Transnasal butorphanol is effective for postoperative pain relief in children undergoing myringotomy.

BACKGROUND: More than 70% of children require analgesics after bilateral myringotomy and tube placement (BMT). Because anesthesia for BMT is generally provided by face mask without placement of an intravenous catheter, an alternative route for analgesia administration is needed. Transnasal butorphanol is effective in relieving postoperative pain in adults and children. The effectiveness of transnasal butorphanol for postoperative pain management in children undergoing BMT was studied. METHODS: This double-blinded, placebo-controlled study compared the postoperative analgesic effects of transnasal butorphanol administered after the induction of anesthesia. Sixty children classified as American Society of Anesthesiologists physical status 1 or 2 who were aged 6 months or older and scheduled for elective BMT were randomized to receive transnasal placebo or 5, 15, or 25 microg/kg butorphanol. Postoperative pain was assessed using the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) on arrival in the postanesthesia care unit and at 5, 10, 15, 30, 45, and 60 min. RESULTS: The CHEOP scores were significantly less in the 25 microg/kg transnasal butorphanol group compared with controls. Significantly fewer children received rescue analgesia in the 25 microg/kg transnasal butorphanol group compared with controls (n = 1 and 8, respectively; P = 0.02). CONCLUSIONS: Transnasal butorphanol given in a dose of 25 microg/kg after induction of anesthesia provided adequate postoperative pain relief in children undergoing BMT.

Perioperative management of children with third degree heart block undergoing pacemaker placement: a ten year review.

It has been suggested that children with third degree heart block require insertion of a temporary pacemaker prior to general anaesthesia. This recommendation needs to be reevaluated with the availability of noninvasive transcutaneous cardiac pacing. We undertook a retrospective ten-year chart review of anaesthesia in children with third degree heart block undergoing pacemaker insertion or revision. Forty-eight children with complete heart block underwent seventy anaesthetics of which fifty three were in children without pacemakers or with nonfunctioning pacemakers. One child had a temporary pacemaker placed preoperatively following asystole in the emergency room. In children who were not being paced, 60% had baseline heart rates less than 60 bpm. Complications seen in this study, including hypotension, would not have been prevented by temporary pacemaker placement. We conclude that there is no benefit to routine preoperative temporary pacing in children with third degree heart block.

Postoperative analgesia with preoperative oral ibuprofen or acetaminophen in children undergoing myringotomy.

Previous studies have shown over 70% of children require analgesics following bilateral myringotomy and tube placement (BM&T). This double-blind, placebo-controlled study compared the postoperative analgesic effects of preoperatively administered oral acetaminophen or ibuprofen. Forty three ASA I or II children age six months or older scheduled for elective BM&T were randomized to receive acetaminophen (paracetamol) 15 mg.kg-1, ibuprofen 10 mg.kg-1, or placebo. Postoperative pain was assessed using the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) upon arrival to the PACU and at 5, 10, 15, 30, 45, and 60 min. CHEOP scores did not differ between the groups at any time. There was no difference in the number of children receiving rescue analgesia. This study showed no benefit of preoperatively administered oral ibuprofen 10 mg.kg-1 or acetaminophen 15 mg.kg-1 over placebo for the relief of postoperative pain in children undergoing BM&T.

Neonatal hypoxia: long term effects on pulmonary arterial muscle.

The purpose of this study was to determine if neonatal hypoxia alters pulmonary arterial smooth muscle (PASM) function in young adult rats. One day old rats were made hypoxic (FIO2 = 0.1) for 5 days, then maintained under normoxic conditions until young adulthood (45-50 days). Age-matched rats were used as controls. Body weight, hematocrit, dry lung weight, and right to left heart ratios were measured. Reactivity and/or responsiveness of rings of main right and left pulmonary artery of the adult to various agonists, including high K+ (80 mM KCl), norepinephrine (NE), serotonin (5HT), adenosine (AD), and acute in vitro hypoxic vasoconstriction were assessed. Isometric force production was normalized to calculated tissue cross-sectional area (N/cm2). Maximum force production (PO) in response to 80 mM KCl for isolated rings from the hypoxic group was significantly less than for controls. Isometric force production in response to NE or to 5HT was also lower in the hypoxic group although the difference was significant for 5HT only when the endothelium was rendered non-functional. When the endothelium was intact, arterial rings from experimental animals relaxed at low doses of adenosine (10(-8) M to 10(-5) M), while control arterial muscle showed no response at these concentrations. The mean dose-response curve for NE from preparations with intact endothelium from experimental animals was significantly lower than that for the control animals, at least at doses greater than 10(-7) M. To mimic acute hypoxic pulmonary vasoconstriction, isolated rings of the main right and left pulmonary artery were precontracted with either 30 mM KCl or 2.5 x 10(-7) M NE and then made hypoxic by lowering muscle bath PO2 to 30-40 mmHg. In conclusion there was no difference in the hypoxic response per se between arterial rings from experimental animals and controls. However, maximum reactivity to high potassium stimulation and to norepinephrine stimulation is decreased in pulmonary arterial smooth muscle of adult animals that had been exposed to 5 days of hypoxia as neonates.

Anesthesia for the healthy child.

This article focuses on anesthesia for the healthy older infant and child, with nearly normal anatomy, physiology, and development, who is scheduled for an elective, relatively limited surgical procedure. Topics addressed in this section include: (1) monitoring technology used to enhance and maintain the anesthesiologist's clinical assessment; (2) pharmacological preparation designed to sedate, reduce anxiety, and/or make a child cooperative during the induction of anesthesia; (3) aspects of the induction of general anesthesia; (4) drugs commonly used for anesthetic premedication, induction, and/or maintenance; (5) aspects of emergence from anesthesia; and (6) equipment.

Biphasic contractile response of pulmonary artery to hypoxia.

Isolated perfused lungs exposed to low O2 exhibit a hypoxic pulmonary vasoconstriction response that is transient in nature. The purpose of this study was to determine whether the isolated pulmonary artery behaves similarly in response to hypoxia. Rat pulmonary arterial rings were placed in tissue baths (37 degrees C, air-5% CO2, pH = 7.4) and attached to force transducers. Maximum contractile responses (Po) to high K+ were elicited. After washout, arterial rings were submaximally contracted and made hypoxic (PO2 = 33.7 +/- 1.3, pH = 7.38 +/- 0.01). Aortic rings were used to obtain comparative data. The isolated pulmonary arterial hypoxic response was biphasic, displaying an initial rapid contraction of short duration (phase 1) then, before complete relaxation of this first response, a second slow but sustained contraction occurred (phase 2). Aortic rings did not exhibit a biphasic response, but showed only an initial short contraction followed by complete relaxation. The contractile response of the pulmonary artery was diminished when the endothelium was rendered nonfunctional. However, the phase 2 response was not endothelium dependent. Neither inhibitors of the lipoxygenase or cyclooxygenase pathways nor scavengers of extracellular reactive oxygen species had any effect on the biphasic hypoxic response. Pulmonary arterial hypoxic contractions were blunted when glucose was absent and appear to be dependent on glycolytic ATP. Results of this study show that hypoxia causes a biphasic contractile response of pulmonary arterial muscle and that two different mechanisms appear to be involved, since the transient phase 1 response is endothelium dependent, whereas the sustained contraction of phase 2 is endothelium independent.