC) and post-intubation tracheal stenosis. Seventy-three patients (76%) had improvement in symptoms or imaging within 7 days of stent placement, including successful liberation from mechanical ventilation in a patient with CAO. Early complications occurred in seven patients (two-airway bleeding, two-mucus plugging that improved with airway clearance, two-stent migrations, and one-cough).Late complications occurred in 23 patients (1-stent migration requiring revision bronchoscopy and replacement of airway stent, 11-mucus plugging, 6-granulation tissue, 2-pneumonia, 1-cough, 1-tumor ingrowth/stent fracture, 1-airway emergency due to excessive granulation tissue obstructing the distal end of the stent and had a failed cricothyroidotomy leading to death). Overall, the early complication rate was 7.3% (7/96) and late complication rate was 23.9% (23/96).

Conclusion: Our study is the first multicenter study that found a good safety profile with a low complication rate after tracheobronchial Bonastent placement with improvement in symptoms soon after stent placement.

Abstract
Background: An effective airway management education program is a crucial part of the undergraduate medical education curriculum. Theoretical instructions and practical demonstrations are the major modalities of medical education in Nepal. Simulation-based education (SBE) programs have not yet been implemented effectively. The authors aimed to determine the effects of an SBE program on the knowledge, skills, and perceived confidence of medical interns regarding emergency airway management.

Methods: This mixed methods study comprised both quantitative and qualitative components. The study participants were 47 medical interns who had participated in the SBE program.

Results: The mean age of the 47 participants was 24.74 years. There were 33 (70.21%) male and 14 (29.79%) female participants. The knowledge, skills, and perceived confidence scores of the participants for airway management preparation, basic airway management, endotracheal intubation, and laryngeal mask airway (LMA) insertion improved significantly following the SBE program (P<0.001). Analysis of the participants' feedback indicated that they largely approved of the SBE program. The majority of students and faculty expressed a willingness to include similar programs in the undergraduate medical education curriculum.

Conclusion: This study demonstrated through quantitative and qualitative metrics that SBE can enhance the knowledge, skills, and perceived confidence in performing emergency airway management among medical interns. The authors recommend measures to include and effectively implement SBE in the undergraduate medical education curriculum of Nepal.

Abstract in English, French
Purpose: The modified Mallampati classification is part of the preoperative airway risk assessment. Inconsistency in the way it is examined may contribute to heterogeneity in its diagnostic performance. The best visible Mallampati score could reduce interobserver heterogeneity but its diagnostic characteristics remain unknown.

Methods: During preoperative anesthesia consultation of adult patients with a senior anesthesiologist, we compared the modified Mallampati classification score vs the best visible Mallampati score using cervical extension, tongue in, and phonation. The primary outcome was the diagnostic characteristic of the modified Mallampati classification score vs the best visible Mallampati score as predictors of difficult orotracheal intubation (more than two direct laryngoscopies or need for an alternate device). We performed a multivariable analysis to identify independent predictors of difficult orotracheal intubation in the tested cohort.

Results: Difficult orotracheal intubation occurred in 77/3,243 (2.4%) patients. A best visible Mallampati score was obtained in 1,596 (49.2%) patients. Sensitivity and specificity of the modified Mallampati classification score for predicting difficult orotracheal intubation were 0.56 (95% confidence interval [CI], 0.44 to 0.66) and 0.69 (95% CI, 0.68 to 0.71), respectively. By comparison, the best visible Mallampati score was less sensitive (difference, -0.30; 95% CI, -0.19 to -0.30; P < 0.001) but more specific (difference, 0.24; 95% CI, 0.22 to -0.25; P < 0.001). In patients with difficult orotracheal intubation, 53% were incorrectly reclassified as low risk by the best visible Mallampati score.

Conclusion: Compared with the modified Mallampati classification score, the best visible Mallampati score decreased sensitivity for predicting difficult orotracheal intubation and falsely classified half of the patients with difficult orotracheal intubation. Taking the risks associated with difficult airways into account, our findings indicate that a careful examination of the modified Mallampati classification is required during the global preoperative airway examination.

Study registration: ClinicalTrials.gov ( NCT02788253 ); 9 February 2016.

Keywords: Mallampati classification; airway; difficult tracheal intubation; laryngoscopy; physical

Abstract
Postoperative lingual nerve injury is a rare but serious complication following airway management and can lead to significant discomfort and disability. This literature review explores the aetiology, clinical presentation, management strategies and potential preventive measures for lingual nerve injuries associated with airway management during surgery. A search of PubMed, MEDLINE, EMBASE Science Direct, Cochrane library and Web of Science databases was done since inception to January 2024, including any observational studies and clinical trials describing patients diagnosed with lingual nerve injury following airway instrumentation. Multiple risk factors for lingual nerve injury were identified. Anaesthesia factors include difficulty with intubation and use of laryngeal mask airway. Surgical factors are long duration of operation and surgery of the head and neck. Patient factor includes female sex. Anaesthetists should proactively inform patients about the potential for this nerve injury and control modifiable risk factors to mitigate the risk of injury.

Abstract
The authors have conducted a retrospective analysis based on two cases of patients with intra-tracheal pathologies who received treatment from the same surgeon at a tertiary referral center. The effective management of airways in patients with intra-tracheal lesions necessitates close collaboration between surgeons and anesthesiologists. Factors such as the size, location, rigidity of the tumor, and the remaining tracheal lumen space should be carefully considered. In situations where there is near complete obstruction of the trachea and a substantial risk of worsened respiratory function, resorting to cardiopulmonary bypass or extracorporeal membrane oxygenation is advisable. This pilot study aims at devising an algorithm for the airway management of intra-tracheal lesions, although a larger case cohort is needed to assess its applicability and effectiveness.

Abstract
Background: Double-lumen tubes (DLTs) and bronchial blockers (BBs) can be used to establish one-lung ventilation (OLV) for thoracic surgery. BBs are a good alternative when DLTs are not suitable or patients have difficult airways. However, BBs are more prone to malposition, leading to adverse events.

Case presentation: We present a 68-year-old male patient who was scheduled for thoracoscopic left lower lobectomy. The patient was not expected to have airway malformation preoperatively. When the DLT could not be inserted into the bronchus after general anesthesia induction, we used a BB to perform OLV. During surgery, malposition of the BB resulted in the development of an "incomplete balloon valve", leading to a cardiopulmonary crisis.

Conclusions: Previewing chest computed tomography scans to assess the airway anatomy before thoracic surgery is essential. Three-dimensional reconstruction of the airway can provide a more intuitive assessment of airway anatomy. During OLV with BBs, we should pay attention to balloon malposition to prevent cardiopulmonary crises.

Abstract
This study aimed to investigate the relationship between cervical measurements and difficult airways using ultrasonographic measurements. American Society of Anesthesiologists grade I to III, male or female, 120 adult patients, undergoing elective surgery were enrolled in the study. The study involved measuring the distance of the trachea, cricoid cartilage, thyroid cartilage, vocal cord anterior commissure, and hyoid bone to the skin using a 10 to 13 MHz linear ultrasound probe in the transverse plane. Additionally, the length of the cricothyroid and thyrohyoid membranes, along with their distance from the skin, were measured using the probe in the sagittal plane. Subsequently, another experienced anesthesiologist conducted mask ventilation and intubation after the patient's induction of general anesthesia. Throughout this process, the patient was assessed for difficulties in mask ventilation, laryngoscopy, and intubation. 28 (23.3%) patients had a difficult airway. Analyzing the measurements associated with difficult airways, the most reliable predictor was the epiglottis midline-skin distance [AUC (area under the curve): 0.847, P < .001, cutoff: >19.9, sensitivity: 78.6%, specificity: 79.4%]. Additionally, other factors such as hyoid bone to skin distance, thyroid cartilage to skin distance, thyrohyoid membrane to skin distance, and vocal cord anterior commissure-skin distance were also identified as predictors for a difficult airway. The increase in the distance of the epiglottis midline, vocal cord anterior commissure, hyoid bone, thyrohyoid membrane, and thyroid cartilage to the skin at the level of the isthmus measured by ultrasonography is predictive of difficult airways. Based on our study outcomes, we assert that ultrasonographic evaluation can be used in the prediction of difficult airways.

Abstract
Purpose: The objective of this study was to evaluate whether adjusting the oxygen concentration guided by the Oxygen Reserve Index (ORI) during pediatric laryngeal surgery with High Flow Nasal Cannula Oxygen (HFNO) could achieve postoperative PaO2 close to physiological levels while ensuring adequate oxygenation in surgery.

Methods: Sixty pediatric patients undergoing laryngeal surgery or examination were randomly assigned to two groups. The ORI group received oxygen concentration adjustments every 5 min to maintain a target ORI value of 0.21, whereas the control group did not undergo any adjustments. Postoperative PaO2, time weighted average fraction of inspired oxygen (FiO2), and mean Peripheral Oxygen Saturation (SpO2) were compared between groups. Finally, some analyses were conducted to examine the relationship of ORI with PaO2.

Results: In general, the postoperative PaO2 was 164.9 ± 48.8 mmHg in ORI group and 323.0 ± 87.7 mmHg in control group (P < 0.01). The time weighted average FiO2 in the ORI group was 85.9 [81.8-92.7] %. There was no significant difference in mean SpO2 between the two groups (ORI vs. control: 98.4 [97.7-99.2] vs. 98.8 [97.7-99.5]; P = 0.36). According to the analyses, the optimal cut value for ORI was determined to be 0.195 when PaO2 was 150 mmHg.

Conclusions: In pediatric laryngeal surgery with HFNO, reducing oxygen concentration guided by ORI helped achieve postoperative PaO2 levels closer to physiological norms without compromising intra-operative oxygenation.

Abstract
Background: Mucopolysaccharidoses (MPSs) are rare congenital lysosomal storage disorders due to a deficiency of enzymes metabolising glycosaminoglycans, leading to their accumulation in tissues. This multisystem disease often requires surgical intervention, including valvular cardiac surgery. Adult MPSs have complex airways making anaesthesia risky. Methods: We report novel three-dimensional (3D) modelling airway assessments and multidisciplinary peri-operative airway management. Results: Five MPS adults underwent cardiac surgery at the national MPS cardiac centre (type I = 4, type II = 1; ages 20, 24, 33, 35, 37 years; two males, three females). All had complex airway abnormalities. Assessments involved examination, nasendoscopy, imaging, functional studies, 3D reconstruction, virtual endoscopy, virtual reality and simulation using computerised, physical modelling. Awake oral fibre-optic intubation was achieved via airway conduit. Staged extubation was performed on the first post-operative day under laryngo-tracheoscopic guidance. The post-operative period involved chest physiotherapy and occupational therapy. All patients had safe intubation, ventilation and extubation. Four had good cardiac surgical outcomes, one (MPS type I; age 35 years) was inoperable due to endocarditis. None had post-operative airway complications. Conclusions: Expertise from cardiovascular-heart team, multidisciplinary airway management, use of novel techniques is vital. Traditional airway assessments are insufficient, so ENT input, radiology and computerised methods to assess and simulate the airway in 3D by collaboration with clinical engineering is essential.

Abstract
Background: Atelectasis has been reported in 68 to 100% of children undergoing general anaesthesia, a phenomenon that persists into the recovery period. Children receiving recruitment manoeuvres have less atelectasis and fewer episodes of oxygen desaturation during emergence. The optimal type of recruitment manoeuvre is unclear and may be influenced by the airway device chosen.

Objective: We aimed to investigate the different effects on lung mechanics as assessed by the forced oscillation technique (FOT) utilising different recruitment strategies: repeated inflations vs. one sustained inflation and different airway devices, a supraglottic airway device vs. a cuffed tracheal tube.

Design: Pragmatic enrolment with randomisation to the recruitment strategy.

Setting: We conducted this single-centre trial between February 2020 and March 2022.

Participants: Seventy healthy patients (53 boys) aged between 2 and 16 years undergoing general anaesthesia were included.

Interventions: Forced oscillations (5 Hz) were superimposed on the ventilator waveform using a customised system connected to the anaesthesia machine. Pressure and flow were measured at the inlet of the airway device and used to compute respiratory system resistance and reactance. Measurements were taken before and after recruitment, and again at the end of surgery.

Main outcome measures: The primary endpoint measured is the change in respiratory reactance.

Results: Statistical analysis (linear model with recruitment strategy and airway device as factors) did not show any significant difference in resistance and reactance between before and after recruitment. Baseline reactance was the strongest predictor for a change in reactance after recruitment: prerecruitment Xrs decreases by mean (standard error) of 0.25 (0.068) cmH2O s l-1 per 1 cmH2O-1 s l-1 increase in baseline Xrs (P < 0.001). After correcting for baseline reactance, the change in reactance after recruitment was significantly lower for sustained inflation compared with repeated inflation by mean (standard error) 0.25 (0.101) cmH2O (P = 0.0166).

Conclusion: Although there was no significant difference between airway devices, this study demonstrated more effective recruitment via repeated inflations than sustained inflation in anaesthetised children.

Abstract
The 7th National Audit Project (NAP7) of the Royal College of Anaesthetists studied complications of the airway and respiratory system during anaesthesia care including peri-operative cardiac arrest. Among 24,721 surveyed cases, airway and respiratory complications occurred commonly (n = 421 and n = 264, respectively). The most common airway complications were: laryngospasm (157, 37%); airway failure (125, 30%); and aspiration (27, 6%). Emergency front of neck airway was rare (1 in 8370, 95%CI 1 in 2296-30,519). The most common respiratory complications were: severe ventilation difficulty (97, 37%); hyper/hypocapnia (63, 24%); and hypoxaemia (62, 23%). Among 881 reports to NAP7 and 358 deaths, airway and respiratory complications accounted for 113 (13%) peri-operative cardiac arrests and 32 (9%) deaths, with hypoxaemia as the most common primary cause. Airway and respiratory cases had higher and lower survival rates than other causes of cardiac arrest, respectively. Patients with obesity, young children (particularly infants) and out-of-hours care were overrepresented in reports. There were six cases of unrecognised oesophageal intubation with three resulting in cardiac arrest. Of these cases, failure to correctly interpret capnography was a recurrent theme. Cases of emergency front of neck airway (6, approximately 1 in 450,000) and pulmonary aspiration (11, approximately 1 in 25,000) leading to cardiac arrest were rare. Overall, these data, while distinct from the 4th National Audit Project, suggest that airway management is likely to have become safer in the last decade, despite the surgical population having become more challenging for anaesthetists.

Keywords: airway; anaesthesia; cardiac arrest; complications; respiratory.

Resuscitation is a monthly international and interdisciplinary medical journal. The papers published deal with the aetiology, pathophysiology and prevention of cardiac arrest, resuscitation training, clinical resuscitation, and experimental resuscitation research, although papers relating to animal studies will be published only if they are of exceptional interest and related directly to clinical cardiopulmonary resuscitation. Papers relating to trauma are published occasionally but the majority of these concern traumatic cardiac arrest.

Resuscitation Plus, a companion title to the respected Resuscitation, is an open access quarterly international and interdisciplinary medical journal. The papers published deal with the aetiology, pathophysiology and prevention of cardiac arrest, resuscitation training and simulation, clinical resuscitation, and experimental resuscitation research. Animal studies relating to cardiopulmonary resuscitation and post-resuscitation and papers relating to traumatic cardiac arrest and haemorrhagic shock are encouraged. Systematic reviews, narrative reviews, scoping reviews, case reports and methods papers relating to cardiopulmonary resuscitation are also encouraged.

Critical Care and Resuscitation (CC&R) is the official scientific journal of the College of Intensive Care Medicine (CICM). The Journal is a quarterly publication (ISSN 1441-2772) with original articles of scientific and clinical interest in the specialities of Critical Care, Intensive Care, Anaesthesia, Emergency Medicine and related disciplines.

Respiratory Research publishes high-quality clinical and basic research, review and commentary articles on all aspects of respiratory medicine and related diseases.

As the leading fully open access journal in the field, Respiratory Research provides an essential resource for pulmonologists, allergists, immunologists and other physicians, researchers, healthcare workers and medical students with worldwide dissemination of articles resulting in high visibility and generating international discussion.

Topics of specific interest include asthma, chronic obstructive pulmonary disease, cystic fibrosis, genetics, infectious diseases, interstitial lung diseases, lung development, lung tumors, occupational and environmental factors, pulmonary circulation, pulmonary pharmacology and therapeutics, respiratory immunology, respiratory physiology, and sleep-related respiratory problems.

The primary topics of interest in Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (SJTREM) are the pre-hospital and early in-hospital diagnostic and therapeutic aspects of emergency medicine, trauma, and resuscitation. Contributions focusing on dispatch, major incidents, etiology, pathophysiology, rehabilitation, epidemiology, prevention, education, training, implementation, work environment, as well as ethical and socio-economic aspects may also be assessed for publication.