ObjectiveTo investigate the pulmonary function after positive end-expiratory pressure(PEEP)in patients treated with ureterolithotomy through retroperitoneal laparoscopic ureterolithotomy under protective ventilation.

MethodsSeventy patients treated with laparoscopic ureterolithotomy under protective ventilation were divided into the control group and observation group(35 cases in each group).All patients were treated with intermittent positive pressure ventilation from anesthesia-induced intubation to pneumoperitoneum, the tidal volume for 10 mL/kg, ventilation frequency for 15 times/min, respiratory ratio for 1:2 and oxygen concentration for 60% in observation group were implemented, and the tidal volume for 7 mL/kg, ventilation frequency for 25 times/min, respiratory ratio for 1:1.5 and P_ETCO₂ for 35-45 mmHg in control group were implemented.The PEEP was additionally set in observation group on the basis of the control group, and the parameter was 5 cmH₂O.The blood gas analysis of arterial blood sample was performed.Before 10 min of pneumoperitoneum, after 10, 30 and 60 min of pneumoperitoneum, at the end of pneumoperitoneum and before 10 min of extubation, the peak pressure(Ppeak) and mean airway pressure(Pmean) were observed, the intraoperative and postoperative dynamic lung compliance(Cdyn), oxygenation index(PaO₂/FiO₂), dead space rate(VO/VT) and alveolar-arterial oxygen partial pressure difference(A-aDO₂) were analyzed.

ResultsCompared with the control group, the Pmean from 10 to 60 min of pneumoperitoneum increased, and the differences of the Ppeak and Cdyn at each time-point were not significant in observation group.Compared with before 10 min of pneumoperitoneum, the Pmean increased after 10 to 60 min and at the end of pneumoperitoneum, and the Ppeak increased, and the Cdyn decreased in observation group after 10 to 60 min of pneumoperitoneum(P < 0.01).Compared with the control group, the PaO₂/FiO₂ increased, the A-aDO₂ and RI decreased(P < 0.05 to P < 0.01), and the difference of the VD/VT was not statistically significant in observation group after 30 min of pneumoperitoneum and before 10 min of extubation(P>0.05).Compared with before 10 min of pneumoperitoneum, the PaO₂/FiO₂ decreased, and the A-aDO₂ and RI increased in control group before 10 min of extubation and in observation group after 30 min of pneumoperitoneum(P < 0.05 to P < 0.01).

ConclusionsThe application of PEEP in patients treated with laparoscopic ureterolithotomy under protective ventilation is beneficial to the improvement of pulmonary function.