Quantitative determination of atracurium in human plasma using high-performance liquid chromatography.

The authors have established a new method for extraction and determination of atracurium in human plasma that employs a reversed phase high-performance liquid chromatography (HPLC). This method made use of a fluorescent spectrophotometer at an excitation wavelength of 240 nm and an emission wavelength of 310 nm. The mobile phase was made of a phosphate buffer, distilled water and acetonitrile (20V : 30V : 50V). The analytical column used was a Little Champ C(18). In a Bond Elute C(18) extraction column, which had been prewashed with a phosphate buffer and a 50% methanol solution, atracurium was extracted from acidified plasma samples using a mixture of methanol and phosphate buffer. A standard curve was prepared by the internal standard method using metocurine. A high linear correlation between atracurium concentration and the ratio of the atracurium peak height to the metocurine peak height was observed (r = 0.9994). The lowest threshold for detection of atracurium was 15 ng/ml. When the plasma concentrations of atracurium were determined in 2 clinical cases, t(1/2Alpha) was 2.10 and 1.73 min and t(1/2Beta) was 15.57 and 21.57 min, respectively. These results indicate that this method of extraction and determination is appropriate for studying the pharmacokinetics of atracurium because it allows a high reproducibility, and provides an extremely accurate, simple and quick analysis.

Pharmacokinetics and pharmacodynamics of atracurium during isoflurane anesthesia in normal and anephric patients.

We compared the pharmacokinetics and pharmacodynamics of atracurium in eight normal and eight anephric patients during isoflurane anesthesia. Plasma concentrations were measured by high performance liquid chromatography after a single injection of 0.5 mg/kg, and neuromuscular effects were evaluated by the single twitch method. With regard to pharmacokinetic or pharmacodynamic parameters, we found no statistically significant differences between normal and anephric patients. We conclude that during isoflurane anesthesia, anephric patients distribute and eliminate atracurium much as normal patients do.

Anesthetic considerations in the surgical repair of intracranial aneurysms: preanesthetic evaluation.

A preoperative evaluation for anesthesia is useful to: 1. Assess the patient's physical status and evaluate anesthetic risk 2. Judge the cardiovascular and general medical status with particular regard to hypotensive techniques 3. Estimate preoperative pulmonary reserve 4. Order appropriate premedications 5. Become aware of anatomical features relevant to the anesthetic techniques If the anesthetist has made a careful preoperative review, the patient's status is well understood and the likelihood of any complication related to anesthesia during surgery is greatly diminished.

Combination of pancuronium and metocurine: neuromuscular and hemodynamic advantages over pancuronium alone.

Combination of pancuronium and metocurine or pancuronium and d-tubocurarine produces potentiation of neuromuscular blocking effects such that administration of relatively small doses of these drugs can yield clinically effective neuromuscular blockade. The clinical characteristics of the block produced in A.S.A. class I-II patients during N2O-narcotic-thiopental anesthesia by the pancuronium-metocurine combination at the calculated ED95 (N = 8) and at twice the ED95 (N = 9) were compared with the block produced by pancuronium alone at its ED95 (N = 20) and at twice the ED95 (N = 6). Onset time (from drug injection to 95% twitch suppression) and the maximum twitch depression achieved were comparable between corresponding groups, but the 25% recovery time (from drug injection to 25% recovery of twitch height) was significantly shorter in the groups that received the pancuronium-metocurine combination. Furthermore, at twice the ED95, heart rate increased significantly more in the pancuronium group than in the pancuronium-metocurine combination group. Mean systemic blood pressure did not change significantly in either group. We conclude that patients given a combination of pancuronium and metocurine in large doses experience less hemodynamic change and more rapid recovery of neuromuscular function than do patients given equivalent doses of pancuronium alone.