Méta-analyse : ondansétron en prophylaxie des nausées et vomissements postopératoires chez l’adulte et l’enfant après craniotomie

New insights into the pathophysiology and risk factors for PONV

Postoperative nausea and vomiting (PONV) affects patient outcomes and satisfaction. New research has centered on evaluation of post-discharge and opioid-related nausea and vomiting. Mechanical and drug effects stimulate the release of central nervous system neurotransmitters acting at receptors in the vomiting center, area postrema, and nucleus of the solitary tract. Brain surgery has allowed insight into specific central emetogenic areas. Stimuli from peripheral organs act through afferent vagus neurons and a parasympathetic response causing nausea and vomiting. Opioids stimulate mu receptors in the chemoreceptor trigger zone and cholinergic receptors in the vestibular system. Opioids also affect gastrointestinal (GI) tract mechanics by decreasing gastric emptying, intestinal motility, GI peristalsis, and secretions. Regional blocks and non-opioid multimodal analgesia help to decrease nausea and vomiting. Patient, surgery, and anesthesia factors contribute to risk and degree of PONV experienced. Pharmacogenetics plays a role in gene typing as antiemetic medication metabolism results in varying drug effectiveness. Risk scoring systems are available. Individualized multimodal plans can be designed as part of an enhanced recovery after surgery protocol.

Comparison of the antiemetic effect of ramosetron with ondansetron in patients undergoing microvascular decompression with retromastoid craniotomy: a preliminary report

BACKGROUND

Microvascular decompression with retromastoid craniotomy carries an especially high risk of postoperative nausea and vomiting. In this study, we compare the antiemetic efficacy of ramosetron and ondansetron in patients undergoing microvascular decompression with retromastoid craniotomy.

METHODS

Using balanced anesthesia with sevoflurane and remifentanil infusion, ondansetron 8 mg (group O, n = 31) or ramosetron 0.3 mg (group R, n = 31) was administered at the dural closure. The incidence and severity of postoperative nausea and vomiting, required rescue medications and the incidence of side effects were measured at post-anesthetic care unit, 6, 24 and 48 hours postoperatively. Independent t-tests and the chi-square test or Fisher's exact test were used for statistical analyses.

RESULTS

There were no differences in the demographic data between groups, except for a slightly longer anesthetic duration of group R (P = 0.01). The overall postoperative 48 hour incidences of nausea and vomiting were 93.6 and 61.3% (group O), and 87.1 and 51.6% (group R), respectively. Patients in group R showed a less severe degree of nausea (P = 0.02) and a lower incidence of dizziness (P = 0.04) between 6 and 24 hours.

CONCLUSIONS

The preventive efficacy of ramosetron when used for postoperative nausea and vomiting was similar to that of ondansetron up to 48 hours after surgery in patients undergoing microvascular decompression with retromastoid craniotomy. A larger randomized controlled trial is needed to confirm our findings.

Different treatment benefits were estimated by clinical trials performed in adults compared with those performed in children

OBJECTIVE

Our main objective was to see whether the therapeutic benefit observed in placebo controlled randomized controlled trials (RCTs) is different between adults and children.

STUDY DESIGN AND SETTING

We searched three electronic databases for meta-analyses that included double-blind, placebo-controlled RCTs with separate results for adults and children. The selected reviews were classified according to disease and drug used. The heterogeneity of treatment response between adults and children was measured using ratio of odds ratios (RORs).

RESULTS

We selected 89 meta-analyses and calculated RORs for 124 drugs. Heterogeneity in the direction of the treatment effect was observed in one drug and heterogeneity in the quantity of the treatment effect for 13 drugs, indicating significantly different treatment effect in adults when compared with children. RORs were not significantly different from 1 for 110 drugs. For 36 of these drugs, the treatment effect was confirmed in both populations.

CONCLUSION

We found different treatment benefits estimated by clinical trials performed in adults compared with those performed in children for 14 of 124 drugs. Data on dose adjustment and child age groups from RCTs were not adequately reported to investigate their influence on the treatment benefit dissimilarities.

A randomized clinical trial comparing the efficacy and safety of ramosetron versus ondansetron in patients undergoing abdominal surgery under general anesthesia

BACKGROUND

Post-operative nausea and vomiting is one of the most common and distressing complications after anesthesia and surgery. It may lead to serious post-operative complications. Ramosetron is a newer 5-HT3 receptor antagonist and has more potent and longer duration of antiemetic effects compared to first generation 5HT3 receptor antagonists. The purpose of this study was to compare the efficacy of Ramosetron for the prevention of post-operative nausea and vomiting with that of Ondansetron in patients undergoing abdominal surgeries under general anesthesia.

METHODS

In this randomized, double-blind study, 60 patients, 18-60 years of both genders falling under ASA I-II category scheduled for abdominal surgery were included. Group I received I.V ramosetron 0.3 mg while group II received I.V Ondansetron 4 mg at the time of extubation. The standard general anesthetic technique was used throughout. Postoperatively the incidences of nausea, vomiting, and safety assessments were performed at 1, 2, 6, and 24 h during the first 24 h after surgery.

RESULTS

There were no differences between groups with respect to patient demographics. The percentage of patients who had complete response (no PONV, and no need for another rescue antiemetic) from 0 to 24 h after anesthesia was 56% with ramosetron and 33% with ondansetron. The corresponding rates at 1, 2, 6, and 24 h after anesthesia were 76% and 63%, 76% and 50%, 100 and 83%, 100 and 93%, respectively. Safety profiles of the two drugs were comparable, as no clinically serious adverse effects caused by study drugs were observed in either of the groups.

CONCLUSION

Our study concludes that prophylactic therapy with ramosetron is highly efficacious than ondansetron in preventing PONV in patients undergoing abdominal surgery under general anesthesia.