Effects Of Varied Mechanical Ventilations On Postoperative Pulmonary Function In Aged Patients Undergoing Laparoscopy

Objective To investigate the effects of three patterns of mechanical ventilation on the recovery of postoperative pulmonary function and pulmonary complications( PPCs) in aged patients undergoing laparoscopy.Methods 104 patients, from 65 to 80 years old, undergone electived laparoscopic operation of upperabdominal region. According to the way of mechanical ventilation and with or without pulmonary disease, 66 patients without pulmonary disease were randomly divied into three groups , A, B, and C( n: A=20, B=20 and C=26); 38 patients with pulmonary disease were randomly divied into three groups, D, E and F( n: D=10, E=13 and F=15). group A and group D accepted IPPV intraoperative and SIMV postoprative, group B and group E accepted PEEP intraoperative and SIMV postoprative, group C and group F accepted IPPV intraoperative and SIMV , then CPAP postoprative. Variables related to arterial blood gas exchange, PETCO2 and hemodynamics were monitored before anesthesia, at 3h, 4h into pneumoperitoneum, at 45min after tracheal extubation, on postoperative days 1, 2, and 3. Pulmonary complications were noted on the 7thd.Results PaO2, PaO2/FiO2 and alveolar-arterial oxygen difference(A-aDO2) increased significantly(P<0.05 or P<0.01)at 3h,4h after inflation compared with preanesthesia in six groups.Then PaO2 and PaO2/FiO2 decreased after tracheal extubation while A-aDO2 increased .But these changes were not significant while comparing with each other. Oxygenation recovered completely in group C on first day postoperative, PaO2 and PaO2/FiO2 were higher than those in group A, and A-aDO2 was lower(P<0.01). Variables related to Oxygenation recovered to the basic levels on 2d in both group A and group B, but those in group D, E and F were different from those in group A(P<0.01). PaO2 , PaO2/FiO2 and A-aDO2 had not recovered to normal on 3d in group D and group E while those recovered completely in group F. The incidence of PPCs were not different among group A, B, D and E, but the incidence in group C was lower than that in group A, and group F was lower than group D(P<0.05).Conclusion CPAP postoperative ventilation early improved and accelerated the recovery of pulmonary oxygenation and reduced the incidence of PPCs, especially for aged patients with pulmonary disease.