Anesthesia and analgesia
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Arterial blood pressure and heart rate changes after afferent somatic sensory nerve stimulation are termed the "somatosympathetic reflex" (SSR). Inhibition of the SSR may partially represent an antinociceptive action. This investigation examined the actions of the volatile anesthetic, desflurane, on the SSR evoked by peripheral nerve stimulation. ⋯ Sciatic nerve stimulation also elicited increases in heart rate which were significantly attenuated by desflurane (control; 37 +/- 6 bpm versus 1.5 MAC desflurane; 0 +/- 2 bpm). These findings demonstrate that desflurane produces dose-dependent cardiovascular depression in rats and, despite previous reports of sympathoexcitation, desflurane significantly attenuated both excitatory and inhibitory types of SSR. The results of this study also support a potential antinociceptive action for this anesthetic.
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Anesthesia and analgesia · Jul 1996
The effect of laparoscopic cholecystectomy on cardiovascular function and pulmonary gas exchange.
Hemodynamic changes, pulmonary CO2 elimination (VECO2) and gas exchange were evaluated during laparoscopic cholecystectomy. An algorithm to calculate inspired ventilation (VI) needed to maintain constant PaCO2 was also developed. In 12 ASA physical status I patients undergoing laparoscopic cholecystectomy, heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), and systemic vascular resistance index (SVRI) were measured by the analysis of a radial artery pressure profile before, during, and after CO2 insufflation. ⋯ PaCO2.713)-1, where VA corresponds to alveolar ventilation and t must be chosen according to the pneumoperitoneum phase. We conclude that CO2 insufflation in the abdominal cavity does not induce significant changes in cardiopulmonary function in ASA physical status I patients. The algorithm proposed seems to be a useful tool for the anesthesiologists to maintain constant PaCO2 during all surgical procedures.
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Anesthesia and analgesia · Jul 1996
Randomized Controlled Trial Clinical TrialHemodynamic responses to an epinephrine test dose in adults during epidural or combined epidural-general anesthesia.
The efficacy of an epinephrine test dose during epidural and combined epidural-general anesthesia is unknown. Thirty-two patients were randomized to receive 2% lidocaine at either a high (25 mL) or low (12 mL) thoracic level of epidural anesthesia followed by general anesthesia with 1 minimum alveolar anesthetic concentration nitrous oxide and isoflurane. ⋯ Incidences of identification of intravascular injection from hemodynamic responses were similarly reduced for systolic blood pressure (100% vs 44%) and heart rate (100% vs 38%). The standard 15-micrograms epinephrine test dose is unaffected by low thoracic levels of epidural anesthesia, but may have decreased sensitivity for detection of intravascular injection during high thoracic levels of epidural anesthesia, especially during general anesthesia.