The Application Of Positive End-expiratory Pressure Ventilation In Laparoscopic Rectal Cancer Surgery

Objective: To observe the influence of PEEP on hemodynamics andrespiratory mechanics in laparoscopic rectal cancer surgery.Method: This study included30patients, who were undergoinglaparoscopic rectal cancer surgery in Bethune First Hospital of Jilin Universityfrom June2013to March2014. Patients were randomized to the VCV group (n=15) or PEEP group (n=15) according to a table of random numbers. In theoperating room, standard monitoring was established. A radial artery catheterwas inserted before induction of anesthesia. After anesthesia was induced,endotracheal intubation was completed (male ID=7.5mm; female ID=7.0mm)and the patient’s lungs were ventilated by a Ventilator. In the VCV group, theVentilator settings were tidal volume (Vt)8mL/kg, RR was adjusted tomaintain PETCO235-45mmHg. In the PEEP group, Vt was set at8mL/kg, PEEPat10cmH2O with RR was adjusted to maintain PETCO235-45mmHg. Inspiredoxygen concentration, I/E ratio, and Vt were held constant throughout the studyin both groups. The induced of anesthesia was taken supine position. CO2pneumoperitoneum was established when patient was stable and the IAP wasmaintained at14mmHg, and then30°Trendelenburg position was established.The patient was return to the supine position after pneumoperitoneum. Thesystolic pressure (SBP), diastolic pressure(DBP), mean artery pressure (MAP),heart rate (HR)， plateau pressure（Pplat）， peak airway pressure（Ppeak），respiratory rate（RR），oxygenation index (OI) and dynamic lung compliance(Cdyn) were recorded at the time before pneumoperitoneum（T1），5min afterTrendelenburg position（T2）,30min after Trendelenburg position（T3） and5min after pneumoperitoneum（T4）. Arterial blood samples were analyzed with an automated blood gas analyzer at each point.Result:1, There were no differences between the groups in patientcharacteristics and operative data.2, SBP, DBP and MAP increased at T2andT3without intergroup differences. HR was not significantly different at anytime.3, Pplat、 Ppeak increased at T2and T3and RR increased at T2,T3andT4in both groups compared with T1, without significant differences in Pplat、Ppeak and RR between the two groups.4, Patients in the PEEP group had asignificantly higher intraoperative OI than those in the VCV group at the fourpoints; patients in the PEEP group had a significantly increased Cdyn than thatof VCV group from T2to T4.Conclusion: In laparoscopic rectal cancer surgery，there was no differencein hemodynamics. Compared with mere VCV, PEEP can improve arterialoxygenation and dynamic lung compliance.