PONV: a problem of inhalational anaesthesia?

Area of Science:

• Anesthesiology
• Pharmacology

Background:

• Postoperative nausea and vomiting (PONV) remains a common complication following general anesthesia, affecting a significant patient population.
• Volatile anesthetics are recognized as emetogenic, but their contribution to PONV is less significant than other factors like perioperative opioids and patient-specific risks.

Purpose of the Study:

• To quantify the impact of various factors, including volatile anesthetics and perioperative opioids, on the incidence of PONV.
• To evaluate the effectiveness of anti-emetic prophylaxis strategies in relation to patient risk and anesthetic agents.

Main Methods:

• Analysis of a large multicenter factorial design trial (IMPACT) evaluating anti-emetic strategies.
• Inclusion of patient-specific risk factors in simplified risk score calculations for PONV prediction.
• Comparison of PONV incidence across different anesthetic techniques, including volatile anesthetics, propofol-based total intravenous anesthesia, and regional anesthesia.

Main Results:

• Volatile anesthetics are emetogenic, but their role in PONV is less critical than often assumed.
• Patient-specific risk factors are the primary predictors of PONV and influence the efficacy of anti-emetic prophylaxis.
• Various anti-emetic strategies (dexamethasone, droperidol, ondansetron) offer a consistent relative risk reduction of 25-30% and act independently.

Conclusions:

• While volatile anesthetics contribute to PONV, perioperative opioids and patient-specific factors are more significant causes.
• Anti-emetic prophylaxis is most effective in high-risk patients, with efficacy independent of the specific anti-emetic used or the presence of volatile anesthetics.
• Strategies like total intravenous anesthesia or opioid-free regional anesthesia may be considered for PONV prevention in high-risk individuals.