Perioperative medicine training resources: U4M8: Management of complications in the recovery period

ABSTRACT: Hypoglycemia is a condition that occurs when a patient’s blood glucose reaches dangerous levels below 70 mg/dL. Severe hypoglycemia is a medical emergency, and it is important for patients with diabetes and their close contacts—including pharmacists and other healthcare providers—to recognize symptoms of hypoglycemia and proceed with proper treatment. Established guidelines and protocols should be followed based on the severity of the hypoglycemic event. Pharmacists can help reduce a patient’s risk for hypoglycemia, as well as ensure the condition’s proper recognition and treatment, should it occur.

Hypoglycemia is defined as a blood glucose (BG) level ≤70 mg/dL. However, not all patients with a level ≤70 mg/dL have symptoms. Conversely, some patients (especially those with long-standing, poorly controlled diabetes) may experience hypoglycemic symptoms at higher BG levels. Therefore, the term clinical hypoglycemia refers to a plasma glucose concentration that is sufficiently low to cause signs and/or symptoms.

Abstract
Background: Perioperative shivering is a common problem faced in anesthesia practice. Unless it is properly managed and prevented, it causes discomfort and devastating problems, especially in patients with cardiorespiratory problems. Surgery, anesthesia, exposure of skin in a cool operating theater, and administration of unwarmed fluids are some of the major causes for the development of shivering among surgical patients. Currently, a variety of non-pharmacological and pharmacological techniques are available to prevent and manage this problem. The available options to prevent and treat shivering include but are not limited to pre-warming the patient for 15 minutes before anesthesia administration, administration of low dose ketamine, dexamethasone, pethidine, clonidine, dexmedetomidine, tramadol, and magnesium sulfate.

Objective: To develop evidence-based recommendations for the prevention and management of shivering after spinal anesthesia in a resource-limited settings.

Methods: The kinds of literature are searched from Google Scholar, PubMed, Cochrane library, and HINARI databases to get access to current and update evidence on the prevention and management of shivering after spinal anesthesia. The keywords for the literature search were (shivering or prevention) AND (shivering or management) AND (anesthesia or shivering).

Conclusion: Pre-warming the patient with cotton, blanket, gown warming, and administering warm IV fluid 15 minutes before spinal anesthesia are possible non-pharmacologic options for the prevention of shivering. Furthermore, pharmacological medications like low dose ketamine, dexamethasone, magnesium sulfate, ad tramadol can be used as alternative options for the prevention and management strategies for shivering of different degrees in resource-limited areas.

Abstract
Objective: There has been increased interest in the use of low-dose ketamine (LDK) as an alternative analgesic for the management of acute pain in the emergency department (ED). The objective of this systematic review was to compare the analgesic effectiveness and safety profile of LDK and morphine for acute pain management in the ED.

Methods: Electronic searches of Medline and EMBASE were conducted and reference lists were hand-searched. Randomized controlled trials (RCTs) comparing LDK to morphine for acute pain control in the ED were included. Two reviewers independently screened abstracts, assessed quality of the studies, and extracted data. Data were pooled using random-effects models and reported as mean differences and risk ratios (RRs) with 95% confidence intervals (CIs). We used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty of the evidence.

Results: Eight RCTs were included with a total of 1,191 patients (LDK = 598, morphine = 593). There was no significant difference in reported mean pain scores between LDK and morphine within the first 60 minutes after analgesia administration and a slight difference in pain scores favoring morphine at 60 to 120 minutes. The need for rescue medication was also similar between groups (RR = 1.26, 95% CI = 0.50 to 3.16), as was the proportion of patients who experienced nausea (RR = 0.97, 95% CI = 0.63 to 1.49) and hypoxia (RR = 0.38, 95% CI = 0.10 to 1.41). All outcomes were judged to have low certainty in the evidence.

Conclusion: Low-dose ketamine and morphine had similar analgesic effectiveness within 60 minutes of administration with comparable safety profiles, suggesting that LDK is an effective alternative analgesic for acute pain control in the ED.

Abstract
Postoperative nausea and vomiting is a major concern for patients undergoing outpatient surgery under general anaesthesia, and may complicate and delay discharge from hospital. This paper evaluates the safety and efficacy of ondansetron, a 5-HT3 receptor antagonist, in the treatment of postoperative nausea and vomiting. One thousand patients in 30 centres in the United States who received general anaesthesia and developed postoperative nausea and vomiting were studied. In a randomised, double-blind, stratified and parallel designed protocol, patients received either ondansetron 1, 4, 8 mg or placebo for nausea or vomiting occurring within 2 h of entry into the Post Anaesthesia Care Unit. Subsequent episodes of vomiting, nausea scores, laboratory and clinical safety data and adverse events were evaluated during the 24-h study period. In a separate study, pharmacokinetic data were compared for intramuscularly and intravenously administered ondansetron. Each dose of ondansetron was significantly better than placebo in reducing nausea from control values during the initial 2-h study period, and in preventing further emesis over 24 h. There were no significant differences in the incidence of adverse events, changes in laboratory values or measures of vital signs in the ondansetron groups compared to the placebo group. Dose comparisons between the three treatment groups showed that ondansetron 4 mg is the optimal dose to treat postoperative nausea and vomiting. Ondansetron is a well tolerated, efficacious antiemetic which has a similar side effect profile to placebo. Intramuscular administration has the same systemic availability as intravenous administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract
Background: This study was designed to evaluate transcutaneous electrical acupoint stimulation (acustimulation) using the ReliefBand compared with ondansetron for the treatment of established postoperative nausea and vomiting (PONV) after outpatient laparoscopic surgery.

Methods: After the authors obtained institutional review board approval and written informed consent, 268 outpatients were enrolled in this randomized, double-blind, placebo- and sham-controlled study. All patients received antiemetic prophylaxis with metoclopramide, 10 mg intravenously, or droperidol, 0.625 mg intravenously, after induction of anesthesia. A total of 90 patients developed PONV in the recovery units and were randomized to one of three treatment groups: (1) the ondansetron group received 4 mg intravenous ondansetron and a sham ReliefBand; (2) the acustimulation group received 2 ml intravenous saline and a ReliefBand; and (3) the combination group received 4 mg intravenous ondansetron and a ReliefBand. A rescue antiemetic (10 mg intravenous metoclopramide) was administered only if the PONV symptoms persisted for 15 min or longer after initiating the treatment. A blinded observer recorded the recovery times, emetic symptoms, rescue antiemetics, maximum nausea scores, complete response to study treatment, and time to achieve discharge criteria. Postdischarge side effects, as well as patient satisfaction and quality of recovery scores, were assessed at 24 and 72 h after surgery.

Results: The combination group had a significantly higher complete response rate than the acustimulation group (73% vs.40%, P <0.01). In addition, fewer patients (8 vs. 18) in the combination (vs. acustimulation) group experienced subsequent emetic events (P < 0.03). However, there were no significant differences between the three groups with respect to patient satisfaction and quality of recovery scores.

Conclusions: Acustimulation with the ReliefBand can be used as an alternative to ondansetron for the treatment of established PONV. However, the use of ondansetron (4 mg intravenously) in combination with the ReliefBand device improved the complete response rate to the acustimulation therapy.

Abstract
Background: Dexamethasone is widely used for the prevention of postoperative nausea and vomiting (PONV) but little is known about its efficacy for the treatment of established PONV.

Objective: To test the antiemetic efficacy of intravenous dexamethasone for the treatment of established PONV in adults undergoing surgery under general anaesthesia and to determine whether there is dose-responsiveness.

Design: The DexPonv trial is a multicentre, placebo-controlled, randomised, double-blind, dose-finding study. Inclusion of patients was between September 2012 and November 2017. Follow-up for PONV symptoms was for 24 h. Thirty days postoperatively, patients were contacted by study nurses for any information on postoperative bleeding and infection.

Setting: Four public hospitals in Switzerland.

Patients: A total of 803 adults scheduled for elective surgery without any antiemetic prophylaxis signed the consent form; 714 were included. Among those, 319 had PONV and 281 patients were eventually randomised (intention to treat population and safety set). The per protocol set consisted of 260 patients.

Interventions: Patients with PONV symptoms (including retching) were randomised to a single intravenous dose of dexamethasone 3, 6 or 12 mg or matching placebo.

Main outcome measures: The primary endpoint was the absence of further nausea or vomiting (including retching), within 24 h after administration of the study drug.

Results: Dexamethasone was ineffective during the first 24 h, whatever the dosage, compared to placebo, even when the model was adjusted for known risk factors (P = 0.170). There were no differences in the time to treatment failure or the quality of sleep during the first night. There was a positive correlation between the dose of dexamethasone and blood glucose concentrations (P < 0.001), but not with bleeding risk, wound infections or other adverse effects.

Conclusion: This randomised trial failed to show anti-emetic efficacy of any of the tested intravenous regimens of dexamethasone for the treatment of established PONV in adults undergoing surgery under general anaesthesia.

Abstract
Intravenous lidocaine is used widely for its effect on postoperative pain and recovery but it can be, and has been, fatal when used inappropriately and incorrectly. The risk-benefit ratio of i.v. lidocaine varies with type of surgery and with patient factors such as comorbidity (including pre-existing chronic pain). This consensus statement aims to address three questions. First, does i.v. lidocaine effectively reduce postoperative pain and facilitate recovery? Second, is i.v. lidocaine safe? Third, does the fact that i.v. lidocaine is not licensed for this indication affect its use? We suggest that i.v. lidocaine should be regarded as a 'high-risk' medicine. Individual anaesthetists may feel that, in selected patients, i.v. lidocaine may be beneficial as part of a multimodal peri-operative pain management strategy. This approach should be approved by hospital medication governance systems, and the individual clinical decision should be made with properly informed consent from the patient concerned. If i.v. lidocaine is used, we recommend an initial dose of no more than 1.5 mg.kg-1 , calculated using the patient's ideal body weight and given as an infusion over 10 min. Thereafter, an infusion of no more than 1.5 mg.kg-1 .h-1 for no longer than 24 h is recommended, subject to review and re-assessment. Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions. This includes not starting i.v. lidocaine within 4 h after any nerve block, and not performing any nerve block until 4 h after discontinuing an i.v. lidocaine infusion.

Abstract
Background: The role of propofol for the management of postoperative nausea and vomiting (PONV) is not well established. This study determines the efficacy of small doses of propofol administered by patient-controlled device for the treatment of PONV.

Methods: Patients presenting for ambulatory surgery received a standardized general anesthetic. Those who experienced significant nausea or emesis within 1 h of arrival in the recovery room were randomized to receive repeated doses of propofol 20 mg (P-20), propofol 40 mg (P-40), or intralipid (placebo) on demand. Study medications (in equal volumes) were administered with a patient-controlled delivery device for 2 h. A lockout interval of 5 min between doses was used. The following parameters were assessed: nausea, vomiting, rescue antiemetic use, recovery profile, study drug administration history, and satisfaction with treatment.

Results: Sixty-nine patients participated in the study. Patient demographics were similar. The average nausea score for a patient in the P-20 and P-40 groups was 25% and 29% less, respectively, compared with placebo during the study period (P < 0.05). This difference was apparent 15 min after initiation of therapy. More placebo patients vomited (P-20, 12%; P-40, 23%; placebo, 56%; P = 0.003) and needed rescue antiemetics (P-20, 17%; P-40, 23%; placebo, 70%; P = 0.001) compared with treatment groups. Sedation scores were similar between groups. Propofol-treated patients had shorter stays in the post-anesthesia care unit (PACU; P-20, 131+/-35 min [mean +/- SD]; P-40, 141+/-34 min; placebo, 191+/-92 min; P = 0.005) and higher satisfaction with their control of PONV than placebo (P < 0.01).

Conclusions: Propofol is effective in managing PONV with shorter PACU stay and great degree of patient satisfaction. There were two episodes of oversedation in the P-40 group. Hence, propofol at a demand dose of 20 mg seems more appropriate.

Abstract
Study objectives: To compare the effectiveness of treating established postoperative nausea and vomiting (PONV) with an antiemetic acting at a different receptor with that of treating PONV with the antiemetic used for prophylaxis.

Design: Analysis of data collected in a previously published randomized, double-blind, placebo-controlled study.

Setting: Outpatient surgical procedures from 50 institutions in North America.

Patients: Patients (N = 2061) undergoing outpatient surgical procedures planned to last no more than 2 hours.

Interventions: Patients were randomized to receive ondansetron 4 mg, droperidol 1.25, droperidol 0.625 mg, or placebo. In the postoperative anesthesia care unit, patients who developed PONV received rescue antiemetics at the discretion of the attending anesthesiologist. The following antiemetics were used for rescue: ondansetron 4 mg, droperidol 0.625 to 1.25 mg, metoclopramide 10 mg, promethazine 6.25 to 25 mg, and dimenhydrinate 25 to 50 mg.

Measurements: The complete response rate (no nausea, no emesis, and no need for further rescue) after administration of the rescue antiemetic in patients with established PONV was calculated. The complete response rate after administration of each of the different rescue antiemetics was compared with that after administration of the same antiemetic used for PONV prophylaxis.

Main results: In patients who failed prophylaxis with ondansetron 4 mg, the complete response rate was significantly higher (P = .02) after rescue with promethazine 6.25 to 25 mg (78%) than after rescue with ondansetron 4 mg (46%). In patients who failed prophylaxis with droperidol 0.625 and 1.25 mg, the complete response rate was significantly higher after rescue with promethazine 6.25 to 25 mg (77%; P = .02) and dimenhydrinate 25 to 50 mg (78%; P = .04) than after rescue with droperidol 0.625 to 1.25 mg (56%).

Conclusion: In patients who failed prophylaxis with ondansetron or droperidol, promethazine was significantly more effective than the agent used for prophylaxis for the treatment of PONV. In patients who failed prophylaxis with droperidol, dimenhydrinate was also more effective than droperidol for the treatment of established PONV in the postoperative anesthesia care unit.

Abstract
Introduction: Post-operative nausea and vomiting (PONV) are a common post-operative problem in anesthesia. The incidence of PONV in patients undergoing cesarean sections is very high. Post-operative nausea and vomiting have many negative impacts on the patient, baby, family, and health care system. Therefore, appropriate evidence-based knowledge regarding the prevention and management of PONV for those high-risk patients is a timely and very important issue to address to decrease the associated complications.

Methods: A comprehensive literature search was conducted in Pubmed/Medline, Cochrane reviews, and google scholar including those studies published in the English language from 2010 up to 2021. The methodological quality of the included studies was appraised by the Cochrane risk of a biased assessment tool for intervention and non-interventional studies.

Result: The search strategy identified a total of 10,540 articles from different electronic databases. 33 articles were selected for screening after duplicates were removed; finally, 17 articles were included for critical appraisal and 16 articles were excluded with reasons. The included articles consist of 15 RCT, 1 non-control prospective cohort, and 1 cross-sectional study.

Conclusion: Pieces of evidence revealed that all obstetrics patients undergoing cesarean section should be given multimodal PONV prophylaxis. It is shown that a multimodal approach by a combination of different antiemetic agents should be preferred and most effective in preventing intraoperative and postoperative nausea and vomiting for patients undergoing cesarean section because of the complex pathophysiology of nausea and vomiting.

Abstract
The anti-nauseant efficacy of low-dose propofol was investigated in a blinded, randomized trial. Patients who complained of nausea and/or vomiting following laparoscopic gynaecological surgery and who requested antiemetic were randomly assigned to receive placebo, propofol 3 mg, propofol 9 mg or propofol 27 mg by intravenous injection. Nausea, vomiting and sedation were recorded by a blinded observer for 90 minutes following administration of the test drug, prior to discharge, and 24 hours following surgery. Rescue antiemetic (droperidol 1.0 mg i.v.) was available from 10 minutes after administration of test drug. Propofol failed to reduce nausea scores and did not reduce the incidence of vomiting. Numbers of patients receiving rescue antiemetic were similar in the four treatment groups. In the first 10 minutes following test drug administration, sedation scores were increased by propofol in a dose-related manner. We conclude that, in the dose range studied, propofol is ineffective for the treatment of nausea and vomiting occurring soon after laparoscopic gynaecological surgery.

Abstract
Acute pain management is a challenging area encountered by inpatient clinicians every day. While patient care is increasingly complex and costly in this realm, the availability of applicable specialists is waning. This narrative review seeks to support diverse hospital-based healthcare providers in refining and updating their acute pain management knowledge base through clinical pearls and point-of-care resources. Practical guidance is provided for the design and adjustment of inpatient multimodal analgesic regimens, including conventional and burgeoning non-opioid and opioid therapies. The importance of customized care plans for patients with preexisting opioid tolerance, chronic pain, or opioid use disorder is emphasized, and current recommendations for inpatient management of associated chronic therapies are discussed. References to best available guidelines and literature are offered for further exploration. Improved clinician attention and more developed skill sets related to acute pain management could significantly benefit hospitalized patient outcomes and healthcare resource utilization.

Abstract
Cognition is defined as the brain's ability to acquire, process, store, and retrieve information. Pain has been described as an unpleasant sensory or emotional experience, and for experiencing pain consciously, cognitive processing becomes imperative. Moreover, evaluation of pain strongly depends on cognition as it requires learning and recall of previous experiences. There could be a possible close link between neural systems involved in cognition and pain processing, and studies have reported an association between pain and cognitive impairment. In this narrative review, we explore the available evidence that has investigated cognitive changes associated with pain. We also examine the anatomical, biochemical, and molecular association of pain and neuro-cognition. Additionally, we focus on the cognitive impairment caused by analgesic medications. There is a need to improve our understanding of pathophysiology and cognitive impairment mechanisms associated with chronic pain and its treatment. This area provides a diverse opportunity for grounding future research, aiding institution of timely interventions to prevent chronic pain and associated cognitive decline, ultimately improving patient care.

Abstract
Background: The dose of intrathecal morphine is important because of its narrow therapeutic range. Due to a compounding error, pharmacy-compounded, ready-to-use syringes contained 1 mg ml-1 morphine instead of the intended 50 mcg ml-1. Six patients consequently received this twenty-fold dose. This study aims to describe the serious adverse events in these six patients and a systematic review is added to describe the characteristics of serious adverse events after intrathecal morphine.

Methods: A retrospective case series described all six patients that received the erroneous morphine intrathecally for analgesia after laparoscopic segmental colonic resections. The patients' charts were reviewed for the occurrence, timing, duration and management of adverse events, the vital signs at the night after surgery, and length of hospital stay. A systematic review investigated characteristics of serious adverse events after intrathecal morphine in a perioperative setting.

Results: Four patients had a serious adverse event, which was respiratory depression combined with somnolence (n = 3) and hypotension (n = 1). The review yielded 63 cases with serious adverse events, predominantly somnolence and/or respiratory depression. The onset occurred between 2 and 24 hours after injection. The severity of symptoms varied and life-threatening respiratory depression only occurred after a dose >900 mcg or when potentiating medication was used. Naloxone did not affect analgesia. No prolonged sequalae occurred.

Conclusion: This study reveals that respiratory depression and somnolence are the predominant serious adverse events after intrathecal morphine in a perioperative setting and demonstrated a large variation in the presentation of symptoms.

Abstract
Purpose: To compare the efficacy of propofol in a subhypnotic dose (10 mg iv), droperidol (1.25 mg iv), or metoclopramide (10 mg iv) in the treatment of PONV in the post anaesthesia care unit (PACU).

Methods: In a prospective, randomized, double-blind protocol, over four months, all eligible inpatients and outpatients were asked to give their consent to be included in the study should they suffer PONV in the PACU. They received a standardized general anaesthetic without any prophylactic antiemetic drug. In the recovery room, patients complaining of persistent nausea (lasting more than ten minutes) and/or experiencing at least two episodes of retching or vomiting were given one of the three study drugs. Recurrence of retching or vomiting was recorded for 60 min after administration of the study drug and nausea severity was assessed on a visual analog scale. Patients still complaining of PONV 30 min after administration of the study drug received a rescue medication (dimenhydrinate).

Results: Seventy-eight patients received one of the study drugs. The recurrence of retching or vomiting was higher with propofol (58%) than with droperidol (4%) or metoclopramide (24%) (P < 0.001). More patients who received propofol needed the rescue medication (54%) than those who received droperidol (15%) or metoclopramide (28%) (P < 0.02). No difference was observed in nausea severity.

Conclusion: A subhypnotic dose of propofol (10 mg iv) is less effective than the conventional antiemetic drugs droperidol and metoclopramide for the treatment of PONV in the PACU.

Abstract
Postoperative shivering is a common complication of anaesthesia. Shivering is believed to increase oxygen consumption, increase the risk of hypoxemia, induce lactic acidosis, and catecholamine release. Therefore, it might increase the postoperative complications especially in high-risk patients. Moreover, shivering is one of the leading causes of discomfort for postsurgical patients. Shivering is usually triggered by hypothermia. However, it occurs even in normothermic patients during the perioperative period. The aetiology of shivering has been understood insufficiently. Another potential mechanism is pain and acute opioid withdrawal (especially with the use of short-acting narcotics). Besides that shivering is poorly understood, the gold standard for the treatment and prevention has not been defined yet. Perioperative hypothermia prevention is the first method to avoid shivering. Many therapeutic strategies for treating shivering exist and most are empiric. Unfortunately, the overall quality of the antishivering guidelines is low. Two main strategies are available: pharmacological and non-pharmacological antishivering methods. The combination of forced-air warming devices and intravenous meperidine is the most validated method. We also analysed different medications but final conclusion about the optimal antishivering medication is difficult to be drawn due to the lack of high-quality evidence. Nevertheless, control of PS is possible and clinically effective with simple pharmacological interventions combined with non pharmacological methods. However, to be consistent with the most up-to-date, evidence-based practice, future antishivering treatment protocols should optimize methodological rigor and transparency.

Abstract
Background: Dexamethasone is useful as prophylaxis for postoperative nausea and vomiting (PONV).

Aim: To study the short term efficacy of dexamethasone to treat PONV in adults without prophylaxis, and compare its efficacy with that of droperidol and ondansetron.

Material and methods: A prospective study was performed with 120 consecutive adult patients presenting PONV in the postanesthesia care unit (PACU) at a University teaching hospital. During the occurrence of PONV, patients were randomized to receive in a double blind manner dexamethasone 8 mg IV (Group 1, n=40), droperidol 1.25 mg IV (Group 2, n=40), or ondansetron 2 mg IV (Group 3, n=40). Risk factors for PONV were recorded. Evaluations were made until discharge from the PACU and included presence of PONV, degree of sedation, and other potential adverse effects of the study drugs. Short term efficacy was defined as the percentage of patients free of PONV during all the stay in PACU after treatment.

Results: General data was similar for the 3 groups. Mean +/- SD stay in PACU after treatment was 101+/-34 minutes in Group 1, 93+/-33 minutes in Group 2, and 99+/-32 minutes in Group 3 (NS). Short term efficacy (CI 95%) was 55% (40-70%) in Group 1, 90% (81-99%) in Group 2, and 63% (48-78%) in Group 3 (p <0.05 for group 2 vs 1 and 3). There were no adverse effects attributable to the study drugs.

Conclusions: Short term efficacy of dexamethasone to treat PONV was similar to ondansetron, but inferior to droperidol. Further studies are needed to define the duration of this effect of dexamethasone.

Abstract
Background: The 100 mm visual analog scale (VAS) score is widely used to measure pain intensity after surgery. Despite this widespread use, it is unclear what constitutes the minimal clinically important difference (MCID); that is, what minimal change in score would indicate a meaningful change in a patient's pain status.

Methods: We enrolled a sequential, unselected cohort of patients recovering from surgery and used a VAS to quantify pain intensity. We compared changes in the VAS with a global rating-of-change questionnaire using an anchor-based method and three distribution-based methods (0.3 sd , standard error of the measurement, and 5% range). We then averaged the change estimates to determine the MCID for the pain VAS. The patient acceptable symptom state (PASS) was defined as the 25th centile of the VAS corresponding to a positive patient response to having made a good recovery from surgery.

Results: We enrolled 224 patients at the first postoperative visit, and 219 of these were available for a second interview. The VAS scores improved significantly between the first two interviews. Triangulation of distribution and anchor-based methods resulted in an MCID of 9.9 for the pain VAS, and a PASS of 33.

Conclusions: Analgesic interventions that provide a change of 10 for the 100 mm pain VAS signify a clinically important improvement or deterioration, and a VAS of 33 or less signifies acceptable pain control (i.e. a responder), after surgery.

Abstract
The goal of this study was to determine whether recovery room monitoring of bladder volume would affect patient outcome after ambulatory surgery. Incidence of urinary retention and times to void and to discharge were compared in 161 patients managed with ultrasound bladder monitoring versus 173 controls without bladder monitoring. Urinary retention was diagnosed by clinical means or by ultrasound, confirmed by bladder catheterization. Patients were required to void or were catheterized before discharge. In the control patients without underlying risk factors for retention, median time to void was 95 min, and retention occurred in 0.8%, which was not significantly different from the ultrasound group (80 min and 0%, respectively). After hernia/anal surgery or spinal/epidural anesthesia, voiding was delayed (130 and 213 min), incidence of retention was increased (17% and 13%), and there was a trend toward earlier voiding (168+/-99 vs. 138+/-68 min) with bladder monitoring. We conclude that most patients at low risk of retention void within 3 h of outpatient surgery; their outcome is unaffected by bladder monitoring. After hernia/anal surgery and spinal/ epidural anesthesia, the likelihood of urinary retention is increased, and ultrasound monitoring facilitates deciding whether such patients should be catheterized.

Implications: Incidence of bladder catheterization and urinary retention were compared in patients managed with and without ultrasound monitoring of bladder volume after outpatient surgery. Monitoring did not alter outcome in patients at low risk of retention, but it facilitated determining when to catheterize patients at high risk of retention (hernia/anal surgery, spinal/epidural anesthesia).

Abstract
Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stresses such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:5,000 to 1:50,000-100,000 anesthesias. However, the prevalence of the genetic abnormalities may be as great as one in 3,000 individuals. MH affects humans, certain pig breeds, dogs, horses, and probably other animals. The classic signs of MH include hyperthermia to marked degree, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. Early recognition of the signs of MH, specifically elevation of end-expired carbon dioxide, provides the clinical diagnostic clues. In humans the syndrome is inherited in autosomal dominant pattern, while in pigs in autosomal recessive. The pathophysiologic changes of MH are due to uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation. Due to ATP depletion, the muscle membrane integrity is compromised leading to hyperkalemia and rhabdomyolysis. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 90 mutations have been identified in the RYR-1 gene located on chromosome 19q13.1, and at least 25 are causal for MH. Diagnostic testing relies on assessing the in vitro contracture response of biopsied muscle to halothane, caffeine, and other drugs. Elucidation of the genetic changes has led to the introduction, on a limited basis so far, of genetic testing for susceptibility to MH. As the sensitivity of genetic testing increases, molecular genetics will be used for identifying those at risk with greater frequency. Dantrolene sodium is a specific antagonist of the pathophysiologic changes of MH and should be available wherever general anesthesia is administered. Thanks to the dramatic progress in understanding the clinical manifestation and pathophysiology of the syndrome, the mortality from MH has dropped from over 80% thirty years ago to less than 5%.

Abstract
Background: Postoperative nausea and vomiting following outpatient surgery can significantly delay discharge. This study evaluates the safety and efficacy of ondansetron (a new 5-HT3 antagonist) in the treatment of postoperative nausea and vomiting in patients following outpatient surgery.

Methods: Five hundred outpatient surgical patients (53 male and 447 female), receiving general endotracheal anesthesia, were studied at ten centers. Patients were stratified by gender and received, in a randomized, double-blind manner, 1, 4, or 8 mg ondansetron or placebo in response to nausea and/or vomiting postoperatively. Episodes of vomiting, nausea scores, adverse events, vital signs, and laboratory values were evaluated before and during the 24 h after study drug administration.

Results: Complete response to study medication (no vomiting and/or retching, and no rescue antiemetic over the initial 0-2-h period) was more frequent in the ondansetron groups (1 mg 57%, 4 mg 61%, and 8 mg 57%) than in the placebo group (30%, P < .001). For the 0-24-h study a complete response occurred in only 15% of the placebo group compared to 41%, 47%, and 47% of the 1-, 4-, and 8-mg ondansetron groups, respectively (P < .001 for all comparisons with placebo). Median nausea scores (range 0-10) during the initial observation period (0-2 h) were significantly lower for all doses of ondansetron (1.3, 0.8, 1.8 for 1, 4, and 8 mg, respectively) as compared with placebo (2.3). No significant differences occurred in hemodynamic stability, incidence of adverse events, or changes in laboratory values in the ondansetron groups compared to the placebo group.

Conclusions: Ondansetron, in doses less than 8 mg, is a safe, effective antiemetic for treating postoperative nausea and vomiting.

Abstract
Background: Body temperature is tightly regulated with hormonal and cellular metabolism for normal functioning; however perioperative hypothermia is common secondary to anesthesia and surgical exposure.Prevention and maintaining body temperature should be started 1-2hrs before induction of anesthesia, to do this both active and passive warming system are effective to prevent complications associated with perioperative hypothermia.

Methods: The aim of this systematic review is to develop a clear clinical practice protocol in prevention and management of perioperative hypothermia for elective adult surgical patients.The study is conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline 2020. After formulating clear criteria for the evidences to be included an appropriate method of searching was conducted by using the Pub Med, Google scholar and Cochrane library using the following MeSH terms: (inadvertent hypothermia AND anesthesia, hypothermia AND perioperative management and thermoregulation AND anesthesia) were used to draw evidences.After a reasonable amount of evidences were collected, appraisal and evaluation of study quality was based on WHO 2011 level of evidence and degree of recommendation. Final conclusions and recommendations are done by balancing the benefits and downsides of alternative management strategies for perioperative management of hypothermia.This systematic review registered with research registry unique identifying number (UIN) of "reviewregistry1253" in addition the overall AMSTAR 2 quality of this systematic review is moderate level.

Discussion: Preserving a patient's body temperature during anesthesia and surgery is to minimize heat loss by reducing radiation and convection from the skin, evaporation from exposed surgical areas, and cooling caused by the introduction of cold intravenous fluids.

Conclusion: Hypothermia is least monitored complication during anesthesia and surgery results cardiac abnormalities, impaired wound healing, increased surgical site infections, shivering and delayed postoperative recovery, and coagulopathies.

Abstract
To compare the efficacy in the treatment of post-operative nausea and/or vomiting (PONV), 75 patients undergoing gynaecological procedures under general anaesthesia using N2O/enflurane who suffered from PONV in the first hour after surgery were randomly allocated to three groups containing 25 patients each to receive either alizapride 100 mg, droperidol 1 mg or ondansetron 8 mg (i.v.). Patients expressed the severity of their nausea on a Visual Analogue Scale (VAS) ranging from 0 (none) to 10 (as bad as possible). Vomiting was recorded as present or absent, and the number of emetic events was noted. Data were recorded until rescue medication was given or until 4 h after the administration of the study drug. There were no significant differences between the three groups in the average VAS scores and the presence of vomiting at the time of entry into the study. Fifteen and 30 min after the administration of the study drug, VAS decreased notably in all groups. This decreases was similar and statistically significant within each group. However, comparison between the three groups showed no statistically significant differences. There was no statistically significant difference between the three groups in the number of patients receiving rescue medication, the number of emetic events and the time from administration of the study drug until rescue medication was given. It is concluded that alizapride 100 mg, droperidol 1 mg and ondansetron 8 mg intravenously are equally effective in the treatment of PONV after gynaecological procedures and that the newer drugs alizapride and ondansetron offer no advantage over droperidol.

Abstract
Background
Postoperative nausea and vomiting is one of the common dissatisfying after surgery with a wide range of complications. It has an incidence of about 80% for patients with multiple risk factors. The etiologies of PONV are multifactorial including patient, anesthetic, and surgical factors. This review aims to support the clinical decision making of PONV management based on available evidence.
Methods
Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol was used to conduct this study. PubMed, Cochrane library, and Google Scholar search engines were used to find evidence that helps to draw recommendations and conclusions.
Results
In this systemic review and guideline we had used five systemic review and Meta-analysis, one guideline and 4 Meta-analysis of RCTs, three Literature reviews, three Multicenter RCTs, thirteen Single-center RCTs, and two Cross-sectional studies with their respective description of studies.
Discussion
In the presence of persistent nausea and vomiting, possible contributing factors, such as patient-controlled morphine analgesia, presence of blood in the pharynx, or an abdominal obstruction, hypotension, hypoxia should be excluded before rescue therapy may be initiated.
Conclusions
Patients who came for surgery have to be evaluated for the risk factors PONV and they should be categorized as low or high risk of it based on the APFEL risk score. Prevention and management of PONV should follow the flow chart as evidenced by most of the literature.

Abstract
Recognising the importance of the prevention and early treatment of postoperative nausea and vomiting (PONV) is essential to avoid postoperative complications, improve patient satisfaction and enable the development of major outpatient surgery and fast-track surgery. The topic of PONV might seem to have become stagnant, but we are moving forward. New concepts and problems like post-discharge nausea and vomiting, new risk factors and new drugs are appearing. However, there continue to be mistaken notions about PONV, such as the association between PONV and post-anaesthesia care unit stays, or assuming that it is a risk factore characteristic of the patient, anaesthesia or surgery when it is not. Perhaps, now is the moment to tackle PONV in a different manner, implementing guidelines and going for more aggressive prophylaxis in some groups of patients. We present an extensive review of this topic.

Keywords: Antiemetics; Antieméticos; Emesis; Escala de riesgo; Factores de riesgo; Náuseas y vómitos postoperatorios; Postoperative nausea and vomiting; Risk factors; Risk score.