Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1996
Comparative StudyComparative electrophysiologic and hemodynamic effects of several amide local anesthetic drugs in anesthetized dogs.
Large and equipotent doses of several local anesthetics were administered in a cardiac electrophysiologic model on closed-chest dogs. Five groups of pentobarbital-anesthetized dogs were each given intravenously 16 mg/kg lidocaine, 12 mg/kg mepivacaine, 4 mg/kg or 8 mg/kg etidocaine, and 4 mg/kg bupivacaine. Lidocaine induced bradycardia, slowing of atrioventricular node conduction (AH), and marked hemodynamic depression, represented by a decrease in mean aortic pressure (MAoP), in the peak of first derivative of left ventricular pressure (LVdP/dt(max)) and by an increase in left ventricular end-diastolic pressure (LVEDP). ⋯ We conclude that mepivacaine induced moderate cardiotoxicity. In contrast, lidocaine induced dramatic hemodynamic depression while etidocaine and bupivacaine markedly impaired both electrophysiologic and hemodynamic variables. This double impairment could explain the great difficulty in resuscitating patients who have had cardiotoxic accidents induced by etidocaine or bupivacaine.
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Anesthesia and analgesia · Mar 1996
Randomized Controlled Trial Comparative Study Clinical TrialThe effects of bolus administration of opioids on cerebrospinal fluid pressure in patients with supratentorial lesions.
In many studies reporting an increase in cerebrospinal fluid pressure (CSFP) after opioid administration, concomitant decreases in mean arterial pressure (MAP) have been observed. Autoregulatory cerebral vasodilation may therefore have been a factor in the CSFP increases. We tested the hypothesis that increases in CSFP after bolus injection of opioids could be minimized by modifying concomitant decreases in MAP with phenylephrine. ⋯ No significant changes in MAP or CSFP were observed in the saline-treated patients. HR decreased after injection of either study drug (P < 0.01) but remained unchanged in the saline group. In summary, during stable anesthesia with isoflurane in oxygen, bolus injections of fentanyl or sufentanil, despite producing rapidly corrected mean decreases in MAP of 18% and 25%, respectively, were not associated with any change in CSFP.
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Anesthesia and analgesia · Mar 1996
Comparative Study Clinical Trial Controlled Clinical TrialCost-benefit analysis of nasal cannulae in non-tracheally intubated subjects.
We evaluated four nasal cannulae used to deliver oxygen and measure PETC02 in a non-tracheally intubated, healthy population. The effect of various oxygen flow rates on PETC02 and respiratory rate (RR), as well as the cost and relative patient comfort of the cannulae, was compared. In this controlled study, 20 healthy volunteers tested the cannulae using oxygen flow rates of 0 (breathing room air), 2, 4, and 6 L/min. ⋯ Of the nasal cannula systems evaluated in this study, the HOS system demonstrated the best cost-benefit ratio, performing well clinically while being comfortable to wear and relatively inexpensive. These conclusions are specific to a healthy population and not to patients with lung disease,those who smoke, or those having a higher ASA classification status. Our evaluation suggests that comfort and clinical performance of nasal cannulae may well depend on device design.
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Anesthesia and analgesia · Mar 1996
Comparative StudyOndansetron blocks nifedipine-induced analgesia in rats.
The serotonergic system is involved in pain transmission and the 5-hydroxytryptamine (5-HT3) receptor subtype mediates some of these effects at the spinal level. Therefore, we explored the effects of the serotonergic system on nifedipine-induced analgesia by using the 5-HT3 receptor antagonist ondansetron. Male Sprague-Dawley rats were pretreated with ondansetron (1 mg/ kg intraperitoneally) or normal saline. ⋯ Rats treated with nifedipine alone had an increase in tail-flick latency of 122%, as measured by the area under the curve, compared to rats treated with DMSO alone. Pretreatment with ondansetron, however completely blocked the analgesic effect of nifedipine, with tail-flick latency remaining at baseline throughout the measurement period. These results indicate that the 5-HT3 receptor plays an important role in the analgesic response to nifedipine and that medications that block this receptor may decrease the analgesic effectiveness of this type of therapy.
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Anesthesia and analgesia · Mar 1996
Randomized Controlled Trial Comparative Study Clinical TrialRecovery profile after desflurane with or without ondansetron compared with propofol in patients undergoing outpatient gynecological laparoscopy.
We studied the effect of combining prophylactic ondansetron (4 mg intravenously [IV]) to desflurane-based anesthesia in 90 ASA grade I or 11 women undergoing outpatient gynecological laparoscopy. Recovery after anesthesia, with special focus on postoperative nausea and vomiting (PONV), was assessed. Control groups received a similar desflurane anesthetic (placebo) or a propofol-infusion-based (active control) anesthetic. ⋯ The postoperative antiemetic requirements were consistently and significantly (P < 0.01) higher in the desflurane-only group compared to the other two groups. Postoperative sedation, analgesic requirements, and psychomotor recovery (assessed by the Maddox Wing and the Digit Symbol Substitution Tests) were similar in the three groups. Our results suggest that in order to achieve a propofol-like recovery profile in patients with a high likelihood of PONV, desflurane should be combined with a potent antiemetic (e.g., ondansetron).