evaluation of the effect of pre-operative over-fasting on post-operative vomiting in children undergoing bone marrow aspiration at a tertiary care setting in sri lanka: a prospective cohort study

Background and Aims: Non-adherence to standard fasting guidelines may result in perioperative complications. We aimed to determine the association between pre-operative over-fasting and post-operative vomiting amongst children undergoing bone marrow aspiration under general anaesthesia. Methods: A prospective cohort study was conducted from May 2015 to April 2016 in children undergoing bone marrow aspiration under general anaesthesia and their caregivers. Children fasted for ≥3 hours from last clear fluid intake constituted the exposed group (n = 202) while children fasting for <3 h constituted the non-exposed group (n = 202). The primary outcome was the development of post-operative vomiting during the 6 h following induction of anaesthesia. The awareness of the caregiver regarding the importance of keeping the child fasting before anaesthesia was evaluated. Results: The mean (standard deviation) duration time of fasting of the exposed and non-exposed groups were 7.2 (2.4) and 2.2 (0.3) h, respectively. Thirty-two (15.8%) children in the exposed group and 17 (8.4%) children in the non-exposed group developed post-operative vomiting. The relative risk of developing post-operative vomiting amongst over-fasting children was 1.9 (95% confidence interval [CI] = 1.1–3.3, P = 0.02), while adjusting to the age, it was 2.1 (95% CI = 1.1–4). Significantly more caregivers were clear about the fasting advice in the non-exposed group than in the exposed group (P < 0.001). Conclusion: Over-fasting is a significant risk factor to develop post-operative vomiting in paediatric anaesthetic practice.