A Retrospective Review of High Spinal Anesthesia for Aortic Valve Replacement in Patients with Aortic Stenosis
Monty Singh
University of Manitoba - Max Rady College of Medicine
Introduction: High spinal anesthesia (HSA) with local anesthetics, as a supplement to general anesthesia, for cardiac surgery has been used in Winnipeg for over 15 years. It decreases the stress and inflammatory response associated with cardiac surgery. The goal of this review was to document the use of HSA in addition to general anesthesia in patients with aortic stenosis (AS) undergoing aortic valve replacements. Methods: A retrospective case-control series documenting the clinical experience with HSA in patients with AS undergoing aortic valve replacements from 2000-2015 was conducted. The spinal patients were matched with controls based on age, sex, procedure, date, surgeon, facility, and ejection faction. The primary outcome measure was time to extubation, either in the operating room or in the intensive care unit. Secondary outcomes included: intraoperative glucose levels and insulin use (surrogate of the stress response), vasopressor and inotropic agent use, total analgesia consumption in the first 24 hours, re-intubation rate, hospital length of stay, and mortality rate. Comparisons were analyzed using student’s t test for continuous and chi-square for non-continuous variables. Results: Data was obtained for 98 patients who received HSA plus general anesthesia and for 87 control patients receiving general anesthesia only. Both groups were well matched in terms of demographics and medical co-morbidities. All patients had severe AS with no difference in aortic valve area or peak and mean pressure gradients. More HSA patients were extubated in the operative room [57.1% vs 31.0%, OR = 2.96, 95% CI = 1.62-5.43] and had a shorter duration of postoperative ventilation [13.3 +/- 16.6 vs 25.7 +/- 68.1 hours, P = 0.38]. HSA patients had lower peak glucose levels intraoperatively [9.2 +/- 2.1 vs 10.3 +/- 2.2 mmol/L, P = 0.002] and fewer patients required insulin [31.6% vs 47.1%, OR = 0.52, 95% CI = 0.29-0.94]. The total 24-hour analgesia use (morphine equivalents) was lower in the HSA group [18.3 +/- 12.0 vs 37.9 +/- 33.0 mg, p < 0.001]. There was no difference in re-intubation rate, mortality, ICU or hospital length of stay, or major medical complications amongst groups. Conclusion: HSA for aortic valve replacement in patients with severe AS was associated with an improved postoperative recovery profile as apparent by earlier extubation, shorter ventilation durations, lower inotrope/vasopressor use >24 hours, and less analgesia consumption within 24-hours