Neostigmine after spontaneous recovery from neuromuscular blockade

The effect of neostigmine on neuromuscular function was examined after spontaneous recovery from an atracurium-induced neuromuscular blockade, which reached a train-of-four ratio of either 0.5 or 0.9. Two doses of neostigmine 2.5 mg were given 5 minutes apart. Neuromuscular recovery was assessed with train-of-four and tetanic stimuli. The first dose of neostigmine antagonised the neuromuscular blockade. The second dose diminished tetanic height and increased tetanic fade. The train-of-four measured mechanically was adversely affected to a small degree, but when measured with the electromyograph no significant change occurred. Neostigmine may adversely affect neuromuscular function after spontaneous recovery from a non-depolarising block. This is unlikely with a single modest dose and any effects are probably short-lived.     

Recovery of neuromuscular function after cardiac surgery: pancuronium versus rocuronium

The use of pancuronium in fast-track cardiac surgical patients may be associated with delays in clinical recovery. Our objective in this study was to evaluate the incidence and severity of residual neuromuscular blockade after cardiac surgery in patients randomized to receive either pancuronium (0.08-0.1 mg/kg) or rocuronium (0.6-0.8 mg/kg). Eighty-two patients undergoing cardiopulmonary bypass were randomized to a pancuronium (n = 41) or rocuronium (n = 41) group. Intraoperative and postoperative management was standardized. In the intensive care unit, train-of-four (TOF) ratios were measured each hour until weaning off ventilatory support was initiated. Neuromuscular blockade was not reversed. After tracheal extubation, patients were examined for signs and symptoms of residual paresis. When weaning of ventilatory support was initiated, significant neuromuscular blockade was present in the pancuronium subjects (TOF ratio: median, 0.14; range, 0.00-1.11) compared with the rocuronium subjects (TOF ratio: median, 0.99; range, 0.87-1.21) (P < 0.05). Patients in the rocuronium group were more likely to be free of signs and symptoms of residual paresis than patients in the pancuronium group. Our findings suggest that the use of longer-acting muscle relaxants in cardiac surgical patients is associated not only with impaired neuromuscular recovery, but also with signs and symptoms of residual muscle weakness in the early postoperative period. IMPLICATIONS: The use of long-acting muscle relaxants in fast-track cardiac surgical patients is associated with significant residual neuromuscular block in the intensive care unit, including signs and symptoms of residual paresis.     

Onset and recovery of neuromuscular blockade after two doses of rocuronium in children

Study Objective: To determine if 450 μg/kg (1.5 times the ED₉₅) of rocuronium would result in a comparable onset with a shorter duration of action when compared with 600 μg/kg (2 times the ED₉₅).

Design: Randomized, single-blind study.

Setting: Teaching hospital.

Patients: 85 ASA physical status I and II children ages 2 through 12, undergoing elective surgery with an inhalation induction using halothane.

Interventions: Group 1 received 600 μg/kg rocuronium, and Group 2 received 450 μg/kg rocuronium.

Measurements and Main Results: The two groups were compared using a Student’s t-test, with p < 0.05 significant. The time of onset, or time to 95% suppression of neuromuscular twitch with standard errors, was 140 ± 13 seconds (range 46 to 365 sec) in Group 1 and 148 ± 13 seconds (range 82 to 345 sec) in Group 2 (NS = not significant). The times to 25% return of twitch from baseline (T₂₅) in Groups 1 and 2 were 28 ± 1.5 minutes (range 14 to 45 min) and 26 ± 1.6 minutes (range 10 to 55 min), respectively (NS). The differences between these two doses in onset of, and recovery from, block were not found to be statistically significant. The results, however, excluded 5% of the higher dose group and 31% of the lower dose group who did not achieve 95% suppression of twitch. Time to maximal suppression of neuromuscular blockade, however, was not statistically significant for the 85 patients with a time of 270 ± 28 seconds (range 91 to 605 sec) with a mean maximal suppression of 98.7% in Group 1 and 313 ± 25 seconds (range 91 to 899 sec) with a mean maximal suppression of 93.1% in Group 2.

Conclusion: The two doses of rocuronium did not differ statistically in onset or duration. Rocuronium at 600 μg/kg offers more reliability than 450 μg/kg in achieving adequate muscle relaxation, and the lower dose may result in a significantly large number of patients who may have inadequate intubating conditions.     

Lidocaine accelerates recovery of brain electrical activity after 3 minutes of complete ischemia in the rabbit

We recently reported that the continuous infusion of a low dose of lidocaine accelerated the recovery of the electroencephalogram and somatosensory evoked potentials after 20 min of incomplete cerebral ischemia in a single carotid artery preparation in the rabbit. In contrast, the recovery of the electroencephalogram and the auditory evoked potentials was minor on a comparable animal preparation subjected to 5 min of almost complete global ischemia. In the present study, we tested the hypothesis that the facilitatory effect of lidocaine on neuroelectrical recovery is of importance only during a certain combination of duration and severity of an ischemic episode. Similar to the previous studies, the rabbits had one carotid and both vertebral arteries permanently occluded and the other carotid artery reversibly clamped during the ischemic test. In the halothane-anesthetized animals, we monitored mean arterial pressure, carotid stump pressure, cerebral blood flow, auditory evoked potentials, and the electroencephalogram, before and for 90 min after 3 min of complete ischemia. The amplitude of the P1 wave (latency of 10 ms) of the auditory evoked potentials recovered more rapidly than on the previous 5 min preparation and returned towards the control amplitude more completely (p <0.05) in the lidocaine group. More importantly, the amplitude of the P2 wave (latency of 25 ms) recovered only 11% in the control group and 55% (p <0.05) in the lidocaine-infused animals. Comparable effects were observed in the early recovery of electroencephalographic activity during reperfusion. The present findings support the hypothesis that lidocaine may facilitate the recovery of the electroencephalogram and the evoked potentials only when an ischemic episode is below a certain combined level of duration and severity. The accelerating effect of lidocaine on postischemic neuroelectrical recovery was observed using a low dose of the drug, and it was not associated with changes in hemodynamic or cerebrovascular parameters or of blood composition. The latter suggests that the reported action may be related to some specific property of the local anesthetic action of lidocaine, such as blockade of axonal Na channels.     

Predicting recovery from deep neuromuscular block by rocuronium in the elderly

STUDY OBJECTIVE:To determine the influence of aging on the relationship between posttetanic count (PTC) and train-of-four (TOF) response during intense neuromuscular blockade caused by rocuronium. DESIGN: Prospective, observational, clinical comparison study. SETTING: Operating room of a university hospital. PATIENTS: 42 ASA physical status I and II patients, 20 of whom were elderly (ages 65 to 80 yrs) and 22 younger control patients (ages 18 to 40 yrs), who were scheduled for elective orthopedic surgery and ear, nose, and throat surgery with a planned duration of 2 hours. INTERVENTIONS: Neuromuscular blockade was evaluated with accelerometry of the thumb, using posttetanic twitch (PTT) and TOF stimulation of the ulnar nerve, in patients who received rocuronium 1 mg x kg(-1). MEASUREMENTS AND MAIN RESULTS: The first responses to posttetanic nerve stimulation were seen at mean times of 38.5 and 35.2 minutes after the injection of rocuronium in the elderly and in the young, respectively (NS). The average interval between the appearance of a posttetanic response and the first response to TOF stimulation (T1) was longer in the elderly than the young (22.3 +/- 8.1 (SD) vs.14.8 +/- 4.2 min, p < 0.05). There was a significant correlation between PTC and the time to first response to TOF nerve stimulation both in the elderly and in the young (r = -0.73, p < 0.0001 and r = -0.87, p < 0.0001, respectively). CONCLUSIONS: Posttetanic twitch stimulation is a useful method of monitoring intense neuromuscular blockade caused by rocuronium in both age groups. The interval between the earliest appearance of a posttetanic response and the first response to TOF stimulation (T1) is greater in the elderly than in the young.     

Nicorandil accelerates recovery of neuromuscular block caused by vecuronium

PURPOSE: To examine the effect of nicorandil, a K ATP channel agonist, on neuromuscular block caused by vecuronium in patients anesthetized with nitrous oxide, oxygen, isoflurane, and fentanyl. METHODS: Sixty adult patients were allocated to four groups of 15: nicorandil-post-tetanic count (N-PTC), nicorandil-train-of-four (N-TOF), control-post-tetanic count (C-PTC) or control-train-of-four (C-TOF) group. In the N-PTC and N-TOF groups, 0.1 mg kg nicorandil was given as a bolus followed by an infusion at 1 microg x kg(-1) x min(-1). Two minutes after the bolus, 0.1 mg x kg(-1) vecuronium was administered. In the C-PTC or C-TOF group normal saline was given instead of nicorandil. PTC and TOF responses were measured mechanically using a force displacement transducer. RESULTS: Time from the administration of vecuronium to the onset of neuromuscular block in the N-PTC or N-TOF group did not differ from that in the C-PTC or C-TOF group (241 +/- 33 vs 225 +/- 32 sec, mean +/- SD). Times from vecuronium injection to the return of PTC in the N-PTC and C-PTC groups, and those of T1, T2, T3, and T4 (first, second, third, and fourth stimulation of TOF) in the N-TOF and C-TOF groups did not differ. Recoveries of PTC in the N-PTC and C-PTC groups followed similar time course. T1/control twitch height and TOF ratio (T4/T1) in the N-TOF group were higher than those in the C-TOF group 80-120 min and 100-120 min after administration of vecuronium, respectively. CONCLUSION: Nicorandil accelerates recovery of neuromuscular block caused by vecuronium.     

Possible augmentation of neuromuscular blockade by propofol during recovery from rocuronium

Propofol is a widely used drug in anesthesia practice, and its pharmacological characteristics are well known. However, propofol is not known for neuromuscular effects. As part of clinical neuromuscular monitoring, the neuromuscular responses to train-of-four (TOF) stimulation were monitored and recorded. We observed, in two cases of balanced anesthesia maintained by desflurane and fentanyl, that administration of a small dose of propofol during almost complete recovery from rocuronium in two patients resulted in marked decreases of both T1 (first twitch response of the TOF) and the TOF ratio. This neuromuscular block dissipated in both patients without any subsequent neuromuscular effects. These two observations provide visual confirmation of the possible impact of propofol on recovery from a rocuronium neuromuscular blockade.     

Prolonged neuromuscular block after rocuronium in postpartum patients

Postpartum patients have not completely lost the weight gained during pregnancy. Drug dosing according to total body weight (TBW) can cause exaggerated effects and dosing by lean body mass (LBM) may provide a more consistent response despite the increased weight. We compared the duration of a rocuronium neuromuscular block in 22 women undergoing postpartum tubal ligation 31--79 h after delivery, with that in 22 women undergoing gynecological surgery. Anesthesia was induced and maintained with propofol and alfentanil. Half of the patients in each of the Postpartum and Control groups received a bolus dose of rocuronium 0.6 mg/kg TBW and the remaining half received rocuronium 0.6 mg/kg LBM. Neuromuscular block was monitored by electromyography and the ulnar nerve was stimulated transcutaneously using a train-of-four pattern. When rocuronium was given by TBW, median (range) duration of neuromuscular block until 25% recovery of the first twitch response was longer in the Postpartum group, 35.3 (29.7--48.7) min, compared with the Control group, 24.8 (21.5--28.6) min (P < 0.001). After dosing by LBM, the duration of block was similar between groups. The prolonged block with rocuronium in the Postpartum patients can be explained by relative drug overdose when dose calculation is based on their temporarily increased body weight. IMPLICATIONS: Neuromuscular block is prolonged in the postpartum period after standard doses of rocuronium. Drug administration according to lean body mass will produce a more consistent duration of block.     

Spontaneous recovery of neuromuscular function after atracurium in pediatric patients

Spontaneous recovery of neuromuscular function after a bolus dose of 0.40 mg/kg atracurium was assessed in 60 newborn to adolescent patients during balanced anesthesia. Each patient was allowed to recover spontaneously until complete recovery of the single twitch (T1) response and the train-of-four ratio measured from the hypothenar muscle evoked compound EMG. The recovery times of T1 from the onset of relaxation to 10% recovery and to 100% recovery were significantly longer in patients under 10 kg of body weight than in the heavier patients (25 and 56 min vs 19 and 45 min, respectively, P less than 0.01). The rate of recovery, calculated as the recovery index (time between 25% recovery and 75% recovery of T1) was significantly longer in patients under 2 months of age than in older infants or children and adolescents. Atracurium remains, nevertheless, a relaxant of intermediate duration of action even in small infants.     

Residual neuromuscular blockade after cardiac surgery: pancuroniumvs rocuronium

Purpose

To determine the incidence of residual neuromuscular blockade after cardiac surgery in patients receiving either rocuronium or pancuronium for muscle relaxation.

Methods

In a prospective, controlled, double-blind study, 20 patients undergoing coronary artery bypass were randomized to receive either rocuronium (n= 10) or pancuronium (n = 10) dunng surgery. Anaesthesia was induced with sufentanil, benzodiazepine and propofol or ketamine, and maintained with air/O₂/sufentanil/isoflurane. Neuromuscular blockade was induced with 0.1 ml·kg^?1 from blinded synnges containing rocuronium (6 mg·ml^?1) (Group R) or pancuronium (I mg·ml^?1) (Group P). Relaxants were administered according to clinical criteria and reversal agents were not given. After surgery, neuromuscular transmission was assessed by train-of-four stimulation of the ulnar nerve/adductor pollicis EMG (Datex Relaxograph). Mean values from three trains of stimuli were recorded and repeated 30 min later if TOF ratio was < 0.7. Time to extubation was recorded.

Results

On arrival in the ICU, nine of 10 patients in group R but only three of 10 patients in group P demonstrated four visible responses (P < 0.05). Mean TOF ratio in group P, 0.03 ± 0.05, was less than in group R, 0.68 ± 0.34 (P < 0.001). All patients in group P and 4 of 10 patients in group R had TOF ratio < 0.7 (P = 0.01). Time to extubation in group P (median 18, range 6–48 hr) was not statistically different from that in group R (14, 5–44 hr).

Conclusion

Residual neuromuscular block, TOF ratio < 0.7, is common after cardiac surgery but the incidence is less when pancuronium is replaced by rocuronium.     

Acceleromyography in neonates and small infants: baseline calibration and recovery of the responses after neuromuscular blockade with rocuronium

BACKGROUND: We have evaluated the use of the TOF-Guard (TOF, train-of-four) acceleromyographic thumb responses to ulnar nerve stimulation in neonates and infants and the return of the responses after neuromuscular blockade. METHODS: Baseline acceleromyographic recording of thumb adduction to ulnar nerve stimulation during volatile anaesthesia was performed in 22 babies aged less than 30 weeks. At the start of stimulation the automatic set-up procedure of the TOF-Guard was used to see if a 100% control twitch height could be achieved. Irrespective of the ability to achieve a 100% control twitch height, TOF stimulation was used thereafter. When no automatic 100% control twitch could be reached, the transducer signal gain factor was set manually to obtain a 100% value. In 14 of the 22 children the recovery after neuromuscular blockade with rocuronium 0.3 mg kg(-1) was recorded. RESULTS: In nine of 22 patients a 100% baseline twitch height was obtained with the automatic set-up. In the other 13 babies the TOF-Guard display indicated that the transducer signal was too low. The mean time to recovery of control twitch to 75% of baseline after rocuronium 0.3 mg kg(-1) was 51 min (SD = 21) and the time to recovery of the TOF ratio to 70% was 49 min (SD = 19). The mean final twitch height and TOF after recovery from rocuronium blockade were 101% (SD = 15) and 92% (SD = 12), respectively. CONCLUSION: The recovery of the responses after neuromuscular blockade to near baseline values shows that acceleromyography can be used to measure neuromuscular block and recovery in neonates and infants.     

Predicting recovery from deep neuromuscular block by rocuronium in children and adults

STUDY OBJECTIVE: To compare the response to motor nerve stimulation at a rate of 1 Hz after 50 Hz tetanus [posttetanic count (PTC)] and 2 Hz for 2 seconds [train-of-four (TOF)] in children and adults during spontaneous recovery from blockade caused by rocuronium. DESIGN: Prospective, clinical, observational, multicenter study. SETTING: Operating rooms of two university hospitals. PATIENTS: 22 children (ASA physical status I and II) aged 2 to 5 years, scheduled to undergo dental treatment and 20 adults aged 18 to 60 years, scheduled to undergo elective general or orthopedic surgery during general anesthesia with tracheal intubation. MEASUREMENTS: Neuromuscular blockade was evaluated with accelerometry of the thumb, using PTC and TOF stimulation of the ulnar nerve, in patients who received rocuronium 1 mg x kg(-1). MAIN RESULTS: The first response to posttetanic and TOF nerve stimulation appeared earlier in children than in adults. The time from injection of rocuronium to appearance of the fourth response to TOF ranged from 27 to 62 minutes in children and from 37 to 94 minutes in adults. The average interval between the appearance of a posttetanic response and the first detectable response to TOF stimulation (T1) was also shorter in children, 7 minutes, than in adults, 16 minutes. The relationship between PTC and the time interval between a given PTC and the first detectable TOF response in both children and adults was exponential (R = -0.64 and R = -0.81, respectively). CONCLUSIONS: Children recover faster than adults from neuromuscular blockade after administration of 1 mg x kg(-1) rocuronium. The relationship between PTC and time to first response to TOF is exponential both in children and adults during recovery from neuromuscular blockade caused by rocuronium.     

Extremely prolonged neuromuscular block after a single dose of rocuronium

Postoperative curarization in patients has been established. Nevertheless, extremely prolonged neuromuscular blockades are rare. We report the case of a prolonged neuromuscular blockade (lasting 10 hours) following a single dose of rocuronium, in an elderly patient with severe renal failure. We have studied the possible causes of prolonged curarization, and discussed the interest of the use of sugammadex in such cases.     

Extremely prolonged neuromuscular blockade after rocuronium: a case report

It is known that the duration of rocuronium action can be prolonged in elderly patients and that such action shows important interindividual variability. We report a case of prolonged neuromuscular block lasting 11 h, in a woman subjected to kidney transplantation. The possible causes of such prolonged action, inherent to the drug, or related to external factors, are commented.     

Retrospective analysis of spontaneous recovery from neuromuscular blockade produced by empirical use of rocuronium

Purpose  

A train-of-four ratio (TOF ratio) of >0.9 should be the clinical cut-off to avoid residual paralysis. However, it is not rare to extubate patients without measurement of the TOF ratio, although the safe interval from the last administration of rocuronium assuring a TOF ratio of >0.9 has not been established in the daily clinical setting. In this study, to estimate the safe interval to avoid residual paralysis, we retrospectively selected patients in whom the TOF ratio was measured during remifentanil administration before extubation, and we studied the characteristics of recovery from the neuromuscular blockade produced by the empirical use of rocuronium.     

GLP-2alpha accelerates recovery of mucosal absorptive function after intestinal ischemia/reperfusion

BACKGROUND/PURPOSE: The authors' previous laboratory results have shown that rats treated for 3 days with intravenous GLP-2alpha, a synthetic protease-resistant form of glucagonlike peptide-2, showed increased mucosal mass and absorptive function when compared with saline-treated controls after intestinal ischemia/reperfusion (I/R). This study was designed to explore the temporal relationship between injury that occurs secondary to intestinal I/R and recovery of mucosal absorptive function with and without GLP-2alpha treatment. METHODS: Each of 18 male Sprague-Dawley rats (300 to 333 g) was subjected to superior mesenteric artery occlusion for 30 minutes, during which time a jugular venous catheter was placed and connected to a subcutaneous infusion pump. Rats were divided into 4 groups based on the type and duration of infusion as follows: group 1, systemic saline at 1 microL/h for 24 hours (n = 5); group 2, systemic GLP-2alpha at 100 microg/kg/d for 24 hours (n = 5); group 3, systemic saline at 1 microL/h for 72 hours (n = 4); and group 4, systemic GLP-2alpha at 100 microg/kg/d for 72 hours (n = 4). Immediately after the infusions, (14)C-galactose and (14)C-glycine absorption was measured using an in vivo, closed-recirculation technique and expressed as micromoles per square centimeter intestine +/- SEM. Statistical analysis was performed using analysis of variance. RESULTS: Twenty-four hours after intestinal I/R injury, there was a decrease in substrate absorption but no significant difference between the saline and GLP-2alpha-treated groups (galactose absorption, 1.13 +/- 0.09 in group 1 v 1.35 +/- 0.11 in group 2, P =.15; glycine absorption, 1.18 +/- 0.13 in group 1 v 1.34 +/- 0.15 in group 2, P =.36). However, after the 72-hour infusion, absorption of galactose and glycine was significantly increased in the rats receiving GLP-2alpha as compared with the saline-infused control group (galactose absorption, 1.24 +/- 0.13 in group 3 v 1.88 +/- 0.10 in group 4, P <.01; glycine absorption, 1.64 +/- 0.07 in group 3 v 2.05 +/- 0.08 in group 4, P <.05). Compared with previously determined levels of absorption in normal, uninjured rat intestine (1.50 +/- 0.12 micromol/cm(2) for galactose and 1.85 +/- 0.17 micromol/cm(2) for glycine), after I/R a 72-hour infusion of GLP-2alpha increased galactose absorption 26% (P <.05) and glycine absorption 11% (P =.29) beyond baseline. CONCLUSIONS: When initiated at the time of intestinal I/R, a continuous infusion of GLP-2alpha accelerated recovery of mucosal absorptive function in rats. Remarkably, carbohydrate absorption at 72 hours was increased to a level significantly greater than that in normal, uninjured rat intestine. J Pediatr Surg 36:570-572.