Anesthesiology
-
Hypothermia in anesthetized adults provokes centrally mediated, peripheral thermoregulatory vasoconstriction at threshold temperatures approximately 2.5 degrees C below normal. The weight dependence of thermoregulatory vasoconstriction was evaluated in 33 unpremedicated pediatric patients receiving isoflurane/oxygen anesthesia (end-tidal concentrations approximately 0.9%) and caudal anesthesia with bupivacaine. The patients were prospectively assigned to four weight groups (5-10 kg, 10-20 kg, 20-30 kg, and 30-50 kg). ⋯ Vasoconstriction occurred in 32 of the patients at temperatures ranging from 34.4 to 35.3 degrees C. Central and mean body threshold temperatures did not differ among the groups, and were similar to those observed previously in adults. There was a good correlation between laser Doppler flowmetry and forearm-fingertip skin temperature gradients in individual patients.
-
The antinociceptive interaction on the tail flick (TF) and hot plate (HP) tests between opioid analgesics and medetomidine after intravenous (iv) or intrathecal administration were examined by isobolographic analysis. Male Sprague-Dawley rats received fixed ratios of medetomidine to morphine, fentanyl, and meperidine of 1:10 and 1:30, 10:1, and 1:3, respectively, by iv administration or 10:1, 3:1 and 10:1, and 1:3 by intrathecal administration, respectively. Data were expressed as the percentage maximal possible effect (%MPE). ⋯ These data confirmed that the interaction between medetomidine and opioids in producing antinociception may be additive or synergistic, depending on the route of administration, drug ratio administered, and level of processing of the nociceptive input (i.e., spinal vs. supraspinal). Moreover, these results were consistent with a spinal role for alpha-2 adrenoceptors in mediating antinociception. The authors suggest that the interaction between the opioid and alpha-2 adrenergic receptors occurs within the spinal cord.
-
Comment Letter Case Reports
Knotting of the Theracath after an uneventful epidural insertion for cesarean delivery.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Oral midazolam preanesthetic medication in pediatric outpatients.
A need exists for a safe and effective oral preanesthetic medication for use in children undergoing elective surgical procedures. We evaluated the effectiveness of three different doses of oral midazolam when administered in combination with atropine prior to ambulatory surgery. In this randomized, double-blind, placebo-controlled study, 124 children, ages 1-10 yr, received midazolam, 0.25, 0.50, or 0.75 mg.kg-1 po, and atropine, 0.03 mg.kg-1 po, mixed with apple juice, or a placebo (containing the midazolam vehicle, atropine, and apple juice). ⋯ Midazolam 0.75 mg.kg-1 produced significant sedation at 30 min. After procedures lasting an average of 106-113 min, recovery was not prolonged by the oral midazolam-atropine combination. We concluded that oral midazolam 0.5-0.75 mg.kg-1 is an effective preanesthetic medication for pediatric outpatients.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Anesthesia for craniotomy: a double-blind comparison of alfentanil, fentanyl, and sufentanil.
Using a prospective, randomized, and double-blind study design, alfentanil (n = 15), fentanyl (n = 14), or sufentanil (n = 16), in combination with N2O, were administered to patients undergoing craniotomy for supratentorial tumor resection. Physicians were given two syringes, one of which was labeled as "load" for the initial loading dose and the other as "maintenance" for continuous infusion. The concentration of drug in each syringe was adjusted to permit administration on a milliliter per kilogram basis. ⋯ Administration of isoflurane, antihypertensive medications, and naloxone were not different among groups. Although decreases in blood pressure seen with induction were similar among groups, alfentanil-treated patients received ephedrine more frequently before intubation. Thirty minutes after entry into the postanesthesia recovery area, respiratory rate and pH were lowest in sufentanil-treated patients.(ABSTRACT TRUNCATED AT 250 WORDS)