Haemodynamic effects of intravenous acetaminophen in critically ill paediatric patients: a retrospective chart review

Objectives Haemodynamic changes following intravenous acetaminophen are well studied in adults. Limited data are published in critically ill paediatric patients, especially from the Middle East. We aim to investigate haemodynamic effects and incidence of hypotension with intravenous acetaminophen in critically ill children, with a focus on understanding factors influencing these effects. Methods We retrospectively reviewed patients who received intravenous acetaminophen between July and December 2022. A haemodynamic event was defined as drop of >15% in systolic blood pressure (SBP) or mean arterial blood pressure (MAP) within 120 min after drug administration. Hypotension was defined as either drop in SBP below the 5th percentile for age, or a haemodynamic event associated with tachycardia, increased lactate or treatment with fluid/vasopressors. Logistic regression was performed to quantify relationships between patients' characteristics and the occurrence of haemodynamic event and hypotension. Results A haemodynamic event was observed in 50/156 patients (32%) post-acetaminophen. Mean MAP (SD) before and after acetaminophen was 69.6 mm Hg (14.8) and 67.4 mm Hg (13.9), respectively (p=0.001). Mean SBP (SD) before and after acetaminophen was 95.4 mm Hg (18.2) and 92.8 mm Hg (19.2), respectively (p=0.006). Baseline MAP, median (interquartile range (IQR)) was 76.0 (64.0-85.3) and 66.0 (57.0-74.5) in patients with and without haemodynamic events, respectively (p=0.004). Only 38/156 patients (24%) met the definition for hypotension. Baseline MAP, median (IQR) was 62.0 (51.8-79.0) in patients with, and 68.5 (62.0, 79.3) in patients without hypotension (p=0.036). Baseline shock, vasoactives, mechanical ventilation and paediatric sequential organ failure assessment were not significantly associated with hypotension. Only MAP was found to be associated with both haemodynamic event (adjusted odds ratio (AOR) 1.05, 95% CI 1.02-1.10) and hypotension (AOR 1.06, 95% CI 1.02-1.10) even after controlling for other confounders. Conclusions Administration of intravenous acetaminophen in critically ill children can lead to haemodynamic changes, including clinically significant hypotensive events.