Canadian journal of anaesthesia = Journal canadien d'anesthésie
-
The purpose of this study was to determine the importance of inhibition of beta-adrenergic function in thiopentone-induced myocardial depression. Using an isolated, electrically stimulated rat left atria model, contractile dose-response curves to thiopentone (200 microM, 400 microM, 600 microM, 800 microM) were shifted to the right in preparations treated with 10(-3)M dibutyryl cyclic adenosine monophosphate (cAMP) compared with atria stimulated with 10(-6) M dibutyryl cyclic isoprenaline, demonstrating that inhibition of beta-adrenergic mechanisms by thiopentone is physiologically important. ⋯ It is concluded that thiopentone depresses myocardial function by several mechanisms, one of which involves inhibition of the adenyl cyclase cascade. The adenyl cyclase enzyme is a likely site where thiopentone inhibits the system; however, other components of the cascade may also be involved.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Ondansetron is a better prophylactic antiemetic than droperidol for tonsillectomy in children.
Both intravenous ondansetron (OND) and droperidol (DROP) have been observed to reduce vomiting after tonsillectomy in children. This randomized, double-blind investigation compared the effect of OND and DROP on vomiting after outpatient tonsillectomy in 276 healthy children age 2-12 yr. All subjects received a standardized anaesthetic, which consisted of induction with either propofol or halothane/N2O, vecuronium 0.1 mg x kg(-1) on an as needed basis, maintenance with halothane/N2O, midazolam and codeine, and reversal of neuromuscular blockade with neostigmine and atropine on an as needed basis. ⋯ The OND-subjects required fewer rescue antiemetics, 5% vs 13%, P <0.05. The overall incidence of emesis was 45% in the OND-group and 57% in the DROP-group, P <0.05. In conclusion, ondansetron was a superior prophylactic antiemetic for tonsillectomy in children when compared to droperidol.
-
Randomized Controlled Trial Clinical Trial
Attenuation of the catecholamine response to tracheal intubation with oral clonidine in children.
We conducted a prospective, randomized, double-blind , controlled clinical trial to examine (1) whether plasma catecholamine (CA) concentrations increased in response to tracheal intubation in children, and (2) the effects of clonidine on the CA responses. Sixty children (ASA physical status I) aged 7-13 yr were allocated to one of three groups (n = 20 for each group): diazepam 0.4 x kg(-1) (active control), clonidine 2 micrograms x kg(-1), or clonidine 4 micrograms x kg(-1) po. These agents were administered 105 min before induction of anaesthesia followed by oral atropine 0.03 mg x kg(-1) given 60 min before anaesthesia which was induced with thiamylal 5 mg x kg(-1) and tracheal intubation was facilitated with vecuronium 0.2 mg x kg(-1). ⋯ These haemodynamic and CA changes were smaller in children receiving clonidine 4 micrograms x kg(-1) (P < 0.005). The haemodynamic responses were positively correlated with the CA responses. These findings indicate that tracheal intubation following rapid sequence induction of anaesthesia in children provokes a reflex increase in sympathetic activity characterized by increased plasma CA concentrations, and that attenuation of the cardiovascular changes with a high oral dose of clonidine may be due to suppression of the increase in sympathetic activity evoked by the intubation.
-
The purpose of this article is to review the literature on the side effects of intrathecal and epidural opioids. English-language articles were identified through a MEDLINE search and through review of the bibliographies of identified articles. With the increasing utilization of intrathecal and epidural opioids in humans during the 1980s, a wide variety of clinically relevant side effects have been reported. ⋯ It is concluded that the introduction of intrathecal and epidural opioids marks one of the most important breakthroughs in pain management in the last two decades. However, a wide variety of clinically relevant non-nociceptive side effects may occur. All physicians utilizing intrathecal and epidural opioids must be aware of these side effects, for while most are minor, others are potentially lethal.