Comparison of post-operative shivering, nausea and vomiting between pre-intubation and pre-extubation intravenous paracetamol in percutaneous nephrolithotripsy under general anaesthesia

Background: Post-operative shivering, nausea and vomiting is frequently observed in patients undergoing percutaneous nephrolithotripsy [PCNL] under general anaesthesia. It is not only distressing to patients but can also be detrimental because of the increased oxygen consumption, coagulopathies, delayed recovery and increased blood pressure. Prophylactic paracetamol administration has shown to be effective in reducing post-operative shivering by decreasing the hypothalamic temperature set point. When paracetamol is administered prior to extubation, it can reduce nausea and vomiting by reducing the post-operative pain. We aimed to compare the effects of prophylactic pre-induction and pre-extubation intravenous paracetamol on post-operative shivering, nausea and vomiting. Correlation of severe post-operative shivering with patient’s age, BMI, and amount o f irrigation fluid used were also evaluated. Methods: This prospective observational study was carried out on 72 patients undergoing PCNL under GA. Patients receiving intravenous 1gm paracetamol 20 minutes prior to intubation were grouped as PI-PCM while those receiving it 20 minutes prior to extubation over 20 minutes were grouped as PE-PCM. We recorded age, BMI, core body temperature (Pre-induction, before giving muscle relaxant and then 30 minutes thereafter, after extubation and just before shifting to the post-operative recovery), duration of PCNL, amount of irrigation fluid, post-operative shivering using Crossley & Mahajan score and PONV using the Afpel score every 10 minutes for 2 hours. Results: Demographic data such were comparable between the PI-PCM and PE-PCM groups. The occurrence of severe post-operative shivering (Crossley-Mahajan grade >II) was significantly higher (p 0.033) in the PE-PCM group as compared to the PI-PCM group. Post-operative shivering had statistically highly significant negative correlation with BMI and positive correlation with the amount of irrigation volume used. Incidence of PONV was statistically higher (p0.023) in the PI-PCM group as compared to the PE-PCM group. Conclusion: Prophylactic intravenous parcetamol administration can significantly reduce post-operative shivering in PCNL patients under GA. Similarly, it’s administration prior to extubating can significantly decrease the post-operative nausea and vomiting.