Reduction in FEV following spinal anesthesia is associated with intraoperative complications: A prospective study.

Background And Aims: Although Spinal Anesthesia (SA) remains the technique of choice for many surgeries below the umbilicus, it is associated with multiple intraoperative complications. Sympathetic blockade and Bezold-Jarisch reflex do not fully explain SA-related cardiopulmonary complications. Reduction in FEV has been reported as a predictor of sudden cardiac death. This study aimed to determine the association between reduction in FEV following SA and adverse intraoperative cardiopulmonary complications.

Materials And Methods: A prospective study of 48 patients of ASA status I and II with no history of primary cardiopulmonary disease scheduled for elective surgery under SA. Spirometry was performed based on ATS/ERS guidelines before induction and 30 min after induction of SA. FEV% predicted was determined using GLI 2012 equations. Participants were grouped into two (∆FEV% < 10% and ∆FEV% ≥ 10%) based on reductions (∆) in FEV% predicted following SA. Logistic regression analyses were used to examine associations between ∆FEV% and intraoperative hypoxia, hypotension, bradycardia, and nausea/vomiting, with adjustments for age, gender, and BMI.

Results: The mean FEV% predicted following SA was lower than the mean FEV% predicted before SA (83.42 vs. 95.31,  = 0.001). In a fully adjusted model, ∆FEV% ≥ 10% was associated with an increased risk of hypoxia [AOR 13.55; 95% CI, 1.07-171.24,  = 0.044]. The positive associations between ∆FEV% ≥ 10% and hypotension [2.02 (0.33-12.46), 0.449], bradycardia [1.10 (0.28-4.25), 0.895] and nausea/vomiting [9.74 (0.52-183.94), 0.129] were not statistically significant.

Conclusion: Reduction in FEV% predicted following SA was associated with adverse intraoperative outcomes. FEV may play an important role in the association between SA and cardiopulmonary complications.