Preinduction incentive spirometry versus deep breathing to improve apnea tolerance during induction of anesthesia in patients of abdominal sepsis

BACKGROUND: Abdominal sepsis is associated with varied degree of hypoxemia and atelactasis in the lung and can enhance the onset of desaturation of arterial blood during apnea. AIMS: This study looked at methods to improve safety margin of apnea during induction of anesthesia in these high-risk patients. SETTINGS AND DESIGN: It was a randomized, single blind study on adult patients presenting for emergency laparotomy due to peritonitis in a university teaching hospital setting. MATERIALS AND METHODS: In group 1 (IS) (n = 32), three sessions of incentive spirometry (IS) were performed within one hour before induction of anesthesia. In group 2 (DB) (n = 34), patients were subjected to deep breathing sessions in a similar manner. All patients received preoxygenation (100%) by mask for 3 min, followed by rapid-sequence induction of anesthesia using fentanyl, thiopental, and suxamethonium and endotracheal intubation. Patients were subjected to a period of apnea by keeping the end of the endotracheal tube open to air till they developed 95% hemoglobin saturation (SpO 2) by pulse oxymetry. Positive pressure ventilation was resumed at the end. We observed for hemodynamic changes, apnea time, and SpO 2 (100%) recovery time on resuming ventilation. Arterial blood gas samples were taken before intervention, after IS or DB, after preoxygenation, and at the end of apnea. STATISTICAL ANALYSIS USED: One-way analysis of variance (ANOVA), X 2 test, Kaplan-Meier graph, and log-rank tests were applied to compare the two study groups. RESULTS: Oxygenation level in group 1 (265 ± 76.7 mmHg) patients was significantly (P < 0.001) higher than in group 2 (221 ± 61.8 mmHg)at the end of preoxygenation. The apnea time (median: lower bound - upper bound Confidence Interval apnea time) (272:240-279 s) in group 1 (IS) patients was significantly higher P < 0.05) than in group 2 (180:163-209 s) patients. Saturation recovery time (35:34-46 s) in group 1 (IS) patients was also quicker than in group 2 patients (48:44-58 s). CONCLUSIONS: IS in the preoperative period is superior to deep breathing sessions for improving apnea tolerance during induction of anesthesia in abdominal sepsis patients.