B-type natriuretic peptide: perioperative patterns in congenital heart disease.

OBJECTIVE: B-type natriuretic peptide (BNP) has diagnostic, prognostic, and therapeutic roles in adults with heart failure. BNP levels in children undergoing surgical repair of congenital heart disease (CHD) were characterized broadly, and distinguishable subgroup patterns delineated. DESIGN: Prospective, blinded, observational case series. SETTING: Academic, tertiary care, free-standing pediatric hospital. PATIENTS: Children with CHD; controls without cardiopulmonary disease. Interventions. None. MEASUREMENTS: Preoperative cardiac medications/doses, CHD lesion types, perioperative BNP levels, intraoperative variables (lengths of surgery, bypass, cross-clamp), postoperative outcomes (lengths of ventilation, hospitalization, open chest; averages of inotropic support, central venous pressure, perfusion, urine output; death, low cardiac output syndrome (LCOS), cardiac arrest; readmission; and discharge medications). RESULTS: Median BNP levels for 102 neonatal and non-neonatal controls were 27 and 7 pg/mL, respectively. Serial BNP measures from 105 patients undergoing CHD repair demonstrated a median postoperative peak at 12 hours. The median and interquartile postoperative 24-hour average BNP levels for neonates were 1506 (782-3784) pg/mL vs. 286 (169-578) pg/mL for non-neonates (P < 0.001). Postoperative BNP correlated with inotropic requirement, durations of open chest, ventilation, intensive care unit stay, and hospitalization (r = 0.33-0.65, all P < 0.001). Compared with biventricular CHD, Fontan palliations demonstrated lower postoperative BNP (median 150 vs. 306 pg/mL, P < 0.001), a 3-fold higher incidence of LCOS (P < 0.01), and longer length of hospitalization (median 6.0 vs. 4.5 days, P= 0.01). CONCLUSIONS: Perioperative BNP correlates to severity of illness and lengths of therapy in the CHD population, overall. Substantial variation in BNP across time as well as within and between CHD lesions limits its practical utility as an isolated point-of-care measure. BNP commonly peaks 6-12 hours postoperatively, but the timing and magnitude of BNP elevation demonstrates notable age-dependency, peaking earlier and rising an order of magnitude higher in neonates. In spite of higher clinical acuity, non-neonatal univentricular CHD paradoxically demonstrates lower BNP levels compared with biventricular physiologies.

Pharmacokinetics of dexmedetomidine in postsurgical pediatric intensive care unit patients: preliminary study.

OBJECTIVE: To characterize the pharmacokinetics of dexmedetomidine and monitor any dexmedetomidine-related adverse events in postoperative pediatric patients requiring short-term mechanical ventilation, analgesia, and sedation in the pediatric intensive care unit (PICU). DESIGN: Prospective, case series. SETTING: Operating room and PICU in a large, urban children's hospital. Enrollment from February 14 to November 25, 2002. PATIENTS: Ten children (4 months to 7.9 yrs of age) who received postoperative infusions of dexmedetomidine. INTERVENTIONS: Toward the end of the operation, patients received dexmedetomidine at 1 microg/kg per hr for 10 mins. The anesthesiologist then titrated the infusion, as clinically indicated, to a rate of 0.2-0.7 microg/kg per hr. In the PICU, the infusion was titrated by the nursing staff based on assessment with a modified Ramsey Sedation Scale, while maintaining heart rate and blood pressure within normal limits for age. Dexmedetomidine was continued until the intensivist felt the patient no longer benefited, but for no longer than 24 hrs. MEASUREMENTS AND MAIN RESULTS: At specified times during the infusion and after discontinuation, dexmedetomidine plasma concentrations were determined. Pharmacokinetic parameters were calculated using a two-compartment model. Vital signs, sedation scores, adjunct sedative or analgesic medications, and adverse events were recorded. Average duration of infusion was 18.8 hrs (range, 8-24 hrs). Means (+/-sd) were calculated for the following: clearance, 0.57 (+/-0.14) L/hr per kg; volume of distribution at steady state, 1.53 (+/-0.37) L/kg; and terminal elimination half-life, 2.65 (+/-0.88 hrs)-all similar to published values in adults. There were no serious adverse events related to dexmedetomidine. CONCLUSIONS: Dexmedetomidine, administered as a continuous infusion, produces consistent, predictable concentrations in children and infants. Further evaluations of the safety, efficacy, and pharmacodynamics of dexmedetomidine are warranted.

Blunt bowel and mesenteric injuries in children: Do nonspecific computed tomography findings reliably identify these injuries?

OBJECTIVE: Abdominal computed tomography has proven accurate for the detection of pediatric solid organ injuries following blunt abdominal trauma but is less reliable in detecting blunt bowel and mesenteric injuries (BBMI). The purpose of this study was to determine the significance of nonspecific findings on abdominal computed tomography (CT) scan in children at risk for BBMI. DESIGN: Retrospective chart review. SETTING: Regional pediatric trauma center. PATIENTS: All patients who received an abdominal CT scan as part of their evaluation following blunt abdominal trauma over a 10-yr period (September 1991 to September 2001). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Individual records were reviewed by one of the authors and analyzed for age, gender, mechanism of injury, diagnostic studies and procedures, results of initial CT scan, treatment, surgical procedures, complications, and outcome. Patients were excluded if they suffered penetrating trauma, had an abdominal CT scan performed at another institution, had a surgical procedure before CT scan, or had incomplete records. A total of 2,114 patients met inclusion criteria. Sixty-five percent were male and ages ranged from 3 wks to 18 yrs. There were 178 patients who had at least one nonspecific finding on abdominal CT scan suggestive of BBMI; 151 patients had one finding, 24 patients had two findings, and three had three findings. The risk of BBMI increased with the number of nonspecific findings (positive predictive value = 11% with at least one finding and 44% with two or more findings). This increase in positive predictive value, however, was accompanied by a reduction in sensitivity (62% and 37%, respectively). A total of 32 patients had surgically proven BBMI. Of these, eight had a single nonspecific finding on CT scan, ten had two findings, and two had three findings (12 patients had no CT findings suggestive of BBMI). There were complications in four of the 32 patients with BBMI and one death (due to laceration of the superior mesenteric artery). The complications appeared to occur independent of the time to surgical intervention. CONCLUSIONS: The presence of multiple nonspecific findings on abdominal CT scan does not reliably predict BBMI in children. Children also appear to suffer complications from BBMI less frequently than adults, regardless of the time to surgery. Therefore, nonspecific findings alone do not warrant surgical exploration. The decision to operate should instead be based on clinical data that include serial physical examinations.

Antipyretic efficacy and tolerability of a single intravenous dose of the acetaminophen prodrug propacetamol in children: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Propacetamol is an acetaminophen prodrug that was available in Europe as an IV formu lation for the treatment of pain and fever for some time. One gram of propacetamol is hydrolyzed in blood to release 0.5 g of acetaminophen and pharmacologically inactive N,N-diethylglycine. OBJECTIVE: This study compared the antipyretic efficacy and tolerability of IV propacetamol and placebo after a single administration in children with acute fever of infectious origin. The study was performed in anticipation of an application for US registration. METHODS: This was a double-blind, placebo-controlled trial in which patients with a body temperature (tympanic probe) of 38.5 degrees C to 41 degrees C were randomized to receive propacetamol 30 mg/kg IV or a placebo of identical appearance, both administered as 15-minute infusions. Temperature was measured at baseline, 0.5 hour after drug administration, and hourly thereafter for 6 hours or until use of rescue medication. The primary efficacy variable was the change in body temperature at each evaluation time compared with baseline. Secondary efficacy variables included the number of children requiring rescue medication and the time to remedication; the number of children with a body temperature <38 degrees C during the evaluation period and the time to reach this temperature; maximal body temperature reduction; and the weighted sum of changes in body temperature over the evaluation period. Tolerability was assessed based on changes in vital signs, monitored for 6 hours after administration of study drug, and adverse events recorded during the 24 hours after administration. RESULTS: Twenty children received propacetamol and 21 received placebo. Twenty patients were white, 17 black, and 4 Hispanic; their age ranged from 3 to 12 years. The actual mean (SD) dose of propacetamol received was 25.5 (0.6) mg/kg (equivalent to acetaminophen 12.8 [0.3] mg/kg). The reduction in body temperature was significantly greater in the propacetamol group compared with the placebo group at each time point over the 6-hour follow-up period (P < 0.001). Rescue medication was administered to 10.0% of patients in the propacetamol group, compared with 52.4% of those in the placebo group (P = 0.004). The weighted mean (SD) sum of the change in body temperature indicated greater antipyretic efficacy for propacetamol compared with placebo (-7.9 [3.8] degrees C x h vs 0.1 [3.6] degrees C x h, respectively; P < 0.001). There was no difference in the number of patients with treatment-emergent adverse events in the propacetamol and placebo groups (8 [40.0%] and 8 [38.1%]). The incidence of IV-site reactions was 10.0% in the propacetamol group and 9.5% in the placebo group. CONCLUSIONS: In these 41 children with acute fever of infectious origin, a propacetamol dose of 25.5 (0.6) mg/kg IV had significantly greater antipyretic efficacy than placebo and was equally well tolerated. Comparisons of this preparation with other IV antipyretic medications are needed.

Loss of consciousness: when to perform computed tomography?

OBJECTIVE: To determine the diagnostic value of physical examination (including neurologic exam) for positive computed tomography scan findings in children with closed head injury, Glasgow Coma Scale score 13-15 in the emergency department, and loss of consciousness or amnesia. DESIGN: Prospective descriptive study. SETTING: A large, tertiary, pediatric trauma center in San Diego County. PATIENTS: Children ages 2-16 with an isolated closed head injury, history of loss of consciousness or amnesia, and Glasgow Coma Scale 13-15 who were referred for pediatric trauma evaluation and received a head computed tomography as part of this evaluation. INTERVENTIONS: A standardized physical examination including skull/scalp exam, pupils, tympanic membrane, and brief neurologic exam was documented on each patient. MEASUREMENTS AND MAIN RESULTS: Subjects age 2-16 being evaluated by the pediatric trauma team for closed head injury with loss of consciousness or amnesia and Glasgow Coma Scale 13-15 received a standardized physical exam, noncontrast head computed tomography scan, and follow-up telephone call at 4-6 wks. Outcome variables include intracranial injury visualized on computed tomography scan and need for neurosurgical intervention. Ninety-eight subjects were enrolled in the study over a 1-yr period. Computed tomography scans revealed evidence of intracranial injury in 13 of 98 subjects (13%). Normal examination increased the probability of a normal computed tomography scan from.87 pretest to.90 posttest. Four of 38 subjects with normal examination were noted to have evidence of intracranial injury on computed tomography. These four subjects did not require neurosurgical intervention. Two of 98 subjects underwent neurosurgical procedures. One intracranial pressure monitor was placed for decreasing level of consciousness. One subject underwent surgical elevation of a depressed skull fracture. CONCLUSIONS: Detailed clinical examination is of no diagnostic value in detecting intracranial injuries found on head computed tomography scan. Patients with observed loss of consciousness or amnesia and Glasgow Coma Scale 13-15 should have a head computed tomography scan as part of their evaluation to avoid missing an intracranial injury.

The self-inflating bulb as an airway adjunct: is it reliable in children weighing less than 20 kilograms?

OBJECTIVES: To confirm the ability of the self-inflating bulb to indicate endotracheal tube (ETT) position in children weighing less than 20 kilograms, and to determine whether the presence of air in the stomach affects the bulb's accuracy. METHODS: This single-blind, prospective, single-cohort, repeated-measures, equivalence study was conducted in the operating room of a children's hospital. Seventy patients weighing less than 20 kilograms were enrolled. All patients had an uncuffed ETT placed in both the trachea and the esophagus. Measurements were initially obtained on both tubes without the presence of air in the stomach using the on-deflate method (the bulb is compressed after attachment to the ETT). Five mL/kg of air was then insufflated into the stomach and two additional measurements were obtained on each patient. The order in which the bulb was checked was determined by a computer-generated permuted block randomization scheme. The blinded assessor told the anesthesiologist when to start and stop the clock after each intervention. Five seconds was used as the cutoff time for which the clock was stopped. If the bulb re-expanded within 5 seconds, then the tube was considered to be in the trachea; if it did not re-expand, then this was considered to be an esophageal intubation. RESULTS: Median patient age was 2 years. The on-deflate method without air in the stomach had a sensitivity of 100% and a specificity of 94% for detecting tracheal intubations. With air in the stomach, the bulb had a sensitivity of 97% and a specificity of 96% (95% confidence interval [95% CI] for the difference between methods: sensitivity -3 to 10; specificity -10 to 7). The inaccuracy rate for the on-deflate method without air in the stomach was 3%, whereas the inaccuracy rate with air in the stomach was 4% (Delta -1, 95% CI = -5 to 4). There were no false positives or false negatives in the 24 patients weighing between 5 and 10 kilograms. CONCLUSIONS: The self-inflating bulb is a reliable method of detecting endotracheal tube position in children weighing less than 20 kg, even with the use of uncuffed endotracheal tubes. Furthermore, the presence of air in the stomach, simulating field conditions, does not affect bulb effectiveness in detecting endotracheal tube position.

The self-inflating bulb as an esophageal detector device in children weighing more than twenty kilograms: a comparison of two techniques.

STUDY OBJECTIVES: We confirm the ability of the self-inflating bulb to indicate endotracheal tube position in children and determine which method of bulb compression is more accurate. METHODS: This single-blind, prospective, single cohort, repeated measures comparison of the on-deflate and the off-deflate methods of bulb compression was conducted in the operating room of a children's hospital. Seventy-five patients weighing more than 20 kg were enrolled. All patients had an endotracheal tube placed in both the trachea and the esophagus, 5 mL/kg of air was insufflated into the stomach, and 4 measurements were obtained on each patient. The bulb was either applied to the endotracheal tube and then compressed (on-deflate method), or compressed before its attachment to the endotracheal tube (off-deflate method). The order in which the methods were utilized was determined by a computer-generated permuted block randomization scheme. The blinded assessor told the anesthesiologist when to start and stop the clock after each intervention. Five seconds was used as the cut-off time for which the clock was stopped. If the bulb reexpanded within 5 seconds, then the tube was considered to be in the trachea; if it did not reexpand, then this was considered to be an esophageal intubation. RESULTS: The mean patient age was 11 years. The on-deflate method had a sensitivity of 99% and a specificity of 92% for detecting tracheal intubations. The off-deflate method had a sensitivity of 99% and a specificity of 100% (95% confidence interval [CI] for the difference between methods: sensitivity -6 to 6, specificity -14 to 0.4). The inaccuracy rate for the off-deflate method was 1%, whereas the inaccuracy rate for the on-deflate method was 5% (Delta4; 95% CI 0.2 to 9). CONCLUSION: The self-inflating bulb is a reliable method of detecting endotracheal tube position in children. Furthermore, the off-deflate method may be more reliable and accurate than the on-deflate method when used in children weighing more than 20 kg.