Hemodynamic Influences of Angiotensin-Converting Enzyme Inhibitors on Patients Undergoing Total Knee Arthroplasty With Spinal Anesthesia

Purpose: To determine if patients on angiotensin-converting enzyme inhibitors (ACEIs) had more severe hypotension or required higher doses of vasopressors compared to those who were not on ACEIs under spinal anesthesia for total knee arthroplasty (TKA). Methods: A retrospective chart review of 169 patients who underwent TKA with spinal anesthesia between August 2012 and December 2014 was performed. The patients were divided into two groups, i.e. patients on ACEIs (ACEIs group) and patients not on ACEIs (non-ACEIs group), for comparison. The preoperative characteristics, anesthesia records, and postoperative outcomes were reviewed. Results: The patients in the ACEIs group were more likely to have coexisting hypertension, diabetes mellitus, hyperlipidemia, and be on a beta blocker compared to patients in the non-ACEIs group. All of the patients showed decreased blood pressure immediately post spinal injection. Patients in the ACEIs group had lower systolic blood pressure (SBP) and diastolic blood pressure (DBP) compared to the non-ACEIs group at 10 minutes post spinal placement (p=0.01 for SBP and p= 0.005 for DBP). When comparing the two groups there was not a significant difference in severe hypotension or vasopressor requirements. However, the initial dose of propofol infusion for sedation was significantly lower in the ACEIs group (p=0.04). Conclusion: Patients on ACEIs showed lower blood pressure shortly after spinal injection compared to patients not on ACEIs. However, the difference was small and transient. The requirements of vasopressors were not significantly higher in patients on ACEIs undergoing spinal anesthesia for TKA.