Predictors of hemodynamic compromise with propofol during defibrillator implantation: a single center experience.

BACKGROUND: Intra-operative hypotension has been reported in cardiac resynchronization therapy defibrillator (CRT-D) clinical trials but this phenomenon is not well characterized. The purpose of this study was to understand the frequency and determinants of intra-operative hypotension in patients undergoing defibrillator implantations.
METHODS: We retrospectively reviewed clinical data of all CRT-D implantations over a 21-month period. We compared a randomly selected contemporaneous group undergoing implantable cardiac defibrillator (ICD) implantations as a reference group. Procedure protocol involved intra-arterial blood pressure monitoring throughout the case. Lidocaine (1%) was routinely used along with propofol for sedation in all patients. Procedure time was defined as the time from initial administration of lidocaine for arterial line access, to completion of defibrillator pocket closure. Cumulative dose of propofol was calculated in each patient. Hypotension was defined as a fall in the systolic blood pressure of >or=30% from baseline or a systolic blood pressure of <or=80 mm Hg for >3 min. CRT-D and ICD patients were divided into hypotensive and non-hypotensive subsets.
RESULTS: The incidence of hypotension in the CRT-D group (N = 100) was 56%, as compared to 40% in the ICD group (N = 97). The mean duration of procedure in the CRT-D group was 114 +/- 95 min in the hypotensive subset versus 69 +/- 31.9 min in the non-hypotensive subset (p = 0.0015). The mean NYHA class in the hypotensive subset of the CRT-D group was 2.85 +/- 1.2 vs 2.2 +/- 1.5 in the non-hypotensive subset (p = 0.0179). Cumulative dose of propofol in the hypotensive subset of the CRT-D group was 386 +/- 22 mg, while that in the non hypotensive subset was 238.3 +/- 17 mg (p < 0.0001). Creatinine clearance in the hypotensive subset of the CRT-D group was 63.8 +/- 12.8 ml/min, while that in the non-hypotensive subset was 78.7 +/- 23.5 ml/min (p = 0.003). Patients in the CRT-D group who developed hypotension had a lower left ventricular ejection fraction of 21.1 +/- 10.2% versus 29 +/- 14.8% in the non-hypotensive subset (p = 0.0035).
CONCLUSIONS: Hypotension is a common occurrence during defibrillator implantation under conscious sedation. Risk factors for significant hypotension include: higher NYHA class, lower left ventricular ejection fraction, lower creatinine clearance, higher doses of propofol and longer procedure times.