Effect of open-lung ventilation strategy on oxygenation-impairment during laparoscopic colorectal cancer resection
	    		
		   		
		   			
		   		
	    	
    	 
    	10.3760/cma.j.issn.441530-20191209-00507
   		
        
        	
        		- VernacularTitle:肺开放通气策略对腹腔镜结直肠癌手术中氧合障碍的影响
 
        	
        	
        	
        		- Author:
	        		
		        		
		        		
			        		Hong LI
			        		
			        		
			        		
			        			1
			        			
			        		
			        		
			        		
			        		
			        		;
		        		
		        		
		        		
			        		Jing GUO
			        		
			        		;
		        		
		        		
		        		
			        		Kai WANG
			        		
			        		;
		        		
		        		
		        		
			        		Nanrong ZHANG
			        		
			        		;
		        		
		        		
		        		
			        		Zhinan ZHENG
			        		
			        		;
		        		
		        		
		        		
			        		Sanqing JIN
			        		
			        		
		        		
		        		
		        		
		        		
		        			
			        		
			        		Author Information
			        		
		        		
		        		
			        		
			        		
			        			1. 中山大学附属第六医院麻醉科,广州 510655
			        		
		        		
	        		
        		 
        	
        	
        	
        	
        		- Keywords:
        			
	        			
	        				
	        				
			        		
				        		Colorectal neoplasms;
			        		
			        		
			        		
				        		Laparoscopic surgery;
			        		
			        		
			        		
				        		Low-tidal-volume ventilation;
			        		
			        		
			        		
				        		Open-lung strategy;
			        		
			        		
			        		
				        		Oxygenation-impairment
			        		
			        		
	        			
        			
        		
 
        	
            
            
            	- From:
	            		
	            			Chinese Journal of Gastrointestinal Surgery
	            		
	            		 2020;23(11):1081-1087
	            	
            	
 
            
            
            	- CountryChina
 
            
            
            	- Language:Chinese
 
            
            
            	- 
		        	Abstract:
			       	
			       		
				        
				        	Objective:After general anesthesia and mechanical ventilation for laparoscopic colorectal cancer resection, about 90% of patients would have different degrees of atelectasis. Authors speculated that an open-lung strategy (OLS) comprising moderate positive end-expiratory pressure (PEEP) and intermittent recruitment maneuvers (RM) can reduce atelectrauma and thus reduce the incidence of oxygenation-impairment during low-tidal-volume ventilation for laparoscopic colorectal cancer resection. The purpose of this study was to verify this hypothesis and provide a better intraoperative ventilation scheme for laparoscopic colorectal cancer resection.Methods:This was a prospectively randomized controlled clinical trial which was approved by the Ethics Committee of the Sixth Affiliated Hospital, Sun Yat-sen University (2017ZSLYEC-002), and registered at the ClinicalTrials.gov (NCT03160144). From January to July 2017, patients who underwent laparoscopic colorectal cancer resection, with age > 40 years, estimated pneumoperitoneum time ≥ 1.5 h, pulse oxygen saturation ≥ 92%, and risk grade for postoperative pulmonary complications ≥ 2 were prospectively enrolled. The patients with American Society of Anesthesiologists physical status ≥ IV, body mass index ≥ 30 kg/m 2, pneumonia, acute respiratory failure or sepsis within 1 month, severe chronic obstructive pulmonary disease, pulmonary bullae and progressive neuromuscular diseases, and those participating in other interventional clinical trials were excluded. The enrolled patients were randomly assigned (1:1) to the OLS group (with a PEEP of 6-8 cm H 2O and intermittent RM), and the NOLS group (without using PEEP and RM). Partial pressure of arterial oxygen (PaO 2) /fraction of inspired oxygen (FiO 2) and shunt fraction (Q S/Q T) were calculated via arterial and central venous blood gas analysis performed at 0.5 h (T 1), 1.5 h (T 2) after pneumoperitoneum induction and at 20 min after admission to the recovery room. Driving pressure immediately before pneumoperitoneum induction (T 0) and at T 2 were calculated via monitoring data. The primary outcome was oxygenation-impairment (PaO 2/FiO 2 ≤ 300 mmHg) during mechanical ventilation. Results:In each group, 48 patients under general anesthesia and low-tidal-volume ventilation were included in the final analysis. During ventilation, the oxygenation-impairment occurred in 7 patients (14.6%) of OLS group and in 17 patients (35.4%) of NOLS group, whose difference was statistically significant between two groups (χ 2=5.556, RR=0.31, 95%CI: 0.12 to 0.84, P=0.033). During ventilation, the patients in the OLS group had higher PaO 2/FiO 2 [T 1: (427±103) mmHg vs. (366±109) mmHg, t=-2.826, P=0.006; T 2: (453±103) mmHg vs. (388±122) mmHg, t=-2.739, P=0.007], lower Q S/Q T [ T 1: (9.2±6.5) % vs. (12.6±7.7) %, t=2.322, P=0.022; T 2: (7.0±5.8)% vs.(10.9±9.2)%, t=2.408, P=0.019], and lower driving pressure [T 0: (6±3) cm H 2O vs. (10±2) cm H 2O, t=7.421, P<0.001; T 2: (13±3) cm H 2O vs. (17±4) cm H 2O, t=5.417, P<0.001] than those in the NOLS group, with stratistical differences in all comparisons. In recovery room, though PaO 2/FiO 2 [(70.3±9.4) mmHg vs. (66.8±9.4) mmHg, P=0.082] was still higher and Q S/Q T [(18.6±8.3)% vs. (21.8±8.4)%, P=0.070] was still lower in the OLS group as compared to the NOLS group, the differences were not statistically significant (both P>0.05). Conclusion:The application of such an OLS during low-tidal-volume ventilation can greatly reduce the incidence of oxygenation-impairment in laparoscopic colorectal cancer resection, and such effect may last to the period of emergence from anesthesia.