Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist and nabilone, a synthetic cannabinoid.     

Physiology and pharmacology of nausea and vomiting

The physiology of nausea and vomiting is poorly understood. The initiation of vomiting varies and may be due to motion, pregnancy, chemotherapy, gastric irritation or postoperative causes. Once initiated, vomiting occurs in two stages, retching and expulsion. The muscles responsible for this sequence of events are controlled by either a vomiting centre or a central pattern generator, probably in the area postrema and the nearby nucleus tractus solitarius. Drugs which induce vomiting include ipecacuanha, a gastric irritant, and apomorphine, a dopamine-receptor agonist. Opioid drugs also induce vomiting, but opioid antagonists are not useful to treat nausea and vomiting. Anti-emetic drugs consist of a variety of neurotransmitter antagonists and may act in the periphery, the central nervous system or both sites. The most important drugs are antagonists at muscarinic, dopamine D₂, 5-HT₃, histamine H₁ and neurokinin NK₁ receptors. These drugs are discussed with particular attention to post-operative nausea and vomiting (PONV).     

Physiology and pharmacology of nausea and vomiting

The physiology of nausea and vomiting is poorly understood. The initiation of vomiting varies and may be due to motion, pregnancy, chemotherapy, gastric irritation or post-operative causes. Once initiated, vomiting occurs in two stages, retching and expulsion. The muscles responsible for this sequence of events are controlled by either a vomiting centre or a central pattern generator, probably in the area postrema and the nearby nucleus tractus solitarius. Drugs which induce vomiting include ipecacuanha, a gastric irritant, and apomorphine, a dopamine-receptor agonist. Opioid drugs also induce vomiting, but opioid antagonists are not useful to treat nausea and vomiting. Anti-emetic drugs consist of a variety of neurotransmitter antagonists and may act in the periphery, the CNS or both sites. The most important drugs are antagonists at muscarinic, dopamine D₂, 5-HT₃, histamine H₁ and neurokinin NK₁ receptors. These drugs are discussed with particular attention to post-operative nausea and vomiting (PONV).     

Betamethasone does not prevent nausea and vomiting induced by ipecacuanha

BACKGROUND: Corticosteroids reduce the incidence of PONV but the mode of action is not known. The purpose of this study was to evaluate if betamethasone has serotonin (5-HT) antagonistic effects. Ipecacuanha is known to release serotonin and therefore it was used to induce nausea and vomiting. The 5-HT3 antagonist ondansetron was used as a control substance. METHODS: In a randomized, double-blind, cross-over, placebo-controlled study 10 healthy male and female volunteers (6 M/4F), mean age 19.5 (18-23) years, mean weight 69.7 (53-84) kg, were studied on three occasions separated by at least 1 week. They were randomly allocated to receive pretreatment with betamethasone 8 mg, ondansetron 8 mg, or normal saline 2 ml as placebo on each occasion, 15 min before oral ingestion of 30 ml of Ipecacuanha syrup. After ingestion of ipecacuanha, vomitings were recorded and the intensity of nausea was estimated with a visual analog scale during 2 h. RESULTS: During the first 2 h after ingestion of ipecacuanha nine of the 10 volunteers vomited both after betamethasone and placebo. No volunteer vomited after ondansetron (P < 0.01 vs. betamethasone and placebo). The max VAS for nausea was significantly higher after betamethasone and placebo compared to ondansetron (P < 0.01). There were no statistically significant differences of the max VAS for nausea between betamethasone and placebo. CONCLUSION: This study in volunteers has shown that betamethasone does not prevent nausea and vomiting induced by oral intake of ipecacuanha syrup. As ipecacuanha releases 5-hydroxytryptamin, it can be concluded that betamethasone does not have 5-HT3 antagonistic effects.     

Drugs for preventing postoperative nausea and vomiting in adults after general anaesthesia: an abridged Cochrane network meta-analysis

Postoperative nausea and vomiting is a common adverse effect of anaesthesia. Although dozens of different anti-emetics are available for clinical practice, there is currently no comparative ranking of efficacy and safety of these drugs to inform clinical practice. We performed a systematic review with network meta-analyses to compare, and rank in terms of efficacy and safety, single anti-emetic drugs and their combinations, including 5-hydroxytryptamine₃, dopamine-2 and neurokinin-1 receptor antagonists; corticosteroids; antihistamines; and anticholinergics used to prevent postoperative nausea and vomiting in adults after general anaesthesia. We systematically searched for placebo-controlled and head-to-head randomised controlled trials up to November 2017 (updated in April 2020). We assessed how trustworthy the evidence was using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) and Confidence In Network Meta-Analysis (CINeMA) approaches for vomiting within 24 h postoperatively, serious adverse events, any adverse event and drug class-specific side-effects. We included 585 trials (97,516 participants, 83% women) testing 44 single drugs and 51 drug combinations. The studies' overall risk of bias was assessed as low in only 27% of the studies. In 282 trials, 29 out of 36 drug combinations and 10 out of 28 single drugs lowered the risk of vomiting at least 20% compared with placebo. In the ranking of treatments, combinations of drugs were generally more effective than single drugs. Single neurokinin-1 receptor antagonists were as effective as other drug combinations. Out of the 10 effective single drugs, certainty of evidence was high for aprepitant, with risk ratio (95%CI) 0.26 (0.18–0.38); ramosetron, 0.44 (0.32–0.59); granisetron, 0.45 (0.38–0.54); dexamethasone, 0.51 (0.44–0.57); and ondansetron, 0.55 (0.51–0.60). It was moderate for fosaprepitant, 0.06 (0.02–0.21) and droperidol, 0.61 (0.54–0.69). Granisetron and amisulpride are likely to have little or no increase in any adverse event compared with placebo, while dimenhydrinate and scopolamine may increase the number of patients with any adverse event compared with placebo. So far, there is no convincing evidence that other single drugs effect the incidence of serious, or any, adverse events when compared with placebo. Among drug class specific side-effects, evidence for single drugs is mostly not convincing. There is convincing evidence regarding the prophylactic effect of at least seven single drugs for postoperative vomiting such that future studies investigating these drugs will probably not change the estimated beneficial effect. However, there is still considerable lack of evidence regarding safety aspects that does warrant investigation.     

Current therapy for management of postoperative nausea and vomiting: the 5-HT3 receptor antagonists

The control of postoperative nausea and vomiting (PONV) remains a problem in spite of the improvements achieved with newer anesthetic agents, such as propofol, and newer antiemetics. Management of PONV is difficult, this is most likely due to the multiple receptors and neurotransmitters in the central nervous system that mediate the emetic response, and to the multifactorial etiology of PONV. Studies of the four major 5-hydroxytryptamine (serotonin) subtype-3 (5-HT₃) receptor antagonists suggest that they have similar safety and efficacy for prevention and treatment of PONV. These drugs lack the significant side effects observed with traditional antiemetics. Combination regimens of 5-HT₃ receptor antagonists and traditional antiemetics can improve antiemetic efficacy. Areas of future study include comparing the cost effectiveness of these agents and determining optimal combinations of antiemetics to further reduce the incidence of PONV.     

Granisetron prevents nausea and vomiting during spinal anaesthesia for caesarean section

Background: Nausea and vomiting during spinal anaesthesia for caesarean section are common and unpleasant complications. This study was undertaken to evaluate the efficacy of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for prophylactic treatment of nausea and vomiting in parturients undergoing nonemergent caesarean section under spinal anaesthesia.
Methods: In a randomized, double-blind, placebo-controlled trial, 100 patients, 21–38 years, received either placebo (saline) or granisetron at 3 different doses (20 μg · kg^-1, 40 μg · kg^-1 or 80 μg · kg^-1) (n=25 for each) intravenously immediately after clamping of the foetal umbilical cord. Nausea, vomiting and safety assessments were performed during spinal anaesthesia for caesarean section.
Results: The treatment groups were similar with regard to maternal characteristics and operative management. The incidence of nausea and vomiting was 64%, 52%, 14% and 12% after administration of placebo and granisetron in a dose of 20 μg · kg^-1, 40 μg · kg^-1 and 80 μg · kg^-1, respectively ( P <0.05; overall Fisher's exact probability test). No clinically important adverse effects were observed in any group.
Conclusions: Prophylactic use of granisetron in a minimum dose of 40 μg · kg^-1 is effective for preventing nausea and vomiting during spinal anaesthesia for caesarean section.
© Acta Anaesthesiologiat Scandinavica 42 (1998)     

Dexamethasone versus ondansetron in combination with dexamethasone for the prophylaxis of postoperative vomiting in pediatric outpatients: a double‐blind,randomized, placebo‐controlled clinical trial

Objectives: To determine the frequency of postoperative vomiting (POV) in children submitted to outpatient surgery and to compare the efficacy of antiemetic drugs in preventing this complication. Background: Nausea and vomiting are common in the immediate postoperative period following anesthetic and surgical procedures. Compared to adults, pediatric patients are more likely to develop postoperative nausea and vomiting, the incidence of which ranges from 8.9% to 42%. Methods: This double‐blind, randomized, placebo‐controlled clinical trial included 129 children. The participants were randomized into three prophylactic treatment groups: dexamethasone (n = 43), ondansetron in combination with dexamethasone (n = 44), and placebo (n = 42). The variables studied were the frequency of POV and the incidence of vomiting after the patient had been discharged from hospital, the need for antiemetic rescue therapy in the postanesthesia care unit (PACU), need for hospitalization, and the time the patient remained in the PACU. A significance level of 5% was adopted. Results: Postoperative vomiting occurred in 12.4% of the children, with no statistically significant difference between the groups: 6.8% in the group receiving ondansetron combined with dexamethasone, 14.3% in the placebo group, and 14% in the group that received dexamethasone alone (P = 0.47). Furthermore, no significant difference was found between the groups with respect to the time the children remained in the PACU, and only five patients reported having vomited following discharge from hospital. Conclusions: The prophylactic use of antiemetic drugs failed to reduce the incidence of POV in pediatric outpatient surgery with a low emetic potential; therefore, routine prophylaxis may be unnecessary.     

Prophylaxis of postoperative nausea and vomiting: controversies in the use of serotonin 5-hydroxytryptamine subtype 3 receptor antagonists

Postoperative nausea and vomiting (PONV) continues to be a "big little problem" despite recent advances in anesthesia. Because of an increased interest in, and the abundant publications on this topic, guidelines for the management of PONV were published in 2003. Several key but controversial issues regarding PONV prophylaxis were left unaddressed, however. These included whether clinical differences exist between the 5-hydroxytryptamine subtype 3 (5-HT3) receptor antagonists, concern over optimal dosage and timing of administration, optimal 5-HT3 receptor antagonist combination therapy, and whether rescue therapy is effective after prior administration of the same or a different 5-HT3 receptor antagonist. The application of these antiemetics in clinical practice has raised questions regarding the role of the 5-HT3 receptor antagonists in the treatment of postdischarge nausea and vomiting and opioid-induced nausea and vomiting. A brief overview of the incidence, risk factors and current management recommendations for PONV and current controversies with special emphasis on the 5-HT3 receptor antagonists, is discussed.     

The incidence of postoperative nausea and vomiting after caesarean section in patients with hyperemesis gravidarum: a retrospective cohort study

BackgroundPostoperative nausea and vomiting is one of the most common anaesthetic complications of caesarean section. This study examined the association between hyperemesis gravidarum during pregnancy and nausea and vomiting after caesarean section.MethodsA single-centre, retrospective cohort study, using electronic databases of patients with and without hyperemesis gravidarum, undergoing caesarean section from 2015 to 2019. The incidence and severity of postoperative nausea and vomiting were established by a review of the documentation of administration of postoperative anti-emetics within the 24-h period after surgery, and examined using univariable, multivariable binary and ordered logistic regression models.ResultsData were compared for 76 patients with hyperemesis gravidarum and 315 patients without the condition. The incidence of postoperative nausea and vomiting in the hyperemesis group versus the non-hyperemesis group was 43.4% vs 29.6%, respectively. The odds of experiencing postoperative nausea and vomiting was 1.95 times higher in women with hyperemesis gravidarum than in those without (aOR 1.95, 95% CI 1.13 to 3.36, P=0.016). The odds of having more severe postoperative nausea and vomiting were greater in the hyperemesis gravidarum group (aOR 1.91, 95% CI 1.14 to 3.20, P=0.014).ConclusionPatients with hyperemesis gravidarum are more likely to develop nausea and vomiting after caesarean section, and this is likely to be of greater severity than in those without the condition. This finding should assist the effective provision of intra-operative and postoperative anti-emetics for patients with hyperemesis gravidarum undergoing caesarean section.     

Postdischarge nausea and vomiting: A review of current literature

Postoperative nausea and vomiting continues to occur in approximately one-third of patients who have surgery despite newer medications and emerging guidelines for care. There is a paucity of literature that relates to patients who experience postdischarge nausea and vomiting after outpatient surgery. The purpose of this article is to review the current knowledge in the area of postdischarge nausea and vomiting. The findings were that the problems with postdischarge nausea and vomiting (PDNV) have not been as thoroughly assessed and evaluated as nausea and vomiting immediately postsurgery. More research needs to be conducted in this population, as the rate of surgeries performed in this setting will only increase.     

Effect of intraoperative intravenous crystalloid infusion on postoperative nausea and vomiting after gynaecological laparoscopy: comparison of 30 and 10 ml kg(-1)

Background. I.V. fluid administration has been shown to reducepostoperative nausea and vomiting (PONV). The optimum dose isunknown. We tested the hypothesis that administration of i.v.crystalloid of 30 ml kg^–1 would reduce the incidence ofPONV compared with 10 ml kg^–1 of the same fluid. Methods. A total of 141 ASA I female patients undergoing electivegynaecological laparoscopy were randomized, in double-blindfashion, to receive either 10 ml kg^–1 (n=71; CSL-10 group)or 30 ml kg^–1 (n=70; CSL-30 group) of i.v. compound sodiumlactate (CSL). Results. In the first 48 h after anaesthesia, the incidenceof vomiting was lower in the CSL-30 group than in the CSL-10group (8.6% vs 25.7%, P=0.01). Anti-emetic use was less in theCSL-30 group at 0.5 h (2.9% vs 14.3%, P=0.04). The incidenceof severe nausea was significantly reduced in the treatmentgroup at awakening (2.9% vs 15.7%, P=0.02), 2 h (0.0% vs 8.6%,P=0.04) and cumulatively (5.7% vs 27.1%, P=0.001). The numbersneeded to treat to prevent vomiting, severe nausea and antiemeticuse in the first 48 h were 6, 5 and 6, respectively. Conclusion. I.V. administration of CSL 30 ml kg^–1 to healthywomen undergoing day-case gynaecological laparoscopy reducedthe incidence of vomiting, nausea and anti-emetic use when comparedwith CSL 10 ml kg^–1.     

Effects of propofol on ipecacuanha-induced nausea and vomiting

Background : The purpose of this study was to evaluate if propofol has 5-HT₃ antagonistic effects. Ipecacuanha is known to release serotonin (5-HT) in the gastrointestinal tract and therefore ipecacuanha syrup was used to induce nausea and vomiting. The 5-HT₃ antagonist ondansetron was used as a control substance.
Results : During the first 150 min after ingestion of ipecacuanha there were no retchings during the ondansetron infusion ( P = 0.01 vs placebo, P =0.02 vs propofol) and significantly fewer retchings during propofol infusion compared to placebo ( P <0.02). There was no nausea during the ondansetron infusion ( P <0.01 vs placebo and propofol) but the volunteers experienced nausea both during the placebo and propofol infusion (NS).
Conclusion : This study in volunteers has shown that propofol reduces the intensity of retching after oral intake of ipecacuanha syrup. As ipecacuanha releases 5-hydroxytryptamine, it can be concluded that propofol may have a weak 5-HT₃ antagonistic effect.
Method : Ten healthy male volunteers (20–37 years) were studied on three occasions and were randomly allocated to receive a concomitant infusion of propofol (initial bolus 0.1 mg kg^-1 then 1 mg kg^-1h^-1), ondansetron (initial bolus 0.11 mg kg^-1 then 14 μg kg^-1 h^-1) and placebo on either occasion. The infusions started 30 min before oral ingestion of 30 ml of ipecacuanha and continued until 150 min after the intake. The number of retchings was recorded and the intensity of nausea was estimated by the subjects on a visual analog scale.     

Studies in postoperative sequelae. Nausea and vomiting—still a problem

We collected data on postoperative nausea and vomiting from 3850 patients aged 11–91 years. Thirty-seven percent of the 3244 patients who received a general anaesthetic reported nausea and 23.2% vomited. Twenty percent of the 606 patients who received a local anaesthetic reported nausea and 11.4% vomited. Of the general anaesthetic patients reporting nausea, 72.2% were women, and the mean age was lower than for those who did not (p < 0.001). Similarly for vomiting, 74.0% were women and again the mean age was lower (p < 0.001). Of the local anaesthetic patients reporting nausea, 62.0% were women and the mean age was lower than for those who did not (p < 0.001). Similarly for vomiting, 68.1% were women and again the mean age was lower (p < 0.001). Anxiety before general, but not local, anaesthesia was associated with postoperative nausea (p < 0.001) but not vomiting. Patients from the gynaecological, orthopaedic, ENT and general surgical wards had higher incidences of postoperative nausea and vomiting. Linear visual analogue pain scores were higher in patients with postoperative nausea and vomiting in both general and local anaesthesia groups (p < 0.001).     

Comparison of surgical site and patient's history with a simplified risk score for the prediction of postoperative nausea and vomiting

Although site of surgery and previous occurrence of postoperative nausea and vomiting are often used to decide whether prophylactic anti-emetic drugs are indicated, the value of these predictors is unclear. We compared these two risk factors against a simplified four-factor risk score. We analysed data from 1566 adult inpatients who received balanced anaesthesia without prophylactic anti-emetics. Sensitivity, specificity, predictive value and area under the receiver operating characteristic curve were used to quantify predictive properties. Nausea and vomiting occurred in 600 (38.3%) patients within 24 h. Sensitivity and specificity were, respectively, 47% and 59% for surgical site; 47% and 70% for history of postoperative nausea and vomiting; and 58% and 70% for risk score with three or more factors. The area under the curve for surgical site was 0.53 (95% CI 0.50-0.56); that for patient's history was 0.58 (95% CI 0.56-0.61) while for risk score it was 0.68 (95% CI 0.66-0.71; P < 0.001). Prediction using surgical site or patient's history alone was poor while the simplified risk score provided clinically useful sensitivity and specificity.     

Granisetron reduces incidence of nausea and vomiting after breast surgery

Background: Postoperative nausea and vomiting (PONV) remains a troublesome problem. This study was performed to evaluate the antiemetic efficacy of prophylactic granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, on the incidence of PONV in patients undergoing general anaesthesia for breast surgery.
Methods: In a randomized, placebo-controlled, double-blind study, 50 female patients, 45–68 years, were given a single dose of either placebo (saline, n=25) or granisetron (40 ug kg^-1, n= 25) intravenously over 2–5 min immediately before the induction of anaesthesia. Postoperatively, during the first 24 hours after anaesthesia, the incidence of PONV and adverse events was recorded.
Results: The treatment groups were similar for patient demographics, types of surgery, anaesthetic and postoperative management. Postoperatively, the incidence of PONV was 48% and 16% after administration of placebo and granisetron, respectively ( P < 0.05). No differences in the incidence of other adverse events were observed between the two groups.
Conclusion: Granisetron is an effective antiemetic for preventing PONV in patients undergoing general anaesthesia for breast surgery.     

The use of droperidol decreases postoperative nausea and vomiting after gynecological laparoscopy

We evaluated whether or not routine prophylaxis with 2.5 mg of droperidol would efficiently prevent postoperative nausea and vomiting (PONV). Fifty-two patients scheduled for elective gynecological laparoscopic surgery were eligible for this study. Anesthesia was induced using propofol, fentanyl, and vecuronium, and maintained with sevoflurane in nitrous oxide, fentanyl, and vecuronium. Patients were randomized to one of two groups: group 1 patients (n = 23) received 2.5 mg droperidol intravenously when the surgery was started, while group 2 patients (n = 29) did not receive any droperidol. At the conclusion of the surgery, the patient was extubated on satisfactory emergence from general anesthesia. Any episodes of nausea and vomiting, rescue medications, and adverse effects were recorded until the next morning after the surgery. There were no differences in the duration of anesthesia on surgery between the groups, but the total fentanyl dose in group 1 was higher than that in group 2. Episodes of nausea and vomiting and the need for metoclopramide in group 1 were lower than in group 2, though the total fentanyl dose in group 1 was higher than in group 2. There were no differences in the need for analgesics between the groups. The use of 2.5 mg droperidol safely decreased PONV after gynecological laparoscopy.     

盐酸帕洛诺司琼预防上腹部手术后硬膜外吗啡镇痛所致的恶心呕吐

目的 观察和评价帕洛诺司琼对上腹部手术后硬膜外吗啡镇痛引起的恶心呕吐的预防效果和安全性.方法 择期行上腹部手术并术后接受硬膜外吗啡镇痛患者60例,随机分为帕洛诺司琼组（P组）和托烷司琼组（T组）.手术结束前30 min,P组患者缓慢静注帕洛诺司琼0.25 mg,T组患者缓慢静注托烷司琼6 mg.观察记录两组患者术后24 h、48 h VAS及Ramsay评分、恶心呕吐的程度,计算恶心呕吐有效控制率.同时记录患者腹胀、头痛、椎体外系症状等不良反应.结果 两组患者术后24 h及48 h的VAS及Ramsay评分差异无统计学意义.P组患者术后24 h的恶心及呕吐有效控制率分别为80.0%和73.3%,T组分别为63.3%和60.0%;P组患者术后48 h的恶心及呕吐有效控制率分别为90.0%和93.3%,T组分别为66.6%和63.3%.两组患者术后24 h恶心、呕吐有效控制率差异无统计学意义.P组患者术后48 h恶心、呕吐有效控制率明显优于T组患者（P 〈 0.05）.帕洛诺司琼的不良反应主要为头痛.结论 腹部手术后24 h内,帕洛诺司琼预防吗啡硬膜外镇痛所致的恶心呕吐的效果与托烷司琼相当,但术后48 h预防恶心呕吐的效果优于托烷司琼,且不良反应发生率低,程度较轻,安全性好.     

A risk score for postoperative nausea and/or vomiting in women undergoing cesarean delivery with intrathecal morphine

BackgroundPostoperative nausea and/or vomiting affects up to 80% of parturients undergoing cesarean delivery, but there is a lack of obstetric-specific risk-prediction models. We performed this study to identify postoperative nausea/vomiting risk factors in parturients undergoing cesarean delivery, formulate an obstetric-specific prediction model (Duke score), and compare its performance against the Apfel score.MethodsA post-hoc analysis of data from two randomized controlled trials studying nausea/vomiting in women undergoing cesarean delivery with intrathecal morphine. Potential risk factors for postoperative nausea/vomiting within 24 h of surgery with univariate associations with P ≤0.20 were considered for inclusion in the multivariable analysis. After identifying the final multivariable model, we derived our Duke score by assigning points to the selected factors. We then tested the association of the Duke and Apfel scores with postoperative nausea and vomiting, and compared the area-under-the-receiver operating characteristic curve.ResultsAnalysis included 260 parturients, of whom 146 (56.2%) experienced postoperative nausea/vomiting. Non-smoking during pregnancy (OR 2.29 [95% CI 1.12 to 4.67], P=0.023), and history of postoperative nausea/vomiting after cesarean delivery and/or morning sickness (2.09 [1.12 to 3.91], P=0.021) were independent predictors of postoperative nausea/vomiting and included in the Duke score. Both Duke and Apfel scores trended linearly with postoperative nausea/vomiting risk (Duke P=0.001; Apfel P=0.049) and had comparable areas-under-the-receiver operating characteristic curve (Duke 0.63 [0.57 to 0.70]; Apfel 0.59 [0.52 to 0.65], P=0.155).ConclusionsBoth Duke and Apfel scores exhibited similar but poor predictive performance. Until better tools are developed, routine prophylactic anti-emetics appears to be a reasonable approach in this patient population.     

Dolasetron decreases postoperative nausea and vomiting after breast surgery

In a randomized, placebo-controlled, double-blind trial, we compared the efficacy of dolasetron, dexamethasone, and metoclopramide in a preventing postoperative nausea and vomiting in women undergoing breast surgery. Patients were allocated randomly to one of four groups (20 patients each): group A received 12.5 mg dolasetron, group B received 8 mg dexamethasone, group C received 20 mg metoclopramide, and group D received placebo intravenously. If patients complained of retching or vomiting or if patients demanded an antiemetic, 1.25 mg droperidol was administered intravenously. To quantify postoperative nausea and vomiting, the following score was used: 0 = no nausea, 1 = nausea, 2 = retching, 3 = single vomiting, 4 = multiple vomiting. Dolasetron and dexamethasone reduced the postoperative nausea and vomiting score significantly (p < 0.02 versus metoclopramide; p < 0.0001 versus placebo). Metoclopramide also reduced the postoperative nausea and vomiting score (p < 0.02 versus placebo). Fisher's exact test showed a significant reduction of vomiting in the dolasetron and dexamethasone groups compared with metoclopramide-treated patients (p < 0.007) and placebo-treated patients (p < 0.000006) and a significantly lower rate of nausea in comparison to the placebo group (p < 0.009). There were no significant differences between the metoclopramide and the placebo groups (using Fisher's exact test). The use of postoperative droperidol was significantly lower in both the dolasetron group (p < 0.04 versus metoclopramide; p < 0.0001 versus placebo) and dexamethasone group (p < 0.04 versus metoclopramide; p < 0.0001 versus placebo), as well as in the metoclopramide group (p < 0.02 versus placebo). Intravenous dolasetron and dexamethasone were equally effective and both are more effective than metoclopramide for preventing vomiting after breast surgery. Also both were significantly superior to either metoclopramide or placebo for postoperative nausea and vomiting and the need for droperidol rescue.