Rocuronium Concentration Research Articles

The Relationship between the Measured Blood Concentration of Rocuronium in Stable Muscle Relaxation with a Closed-Loop Control and the Estimated Blood Concentration from a Pharmacokinetic Simulation.

We developed a system to adjust the rate of a continuous rocuronium (Rb) infusion to achieve 3 ≤ %T1 ≤ 10 with a closed-loop control. Samples were collected from 15 patients, and Rb blood concentrations were measured at the following time points: (1) when %T1 recovered to 3% or more after the initial Rb infusion; (2) when %T1 stabilized within the target range; (3) at the cessation of the Rb infusion; (4) 5 min after the sugammadex administration. The predicted Rb blood concentration at each time point was calculated and recorded using the pharmacokinetic parameters of Wierda et al. At time points (1), (2), and (3), the predicted blood concentrations were in good agreement with the measured values, but after the administration of sugammadex, the blood concentrations were higher than the predicted values because the Rb distributed in the tissues migrated into the blood. From the above, it was confirmed that the predicted blood concentration of Rb can be a good indicator for the automatic Rb administration control.

Comparison between conventional-dose and high-dose rocuronium use in general anesthesia for Cesarean section.

Background: There have been few studies comparing the effects of high- and low-dose rocuronium during cesarean section by directly measuring the concentration. Therefore, we conducted a study to examine the blood concentrations and clinical effects of both doses of rocuronium on mothers and fetuses. Methods: Eighteen patients were randomly assigned to two groups: C Group (0.6 mg/kg), and H Group, (1.0 mg/kg). The primary outcome was the comparison of umbilical vein rocuronium concentration between two groups. We assessed ease of intubation, time from rocuronium administration to some TOF points, post-anesthesia care unit (PACU) stay time, infused remifentanil dose, maternal rocuronium concentration, and Apgar scores. Results: No differences were observed in demographic data, ease of intubation, PACU stay time, 1 min Apgar scores, umbilical venous blood gas analysis between both groups. However, the time from rocuronium administration to T3 disappearance was shorter (p=0.009) and time to T1 and T2 reappearance were longer (p=0.003, p=0.009) in H group than that in C group. The administered remifentanil dose (p=0.042) was lower in the H group than in the C group. Rocuronium concentrations in the umbilical vein (p=0.004) and maternal vein before cord clamping (p=0.002) and at discharge (p<0.001) were also found to be higher in the H group than in the C group. Conclusions: We observed no prolongation of PACU stay, and no differences in Apgar scores in H group compared to C group. It suggests that 1.0 mg/kg of rocuronium has no negative effects on the fetus and mother in cesarean section.

Effect of intraoperative muscle relaxation reversal on the success rate of motor evoked potential recording in patients undergoing spinal surgery: a randomized controlled trial

BackgroundPartial neuromuscular blockade (NMB) has been applied for some surgeries to reduce bleeding and prevent patient movement for spinal surgery. Sugammadex selectively binds to rocuronium in the plasma and consequently lowers the rocuronium concentration at the neuromuscular junction. In this study, we aimed to observe whether the success rate of transcranial motor-evoked potential (TceMEP) can be increased by sugammadex compared with partial NMB during spinal surgery.MethodsPatients who underwent elective spinal surgery with TceMEP monitoring were randomly assigned to the sugammadex group and control group. Rocuronium was continuously infused to maintain the train of four counts (TOFc) = 2. The sugammadex group discontinued rocuronium infusion at the time of TceMEP monitoring and was infused with 2 mg/kg sugammadex; the control group was infused with the same dose of saline.ResultsA total of 171 patients were included. The success rate of TceMEP monitoring in the sugammadex group was significantly higher than that in the control group. TceMEP amplitudes were greater in the sugammadex group than in the control group at 5 min, 10 min, and 20 min after the start of motor-evoked potential monitoring. The latencies of upper extremity TceMEPs monitoring showed no difference between groups. TOF ratios were greater in the sugammadex group at 5 min, 10 min, and 20 min after the start of motor-evoked potential monitoring. There were no adverse effects caused by sugammadex.ConclusionsSugammadex can improve the success rate of motor-evoked potential monitoring compared with moderate neuromuscular blockade induced by continuous infusion of rocuronium in spinal surgery.Trial registrationThe study was registered on clinicaltrials.gov.cn on 29/10/2020 (trial registration number: NCT04608682).

Influence of the Pringle maneuver during partial hepatectomy on the neuromuscular block induced by intermittent and continuous dosing of rocuronium.

The Pringle maneuver (PM) is a common procedure in hepatectomy that is known to interrupt drug elimination. The purpose of this study was to examine the influence of PM on the duration of action of rocuronium administered by intermittent bolus dosing, the continuous rocuronium infusion dose required for maintenance of a moderate neuromuscular block, and changes in plasma concentrations of rocuronium. Twenty-seven adult patients undergoing partial hepatectomy with PM were enrolled in this study. The duration of action of 0.2mg/kg rocuronium boluses (DUR), and the continuous rocuronium infusion dose required for maintenance of the height of the first twitch of the train-of-four (T1) at 10-20% of the control value (%T1), respectively, were electromyographically monitored on the adductor digiti minimi muscle. The effects of PM on DUR, %T1, and the plasma concentration of rocuronium were measured. The DUR was significantly prolonged during PM [mean: 42.2 (SD: 8.0) min, P < 0.001] compared to baseline [29.7 (6.3) min]. It was prolonged even after completion of the PM [46.2 (10.5) min, P < 0.001]. The plasma concentration of rocuronium measured at every reappearance of T1 was comparable between before and during PM. %T1 [15.5 (5.6)%] was significantly depressed after the start of PM [6.5 (3.9)%, P < 0.001], with persistence of the depression even after completion of PM. However, there were no significant changes in the plasma concentration of rocuronium. Rocuronium-induced neuromuscular block is significantly augmented during PM. However, the augmentation is not associated with an increase in plasma rocuronium concentration.

Effect-Site Concentration of Rocuronium at the Time of Recovery and Risk of Recurarization in the Presence of Antagonism of Neuromuscular Block by Sugammadex

Effect-Site Concentration of Rocuronium at the Time of Recovery and Risk of Recurarization in the Presence of Antagonism of Neuromuscular Block by Sugammadex

Plasma rocuronium concentration in cell salvage blood following cardiac surgery: a case series

The aim of the study was to evaluate the plasma rocuronium concentration in autologous blood transfusion obtained from the cell salvage (CS) system following cardiac surgery with cardiopulmonary bypass (CPB). This prospective observational study was conducted in a university teaching hospital from July to November 2020. Patients undergoing general anesthesia for cardiac surgery with CPB were enrolled in the study. After separation from CPB, residual blood remaining in the extracorporeal system was collected as the control sample. The second sample (CS blood) was collected from the autologous blood transfusion obtained after completion of the CS system with Cell Saver® Elite®. Hematocrit values of both samples were also examined. Ten subjects (aged 57-86years) were enrolled in this study. Plasma rocuronium concentrations (ng/ml) were significantly lower in the CS blood (94.0 ± 77.5) compared to the control (2950 ± 812.2) (p = 0.002). Hematocrit values (%) were significantly higher in the CS blood (75.2 ± 11.3) compared to the control (40.2 ± 10.2) (p = 0.002). Autologous blood transfusion obtained from CS system following cardiac surgery with CPB, only retained a small amount of plasma rocuronium concentration, therefore, the risk of autologous blood transfusion contributing to clinically relevant residual neuromuscular blockade postoperatively should be considered to be low. This trial was registered in the University Hospital Medical Information Network under registration number UMIN000040877 (registration date; June 24, 2020).

Extravascular leakage of induction doses of rocuronium: four cases in which both depth of neuromuscular block and plasma concentration of rocuronium were assessed.

The duration of action of extravasated rocuronium varies depending on the patient's comorbidities. In patients who receive high doses of non-depolarizing neuromuscular blocking agents subcutaneously, anesthesiologists should be aware of unexpected prolongation of the progress and recovery of neuromuscular block. In such cases, the depth and recovery of neuromuscular block should be objectively monitored to avoid residual neuromuscular block and recurarization.

The effect of cold-chain re-introduction on the molecular integrity of rocuronium bromide

Introduction: This study aimed to examine the effect of breakages and re-introduction into cold chain on the rocuronium bromide compound. Rocuronium bromide is frequently used in routine theatre lists and plays a vital role in modified rapid sequence induction and intubation for emergency patients who have contraindications to the primarily used muscle relaxant, succinylcholine. With the current practice of removing the drug from, and then reintroducing it into the cold chain, unpredictable clinical effects, including delayed onset of action and shortened duration of action have been observed. This may pose significant risks to the patient. Methods: Rocuronium bromide was subjected to different clinically applicable storage and temperature scenarios, after which the compound was analysed for integrity and quantities of the active compound, including detection of possible degradation products, by mass spectrometry, and compared to cold chain control samples. Results: There were no significant differences between any of the temperature exposure groups (18 °C or 24 °C) or between single or double exposures at these temperatures. No statistically significant difference could be demonstrated between the two control groups (cold chain preserved and room temperature controlled) with testing done at weeks one and six. However, week twelve analysis revealed a statistically significant result which translates to a 26 μg/ml difference, which clinically would have no effect. Substantial results were obtained with a secondary exposure to air; which lead to a 20% decrease in rocuronium concentration (p = 0.02). Conclusion: Practice should be adapted by keeping careful documentation as to when cold-chain was broken, and when the recommended 12 week period will lapse. Vial sharing as a standard is not recommended. If small quantities are repeatedly withdrawn from the vial during a prolonged case, the unused contents should be discarded after eight hours.

Effects of hyperthermia on the effective concentration of rocuronium and sugammadex-mediated reversal in isolated phrenic nerve hemidiaphragm preparations of rats

BackgroundHyperthermia is relatively rare during general anesthesia; however, a few studies have been conducted on hyperthermia and the neuromuscular blockade (NMB) induced by rocuronium, and the reversal of NMB by sugammadex. We investigated the effect of hyperthermia status on the NMB induced by rocuronium, and its reversal by sugammadex, in isolated phrenic nerve hemidiaphragm (PNHD) preparations of the rat.MethodsThirty-three male Sprague-Dawley rat PNHD preparations were randomly assigned to three groups at different temperatures (36 °C, 38 °C, and 40 °C; each group, n = 11, in Krebs solution). The train-of-four (TOF) and twitch height responses were checked mechanomyographically. The PNHD were treated with progressively increasing doses of rocuronium and three effective concentrations (ECs), EC50, EC90, and EC95, of rocuronium were analyzed in each group via nonlinear regression analysis. Then, sugammadex was administered in doses equimolar to rocuronium. Thereafter, the T1 height (%), TOFR (%) and the duration index were measured.ResultsThe EC of rocuronium (EC50, EC90, and EC95) decreased significantly in accordance with increasing temperature. The groups at 36 °C and 40 °C showed clear differences in all areas (all P < 0.001). Moreover, the T1 height (%) and the duration index upon sugammadex administration showed faster recovery results in the36 °C than the 38 °C and 40 °C groups.ConclusionA rise of temperature from 38 °C to 40 °C in rat PNHD preparations proportionally enhanced the NMB induced by rocuronium. In addition, equimolar doses of sugammadex to the administered rocuronium showed a slower recovery time as the temperature rises.

The effect of magnesium sulfate concentration on the effective concentration of rocuronium, and sugammadex-mediated reversal, in isolated left phrenic nerve hemi-diaphragm preparations from the rat.

BackgroundPerioperative magnesium sulfate (MgSO4) is used for analgesic, anti-arrhythmic, and obstetric purposes. The effects of MgSO4 on the neuromuscular blockade (NMB) induced by rocuronium, and the sugammadex reversal thereof, have not been clearly quantified. We investigated the effect of various MgSO4 concentrations on the NMB by rocuronium, and sugammadex reversal, in isolated left phrenic nerve hemi-diaphragm (PNHD) preparations from the rat.MethodsRat PNHD preparations were randomly allocated to one of four groups varying in terms of MgSO4 concentration (1, 2, 3, and 4 mM, each n = 10, in Krebs solution). The train-of-four (TOF) and twitch height responses were recorded mechanomyographically. The preparations were treated with incrementally increasing doses of rocuronium and each group’s effective concentration (EC)50, EC90, and EC95 of rocuronium were calculated via nonlinear regression. Then, sugammadex was administered in doses equimolar to rocuronium. The recovery index, time to T1 height > 95% of control, and the time to a TOF ratio > 0.9 after sugammadex administration were measured.ResultsThe EC50, EC90, and EC95 of rocuronium fell significantly as the magnesium level increased. The EC50, EC90, and EC95 of rocuronium did not differ between the 3 and 4 mM groups. The recovery index, time to T1 height > 95% of control, and time to a TOF ratio > 0.9 after sugammadex administration did not differ among the four groups.ConclusionsIncreases in the magnesium concentration in rat PNHD preparations proportionally enhanced the NMB induced by rocuronium but did not affect reversal by equimolar amounts of sugammadex.

Effects of magnesium chloride on rocuronium-induced neuromuscular blockade and sugammadex reversal in an isolated rat phrenic nerve-hemidiaphragm preparation: An in-vitro study.

Magnesium potentiates the effects of nondepolarising muscle relaxants. However, few studies have used magnesium chloride (MgCl2). Sugammadex reverses neuromuscular block by steroidal nondepolarising muscle relaxants. To assess the effects of MgCl2 on rocuronium-induced neuromuscular blockade and its reversal by sugammadex. In-vitro experimental study. Animal laboratory, Asan Medical Center, Seoul, South Korea, from 20 March 2016 to 3 April 2016. Forty male Sprague Dawley rats. Left phrenic nerve-hemidiaphragms from 40 Sprague Dawley rats were allocated randomly to four groups (1, 2, 3 and 4 mmol l MgCl2 group, n = 10 each). Rocuronium was administered cumulatively until the first twitch of train-of-four (TOF) disappeared completely. Then, equimolar sugammadex was administered. The effective concentration (EC) of rocuronium was obtained in each group. After administering sugammadex, recovery of the first twitch height and the TOF ratio were measured for 30 min. EC50, EC90 and EC95 significantly decreased as the concentration of MgCl2 increased (all P ≤ 0.001), except the comparison between the 3 and 4 mmol l MgCl2 groups. After administration of sugammadex, the maximal TOF ratio (%) was lower in the 4 mmol l MgCl2 group than the 1 mmol l MgCl2 group [median 91.7 interquartile range (83.4 to 95.8) vs. 98.3 interquartile range (92.2 to 103.4), P = 0.049]. The mean time (s) from sugammadex injection to achieving maximal first twitch was significantly prolonged in the 4 mmol l MgCl2 group vs. the 1 mmol l MgCl2 and 2 mmol l MgCl2 groups [1483.9 (± 237.0) vs. 1039.0 (± 351.8) and 926.0 (± 278.1), P = 0.022 and 0.002, respectively]. Increases in MgCl2 concentration reduce the ECs of rocuronium. In addition, administering sugammadex equimolar to the administered rocuronium shows limited efficacy as MgCl2 concentration is increased. The in-vitro study was not registered in a database.

Influence of preoperative oral rehydration on arterial plasma rocuronium concentrations and neuromuscular blocking effects: A randomised controlled trial.

The influence of preoperative rehydration on the action of rocuronium has not yet been investigated. The objective is to evaluate the hypothesis that preoperative rehydration lowers arterial rocuronium plasma concentrations and changes its associated neuromuscular blocking effects during induction of anaesthesia. Randomised, single-blinded study. A secondary hospital from October 2013 to July 2014. In total, 46 men undergoing elective surgery were eligible to participate and were randomly allocated into two groups. Exclusion criteria were severe hepatic, renal or cardiovascular disorder; neuromuscular disease; history of allergy to rocuronium; BMI more than 30 kg m; receiving medication known to influence neuromuscular function. Participants received 1500 ml of oral rehydration solution (rehydration group) or none (control group) until 2 hours before anaesthesia. Arterial blood samples were obtained 60, 90 and 120 s and 30 min after rocuronium (0.6 mg kg) administration during total intravenous anaesthesia. Responses to 0.1-Hz twitch stimuli were measured at the adductor pollicis muscle using acceleromyography. Arterial plasma rocuronium concentrations. Arterial plasma rocuronium concentrations at 60, 90 and 120 s in the rehydration and control groups were 9.9 and 13.7, 6.8 and 9.5 and 6.2 and 8.1 μg ml, respectively (P = 0.02, 0.003 and 0.02, respectively); the onset times in the rehydration and control groups were 92.0 and 69.5 s (P = 0.01), and the times to twitch re-appearance were 25.3 and 30.4 min (P = 0.004), respectively. Preoperative rehydration significantly reduces arterial plasma rocuronium concentrations in the first 2 minutes after administration, prolonging the onset time and shortening the duration of effect. A higher dose or earlier administration should be considered for patients who receive preoperative rehydration. Umin identifier: UMIN000011981.

Ultrasound-Guided Thoracic Paravertebral Block Experience in a Child.

Ultrasound-Guided Thoracic Paravertebral Block Experience in a Child.

Effective method of continuous rocuronium administration based on effect-site concentrations using a pharmacokinetic/pharmacodynamic model during propofol-remifentanil anesthesia.

Rocuronium bromide (Rb) is a rapid onset, intermediate-acting neuromuscular blocking agent that is suitable for continuous administration. The appropriate rate of rocuronium administration is, however, difficult to determine due to large interindividual differences in sensitivity to rocuronium. The aim of this study was to clarify whether the simulated rocuronium concentration at the time of recovery to %T1 > 0 % after the initial administration of rocuronium is a good indicator of optimal effect-site concentrations during continuous rocuronium administration. Twenty-one patients were anesthetized with propofol. After induction, Rb 0.6 mg/kg was administered intravenously, and nerve stimulation using the single stimulation mode was conducted every 15 s. When %T1 recovered to >0 % after the initial administration of Rb, the effect-site concentration of rocuronium, calculated by pharmacokinetic simulation with Wierda's set of parameters, was recorded and defined as the recovery concentration (Rb r.c.). The administration rate of rocuronium was adjusted to maintain the Rb r.c. during surgery. Rb administration was discontinued just before the end of surgery, and the recovery time until %T1 > 25 % was recorded. Plasma Rb concentrations were measured at 1 and 3 h after the initiation of continuous Rb administration. The mean Rb r.c. was 1.56 ± 0.35 μg/ml, with minimum and maximum values of 1.09 and 2.08 μg/ml, respectively. The %T1 did not increase above 10 % in any of the patients during continuous administration of Rb, and the recovery period to %T1 > 25 % ranged from 9 to 29 min. The effect-site concentrations of Rb calculated with Wierda's parameters significantly correlated with plasma concentrations (P < 0.01) at both 1 and 3 h after the initial administration of Rb. The results suggest that our method may be one of the most reliable protocols for the continuous administration of Rb described to date for maintaining suitable muscle relaxation during surgery without excessively prolonged effects.

The effect of high concentration of magnesium with ropivacaine, gentamicin, rocuronium, and their combination on neuromuscular blockade.

BackgroundMagnesium, ropivacaine, gentamicin, and rocuronium block neuromuscular (NM) transmission by different mechanisms. Therefore, concurrent administration of these agents may induce prolonged muscle paralysis via synergistic interaction. This study investigated the efficacy and safety of NM block caused by the administration of high concentrations of magnesium in combination with ropivacaine, gentamicin, and rocuronium.MethodsEighty-three left phrenic nerve-hemidiaphragms from male SD rats (150-250 g) were hung in Krebs solution. Three consecutive single twitch tension (ST, 0.1 Hz) and one tetanic tension (TT, 50 Hz for 1.9 s) were obtained before drug application and at each new drug concentration. The concentration of MgCl2 and MgSO4 in Krebs solution was increased until an 80 to 90% reduction in ST was reached. To test the effects of combinations of NM agents, a Krebs solution was premixed with MgCl2 alone, MgCl2 and ropivacaine, or MgCl2, ropivacaine, and gentamicin. The concentration of ropivacaine, gentamicin, or rocuronium was then progressively increased until an 80 to 90% reduction in ST was reached. The effective concentrations were estimated with a probit model.ResultsThe potency of MgCl2 was greater than that of MgSO4, and pretreatment with MgCl2 increased the potency of gentamicin and rocuronium. Unexpectedly, MgCl2 did not potentiate ropivacaine, and the potency of gentamicin and rocuronium failed to show an increase when premixed with 0.5 µM ropivacaine.ConclusionsThe concomitant administration of high concentrations of magnesium and ropivacaine together with clinically relevant concentrations of gentamicin or rocuronium potentiated NM blockade but not with clinically relevant concentrations of ropivacaine.

Interaction of rocuronium with human liver cytochromes P450

Rocuronium is a neuromuscular blocking agent acting as a competitive antagonist of acetylcholine. Results of an inhibition of eight individual liver microsomal cytochromes P450 (CYP) are presented. As the patients are routinely premedicated with diazepam, possible interaction of diazepam with rocuronium has been also studied.Results indicated that rocuronium interacts with human liver microsomal CYPs by binding to the substrate site. Next, concentration dependent inhibition of liver microsomal CYP3A4 down to 42% (at rocuronium concentration 189 μM) was found. This effect has been confirmed with two CYP3A4 substrates, testosterone (formation of 6β-hydroxytestosterone) and diazepam (temazepam formation). CYP2C9 and CYP2C19 activities were inhibited down to 75–80% (at the same rocuronium concentration). Activities of other microsomal CYPs have not been inhibited by rocuronium.To prove the possibility of rocuronium interaction with other drugs (diazepam), the effect of rocuronium on formation of main diazepam metabolites, temazepam (by CYP3A4) and desmethyldiazepam, (also known as nordiazepam; formed by CYP2C19) in primary culture of human hepatocytes has been examined. Rocuronium has caused inhibition of both reactions by 20 and 15%, respectively.The results open a possibility that interactions of rocuronium with drugs metabolized by CYP3A4 (and possibly also CYP2C19) may be observed.

Which is more useful to non-obese patients (BMI&lt; 30) undergoing tracheal intubation, T1% of the corrugator supercilii muscle or effect site concentration of rocuronium calculated by iPad application AnestAssist?

Which is more useful to non-obese patients (BMI&lt; 30) undergoing tracheal intubation, T1% of the corrugator supercilii muscle or effect site concentration of rocuronium calculated by iPad application AnestAssist?

Influence of obstructive jaundice on neuromuscular blocking effect and drug metabolism of rocuronium

Objective To observe the effect of obstructive jaundice on the neuromuscular blocking effect and drug metabolism of rocuronium,so as to guide proper use of rocuronium during anesthesia for patients undergoing hepatobiliary surgeries.Methods Thirty patients(with normal renal function and without muscle or nerves diseases,ASAⅠ-Ⅱ)receiving elective surgery were divided into 2groups:obstructive jaundice group(group Ⅰ,n=15)and control group(group Ⅱ,n=15).All patients received continuous peridural anesthesia and general anesthesia.Neuromuscular blockade was evaluated with train-of-four(TOF)stimuli of the ulnsar nerve using TOF Watch SX nerve stimulators.The onset time,clinical duration of rocuronium,the time of TOFR from 0 to 70% and recovery index(T1 from 25%-75%) were observed. Liquid chromatography-tandem mass spectrometry(LC/MS/MS)was used to determine the concentration of rocuronium in the plasma at 30,60,90,120,and 180 min after administration of 0.9 mg/kg rocuronium.Results The age,body mass index,and prothrombin time were matched between the two groups.The total bilirubin,direct bilirubin and indirect bilirubin in groupⅠ were significantly higher than that in group Ⅱ(P<0.01).The onset time was similar between the two groups;the clinical duration of rocuronium,the time of TOFR from 0to 70%,and the recovery index(to 10%,25%,50%,and 75% of T1)in groupⅠ were significantly longer than those in groupⅡ(P<0.01).The plasma concentrations of rocuronium in groupⅠ were significantly higher than those in group Ⅱat 60,90,120 min after administration of rocuronium(P<0.01 or P<0.05).Conclusion Obstructive jaundice may prolong the duration of rocuronium action and recovery time,and slows down themetabolism of rocuronium.So patients with obstructive jaundice should have a longer interval for drug addition.Peri-and postoperative monitoring of neuromuscular function is suggested for proper drug use and anesthesia extubation.

Sevoflurane versus propofol for interventional neuroradiology: a comparison of the maintenance and recovery profiles at comparable depths of anesthesia.

BackgroundSevoflurane and propofol are used widely for interventional neuroradiology (INR). Using the bispectral index (BIS), we compared the clinical properties of sevoflurane and propofol anesthesia in patients undergoing INR at comparable depths of anesthesia.MethodsThe patients were allocated randomly into two groups. The sevoflurane group received propofol (1.5 mg/kg), alfentanil (5 µg/kg), and rocuronium (0.6 mg/kg) for induction, and the propofol group was induced with a target effect-site concentration of propofol (4 µg/ml), alfentanil (5 µg/kg), and rocuronium (0.6 mg/kg). After intubation, anesthesia was maintained with sevoflurane or propofol with 67% nitrous oxide in 33% oxygen. Sevoflurane and propofol concentrations were titrated to maintain the BIS at 50-60. Phenylephrine or opioid was used to maintain the mean arterial pressure within 20% of the baseline values. The amounts of phenylephrine or alfentanil used, the number of patients showing movement during the procedure, and the recovery times were recorded.Results Compared to the propofol group, the sevoflurane group showed faster recovery in spontaneous ventilation, eye opening, extubation, and orientation (4 vs. 7 min, 7 vs. 9 min, 8 vs. 10 min, 10 vs. 14 min, respectively; P < 0.01). In the propofol group, significantly greater amounts phenylephrine were used (P < 0.05), and more patients moved during the procedure (P < 0.05).ConclusionsThe use of sevoflurane in maintaining anesthesia during INR was associated with faster recovery, less patient movement during the procedure, and a more stable hemodynamic response when compared to propofol.

Do bupivacaine, clindamycin, and gentamicin at their clinical concentrations enhance rocuronium-induced neuromuscular block?

BackgroundBupivacaine, clindamycin, and gentamicin inhibit neuromuscular (NM) conduction. When they are combined, they may synergistically reduce the effective concentration of each to the therapeutic concentration in augmenting rocuronium-induced NM block. Thus, the aim of this study was to investigate whether combinations of the three drugs, at around their therapeutic concentrations, potentiate rocuronium-induced NM block.MethodsFifty-seven left-phrenic nerve hemidiaphragms (Male S-D rats, 150-250 g) were hung in a 20-ml organ bath filled with Krebs solution. Three consecutive single-twitch tensions (0.1 Hz) and one tetanic tension (50 Hz for 1.9 s) were obtained. A Krebs solution was premixed with concentration sets of bupivacaine and clindamycin, bupivacaine and gentamicin, or bupivacaine, clindamycin and gentamicin. Then, the concentration of rocuronium was cumulatively increased in the Krebs solution (1, 3, 5, 7, 9, 12, 14, 16, 18, and 20 µM) until an 80% to 90% reduction in single twitch was attained. The effective concentrations for each experiment were determined with the probit model.ResultsThe combinations of bupivacaine, clindamycin, and gentamicin enhanced rocuronium-induced NM block. When the three drugs were applied simultaneously, their concentrations were reduced to near-therapeutic levels in potentiating the action of rocuronium.ConclusionsBupivacaine, clindamycin, and gentamicin blocked NM conduction, and when all three drugs were applied together, they augmented rocuronium-induced NM block at their near-therapeutic concentrations. Clinicians should be aware of the cooperability in NM block between drugs that interrupt NM conduction.