Christopher L. Wu

Ondansetron decreases emesis after tonsillectomy in children

We performed a double-blind, randomized, placebo-controlled trial to investigate the efficacy and safety of ondansetron in preventing vomiting after tonsillectomy with or without adenoidectomy in children. Sixty children were premedicated with 0.5 mg/kg of oral midazolam and underwent inhaled induction and maintenance of anesthesia with halothane and nitrous oxide. Intravenous morphine 0.075 mg/kg, vecuronium 0.1 mg/kg, and either ondansetron 0.15 mg/kg (maximum = 8 mg), or saline placebo were administered after intravenous catheter placement. All episodes of postoperative vomiting on the day of surgery and the following day were recorded. There were no significant differences between the two groups with regard to age, weight, sex, time to endotracheal intubation, duration of surgery, duration of anesthesia, or number of patients having adenoidectomy. More patients in the ondansetron group received dexamethasone as part of the surgeons routine protocol (P = 0.03). Twenty-three children (77%) who received ondansetron were emesis-free as opposed to only eight (27%) in the placebo group (P < 0.001). This was especially evident in the number of children who had two or more episodes of vomiting; 17 children (57%) who received placebo had two or more episodes of vomiting as opposed to only two children (7%) who received ondansetron. The incidence of emesis on the day after the surgery did not differ between the two groups. Three children who received ondansetron and one who received placebo complained of abdominal cramping on the night of the surgery. There were no other complaints or complications. Analysis of the 51 children who did not receive dexamethasone revealed similar results.(ABSTRACT TRUNCATED AT 250 WORDS)

Thoracic Epidural Analgesia versus Intravenous Patient-controlled Analgesia for the Treatment of Rib Fracture Pain after Motor Vehicle Crash

BACKGROUNDnPain from rib fracture pain may affect pulmonary function, morbidity, and length of intensive care unit stay. Previous trials have varied epidural technique within the study and have used several outcome variables.nnnMETHODSnThe charts of patients who sustained rib fractures after a motor vehicle crash between January 1, 1994, and June 30, 1997, were reviewed. Data were collected from 64 patients who had three or more rib fractures and initiation of intravenous patient-controlled analgesia with morphine or thoracic epidural analgesia with bupivacaine and fentanyl within 24 hours of admission.nnnRESULTSnInjury Severity Score and Acute Physiology and Chronic Health Evaluation II scores were not significantly different between groups. Patients in the epidural group had significantly more rib fractures and were significantly older. Patients who received epidural analgesia had significantly lower pain scores at all times. There were no differences in the lengths of intensive care unit or hospital stays, or the incidence of pulmonary complications or organ failure between groups.nnnCONCLUSIONnThoracic epidural analgesia with bupivacaine and fentanyl provided superior analgesia than intravenous patient-controlled analgesia morphine.

Gastric volume and pH in infants fed clear liquids and breast milk prior to surgery

Recommendations for fasting intervals prior to anesthesia in pediatric patients have changed in recent years. There are few data concerning infants less than 1 yr of age fed clear liquids or breast milk before surgery. We performed a prospective, blinded study to determine residual gastric volumes and pH in this population. Approximately 2 h prior to surgery, 46 formula-fed infants ingested up to 8 oz of clear liquids and 24 breast-fed infants nursed as usual. After induction of general anesthesia and tracheal intubation, gastric fluid samples were aspirated by a blinded researcher who measured gastric volume and pH. Sufficient gastric fluid for analysis was obtained from 10 (22%) of the infants fed clear liquids and 8 (33%) of the breast-fed infants. For the group fed clear liquids, the residual gastric volume was 0.3 +/- 0.9 mL/kg and the pH was 2.1 +/- 1.4. Eight (17%) had gastric volumes > or = 0.4 mL/kg, 2 (4%) had gastric volumes > or = 1 mL/kg, and 9 (90%) of 10 measured had pH < or = 2.5. In the breast-fed group the residual gastric volume was 0.71 +/- 1.1 mL/kg (P = not significant [NS]) and the pH was 2.6 +/- 1 (P = NS). All eight (33%) breast-fed infants had gastric volumes > or = 0.4 mL/kg (P = NS), seven (29%) had gastric volumes > or = 1 mL/kg (P = 0.03), and four (50%) of eight measured had pH < or = 2.5 (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Midazolam Premedication Increases Sedation but Does Not Prolong Discharge Times After Brief Outpatient General Anesthesia for Laparoscopic Tubal Sterilization

Preoperatively administered midazolam may contribute to postoperative sedation and delayed recovery from brief outpatient general anesthesia, particularly in patients who receive significant postoperative opioid analgesics.We evaluated the effects of midazolam premedication (0.04 mg/kg) on postoperative sedation and recovery times after laparoscopic tubal sterilization (Falope rings) in 30 healthy women in a randomized, double-blind, placebo-controlled study. Patients received midazolam or saline-placebo intravenously 10 min before anesthesia. General anesthesia was induced with fentanyl, propofol, and mivacurium and was maintained with N2 O and isoflurane. Sedation was quantified before and after premedication and 15, 30, and 60 min after emergence from anesthesia, using the digit-symbol substitution (DSST) and Trieger dot (TDT) tests. Management of postoperative pain and nausea and discharge criteria were standardized. Groups were similar with respect to age, weight, and duration of surgery and anesthesia. Midazolam was associated with impairment of performance on the TDT and DSST after premedication administration and 15 (TDT and DSST) and 30 (DSST) min after postanesthesia care unit (PACU) arrival. There were no differences in PACU time and time to discharge-readiness. In conclusion, midazolam premedication augments postoperative sedation in this population but does not prolong recovery times. (Anesth Analg 1997;85:301-5)

Accidental overdose of systemic morphine during intended refill of intrathecal infusion device.

ntrathecal morphine is an effective and wellrecognized method of alleviating intractable pain I in cancer patients (1,2). Several implantable systems have been developed to facilitate delivery of opioids on a long-term basis (3). Some of these devices incorporate a drug reservoir to eliminate the need for frequent injections and externalized hardware. When refilling the reservoir, there is the potential for a misplaced injection of a relatively large dose of opioid. This may occur despite the presence of alarm features. This report describes a case of an accidental massive, nonfatal overdose of subcutaneous morphine that occurred in the course of refilling the reservoir of a Medtronics Synchromed infusion Pump.

Nondepolarizing neuromuscular blockers inhibit the serotonin-type 3A receptor expressed in xenopus oocytes

UNLABELLEDnMolecular cloning and sequence comparison indicates a high degree of structural homology between muscle nicotinic acetylcholine (nACh) and serotonin-type 3 (5-HT(3A)) receptors, both members of the direct ligand-gated family of ion channels. Because of the structural similarities and common evolutionary origin of these receptors, neuromuscular blockers (competitive nACh antagonists) may demonstrate pharmacologic cross talk and exhibit attributes of 5-HT(3A) receptor antagonists. We examined six clinically-used neuromuscular blockers for their ability to antagonize currents flowing through the 5-HT(3A) receptors in voltage clamped Xenopus oocytes. The neuromuscular blockers reversibly inhibited the 5-HT(3A) receptor-gated current in the rank order potency of (IC50 mean +/- SEM): d-tubocurarine (0.046 +/- 0.003 microM), atracurium (0.40 +/- 0.03 microM), mivacurium (15.1 +/- 2.93 microM), vecuronium (16.3 +/- 2.24 microM), and rocuronium (19.5 +/- 2.31 microM). Gallamine was essentially inactive as a 5-HT(3A) receptor antagonist with an extrapolated IC50 of 1170 microM. We demonstrate that drugs classically known as competitive nACh receptor antagonists also block 5-HT(3A) receptors. It is likely that certain neuromuscular blockers share pharmacological properties with 5-HT(3A) receptor antagonists, such as a reduction in postoperative nausea and vomiting. With careful drug selection, pharmacological cross talk could potentially be used to minimize polypharmacy and optimize patient management.nnnIMPLICATIONSnMuscle nicotinic acetylcholine and serotonin-type 3A (5-HT(3A)) receptors are similar. Therefore neuromuscular relaxants may block 5-HT(3A) receptors. Our pharmacological study demonstrates that neuromuscular relaxants, as with ondansetron, are 5-HT(3A) receptor antagonists. It is likely that certain neuromuscular relaxants exhibit ondansetron-like clinical properties, such as reduction in postoperative nausea and vomiting.

Perioperative stroke associated with postoperative epidural analgesia

A patient with an epidural catheter for postoperative analgesia developed a stroke in association with a hypotensive episode resulting from a bolus of local anesthetic. After undergoing resection for femoral chondrosarcoma under epidural anesthesia, the patient received a continuous infusion of epidural morphine for postoperative analgesia. Lidocaine 1% (10 mL in divided doses) was administered through the catheter for breakthrough pain. The patient experienced a hypotensive episode and was noted to have a motor and cortical sensory deficit of the left arm and leg 8 hours after the hypotensive episode. Clinical presentation and subsequent workup were consistent with a watershed infarction. The patient recovered full neurologic function before discharge. Postoperative hypotension from epidural analgesia may be associated with stroke; however, a cause-and-effect relationship usually cannot be established with certainty.

PAR1 inhibition suppresses the self-renewal and growth of A2B5-defined glioma progenitor cells and their derived gliomas in vivo

Glioblastoma (GBM) remains the most common and lethal intracranial tumor. In a comparison of gene expression by A2B5-defined tumor-initiating progenitor cells (TPCs) to glial progenitor cells derived from normal adult human brain, we found that the F2R gene encoding PAR1 was differentially overexpressed by A2B5-sorted TPCs isolated from gliomas at all stages of malignant development. In this study, we asked if PAR1 is causally associated with glioma progression. Lentiviral knockdown of PAR1 inhibited the expansion and self-renewal of human GBM-derived A2B5+ TPCs in vitro, while pharmacological inhibition of PAR 1 similarly slowed both the growth and migration of A2B5+ TPCs in culture. In addition, PAR1 silencing potently suppressed tumor expansion in vivo, and significantly prolonged the survival of mice following intracranial transplantation of human TPCs. These data strongly suggest the importance of PAR1 to the self-renewal and tumorigenicity of A2B5-defined glioma TPCs; as such, the abrogation of PAR1-dependent signaling pathways may prove a promising strategy for gliomas.

Anaesthetic management for a child with the Ellis-van Creveld syndrome: a case report

Summary