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Biomedical subjects

D Duncalf

Publications and source records attributed to D Duncalf.

51 records · Page 3Linked to original sources
PubMedDate not supplied

A double-blind, placebo-controlled pilot study examining the effectiveness of intravenous ondansetron in the prevention of postoperative nausea and emesis.

STUDY OBJECTIVE: To compare the efficacy and safety profiles of ondansetron and a placebo when infused immediately prior to anesthesia induction for the prevention of postoperative nausea and emesis (vomiting or retching). DESIGN: Randomized, double-blind, placebo-controlled, parallel, multicenter pilot study. SETTING: Three U.S. ambulatory surgical facilities. PATIENTS: One hundred eighty ASA physical status I and II women scheduled to undergo ambulatory gynecologic surgical procedures while receiving general endotracheal anesthesia. INTERVENTIONS: Ondansetron 8 mg or a placebo (equivalent volume) was given intravenously (IV) prior to anesthesia induction to prevent postoperative nausea and vomiting. MEASUREMENTS AND MAIN RESULTS: For the first 24 hours following emergency from anesthesia, patients were monitored in the postanesthesia care unit by a research observer and at home via telephone contact and diary cards. More patients in the ondansetron group (62%) than in the placebo group (40%) were emesis-free over the 24-hour study period (p = 0.005). Ondansetron also was more efficacious than the placebo over the 24-hour study period when a surgery duration of more than 45 minutes was considered in the analyses. For all patients, regardless of surgery duration, there was a low degree of nausea during the course of the study. In all instances, the degree of nausea was slightly lower for ondansetron-treated patients than for placebo-treated patients; however, in no instances were the differences statistically significant. Ondansetron and placebo had similar safety profiles as established by laboratory test results, vital sign monitoring, and adverse event reporting. CONCLUSION: Ondansetron, infused IV before anesthesia induction, appears to be safe and effective when used in the prevention of postoperative nausea and emesis.

Adult↗
PubMedDate not supplied

Naloxone fails to antagonize thiopental anesthesia.

A study was undertaken to determine the effect in man of naloxone on the central nervous system depression produced by IV thiopental. Eight normal volunteers were given 5 mg/kg thiopental IV. On a separate occasion the same 8 volunteers were given 50 microgram/kg naloxone IV 5 minutes prior to 5 mg/kg thiopental. Naloxone had no significant effect on the rate of return of consciousness following administration of thiopental. Naloxone also had no significant effect on the responses of blood pressure, heart rate, or respiratory rate to thiopental.

Adult↗
PubMedDate not supplied

Naloxone fails to antagonize halothane-induced depression of the longitudinal muscle of the guinea pig ileum.

The influence of halothane, or naloxone, or halothane followed by naloxone was investigated in the in vitro myenteric plexus longitudinal muscle preparation of the guinea pig ileum. Halothane alone in 1.5 to 2.0% (v/v) concentration caused about 50% depression of the twitch and decreased both spontaneous acetylcholine (ACh) release (p less than 0.02) and volley output of ACh (p less than 0.02). Very high concentrations (greater than 1 micron) of naloxone caused a nonspecific, postsynaptic depression of the twitch. Higher than 100 nM concentrations of naloxone increased spontaneous ACh release, but had no effect on the volley output of ACh. Over a wide concentration range, from 15 nM to 3 micron, naloxone did not antagonize in the longitudinal muscle preparation the effects of halothane on any of the parameters investigated. These findings indicate that the sites of action of halothane and naloxone in this preparation are not identical.

Acetylcholine↗
PubMedDate not supplied

In vitro comparison of the neuromuscular antinicotinic and intestinal antimuscarinic effects of different nondepolarizing muscle relaxants.

The postsynaptic antimuscarinic properties of different nondepolarizing muscle relaxants were compared with their postsynaptic antinicotinic effect. d-Tubocurarine, pipecuronium and vecuronium were the most selective antagonists on postsynaptic nicotinic receptors. Gallamine, diadonium and Duador (RGH-4201) had relatively greater effect on postsynaptic muscarinic receptors. Therefore, much less side effect is expected to occur when pipecuronium, d-tubocurarine or vecuronium are used.

Animals↗
PubMedDate not supplied

Alterations in cardiovascular function during neurolept anesthesia for surgery on the coronary vessels.

Induction of anesthesia for aortocoronary bypass surgery was accomplished by the administration of droperidol, morphine, oxygen and nitrous oxide-oxygen in 20 patients. They ranged from 40 to 69 years of age. Premedication consisted of diphenhydramine and morphine. Cardiovascular stability was the most important aspect of the technique. Heart rate changes were insignificant. Cardiac index increased substantially after droperiodol and remained unchanged after morphine. It stayed around control levels for the rest of the induction. A substantial decrease was observed while using mechanical ventilation. Mean arterial pressure dropped significantly after droperidol and again after morphine, then rose about 17% after oxygen to near control levels, where it stayed thereafter. Peripheral vascular resistance dropped substantially after droperidol. A significant increase occurred after oxygen, reaching almost control levels at this point. Mechanical ventilation caused a significant increase, similar to the decrease in the cardiac index. Decreased oxygen availability was compensated for by decreased oxygen consumption. Induction of neurolept anesthesia in the manner described appears to be void of the undesirable effects of either large doses of morphine, or nitrous oxide-oxygen following such morphine doses. Amnesia was complete in every patient.

Adult↗