The pharmacoeconomics of neuromuscular blocking drugs: a perioperative cost-minimization strategy in children

The purpose of this investigation was to compare the costs of intermediate-acting neuromuscular blocking drugs in children during routine ambulatory surgery. We studied 200 healthy, 2-10-yr-old children undergoing elective dental restorative surgery. During Part 1 of the study, children received an inhaled anesthetic with halothane and nitrous oxide, whereas in Part 2, the anesthetic was IV propofol with nitrous oxide. The study drugs were atracurium, cisatracurium, mivacurium, rocuronium, and vecuronium. Patients were initially administered 2x the effective dose for 95% of the study drug. After recovery to 10% of baseline neuromuscular function, the neuromuscular blockade was rigidly maintained with an infusion of the study drug at about 10% of baseline function. Neuromuscular drug costs were approximated as drug usage x cost/unit. The initial drug costs were not substantially different for both Parts 1 and 2, but over time, mivacurium became the most expensive drug and cisatracurium the least expensive. In conclusion, based on current costs, cisatracurium is the least expensive intermediate-acting neuromuscular drug. IMPLICATIONS: For children undergoing minor ambulatory procedures of 1-2 h, and continuous intraoperative neuromuscular blockade is indicated, cisatracurium currently is the least expensive drug.     

Large bolus dose vs. continuous infusion of cisatracurium during hypothermic cardiopulmonary bypass surgery

BACKGROUND AND OBJECTIVE: We investigated whether a high bolus dose of cisatracurium (8x ED95) given at induction can provide muscle relaxation for the major part of a cardiac procedure with hypothermic cardiopulmonary bypass, avoid important postoperative residual curarization and cause no waste of product. METHODS: Twenty patients were randomly assigned either to Group 1 (n = 10) or Group 2 (n = 10). Those in Group 1 were given cisatracurium in a high bolus dose (0.4 mg kg(-1)). Those in Group 2 received cisatracurium 0.1 mg kg(-1) at induction followed after 30 min by a continuous infusion of cisatracurium. As an escape medication in case of patient movement, a bolus dose of cisatracurium 0.03 mg kg(-1) was given. RESULTS: In Group 1 (large cisatracurium bolus dose), the clinical duration of effect (until T1/T0 = 25%) was 110 min. Six of 10 patients in Group 1 required additional boluses of cisatracurium intraoperatively. Four of these six had received an additional bolus near the end of surgery and had a train-of-four (TOF) ratio = 0 at the end. The other four patients in Group 1 had a final TOF ratio >0.9. In Group 2 (continuous cisatracurium infusion), only two patients had a TOF ratio >0.9 at the end of surgery, no patient moved and none received additional boluses. The total amount of cisatracurium used in the bolus and infusion Groups was 34.5 +/- 7.8 and 21.3 +/- 5.7 mg, respectively (P = 0.0004). CONCLUSIONS: For continued neuromuscular block during hypothermic cardiac surgery, a high bolus dose of cisatracurium appears to be safe, although it is not an alternative to a continuous infusion, as its neuromuscular blockade does not cover the intraoperative period and a high incidence of movements occurs. In the patients who received a high bolus dose of cisatracurium, postoperative residual curarization appeared after additional boluses had been given. The consumption of cisatracurium by high bolus was significantly greater than with continuous infusion.     

Cisatracurium-induced neuromuscular blockade is affected by chronic phenytoin or carbamazepine treatment in neurosurgical patients

The effect of chronic anticonvulsant therapy (CAT) on the maintenance and recovery profiles of cisatracurium-induced neuromuscular blockade has not been adequately studied. In this study, we compared the pharmacokinetics and pharmacodynamics of cisatracurium after a prolonged infusion in patients with or without CAT. Thirty patients undergoing intracranial surgery were enrolled in the study: 15 patients under CAT (carbamazepine and phenytoin, Group A) and 15 controls receiving no anticonvulsant therapy (Group C). Anesthesia was standardized and both groups received a bolus of cisatracurium followed by an infusion to maintain a 95% twitch depression. A steady-state was obtained and the infusion was kept constant for 2 additional hours. Neuromuscular blockade was then allowed to spontaneously recover. Blood samples were taken for measurement of cisatracurium plasma concentration during the steady-state period (Cp(ss)95) and at various times during recovery. Demographic and intraoperative data were similar. CAT resulted in faster 25% and 75% recovery of the first twitch. The rate of infusion of cisatracurium needed to maintain a 95% twitch depression at steady-state was 44% faster in Group A (P < 0.001). The clearance of cisatracurium was significantly faster in Group A when compared with Group C (7.12 +/- 1.87 versus 5.72 +/- 0.70 L . kg(-1) . min(-1), P = 0.01). The Cp(ss)95 was also significantly larger in Group A (191 +/- 45 versus 159 +/- 36 ng/mL, P = 0.04). In addition, patients receiving CAT had a 20% increase in the clearance of cisatracurium that, in turn, resulted in a faster recovery of neuromuscular blockade after an infusion of the drug. Also, patients under CAT had a 20% increase in their Cp(ss)95, indicating an increased resistance to the effect of cisatracurium.     

Cisatracurium in cardiac surgery--continuous infusion vs. bolus administration

The aim of this study was the comparison of infusion vs. intermittent bolus administration of cisatracurium (CA) following cardiac surgery with regard to total intraoperative dose and time of recovery from neuromuscular blockade. From June 2005 to April 2006 sixty ASA II-III patients who were undergoing coronary bypass graft and valve replacement surgery, were equally divided and randomized to receive either intermittent bolus (Group A, n = 30) or continuous infusion (Group B, n = 30) of CA in Madani Heart Center in the Tabriz (Iran). Total intraoperative dose of CA and time to TOF ratio = 0.8 after operation were measured. Anesthesia technique in two groups was the same. All of the patients underwent cardiopulmonary bypass. Intensity of neuromuscular blockade maintained on one train-of-four (TOF) twitch response of adductor pollicis during operation. Mean received dose of CA was 32.8 +/- 20.6 micro/kg/hr in Group A and 89.7 +/- 39.4 micro/kg/hr in Group B (p = 0.003). Total intraoperative dose of CA was 23.6 +/- 4.9 mg in Group A and 39.2 +/- 10.1 mg in Group B (p = 0.001). Spontaneous recovery from neuromuscular blockade in ICU (TOF ratio = 0.8) was reached in 43.8 +/- 9.2 min in Group A, and 64.2 +/- 15.1 min in Group B (p = 0.0001). Intubation time in ICU was not significantly different (Group A = 8.3 +/- 5.1 hrs vs. Group B = 10.2 +/- 6.2 hrs, p = 0.256). These results support the intermittent bolus administration of cisatracurium in cardiac surgery following cardiopulmonary bypass.     

Cisatracurium pharmacokinetics and pharmacodynamics during hypothermic cardiopulmonary bypass in infants and children

Background: Hypothermia potentiates neuromuscular blockade in adults during cardiopulmonary bypass (CPB) but the pediatric literature is sparse. Temperature‐dependent Hoffman degradation of cisatracurium may allow reduction in infusion rate (IR) during hypothermia. The effect of hypothermic CPB on the pharmacokinetics (PK) and pharmacodynamics (PD) of cisatracurium has not been described in children. Methods and materials: Using neuromuscular monitoring with a Datex Relaxograph, cisatracurium IR was adjusted to obtain a pseudo‐steady state during each phase of surgery (pre‐CPB, CPB, post‐CPB). Paired samples were taken at each phase. Cisatracurium plasma concentrations (Cpss) were determined by HPLC. Core and skin temperatures were recorded. Results: Data from ten infants were analyzed: Group 1: mean 33.6°C; Group 2: mean 21.9°C. To maintain T1% between 5% and 10% in Group 2, the IR was decreased by a mean of 89% (P < 0.001). IR was not significantly different in Group 1. Post‐CPB IR approximated pre‐CPB rates in both groups. During CPB, Cpss fell by 27% in Group 1 and by 50% in Group 2 (P = 0.039). Post‐CPB Cpss was not significantly different to pre‐CPB in either group. Clearance did not change significantly in Group 1 but fell significantly in Group 2 during CPB (P = 0.002). Clearance post‐CPB was unchanged from pre‐CPB. Conclusions: Cisatracurium IR may be decreased by around 60% during CPB with moderate hypothermia but can be maintained at baseline during mild hypothermia.     

Postoperative residual curarization with cisatracurium and rocuronium infusions

BACKGROUND AND OBJECTIVE: Monitoring of neuromuscular blockade still often relies on clinical judgement. Moreover, there are substantial national differences in the use of agents to 'reverse' their effects. We investigated the recovery characteristics and incidence of postoperative residual curarization after cisatracurium and rocuronium infusions for long duration interventions without systematic antagonism. METHODS: In 30 patients undergoing major surgery, we measured infusion dose requirements for rocuronium and cisatracurium during propofol anaesthesia. Infusions were discontinued at the beginning of surgical closure; spontaneous recovery of neuromuscular function was awaited in both groups. Neostigmine (50 microg kg(-1)) was administered only when a patient started to wake without a train-of-four ratio (TOF) of 0.9. RESULTS: In the cisatracurium and rocuronium groups, four (27%) and one (7%) patients, respectively, had a TOF ratio > or = 0.9 at the end of surgery. The TOF ratio in each group at that time was 51 +/- 32% for cisatracurium and 47 +/- 31% for rocuronium (P = 0.78). Six patients (40%) in the cisatracurium group and seven (47%) in the rocuronium group required neostigmine. The TOF ratio at the time of reversal was 63 +/- 7% for cisatracurium and 40 +/- 19% for rocuronium (P = 0.01). The time interval between the end of surgery and a TOF ratio of 0.9 was 10 +/- 9 min for cisatracurium and 18 +/- 13 min for rocuronium (P = n.s.). CONCLUSIONS: Patients receiving a cisatracurium or rocuronium infusion have a high incidence of postoperative residual curarization when the block is not antagonized. When 'reversal' is not attempted, cisatracurium seems to be safer than rocuronium.     

Desflurane reduces the effective therapeutic infusion rate (ETI) of cisatracurium more than isoflurane, sevoflurane, or propofol

PURPOSE: The present study investigated the interaction between the cumulative dose requirements of cisatracurium and anesthesia with isoflurane, sevoflurane, desflurane or propofol using closed-loop feedback control. METHODS: Fifty-six patients (18-85 yr, vitrectomies of more than one hour) were studied. In the volatile anesthetics groups, anesthesia was maintained by 1.3 MAC of isoflurane, sevoflurane or desflurane; in the propofol group, anesthesia was maintained by a continuous infusion of 6-8 mg.kg(-1).hr(-1) propofol. After bolus application of 0.1 mg.kg(-1) cisatracurium, a T1%-level of 10% of control level (train-of-four stimulation every 20 sec) was maintained using closed-loop feedback controlled infusion of cisatracurium. The effective therapeutic infusion rate (ETI) was estimated from the asymptotic steady-state infusion rate Iss. The Iss was derived from fitting an asymptotic line to the measured cumulative dose requirement curve. The ETI of the different groups was compared using Kruskal-Wallis- test, followed by rank sum test, corrected for the number of comparisons, P <0.05 was regarded as showing significant difference. RESULTS: ETI in the isoflurane group was 35.6 +/- 8.6 microg.m(-2).min(-1), in the sevoflurane group 36.4+/- 11.9 microg m(-2).min(-1), in the desflurane group 23.8 +/- 6.3 microg.m(-2).min(-1). The ETI of the volatile anesthetic groups were all significantly lower than the ETI in the propofol group at 61.7 +/- 25.3 microg.m(-2).min(-1) (P <0.002). The ETI in the desflurane group was significantly lower than in all other groups (P <0.02). CONCLUSION: In comparison to propofol, isoflurane, sevoflurane and desflurane reduce the cumulative dose requirements of cisatracurium to maintain a 90% neuromuscular blockade by 42%, 41% and 60%, respectively.     

腹腔镜手术中持续输注与间断静注顺式阿曲库铵维持深度肌松的药效学比较

目的探讨持续输注顺式阿曲库铵维持深度肌松在腹腔镜手术中的有效性和安全性。方法择期行腹腔镜辅助胃肠道肿瘤根治术患者60例,年龄18~65岁,随机分为A、B两组,每组30例。A组使用顺式阿曲库铵0.15 mg/kg诱导插管,并在强直刺激后计数(post tetanic count,PTC)恢复至≥3时以初始速率0.2mg·kg-1·h-1开始泵注,术中维持肌松深度在PTC≤2。B组使用顺式阿曲库铵0.15mg/kg诱导插管,并在每次PTC恢复至≥3时间断追加0.05mg/kg,术中维持肌松深度在PTC≤2。记录肌松药使用总量,肌松药使用时间(A组:诱导至泵注结束时间;B组:诱导到最后一次加药时间),手术时间,手术开始0、1、2h及关腹时肌松满意度(0~10分),恢复指数(T1从25%恢复至75%的时间),TOFr比值恢复至0.7、0.9的时间,以及压舌板试验完成情况,低氧血症、肺不张、肺炎等情况。结果与B组比较,A组平均肌松药使用量明显增加(P0.05);在手术开始0、1、2h时手术医师对肌松满意度A组明显高于B组(P0.05);恢复指数、TOFr比值恢复至0.7的时间和TOFr比值恢复至0.9的时间两组差异无统计学意义。拔管后A组出现低氧血症2例(7.1%),B组出现低氧血症1例(4.2%);不能完成压舌板试验A组3例(10.7%),B组4例(16.7%),两组差异均无统计学意义。术后均未出现肺不张、肺炎。结论持续输注顺式阿曲库铵用于腹腔镜手术维持深度肌松安全有效。相较于间断静注给药,持续输注肌松药使用量较大,肌松满意度高,虽然停药后恢复时间稍长,但对术后肌松残余无明显影响。     

性别因素对七氟醚增强顺阿曲库铵或罗库溴铵肌松效应的影响

目的 探讨性别因素对七氟醚增强顺阿曲库铵或罗库溴铵肌松效应的影响.方法 择期全麻手术患者240例,年龄20～60岁,ASA分级Ⅰ或Ⅱ级,BMI 20～30 kg/m2,随机分为2组(n=120):顺阿曲库铵组和罗库溴铵组,各组按性别和麻醉药再分4个亚组(n=30):女性异丙酚组、男性异丙酚组、女性七氟醚组和男性七氟醚组.各异丙酚组靶控输注异丙酚,血浆靶浓度2～6 μg/ml,各七氟醚组吸入七氟醚,于靶控输注或待呼气末七氟醚浓度稳定于1.71%5 min后,静脉注射顺阿曲库铵0.15 mg/kg或罗库溴铵0.6 mg/kg.记录肌松起效时间、肌松作用峰值时间、T1 25%恢复时间和TOFR25%恢复时间.结果 与异丙酚麻醉比较,女性患者七氟醚麻醉时,罗库溴铵TOFR 25%恢复时间延长,顺阿曲库铵肌松作用峰值时间、T1 25%恢复时间和TOFR 25%恢复时间延长,男性患者七氟醚麻醉时,罗库溴铵起效时间缩短,肌松作用峰值时间、T1 25%恢复时间和TOFR 25%恢复时间延长,顺阿曲库铵肌松作用峰值时间、T1 25%恢复时间和TOFR 25%恢复时间延长(P＜0.05或0.01);七氟醚麻醉时与男性患者比较,女性患者罗库溴铵T1 25%恢复时间和TOFR 25%恢复时间缩短,顺阿曲库铵起效时间缩短(P＜0.05或0.01).结论 七氟醚对罗库溴铵肌松的增强作用存在性别差异,男性强于女性;对顺阿曲库铵肌松的增强作用无明显性别差异.     

Recovery of neuromuscular block after continuous infusion of cisatracurium in patients with renal dysfunction]

OBJECTIVE: Study of the recovery of neuromuscular block after continuous infusion of cisatracurium in patients with renal dysfunction. STUDY DESIGN: Prospective case-control study. PATIENTS: Forty adult patients scheduled for urological surgery were assigned to two groups according to the creatinine clearance (CC) as a measure of the renal function: group IR (CC < 60 mL.min-1) or group NR (CC > or = 60 mL.min-1). METHODS: After premedication with hydroxyzine, anaesthesia was induced with propofol, sufentanil and cisatracurium (0.15 mg.kg-1), and maintained using isoflurane, sufentanil and a continuous infusion of cisatracurium (0.12 mg.kg-1.h-1) adjusted for maintained a post-tetanic count < or = 5. Neuromuscular transmission was monitored at the adductor pollicis using accelerography (TOF Gard). Onset and recovery times in both groups were compared using Student's t test. RESULTS: Infusion time and total dose of cisatracurium were comparable in both groups. Onset times were 3.9 +/- 0.8 min and 3.5 +/- 0.6 min in groups IR and NR respectively. After the infusion, the time to train-of-four ratio of 0.8 were not different in both groups: 77 +/- 18 min (group IR) and 73 +/- 13 min (group NR). However, the spontaneous recovery intervals 25%-75% were delayed in group IR (20 +/- 9 min vs 14 +/- 5 min p < 0.05). CONCLUSION: There are minor differences in the pharmacodynamics of cisatracurium between patients with normal or impaired renal function. Nevertheless, a marked interindividual variability in the recovery parameters was observed in patients with renal dysfunction.     

Primingtechnik mit Cisatracurium

OBJECTIVE: Priming can significantly shorten the onset of nondepolarizing neuromuscular blocking agents (NNBA) measured at the adductor pollicis muscle (APM). In spite of the known risks, priming is very popular especially in cases where NNBAs with a long onset time are used. However, there are no data regarding the onset of action for a priming technique measured at the laryngeal muscles although these muscles are of great importance for conditions of intubation and patient safety. The aim of this study was to compare a bolus application and a priming technique with respect to the laryngeal onset time and peak effect. PATIENT AND METHODS: After approval of the local ethics committee and written informed consent, 36 patients undergoing elective thyroid surgery were enrolled in the study. Anesthesia was induced and maintained with a target controlled infusion of propofol (target concentration 2.7-6.0 microg/ml) and infusion of remifentanil (0.25-0.75 microg/kgbw/min). After loss of consciousness, a tube with a surface electrode was placed into the trachea without the application of any neuromuscular blocking agent. Neuromuscular monitoring consisted of evoked electromyography (EMG) of the laryngeal adductor muscles via the surface electrode and evoked acceleromyography (TOF Guard) of the right adductor pollicis muscle (APM). After transcutaneous stimulation of the recurrent laryngeal nerve and ulnar nerve, either 0.9% NaCl followed by 0.1 mg/kgbw cisatracurium after 3 min (bolus group, n=12), a priming dose of 0.01 mg/kgbw cisatracurium followed by 0.09 mg/kgbw 3 min later (low dose priming group, n=12) or a priming dose of 0.015 mg/kgbw cisatracurium followed by cisatracurium 0.085 mg/kgbw 3 min later (high dose priming group, n=12) were injected. Lag time, onset time and peak effect of NMB were recorded and compared between the groups. RESULTS: Demographic data, lag time and peak effect were comparable between the three groups. Onset time at the laryngeal muscles was significantly shorter in the high dose priming group (80+/-17 s), when compared to the low dose priming group (128+/-23 s) and bolus group (142+/-29 s). Onset time at the APM was also significantly shorter in the high dose priming group (154+/-35 s), when compared with the bolus group (226+/-76 s). The recovery of the neuromuscular function measured at the APM showed no differences between the groups. CONCLUSION: Our results show that only high dose priming of cisatracurium can significantly shorten the laryngeal onset time. However, clinical routine use is not recommended due to possible side-effects.     

Effects of small doses of prostaglandin E(1) on systemic hemodynamics and jugular venous oxygen saturation during cardiopulmonary bypass

STUDY OBJECTIVE: To examine the effects of small doses of prostaglandin E(1) (PGE(1)) on systemic hemodynamics and cerebral oxygenation during cardiopulmonary bypass(CPB). DESIGN: Randomized, prospective study. SETTING: Cardiac surgery at Saitama Cardiovascular and Pulmonary Center. PATIENTS: Forty patients who underwent elective coronary artery bypass surgery. INTERVENTIONS: The study was performed at the stable CPB period. Patients were randomly divided into four groups: control group (n = 10) received an infusion of saline, PGE(1) 10 group (n = 10) received an infusion of PGE(1) 10 ng/kg/min, PGE(1) 25 group (n = 10) received an infusion of PGE(1) 25 ng/kg/min, and the PGE(1) 50 group (n = 10) received an infusion of PGE(1) 50 ng/kg/min. MEASUREMENTS: After measuring the baseline partial pressure of the arterial oxygen saturation (SpO(2)), mixed venous oxygen saturation (SvO(2)), and jugular venous oxygen saturation (SjvO(2)), blood gases, and cardiovascular hemodynamic values, PGE(1) was infused intravenously at rate of between 10 and 50 ng/kg/min. PGE(1) infusion continued 30 minutes after the start of drug infusion, and the blood gas analysis and cardiovascular hemodynamic values were simultaneously determined together with the hemodynamic values at 2, 5, 10, 20, and 30 minutes during drug infusion. At 30 minutes after discontinuation of the drug infusion, the blood gas analyses were simultaneously determined together with the hemodynamic values. MAIN RESULTS: Mean arterial pressure (MAP) in PGE(1) 25 and 50 groups was decreased 20 and 30 minutes after the start of PGE(1) infusion compared with the baseline value (p < 0.05). In contrast, SvOm(2) in PGE(1) 25 and 50 groups was increased 20 and 30 minutes after the start of PGE(1) infusion compared with the baseline value (p < 0.05). There was no change in SjO(2) value despite a decrease in MAP during the study. CONCLUSIONS: Cerebral oxygenation estimated by SjvO(2) was maintained despite a decrease in MAP during the administration rate of PGE(1) between 10 and 50 ng/kg/min.     

Correlation between cerebral and mixed venous oxygen saturation during moderate versus tepid hypothermic hemodiluted cardiopulmonary bypass

OBJECTIVE: This study was undertaken to compare cerebral oxygen saturation (RsO(2)) and mixed venous oxygen saturation (SvO(2)) in patients undergoing moderate and tepid hypothermic hemodiluted cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTINGS: University hospital operating room. PARTICIPANTS: Fourteen patients undergoing elective coronary artery bypass graft surgery using hypothermic hemodiluted CPB. INTERVENTIONS: During moderate (28 degrees -30 degrees C) and tepid hypothermic (33 degrees -34 degrees C) hemodiluted CPB, RsO(2) and SvO(2) were continuously monitored with a cerebral oximeter via a surface electrode placed on the patient's forehead and with the mixed venous oximeter integrated in the CPB machine, respectively. MEASUREMENTS AND MAIN RESULTS: Mean +/- standard deviation of RsO(2), SvO(2), PaCO(2), and hematocrit were determined prebypass and during moderate and tepid hypothermic phases of CPB while maintaining pump flow at 2.4 L/min/m(2) and mean arterial pressure in the 60- to 70-mmHg range. Compared with a prebypass value of 76.0% +/- 9.6%, RsO(2) was significantly decreased during moderate hypothermia to 58.9% +/- 6.4% and increased to 66.4% +/- 6.7% after slow rewarming to tepid hypothermia. In contrast, compared with a prebypass value of 78.6% +/- 3.3%, SvO(2) significantly increased to 84.9% +/- 3.6% during moderate hypothermia and decreased to 74.1% +/- 5.6% during tepid hypothermia. During moderate hypothermia, there was poor agreement between RsO(2) and SvO(2) with a gradient of 26%; however, during tepid hypothermia, there was a strong agreement between RsO(2) and SvO(2) with a gradient of 6%. The temperature-uncorrected PaCO(2) was maintained at the normocapnic level throughout the study, whereas the temperature-corrected PaCO(2) was significantly lower during the moderate hypothermic phase (26.8 +/- 3.1 mmHg) compared with the tepid hypothermic phase (38.9 +/- 3.7 mmHg) of CPB. There was a significant and positive correlation between RsO(2) and temperature-corrected PaCO(2) during hypothermia. CONCLUSIONS: During moderate hypothermic hemodiluted CPB, there was a significant increase of SvO(2) associated with a paradoxic decrease of RsO(2) that was attributed to the low temperature-corrected PaCO(2) values. During tepid CPB after slow rewarming, regional cerebral oxygen saturation was increased in association with an increase with the temperature-corrected PaCO(2) values. The results show that during hypothermic hemodiluted CPB using the alpha-stat strategy for carbon dioxide homeostasis, cerebral oxygen saturation is significantly higher during tepid than moderate hypothermia.     

Cisatracurium bei Koronarbypassoperationen – ein Vergleich mit Pancuronium Hämodynamische und neuromuskuläre Effekte bei Patienten unter chronischer β-Blockertherapie

OBJECTIVE: The aim of the study was to compare haemodynamic and neuromuscular effects of cisatracurium and pancuronium in patients undergoing coronary artery bypass grafting (ASA III, good or moderately impaired LV function) who were chronically medicated with beta-adrenergic blocking agents. METHODS: 60 Patients were randomly assigned in a double-blind fashion to receive sufentanil/midazolam/etomidate and either pancuronium (2xED95, group P) or cisatracurium (2xED95, group C2 and 4xED95, group C4). Haemodynamic variables were measured using arterial and pulmonary arterial catheters, neuromuscular transmission was measured using electromyography. RESULTS: The heart rate was significantly lower in group C2 (50.2 +/- 6.8 bpm) and in group C4 (54.3 +/- 11 bpm) than in the pancuronium group (62.4 +/- 13.2 bpm) 3 min after induction of anaesthesia and until 60 min after induction. None of the other haemodynamic parameters showed any difference between groups. Onset time was 5.22 +/- 3.43 min in group P, 6.42 +/- 2.1 min in group C2 and 2.92 +/- 1.2 min in group C4. CONCLUSION: Under high-dose opioid induction, bradycardia must be considered if cisatracurium is administered to cardiac surgery patients.     

Pharmacodynamic interactions between cisatracurium and rocuronium

The onset and duration of maintenance doses of neuromuscular blocking drugs may be influenced by the original neuromuscular blocking drug used. We assessed the effect of the interaction between steroidal and benzo-isoquinolinium compounds on the clinical duration of maintenance doses of cisatracurium. Sixty adult patients undergoing anesthesia with isoflurane, nitrous oxide, and oxygen were randomized to receive the following: Group I = rocuronium 0.6 mg/kg followed by cisatracurium 0.03 mg/kg when the first twitch in the train-of-four (TOF) recovered to 25%, Group II = cisatracurium 0.15 mg/kg followed by cisatracurium 0.03 mg/kg, and Group III = rocuronium 0.6 mg/kg followed by rocuronium 0.15 mg/kg. Neuromuscular blockade was monitored using acceleromyography (TOF-Guard, Boxtel, The Netherlands). The clinical duration (mean +/- SD) of the first 2 maintenance doses was 41 +/- 10, 31 +/- 7++, and 25 +/- 8++ min, and 39 +/- 11, 30 +/- 6+, 29 +/- 9* min in Groups I-III, respectively (*P < 0.05, +P < 0.01, ++P < 0.001; Group I versus II and III). Thus, the clinical duration of the first two maintenance doses of cisatracurium was prolonged when administered after rocuronium. IMPLICATIONS: We assessed the clinical effect of administering cisatracurium after an intubating dose of rocuronium in 60 patients undergoing isoflurane/nitrous oxide and oxygen anesthesia. The clinical duration of the first two maintenance doses of cisatracurium administered after rocuronium was significantly prolonged. This supports the contention that combinations of structurally dissimilar neuromuscular blocking drugs result in a synergistic effect.     

Monitorage de la Sv̄2 en chirurgie aortique: intérêt et limites

This study aimed to determine perioperative changes in mixed venous oxygen saturation (SvO2) in patients undergoing aortic surgery. Continuous SvO2 monitoring was carried out using an Oximetrix pulmonary catheter. Fourteen patients were randomly assigned to 2 groups, group I (n = 7) patients being given a thoracic epidural anaesthetic with a supplementary general anaesthetic, and group II (n = 7) a general anaesthetic as usual. In both groups, SvO2 increased at induction. In group I patients, SvO2 decreased during surgery to less than 60% (n = 2) and less than 70% (n = 4). This fall was corrected by volume loading and intravenous ephedrine. The intraoperative decrease in SvO2 occuring in 2 group II patients was due to a fall in haematocrit in one, and a propranolol infusion in the other. Although patients in group I were all extubated early after the end of surgery (85 +/- 35 min), the lowest value of SvO2 after extubation was always greater than 60%. Patients undergoing aortic surgery under thoracic epidural anaesthesia can be extubated early, without markedly depressing peripheral reserves in oxygen extraction.     

A double-blind, randomized comparison of low-dose rocuronium and atracurium in a desflurane anesthetic

STUDY OBJECTIVES: To compare the neuromuscular and hemodynamic effects of rocuronium and atracurium when administered during a desflurane-based anesthetic. DESIGN: Randomized, double-blind clinical trial. PATIENTS: 51 adult ASA physical status I and II patients scheduled for general surgical operations. SETTING: University-based NCI-designated cancer center. INTERVENTIONS: Patients received either 0.45 mg/kg rocuronium (n = 28) or atracurium 0.5 mg/kg (n = 23). Induction of anesthesia was accomplished by 2 microg/kg fentanyl intravenously (IV) and 1.5 mg/kg propofol IV and maintained by a nitrous oxide/oxygen desflurane anesthetic. MEASUREMENTS AND MAIN RESULTS: A neuromuscular monitor was used at the adductor pollicis to monitor and record twitch response to train-of-four electrical stimulation. Baseline heart rate (HR) and blood pressure (BP) were measured and again at 2, 5, 10, and 15 minutes after muscle relaxant administration. Patients in the rocuronium group were found to have shorter times to 80%T(1)depression (109 +/- 53 vs. 135 +/- 47 sec), although those differences did not reach statistical significance (p = 0.07). Percent of the first twitch (T(1) ) was significantly lower in the patients receiving rocuronium at 60 seconds (53 +/- 24 vs. 73 +/- 27 sec; p = 0.006) and 90 seconds (25 +/- 22 vs. 47 +/- 29 sec; p = 0.003) than in the patients receiving atracurium. Duration was shorter in rocuronium-treated patients (25% T(1) recovery = 32 +/- 12 vs. 54 +/- 14 min; p < 0.001) than the patients receiving atracurium. Intubation scores were better at 60 seconds after muscle relaxant administration in the rocuronium group. No significant differences in HR or BP were seen between the patients in the two groups. CONCLUSIONS: Rocuronium at a dose of 0.45 mg/kg possesses a fairly rapid onset of neuromuscular blockade and has short:intermediate duration of action when used with a desflurane anesthetic. This quality makes it a desirable drug for operations of relatively short duration. Rocuronium at a dose of 0.45 mg/kg has a faster onset and shorter duration than atracurium, at 0.5 mg/kg, when used with a desflurane anesthetic.     

不同麻醉下脊柱侧弯矫形术患者术中唤醒试验的比较

目的 比较不同麻醉下脊柱侧弯矫形术患者术中唤醒试验.方法 选择拟行脊柱侧弯矫形术患者40例,年龄13～ 18岁,性别不限,BMI＜ 30 kg/m2,ASA分级Ⅰ级.采用随机数字表法,将患者随机分为2组(n=20):异丙酚复合舒芬太尼组(P组)和靶控吸入七氟醚复合舒芬太尼组(S组).麻醉维持时S组靶控吸入七氟醚,呼气末靶浓度0.8％～1.5％;P组靶控输注异丙酚,血浆靶浓度3～5μg/rml,两组均靶控输注舒芬太尼,效应室靶浓度0.2 ～ 0.3 ng/ml.唤醒试验前停止输注顺阿曲库铵,下调舒芬太尼效应室靶浓度至0.1.ml;5 min后,S组停用七氟醚,P组停用异丙酚;5 min后开始唤醒试验.于唤醒试验前、唤醒成功时及唤醒成功后10 min(T0～2)时记录MAP和HR,记录唤醒时间、唤醒期间呛咳、躁动的发生情况,术后随访记录患者术中知晓的发生情况.结果 与P组比较,S组术中唤醒时间短(P＜0.05).两组术中唤醒期间MAP和HR均在正常范围内,两组比较差异无统计学意义(P＞0.05).所有患者术中唤醒试验均成功,术中唤醒期间无一例发生呛咳、躁动及术中知晓.结论 靶控吸入七氟醚复合舒芬太尼可安全有效地用于脊柱侧弯矫形术患者术中唤醒试验,且唤醒时间短于靶控输注异丙酚复合舒芬太尼麻醉,更适用于术中唤醒试验.     

The effects of prostaglandin E1 on systemic and cerebral oxygenation before and during cardiopulmonary bypass

The purpose of this study was to examine the effects of a small dose of prostaglandin E1 on systemic and cerebral oxygenation. Thirty patients for coronary artery bypass graft surgery were randomly divided into two groups: Group 1 received PGE1 25 ng.kg-1.min-1. Group 2 received PGE1 50 ng.kg-1.min-1. After measuring baseline hemodynamics and mixed (SvO2) and juglar (SjvO2) venous oxygen saturations, administration of PGE1 at a rate of 25 ng.kg-1.min-1 or 50 ng.kg-1.min-1 was started before and during CPB. In group 2, mean arterial pressure (MAP) decreased during CPB, while in group 1, MAP was unchanged during CPB. There was no change in SjvO2 both in group 1 and group 2 before and during CPB. The administration of PGE1 at a rate of 25 ng.kg-1.min-1 during CPB was suitable for the maintenance of SvO2 and SjvO2.