Stephen Rimar

INHALED NITRIC OXIDE AND PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN

Background Persistent pulmonary hypertension of the newborn causes systemic arterial hypoxemia because of increased pulmonary vascular resistance and right-to-left shunting of deoxygenated blood. Inhaled nitric oxide decreases pulmonary vascular resistance in newborns. We studied whether inhaled nitric oxide decreases severe hypoxemia in infants with persistent pulmonary hypertension. Methods In a prospective, multicenter study, 58 full-term infants with severe hypoxemia and persistent pulmonary hypertension were randomly assigned to breathe either a control gas (nitrogen) or nitric oxide (80 parts per million), mixed with oxygen from a ventilator. If oxygenation increased after 20 minutes and systemic blood pressure did not decrease, the treatment was considered successful and was continued at lower concentrations. Otherwise, it was discontinued and alternative therapies, including extracorporeal membrane oxygenation, were used. Results Inhaled nitric oxide successfully doubled systemic oxygenation in 16 of 30 infants (53 percent), whereas conventional therapy without inhaled nitric oxide increased oxygenation in only 2 of 28 infants (7 percent). Long-term therapy with inhaled nitric oxide sustained systemic oxygenation in 75 percent of the infants who had initial improvement. Extracorporeal membrane oxygenation was required in 71 percent of the control group and 40 percent of the nitric oxide group (P=0.02). The number of deaths was similar in the two groups. Inhaled nitric oxide did not cause systemic hypotension or increase methemoglobin levels. Conclusions Inhaled nitric oxide improves systemic oxygenation in infants with persistent pulmonary hypertension and may reduce the need for more invasive treatments.

Parental presence during induction of anesthesia. A randomized controlled trial

Background To determine whether parental presence during induction of anesthesia is an effective preoperative behavioral intervention, a randomized controlled trial with children undergoing outpatient surgery was conducted. Methods Eighty-four children were randomly assigned to a parent-present or parent-absent group. Using multiple behavioral and physiologic measures of anxiety, the effect of the intervention on the children and their parents was assessed. Predictors for the response to the intervention were examined using multivariate linear regression analysis. Results When the intervention group (parent-present) was compared to the control group (parent-absent), overall there were no significant differences in any of the behavioral or physiologic measures of anxiety tested during induction of anesthesia. Using the childs serum cortisol concentration as the outcome, parental presence, the childs age and baseline temperament, and trait anxiety of the parent, were identified as predictors of the childs anxiety during induction. Analysis of variance demonstrated that three groups showed diminished cortisol concentrations with parental presence: children older than 4 yr (P = 0.001), children whose parent had a low trait anxiety (P = 0.02), and children who had a low baseline level of activity as assessed by temperament (P = 0.05). Conclusions Children who were older than 4 yr or those with a parent with a low trait anxiety or who had a low baseline level of activity/temperament benefited from parental presence during induction.

Premedication in the United States: a status report.

We undertook a mailing survey study to assess the current practice of sedative premedication in anesthesia.A total of 5396 questionnaires were mailed to randomly selected physician members of the American Society of Anesthesiologists. Forty-six percent (n = 2421) of those sampled returned the questionnaire after two mailings. The reported rate of sedative premedication in the United States varied widely among age groups and geographical locations. Premedicant sedative drugs were least often used with children younger than age 3 years and most often used with adults less than 65 years of age (25% vs 75%, P = 0.001). Midazolam was the most frequently used premedicant both in adults and children (>75%). When analyzed based on geographical locations, use of sedative premedicants among adults was least frequent in the Northeast region and most frequent in the Southeast region (50% vs 90%, P = 0.001). When the frequency of premedication was examined against health maintenance organization (HMO) penetration (i.e., HMO enrollment by total population) in the various geographical regions, correlation coefficients (r) ranged from -0.96 to -0.54. Multivariable analysis revealed that HMO penetration is an independent predictor for the use of premedication in adults and children. The marked variation among geographical areas in premedicant usage patterns under-scores the lack of consensus among anesthesiologists about the need for premedication. The data suggest that HMO participation may affect delivery of this component of anesthetic care. (Anesth Analg 1997;84:427-32)

Measurement tool for preoperative anxiety in young children: The yale preoperative anxiety scale

Abstract To develop a preoperative anxiety scale (YPAS) for children undergoing surgery, 21 specific behaviors indicating anxiety were defined within five domains (activity, emotional expressivity, state of arousal, vocalization, and use of adults). A reliability Kappa analysis revealed that inter-observer agreement ranged from .66 to .94, while intra-observer Kappa ranged from .66 to .91. Validity analysis between a Visual Analog Scale and the YPAS revealed an r of .59 for entering the operating room. Multiserial analysis comparing the YPAS to the Vernon Anxiety Scale ranged from .61 to .64. Showing good to excellent observer reliability and validity, the YPAS proves to be an appropriate tool for studying childrens responses in preoperative settings. As such, the new assessment instrument should be of interest to clinical and research neuropsychologists who need to assess a childs anxiety level prior to the undertaking of a given surgical procedure.

A First-pass Cost Analysis of Propofol Versus Barbiturates for Children Undergoing Magnetic Resonance Imaging

Intravenous (IV) propofol was compared with IV thiopental/pentobarbital as a sedative for children undergoing magnetic resonance imaging (MRI) of the brain or spine. Fifty-eight outpatients (aged 11 mo to 6 1/2 yr, ASA grade I and II) were enrolled in the study and randomized to two groups. After IV cannulation, Group I received IV propofol (1-2 mg/kg), followed immediately by a propofol infusion (75-100 micrograms.kg-1.min-1). Group II received IV thiopental (1-3 mg/kg) followed by a pentobarbital bolus (2-3 mg/kg). Supplemental thiopental doses (1-2 mg/kg) were administrated to maintain adequate sedation. Discharge time and postanesthesia recovery scores were determined by an independent blinded observer. Time of recovery to full consciousness in Group I was significantly less than in Group II (19 +/- 7 min vs 35 +/- 20; P < 0.005). Time to discharge was also significantly less in Group I (24 +/- 6 min vs 40 +/- 11; P < 0.05). A preliminary cost analysis was applied to the clinical data obtained and to a theoretical model of a pediatric MRI center. Cost analysis of anesthesia services revealed added drug costs (

Single-Dose Ondansetron Prevents Postoperative Vomiting in Pediatric Outpatients

1600.76 per year for the propofol group) but significant savings of postanesthesia care unit (PACU) nursing time (

Cocaine abuse in the parturient and effects on the fetus and neonate.

5086.67 per year). Outcomes such as patient morbidity and technical quality of the MRI scans did not differ significantly between the two groups. In conclusion, analysis of the clinical data suggests that propofol may be more suitable than barbiturates for children undergoing outpatient procedures despite its higher price.

Establishment of a pediatric surgery center: increasing anesthetic efficiency

This randomized, double-blind, parallel-group, multicenter study evaluated the safety and efficacy of ondansetron (0.1 mg/kg to 4 mg intravenously) compared with placebo in the prevention of postoperative vomiting in 429 ASA status I-III children 1-12 yr old undergoing outpatient surgery under nitrous oxide- and halothane-based general anesthesia. The results show that during both the 2-h and the 24-h evaluation periods after discontinuation of nitrous oxide, a significantly greater percentage of ondansetron-treated patients (2 h 89%, 24 h 68%) compared with placebo-treated patients (2 h 71%, 24 h 40%) experienced complete response (i.e., no emetic episodes, not rescued, and not withdrawn; P < 0.001 at both time points). Ondansetron-treated patients reached criteria for home readiness one-half hour sooner than placebo-treated patients (P < 0.05). The age of the child, use of intraoperative opioids, type of surgery, and requirement to tolerate fluids before discharge may also have affected the incidence of postoperative emesis during the 0- to 24-h observation period. Use of postoperative opioids did not have any effect on complete response rates in this patient population. We conclude that the prophylactic use of ondansetron reduces postoperative emesis in pediatric patients, regardless of the operant influential factors. Implications: Postoperative nausea and vomiting often occur after surgery and general anesthesia in children and are the major reason for unexpected hospital admission after ambulatory surgery. Our study demonstrates that the prophylactic use of a small dose of ondansetron reduces postoperative vomiting in pediatric patients. (Anesth Analg 1997;85:538-45)

Analysis of Cost Savings in the Recovery Room Requires Complex Models

The growing use of cocaine among pregnant women and women of childbearing age has become an issue of great concern to physicians. Cocaine abuse among parturients is associated with multi-target organ involvement, including the cardiovascular, respiratory, neurologic, and hematologic systems. Cocaine use during pregnancy is also an independent contributor to the risk of placental abruption, preterm labor, precipitate delivery, stillbirth, and others. Although a history of premature rupture of membranes, smoking, alcohol use, syphilis serology, and use of other illicit drugs suggests cocaine abuse, the single most important predictor is the absence of prenatal care. The intraoperative anesthetic management should take into consideration the different effects of cocaine on the mother, the fetus, and the neonate.

Autonomic dysfunction, peripheral neuropathy, and depression

STUDY OBJECTIVE To examine whether the establishment of dedicated pediatric operating rooms (ORs) staffed exclusively by pediatric anesthesiologists has had a significant impact on anesthetic efficiency during surgery. STUDY DESIGN Before and after design. SETTING General and pediatric operating rooms at Yale-New Haven Hospital. MEASUREMENTS AND MAIN RESULTS Using Operating Room Information System data (1991 to 1997), we examined whether the anesthesia-controlled time, the time it takes for induction and emergence of anesthesia of a selected surgical procedure (tonsillectomy and adenoidectomy), was affected by the change of practice from general to pediatric ORs. The average length of anesthesia induction decreased by 30% (p = 0.0007). Similarly, the average length of emergence from anesthesia decreased by 42% (p = 0.01) and anesthesia-controlled time decreased by 31% (p = 0.0008). Of particular importance is the decrease by 75% in the anesthesia-controlled time range (maximum-minimum). CONCLUSIONS The establishment of dedicated pediatric ORs resulted in significantly shorter anesthesia induction and emergence times. Furthermore, the decreased variability of anesthesia-controlled time may allow for better scheduling of surgical cases and for better surgeon and patient satisfaction.