Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1995
Randomized Controlled Trial Comparative Study Clinical TrialComparative effects of esmolol and labetalol to attenuate hyperdynamic states after electroconvulsive therapy.
We studied 18 patients (age range, 53-90 yr) with at least one cardiovascular risk factor who were treated with electroconvulsive therapy (ECT) and compared effects of five pretreatments: no drug; esmolol, 1.3 or 4.4 mg/kg; or labetalol, 0.13 or 0.44 mg/kg. Each patient received all five treatments, during a series of five ECT sessions. Pretreatment was administered as a bolus within 10 s of induction or anesthesia. ⋯ The deviation of ST-segment values from baseline in any lead was not measurably influenced by either antihypertensive drug. SBP values were lower after labetalol 10 min after the seizure, but not after esmolol. Asystolic time after the seizure was not significantly longer with either drug.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Mar 1995
Randomized Controlled Trial Comparative Study Clinical TrialPharmacodynamics, pharmacokinetics, and intubation conditions after priming with three different doses of vecuronium.
The effects of three different priming doses of vecuronium on pharmacokinetics, pharmacodynamics, and endotracheal intubation conditions were investigated. Forty-two patients were studied in two parts. In each part, 21 patients were allocated into three groups (n = 7/group) receiving 10, 15, or 20 micrograms/kg vecuronium as a priming dose, followed by a 50- micrograms/kg intubating dose 6 min later. ⋯ Recovery index was significantly increased after priming with 20 micrograms/kg (13.2 +/- 6.6 min, P < 0.05) compared with 10 micrograms/kg (9.2 +/- 4.8 min) and 15 micrograms/kg (6.7 +/- 1.5 min). Between groups no differences in onset time, clinical duration, and pharmacokinetic variables were found. In Part II, onset time and intubating scores showed no significant differences between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Mar 1995
Angiotensin-converting enzyme inhibitors increase vasoconstrictor requirements after cardiopulmonary bypass.
Preoperative use of angiotensin-converting enzyme (ACE) inhibitors is common and has been associated with hypotension at separation from cardiopulmonary bypass (CPB). This study prospectively examined the influence of chronic preoperative ACE inhibitor use and other perioperative factors on the incidence of vasoconstrictor therapy required to maintain systolic blood pressure at more than 85 mm Hg despite a normal cardiac output after CPB in 4301 adults undergoing elective coronary artery and/or valve surgery. Hypothermic, nonpulsatile CPB and either opioid or ketamine-benzodiazepine anesthesia were common features of the operations. ⋯ In the first 4 h after arrival in the intensive care unit, the need for vasoconstrictor infusions to treat hypotension with adequate cardiac output did not differ, although more ACE-inhibited patients (6.4%) exhibited low values of systemic vascular resistance (< 600 dyne.s.cm-5) than patients not receiving ACE inhibitors (2.8%; P = 0.0002). Logistic regression analysis identified preoperative ACE inhibitor use, congestive heart failure, poor left ventricular function, duration of CPB, reoperative surgery, age, and opioid anesthesia as independent risk factors for requiring > or = 2 vasoconstrictor infusions after CPB. No other preoperative drug therapy significantly altered this outcome.
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Anesthesia and analgesia · Mar 1995
Effects of verapamil on spinal anesthesia with local anesthetics.
The primary mode of action of local anesthetics is through sodium channel and axonal conduction blockade. Local anesthetics also have extensive effects on presynaptic calcium channels that must function to stimulate the release of neurotransmitters. Thus, interference with calcium channel conductance may enhance spinal anesthesia with local anesthetics. ⋯ Intrathecal lidocaine or tetracaine alone showed the prolongation of TF latency, the increase of MPP threshold, and the increase in motor function scale in a time- and dose-dependent manner. Although intrathecal verapamil alone demonstrated neither sensory nor motor block at the doses used (50-200 micrograms), the combination of lidocaine (20, 50, 100, or 200 micrograms) or tetracaine (10, 20, 50, or 100 micrograms) and verapamil (50 micrograms) produced the more potent and prolonged antinociception and motor block when compared with local anesthetics alone. We interpreted these results to indicate that the intrathecal calcium channel blocker, verapamil, potentiates spinal anesthesia with local anesthetics.
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Anesthesia and analgesia · Mar 1995
Real time versus slow-motion train-of-four monitoring: a theory to explain the inaccuracy of visual assessment.
The present study was undertaken to determine why visual assessment of thumb adduction in response to train-of-four (TOF) stimulation of the ulnar nerve commonly overestimates the ratio that is obtained mechanographically. In patients undergoing general endotracheal anesthesia plus vecuronium for relaxation, 73 data sets were collected at different depths of neuromuscular block in response to supramaximal TOF stimulation. Each data set consisted of: (i) visual estimation of the TOF ratio by an experienced observer; (ii) mechanographic measurement of the TOF ratio with an adductor pollicis force transducer; and (iii) determination of the TOF ratio by measuring the slow-motion thumb displacement recorded on videotape. ⋯ When the change in thumb position as a result of T1-3 was taken into account, the measured height of T4 was 40% less than it was when measured from the original baseline, and the T4/T1 ratio was identical to that obtained mechanographically. For the 23 data sets obtained at low current visual assessment overestimated the mechanographic value to a lesser degree than when obtained at high current. Again, correction for the T1-3 baseline shift improved the accuracy of videotape analysis.(ABSTRACT TRUNCATED AT 250 WORDS)