Clinical pharmacokinetics of rocuronium bromide

Impact of anesthesia drugs on digestive motility measurements in humans: A systematic review

BACKGROUND AND PURPOSE

Measurement of gastro-intestinal motility is increasingly performed under general anesthesia during endoscopic or surgical procedures. The aim of the present study was to review the impact of different anesthetic agents on digestive motility measurements in humans.

METHODS

This systematic review was performed using the Medline-Pubmed and Web of Science databases. All articles published until October 2023 were screened by identification of key words. Studies were reviewed if patients had an assessment of digestive motility using conventional perfused manometry, high-resolution manometry, electronic barostat or functional lumen impedance planimetry with the use of inhaled or intravenous anesthetic anesthetic agents (propofol, ketamine, halogens, nitrous oxide, opioids, and neuromuscular blockades).

RESULTS

Four hundred and eighty-eight unique citations were identified, of which 42 studies met the inclusion criteria and were included in the present review. The impact of anesthetics was mostly studied in patients who underwent esophageal manometry. There was a heterogeneity in both the dose and timing of administration of anesthetics among the studies. Remifentanil analgesia was the most studied anesthetic drug in the literature, showing a decrease in both distal latency and lower esophageal sphincter pressure after its administration, but the impact on Chicago classification was not studied. Inhaled anesthetics administration elicited a decrease in lower esophageal sphincter pressure, but contradictory findings were shown on esophageal motility following propofol or neuromuscular blocking agents administration.

CONCLUSION

Studies of the impact of anesthetics on digestive motility remain scarce in the literature, although some agents have been reported to profoundly affect gastro-intestinal motility.

Optimizing anesthesia strategies to NSCLC patients in VATS procedures: Insights from drug requirements and patient recovery patterns

Understanding the intricate relationship between cancer clinicopathological features and anesthetics dosage is crucial for optimizing patient outcomes and safety during surgery. This retrospective study investigates this relationship in patients with non-small cell lung cancer (NSCLC) undergoing video-assisted thoracic surgery (VATS). A comprehensive analysis of medical records was undertaken for NSCLC patients who underwent VATS with intravenous compound inhalation general anesthesia. Patients were categorized based on histological, chemotherapy, radiotherapy, and epidural anesthesia factors. Statistical analysis was performed to compare the differences between the groups. The results revealed compelling insights. Specifically, patients with lung adenocarcinoma (LUAD) undergoing VATS exhibited higher dosages of rocuronium bromide and midazolam during general anesthesia, coupled with a shorter post-anesthesia care unit (PACU) stay compared to those with squamous cell carcinoma (sqCL). Furthermore, chemotherapy patients undergoing VATS demonstrated diminished requirements for phenylephrine and remifentanil in contrast to their non-chemotherapy counterparts. Similarly, radiotherapy patients undergoing VATS demonstrated a decreased necessity for rocuronium bromide compared to non-radiotherapy patients. Notably, patients who received epidural anesthesia in combination with general anesthesia manifested reduced hydromorphone requirements and prolonged hospital stays compared to those subjected to general anesthesia alone. In conclusion, the findings from this study indicate several important observations in diverse patient groups undergoing VATS. The higher dosages of rocuronium bromide and midazolam in LUAD patients point to potential differences in drug requirements among varying lung cancer types. Additionally, the observed shorter PACU stay in LUAD patients suggests a potentially expedited recovery process. The reduced anesthetic requirements of phenylephrine and remifentanilin chemotherapy patients indicate distinct responses to anesthesia and pain management. Radiotherapy patients requiring lower doses of rocuronium bromide imply a potential impact of prior radiotherapy on muscle relaxation. Finally, the combination of epidural anesthesia with general anesthesia resulted in reduced hydromorphone requirements and longer hospital stays, suggesting the potential benefits of this combined approach in terms of pain management and postoperative recovery. These findings highlight the importance of tailoring anesthesia strategies for specific patient populations to optimize outcomes in VATS procedures.

Effects of a single dose of rocuronium in patients with different body fat percentages: A randomised controlled trial

The pharmacodynamics in patients with high body fat percentage might be similar to those in obese patients. This randomised controlled clinical trial observed the effects of rocuronium in patients with different percent body fats (PBFs). Fifty-four patients who underwent elective urological or pelvic surgery under general anaesthesia at Shanghai General Hospital were included in the present study; 51 patients were included for data analysis. Patients with normal PBF (<25%) were given a single dose of rocuronium calculated based on total body weight (N-TBW, control group). Patients with a higher PBF (≥25%) were given a single dose of rocuronium calculated based on total body weight (H-TBW). Patients with higher PBF and rocuronium were dosed based on fat-free mass (H-FFM). A train of four (TOF)-Watch acceleromyography monitor was used to measure the effects of the rocuronium. H-TBW (91.9 ± 28.8 s) had significantly shorter onset time than N-TBW and H-FFM (p = 0.003). H-TBW had significantly longer clinical duration time and pharmacological duration time than the other groups (p = 0.000 and 0.000, respectively); the TOF ratio0.25-0.9 time was significantly different among the three groups (p = 0.005). There were no significant differences in the recovery time (p = 0.103) or recovery index (p = 0.159) among the three groups. The effects of rocuronium dosed based on FFM in patients with high PBFs are similar to those in normal patients. A single dose of rocuronium calculated based on TBW might shorten the onset time, prolong the clinical and pharmacological duration times, and prolong the recovery time.

Non-intubated deep paralysis: a new anaesthesia strategy for vocal cord polypectomy

BACKGROUND

Vocal cord polyp is common otorhinolaryngological disease, traditionally treated by vocal cord polypectomy under a supporting laryngoscope with general anaesthesia. Although it is safe and controllable, it would cause some anaesthesia complications. Moreover, the complex process of general anaesthesia may significantly reduce surgical efficiency. Avoiding these problems remains an important issue.

METHODS

All patients were subjected to the standard non-intubated deep paralysis (NIDP) protocol consisting of four phases. An emergency plan was launched when NIDP cannot be implemented successfully. Patient characteristics, blood gas and monitoring data were collected during NIDP. Data concerning satisfaction, complications and duration of anaesthesia and recovery were collected to assess its effectiveness.

RESULT

Among 20 enrolled patients, the success rate of NIDP was 95%. Only one patient failed in completing NIDP. Blood gas analysis revealed that the partial pressure of oxygen and carbon dioxide was maintained at safe levels. Monitoring during NIDP revealed fluctuations in mean arterial pressure between 110 and 70 mmHg, and the heart rate was stable at 60-100 beats per minute. The duration of anaesthesia and postoperative recovery were 13.0 ± 2.84 and 5.47 ± 1.97 min, respectively. All patients and surgeons were satisfied with NIDP, and no complications were detected before discharge.

CONCLUSION

NIDP can be safely applied to patients and can replace general anaesthesia in vocal cord polypectomy. It can significantly reduce the duration of anaesthesia and postoperative recovery. No anaesthesia complications occurred without intubation, and patients and surgeons were satisfied with NIDP.

TRIAL REGISTRATIONS

This single-centre, prospective study was registered on clinicaltrial.gov (NCT04247412) on 30^th July 2020.

Application of neuromuscular blockade using Rocuronium for performing different surgeries and its reversal by Neostigmine-Glycopyrrolate combination in dogs

This study was executed in the clinical setup to investigate the effects of Rocuronium and its reversal by Neostigmine and Glycopyrrolate (Myopyrolate) combination in Propofol-Isoflurane anaesthetized dogs. Rocuronium-induced neuromuscular blockade was applied to 21 clinical cases. Out of which, 19 cases were of orthopaedic surgeries and 2 cases of ovariohysterectomy. After the animal had stabilized on the mixture of isoflurane and oxygen, the relaxation of muscle was induced using Rocuronium @ 0.5 mg/kg b.wt. Immediately IPPV was provided in volume control mode. Neuromuscular blockade was reversed using a single syringe combination drug having both Neostigmine and Glycopyrrolate (Myopyrolate) @ 0.05 mg/kg b.wt and @ 0.01 mg/kg b.wt, respectively. Rocuronium caused the centering of the ocular globe gradually in less than 30 sec. During orthopaedic surgeries, the reduction of fractured ends became easy without much tissue trauma. In ovariohysterectomy surgeries, the appropriate level of abdominal muscle relaxation further helped in the easy exteriorization of the ovarian stump. The onset time for Rocuronium was 17.64±1.10 sec and its duration of action was 27.82±0.72 min. The use of Rocuronium along with IPPV caused minimal alteration of the physiological parameters with no clinical consequences and thus can be considered a complication-free anaesthetic protocol for interventions demanding muscle relaxation.

Neuromuscular Blockade in the Pre- and COVID-19 ARDS Patients

Acute respiratory distress syndrome (ARDS) accounts for a quarter of mechanically ventilated patients, while during the pandemic, it overwhelmed the capacity of intensive care units (ICUs). Lung protective ventilation (low tidal volume, positive-end expiratory pressure titrated to lung mechanics and oxygenation, permissive hypercapnia) is a non-pharmacological approach that is the gold standard of management. Among the pharmacological treatments, the use of neuromuscular blocking agents (NMBAs), although extensively studied, has not yet been well clarified. The rationale is to minimize the risk for lung damage progression, in the already-injured pulmonary parenchyma. By abolishing rigorous spontaneous efforts, NMBAs may decrease the generation of high transpulmonary pressures that could aggravate patients’ self-inflicted lung injury. Moreover, NMBAs can harmonize the patient–ventilator interaction. Recent randomized controlled trials reported contradictory results and changed the clinical practice in a bidirectional way. NMBAs have not been documented to improve long-term survival; thus, the current guidance suggests their use only in patients in whom a lung protective ventilation protocol cannot be applied, due to asynchrony or increased respiratory efforts. In the present review, we discuss the published data and additionally the clinical practice in the “war” conditions of the COVID-19 pandemic, concerning NMBA use in the management of patients with ARDS.

Muscular hydraulics drive larva-polyp morphogenesis

Development is a highly dynamic process in which organisms often experience changes in both form and behavior, which are typically coupled to each other. However, little is known about how organismal-scale behaviors such as body contractility and motility impact morphogenesis. Here, we use the cnidarian Nematostella vectensis as a developmental model to uncover a mechanistic link between organismal size, shape, and behavior. Using quantitative live imaging in a large population of developing animals, combined with molecular and biophysical experiments, we demonstrate that the muscular-hydraulic machinery that controls body movement also drives larva-polyp morphogenesis. We show that organismal size largely depends on cavity inflation through fluid uptake, whereas body shape is constrained by the organization of the muscular system. The generation of ethograms identifies different trajectories of size and shape development in sessile and motile animals, which display distinct patterns of body contractions. With a simple theoretical model, we conceptualize how pressures generated by muscular hydraulics can act as a global mechanical regulator that coordinates tissue remodeling. Altogether, our findings illustrate how organismal contractility and motility behaviors can influence morphogenesis.

Influence of the amount of skeletal muscle mass on rocuronium-induced neuromuscular block

OBJECTIVE

To evaluate the effects of skeletal muscle mass on the rocuronium-induced neuromuscular block.

DESIGN

A prospective, double-blinded, observational study SETTING: A tertiary care university hospital POPULATION: One hundred one patients aged 18-65 years who were scheduled to undergo major surgery lasting more than 1 h under general anaesthesia.

METHODS

All participants underwent body composition analysis before anaesthesia and were allocated into two groups; the muscular and non-muscular group, according to skeletal muscle mass. During anaesthesia induction, rocuronium 1.0 mg kg^-1 of total body weight was injected followed by neuromuscular monitoring using train-of-four stimulation every 15 s.

MAIN OUTCOME MEASURES

The onset time of rocuronium included the elapsed time from the rocuronium injection until 95% depression of first twitch (T1) and the time to no response to TOF stimulation. The duration was evaluated as the elapsed time from the rocuronium injection to 25% recovery of the final T1 (T_DUR25), and the time to the reappearance of T1 (T_TOF1) and T4 (T_TOF4). These pharmacologic data were compared between two groups.

RESULTS

There was no significant difference in the onset time of rocuronium between the two groups. However, T_DUR25 (min) was significantly shorter in the muscular group than in the non-muscular group (p =  0.035 and p =  0.014 in males and females, respectively). T_TOF1 and T_TOF4 were also shorter in the muscular group than in the non-muscular group.

CONCLUSIONS

Total body weight-based dosing of rocuronium might prolong the neuromuscular relaxation effect in patients with a small amount of skeletal muscle.

Pharmacodynamic of rocuronium in sickle cell patients

BACKGROUND

Sickle cell disease is the most widespread genetic disease in the world. The chronic organ damage due to this disease could lead to variability of responses to the anaesthetic drugs. We analysed the pharmacodynamics response of rocuronium to sickle cell patients.

METHODS

We observed and compared the onset time and clinical duration (time to recovery first twitch) of 0.6 mg kg^-1 of rocuronium using a TOFscan® monitor, as well as the time before the first incremental dose (time to recovery second twitch), in a group of 22 homozygous sickle cell patients and a group of 23 controls, all programmed for laparoscopic surgical procedures.

RESULTS

The onset time of rocuronium was longer in sickle cell patients [mean ± SD (extremes)], [6.3 ± 2.1 (1.8-10) min] than in the control group [2.5 ± 0.6 (1.4-3.5) min] (P < 0.01). The clinical duration was shorter in sickle cell patients [19.2 ± 7.1 (13-41) min] when compared to the control group [28.9 ± 6.9 (21-48) min] (P < 0.01). The time before the first incremental dose was shorter in the sickle cell patients group [27.7 ± 7.9 (19-49) min] compared to the control group [39.9 ± 8.7 (30-56) min] (P < 0.01).

CONCLUSION

The onset time and duration of action of rocuronium was significantly shorter in patients with sickle cell disease versus the general population.

A Narrative Overview of Current Anesthetic Drugs in Electroconvulsive Therapy

Electroconvulsive therapy (ECT) is a definitive treatment for patients with psychiatric disorders that are severe, acute, or refractory to pharmacologic therapy. Providing anesthesia for ECT is challenging, as the effect of drugs on hemodynamics, seizure duration, comfort, and recovery must be considered. We highlight and aim to review the common anesthetics used in ECT and related evidence. While drugs such as methohexital, succinylcholine, and etomidate have been used in the past, other drugs such as dexmedetomidine, ketamine, and remifentanil may provide a more balanced anesthetic with a greater safety profile in select populations. Overall, it is essential to consider the patient’s co-morbidities and associated risks when deciding on an anesthetic drug.

Method for Prediction of Efficacy of Sugammadex Administered to Recover from Rocuronium-Induced Neuromuscular Blockade in Gynecological Laparoscopic Surgery Cases

Sugammadex (SDX), a neuromuscular blocking-reversal agent, quickly reverses neuromuscular blockade induced by rocuronium (RCR). SDX dosage is set according to the state of neuromuscular blockade determined with a neuromuscular monitoring device. However, in clinical situations, such a devise is not frequently used. Here, we report construction of a method for theoretically setting SDX dose by which the optimum reverse time (RT) can be obtained for individual patients even when the device is not available. The subjects were 42 adult female patients who underwent laparoscopic surgery from 1 August 2015 to 31 March 2016, during which RCR and SDX were administered. We formulated an equation for theoretically calculating the RCR residual ratio (RR) in blood after SDX administration. Furthermore, we examined the relationship between RR and RT. Based on the results obtained, we developed a method for predicting RT using RR. We excluded 1 subject as the RT value was detected as an outlier in our analysis. Multiple regression analysis was performed using standard body weight, serum creatinine, total bilirubin, and RR as explanatory variables. The number of subjects with a prediction error of RT within ±1 min was 36 (87.8%) of 41 in multiple regression analysis. We could predict RT following SDX administration by using the RT prediction expression with RR obtained for subjects administered RCR during the surgery. Furthermore, our results suggest that the SDX dose able to achieve optimum RT may be set prior to surgery on the basis of the present methodology.

Effect of cardiopulmonary bypass on cytochrome P450 enzyme activity: implications for pharmacotherapy

For patients undergoing cardiopulmonary bypass (CPB) during cardiac surgery, there are well-documented changes in the pharmacokinetics (PK) of commonly administered drugs. Although multiple factors potentially underpin these changes, there has been scant research attention on the impact of CPB to alter the activities of cytochrome P450 (CYP) isoenzymes. PK changes during cardiac surgery with CPB have the potential to adversely affect the safety and efficacy of pharmacotherapy and increase the risk of drug-drug interactions. Clinically significant changes in drug PK during CPB are likely to be prominent for drugs where CYP metabolism is a major clearance (CL) mechanism. However, clinical data from patients undergoing CPB surgery in support of this hypothesis are lacking, leaving a significant knowledge gap. In this review, we address the effects of CPB on the release of pro-inflammatory cytokines, in surgeries with and without CPB, both pre and post initiation of surgery. We reviewed literature to explore the relationship between the release of pro-inflammatory cytokines, and the expression and activities of CYP enzymes. Through this approach, we provide new insight on the effects of CPB on the PK of drugs administered to patients in the clinical setting. Future research to address this knowledge gap will have considerable impact to assist clinicians with optimizing pharmacotherapy in this patient population.

Neuromuscular Effects of Rocuronium Bromide in Patients in Statin Therapy for at least Three Months

Statins cause skeletal muscle myopathy. However, the neuromuscular effects of non-depolarizing neuromuscular-blocking agent in patients in long-term statin therapy remain unclear. Hence, we investigated the neuromuscular effects of rocuronium and muscle injury in patients in long-term statin therapy. Eighteen statin users using statins for at least 3 months were included in the statin group and 18 non-statin users were included in the non-statin group. General anaesthesia was induced with intravenous midazolam, etomidate, sufentanil and rocuronium 0.9 mg/kg (3ED₉₅ ) for intubation. Anaesthesia was maintained with 1% propofol and remifentanil. The onset time and duration 10% T₁ and 25% T₁ of rocuronium were recorded. Blood samples were obtained before induction and 5 min., 1 hr, 2 hr, 4 hr, 12 hr and 24 hr after rocuronium administration to measure creatine kinase (CK), myoglobin and potassium. Myalgia was determined at 2 and 24 hr after surgery. There were no significant differences in the basic clinical characteristics between the two groups. The onset time of the statin group was significantly shorter than that of the non-statin group (p = 0.02), while the duration 10% T₁ and duration 25% T₁ of the statin group were significantly longer than those of the non-statin group (p = 0.006; p = 0.045). The myoglobin and CK concentrations increased after rocuronium administration as compared to baseline in both groups. CK concentration in the statin group was significantly higher than in the non-statin group just at 24 hr (p = 0.000003). However, myoglobin showed no significant difference between the two groups. The onset time of rocuronium decreases and its duration time increases in patients in long-term statin therapy.

Outcomes of abdominal surgery in patients with liver cirrhosis

Patients suffering from liver cirrhosis (LC) frequently require non-hepatic abdominal surgery, even before liver transplantation. LC is an important risk factor itself for surgery, due to the higher than average associated morbidity and mortality. This high surgical risk occurs because of the pathophysiology of liver disease itself and to the presence of contributing factors, such as coagulopathy, poor nutritional status, adaptive immune dysfunction, cirrhotic cardiomyopathy, and renal and pulmonary dysfunction, which all lead to poor outcomes. Careful evaluation of these factors and the degree of liver disease can help to reduce the development of complications both during and after abdominal surgery. In the emergency setting, with the presence of decompensated LC, alcoholic hepatitis, severe/advanced LC, and significant extrahepatic organ dysfunction conservative management is preferred. A multidisciplinary, individualized, and specialized approach can improve outcomes; preoperative optimization after risk stratification and careful management are mandatory before surgery. Laparoscopic techniques can also improve outcomes. We review the impact of LC on surgical outcome in non-hepatic abdominal surgeries required in this cirrhotic population before, during, and after surgery.

Highlights in muscle relaxants

The aim of this article is to provide an overview on neuromuscular blocking agents and a rational selection of the most appropriate agents, along with pharmacological and pharmacoeconomic considerations on neuromuscular blockers and their antagonists. Neuromuscular blocking agents are used during anesthesia to facilitate endotracheal intubation and provide surgically required paralysis. There is continuing development in the field of neuromuscular blocking agents, with new products appearing at regular intervals. All new agents come at increased costs. The proportion of anesthesia-related drug costs on a per-patient basis are small and vary from country to country, but account for no more than 12% of hospital drug budgets. However, given the large number of anesthetics performed over time, the total cost is significant. Moreover, such costs should be put into the perspective of the operating theater and patient admission costs. Appropriate selection of neuromuscular blocking agents can help not only to reduce biological costs secondary to complications, but also to make operating lists proceed smoothly and without incident. The paucity of outcome studies in relation to anesthetic drugs is not surprising given that anesthesia is used to facilitate the provision of therapy rather than being therapeutic in its own right. Accordingly, the assessment of anesthetic drugs has a different priority to therapeutic drugs. As anesthetic drugs are nontherapeutic, it is also difficult to determine the best choice of agent. However, new neuromuscular blocking agents are marketed on the basis of improvements in the frequency of side effects, safety, reliability, duration, reversibility and undesirable hemodynamic effects.

Drug absorption, distribution, metabolism and excretion considerations in critically ill adults

INTRODUCTION

All critically ill patients require medication to treat organ dysfunction. However, the pharmacokinetics of drugs used to treat these patients is complex due to frequent alterations in drug absorption, distribution, metabolism, and excretion (ADME).

AREAS COVERED

This review examines pharmacokinetic aspects of drug administration for adult intensive care unit (ICU) patients. Specifically, the authors examine the ADME changes that occur and which should be considered by clinicians when delivering drug therapy to critically ill patients.

EXPERT OPINION

Dosage pharmacokinetics determined from single-dose or limited-duration administration studies in healthy volunteers may not apply to critically ill patients. Organ dysfunction among these patients may be due to pre-existing disease or the effects of a systemic or locoregional inflammatory response precipitated by their illness. Alterations in pharmacokinetics observed among the critically ill include altered bioavailability after enteral administration, increased volume of distribution and blood-brain barrier permeability and changes in P-glycoprotein and cytochrome P450 enzyme function. However, the effect of these changes on clinically important outcomes remains uncertain and poorly studied. Future investigations should examine not only pharmacokinetic changes among the critically ill, but also whether recognition of these changes and alterations in drug therapy directed as a consequence of their observation alters patient outcomes.

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.

Neuromuscular recovery following rocuronium bromide single dose in infants

BACKGROUND

Rocuronium bromide, a steroid nondepolarizing muscle relaxant, has a rapid onset and an intermediate duration of action in infants, children and adults. However, clinical evidence shows a longer duration of recovery in small infants. The aim of this study was to investigate the influence of age on rocuronium recovery during the first year of life.

METHODS

ASA I-II infants, scheduled for elective surgery under general anaesthesia and intubation were included after ethics committee approval and parents' written consent. According to age the patients were randomly allocated to receive either 0.45 mg.kg(-1) or 0.6 mg.kg(-1) rocuronium bromide in three age-groups: (A) 0-1 month, (B) 2-4 months and (C) 5-12 months. After induction with thiopentone (5-7 mg.kg(-1)), anesthesia was maintained with isoflurane without opioids. Prior to surgery, caudal block with bupivacaine (0.125%) 1.0 ml.kg(-1) and paracetamol 25 mg.kg(-1) rectally were given for analgesia. Efficacy variables were intubation conditions 60 s after administration of muscle relaxant (T(0)) and recovery of neuromuscular blockade measured as T(1) at 10, 25, 50 and 75 % of baseline, train-of-four (TOF) of 0.7 and Recovery Index (RI). Data were characterized by summary statistics and analysis of variance.

RESULTS

A total of 61 infants with a median age range of 67 (2-364) days were included. Intubation conditions were excellent or good in all dose and age groups. T(0) in group A was reached in a range of 15-30 s, in others up to 60 s. T(1) recovery (T75) after 0.45 mg.kg(-1) was 56.4 +/- 16 (A), 62.7 +/- 32 (B) and 45.8 +/- 18 (C) min. Recovery times for of 0.6 mg.kg(-1) were 100.8 +/- 35 (A), 70.6 +/- 19 (B) and 63.4 +/- 21 (C) min, respectively. The TOF ratio (0.7) was 62.3 +/- 18 (A), 64.1 +/- 27 (B) and 43.7 +/- 12 (C) min using 0.45 mg.kg(-1) compared with 94.8 +/- 31 (A), 63.8 +/- 14 (B) and 67.5 +/- 18 (C) min with 0.6 mg.kg(-1). The differences of T75 and TOF 0.7 in A and C were significant (P </= 0.05).

CONCLUSIONS

Recovery of muscle relaxation using rocuronium bromide under isoflurane anesthesia in infants differs widely and shows great differences between age groups as well as dose regimen. A dose of 0.6 mg.kg(-1) resulted in a significantly longer duration of action in group A. The reduced dose of 0.45 mg.kg(-1) resulted in rapid and good relaxation in all infants without very long lasting effects. Reduced doses of rocuronium should be used in newborns and small infants.

The effect of cisatracurium and rocuronium on cisatracurium precurarization and the priming principle

STUDY OBJECTIVE

To demonstrate the effect of administering a precurarizing dose of cisatracurium or rocuronium on the speed of onset of cisatracurium, and to review the possible mechanisms and value of the priming principle.

DESIGN

Double-blind, randomized, controlled trial.

SETTING

Inpatient anesthesia in a university teaching hospital.

PATIENTS

90 ASA physical status I and II patients undergoing elective surgery requiring endotracheal intubation.

INTERVENTIONS

Three groups of 30 patients each were investigated. Following induction of anesthesia with fentanyl and propofol, Group 1 received cisatracurium 0.015 mg.k(-1), Group 2 received rocuronium 0.09 mg. kg(-1), and Group 3 (control) received normal saline. Six minutes after priming, Groups 1 and 2 received cisatracurium 0.135 mg. kg(-1) whereas Group 3 received cisatracurium 0.15 mg. kg(-1).

MEASUREMENTS AND MAIN RESULTS

In each group, first twitch height and the train-of-four ratios were recorded every 10 seconds after the initial priming dose. Intubation was attempted after the first twitch height became less than 15% of baseline. The decrease in the train-of-four ratios at 6 minutes was 0.97 for cisatracurium and 0.85 for rocuronium. The onset of muscle relaxation was significantly faster after priming with cisatracurium and rocuronium (71.7 +/- 21.3 and 65 +/- 19.8 sec, respectively) compared with control (148.7 +/- 43.1 sec). Females receiving both muscle relaxants had a faster onset of paralysis than did males (65.9 +/- 20.6 vs. 79.2 +/- 20.6 and 55 +/- 14.5 vs. 71.7 +/- 20.4 sec). Intubation conditions were either excellent or satisfactory in all patients.

CONCLUSIONS

Six minutes after precurarization, there is no significant difference between rocuronium and cisatracurium when used as priming drugs. An even faster onset time with both drugs was demonstrated in females. The use of priming doses of 25% to 30% of ED(95) may cause symptomatic muscle weakness. The mechanisms of the priming principle are discussed.

Target-controlled infusion of rocuronium in infants, children, and adults: a comparison of the pharmacokinetic and pharmacodynamic relationship

Target-controlled infusion (TCI) of rocuronium can be used to maintain a stable blood concentration (Cp). At steady-state, the pharmacokinetics (PK) are compensated for by TCI, and a stable effect can be observed. The theoretical Cp may represent effect-site concentration (EC). We used the EC-effect relationship to study pharmacodynamics (PD) in infants, children, and adults. After giving their written, informed consent, 14 infants, 23 children, and 21 adults scheduled for elective surgical procedures received 3 to 6 ascending Cp targets of TCI rocuronium according to PD data. Just before each increase of TCI, venous blood samples were taken to measure Cp. Neuromuscular block was evaluated acceleromyographically. Individual effect data and measured Cp were fitted to the Hill equation. Maximum block during TCI targets-1000, 1300, and 1600 ng/mL-was smaller in children in comparison with infants and adults. The concentration in the effect compartment associated with a 50% drug effect (EC(50)) was significantly smaller in infants (mean [SD]) (652 [215] ng/mL) than in adults (954 [276] ng/mL) and was the largest in children (1200 [295] ng/mL). Calculated mean EC(90) values were 1705, 2230, and 2035 ng/mL, respectively, in infants, children, and adults. TCI rocuronium established steady-state PK/PD at different TCI targets and allowed us to define PK/PD relationships in a standardized way. Steady-state TCI rocuronium revealed the most potency of rocuronium in infants and the least in children.

IMPLICATIONS

Target-controlled infusion (TCI) of rocuronium in infants, children, and adults was used to analyze the pharmacokinetic/pharmacodynamic relationship. Steady-state TCI rocuronium revealed the most potency of rocuronium in infants and the least in children.

Cortical processing of noxious somatosensory stimuli in the persistent vegetative state

The persistent vegetative state (PVS) is a devastating medical condition characterized by preserved wakefulness contrasting with absent voluntary interaction with the environment. We used positron emission tomography to assess the central processing of noxious somatosensory stimuli in the PVS. Changes in regional cerebral blood flow were measured during high-intensity electrical stimulation of the median nerve compared with rest in 15 nonsedated patients and in 15 healthy controls. Evoked potentials were recorded simultaneously. The stimuli were experienced as highly unpleasant to painful in controls. Brain glucose metabolism was also studied with [(18)F]fluorodeoxyglucose in resting conditions. In PVS patients, overall cerebral metabolism was 40% of normal values. Nevertheless, noxious somatosensory stimulation-activated midbrain, contralateral thalamus, and primary somatosensory cortex in each and every PVS patient, even in the absence of detectable cortical evoked potentials. Secondary somatosensory, bilateral insular, posterior parietal, and anterior cingulate cortices did not show activation in any patient. Moreover, in PVS patients, the activated primary somatosensory cortex was functionally disconnected from secondary somatosensory, bilateral posterior parietal, premotor, polysensory superior temporal, and prefrontal cortices. In conclusion, somatosensory stimulation of PVS patients, at intensities that elicited pain in controls, resulted in increased neuronal activity in primary somatosensory cortex, even if resting brain metabolism was severely impaired. However, this activation of primary cortex seems to be isolated and dissociated from higher-order associative cortices.

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.

Emergency department use of neuromuscular blocking agents in children

There is no ideal neuromuscular blocking agent with a rapid onset and ultra-short duration of action with a good safety profile in children. Rocuronium, vecuronium, rapacuronium, and succinylcholine are currently the neuromuscular blocking agents most suitable for children who require RSI in ED settings. Succinylcholine is the only agent with rapid onset and ultra-short duration of action; however, it has many potential side effects, of which some (albeit rare) may be fatal. In select situations, some emergency physicians may decide that the benefits of succinylcholine outweigh the risks; however, others may choose a nondepolarizing agent as their drug of choice for RSI. Rocuronium has an excellent safety profile and a rapid onset of action similar to succinylcholine. Despite a longer duration of action, rocuronium is the preferred agent for RSI in children by many physicians. For EDs that do not have access to rocuronium, vecuronium is frequently the agent of choice for RSI in children. Despite its longer onset of action and recovery, its side effects are minimal when compared to succinylcholine. If further studies confirm the safety profile of rapacuronium, its rapid onset and short duration of action will likely make it the neuromuscular blocking agent of choice for RSI.

Urinary, biliary and faecal excretion of rocuronium in humans

The excretion of rocuronium and its potential metabolites was studied in 38 anaesthetized patients, ASA I-III and 21-69 yr old. Rocuronium bromide was administered as an i.v. bolus dose of 0.3 or 0.9 mg kg-1. In Part A of the study, the excretion into urine and bile, and the liver content were studied. Plasma kinetics (n = 19) were similar to those reported previously. Urinary recovery within 48 h after administration was 26 (8)% (mean (SD)) (n = 8) of the dose. In bile obtained from T-drains, the recovery within 48 h was 7 (6)% (n = 11). The rocuronium concentration in bile declined bi-exponentially, with half-lives of 2.3 (0.7) and 16 (11) h respectively (n = 6). In three patients from whom stoma fluid was collected, the amount of rocuronium recovered ranged from 0.04 to 12.0% of the dose. In liver tissue obtained from four patients undergoing hemihepatectomy, the estimated amount of rocuronium at 2-5 h after administration ranged between 6.3 and 13.2% (n = 4). In the second part of the study (Part B), urine and faeces were collected over 4-8 days and the recovery was 27 (13)% and 31 (23)% of the dose respectively (n = 10). In most samples, irrespective of the type of biological material, only small amounts of the metabolite 17-desacetyl-rocuronium was found. The results demonstrate that rocuronium is taken up by the liver and excreted into bile in high concentrations. The faecal and urinary excretion of unchanged rocuronium are the major routes of rocuronium elimination.