The pharmacokinetics and pharmacodynamics of cisatracurium in critically ill patients with severe sepsis

Pharmacokinetics and pharmacodynamics studies of a loading dose of cisatracurium in critically ill patients with respiratory failure

Background

Previous studies reported a slow neuromuscular response with the currently recommended dose of cisatracurium in critically ill patients. Pharmacokinetic and pharmacodynamic studies of cisatracurium in critically ill patients are still limited. To our knowledge, this is the first study performed to better understand the pharmacokinetics (PKs) and pharmacodynamics (PDs) of a loading dose of cisatracurium and to identify factors that affect PK and PD changes in critically ill patients.

Methods

A prospective PKs and PDs study was designed. Arterial blood samples of 10 critically ill patients with respiratory failure were collected after administering a loading dose of 0.2 mg/kg of cisatracurium. Plasma cisatracurium and laudanosine concentrations were determined using liquid chromatography-tandem mass spectrometry. The achievement of the desired pharmacodynamic response was evaluated by both 1) clinical assessment and 2) train-of-four monitoring. The PK/PD indices were analyzed for their correlation with patient’characteristics and other factors.

Results

The one-compartment model best described the plasma pharmacokinetic parameters of cisatracurium. The volume of distribution at steady state and total clearance were 0.11 ± 0.04 L/kg and 2.74 ± 0.87 ml/minute/kg, respectively. The mean time to train-of-four 0/4 was 6 ± 3.86 minutes. A time to the desired pharmacodynamic response of less than 5 minutes was found in 10% of the patients. A positive correlation was found between cisatracurium concentration and albumin levels and between pharmacokinetics data and patient factors [partial pressure of carbon dioxide and respiratory alkalosis].

Conclusion

The currently recommended loading dose of cisatracurium might not lead to the desired pharmacodynamic response in critically ill patients with respiratory failure.

Trial registration

ClinicalTrials.gov, NCT03337373. Registered on 9 November 2017

Abnormal cisatracurium pharmacodynamics and pharmacokinetics among patients with severe aortic regurgitation during anesthetic induction

Background

This study was designed to examine whether severe aortic regurgitation will affect the pharmacodynamics (PD) and pharmacokinetics (PK) of cisatracurium during anesthetic induction.

Methods

A total of 32 patients were divided into two groups: the AR group (n = 16) and the control group (n = 16). Arterial blood samples were drawn before and at 1, 2, 4, 6, 8, 10, 16 and 20 min after intravenous injection of 0.15 mg/kg cisatracurium. TOF tests were applied to determine the onset time of maximal muscle relaxation. The concentration of cisatracurium in plasma was determined by high-performance liquid chromatography.

Results

The onset time to maximal neuromuscular block was prolonged from 2.07 ± 0.08 min to 4.03 ± 0.14 min, which indicated that the PD responses to cisatracurium were significantly delayed in the AR group (P < 0.05) compared to the control group.

A conventional two-compartment PK model showed a higher plasma concentration of cisatracurium among the AR group with markedly reduced intercompartment transfer rate (K₁₂ = 0.19 ± 0.02 and K₂₁ = 0.11 ± 0.01 in the AR group vs. K₁₂₌0.26 ± 0.01 and K₂₁ = 0.19 ± 0.01 in the control group, P < 0.01) compared to the control group.

Conclusion

Backward blood flow during diastole in severe AR impaired distribution of cisatracurium from the central compartment to the peripheral compartment, which accounted for the lagged PD responses.

Findings in this study underlie the importance of muscular blockade monitoring among patients with severe aortic regurgitation during anesthetic induction.

Registration

Name of the registry: Abnormal Cisatracurium Pharmacodynamics and Pharmacokinetics among Patients with Severe Aortic Regurgitation during Anesthetic Induction. Trial registration number: ChiCTR1800019654. Date of registration: November 20th 2018.

Predictors of Cisatracurium Continuous Infusion Dose in Acute Respiratory Distress Syndrome

Neuromuscular blockade (NMB) with cisatracurium may improve outcomes in the acute respiratory distress syndrome (ARDS) population; however, optimal dosing strategy remains unknown. Factors affecting pharmacokinetics and pharmacodynamics of cisatracurium may impact the dose required to achieve adequate train-of-four (TOF) response. The aims of this study were to determine cisatracurium dose requirements in a critically ill ARDS population and to identify clinical factors that affect dosing. This was a single-center, retrospective cohort study of medical intensive care patients who received cisatracurium infusion for treatment of ARDS. "Stable dose" was defined as the infusion rate producing 2 consecutive TOFs of 1/4 to 2/4. Factors examined for association with dose were temperature, pH, age, and the presence of acute kidney injury (AKI). The analysis included 39 patients. The median stable dose of cisatracurium was 2.8 (2.0, 3.1) μg/kg/min. Multivariable linear regression model for weight-normalized dose identified AKI as a factor independently associated with steady-state dose requirements (% change -31.4, 95% confidence interval [CI]: -51.9, -2.3). Our study provides information on cisatracurium doses required in patients with ARDS to reduce time required to reach goal TOF. Further studies are needed to determine effect of AKI on cisatracurium dose requirements and clinical outcomes.

Altered pharmacodynamics and pharmacokinetics of cisatracurium in patients with severe mitral valve regurgitation during anaesthetic induction period

AIM

The aim of the current study was to characterize the pharmacokinetics (PK) and pharmacodynamics (PD) of cisatracurium in patients with severe mitral valve regurgitation (MR) during the anaesthetic induction period.

METHODS

Thirty patients in the clinical trial were divided into two groups: the MR group (n = 15) and the control group (n = 15). Arterial blood samples were obtained before (time 0) and at 1, 2, 4, 6, 8, 10, 15 and 20 min after intravenous injection of 0.15 mg kg^-1 cisatracurium. The degree of neuromuscular block was measured by train of four (TOF) testing. The concentration of cisatracurium in the plasma was determined by high-performance liquid chromatography. A conventional two-compartment model and integrated PK/PD model were applied to PK and PD data analysis, respectively.

RESULTS

The results of PK model fitting demonstrated that severe MR reduced the distribution rate of cisatracurium from the central to peripheral compartment, resulting in a higher concentration of the drug in the plasma. The time to the maximal neuromuscular blocking effect of cisatracurium was delayed in the MR group (2.08 min in the control group vs. 4.12 min in the MR group). The PK/PD model indicated that the distribution rate of cisatracurium from the blood to the effect compartment was decreased in the MR group.

CONCLUSIONS

The present study suggested that the PK and PD of cisatracurium were significantly altered in patients with severe MR. The study has the potential to improve the safety of anaesthetic induction in patients with severe MR through accurate prediction of the PD responses of cisatracurium using the established PK/PD model.

Pharmacodynamic changes with vecuronium in sepsis are associated with expression of α7- and γ-nicotinic acetylcholine receptor in an experimental rat model of neuromyopathy

BACKGROUND

Resistance to non-depolarizing neuromuscular blocking agents induced by sepsis is associated with the qualitative change in the nicotinic acetylcholine receptor (nAChR). This study aims to investigate the effects of sepsis on the neuromuscular block properties of vecuronium in relation to the expression of fetal and neuronal α7 type nAChR.

METHODS

Male Sprague-Dawley rats were randomly divided into sham and sepsis groups. Sepsis was induced by caecal ligation and puncture (CLP). The rats were injected i.v. with ulinastatin or normal saline on Day 10. Neuromuscular block properties of vecuronium were evaluated and neuromuscular function was assessed by electromyography on Days 1, 3, 7, and 14 after CLP. Expression of fetal and neuronal type α7-nAChR on the tibialis anterior muscle was assessed using immunohistochemistry and western blot. The mRNA encoding for γ- and α7 subunits was evaluated by real-time polymerase chain reaction.

RESULTS

The half maximal inhibitory response of vecuronium in the sepsis group significantly increased, peaked on Day 7, and then declined on Day 14 (P<0.05). The neuromuscular function decreased with increasing postoperation time in the sepsis group (P<0.05). Sepsis significantly increased the expression of γ- and α7-nAchR along with expression of γ- and α7 subunits mRNA, peaked on Day 7, and declined on Day 14 (P<0.05). Ulinastatin suppressed the expression of receptor protein and mRNA encoding for γ- and α7 subunits (P<0.05).

CONCLUSIONS

Pharmacodynamic changes with vecuronium seem to be associated with the expression of γ- and α7-nAChR in the skeletal muscle. Ulinastatin can improve this effect by inhibiting the expression of these receptors.