The antiemetic effect of lorazepam after outpatient strabismus surgery in children

WITHDRAWN: Drugs for preventing postoperative nausea and vomiting

BACKGROUND

Drugs can prevent postoperative nausea and vomiting, but their relative efficacies and side effects have not been compared within one systematic review.

OBJECTIVES

The objective of this review was to assess the prevention of postoperative nausea and vomiting by drugs and the development of any side effects.

SEARCH METHODS

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2004), MEDLINE (January 1966 to May 2004), EMBASE (January 1985 to May 2004), CINAHL (1982 to May 2004), AMED (1985 to May 2004), SIGLE (to May 2004), ISI WOS (to May 2004), LILAC (to May 2004) and INGENTA bibliographies.

SELECTION CRITERIA

We included randomized controlled trials that compared a drug with placebo or another drug, or compared doses or timing of administration, that reported postoperative nausea or vomiting as an outcome.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted outcome data.

MAIN RESULTS

We included 737 studies involving 103,237 people. Compared to placebo, eight drugs prevented postoperative nausea and vomiting: droperidol, metoclopramide, ondansetron, tropisetron, dolasetron, dexamethasone, cyclizine and granisetron. Publication bias makes evidence for differences among these drugs unreliable. The relative risks (RR) versus placebo varied between 0.60 and 0.80, depending upon the drug and outcome. Evidence for side effects was sparse: droperidol was sedative (RR 1.32) and headache was more common after ondansetron (RR 1.16).

AUTHORS' CONCLUSIONS

Either nausea or vomiting is reported to affect, at most, 80 out of 100 people after surgery. If all 100 of these people are given one of the listed drugs, about 28 would benefit and 72 would not. Nausea and vomiting are usually less common and, therefore, drugs are less useful. For 100 people, of whom 30 would vomit or feel sick after surgery if given placebo, 10 people would benefit from a drug and 90 would not. Between one to five patients out of every 100 people may experience a mild side effect, such as sedation or headache, when given an antiemetic drug. Collaborative research should focus on determining whether antiemetic drugs cause more severe, probably rare, side effects. Further comparison of the antiemetic effect of one drug versus another is not a research priority.

The effect of triazolam premedication on anxiety, sedation, and amnesia in general anesthesia

BACKGROUND

Benzodiazepines have been used preoperatively as part of an anesthesia regimen to attenuate the anxiety of patients. In this study, we aimed to examine the effect of oral triazolam, a short-acting benzodiazepine, on anxiety, sedation, and amnesia.

METHODS

Ninety patients, aged 20-55 years, were randomly assigned to receive no premedication, or to receive triazolam 0.25 mg or 0.375 mg 1 h before anesthesia. Anxiety score, sedation score, blood pressure, heart rate and psychomotor performance were measured on the evening before surgery and on the day of surgery. Additional tests of psychomotor performance were performed in the postanesthesia care unit and on the next day of surgery. The occurrence of amnesia, bispectral index (BIS), recovery profiles and patient satisfaction with overall anesthesia care were also evaluated.

RESULTS

Changes in the anxiety and sedation scores on the day of surgery were not significantly different among groups, whereas the increases in systolic blood pressure and heart rate were significantly less in both triazolam groups. The triazolam groups both showed a higher incidence of high satisfaction scores (≥ 2). The two triazolam groups also showed similar outcomes, except for a dose-dependent increase in the number of patients with amnesia and BIS values < 90. Delayed recovery from general anesthesia and psychomotor impairment were not observed in the triazolam groups.

CONCLUSIONS

Triazolam 0.25 mg or 0.375 mg reduced the hemodynamic changes associated with anxiety, produced potent amnesia, and improved patient satisfaction. We suggest that triazolam can be used effectively as anesthetic premedication in adults.

Effect of midazolam, dexamethasone and their combination on the prevention of nausea and vomiting following strabismus repair in children

BACKGROUND

Postoperative nausea and vomiting is a common complication following strabismus surgery. This randomized and double-blind study was designed to evaluate the efficacy of midazolam alone or in combination with dexamethasone in reducing the incidence of postoperative nausea and vomiting in children undergoing strabismus repair.

METHODS

One hundred ASA I children, aged 4-12 yr, scheduled to undergo elective strabismus surgery, were enrolled. No premedication was given. Anaesthesia was induced with sevoflurane, nitrous oxide and oxygen. After induction, fentanyl 2 microg kg-1 and cisatracurium 0.1 mg kg-1 were administered and an endotracheal tube was inserted. After induction of anaesthesia and before start of surgery, patients were randomly allocated into one of four groups of 25 children each to receive placebo, midazolam 50 microg kg-1, dexamethasone 0.5 mg kg-1 or a combination of midazolam 50 microg kg-1 and dexamethasone 0.5 mg kg-1. Episodes of nausea, and retching and vomiting were recorded during the first 24 h after surgery.

RESULTS

The incidence of postoperative nausea was 48%, 32%, 12% and 0% with placebo, dexamethasone, midazolam and the midazolam-dexamethasone combination, respectively. The incidence of vomiting was 52% and 32% with placebo and dexamethasone, respectively; no child vomited with midazolam alone, or with the midazolam-dexamethasone combination.

CONCLUSION

Prophylactic midazolam with or without dexamethasone reduces the incidence of PONV in children undergoing strabismus repair.

The use of ketamine or ketamine-midazolam for adenotonsillectomy

BACKGROUND

Ketamine's role in clinical anaesthesia is developing as a result of the evolving concepts of its mechanism of action and the advantages of its alternative routes of administration. In this study, we aimed to investigate the frequency and severity of adverse effects, specifically emergence phenomena and vomiting, when ketamine with or without midazolam used as a sole anaesthetic.

METHODS

One hundred children, aged between 3 and 10 years, scheduled for adenotonsillectomy were studied. Fifty ASA physical status I-II patients were administered ketamine and atropine intramuscularly (group K, n=50). The remaining 50 children were given ketamine, atropine and midazolam by as the same route (group KM, n=50). Noninvasive hemodynamic and oxygenation variables were monitored. Operative conditions and recovery profiles such as hallucinations, nightmares, awakening by crying agitation and retching-vomiting were investigated in 1st, 2nd, 15th, 30th and 60th days after the operation.

RESULTS

A significant reduction in emergence reactions was demonstrated especially in group KM during the early postoperative period (p<0.05). Retching-vomiting also reduced significantly in the group KM during the same time (p<0.05).

CONCLUSION

As a sole anaesthetic ketamine with or without midazolam provided a calm and safe anaesthesia for paediatric patients in short term procedures. In addition, it must be noted that, a better postoperative early period was achieved by ketamine with midazolam.

Drugs for preventing postoperative nausea and vomiting

BACKGROUND

Drugs can prevent postoperative nausea and vomiting, but their relative efficacies and side effects have not been compared within one systematic review.

OBJECTIVES

The objective of this review was to assess the prevention of postoperative nausea and vomiting by drugs and the development of any side effects.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2004), MEDLINE (January 1966 to May 2004), EMBASE (January 1985 to May 2004), CINAHL (1982 to May 2004), AMED (1985 to May 2004), SIGLE (to May 2004), ISI WOS (to May 2004), LILAC (to May 2004) and INGENTA bibliographies.

SELECTION CRITERIA

We included randomized controlled trials that compared a drug with placebo or another drug, or compared doses or timing of administration, that reported postoperative nausea or vomiting as an outcome.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted outcome data.

MAIN RESULTS

We included 737 studies involving 103,237 people. Compared to placebo, eight drugs prevented postoperative nausea and vomiting: droperidol, metoclopramide, ondansetron, tropisetron, dolasetron, dexamethasone, cyclizine and granisetron. Publication bias makes evidence for differences among these drugs unreliable. The relative risks (RR) versus placebo varied between 0.60 and 0.80, depending upon the drug and outcome. Evidence for side effects was sparse: droperidol was sedative (RR 1.32) and headache was more common after ondansetron (RR 1.16).

AUTHORS' CONCLUSIONS

Either nausea or vomiting is reported to affect, at most, 80 out of 100 people after surgery. If all 100 of these people are given one of the listed drugs, about 28 would benefit and 72 would not. Nausea and vomiting are usually less common and, therefore, drugs are less useful. For 100 people, of whom 30 would vomit or feel sick after surgery if given placebo, 10 people would benefit from a drug and 90 would not. Between one to five patients out of every 100 people may experience a mild side effect, such as sedation or headache, when given an antiemetic drug. Collaborative research should focus on determining whether antiemetic drugs cause more severe, probably rare, side effects. Further comparison of the antiemetic effect of one drug versus another is not a research priority.

Postoperative Nausea and Vomiting

Despite many medical advances, the incidence of postoperative nausea and vomiting (PONV) and postdischarge nausea and vomit-ing (PDNV) remains high. Sequelae such as dehydration, wound dehiscence, bleeding and others, contributed to increased healthcare costs and patient dissatisfaction. This article reviews the literature regarding the anatomy of emesis, the predictors of PONV and various treatments.

Evidence-based management of postoperative nausea and vomiting: a review

PURPOSE

To provide evidence-based guidelines for the prophylaxis and treatment of postoperative nausea and vomiting (PONV).

SOURCE

Literature from randomized controlled trials, systematic reviews, logistic regression analyses and expert opinion in the management of PONV.

PRINCIPAL FINDINGS

The etiology of PONV is multifactorial. Patient, anesthesia, and surgery related risk factors have been identified. Universal PONV prophylaxis is not cost-effective. Identification of patients at high-risk of PONV allows targeting prophylaxis to those who will benefit most from it. No prophylaxis is needed for patients at low risk for PONV. For patients at moderate risk for PONV, prophylaxis using a single antiemetic or a combination of two agents should be considered. Double and triple antiemetic combinations should be considered for patients at high risk for PONV. Furthermore, a multimodal approach should be adopted incorporating steps to keep the baseline risk of PONV low. The optimum cost-effective approach to the management of PONV will differ between an ambulatory centre and an inpatient hospital setting. For the treatment of established PONV in patients who failed prophylaxis, patients should not receive a repeat dose of the prophylactic antiemetic. Rather, a drug acting at a different receptor should be used. Beyond six hours after surgery, patients can be treated with any of the agents used for prophylaxis, except dexamethasone and transdermal scopolamine.

CONCLUSION

PONV are common after anesthesia and surgery. We provided evidence-based guidelines for the management of this problem based on the available literature.

Midazolam: An Effective Antiemetic After Cardiac Surgery???A Clinical Trial

Cardiac surgery has been associated with a significant incidence of postoperative nausea and vomiting (PONV). To assess the antiemetic property of midazolam, we undertook this double-blinded, randomized trial in 200 patients undergoing cardiac surgery involving cardiopulmonary bypass, and we compared its efficacy with that of ondansetron in preventing PONV. Assessments on the occurrence of PONV were made at regular intervals for the first 24 h after tracheal extubation, along with sedation and pain scoring. We report a 6% incidence of nausea and no incidence of vomiting in the midazolam group, compared with a 21% incidence of PONV in the ondansetron group (P < 0.001). All 21 patients (18 women and 3 men) in the ondansetron group and none of the 6 patients (all women) in the midazolam group required a rescue antiemetic drug (P < 0.001). The sedation scores and postoperative pain scores were comparable in both groups. We conclude that midazolam, instituted as a continuous infusion in a dose of 0.02 mg. kg(-1). h(-1), is a more effective antiemetic than ondansetron in a dose of 0.1 mg/kg IV every 6 h for the prevention of PONV after cardiac surgery.

Using diazepam and atropine before strabismus surgery to prevent postoperative nausea and vomiting: a randomized, controlled study

OBJECTIVE

To evaluate the efficacy of diazepam and atropine sulfate premedication in preventing nausea and vomiting after strabismus surgery under general anesthesia.

METHODS

Fifty children age 4 to 15 years who underwent strabismus surgery at Cukurova University Medical Faculty, Department of Ophthalmology, from February 2000 to June 2000 were randomized into 2 groups: 25 children in the control group did not receive premedication, whereas 25 children in the treatment group received premedication with 0.15 mg/kg diazepam and 0.015 mg/kg atropine sulfate. Occurrence of postoperative nausea and vomiting (PONV) was recorded.

RESULTS

The incidence of PONV was lower in the premedicated group (P <.018, chi(2) test).

CONCLUSIONS

It is concluded that diazepam and atropine sulfate premedication decreases nausea and vomiting after strabismus surgery.

Management of postoperative nausea and vomiting in children

In spite of improvements in anesthesia techniques, the 'big little problem' of postoperative nausea and vomiting (PONV) still exists. PONV can prolong recovery room stay and hospitalization, and is one of the most common causes of hospital readmission after day surgery. While there is little evidence to support prophylactic administration of antiemetics in patients at low risk of PONV, the higher risk population could benefit from the use of adequate antiemetic drugs. A wide variety of pharmacological approaches have been reported to be effective, as well as some nonpharmacological approaches. Antiemetic drugs available to treat or prevent PONV include phenothiazines, antihistamines, anticholinergics, benzamides, butyrophenones and 5-HT(3) antagonists. Since available drugs still present undesired adverse effects and are not completely able to control PONV, clinical investigations are ongoing for more effective and better tolerated agents; indeed, the ideal antiemetic drug might be cost-effective for routine use.

Pharmacotherapy of postoperative nausea and vomiting

Postoperative nausea and vomiting (PONV) are two of the most common and unpleasant side effects following anaesthesia and surgery. Despite the development of new anti-emetics and a vast amount of published research, PONV continues to be a problem, especially in high-risk patients. Recent interest has focused on the use of a combination of agents, acting on different receptors and the adoption of a multimodal approach to tackle this problem. The search for the most cost-effective strategy has also been a major goal. This article will discuss the risk factors and physiology of PONV, currently available therapies, the use of a multimodal approach and the cost-effectiveness of PONV management. Finally, recommendations for the prophylaxis and treatment of PONV will be discussed.

Combination therapy for postoperative nausea and vomiting - a more effective prophylaxis?

The problem of postoperative nausea and vomiting (PONV) remains far from being resolved. Despite the introduction of new classes of antiemetics and a vast amount of published research, there is a general impression that there has been little progress in this area. The multifactorial etiology of PONV might be better addressed using a combination of drugs acting at different receptor sites. This approach of balanced antiemesis may be the answer towards achieving a significant improvement in the management of PONV. This article will cover the different strategies used to prevent PONV with particular emphasis on combination antiemetics. A review of the currently available methods to manage PONV as well as the physiological and pharmacological basis of combination therapy is presented.

Myopexy (Faden) results in more postoperative vomiting after strabismus surgery in children

BACKGROUND

Strabismus correction in children is associated with a high incidence of postoperative nausea and vomiting. The purpose of this prospective, double-blind study was to examine the influence of the surgical method for correction of squint on the incidence of postoperative vomiting.

METHODS

One hundred and twenty consecutive children aged 2-12 years, scheduled for elective strabismus surgery, were enrolled in this prospective, double-blind study. A standardised total intravenous anaesthesia was given to all children. The development of perioperative oculocardiac reflex was noted and the number of episodes of vomiting during the first 48 h postoperatively was recorded. At the completion of the study, the children who were operated with myopexy according to Faden, were allocated to a Faden group, those without a myopexy to the non-Faden group. All the patients included in this study were operated on by the same surgeon with standardised techniques.

RESULTS

The Faden group was younger, lighter and the operation time was longer (P<0.05). The incidence of vomiting was greater in the Faden group; 53% versus 12% (P<0.05). The incidence of oculocardiac reflex was similar in both groups; 40% in the Faden versus 28% in the non-Faden group, respectively. The total dose of propofol and alfentanil was similar between the groups. Requirement of analgesics for postoperative pain was similar in both groups. The only independent risk factor for postoperative vomiting was the Faden operation.

CONCLUSION

The surgical method used for strabismus correction in children has a great influence on the incidence of postoperative vomiting. The Faden operation is associated with a very high incidence of postoperative vomiting; this particular group of patients has to be considered as a high risk group for postoperative vomiting and deserves an antiemetic prophylaxis.

Does midazolam alter the clinical effects of intravenous ketamine sedation in children? A double-blind, randomized, controlled, emergency department trial

STUDY OBJECTIVE

This study was conducted to investigate the frequency and severity of adverse effects, specifically emergence phenomena, experienced by patients receiving intravenous ketamine with or without midazolam for sedation in a pediatric emergency department.

METHODS

Patients aged 4.5 months to 16 years receiving ketamine sedation were prospectively enrolled in a double-blind, randomized, controlled study at a university-affiliated children's hospital-pediatric ED. All patients received ketamine (1 mg/kg) and glycopyrrolate (5 microgram/kg) intravenously. Patients were randomly assigned to receive midazolam (0.1 mg/kg) intravenously or no midazolam. Total time of sedation, sedation efficacy, and adverse effects were recorded. Adverse effects were compared between patients receiving ketamine versus those who received ketamine and midazolam. Additional comparisons were made based on age and number of ketamine doses administered.

RESULTS

Two hundred sixty-six patients were studied; 129 received ketamine and 137 patients received ketamine and midazolam. Time of sedation and efficacy of sedation were equivalent between groups. Overall, adverse effects with ketamine sedation included respiratory events (12 [4.5%]), vomiting (50 [18.7%]), emergence phenomena in the pediatric ED (71 [26.7%]), and emergence phenomena at home (60 [22.4%]). Significant emergence phenomena in the pediatric ED (ie, nightmares, hallucinations, and severe agitation) occurred in 7.1% of the ketamine group and in 6.2% of the ketamine-midazolam group, a rate difference of 0.8 (95% confidence interval [CI] -5.3 to 7.0). The addition of midazolam led to an increased incidence of oxygen desaturation events (ketamine 1.6% versus ketamine-midazolam 7.3%; rate difference -5.7, 95% CI -10.6 to -0.9) but a decreased incidence of vomiting (ketamine 19.4%, ketamine-midazolam 9.6%, rate difference 9.8, 95% CI 1.4 to 18.2). The incidence of emergence phenomena and significant emergence phenomena was not affected by the addition of midazolam. However, the addition of midazolam was associated with more agitation in the pediatric ED in children 10 years or older (ketamine 5.7% versus ketamine-midazolam 35.7%; rate difference -30.0, 95% CI -10.7 to -49.3). Age breakdown further showed 6.3% (95% CI 0.9 to 11.6) more episodes of oxygen desaturation in the ketamine-midazolam group in children younger than 10 years, and 12.1% (95% CI 1.5 to 22.6) more vomiting episodes in the ketamine group in children younger than 10 years.

CONCLUSION

Ketamine and combined ketamine and midazolam provided equally effective sedation. The addition of midazolam did not alter the incidence of emergence phenomena. Vomiting occurred more frequently in the ketamine only group, whereas oxygen desaturation occurred more frequently in the ketamine-midazolam group. These findings were more pronounced in patients younger than 10 years. Parental and physician satisfaction remained high for all patients receiving intravenous ketamine sedation.

Postoperative nausea and vomiting in children

The prevention and treatment of postoperative nausea and vomiting (PONV) in children remains an important challenge for the pediatric anesthesiologist. Despite a clearer understanding of the physiology of emesis and with the development of new anesthetic and antiemetic agents, PONVis still an important cause of morbidity. The approach to minimizing this complication is multifactorial and includes proper preoperative preparation, a rational approach to intraoperative antiemetic prophylaxis, choice of appropriate anesthetic agents and techniques, and a definitive plan for postoperative care. This review gives a brief account of the numerous classes of antiemetics available to treat this condition and the various strategies that can be used to reduce PONV.

Efficacy, dose-response, and adverse effects of droperidol for prevention of postoperative nausea and vomiting

PURPOSE

To estimate the efficacy and harm produced by droperidol in the prevention of postoperative nausea and vomiting (PONV).

METHODS

Systematic search (MEDLINE, EMBASE, Cochrane library, hand-searching, bibliographies, all languages, up to May 1999) for randomised comparisons of droperidol with placebo in surgical patients. Relevant end points were prevention of early PONV (up to six hours postoperatively), and late PONV (24 hr), and adverse effects. Combined data were analysed using relative risk and NNT.

RESULTS

In 76 trials, 5,351 patients received 24 different regimens of droperidol. The average incidence of early and late PONV in controls was 34% and 51%, respectively. Droperidol was more efficacious than placebo in preventing PONV. In adults, the anti-nausea effect was short-lived, and there was no dose-responsiveness; with 0.25 to 0.30 mg the number-needed-to-treat (NNT) to prevent early nausea was 5. For both early and late anti-vomiting efficacy there was dose-responsiveness; best efficacy was with 1.5 mg to 2.5 mg (NNT, 7). In children, there was dose-responsiveness; best efficacy was with 75 microg x kg(-1) (NNT to prevent early and late vomiting, 4). Two children had extrapyramidal symptoms with droperidol (NNT in children, 91; in any patient, 408). There was dose-responsiveness for sedation and drowsiness (with 2.5 mg the NNT was 7.8). Droperidol prevented postoperative headache (NNT, -25).

CONCLUSIONS

Droperidol is anti-emetic in the surgical setting. The effect on nausea is short-lived but more pronounced than the effect on vomiting. Sedation and drowsiness are dose-dependent, extrapyramidal symptoms are rare, and there is a protective effect against headache.

Prevention and treatment of postoperative nausea and vomiting

Pain, nausea and vomiting are frequently listed by patients as their most important perioperative concerns. With the change in emphasis from an inpatient to outpatient hospital and office-based medical/surgical environment, there has been increased interest in the 'big little problem' of postoperative nausea and vomiting (PONV). Currently, the overall incidence of PONV is estimated to be 25 to 30%, with severe, intractable PONV estimated to occur in approximately 0.18% of all patients undergoing surgery. PONV can lead to delayed postanaesthesia care unit (PACU) recovery room discharge and unanticipated hospital admission, thereby increasing medical costs. The aetiology and consequences of PONV are complex and multifactorial, with patient-, medical- and surgery-related factors. A thorough understanding of these factors, as well as the neuropharmacology of multiple emetic receptors [dopaminergic, muscarinic, cholinergic, opioid, histamine, serotonin (5-hydroxy-tryptamine; 5-HT)] and physiology [cranial nerves VIII (acoustic-vestibular), IX (glossopharyngeal) and X (vagus), gastrointestinal reflex] relating to PONV are necessary to most effectively manage PONV. Commonly used older, traditional antiemetics for PONV include the anticholinergics (scopolamine), phenothiazines (promethazine), antihistamines (diphenhydramine), butyrophenones (droperidol) and benzamides (metoclopramide). These antiemetics have adverse effects such as dry mouth, sedation, hypotension, extrapyramidal symptoms, dystonic effects and restlessness. The newest class of antiemetics used for the prevention and treatment of PONV are the serotonin receptor antagonists (ondansetron, granisetron, tropisetron, dolasetron). These antiemetics do not have the adverse effects of the older, traditional antiemetics. Headache and dizziness are the main adverse effects of the serotonin receptor antagonists in the dosages used for PONV. The serotonin receptor antagonists have improved antiemetic effectiveness but are not as completely efficacious for PONV as they are for chemotherapy-induced nausea and vomiting. Older, traditional antiemetics (such as droperidol) compare favourably with the serotonin receptor antagonists regarding efficacy for PONV prevention. Combination antiemetic therapy improves efficacy for PONV prevention and treatment. In the difficult-to-treat PONV patient (as in the chemotherapy patient), suppression of numerous emetogenic peripheral stimuli and central neuroemetic receptors may be necessary. This multimodal PONV management approach includes use of: (i) multiple different antiemetic medications (double or triple combination antiemetic therapy acting at different neuroreceptor sites); (ii) less emetogenic anaesthesia techniques; (iii) adequate intravenous hydration; and (iv) adequate pain control.

Perianesthesia care of adult and pediatric strabismus surgery patients

Strabismus procedures on children and adults are frequently performed in an outpatient setting. Perianesthesia care of patients having strabismus procedures may be optimized by recognizing the characteristics of strabismus patients, the frequently associated diagnoses that may affect perioperative care, and the specific surgical techniques used to treat strabismus. Complications including postoperative nausea, pain, prolonged PACU stay, and unplanned postoperative admissions can be minimized and treatment facilitated by preparing patients with preoperative instructions, careful choice of anesthetic agents and postoperative medications, and appropriate perioperative care. This report will provide a brief review of surgical strabismus, including current techniques, and present guidelines for perioperative care of pediatric and adult strabismus patients.

A comparison: the efficacy of sevoflurane-nitrous oxide or propofol-nitrous oxide for the induction and maintenance of general anesthesia

STUDY OBJECTIVE

To compare sevoflurane-nitrous oxide with propofol-nitrous oxide for the induction and maintenance of anesthesia, and to determine the rates of recovery following each anesthetic.

DESIGN

Randomized, controlled study.

SETTING

Teaching hospital.

PATIENTS

50 ASA physical status I and II patients, ranging in age from 18 to 70 years.

INTERVENTIONS

General anesthesia was induced with either sevoflurane or propofol and maintained with 60% to 70% nitrous oxide and either sevoflurane or a propofol infusion and supplemental fentanyl. At the conclusion of surgery, the oxygen flow was increased to 6 L/min and all anesthetics were discontinued simultaneously. Patients were monitored for the nature and speed of induction and emergency from anesthesia.

MEASUREMENTS AND MAIN RESULTS

Induction of anesthesia was significantly slower in the sevoflurane group than in the propofol group (2.0 +/- 1.1 vs. 0.8 +/- 0.5 min, respectively). The ease of induction and the time required for emergence from anesthesia were the same in both study groups (eye opening: 9.0 +/- 4.4 min vs. 8.0 +/- 5.0 min; following commands: 11.2 +/- 5.0 min vs. 9.8 +/- 6.9 min; extubation: 9.1 +/- 4.5 min vs. 8.6 vs. 5.1 min in the sevoflurane and propofol groups, respectively). Patients in the sevoflurane group experienced nausea and vomiting more frequently than patients in the propofol group (13 and 5 patients vs. 3 and 0 patients in the sevoflurane and propofol groups, respectively), which were not related to the administration of neostigmine or intraoperative opioids.

CONCLUSION

Sevoflurane allows for rapid inhalation induction of, and emergence from, general anesthesia.

Postoperative nausea and vomiting: the outpatient enigma

Postoperative nausea and vomiting is an all too common side effect of surgery and anesthesia. The usual occurrence of vomiting within the first 24 hours following surgery involves one quarter to one third of all patients. Although nausea and vomiting is typically self-limiting, lasting less than 24 hours, the consequences must be considered. Patient dissatisfaction, adverse physiological sequelae, delays in discharge from the ambulatory facility, unanticipated hospital admission, and added cost are problems associated with postoperative vomiting. This article will review the multiple factors contributing to postoperative nausea and vomiting and discuss contemporary strategies for the management of these factors.

Treatment of postoperative nausea and vomiting: comparison of propofol, droperidol and metoclopramide

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.

[Does oral ondansetron reduce the incidence of nausea and vomiting after surgery for strabismus in children?]

OBJECTIVE

To compare the efficacy of oral ondansetron with oral metoclopramide for the prevention of postoperative vomiting and nausea in children undergoing strabismus surgery.

STUDY DESIGN

Prospective, randomized, double-blind trial.

PATIENTS

Thirty children of physical class 1, age 9 +/- 4 years, scheduled for strabismus surgery, were randomized into two groups (ondansetron and metoclopramide).

METHODS

In the ondansetron group, the children received the first oral dose of ondansetron (4 mg) 1 hour before induction of anaesthesia and the other doses 8 and 16 hours later. In the metoclopramide group, children received metoclopramide (5 mg) in the same conditions. Anaesthesia was induced with thiopentone, vecuronium and fentanyl and maintained with halothane and N2O/O2. Patients were evaluated by an independent observer for nausea and emesis in recovery room (0-2 h) and on the ward. The adverse effects of oral ondansetron and metoclopramide were assessed.

RESULTS

There were non-significant differences between the two groups for incidence of nausea and vomiting (40% and 53% in ondansetron group versus 33 and 60% in metoclopramide group, respectively.

CONCLUSION

Unlike intravenous ondansetron, oral ondansetron is not superior to metoclopramide for the prevention of nausea and vomiting caused by strabismus surgery in children.

The effects of ketorolac and fentanyl on postoperative vomiting and analgesic requirements in children undergoing strabismus surgery

Fifty-four ASA I and II children 1 to 10 yr of age undergoing strabismus surgery were randomized to receive in a double-blind fashion intravenous ketorolac (0.9 mg/kg), fentanyl (1 microgram/kg), or saline placebo (2 mL) during a standardized general anesthetic. Patients received no analgesic or antiemetics intraoperatively except for the study drug. Patients receiving ketorolac or placebo compared to fentanyl had a significantly lower incidence of postoperative vomiting in the day surgery unit (DSU) (P = 0.03) and overall (DSU plus home) (P = 0.005). The severity (number of episodes) of post-operative vomiting was significantly lower in the DSU, at home (first 24 h after hospital discharge), and overall for patients receiving ketorolac or placebo compared to fentanyl (P < 0.01). Postoperative pain scores and frequency of acetaminophen administration did not differ among the study groups, suggesting that the intraoperative use of ketorolac or fentanyl during pediatric strabismus surgery is unnecessary. No patients required fentanyl postoperatively, indicating that rectal acetaminophen administered in the postanesthesia recovery room provides sufficient analgesia for pediatric strabismus surgery. In conclusion, neither ketorolac nor fentanyl was associated with less postoperative vomiting or analgesic requirements compared to saline placebo administered during pediatric strabismus surgery. Fentanyl should be avoided, as it was associated with a significantly greater incidence of postoperative vomiting compared to ketorolac or placebo.

Anesthesia for magnetic resonance imaging in children: a low incidence of protracted post-procedure vomiting

STUDY OBJECTIVE

To determine the incidence and severity of vomiting in pediatric patients who have had inhalation anesthesia for magnetic resonance imaging (MRI).

DESIGN

A retrospective study of consecutive pediatric patients who had anesthesia for MRI.

SETTING

A large university hospital with an integrated clinic facility.

PATIENTS

234 children who required an MRI under general anesthesia over a 30 month period (July 1989 to February 1992).

MEASUREMENTS AND MAIN RESULTS

The duration of inhalation anesthesia was 105 +/- 33 minutes. Following anesthesia, the time to oral intake was 92 +/- 69 minutes. Eighteen patients (9%) experienced one or more episodes or emesis. In 14 of the 18 patients, vomiting occurred once and did not delay the intake of oral fluids or the discharge time from clinic when compared with the rest of the patients. Only one patient had frequent vomiting (more than three episodes), and all vomiting resolved spontaneously without anti-emetic therapy in less than eight hours following anesthesia.

CONCLUSIONS

Protracted post-procedure vomiting is an infrequent complication of inhalation anesthesia for MRI. Inhalation anesthesia may be a less important cause of postoperative vomiting than factors such as the type of operative procedure, use of opioids, or presence of postoperative pain.

Midazolam reduces vomiting after tonsillectomy in children

The purpose of this study was to assess the effect of midazolam on vomiting after tonsillectomy in children. We compared 215 children aged 1.5-14 yr undergoing tonsillectomy or adenotonsillectomy under general anaesthesia with nitrous oxide and halothane. In a double-blind fashion the subjects were administered either placebo or midazolam 75 micrograms.kg-1 iv after induction of anaesthesia. After the operation, the number of emetic episodes and the length of stay in hospital were recorded. The groups were similar with respect to age, weight, sex, mode of induction, duration of anaesthesia, surgical procedure, opioid administration and length of stay in the PAR and the Day Care Surgical Unit. The 108 midazolam-treated children had a lower incidence (42% vs 57%) of vomiting than the placebo group, P < 0.02. The placebo group had a higher incidence (9% vs 2%) of unscheduled admissions to hospital due to nausea and vomiting, P < 0.05. It is concluded that midazolam administered intravenously to children intraoperatively reduces vomiting after tonsillectomy.

Prevention of emesis after strabismus repair in children: a prospective, double-blinded, randomized comparison of droperidol versus ondansetron

STUDY OBJECTIVE

To compare the effectiveness of ondansetron with droperidol in preventing postoperative emesis in children after strabismus repair.

DESIGN

Randomized, double-blind study.

PATIENTS AND SETTING

57 ASA physical status I and II children aged 3 to 14 years, undergoing outpatient strabismus repair in two separate study centers.

INTERVENTIONS

Patients were randomized to receive either 0.15 mg/kg intravenous (i.v.) ondansetron or 0.075 mg/kg i.v. droperidol shortly after induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Number of episodes of emesis and times to discharge from the recovery room and ambulatory center were assessed. Twenty-nine (94%) of 31 children who received ondansetron and 21 (81%) of 26 children who received droperidol were emesis-free (p = NS). There were no significant differences in the number of episodes of emesis on the day after surgery or times to discharge.

CONCLUSIONS

Ondansetron is at least as effective as droperidol in reducing the frequency of emesis in children after strabismus repair, and it did not shorten times to discharge home. The low number of patients in our study may have masked a difference in effect between the two groups. The clinician should decide whether the increased cost of ondansetron justifies its use over other antiemetics.