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.     

顺式阿曲库铵不同用药方式对老年全凭静脉麻醉肌松作用的影响

目的 探讨顺式阿曲库铵不同用药方式对老年患者全凭静脉麻醉肌松作用的影响.方法 60例掸期在全麻下行普外科手术的老年患者,ASA I～Ⅱ级.年龄7l～87岁,随机分为A组(η=20)和B组(η=40),其中B组再随机分为B1组(η=20)和B2组(η=20).肌松诱导:A组单次予顺式阿曲库铵0.2 mg·kg-1静注;B...     

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.     

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.     

Epidural ropivacaine or sufentanil-ropivacaine infusions for post-thoracotomy pain.

OBJECTIVE: The aim of this study was to compare the analgesic efficacy and side effects of continuous epidural infusions of ropivacaine and ropivacaine-sufentanil mixtures after thoracotomy. METHODS: Sixty-two patients scheduled for thoracic surgery were allocated in this prospective double-blinded randomised study. They received an epidural catheter inserted from thoracic 5-6 (Th(5-6)) interspace a day before surgery and were randomly assigned into two groups, sufentanil-ropivacaine group (Group SR, n=31) and ropivacaine group (Group R, n=31). Bolus dose of the study drugs, ropivacaine 0.2% or ropivacaine 0.2% and sufentanil 0.75 microg/ml calculated in ml according to the patient's height was given through the epidural catheter before surgery. One hour after anaesthesia induction, another bolus was given and the epidural infusion was started (4.5-8 ml). Whenever visual analogue scale (VAS) scores were > or =4 during function, the patients received additional boluses and the infusion rate was increased by 1 ml/h. If the pain was not relieved after administration of two boluses, the patient was excluded from the study. RESULTS: VAS at rest and during function was lower in ropivacaine-sufentanil group and the need for additional boluses and infusion rate increase was high in ropivacaine group (P<0.05). Ropivacaine-sufentanil infusion rate was decreased due to nausea and vomiting in two patients and due to CO(2) retention in one patient. There was no statistically significant difference between the incidences of side effects except pruritus significantly higher in Group SR. The total epidural solution volume was more in Group R (P<0.05). CONCLUSIONS: The continuous epidural infusion of ropivacaine with sufentanil provided superior pain relief than ropivacaine alone without causing any severe side effect or post-operative pulmonary impairment.     

Effect of an intravenous infusion of lidocaine on cisatracurium‐induced neuromuscular block duration: a randomized‐controlled trial

Background: Intravenous lidocaine can be used intraoperatively for its analgesic and antihyperalgesic properties but local anaesthetics may also prolong the duration of action of neuromuscular blocking agents. We hypothesized that intravenous lidocaine would prolong the time to recovery of neuromuscular function after cisatracurium. Methods: Forty‐two patients were enrolled in this randomized, double‐blind, placebo‐controlled study. Before induction, patients were administered either a 1.5 mg/kg bolus of intravenous lidocaine followed by a 2 mg/kg/h infusion or an equal volume of saline. Anaesthesia was induced and maintained using propofol and remifentanil infusions. After loss of consciousness, a 0.15 mg/kg bolus of cisatracurium was administered. No additional cisatracurium injection was allowed. Neuromuscular function was assessed every 20 s using kinemyography. The primary endpoint was the time to spontaneous recovery of a train‐of‐four (TOF) ratio ≥0.9. Results: The time to spontaneous recovery of a TOF ratio ≥0.9 was 94 ± 15 min in the control group and 98 ± 16 min in the lidocaine group (P=0.27). Conclusions: No significant prolongation of spontaneous recovery of a TOF ratio ≥0.9 after cisatracurium was found in patients receiving intravenous lidocaine.     

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.     

Assessment of residual curarization using low-current stimulation

The present study employed train-of-four (TOF) stimulation at a current of 20 mA to assess the incidence and degree of residual neuromuscular blockade in 64 randomly selected Post Anesthesia Care Unit (PACU) patients. Group C (Control, n = 10) had received anaesthesia without nondepolarizing muscle relaxant; Group V (n = 25) had received vecuronium; and Group P (n = 29) had received pancuronium. At the end of surgery, each patient had been considered by his anaesthetist to have adequate neuromuscular function on the basis of clinical signs and tactile or visual evaluation of responses to TOF stimulation. However, upon testing in the PACU 15 min later, 45% (13 of 29) of Group P patients and 8% (2 of 25) of Group V patients had a TOF ration less than 0.70. This study indicates that residual curarization may be commonly encountered following long-acting relaxants despite qualitative intraoperative TOF monitoring. The present incidence, detected at a current of 20 mA, is consistent with previous reports which employed supramaximal TOF stimulation. We conclude that despite intraoperative monitoring, residual curarization following long-acting nondepolarizing agents is common and that it may be detected with TOF at a low stimulating current (20 mA).     

Muscle relaxation does not influence venous oxygen saturation during cardiopulmonary bypass

STUDY OBJECTIVE: To examine whether the omission of neuromuscular blocking drugs during cardiopulmonary bypass (CPB) is associated with increased anesthetic requirements, higher frequency of intraoperative movements, and lower venous oxygen saturation (SvO(2)). DESIGN: Prospective, randomized study. SETTING: Large community hospital. PATIENTS: 30 ASA physical status III and IV patients scheduled for cardiac surgery. INTERVENTIONS: Patients were randomized to one of two groups: group 1 (n = 15) received a 3xED(95) bolus dose of cisatracurium at induction and thereafter no more neuromuscular blocking drug; group 2 (n = 15) received a continuous infusion of cisatracurium during the entire procedure. INTERVENTIONS: Both groups received a standardized anesthetic with bispectral index-guided propofol target-controlled infusion and a remifentanil infusion steered by hemodynamic changes. Venous oxygen saturation was continuously determined during CPB. MEASUREMENTS AND MAIN RESULTS: Propofol consumption was 5.4 +/- 1.7 and 4.4 +/- 1.0 mg/(kg/h) in groups 1 and 2, respectively (P = 0.07). Remifentanil consumption was 0.15 +/- 0.05 and 0.17 +/- 0.05 mug/(kg/min) in groups 1 and 2, respectively (P = 0.19). In groups 1 and 2, no patient recalled any intraoperative phenomena; none moved or had diaphragmatic contractions. During CPB, SvO(2) was 81.3 +/- 3.2% (76%-85%) in group 1 and 80.6 +/- 3.1% (73%-85%) in group 2 (P = 0.53). CONCLUSIONS: Omitting the continuous administration of neuromuscular blocking drugs during CPB did not increase anesthetic requirements. No intraoperative movements occurred, nor was there decreased SvO(2).     

Infusion and bolus administration of cisatracurium--effects on histamine release

The purpose of this study is to evaluate the usefulness of Cisatracurium Besilat (CB), and the method of its administration during laparotomies on adult patients, to determine whether CB caused cutaneous, systemic or chemical evidence of histamine release. This study was conducted as a randomized, double-blind clinical trial on 38 patients (ASA I-II). After a standard anesthetic induction with fentanyl and propofol, patients received an i.v. bolus CB (0.15 mg/kg in Group A (n=20) or Group B (n=18). In Group B, 0.18 mg/kg/h infusion was started. Following reaching stable muscle relaxations for intraabdominal operation and for recovery, Group A (Bolus group) and Group B (Infusion group) were compared. Train-of-four fade during recovery of block were recorded after administration of CB. The heart rate and arterial blood pressure were monitored noninvasively. There were no significant hemodynamic differences among the groups. 25%-75% spontaneous recoveries were (mean+/-s) 12.75+/-4.52, 16.11+/-9.20 minutes for Group A, Group B. 70% TOF Ratios were (mean+/-s) 1.07+/-0.13, 1.39+/-0.38 hours for the same groups. There was no consistent correlation between hemodynamic changes, cutaneous manifestations and histamine concentrations. We conclude that CB does not cause systemic or cutaneous histamine release. The infusion method of cisatracurium has a stable level of curarization without side effect and there were no significant recovery time differences between the groups.     

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.     

Accelerated reversal of atracurium blockade with divided doses of neostigmine

The hypothesis that administration of neostigmine in divided doses might accelerate the antagonism of neuromuscular blockade was investigated. Neostigmine 0.05 mg X kg-1 was administered either in a single bolus dose (Group I, n = 16) or in an initial dose of 0.01 mg X kg-1 followed three minutes later by 0.04 mg X kg-1 (Group II, n = 16) for antagonism of atracurium-induced blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. The mean time (+/- SD) from the first injection of the drug until the train-of-four (TOF) ratio value had reached 0.75 was significantly shorter in Group II (p less than 0.05) than in Group I (391.8 +/- 83.3 and 468.6 +/- 150.3 seconds respectively). The rate of TOF ratio recovery was 2.5 times faster after neostigmine administration in divided doses. It is concluded that administration of neostigmine in divided doses, as described in this study, produced a significantly faster reversal of residual atracurium-induced neuromuscular blockade as compared to a single bolus administration.     

Recovery from neuromuscular blockade after either bolus and prolonged infusions of cisatracurium or rocuronium using either isoflurane or propofol-based anesthetics

We examined the recovery characteristics of cisatracurium or rocuronium after bolus or prolonged infusion under either isoflurane or propofol anesthesia. Sixty patients undergoing neurosurgical procedures of at least 5 h were randomized to receive either isoflurane with fentanyl (Groups 1 and 2) or propofol and fentanyl (Groups 3 and 4) as their anesthetic. Groups 1 and 3 received cisatracurium 0.2 mg/kg IV bolus, spontaneously recovered, after which time an infusion was begun. Groups 2 and 4 received rocuronium 0.6 mg/kg IV, spontaneously recovered, and an infusion was begun. Before the end of surgery, the infusion was stopped and recovery of first twitch (T(1)), recovery index, clinical duration, and train-of-four (TOF) recovery was recorded and compared among groups by using appropriate statistical methods. Clinical duration was shorter for rocuronium compared with cisatracurium using either anesthetic. Cisatracurium T(1) 75% recovery after the infusion was shorter with propofol compared with isoflurane. Cisatracurium TOF 75% recovery was similar after either bolus or infusion, but rocuronium TOF 75% recovery after the infusion was delayed. Infusion rates decreased for cisatracurium but remained relatively constant for rocuronium regardless of the anesthetic used. Isoflurane enhances the effect of both muscle relaxants but prolonged cisatracurium recovery more than rocuronium. Of the two muscle relaxants studied, rocuronium's recovery was most affected by length of the infusion. Cisatracurium may be a more desired muscle relaxant for prolonged procedures because recovery was least affected by prolonged infusion. Implications: This study describes the effect of different anesthetic techniques on the recovery of two different muscle relaxants, cisatracurium and rocuronium, when administered as either a single bolus or prolonged infusion during neurosurgery. This study demonstrates the feasibility of using these relaxants for these prolonged procedures.     

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。     

Antagonism of profound cisatracurium and rocuronium block: the role of objective assessment of neuromuscular function

STUDY OBJECTIVE: The purpose of this study is to determine the incidence of significant (train-of-four [TOF] ratio <0.70), but clinically undetectable (TOF ratio >0.40), residual neuromuscular block after neostigmine antagonism of profound cisatracurium (CIS) or rocuronium (ROC) block. DESIGN: Prospective, randomized, open-label study. SETTING: University hospital. PATIENTS: Forty ASA physical status I and II undergoing elective surgical procedures. INTERVENTIONS: Anesthesia was induced with propofol 1.5 to 2.5 mg/kg IV plus fentanyl 2 to 4 mug/kg and maintained with N(2)O/desflurane plus narcotic supplementation. The electromyographic response of the adductor pollicis was recorded. Train-of-four stimulation was given every 20 seconds. Twitch height (T1) and TOF fade ratio were continuously recorded. In group 1 (n = 20), neuromuscular block was induced with CIS 0.10 mg/kg, and T1 was maintained at 5% of control by a constant infusion of CIS until the end of surgery. One minute after the termination of the infusion, neostigmine 0.05 mg/kg was administered. T1 and TOF values were monitored continuously for the next 20 minutes. Group 2 (n = 20) is identical to group 1 except that the initial drug was ROC 0.60 mg/kg, and paralysis was maintained with an infusion of ROC. MEASUREMENTS AND MAIN RESULTS: There were no significant differences in the recovery patterns of CIS vs ROC. The duration (bolus to end of infusion) in both groups averaged 2.7 hours, and the mean cumulative dose of relaxant approximated 4 x the ED(95). T1 at the time of reversal was 6% (4%-10%) of control. Mean TOF ratios at 10, 15, and 20 minutes were 0.55, 0.71, and 0.0.81, respectively. Return to a TOF ratio >0.40 was always achieved in 15 minutes or less. However, at 20 minutes postreversal, 5 of 40 subjects had TOF ratios <0.70 and only 11 individuals had recovered to a TOF ratio of 0.90 or greater. CONCLUSIONS: Most clinicians cannot detect tactile fade once the TOF ratio exceeds 0.40. When reversing profound block, an objective monitor of neuromuscular function is required if the extent of residual block is to be assessed with any confidence.     

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.     

Remifentanil administration during monitored anesthesia care: are intermittent boluses an effective alternative to a continuous infusion?

This randomized, double-blind study was designed to evaluate the analgesic effectiveness and respiratory stability of remifentanil when administered as intermittent bolus injections, a variable-rate infusion, or a combination of a constant basal infusion supplemented with intermittent boluses during monitored anesthesia care (MAC). Forty-five patients undergoing extracorporeal shock wave lithotripsy (ESWL) procedures were randomly assigned to one of the three modes of remifentanil administration. All patients received midazolam 2 mg i.v., followed by a propofol infusion at 50 microg x kg(-1) x min(-1). Two minutes before administering a series of test shock waves: Group I received a remifentanil infusion of 0.1 microg x kg(-1) x min(-1), and a saline bolus (5 mL); Group II received a saline infusion and a remifentanil bolus (25 microg in 5 mL); and Group III received a remifentanil infusion of 0.05 microg x kg(-1) x min(-1), and a remifentanil bolus (12.5 microg in 5 mL). The average pain intensity was scored on an 11-point scale, with 0 = no pain to 10 = severe pain. During the ESWL procedure, pain was treated by increasing the study drug infusion rate by 25%-50% and administering 5-mL bolus injections of the study medication in Groups I (saline) and II (remifentanil 25 microg). In Group III, intermittent 5-mL boluses (remifentanil 12.5 microg) were administered as needed. Patients in Groups II and III reported lower pain scores in response to the test shocks. Significantly more remifentanil was administered in Group I (379 +/- 207 microg) than in Group II (201 +/- 136 microg). However, more interventions were required for the treatment of intraoperative pain in the intermittent bolus group (Group II). When remifentanil is administered as the analgesic component of a MAC technique, these data support the use of intermittent bolus doses (12.5-25 microg) alone or in combination with a basal infusion (0.05 microg x kg(-1) x min(-1)) as alternatives to a variable-rate continuous infusion. IMPLICATIONS: In this study, three different modes of remifentanil administration were used during monitored anesthesia care for extracorporeal shock wave lithotripsy procedures. These results suggest that using intermittent bolus injections of remifentanil (25 microg) or a continuous infusion (0.05 microg x kg(-1) x min(-1)) supplemented with intermittent bolus (12.5 microg) injections may be more effective than a variable-rate infusion of remifentanil during propofol sedation.     

Haemodynamic effects of ketanserin following coronary artery bypass grafting.

The haemodynamic effects of ketanserin were studied consecutively in seventeen patients in the intensive care unit following coronary artery bypass grafting. Hypertensive patients (Group 1, systolic blood pressure (SBP) greater than or equal to 150 mmHg following discontinuation of nitroprusside, n = 10) received intravenous ketanserin 10 mg and infusion of 0.1 mg.kg-1.hr-1 with additional boluses as required to maintain SBP less than or equal to 130 mmHg for one hour. Non-hypertensive patients (Group 2, SBP less than 150 mmHg, n = 7) received a 5 mg bolus and the same infusion. Ketanserin significantly decreased arterial blood pressure (P less than 0.001) in all patients in Group 1. Heart rate was decreased but not significantly. Cardiac index, systemic and pulmonary vascular resistance and pulmonary shunt fraction were not significantly altered from pre-ketanserin values when blood pressure was controlled with nitroprusside. Normotensive patients in Group 2 did not show any undesirable hypotension or significant haemodynamic changes. Mean nitroprusside dose requirements following ketanserin therapy were significantly reduced by 91.6% in Group 1 and 78.4% in Group 2 (P less than 0.05). Ketanserin is effective in treating hypertension following coronary artery bypass grafting with an advantage of lack of reflex tachycardia.     

Die Wirkung unterschiedlicher Primingdosierungen auf die Pharmakodynamik von Cisatracurium

OBJECTIVE: The aim of the study was to evaluate the effect of two different priming regimen on the onset time of 100 micrograms/kg cisatracurium, when compared to bolus administration. METHODS: 51 patients were randomly assigned and received either a bolus of 100 micrograms/kg cisatracurium, or a priming dose of 10 micrograms/kg cisatracurium followed after 4 min by 90 micrograms/kg cisatracurium, or a priming dose of 15 micrograms/kg cisatracurium followed after 4 min by 85 micrograms/kg cisatracurium. The neuromuscular monitoring was performed using a mechanomyograph (Groningen II Monitor). Anaesthesia was induced with propofol and fentanyl and maintained by continuous infusion of propofol. RESULTS: The priming combination of 15 micrograms/kg cisatracurium followed after 4 min by 85 micrograms/kg cisatracurium produced a statistically significant reduction in the onset time (95% block) (180 +/- 60 s) and time to complete block (210 +/- 48 s), when compared to the bolus group (240 +/- 60 s and 288 +/- 66 s) (p < 0.05). CONCLUSION: Our data indicate that the "priming principle" is an appropriate technique to shorten the onset time of cisatracurium. To achieve a maximum effect the priming combination of 15 micrograms/kg cisatracurium followed after 4 min by 85 micrograms/kg cisatracurium is recommended.