Anesthesiology
-
Comparative Study
Percutaneous lumbar sympathectomy: a comparison of radiofrequency denervation versus phenol neurolysis.
A new percutaneous approach to sympathectomy using radiofrequency denervation has seemed to offer longer duration and less incidence of postsympathetic neuralgia as compared to phenol sympathetic blocks. To compare these techniques, 17 patients underwent either phenol lumbar sympathetic blocks (n = 9) or radiofrequency denervation (n = 8). ⋯ Results indicate that 89% of patients in the phenol group showed signs of sympathetic blockade after 8 weeks, as compared to 12% in the radiofrequency group (P less than 0.05). Although the incidence of post sympathetic neuralgia appears to be less with radiofrequency denervation, further refinement of needle placement to ensure complete lesioning of the sympathetic chain will be required before the technique can offer advantages over current phenol techniques.
-
Comparative Study
Comparison of the systemic and coronary hemodynamic actions of desflurane, isoflurane, halothane, and enflurane in the chronically instrumented dog.
The systemic and coronary hemodynamic effects of desflurane were compared to those of isoflurane, halothane, and enflurane in chronically instrumented dogs. Since autonomic nervous system function may significantly influence the hemodynamic actions of anesthetics in vivo, a series of experiments also was performed in the presence of pharmacologic blockade of the autonomic nervous system. Eight groups comprising a total of 80 experiments were performed on 10 dogs instrumented for measurement of aortic and left ventricular pressure, the peak rate of increase of left ventricular pressure (dP/dt), subendocardial segment length, coronary blood flow velocity, and cardiac output. ⋯ In summary, at equianesthetic concentrations, desflurane and isoflurane produced similar hemodynamic effects; however, in the absence of drugs that inhibit autonomic reflexes, desflurane had less negative inotropic activity and produced less decrease in arterial pressure. The coronary vasodilator actions of desflurane and isoflurane within the limitations of this model were not similar. When the increase in heart rate and rate-pressure product produced by desflurane were prevented in dogs with autonomic nervous system blockade, desflurane produced no change in coronary blood flow velocity.
-
Desflurane (difluoromethyl 1-fluoro 2,2,2-trifluoroethyl ether: CF2-H-O-CFH-CF3) is a potent inhalation anesthetic agent being investigated for possible clinical use. The authors examined the effects of this agent on normal swine and those from a special breeding program that were considered purebred for susceptibility to malignant hyperthermia (MH). Animals were exposed to 1 or 2 MAC or both doses of desflurane and observed for changes in end-tidal CO2, arterial blood gases, lactate, catecholamines, core temperature, blood pressure, and heart rate. ⋯ These latter four animals all developed episodes of MH immediately after intravenous succinylcholine (2 mg/kg). The increased PaCO2, blood lactate concentrations, and temperature, and the decrease in pH induced by desflurane, were successfully treated with dantrolene and supportive measures. All surviving animals were biopsied 1 to 2 weeks after the exposure to desflurane for in vitro contracture testing to confirm MH susceptibility.(ABSTRACT TRUNCATED AT 250 WORDS)