Effects Of Domestic Rocuronium Given By Different Methods On Muscle Relaxation In Patients Undergoing Esophagectomy

Background:Application of muscle relaxants is an important link to the induction of anesthesia and intubation and maintain anesthesia, but now the commonly used depolarizing muscle relaxant, can cause effects such as increased IOP and bradycardia. Non-depolarizing muscle relaxants, almost all there is a slow onset, strong role of histamine release and hemodynamic changes. Rocuronium as a new steroid muscle relaxant almost without histamine release, and restore quickly and very little accumulation. Rocuronium light cardiovascular effects , good stability, can cause mild increase in heart rate and small hemodynamics changes. Target controlled infusion (TCI) which is recently developed a new type of drug delivery by intravenous, is a combination of pharmacokinetics and computer technology, as an intravenous drug delivery. Propofol and Midazolam on the studies of pharmacodynamics indicated that controlling the depth of anesthesia by TCI is better than the manual way of continuous infusion by micro pump. In current, It was gradually increased that TCI was used at home and abroad to study aspects of muscle relaxants, but there was very little study for rocuronium in thoracic surgery by TOF monitoring. We study the superiority by TCI for rocuronium in thoracic esophageal cancer patients and whether it is superior than the classic intermittent administration.Objective:To observe the muscle relaxation effects of rocuronium given by intermittent input and target controlled infusion in patients undergoing esophagectomyand provide references for about how to apply muscle relaxants reasonably. Through comparing the characteristics inpharmaco- dynamics of domestic rocuronium given by TCI and intermittent input, this study investigates the feasibility, advantages and disadvantages of rocuronium given by TCI. Methods:60 esophageal cancer patients for elective, 34 males and 26 famales ,aged 38～64yr, ASAⅠ～Ⅱ, body mass index (BMI)<30, without significant damages on heart, lung, liver, kidney, without any neuromuscular disease;with a good nutritional status and normal temperature, without anemia, hypoproteinemia,and electrolyte imbalance, and without receiving drugsof neuromuscular blockage before two weeks of surgery. All the patients were randomly divided into two groups, group RI (n = 15)was bolus injection at 0.6 mg/kg(2ED95)to induce with anesthesia, and appended at 0.3 mg/kg when T1=3%; Group RT (n = 45), anesthesia was induced with rocuronium given by TCI at 3.0μg/ml plasma concentration.All the 45 patients were divided into groups RT0.8, group RT1.0 and group RT1.2 (n = 15)according to the target plasma concentration(Ce) of rocuronium in the maintenance of anesthesia, the separate Ce was 0.8,1.0,1.2μg / ml. All patients was monitored with non-invasive arterial blood pressure (BP), electrocardiogram (ECG), pulse oxygen saturation (SpO2), end-tidal pressure of carbon dioxide (PETCO2) and bispectral index (BIS). On arrival of the patient at the operating room, patients were connected TOF-WATCHS accelerometer,and Ringer's solution 10ml /kgï¹’h was input intravenously from the contralateral upper extremity venous access,then atropine 0.5mg. Total intravenous anesthesia( TIVA) was used for both induction and maintenance of anesthesia. Induction of anesthesia: Fentanyl 4μg/kg was input intravenously. Propofol was input by TCI at concentration of 3μg/ml, until patients lost consciousness. Then all patients was monitored by the stimulation with four clusters, adjusting the first TOF twitch response (T1) at 100% as control value(Three continuous T1was always 100%), Group RI was input rocuronium 0.6mg/kg, group RT was target controlled infusion rocuronium at 3.0μg/ml, by a TCI pump with the model of Szenohradszkay pharmacokinetic (CTN-TCI-I single TCI pump:East Cheng Yi Tong Science Center in Beijing).The Ce of RT_0.8,RT_1.0,RT_1.2was set to 0.8,1.0,1.2μg / ml to maintain the anesthesia. When T1≤5% the tracheal intubate was performed, then the patients were mechanically ventilated after successful intubation, and PETCO2 was maintained among 30～40 mmHg. Maintenance of anesthesia: Anesthesia was maintained with TCI of propofol and remifentanil. Patients received no antagonists for reversal of neuromuscular blockade and recovered spontaneously .Neuromuscular blockade monitoring ended when T1≥75 %. The patients were extubated when ventilation was satisfactory. Record: 1)Heart rate(HR) and mean arterial pressure(MAP)in four groups at the time of before induction of anesthesia (t1), after induction of anesthesia (t₂), after input rocuronium until T₁ = 5æ—¶(t3), immediately after intubation (t₄),and after intubation 5min (t₅).2 ) The intubation conditions according Copper's score,onset time of rocuronium (S1), the amount of induction(W_i).3) Recovery index (S₂),the time when T1 restored to 75%(S₃), the average of rocuronium dosage(W_a)and the percentage of muscle relaxation.4) Observed the patients had a skin flushing, rash, bronchospasm and laryngeal edema or not.Results:1 There were no significant difference in Age, sex composition ratio, body mass index (BMI), hemoglobin and albumin.2 There was significant difference in HR and MAP when induction of anesthesia (t₂),and after input rocuronium until T1=5(t₃)compared with before induction of anesthesia (t₁)(P<0.05). There was no significant difference between input rocuronium until T1=5(t₃) and induction of anesthesia (t₂) in HR and MAP(P>0.05),but the HR and MAP was increased at immediately after intubation (t₄) compared with before induction of anesthesia (t₁)(P<0.05).There was no significant difference after intubation 5min (t₅) compared with before induction of anesthesia (t₁)(P>0.05).3 There was no difference in the intubation conditions according Copper's score among four groups(P>0.05),but in the onset time of rocuronium (P<0.05). There was no significant difference among Wi(P>0.05).4 There was significant difference among four groups in S₃(P<0.05),but no difference in recovery index (P>0.05). There was significant difference among four groups among Wa(P<0.05),and difference in muscle relaxation among RT_0.8,RT_1.0,RT_1.2and RT_0.8(P<0.05).5 We observed the patients did not have a skin flushing, rash, bronchospasm and laryngeal edema.Conclusions:1 Target controlled infusion of rocuronium in esophadeal cancer patients undergoing elective surgery was the more appropriate way, which achieved the same effect as the intermittent administration of muscle relaxant under the conditions of saving the amount of muscle relaxants, which avoid complications caused by excessive.2 TCI rocuronium is not suitable for induction of anesthesia. Increased the amount of rocuronium, recovery time increased, but no change in the recovery index.