Comparison of propofol with isoflurane for maintenance of anesthesia in patients with chronic obstructive pulmonary disease: use of pulmonary mechanics, peak flow rates, and blood gases.

Patients with chronic obstructive pulmonary disease (COPD) are usually anesthetized with an inhalation agent. After Institutional Review Board approval, informed consent was obtained from 60 patients with moderate to severe COPD according to a preoperative severity scoring system, which took into account history and objective findings. By using objective criteria, such patients were randomly assigned to receive propofol (group I) or isoflurane (group II) as primary maintenance agents. Preoperative and postoperative arterial blood gases, peak expiratory flow rates (PEFR), and chest X-rays were compared. Total dynamic compliance (CDYN) and V1 (% volume exhaled in first second) were measured using Pitot tube sidestream spirometry. A 1,000-mL super-syringe was used to measure total static compliance (CST). Measurements were recorded postintubation, midanesthesia, and pre-extubation. All patients received fentanyl, lidocaine, and propofol, 1.5 to 2.0 mg/kg, for induction. Succinylcholine, 1-1.5 mg/kg, was administered to facilitate intubation. Maintenance was with N2O-O2, vecuronium, and either propofol (n = 30) or isoflurane (n = 30). Both groups showed decreases in postoperative PaO2, SaO2, and PEFR (p < 0.05), but there were no differences between groups (p > 0.05). There were no significant chest X-ray differences. There were no differences between groups with respect to intraoperative pulmonary mechanics (p > 0.05). The only difference between groups was an increase in postoperative PaCO2 in group I and a decrease in group II (p < 0.05). Use of Pitot tube sidestream spirometry is a practical and noninvasive technique for monitoring pulmonary mechanics during anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Which drug prevents tachycardia and hypertension associated with tracheal intubation: lidocaine, fentanyl, or esmolol?

Eighty patients, ASA physical status II-IV, scheduled for noncardiac surgery, were randomly assigned in a double-blind, placebo-controlled manner to receive a preintubation dose of either placebo, 200 mg lidocaine, 200 micrograms fentanyl, or 150 mg esmolol. Induction of anesthesia was accomplished with 4-6 mg/kg thiopental IV followed immediately by the study drug; 1-1.5 mg/kg succinylcholine was given at minute 1. Laryngoscopy and intubation were performed at minute 2 with anesthesia thereafter maintained with 1 MAC (+/- 10%) isoflurane in 60% nitrous oxide in oxygen at a 5 L/min flow for 10 min. Heart rate was recorded every 15 s and blood pressure every minute from induction until 10 min after intubation. Maximum percent increases in heart rate (mean +/- SE) during and after intubation were similar in the placebo (44% +/- 6%), lidocaine (51% +/- 10%), and fentanyl (37% +/- 5%) groups, but lower in the esmolol (18% +/- 5%) group (P less than 0.05). Maximum systolic blood pressure percent increases were lower in the lidocaine (20% +/- 6%), fentanyl (12% +/- 3%), and esmolol (19% +/- 4%) groups than in the placebo (36% +/- 5%) group (P less than 0.05), but not different from each other (P greater than 0.05). Only esmolol provided consistent and reliable protection against increases in both heart rate and systolic blood pressure accompanying laryngoscopy and intubation.

Can esmolol manage surgically-induced tachycardia? Bolus esmolol treatment of intra-operative tachycardia due to surgical stimulation.

A double-blind, randomised study was conducted to examine the efficacy of a single bolus dose of esmolol in treating surgically-induced tachycardia. Anaesthetic technique was identical in all patients, and consisted of premedication with midazolam and glycopyrronium, induction with thiopentone followed by suxamethonium, tracheal intubation, and maintenance with isoflurane 0.6% (end-tidal) and 60% nitrous oxide in oxygen. Forty-eight patients developed a heart rate of greater than 95 beats/minute or 20% more than pre-induction values at an average time of 34 minutes after tracheal intubation and received placebo (15 patients), esmolol 50 mg (16 patients), or esmolol 100 mg (17 patients). Controlled intervention was instituted if heart rate or blood pressure was not adequate. Both 50 and 100 mg of esmolol resulted in lower heart rates compared to placebo (p less than 0.05), with no difference between the two esmolol groups (p greater than 0.05). Patients who received placebo had more episodes of medical intervention than those given esmolol (p less than 0.05). No adverse effects occurred in any patient.