UBC Theses and Dissertations

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UBC Theses and Dissertations

Feasibility of a pilot study to assess the safety and antipyretic efficacy of acetaminophen in critically ill patients. Bains, Vininder Kour


Preliminary, mostly small observational studies, suggest that febrile intensive care unit (ICU) patients may be at higher risk of acetaminophen-associated hypotension and that acetaminophen may be a less effective antipyretic in this population than previously thought. A pilot double-blinded, randomized controlled trial was conducted to examine four questions: (a) what is the feasibility of conducting this study, (b) is there a difference in incidence of clinically significant hypotensive events, and/or blood pressure in the four hours post intervention between febrile, non-brain injured patients who received either a single dose acetaminophen or a placebo, (c) is there a difference in fever burden between participants who received the treatment versus placebo, and (d) what are the relationships between heart rate, blood pressure, core temperature, and fever burden? Over nine months, 83% of the 950 admitted ICU patients were screened, 100 patients were eligible but due to logistical challenges, only 27 were invited to participate, of which 17 refused. Only six of the 10 participants completed the study, and of those five were randomized to the acetaminophen group. The eligibility rate increased from 10.0% to 16.3% (p = 0.016) after small changes to the inclusion criteria were made. The sample size was too small to draw conclusions regarding the utility of outcome measures, participant safety, or the hemodynamic or antipyretic effects of acetaminophen; however, no participant had a safety event. Participants had variable heart rate, blood pressure, and fever patterns. There was little or no discernable antipyretic effect of acetaminophen in the five participants who received the drug. Additionally, strong linear relationships were detected between mean pre-post intervention differences in fever burden and mean arterial pressure (MAP) as well as core temperature and heart rate (p = 0.003 for both). Mean difference in MAP increased by 2.20 mmHg for every 1 °C-hour increase in net change in fever burden (R² = 0.906; 95% C I [1.214, 3.186]). Mean difference in heart rate increased by 4.840 beats/minute for every 1 °C increase in mean difference in core temperature (R² = 0.905; 95% CI [2.665, 7.014]).

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