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Acetaminophen-Induced Changes in Systemic Blood Pressure in Critically Ill Patients: Results of a Multicenter Cohort Study
Cantais A, Schnell D, Vincent F, et al. Crit Care Med. 2016; 44: 2192-2198.
Study Question: What is the incidence of hypotension associated with IV acetaminophen infusions administered to critically ill patients?
Study Description: This prospective, observational trial included patients from 3 intensive care units (ICU) that required IV acetaminophen per clinician discretion and had an arterial line for continuous monitoring. Acetaminophen was given as a 1 gram infusion over 30 minutes. Hypotension was defined as a decrease in mean arterial pressure (MAP) of greater than or equal to 15% from baseline. Blood pressure was recorded from the end of the infusion and for 3 hours thereafter. Diuretic and fluid bolus use within the previous 6 and 3 hours before acetaminophen infusion, respectively, were recorded, as were prior vasopressors and antihypertensive agents on the day of infusion. Lastly, fluid boluses and vasopressor use in response to acetaminophen-induced hypotension was documented.
Results: A total of 160 patients were included in the study. The median (interquartile range) baseline Logistic Organ Dysfunction score at the time of acetaminophen infusion was 7 (3-10), 132 (82.5%) required mechanical ventilation, and 60 (37.5%) were receiving vasopressors. Eighty-three (52%) patients developed hypotension during the 3-hour post-infusion monitoring period. Of these, 29 (34.9%) required intervention: 16 received crystalloids, 12 required increased vasopressor dose, and 1 received new vasopressor administration. Only two factors were independently associated with development of hypotension: diastolic pressure at 30 minutes (OR, 1.06 per 1% change; 95% CI, 1.03-1.11) and heart rate decrease more than 10% (OR, 2.73; 95% CI, 1.26-5.91). No baseline patient characteristics were associated with the development of hypotension.
Conclusion: In this critically ill population, IV acetaminophen-induced hypotension occurred in approximately 50% of patients, of which one-third required intervention to mitigate.
Perspective: Rates of hypotension in this study were similar to previous similar studies. However, the wide range of hypotension (13-59%) reported in previous literature is likely due to differences in patient populations and definitions of hypotension. The authors discuss a few possible mechanisms for acetaminophen-induced hypotension, but a clear cause remains elusive. Identifying patients at higher risk of this adverse effect would be beneficial as multi-modal analgesia becomes increasingly popular in critically ill patients.