Anesthesiology
-
Randomized Controlled Trial Clinical Trial
Preemptive analgesia. Clinical evidence of neuroplasticity contributing to postoperative pain.
Recent evidence suggests that surgical incision and other noxious perioperative events may induce prolonged changes in central neural function that later contribute to postoperative pain. The present study tested the hypothesis that patients receiving epidural fentanyl before incision would have less pain and need fewer analgesics post-operatively than patients receiving the same dose of epidural fentanyl after incision. Thirty patients (ASA physical status 2) scheduled for elective thoracic surgery through a posterolateral thoracotomy incision were randomized to one of two groups of equal size and prospectively studied in a double-blind manner. ⋯ Paralysis was achieved with pancuronium (0.1 mg/kg). Postoperative analgesia consisted of patient-controlled intravenous morphine. Visual analogue scale pain scores were significantly less in group 1 (2.6 +/- 0.44) than in group 2 (4.7 +/- 0.58) 6 h after surgery (P less than 0.05), by which time plasma fentanyl concentrations had decreased to subtherapeutic levels (less than 0.15 ng/ml) in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Randomized Controlled Trial Clinical Trial
Transdermal fentanyl for postoperative pain management in patients recovering from abdominal gynecologic surgery.
The current placebo-controlled double-blinded study was undertaken to assess the safety and efficacy, as well as the potential clinical role, of the transdermal therapeutic system (TTS) of fentanyl delivery in the postoperative setting. TTS patches releasing 25 micrograms.h-1 or 50 micrograms.h-1 or placebo were applied to 95 women 1 h before abdominal gynecologic surgery during general anesthesia. Postoperatively, patients self-administered intravenous morphine as required using patient-controlled analgesia with a 1-mg incremental dose and a 6-min lockout interval. ⋯ Beginning 32 h after TTS application, a statistically significant morphine-sparing effect was seen with the 50 micrograms.h-1 patch. There were no significant differences among groups with regard to visual analogue scale pain scores at rest, patient satisfaction, or the incidence of side effects; a significant reduction in pain upon movement was noted at 24 h in patients treated with TTS 50 micrograms.h-1. This finding constituted the only benefit noted with this form of analgesic therapy in the present investigation.
-
Randomized Controlled Trial Clinical Trial
Ondansetron does not affect alfentanil-induced ventilatory depression or sedation.
Ondansetron is a selective 5-hydroxytryptamine type 3 receptor antagonist effective as an antiemetic in patients experiencing post-operative or cancer chemotherapy-induced nausea and vomiting. Currently, no information is available regarding the interaction of ondansetron with opioids, although a serotonin antagonist might be expected to modify some opioid actions. This study was designed to measure the effects of ondansetron on alfentanil-induced ventilatory depression and sedation in healthy male volunteers. ⋯ Neither placebo nor ondansetron produced further change in the intensity of either alfentanil effect. After discontinuation of the opioid, both ventilatory depression and sedation decreased, and the rate of recovery was not significantly different between groups. The data indicate that alfentanil-induced sedation and ventilatory depression are not significantly affected by the subsequent administration of ondansetron.
-
Comparative Study
Effects of sevoflurane and isoflurane on hepatic circulation in the chronically instrumented dog.
To compare the effects of sevoflurane and isoflurane on hepatic circulation, eighteen dogs were chronically instrumented for measurements of mean aortic blood pressure and cardiac output and for simultaneous measurements of hepatic and portal blood flows. Each animal was studied while awake and during 1.2 and 2 MAC of either isoflurane or sevoflurane. Both anesthetics induced tachycardia and a dose-dependent decrease in mean aortic blood pressure (isoflurane -27% and -39%; sevoflurane -22% and -37%). ⋯ During isoflurane, the only significant change was a decrease in portal blood flow (-16%) at 1.2 MAC. Neither anesthetic significantly changed renal blood flow. Therefore, both anesthetics led to similar systemic and hepatic vasodilation.
-
Comparative Study
Premedication with oral dexmedetomidine alters hemodynamic actions of intravenous anesthetic agents in chronically instrumented dogs.
Dexmedetomidine (the D-stereoisomer of medetomidine), a highly selective alpha 2-adrenoceptor agonist, has been demonstrated to produce analgesia and sedation and attenuate hemodynamic responses to emergence from inhalational anesthetics, which suggests a potential use for this drug as a premedicant for general anesthesia. The authors examined hemodynamic interactions between dexmedetomidine and three commonly used intravenous anesthetic agents with markedly different hemodynamic effects. Conscious, chronically instrumented dogs received intravenous induction doses of ketamine, propofol, or etomidate, followed by continuous infusions of each drug at four different doses for 15-min intervals on different days. ⋯ However, ketamine significantly reduced left ventricular dP/dt50 compared to control in dogs premedicated with dexmedetomidine. Except for a significant reduction in systemic vascular resistance, dexmedetomidine did not significantly affect the hemodynamic response to induction of anesthesia with propofol. Similarly, dexmedetomidine did little to alter the hemodynamic response to induction of anesthesia with etomidate.(ABSTRACT TRUNCATED AT 250 WORDS)