PONV, beyond “Apfel” score

Sir, Avinash and Krishna are congratulated for their randomized controlled trial (RCT) on the impact of "Apfel" scoring system on postoperative nausea and vomiting (PONV).[1] Meanwhile, the authors account for the nature and duration of surgery (alongside the "Apfel" score); there are other potential factors to discuss in the matter. To begin with, adequate hydration with intravenous fluids has been proposed to favorably modulate the "baseline" PONV risk in the existing consensus guidelines.[2] Furthermore, a systematic review and meta-analysis (SRMA) by Kim et al. delineate a preventive effect of colloids on PONV following surgeries lasting >3 h (RR: 0.69; 95% CI: 0.53–0.89).[3] Withstanding, an outline of the fluid therapy in the RCT by Avinash and Krishna would have enhanced the contextual lucidity.[1] The importance of an anesthetic regime can simultaneously not be undermined with PONV being an outcome of interest.[3,4] Apfel et al.[4] included 2364 patients from 30 studies in their SRMA to suggest that acetaminophen reduces PONV when given "prophylactically" and, not when administered after the onset of pain. Interestingly, the metaregression results hinted at the corresponding benefit to be linked to the direct mechanisms or superior analgesia rather than the postoperative opioid reduction.[4] Thus, the "timing" of paracetamol administration also ought to be carefully presented in studies like the one by Avinash and Krishna focusing on PONV.[1,4] Finally, the "apparently" contradictory facts in the materials and the discussion sections regarding the use of nitrous oxide for anesthetic maintenance (without elucidating the fractional inspired oxygen concentrations employed) are equally difficult to overlook.[1] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.