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Biomedical subjects

M J Heulitt

Publications and source records attributed to M J Heulitt.

9 recordsLinked to original sources
PubMed1997

Efficacy of metered-dose inhaler administration of albuterol in intubated infants.

STUDY OBJECTIVE: To compare the safety and efficacy of metered-dose inhaler (MDI) albuterol to nebulized (NEB) albuterol administration. DESIGN: A randomized, triple-blinded, crossover study. SETTING: A pediatric ICU in a tertiary care children's hospital. PATIENTS: Eleven intubated infants with bronchiolitis. INTERVENTIONS: Subjects received four puffs of MDI albuterol (360 microg) and 3 mL of NEB saline solution placebo or 0.3 mL of NEB albuterol (1.5 mg) and MDI saline solution placebo. Each set of albuterol and saline solution placebo was administered after direct attachment of delivery device to the endotracheal tube and bag-valve system. Subjects received the opposite sequence 4 h after the initial sequence. The second sequence was given first the next day, and the first sequence was administered 4 h later. MEASUREMENTS AND RESULTS: Respiratory system compliance and resistance were measured at baseline and 30 min, 1 h, 2 h, and 4 h after each set of placebo and albuterol. There was an appreciable improvement in compliance and resistance for up to 2 h following both methods of administration. However, the degree of improvement was not significantly different (p>0.05) between the two methods. Neither method caused a significant change in resistance when measured at 4 h after albuterol/placebo administration. No evidence of toxicity was detected. CONCLUSIONS: MDI-administered albuterol is as safe and efficacious as nebulized-administered albuterol in intubated infants with bronchiolitis. Generalizability of these results is limited by differences in drug delivery with different brands of nebulizers and spacers and sites of attachment.

Administration, Inhalation↗
PubMed1996

Comparison of total resistive work of breathing in two generations of ventilators in an animal model.

Spontaneous breathing through an endotracheal tube and ventilator circuit is associated with an increased work of breathing (WOB). Recently, pediatric ventilators have introduced improved features to optimize patient-ventilator interactions. We performed an experiment utilizing an animal model to compare total resistive WOB of two widely used ventilators, the Siemens Servo Ventilator 300 (SV300) with patient-optimized features, such as flow-triggering and rapid response time, and the Siemens 900C (S900C) without those features. A total of 120 experiments of 10 minutes duration each were performed in 6 anesthetized, intubated lambs. In each experiment, the animal was randomized to either pressure support ventilation (PSV) of 5 cm H2O, or continuous positive airway pressure (CPAP) with 0 cmH2O end expiratory pressure (ZEEP) while supported by the SV300 or the S900C. Each animal was used as its own control. WOB was measured with a Bicore monitoring device as WOB of the animal (WOBp), WOB of the ventilator (WOBv), and the pressure time product (PTP) for each breath during the experiment. Oxygen consumption (Vo2) of the animal was measured using breath-by-breath gas analysis with a customized metabolic monitoring system. A Wilcoxon signed rank sum test was used for analysis. All comparisons between the ventilators for both CPAP and PSV showed a statistically significant difference (p < 0.001). WOBp was reduced by 47% during pressure support ventilation (PSV) and by 47% during CPAP when the SV300 was used compared to the S900C. We conclude that WOB is significantly lower in animals ventilated with the SV300 than with the S900C ventilator, and we speculate that ventilators with the features of the SV300 may offer advantages in ventilating pediatric patients.

Airway Resistance↗
PubMed1996

Pharmacokinetics and pharmacodynamics of famotidine in children.

The pharmacokinetics and pharmacodynamics of intravenous famotidine were studied in 12 children (1.1-12.9 years of age; mean weight +/- standard deviation = 27.6 +/- 21.2 kg) who were given the drug for prophylactic management of stress ulceration. After a 0.5-mg/kg infusion of famotidine, timed blood (n = 10) and urine (n = 6) samples and repeated evaluations of intragastric pH (n = 13) were obtained from each subject. Pharmacokinetic parameters were determined from curve fitting of serum concentration data. The mean (+/- SD) maximum serum concentration (Cmax) was 527.6 +/- 281.2 ng/mL, the elimination half-life (t1/2) was 3.2 +/- 3.0 hours, and the apparent steady-state volume of distribution (Vdss) was 2.4 +/- 1.7 L/kg. Plasma clearance (Cl) and renal clearance (ClR) were 0.70 +/- 0.34 L/hr/kg and 0.43 +/- 0.24 L/hr/kg, respectively. Over 24 hours, 73.0 +/- 27.3% of the dose was excreted unchanged in the urine (Fel). Pharmacodynamic analysis of gastric pH data using the sigmoid Emax model predicted that 50% of the maximal effect of famotidine (EC50) occurs at a serum concentration of 26.0 +/- 13.2 ng/mL. Children who did not have an initial intragastric pH < or = 4 did not have a significant response in pH after receiving famotidine. Although Vdss and Cl were higher in these children than those seen in adults, statistically significant relationships between these parameters and age were not observed in the study population. The pharmacodynamics and pharmacokinetics of famotidine in children older than one year of age appear to be similar to those noted in adults.

Child↗
PubMed1995

Infections during extracorporeal life support.

Little data exist on the type of infections patients acquire during extracorporeal life support. Through a retrospective analysis of 109 patients who underwent 115 episodes of venoarterial extracorporeal life support, it was determined that nosocomial infections developed in 18 patients (16%). Patients with nosocomial infections were supported for longer periods of time (230 versus 140 hours; P < .05) and were more likely to have an open chest (P = .02) than those who did not have infectious complications. Blood-borne infections occurred most often while patients were cannulated for extracorporeal life support, with urinary tract and wound infections more commonly occurring after decannulation. Fungal organisms were isolated in 50% of nosocomial infections. Patients with blood or wound fungal infections had a higher case-fatality rate than those patients with bacterial complications (P = .03). Because it is unlikely that the duration of extracorporeal life support can be shortened significantly, the authors recommend an increased level of awareness of nosocomial infections in patients on prolonged extracorporeal life support. Further research is needed to assess the effects of antifungal prophylaxis or immune modulation to prevent nosocomial infections.

Adolescent↗
PubMed1995

Inter-hospital transport of neonatal patients on extracorporeal membrane oxygenation: mobile-ECMO.

OBJECTIVE: To describe the equipment, personnel requirements, training, management techniques, and logistic problems encountered in the design and implementation of a mobile extracorporeal membrane oxygenation (ECMO) program. DESIGN: This is a report of a technique for the transport of patients on ECMO and a description of our retrospective case series. SETTINGS: The study was conducted at a regional referral children's hospital and ECMO unit. PATIENTS: Thirteen neonatal medical patients with acute respiratory failure were transported with mobile-ECMO. RESULTS: Over a 24-month period, we transported 13 neonatal patients with mobile-ECMO. The reason for transport with mobile-ECMO was inability to convert from high-frequency ventilation (4 of 13), patient already on ECMO (1 of 13), and patient deemed too unstable for conventional transport (8 of 13). Eleven of the 13 patients were transported from other ECMO centers. Of the 13, 9 survived. No major complications during transport were reported for any of the patients. Follow-up data were available on all nine survivors of neonatal mobile-ECMO. Eight of these had normal magnetic resonance imaging scans of the brain; the ninth had a small hemorrhage in the left cerebellum. CONCLUSION: Our limited series shows that patients can be safely transported with mobile-ECMO. This program does not replace the early appropriate transfer for ECMO-eligible patients to an ECMO center.

Arkansas↗
PubMed1993

Flexible fiberoptic bronchoscopy in children on extracorporeal membrane oxygenation.

Bleeding is one of the most feared complications of veno-arterial (V-A) extracorporeal membrane oxygenation (ECMO), and is also a potential complication of flexible fiberoptic bronchoscopy (FFB). We retrospectively reviewed 14 patients who underwent FFB procedures with bronchial washings (BW) and bronchoalveolar lavage (BAL) to evaluate the safety of this procedure in children on ECMO. Standard FFB with BAL/BW technique was used after stabilization on ECMO. Three patients underwent two procedures each, and one patient underwent three, for a total of 19 procedures. No significant complications, such as bleeding have occurred. Three patients required additional ECMO support shortly after FFB. After the 16 procedures done for atelectasis, seven patients improved radiographically, three had increased opacifications, and six were unchanged. The remaining three patients had suspected pulmonary infections, and in each, therapeutic decisions were guided by the BAL results. Lung compliance was unchanged or improved after 11 of 13 procedures. We conclude that FFB with BAL/BW in children on ECMO is safe and may benefit certain patients.

Bronchoalveolar Lavage Fluid↗
PubMed1993

Double-blind, randomized, controlled trial of papaverine-containing infusions to prevent failure of arterial catheters in pediatric patients.

OBJECTIVE: To test the efficacy of the continuous infusion of papaverine-containing fluids into peripheral arterial catheters for reducing the risk of catheter failure. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Pediatric intensive care unit in a children's hospital. PATIENTS: A total of 239 children, aged 3 wks to 18 yrs who had an arterial catheter inserted for clinical purposes. INTERVENTIONS: Patients were randomized to receive either papaverine (60 mg/500 mL) or no additive, within the infused fluids. MEASUREMENTS AND MAIN RESULTS: Data about patient demographics and potential risk factors for arterial catheter failure were collected at the time of catheter insertion, throughout the life of the catheter, and at the time of catheter removal. Catheter failure was defined as an inability to draw blood from the catheter or loss of the arterial waveform. Overall, 35 (15%) subjects had catheter failure. The risk of catheter failure was lower in patients randomized to receive papaverine (eight [7%] of 115 vs. 27 [22%] of 124; chi-square = 5.2; p = .02), and the time until failure of the catheter was longer in the papaverine group (p = .02, log-rank test). This difference persisted when controlling for potentially confounding factors. CONCLUSION: In critically ill children, infusion of papaverine-containing fluids reduces the risk of failure of peripheral arterial catheters.

Adolescent↗
PubMed1988

Febrile infants less than 3 months old: value of chest radiography.

In the febrile infant less than 3 months old, a chest radiograph is commonly obtained to identify the cause of the fever. The purpose of this study was to evaluate the necessity of obtaining chest radiographs in this population. The clinical records and chest radiographs of 192 febrile infants (greater than 100.5 degrees F, rectal) were reviewed. Nineteen patients had signs of respiratory distress; seven had positive findings on chest radiographs. Of the 173 patients without signs of respiratory distress, five had positive findings on chest radiographs. When chest radiography was considered the gold standard for the presence or absence of pneumonia, findings of respiratory distress on physical examination had a sensitivity of 58% and a specificity of 93% for the detection of pneumonia. The prevalence of positive findings on chest radiographs in febrile infants less than 3 months old was 6%. A chest radiograph should be obtained in febrile infants only when signs of respiratory distress are present.

Female↗