Cisatracurium-induced neuromuscular blockade in anticonvulsant treated neurosurgical patients

Resistance to cisatracurium in a patient with MELAS syndrome

There are conflicting reports on the response of mitochondrial myopathy patients to the neuromuscular blocking drugs, showing either normal response or marked sensitivity. We present a patient with MELAS syndrome who underwent Nissen fundoplication and gastrojejunostomy. Marked resistance to the nondepolarizing muscle relaxant, cisatracurium was observed. The anesthesia management, as well as the various causes of resistance to cisatracurium in this patient are discussed.

Medication use in the elderly patient: focus on the perioperative/perianesthesia setting

As the population ages, the use of multiple medications also increases. Polypharmacy (taking multiple drugs at a time) presents concerns to the perianesthesia nurse who is caring for the geriatric patient. The pharmacokinetics and pharmacodynamics of drugs are often altered in older adult patients. Adverse drug reactions and drug interactions occur more often in geriatric patients than in younger patients. For these reasons, the benefits and risks of multiple medications and the administration of certain types of drugs must be carefully considered in the elderly patient. The selection of any medication should be individually based on the benefits and risks. Adverse drug reactions play a significant role in hospitalization for the general population, and the elderly are more susceptible to these. These drug reactions often contribute to significant morbidity as well as mortality. Medications need to be considered carefully in the older adult patient, but perhaps more so in the perioperative/perianesthesia period. Drug interactions are diverse. The type of anesthesia may influence the patient's outcome, depending on the medications the patient is currently taking. The patient's response to the stress of surgery is also affected by individual medical conditions as well as medications the patient is currently receiving Polypharmacy, inappropriate medications, adverse drug reactions, drug-disease issues, and drug interactions in the geriatric population are concerns in the perioperative/perianesthesia setting.

Cisatracurium-Induced Neuromuscular Blockade Is Affected by Chronic Phenytoin or Carbamazepine Treatment in Neurosurgical Patients

The effect of chronic anticonvulsant therapy (CAT) on the maintenance and recovery profiles of cisatracurium-induced neuromuscular blockade has not been adequately studied. In this study, we compared the pharmacokinetics and pharmacodynamics of cisatracurium after a prolonged infusion in patients with or without CAT. Thirty patients undergoing intracranial surgery were enrolled in the study: 15 patients under CAT (carbamazepine and phenytoin, Group A) and 15 controls receiving no anticonvulsant therapy (Group C). Anesthesia was standardized and both groups received a bolus of cisatracurium followed by an infusion to maintain a 95% twitch depression. A steady-state was obtained and the infusion was kept constant for 2 additional hours. Neuromuscular blockade was then allowed to spontaneously recover. Blood samples were taken for measurement of cisatracurium plasma concentration during the steady-state period (Cp(ss)95) and at various times during recovery. Demographic and intraoperative data were similar. CAT resulted in faster 25% and 75% recovery of the first twitch. The rate of infusion of cisatracurium needed to maintain a 95% twitch depression at steady-state was 44% faster in Group A (P < 0.001). The clearance of cisatracurium was significantly faster in Group A when compared with Group C (7.12 +/- 1.87 versus 5.72 +/- 0.70 L . kg(-1) . min(-1), P = 0.01). The Cp(ss)95 was also significantly larger in Group A (191 +/- 45 versus 159 +/- 36 ng/mL, P = 0.04). In addition, patients receiving CAT had a 20% increase in the clearance of cisatracurium that, in turn, resulted in a faster recovery of neuromuscular blockade after an infusion of the drug. Also, patients under CAT had a 20% increase in their Cp(ss)95, indicating an increased resistance to the effect of cisatracurium.

Muscle relaxants in neurosurgical anaesthesia: a critical appraisal

The use of muscle relaxants, considered until recently as common practice in current neurosurgical anaesthesia protocols, becomes increasingly more questionable today. The reasons rely on the evolution of neurosurgery including the advent of new surgical techniques, the evolution of anaesthesia having the benefit of new drugs and devices, and the rationale for using muscle relaxants balanced against their potential side-effects and possible pharmacodynamic alterations in neurosurgical patients.