Pulmonary Functional Changes In Ghanaian Patients Undergoing Spinal Anaesthesia

STRUCTURED ABSTRACT BACKGROUND: Although spinal Anaesthesia remains the anaesthetic technique of choice for many surgeries below the umbilicus, it may be associated with increased risk of cardiopulmonary complications such as hypotension, bradycardia and intraoperative cardiopulmonary arrest. Spinal Anaesthesia blocks autonomic, motor and sensory nerves which may affect pulmonary function. In the general population, reduction in the forced expiratory volume in one second (FEV1) is a robust predictor of sudden cardiac death in patients without primary heart or lung disease. It remains unclear how spinal Anaesthesia affects the pulmonary function of healthy individuals and how these changes impact on the incidence and/or severity of spinal Anaesthesia related intraoperative and postoperative complications. GENERAL AIM: To determine pulmonary functional changes and its association with perioperative cardiopulmonary complications in patients undergoing spinal Anaesthesia for elective surgery MATERIALS AND METHODS: An analytical cross-sectional study of 50 patients that meet the American Society of Anesthesiologist physical status class I or II with no history of primary heart or lung disease scheduled for elective surgery under spinal Anaesthesia were recruited for the study. Pulmonary function test (assessed by peripheral capillary oxygen saturation, spirometry and arterial blood gas) was done prior to induction of spinal Anaesthesia, 30min after induction of spinal Anaesthesia and at full recovery from spinal Anaesthesia. The changes in pulmonary function and how they predict the risk of adverse complications (hypotension, bradycardia, dysrhythmia, dyspnoea, nausea and vomiting) in the intraoperative and postoperative period were recorded. Repeated Measures ANOVA was used to determine pulmonary functional changes during spinal Anaesthesia and Logistic regression analysis was used to study the association between baseline pulmonary function and intraoperative and postoperative complication, with adjustments for potential covariates. RESULTS: Spinal Anaesthesia was associated with pulmonary functional changes. There was a significant reduction in FEV1 (best and predicted) and PEFR (best and predicted) during and post recovery from spinal Anaesthesia. There was a significant reduction in PH during Anaesthesia as compared to preoperative (baseline) and post recovery. This was observed with increase in PaCO2 and PaO2 though Arterial blood gas values were within normal physiological limit. There was no significant association between pulmonary function indices (FEV1predicted and PEFR predicted) and spinal Anaesthesia related complications. However, their ODDS ratio determined (preoperative, intraoperative and postoperative) indicated that spinal Anaesthesia related complications were more likely to occur for a unit change in the pulmonary function. CONCLUSION: Spinal Anaesthesia affects pulmonary function. This causes reduction in FEV1 intraoperatively and post operatively. Reduction in FEV1 may be a contributing factor to other mechanisms that result in spinal Anaesthesia related complication. Reduction in FEV1 may be more likely to predict the risk of development of spinal Anaesthesia related complication. RECOMMENDATION: Improved monitoring should be a mandatory safety requirement for all patients as changes in physiological parameters occur during and after spinal Anaesthesia. It is pertinent that all patients be monitored well into the postoperative phase of recovery.