Preoxygenation in the Elderly: Comparison of 3-min and Four Deep Breath Techniques

Özet

Introduction: Preoxygenation with 100% O2 before anesthesia induction is a standard procedure in anesthesia practice. With preoxygenation, alveolar washout of air mixture in functional residual volume provides higher alveolar oxygen concentration up to 100% which leads to increased alveolar oxygen reserve, so during apnea, time to desaturation levels is delayed. We studied two different preoxgenation methods in elderly patients and compared four deep breath and 3-min techniques to decide which one is more efficient in this patient group. Methods: A total of 30 patients over 60 years were included in the study. Electrocardiography, systolic artery pressure (SAP), heart rate (HR), and SpO2 were monitored. Data were recorded before preoxygenation, after anesthesia induction, after intubation, and when SpO2 reached to 93%. Blood gas analysis was also performed at the same time points. Time to reach to SpO2 levels of 97%, 95%, and 93% was also recorded. Group I (n=15) patients were asked to breath normally for 3 min after the mask was tightly applied to the patients’ face. In Group II (n=15), the patients were asked to take four deep breaths when ordered by the anesthetist and then breath normally. Anesthesia induction was performed after the completion of preoxygenation. Following the induction of anesthesia and complete muscular paralysis, entubation of the trachea was performed. The distal end of the tube was left open, the patients were not ventilated until SpO2 levels reached to 93%, and, then they were ventilated with 100% oxygen and the study ended. Data were recorded before preoxygenation, after anesthesia induction, after intubation, and when SpO2 reached to 93%. Blood gas analysis was also performed at the same time points. Time to reach to SpO2 levels of 97%, 95%, and 93% were also recorded. Results: The study was completed with 29 patients. There were no difference in demographic variables, Hg levels and time to apnea (p>0.05). Median age of the patients was 65, 8 years (61–76) in Group I and 65. 2 years (60–74) in Group II. The HR were different in two groups at the time points of SpO2 97%, 95%, and 93%, and time to reach these desaturation points was significantly different in four deep breath group of patients (p<0.001, p<0.01, and p<0.05). Discussion and Conclusion: The physiological changes affect lung capacities and reserves in elderly patients. We conclude that, as the effectiveness of vital capacity breaths was decreased in these patients, 3 min of tidal breaths should be the method of choice for preoxygenation in this patient group.