Postoperative Residual Neuromuscular Blockade And Intraoperative Muscle Relaxant Management In Thoracic Surgery

Background:Residual neuromuscular blockade is a common complication after muscle relaxant is used during general anesthesia.Studies have shown that incidence of postoperative residual muscle relaxant after general anesthesia was 3.5%⁸8%,and the incidence was57.8%after abdominal surgery.The incidence of RNMB in different researches have differences,but these figures show that the occurrence of RNMB is still high,which can lead to oxygen desaturation,reflux aspiration,lung atrophy,muscle weakness,acute respiratory failure and even death,the harm and influence factors have aroused much more concern and attention by anesthesiologists.There are many factors that can influence drug metabolism of muscle relaxant.Respiratory acidosis can extend the effect time of depolarizing muscle relaxant,so the insufficient ventilation will affect the recovery of neuromuscular junction function.Patients at low temperature,elderly patients,low potassium can slow metabolism of muscle relaxant,inhaled anesthetics may enhance the effect of muscle relaxant.The management of perioperative muscle relaxant should consider the presence of these factors,and grasp the drug delivery and drug withdrawal time reasonably.Thoracic surgery has characteristics of large trauma,long operation time,pain and postoperative complications.The intraoperative anesthetics can not only satisfy the requirements of the operation but also have impact on the patient's respiration and circulation.This puts forward more strict requirements of intraoperative drug management for anesthesiologists.Patients with the wound pain often lead to respiratory insufficiency after thoracotomy.Postoperative RNMB can not only delay the patients'recovery time,but also increase the incidence of pulmonarycomplications,andfurtheraggravatetherespiratory dysfunction.With the increase of muscle relaxant controllability,the muscle relaxant requirements by the surgeon become higher,and studies of neuromuscular blockade depth come into focus.Researches showed that deep muscle relaxant can reduce pneumoperitoneum pressure,expand the surgical field,greatly reduce intraoperative adverse events?body movement,coughing,diaphragmatic muscle movement?and the incidence of postoperative pain.Due to the scope of thoracic surgery involve the lung,trachea and diaphragm,the operation process often have the tracheal juga,trachea,bronchus stretch and lymph node cleaning,these excitant operation have significant impact on the respiratory and the cycle,and there are many great vessels,the patient's body movement,coughing,diaphragmatic muscle movement can have a great influence on the operation,poor operation view will extend the operation time and increase the risk of surgery.Regulate and contral the best neuromuscular blockade depth have important clinical significance for avoiding intraoperative adverse events.So what kind of monitoring should be adopted and what suitable depth should be maintained for thoracic surgery need further research.This study select patients with thoracic surgery under general anesthesia.our researches are as follows:1,The patients who finish the thoracic surgery are transferred into PACU immediately,statistic the incidence of RNMB at the time of extubation?TOF<90%?and analyze the risk factors that cause RNMB.2,Comparison of moderate neuromuscular blockade?TOF1²?and deep neuromuscular blockade?PTC1⁵?,comparing the incidence of adverse events and muscle relaxant satisfaction by the surgeon during the thoracic surgery.3,Dixon sequential method is adopted to study suitable continuous pumping speed of cisatracurium,in order to find the way of maintaining the target depth without the muscle relaxant monitoring.The above studies aim to reduce the incidence of RNMB after thoracic surgery and provide the theory basis for reasonable application of muscle relaxant.Methods:1.We select patients who were transferred to PACU immediately after thoracic surgery from March 2015 to September 2015.Record the TOFr when the patients entered into PACU and at the time of extubation,record the extubation time,the time that TOFr recovered to 90%after extubation,and record all the situation of recovery management.Through the above records and observed data,we statistic the incidence of RNMB after thoracic surgery and analyze its risk factors.2.Select elective 60 patients with thoracoscope lung surgery.Patients were randomly divided into deep group?PTC group,PTC1⁵?and moderate group?TOF group,TOF1²?.Maintain intraoperative muscle relaxant depth according to the group control,Record adverse events of two groups?body movements,coughing,spontaneous breathing?,muscle relaxant satisfaction by surgeon and recovery data.3.Select elective patients with thoracoscope lung surgery undergoing general anesthesia.Modified Dixon sequential method was adopted,the pump speed of the first patient was 0.12mg/kg/h,and monitored PTC and TOF continually.Observe the maintaining situation of muscle relaxant depth,in order to get 6 times threshold which straddles the median as the finish of the experiment,to calculate the continuous infusion speed of cisatracurium that can maintain 95%of the patients muscle relaxant depth1?PTC?5?ED95?.Results:1.The incidence of RNMB at the time of extubation after thoracic surgeries was 52.5%.Logistic regression analysis results showed that diabetes mellitus,intraoperative use of two kinds of muscle relaxants,average intraoperative cisatracurium dosage?0.14 mg·kg^-1·h^-1,TOFr?0.5 at the time of transferring to PACU,extubation time?30 min were independent risk factors for thoracic surgery patients?P<0.05?2.There were 52%patients in moderate group appearing adverse events and 32%patients that muscle relaxant satisfaction was evaluated as optimal,the average intraoperative cisatracurium dosage was 0.0741±0.0045mg/kg/h.No adverse events occurred in deep group and 72%patients that muscle relaxant satisfaction was evaluated as optimal,the averageintraoperativecisatracuriumdosagewas0.1223±0.0045mg/kg/h,thereweresignificantdifferencebetweentwo groups.While the time from antagonism to TOFr recovering to 90%and recovery index had no statistical significance between two groups.3.The continuous pump speed of cisatracurium dosage was 0.108mg/kg/h?95%CI:0.105⁰.125?that can maintain 1?PTC?5,The recovery index and recovery time had no significant difference between the patients that PTC?5 and PTC>5.Conclusion:1.The incidence of RNMB at the time of extubation after thoracic surgeries was 52.5%.The risk factors that can lead to RNMB should be avoided and close monitoring after extubation.2.Deep neuromuscular blockade?PTC1⁵?was appropriate depth for thoracic surgery,which can greatly reduce the incidence of intraoperative adverse events,improve the surgeon's muscle relaxant satisfaction,and will not affect postoperative patients recovery.3.The continuous pump speed of cisatracurium dosage was 0.108mg/kg/h?95%CI:0.105⁰.125?that can maintain1?PTC?5,this dose can be referred without the muscle relaxant monitoring,and meet 95%of the patients who can sustain 1?PTC?5 during the surgery.