Lynne G. Maxwell

Preinduction of Anesthesia in Children with Rectally Administered Midazolam

The authors evaluated the efficacy of rectally administered midazolam for preinduction (i.e., premedication/induction) of anesthesia in 67 pediatric patients, ASA physical status 1 or 2, undergoing a variety of elective surgical procedures. In phase 1, 41 children weighing 12 +/- 3 kg (range 7-20 kg) and 31 +/- 16 months (range 8-67 months) of age (mean +/- SD) received midazolam, 0.4-5.0 mg.kg-1, in an attempt to produce unconsciousness. Only one child lost consciousness (4.5 mg.kg-1). However, at all doses, inhalational induction of anesthesia was facilitated because children were tranquil and calmly separated from their parent(s). There were no clinically significant changes in arterial blood pressure, heart rate, oxyhemoglobin saturation, and end-tidal carbon dioxide concentration, 10 min after drug administration. In phase 2, 26 children weighing 17 +/- 4 kg (range 10-26 kg) and 44 +/- 19 months (range 17-84 months) months of age undergoing tonsil and/or adenoid surgery were studied to determine the optimal sedative dose of rectally administered midazolam. Patients received 0.3, 1.0, 2.0, or 3.0 mg.kg-1 of midazolam in a randomized, double-blind fashion. One third (3 of 9) of patients receiving 0.3 mg.kg-1 struggled during mask induction. All patients receiving greater than or equal to 1.0 mg.kg-1 were adequately sedated (P less than 0.008). Discharge from the postanesthesia care unit (PACU), however, was delayed (greater than 60 min) in children receiving greater than or equal to 2.0 mg.kg-1 (P less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. I. Emergence and recovery profiles

Pyloric stenosis is sometimes associated with hemodynamic instability and postoperative apnea. In this multicenter study we examined the hemodynamic response and recovery profile of remifentanil and compared it with that of halothane in infants undergoing pyloromyotomy. After atropine, propofol, and succinylcholine administration and tracheal intubation, patients were randomized (2:1 ratio) to receive either remifentanil with nitrous oxide and oxygen or halothane with nitrous oxide and oxygen as the maintenance anesthetic. Pre- and postoperative pneumograms were done and evaluated by an observer blinded to the study. Intraoperative hemodynamic data and postanesthesia care unit (PACU) discharge times, PACU recovery scores, pain medications, and adverse events (vomiting, bradycardia, dysrhythmia, and hypoxemia) were recorded by the study’s research nurse. There were no significant differences in patient age or weight between the two groups. There were no significant differences in hemodynamic values between the two groups at the various intraoperative stress points. The extubation times, PACU discharge times, pain medications, and adverse events were similar for both groups. No patient anesthetized with remifentanil who had a normal preoperative pneumogram had an abnormal postoperative pneumogram, whereas three patients with a normal preoperative pneumogram who were anesthetized with halothane had abnormal pneumograms after.

Polysomnography after adenotonsillectomy in mild pediatric obstructive sleep apnea

OBJECTIVES a) To determine the need for intensive monitoring on the first operative night of surgery in children undergoing adenotonsillectomy for mild obstructive sleep apnea; b) to examine the effect of narcotics on postoperative obstructive sleep apnea. DESIGN Randomized, prospective study. SETTING University hospital. PATIENTS Children, ranging in age between 1 and 18 yrs, presented to the Pediatric Otolaryngology Clinic for adenotonsillectomy for mild obstructive sleep apnea defined as from one to 15 obstructive apnea events per hour on preoperative polysomnogram. INTERVENTIONS Patients were assigned to receive either a narcotic- or a halothane-based anesthetic for adenotonsillectomy. A postoperative polysomnogram was performed in the pediatric intensive care unit on the first operative night. MEASUREMENTS AND MAIN RESULTS Eighteen patients were recruited, 15 of whom met inclusion criteria: nine patients received a halothane-based anesthetic and six patients received a fentanyl-based anesthetic. When the data were analyzed by pooling both groups, the differences between pre- and postoperative sleep studies demonstrated a reduction in the number of obstructive events and less severe oxygen desaturations on the operative night. Total sleep time between the two sleep studies decreased from 371 +/- 13 to 304 +/- 14 mins. The number of obstructive apnea events/hr decreased as well. The lowest oxygen saturation measured during rapid eye movement sleep was 78 +/- 5% preoperatively and 92 +/- 1% postoperatively. CONCLUSIONS Our data suggest that children without underlying medical conditions, neuromotor diseases, or carniofacial abnormalities, 1 to 18 yrs of age, who suffer from mild obstructive sleep apnea, have improvements documented by polysomnography on the night of surgery following adenotonsillectomy and do not necessarily need to be monitored intensively. These findings were not significantly affected by the choice of intraoperative anesthetic.

A randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. II. Perioperative breathing patterns in neonates and infants with pyloric stenosis

Although former preterm birth infants are at risk for postoperative apnea after surgery, it is unclear whether the same is true of full-term birth infants. We evaluated the incidence of apnea in 60 full-term neonates and infants undergoing pyloromyotomy both before and after anesthesia. All subjects were randomized to a remifentanil- or halothane-based anesthetic. Apnea was defined by the presence of prolonged apnea (>15 s) or frequent brief apnea, as observed on the pneumocardiogram. Apnea occurred before surgery in 27% of subjects and after surgery in 16% of subjects, with no significant difference between subjects randomized to remifentanil or halothane anesthesia. This apnea was primarily central in origin, occurred throughout the recording epochs, and was associated with severe desaturation in some instances. Of the subjects with normal preoperative pneumocardiograms, new onset postoperative apnea occurred in 3 (23%) of 13 subjects who received halothane-based anesthetics versus 0 (0%) of 22 subjects who received remifentanil-based anesthetics (P = 0.04). Thus, postoperative apnea can follow anesthesia in otherwise healthy full-term infants after pyloromyotomy and is occasionally severe with desaturation. New-onset postoperative apnea was not seen with a remifentanil-based anesthetic.

The management of pain in sickle cell disease

The pain of vaso-occlusive crisis in patients with sickle cell disease is excruciating, incapacitating, and sometimes refractory to even the most advanced analgesic treatments. A comprehensive, multimodal approach to therapy that includes education, cognitive therapies, anti-inflammatory drugs, opioids, and psychostimulant adjuvant drugs has been presented. Until a cure for the underlying disease is found, these are the best approaches available. The authors hope that future research will find even better modalities of analgesic care.

Postoperative Analgesia: Use of Intrathecal Morphine in Children

The identification of opiate receptors in the spinal cord gave rise to the suggestion that the use of intrathecal and epidural narcotics may provide effective and safe postoperative analgesia. The authors retrospectively reviewed the records of ten children who received intrathecal morphine as part of their anesthetic care over the last 2 years. Preservative-free morphine (Duramorph®) in a dose of 0.02 mg/kg was administered to all patients in the lumbar intrathecal space before the start of the surgical procedure. Adequate postoperative analgesia was achieved in the ten children. No patient required supplemental analgesic agents for the initial 15-hour postoperative period. Surgical procedures included exploratory laparotomy, laryngotracheoplasty, and craniofacial reconstruction. As with narcotics administered by any route, intrathecal morphine can cause respiratory depression, and such depression may be delayed for up to 24 hours after the dose. Therefore, the postoperative respiratory status of these children should be monitored for 24 hours after the dose, preferably in an intensive care unit. With this caveat, the use of intrathecal morphine provides safe and effective postoperative analgesia in children undergoing major surgery.

Preanesthetic Medication of Children with Midazolam Using the Biojector Jet Injector

Background A rapid, dependable, and economical technique to atraumatically sedate children before anesthesia that does not prolong postanesthesia care unit time remains elusive. The Biojector jet injection system uses carbon dioxide rather than a needle to deliver an intramuscular injection. The dose-response relationship when midazolam is administered was studied using this jet injector.

Perioperative management issues in pediatric patients.

Recent developments in perioperative practice, emphasizing issues that are of greatest concern in pediatric patients, are reviewed in this article. Many areas bear further evaluation in the evolving field of perioperative medicine: Effective techniques of psychologic preparation for children and their parents in an era in which the family rarely encounters the hospital environment before the day of surgery Application of newer intraoperative anesthetics, such as new narcotics and muscle relaxants, to shorten PACU and pediatric ICU stay while maintaining safety and comfort Critical evaluation of current methods of pain management to optimize comfort, while minimizing cost of such management in an increasingly cost-conscious health care environment The recent advent of a process for credentialing pediatric anesthesia fellowship programs, which requires a research component, bodes well for the prospect of finding answers to some of these questions.

Monitoring the Resuscitation of Preterm Infants in the Delivery Room Using Pulse Oximetry

The first few minutes after birth are a critical time of adaptation of the newborn infant to extrauterine life. The adequacy of that adaptation has been evaluated by means of the summed Apgar score. In preterm infants, Apgar score may correlate less with adequacy of cardiopulmonary function because of developmental immaturity. Measurement of arterial oxygen saturation by means of pulse oximetry offers a physiologic, real time method of monitoring the progress of cardiopulmonary adaptation by which the clinician can evaluate the need for and success of resuscitative efforts. Four preterm infants are reported in whom pulse oximetry was useful in assessing the changes in oxygen saturation during resuscitation.