Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1989
Comparative StudyHemodynamic and cardiodynamic effects of propofol and etomidate: negative inotropic properties of propofol.
The hemodynamic effects of an induction dose of propofol, 2.5 mg/kg, or etomidate, 0.3 mg/kg, were studied in eight dogs. In addition, cardiodynamic changes were measured using a left ventricular catheter and needle force probes. Propofol was associated with significant decreases in systolic (19.9%) and diastolic (25.3%) arterial pressures associated with a 17.3% decrease in cardiac output (CO) and a 11.6% reduction in systemic vascular resistance (SVR) without change in pulmonary capillary wedge pressure (PCWP). ⋯ Signals generated by the force probes in the left ventricular myocardium showed a significant reduction (16.3%) in left ventricular force (LVF) and a decrease in early systolic rates of increase in force (dF/dt max) by 23.5% associated with propofol. In the presence of an unchanged preload, an unchanged HR, and a decreased SVR, the reduction in CO suggests that propofol has a negative inotropic effect. This negative inotropic effect was confirmed by a reduction in LVF and dF/dt max.
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Anesthesia and analgesia · Jul 1989
Comparative StudyComparison of tracheal intubating conditions and neuromuscular blocking profiles after intubating doses of mivacurium chloride or succinylcholine in surgical outpatients.
Thirty ASA physical status I or II outpatients scheduled to undergo short procedures (less than 1 hr in duration) requiring tracheal intubation received either 1.0 mg/kg succinylcholine or 0.20 mg/kg (2.5 x ED95) or 0.25 mg/kg (3 x ED95) mivacurium. A N2O/O2/narcotic anesthetic technique was utilized and the ulnar nerve was stimulated with subcutaneous electrodes placed at the wrist. Tracheal intubation was attempted in all patients either 2 min after mivacurium or 1 min after succinylcholine. ⋯ The mean infusion rates were 6.6 micrograms.kg-1.min-1 mivacurium and 41.2 micrograms.kg-1.min-1 for succinylcholine. Spontaneous recovery from neuromuscular blockade occurred more quickly after succinylcholine than after mivacurium: the time from cessation of infusion to recovery of T1 to 95% of baseline was 6.5 min in patients given succinylcholine and 16.7 min in patients given mivacurium. When reversal was in order, residual mivacurium-induced blockade was readily antagonized by 0.045 mg/kg neostigmine.(ABSTRACT TRUNCATED AT 250 WORDS)
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Fifty-four patients developed severe intercostal neuralgia a few weeks after sternotomy. Immediate relief afforded by parasternal nerve blocks confirmed that the pain derived from scar-entrapped neuromas of the anterior rami of the first 4-6 intercostal nerves in the upper (and mainly left) interchondral spaces after insertion of the sternal wires. Permanent relief (i.e., over 6 months) followed repeated bupivacaine blocks in 57.4% of the patients, phenol blocks in another 22.2%, and alcohol blocks in a remaining 9%. Treatment was successful in 87% of the patients.
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Anesthesia and analgesia · Jul 1989
Comparative StudyDiffering effect of agonist and antagonist muscle relaxants on cat jaw muscles.
Mouth closure and an increased resistance to mouth opening follow succinylcholine administration in humans. To elucidate the effects of succinylcholine on masticatory muscle function, mouth opening in the cat, produced by a constant test force, was measured during steady state halothane anesthesia. After baseline measurements, either succinylcholine (0.3 mg.kg-1 of body weight) or vecuronium (0.1 mg.kg-1 of body weight) was infused intravenously, and mouth opening measurements were repeated for up to 30 min. ⋯ Vecuronium administration was associated with a decreased resistance to mouth opening without a closing action. The initial jaw closure and the subsequently increased resistance to mouth opening after succinylcholine administration during halothane anesthesia in the cat are comparable with mouth opening changes after succinylcholine administration during inhalation anesthesia in humans. The cat may serve as an animal model for study of the mechanisms involved in responses of jaw muscles to succinylcholine with use of techniques inappropriate in humans.