The Pharmacodynamics Of Injection Of Cisatracurium Base On Lean Body Mass Pattern To Maintain Deep Neuromuscular Blockade In Obese Patients

Objective:To observe the pharmacodynamics of intravenous infusion of cisatracurium（CIS）based on lean body mass pattern to maintain deep neuromuscular blockade in obese patients during laparoscopic colorectal surgery,and to explore a more suitable administration method for maintaining deep neuromuscular blockade in obese patients.Methods:One hundred and twenty patients with ASA I toⅢ,aged 18to 65 years who underwent elective laparoscopic colorectal surgery from March 2021 to June 2022 were enrolled in the study.They were divided into four groups according to the random number table method（n=30）:Normal weight patients according to lean body weight group（NL group）,normal weight patients according to real weight group（NR group）,obese patients according to lean body weight group（OL group）,and obese patients according to real weight group（OR group）.Post-tetanic count stimulation（PTC）was measured every 6 min in the four groups,and Intraoperative deep neuromuscular blockade（PTC≤2）was maintained in all four groups.When PTC was greater than 2,OR and NR groups were given0.05 mg/kg（1ED95）CIS calculated according to actual body weight;OL and NL groups were given 0.05 mg/kg（1ED95）CIS calculated according to the degreased body weight.After the operation,0.04mg/kg neostigmine and 0.02mg/kg atropine were given to the patient when the train-of-four stimulation ration（TOFr）reached 0.2.The tracheal catheter could be removed when the TOFr≥0.9,the patient was conscious,breathing was stable,the head up test and tongue pressure test were completed.The time to effect,the dosage of cisatracurium（additional dosage,total dosage）,the number of injections,average dosing interval time,time to recovery from TOFr,time to recover TOFr to 0.7 and 0.9,and time to stay in post anesthesia care unit（PCAU）were recorded.The surgeon’s satisfaction of the operative field with surgical rating scale（SRS）were recorded at the time of pneumoperitoneum establishment,1 hour and 2 hours after pneumoperitoneum establishment.The heart rate（HR）,mean arterial pressure（MAP）of four groups were recorded at the time of pre-operation（T₀）,immediately after intubation（T₁）,at the time of surgical skin-incision（T₂）,and 1 hour after the operation（T₃）.Mean pneumoperitoneum pressure,whether hypoxemia occurs after extubation,and whether it is known during operation are also recorded.A tongue depressor test was used to determine whether residual neuromuscular block occurred after surgery.Results:1.The sex, age and height among four groups were no significant differences（P>0.05）.There are differences in body weight and BMI between obese group and normal weight groups（P<0.05）.2.Recovery of neuromuscular blockade:（1）Compared with OL group,PACU retention time in OR group was significantly longer（P<0.05）.（2）The recovery time of TOFr in OR group was significantly longer than that in the other three groups,while that in OL group was not significantly longer（P<0.05）.（3）The recovery time of neuromuscular blockade in OL group was significantly shorter than that in OR group（P<0.05）.3.CIS usage condition:（1）The injection times was no significant difference（P>0.05）.（2）The dosage of CIS according to the lean body weight was significantly lower than that according to the total body weight（P<0.05）.（3）The average dosing interval of OR group was significantly longer than that of lean body weight（P<0.05）.The average dosing interval between OL group and normal weight group was no significant difference（P>0.05）.（4）The time to effect of obese patients was significantly shorter than that of normal weight patients,but the time from induction to the first dosing of obese patients was significantly longer（P<0.05）.4.surgery operation condition:There was no statistical difference in SRS scores of the four groups at the time of pneumoperitoneum establishment,1h and 2h after pneumoperitoneum establishment（P>0.05）;There was no statistical difference in mean pneumoperitoneum pressure during operation（P>0.05）.5.There were no hypoxemia after extubation,intraoperative awareness during operation and no postoperative residual neuromuscular block（PRNB）occurred in the enrolled patients.Conclusions:1.Maintaining deep neuromuscular blockade in obese patients based on lean body weight can reduce pneumoperitoneal pressure while achieving pharmacodynamics similar to actual body weight administration,and still meet surgical vision under low pneumoperitoneum pressure,reducing complications caused by high pneumoperitoneum pressure.2.Maintaining deep neuromuscular blockade in obese patients based on lean body weight can shorten neuromuscular blockade recovery time and stay time in PACU,and no PRNB has occurred.3.Maintaining deep neuromuscular blockade in normal patients based on lean body weight cannot shorten neuromuscular blockade recovery time and stay time in PACU.