Effect Of Low Tidal Volume Ventilation Strategy On Blood Loss During Laparoscopic Hepatectomy

Research background:Liver cancer is an serious disease that threatens human health.Laparoscopic liver resection?LLR?is increasingly used for liver surgery including liver cancer resection since the first use of laparoscopic technique for partial hepatectomy in 1991,Reich et al¹.because of the advantages of small trauma,rapid postoperative recovery,safe and effective laparoscopic liver resection^2-9.However,the liver tissue is extremely fragile,rich in blood sinus,complicated in the distribution of blood vessels in the liver,making the blood loss of the wound in the surgical operation increasing and difficulty in laparoscopic exposure.Therefore,reducing blood loss and blood transfusion is related to surgery key factors for success and outcome.^10,11 According to reports in the literature,it is now proven that effective methods for controlling bleeding during such surgery include instrumental innovation,optimal pressure of pneumoperitoneum,and control of the hepatic inflow system and outflow system¹².Recent studies have shown that lowering airway pressure can also reduce the bleeding in open liver resections.However,it is unclear whether a low tidal volume ventilation strategy that reduces airway pressure can reduce the bleeding during laparoscopic hepatectomy^13.Therefore,this study used a prospective,randomized,controlled trial to investigate the effect of low tidal volume ventilation strategy on blood loss and perioperative pulmonary complications.Provides the optimal clinical decision for this type of surgery to reduce intraoperative blood loss.Objectives:84 patients were enrolled eligibly into the study and randomly assigned to receive either mechanical ventilation with low tidal volume?LTV??n=42?or conventional tidal volume?CTV??n=42?.The total blood loss during surgery and the incidence of perioperative pulmonary complications and postoperative liver and kidney function were compared between the two groups.To investigate whether mechanical ventilation with low tidal volume reduces surgical bleeding and satisfied intraoperative gas exchange during laparoscopic liver resection?LLR?.Methods:This is a prospective,randomized,single-blind study.Of the 84 patients randomized at a ratio of 1:1 to the LTV group and CTV group.and allocated to receive either mechanical ventilation with lower tidal volume?6⁸ ml/kg?along with recruitment maneuver?once/30minutes??the LTV group?or conventional tide volume?10¹2 ml/kg??the CTV group?during parenchymal resection.Patients were monitored for ECG,NBP,and SpO₂after entering the operating room.Systolic pressure,diastolic blood pressure,mean arterial pressure,cardiac output index,central venous pressure,stroke variability were collected at5 time points,such as before anesthesia intubation,15 min after intubation,before cutting the liver,during cutting the liver,and when the abdomen was closed.Blood loss per cm² of cutting surface of excision tumor?ml/cm²?during parenchymal resection,and postoperative pulmonary complications were assessed.Finally,The total blood loss and transection related blood loss?TRBL?was calculated.Statistical analyses were done on SPSS19.0 software?SPSS Inc.,Chicago,IL,USA?with two-tailed tests wherever appropriate and P values less than 0.050 were considered to be of statistical significanc.Results:1.80 patients were enrolled eligibly into finally analysis.Total blood loss in the LTV and CTV groups was 301.9 ml?35.0-780.0?and 394.3 ml?107.2-2135.1?ml,P<0.05.The mean blood loss per cm² of the resection surface in the LTV group was significantly lower than the CTV group[5.53 ml/cm²?1.88-12.80?vs 12.15 ml/cm²?2.05-38.13?,P<0.05.]2.The speed of parenchymal resection was enhanced in the LTV group compared with that in the CTV group[0.62 cm²/min?0.15-2.58?vs 0.53?0.10-2.58?,P<0.05].Surgeon satisfaction rating was increased in the LTV group than the CTV group[4?2-5?vs 3?2-4?,P<0.05].Two patients in CTV group underwent conversion to open hepatectomy because of uncontrolled bleeding from cutting surface?P>0.05?.3.Two patients in LTV group and eight patients in CTV group received blood transfusions during the surgery?P<0.05??Table 2?.Five patients in the CTV group and no patient in the LTV group received nitroglycerin to lower CVP?P<0.05?.4.Respiratory infection occurred in two patients in both groups,respectively?2/40 vs2/40,P=1.000?.Atelectasis that need for invasive ventilation,all causes mortality in hospital stay and six month after operation were not found difference in both groups.There was no significant difference in duration of ICU stay[17.4 h?10.7-57.6?vs 17.6 h?10.9-68.6?,P>0.05)and hospital stay?15.5 d?7.0-29.0?vs 16.0 d?7.0-33.0?,P>0.05?between two groups.Three patients in LTV group,four patients in STV group were readmitted hospital beyond six months after surgery?P>0.05?Conclusion:1.Compared with conventional tidal volume,the low tidal volume ventilation strategy can effectively reduce the amount of bleeding during LLR.It also provide surgeons with a clearer field of surgery.At the same time,it can reduce blood transfusion,reduce the amount of vasoactive drugs,and reduce the incidence of intraoperative hemodynamic abnormalities in such patients.2.Compared with conventional tidal volume,the low tidal volume ventilation strategy does not increase the incidence of postoperative pulmonary complications in this type of patients.