Efficacy of a restrictive anti-emetic strategy in patients with low risk of postoperative nausea and vomiting (PONV)- A randomised control trial

Nausea and vomiting are one of the most frequently encountered symptoms in patients who have undergone a surgery.They can be especially distressing to the patient and hamper a speedy recovery, more so in case of day care procedures.  Post operative Nausea and Vomiting or PONV as it is frequently referred to as, is a very important factor in the overall patient satisfaction in the hospital.The estimated incidence of PONV is around 30% in the overall surgical population and can be as high as 80% in high risk cohorts.The occurrence of PONV is also associated with increased length of PACU stay and increased health care costs.Hence, reducing the incidence of PONV should be a constant strife for the anaesthesiologist.

 The risk factors for an increased risk of PONV can be classified as patient factors like female sex, young age, non -smokers and a history of motion sickness/PONV and procedural factors like duration of anaesthesia, use of inhalational anaesthetics and nitrous oxide, General anaesthesia and use of post operative opioids.

 Apfel and colleagues devised a scoring system to risk stratify patients as high or low risk for PONV. The ‘Apfel Score’ includes female gender, non-smoker, history of PONV or motion sickness and post operative use of opioids, with a higher score meaning a higher chance of the patient experiencing PONV. Koivuranta score includes the risk factors of Apfel score along with duration of surgery > 60 minutes.

 The fourth consensus guidelines for the prevention and management of PONV was published in 2020 under the auspices of the American Society of Enhanced Recovery and Society for Ambulatory Anaesthesia. This is a comprehensive document for a clinician to practice in the perioperative arena. As per the consensus guidelines a multimodal therapy is advocated in patients to prevent PONV, with two different classes of anti-emetics in low risk and three or more different classes of anti-emetics in case of high risk patients.

 According to the fourth consensus guidelines for the management of PONV ‘there are very few studies directly comparing the efficacy of a risk-based “restrictive” antiemetic prophylaxis approach to a more liberal multimodal antiemetic prophylaxis approach’

They also state that direct comparisons of different combination therapies of anti-emetics is lacking and any evidence in that regard would prove invaluable.