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Abstract

Introduction: Geriatric patients account for more than half of intensive care unit (ICU) admissions. Propofol is commonly utilized in this patient population for sedation during mechanical ventilation in the ICU. Decreased propofol dosing requirements for procedural sedation in geriatric patients compared to non-geriatric adults have been demonstrated; however, propofol dosage differences have not been compared between these patient groups in the ICU setting. The purpose of this study is to determine if propofol dosing requirements differ between geriatric and non-geriatric adult patients during sedation for mechanical ventilation in the ICU. Methods: This was an IRB-approved, retrospective study that enrolled adult patients in the medical ICU who received propofol for mechanical ventilation between September 1, 2012 and July 15, 2013. Patients who underwent therapeutic hypothermia, received concomitant continuous infusion of benzodiazepines, or received propofol only for procedural sedation were excluded. Propofol doses were titrated according to Richmond Agitation Sedation Scale (RASS) scores per an ICU, nurse-driven protocol. Data were collected for up to 14 days of propofol therapy. Patients were stratified as geriatric (age >/=65 years) or non-geriatric (age 19 – 64 years). The primary outcome was propofol dosing requirement. The secondary outcomes were the distribution of RASS scores between patient groups, length of stay, duration of mechanical ventilation, and mortality. Continuous data were analyzed with a Student's t-test or Mann-Whitney rank sum test. A Chi-square analysis was used for nominal data. Results: One hundred twenty-one patients (46 geriatric, 75 non-geriatric) were enrolled. Older patients weighed significantly less than younger patients at baseline (mean +/- SD = 77.4 +/- 20.7 vs. 93.3 +/- 33.6 kg; p=0.01); however, all other demographics were similar. Propofol dosage was no different between geriatric and non-geriatric patients (median [IQR] = 27.2 [21.5, 33] vs. 28.2 [21.6, 37.9] mcg/kg/min, respectively; p=0.33). There was no difference in the percentage of geriatric vs. non-geriatric patients with RASS scores of -5 to -3, -2 to 0, and >0 at any time (54 vs. 55%; p=0.88, 89 vs. 95%; p=0.44, and 30 vs. 39%;p=0.47, respectively). Geriatric and non-geriatric patients also had similar lengths of stay (15 [6.8, 18.3] vs. 13 [7, 18] days; p=0.42), duration of mechanical ventilation (2.5 [0.9, 7.3] vs. 3.1 [1.5, 6.9] days; p=0.71), and incidence of mortality (30 vs. 27%; p=0.81). Conclusions: Propofol dosing requirements and related clinical outcomes did not differ between geriatric and non-geriatric ICU patients. These results should be validated in a larger study.