| Background and ObjectiveMechanical ventilation is a kind of basic processes for maintaining respiratory support to the ICU critical patients or the patients with general anesthesia in the operating room. But unreasonable mechanical ventilation can lead to a variety of pathophysiological changes, thus cause ventilator-associated lung injury( VALI).Esophageal cancer is one of high incidence of malignant tumors in our country. Currently, surgery is still the main method for the treatment of esophageal cancer; but the incidence of postoperative pulmonary complications higher, and become the main factor that influence the postoperative survival and the life quality of patients. In the esophageal cancer surgery, it is often necessary to implement the one-lung ventilation( OLV), and most of patients are the elderly people whose respiratory function have degenerative changes, which easily lead to VALI. To preventing postoperative pulmonary complications is the key of perioperative management and treatment.The lung protective ventilation strategy( LPVS) is mean to use the small tidal volume, limit the Pplat, reasonably use the PEEP and permit the certain range of hypercarbia. In recent years, the mode of pressure controlled ventilation has gained attention anew. Currently, LPVS has been widely accepted and used on those critical patients of ICU by clinical doctors, no matter whether having lung damage in advance. But for those patients undergoing general anesthesia in the operating room, especially when implementing OLV in thoracic surgery, the lung protective ventilation strategy has not cause the attention of the clinicians and been controversial.This study mainly investigated the effect of LPVS on the pulmonary ventilation and exchange function and postoperative pulmonary complications during OLV, that we should choose what kind of mechanical ventilation mode( volume controlled ventilation or pressure controlled ventilation) and how to individually determine PEEP value according to P-V ring to meet the clinical demand and reduce postoperative pulmonary complications.Materials and Methods300 cases of patients undergoing the elective left thoracotomy esophageal cancer radical surgery were divided into six groups according to the random number table. The volume controlled ventilation group: group VA, group VB and group VC; and the pressure controlled ventilation group: group PA, group PB and group PC. PEEP= 0 cm H2 O for the group VA and PA; PEEP=PLIP- 2 for the group VB and PB; PEEP= PLIP + 2 for the group VC and PC. After the anesthesia induction and intubation for patients in a unified way, continuously recording three pressure-volume rings on the monitor( P- V ring), and take the average of three low inflection points as PLIP. Gather the arterial blood of patients for blood gas analysis before lateral position and OLV( T0) and 60 mins after the OLV( T1), and record Ppeak, Pplat, PETCO2, CL of patients at the same time, then record the time of pulling out the endotracheal tube at the end of the surgery. Calculate the Qs/Qt, Vd/Vt and RI at the corresponding time point according to the measurement results. Follow up the patients at 24 h after surgery for making pain score, gathering the arterial blood of patients for blood gas analysis and calculating respiratory index; Record the incidence rate of postoperative pulmonary complications, the rate of living in respiratory ICU and hospital stays.Statistical analysisAll results were statistically analysed by SPSS version 20.0 software. All values in line with the normal distribution were expressed as mean±SD. Difference between two groups is analyzed by t-test. One-way ANOVE was used for comparing different groups, LSD method was used for pairwise compatrison. Count data were compared usingX2 test or Fisher Exact Test. Levels of signficance test was α = 0.05.Results1. The comparison of Qs/Qt, Vd/Vt, RI and CLThe Qs/Qt, Vd/Vt and RI among six groups of patients were significantly higher at T1 than those at T0( P < 0.05), while CL was significantly lower( P < 0.05). The Qs/Qt, Vd/Vt and RI among group VB and VC at T1 were lower than those in group VA( P < 0.05), while CL was higher( P < 0.05). The Qs/Qt, Vd/Vt and RI among group PB and PC at T1 were lower than those in group PA( P < 0.05), while CL was higher( P< 0.05); The group PB significantly changed( P < 0.05). The Qs/Qt, Vd/Vt and RI in group PA at T1 were lower than those in group VA( P < 0.05), while CL was higher( P < 0.05); The Qs/Qt, Vd/Vt and RI in group PB at T1 were lower than those in group VB( P < 0.05).2. The comparison of Ppeak and PplatThe Ppeak and Pplat among six groups of patients were significantly higher at T1 than those at T0( P< 0.05). The Pplat in group VC at T1 were higher than that in group VA( P < 0.05). The Ppeak and Pplat among group PA and PB were lower than those in group PC( P < 0.05). The Ppeak in group PA was lower than that in group VA( P < 0.05); the Ppeak in group PB was lower than that in group VB( P < 0.05);the Ppeak in group PC was lower than that in group VC( P < 0.05).3. The comparison of the postoperative extubation time and RI after 24 hour of postoperationThe postoperative extubation time among the group VB and VC was shorter than that in group VA, and RI was lower( P < 0.05). The extubation time among the group PB and PC was shorter than that in group PA, and RI was lower( P < 0.05), and the group PB shortened and lowed obviously( P < 0.05). The postoperative extubation time in the group PA was shorter than that in group VA, and RI was lower( P < 0.05); the postoperative extubation time in the group PB was shorter than that in group VB, and RI was lower( P < 0.05).4. The comparison of incidence rate and Severity of postoperative pulmonary complicationsThe rate of postoperative pulmonary complications and hospital stay among the group VB and VC were lower than that in group VA( P < 0.05); the rate of postoperative pulmonary complications and hospital stay among the group PB and PC were lower than that in group PA( P < 0.05); the rate of postoperative pulmonary complications and hospital stay in the group PA was lower than that in group VA( P < 0.05). 4 cases checked in ICU in group VA, while 0 case in group VB and VC, thus the group VA was higher than the group VB and VC( P < 0.05); 1 case in group PA and PC, 0 case in group PB; the group VA was higher than the group PA( P < 0.05). 6 cases were not extubated or intubated again in group VA, while 1 case in group VB and VC, thus the group VA was higher than the group VB and VC( P < 0.05); 3 cases in group PA, 0 case in group PB, 1 case in group PC, thus the group PA was higher than the group PB and PC(P < 0.05); The group VA was higher than the group PA( P < 0.05). This study found no postoperative pulmonary complications leading to death.ConclusionDuring one-lung ventilation, it is reasonable when PEEP is PLIP- 2 cmH2 O. And pressure controlled ventilation mode is good for the function of intraoperative pulmonary ventilation and exchange. |
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