Effect Of Deep Versus Moderate Neuromuscular Blockade On Surgical Conditions And Pulmonary Function In Laparoscopic Assisted Gastrectomy

Objectives To investigate the effects of deep and moderate neuromuscular blockade under general anesthesia（sevoflurane-intravenous balanced anesthesia）on surgical conditions and pulmonary function in laparoscopic assisted radical gastrectomy.Methods Forty patients undergoing laparoscopic gastrectomy from October8^th,2018 to February 28^th,2019 were randomly allocated to deep neuromuscular blockade group（group D）and moderate neuromuscular blockade group（group M）.Twenty patients in each group and they all received general anesthesia（sevoflurane-intravenous balanced anesthesia）.Cis-atracurium was used to maintain neuromuscular blockade.We adjusted the depth of neuromuscular blockade under the guidance of neuromuscular blockade monitor,so that Post tetanic count（PTC）in group D was less than 2 and Train-of-Four（TOF）in group M was 1².Arterial blood gas analysis was performed before operation（T₀）,before pneumoperitoneum（T₁）,pneumoperitoneum for 10 minutes（T₂）,pneumoperitoneum for 30 minutes（T₃）,pneumoperitoneum for 60 minutes（T₄）and 10 minutes after withdrawn of pneumoperitoneum（T₅）.Heart rate（HR）,mean arterial pressure（MAP）,mean airway pressure（Pmean）,pulmonary dynamic compliance（Cdyn）and inhaled oxygen concentration（FiO₂）were recorded at T₁-T₅.Pneumoperitoneal pressure was recorded every 30 minutes after the introduction of trocar,and surgical rating scale（SRS）was assessed every 30minutes until the cease of pneumoperitoneum.When the SRS score≤3,the intra-abdominal pressure was gradually increased by 2 mmHg under the condition that the neuromuscular blockade requirements of each group were met.We limited the range of IAP between 8 to 15mmHg.All patients were given a patient-controlled analgesia（PCIA）pump after surgery.Duration of pneumoperitoneum,total input,urine output,duration of operation,time to extubation,complications during postanesthesia care unit（PACU）stay,and the cases of pulmonary infection within3 days after operation were recorded.We also record the postoperative information,such as values of white blood cell（WBC）,c-reactive protein（CRP）,and neutrophils ratio（NE%）,length of hospital stay,etc.Results1 There were no significant differences in general condition,pulmonary function parameter,preoperative Partial pressure of oxygen in radial artery（PaCO₂）,CRP,WBC and NE%between the two groups（P>0.05）;all patients received laparoscopic gastrectomy without conversion to open surgery.2 The differences in HR and MAP between the two groups were not statistically significance（P>0.05）.3 The differences in pneumoperitoneal pressure and SRS were of statistical significance between the two groups（P<0.05）.Pneumoperitoneal pressure in group D was lower than that in group M,and SRS was higher than that in group M.Although the duration of operation time in group D was shorter than that in group M,the difference was not statistically significant（P>0.05）.4 Respiratory mechanics Compared with T₁,the level of Pmean increased and the Cdyn decreased during the process of pneumoperitoneum（T₂^T₄）（P<0.05）,but at time T₂^T₄,the change of Cdyn in group D were higher than in group M,and the change of Pmean in group D was less than in group M,and the differences were statistically significant（P<0.05）.There were no significant difference in the Pmean and Cdyn between T₁ and T₅ in both group M and group D（P>0.05）.Pmean and Cdyn returned to T1 levels at T5（P>0.05）.5 Oxygenation index（PaO₂/FiO₂）and respiratory index（RI）There was no statistical significance difference in PaO2/FiO2 and RI between the two groups（P>0.05）.Intra-group comparison:Compared with T₁,PaO₂/FiO₂ decreased and RI increased at T₂^T₅ in both groups,but the differences were of no statistical significance（P>0.05）.6 PACU stay Compared with group M,duration of PACU extubation time（from the patient enter the PACU to extubation）in group D was longer,but the difference was no statistical significance.There were 8 cases in group M and 3 cases in group D required paravertebral nerve block due to postoperative pain,the difference was not statistically significant（P>0.05）.There were 2 cases in group M and 4 cases in group D whose SPO₂ was lower than 90%after extubation in the PACU.The differences was not statistically significant（P>0.05）.And the conditions improved after nasal oxygen given.7 Postoperative outcomes There was no significant difference in CRP,WBC,NE%,time to fart and/or defecation,incidence of pulmonary infection within 3 days and length of hospital stay between the two groups（P>0.05）.Conclusion Deep neuromuscular blockade in laparoscopic assisted gastrectomy under general anesthesia（sevoflurane-intravenous balanced anesthesia）can provide more adequate operation space,improve operative conditions,increase operative surgical rating scale,improve lung dynamic compliance and decrease mean airway pressure.Although the effect of improving pulmonary oxygenation was limited,it did not increase the risk of pulmonary infection after operation,and did not affect the outcome and recovery quality of patients.