PHARMACOKINETICS AND PHARMACODYNAMICS OF STEROIDAL MUSCLE RELAXANTS

Association between postoperative shoulder pain and left-side laparoscopic urologic surgery: a single-center retrospective cohort study

PURPOSE

Postoperative shoulder pain is a common problem after laparoscopic surgery. This study aimed to investigate the association between operative side and postoperative shoulder pain following urologic laparoscopic surgery performed in the lateral recumbent position.

METHODS

This was a retrospective cohort study conducted at a single tertiary care center. A total of 506 patients who underwent urologic laparoscopic surgery (including adrenalectomy, radical nephrectomy, partial nephrectomy, and pyeloplasty) between January 2010 and December 2019 were included. Patients who underwent total nephroureterectomy or resection of other organs were excluded. The primary outcome was the incidence of postoperative shoulder pain. A multivariable logistic regression analysis investigated the association between the operative side and postoperative shoulder pain.

RESULTS

Among the 506 included patients, there were an equal number of surgeries on the left and right sides. Eighty-eight patients had postoperative shoulder pain. The incidence of postoperative shoulder pain in the left-side group was significantly higher than that in the right-side group (21.3% [54/253] versus 13.4% [34/253], crude odds ratio = 1.75, 95% confidence interval [CI] 1.07-2.89). After adjustment for potential confounders (age, sex, body mass index, operation duration, operative technique, epidural block, peripheral nerve block, American Society of Anesthesiologists physical status classification, and intraoperative rocuronium dose), the left operative side was found to be associated with postoperative shoulder pain (adjusted odds ratio = 1.89, 95% CI 1.15-3.09).

CONCLUSION

The left operative side is associated with an increased incidence of postoperative shoulder pain after urologic laparoscopic surgery performed in the lateral recumbent position.

Physicochemical properties of neuromuscular blocking agents and their impact on the pharmacokinetic-pharmacodynamic relationship

BACKGROUND

Among the factors influencing the onset of action of neuromuscular blocking agents (NMBA), the potency (EC50) and the rate of equilibration between blood and the effect compartment (k(e0)) have been highlighted. Although these descriptors are intrinsically influenced by the physicochemical characteristics of the drug, the impact of lipid solubility, molecular weight and protein binding on pharmacokinetic-pharmacodynamic (PK-PD) descriptors has not been established for most NMBA.

METHODS

The octanol/phosphate buffer distribution coefficients (logD) of various NMBA (vecuronium, rocuronium, mivacurium isomers (cis-cis, cis-trans and trans-trans), doxacurium, cisatracurium, atracurium, succinylcholine) were determined. The free fraction for each drug was measured using an ultrafiltration technique. PK-PD descriptors were obtained from selected clinical studies. Correlations between physicochemical parameters (including molecular weight) and PK-PD descriptors were assessed by linear or multiple linear regression.

RESULTS

A wide range of log D (-4.15 for succinylcholine to 0.75 for vecuronium) and free fraction (from 31% for vecuronium to 80% for succinylcholine) is observed for NMBA. Molecular weight combined with either lipid solubility (r2=0.70; P=0.001) or free fraction (r2=0.84; P<0.001) were highly correlated with potency, while for k(e0) a greater degree of correlation was obtained when both lipid solubility and free fraction (r2=0.74; P=0.002) were included.

CONCLUSIONS

The basic characteristics of NMBAs, namely, molecular weight, lipid solubility and protein binding, are strongly associated with the kinetics of the drug response.

Pharmacokinetic studies of neuromuscular blocking agents: good clinical research practice (GCRP)

In September 1997, an international consensus conference on standardization of studies of neuromuscular blocking agents was held in Copenhagen, Denmark. Based on the conference, a set of guidelines for good clinical research practice (GCRP) in pharmacokinetic studies of neuromuscular blocking agents is presented. Guidelines include: design of the study; relevant patient groups to investigate; test drug administration, sampling and analysis; pharmacokinetic analysis; pharmacokinetic/pharmacodynamic modeling; population pharmacokinetics; statistics; and presentation of pharmacokinetic data. The guidelines are intended to aid those working in this research area; it is hoped that they will assist researchers, editors of scientific papers, and pharmaceutical companies in improving the quality of pharmacokinetic studies.

[The use of curare-like agents in resuscitation]

OBJECTIVE

To analyse current data on use of neuromuscular blocking agents (NBA) in the intensive therapy unit (ITU) patients and to propose practice guidelines.

DATA SOURCES

We did a Medline search of French and English language articles on NBA administration in ITU patients from 1960 to 1998. Data were also selected from our own collection of articles and books.

STUDY SELECTION

Original articles, clinical cases, letters to the editor and review articles were considered.

DATA EXTRACTION

Data on pharmacology of NBA in the ITU patient were extracted, as well as data on administration patterns and cost.

DATA SYNTHESIS

The indications for myorelaxation in ITU patients include either short term use, as in anaesthesia, or long term administration for facilitation of mechanical ventilation, control of increased intracranial pressure, status epilepticus, tetanus and oxygen demand in case of muscular hyperactivity, diagnostic and therapeutic procedures facilitation. A beneficial effect of NBA on the prognosis of the disease for which these agents have been used is not yet proven. Suxamethonium, because for its short onset time and duration of action, is the agent of choice for endotracheal intubation if myorelaxation is required. Among the benzylisoquinolines, atracurium and besilate of cisatracurium are convenient agents in ITU patients, whereas mivacurium is of no special interest. Among the aminosteroids, pancuronium and vecuronium are the most often used agents in the ITU. Rocuronium has not yet been extensively assessed. Myorelaxants carry risks for morbidity and mortality. The difficulty to assess the neurological status and the level of sedation is a recognised adverse effect. An accidental disconnection from the circuit and the resulting asphyxia is nowadays recognised without delay by the ventilator. NBAs increase the rate of bronchopulmonary infections. Cardiovascular complications include extreme bradycardia or sinus arrest following vecuronium administration, and cardiac arrest after suxamethonium injection mainly in burned or traumatised patients. Conversely to anaesthesia, NBAs do not carry a significant risk for anaphylactic or anaphylactoid complications in the ITU. Tachyphylaxis occurs mainly in burns and other pathologies modifying acetylcholine receptors. Neuromuscular complications include myopathy from steroids, postparalytic syndrome, deconditioning syndrome and intensive care polyneuropathy. Prolonged curarisation after discontinuation of NBA administration has a multifactorial origin and must be differentiated from neuromuscular complications. For prolonged neuromuscular blockade, pancuronium, vecuronium and atracurium are the agents of choice. The association with an adequate sedation is essential. Assessment of depth of neuromuscular blockade is not based on clinical symptoms but on train-of-four (TOF) twitch monitoring. A convenient basic relaxation is usually obtained with the suppression of the two last responses to TOF.

CONCLUSION

The use of NBA in ITU patient should result from a rational decision making procedure, the blockade titrated with a TOF monitor and maintained as superficially and shortly as possible.

Rocuronium priming of atracurium-induced neuromuscular blockade: the use of short priming intervals

STUDY OBJECTIVE

To evaluate the effects of priming doses of rocuronium on the duration of priming interval and on the outcome of priming sequence using rocuronium-atracurium combination.

DESIGN

Three phase, randomized, controlled study.

SETTING

Inpatient anesthesia in a university hospital.

PATIENTS

144 ASA physical status I and II patients, 19 to 57 years of age, weighing 50 to 90 kg, and undergoing low-risk elective surgery.

INTERVENTIONS

Phase I, two equal groups (n = 12) of adult patients anesthetized with propofol, fentanyl, and nitrous oxide (N2O), received a priming dose of rocuronium 0.1 mg/kg or vecuronium 0.015 mg/kg. Phase II included six equal groups (n = 12): Groups 1, 2, and 3 received a priming dose of rocuronium 0.1 mg/kg and atracurium 0.42 mg/kg for intubation. The priming intervals were, respectively, 1, 1.5, or 2 minutes in Groups 1, 2, and 3. Groups 4, 5, and 6 received, respectively, a bolus dose of rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 mg/kg. Intubation was performed at maximum block. Phase III included four equal groups (n = 12). A priming dose of rocuronium 0.1 mg/kg (Group 1) or a placebo (Groups 2, 3, and 4) was given to awake patients. Anesthesia was induced during the one-minute priming interval. Intubating doses of atracurium 0.42 mg/kg, rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 mg/kg were given to Groups 1, 2, 3, and 4, respectively. Intubation was attempted 1 minute after intubating doses were administered.

MEASUREMENTS AND MAIN RESULTS

Adductor pollicis response to train-of-four stimulation was recorded mechanically in Phases I and II only. The priming interval after rocuronium 0.1 mg/kg was in the range of 1 to 2 minutes. Priming doses of rocuronium resulted in significant acceleration in the onset time of intubating doses of atracurium, irrespective of the duration of the priming interval. The onset times [mean (SD)] following rocuronium-atracurium sequence in Groups 1, 2, and 3 were, respectively, 67 (17), 73 (14), and 66 (18) seconds and were comparable with the onset of bolus doses of rocuronium and succinylcholine. In Phase II, good to excellent intubating conditions were obtained in 41% to 58% of patients included in Groups 1 through 5. Excellent to good intubating conditions were obtained in all patients (100%) who received succinylcholine. In Phase III, good to excellent intubating conditions were obtained in 91% of patients who received recuronium-atracurium sequence. Symptoms of muscle weakness were not reported.

CONCLUSIONS

Priming doses of recuroniums 0.1 mg/kg reduce the priming interval to 1 minute, allow early induction of anesthesia, eliminate patient discomfort, and accelerate the onset time of altracurium with intubating conditions comparable with succinylcholine and rocuronium.

Comparison of the infusion requirements and recovery profiles of vecuronium and cisatracurium 51W89 in intensive care unit patients

The selection and administration of neuromuscular blocking (NMB) drugs in intensive care unit (ICU) patients remain controversial. We compared the dose-response and recovery pharmacodynamics of a new intermediate-acting NMB drug, cisatracurium besylate, to the intermediate-acting NMB drug, vecuronium (VEC), in a prospective, randomized, double-blind, multicenter study in critically ill adults. After informed consent, 58 mechanically ventilated ICU patients from five medical centers were randomized to receive either cisatracurium or VEC. Fifty-four of the 58 patients received NMB drugs before entering this study but demonstrated at least partial recovery (> or = one twitch) in the train-of-four (TOF) response before initiation of the NMB study drug. NMB drug infusion was titrated by peripheral nerve stimulation to maintain at least one twitch in the TOF response. NMB drugs were infused for 1-5 days. After discontinuation of NMB drug infusion, recovery of neuromuscular transmission was monitored with an accelerometer. NMB drug infusion for 28 cisatracurium patients averaged 2.6 +/- 0.2 (mean +/- SEM) micrograms.kg-1.min-1 with a mean duration of 80 +/- 7 h. After discontinuing cisatracurium administration, recovery to 70% TOF ratio averaged 68 +/- 13 min. The mean infusion rate for 30 VEC patients was 0.9 +/- 0.1 micrograms.kg-1.min-1 with a mean duration of 66 +/- 12 h. Neuromuscular recovery after VEC averaged 387 +/- 163 min, which was significantly longer (P = 0.02) than that after cisatracurium. Prolonged recovery of neuromuscular function after discontinuation of NMB drug infusion (identified by the primary investigator at each medical center) was reported in two cisatracurium patients and 13 VEC patients (P = 0.002), and occurred despite the routine use of neuromuscular twitch monitoring. Seven VEC and one cisatracurium patients died during the infusion of study drug or within 48 h after discontinuation of the NMB drug infusion. In summary, we found recovery of neuromuscular function after discontinuation of NMB drug infusion in ICU patients is significantly faster with cisatracurium than with VEC. In addition, routine neuromuscular monitoring was not sufficient to eliminate prolonged recovery and myopathy in ICU patients.