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Biomedical subjects

D D Vernon

Publications and source records attributed to D D Vernon.

At least 19 recordsLinked to original sources
PubMed1996

Inhaled nitric oxide in children with severe lung disease: results of acute and prolonged therapy with two concentrations.

OBJECTIVES: To evaluate the acute effects of 11 and 60 parts per million (ppm) inhaled nitric oxide on the pulmonary vascular resistance and systemic oxygenation of children with severe lung disease, and to compare the outcome of prolonged therapy with approximately 10 and 40 ppm inhaled nitric oxide. DESIGN: Prospective, randomized study. SETTING: A 26-bed pediatric intensive care unit in a tertiary children's hospital. PATIENTS: Nineteen patients (median age 11 yrs, range 7 months to 16 yrs) with acute bilateral lung disease requiring a positive end-expiratory pressure (PEEP) of > 6 cm H2O and an FIO2 of > 0.5 for > 12 hrs were treated with inhaled nitric oxide. One patient was treated twice during the same hospitalization. INTERVENTIONS: Acute hemodynamic and blood gas effects of 11 and 60 ppm inhaled nitric oxide were studied, while delivering these concentrations in random order for intervals of 20 to 30 mins. Each interval was preceded by an interval of 20 to 30 mins without nitric oxide. Patients were then randomized and treated for a prolonged period with approximately 10 or 40 ppm inhaled nitric oxide independent of their initial acute responses to 11 and 60 ppm. Nitric oxide was discontinued when ventilatory support was decreased to a PEEP of < or = 6 cm H2O and an FIO2 of < or = 0.5. MEASUREMENTS AND MAIN RESULTS: Inhaled nitric oxide selectively decreased pulmonary vascular resistance and improved systemic oxygenation. Acute hemodynamic and blood gas effects of 11 and 60 ppm nitric oxide were similar. Systemic oxygenation improved to a greater extent in patients with radiographic evidence of residual aerated lung regions than in patients with diffuse bilateral lung disease. Maximum methemoglobin concentrations were greater in patients treated for a prolonged period with 40 ppm nitric oxide. The mortality and duration of therapy were similar for patients treated with 10 and 40 ppm inhaled nitric oxide. CONCLUSIONS: Pulmonary vascular resistance and systemic oxygenation are acutely improved to a similar extent by 11 and 60 ppm inhaled nitric oxide, and concentrations in excess of 10 ppm are probably not needed for prolonged therapy of children with severe lung disease.

Administration, Inhalation↗
PubMed1996

Fatal air bag mediated craniocervical trauma in a child.

This case report describes a 5-year-old child who sustained fatal craniocervical injuries as the result of an inflating automobile air bag. Although air bags have in general been shown to reduce the severity of injury to occupants of vehicles involved in front-end collisions, a growing number of incidents suggests that in some instances the air bag system itself may cause injuries, some of which can be serious or even fatal. Small children and infants in infant seats travelling in the front passenger seat appear to be particularly at risk. The increasing number of reports of air bag mediated injuries highlights the need for changes in both system design and possibly the threshold speed required for air bag deployment.

Air Bags↗
PubMed1996

Hemodynamic effects of N-acetylamrinone in a porcine model of group B streptococcal sepsis.

High plasma concentrations of N-acetylamrinone, a primary metabolite of amrinone, are measured in some children during prolonged amrinone infusion. The purpose of this investigation was to determine if N-acetylamrinone has direct hemodynamic effects independent of amrinone. Twenty neonatal piglets received an infusion of 6 x 10(9) colony-forming units/kg of group B Streptococcus to induce sepsis. Subsequently, they were divided into 1 of 3 groups and received a 1-hr infusion of either normal saline (N = 4); 8 mg/kg amrinone, followed by 20 micrograms/kg/min (N = 9); or 8 mg/kg N-acetylamrinone, followed by 20 micrograms/kg/min (N = 7). Hemodynamic measurements and arterial/venous blood-gas determinations were obtained every 30 min during the study. Systemic vascular resistance and pulmonary vascular resistance were calculated. One milliliter of blood was obtained every 30 min during drug administration to determine plasma amrinone and N-acetylamrinone concentrations. The mean amrinone plasma concentrations measured at 30 and 60 min during the infusion time in the group receiving amrinone were 8.8 +/- 1.1 and 6.9 +/- 0.7 micrograms/ml, respectively. These animals experienced a significant decrease in mean pulmonary artery pressure and pulmonary vascular resistance, compared with saline controls after a 30-min infusion of amrinone. The mean N-acetylamrinone plasma concentrations measured at 30 and 60 min during the N-acetylamrinone infusion were 7.3 +/- 0.8 and 5.7 +/- 0.6 micrograms/ml, respectively. There was no difference between any hemodynamic parameter measured in these animals, compared with saline controls at any time during the infusion. We conclude that amrinone, but not N-acetylamrinone, causes pulmonary vasodilation in a porcine model of sepsis and that the parent drug is the sole active component in amrinone.

Amrinone↗
PubMed1994

Advances in the critical care of poisoned paediatric patients.

Recent improvements in paediatric intensive care may potentially improve outcome for severely poisoned children. The application of advanced techniques of critical care to the poisoned paediatric patient encompasses a wide variety of therapeutic and technical innovations that are primarily directed towards support of the cardiopulmonary system and removal of toxins. New extracorporeal removal techniques such as continuous arterio-venous haemofiltration have not substantively increased our ability to remove toxins except in rare instances. Exotic techniques such as extracorporeal membrane oxygenation remain in the background for use in rare instances only, with little clear data on the relative risks and benefits of applying them.

Chelation Therapy↗
PubMed1994

Capillary refill.

Explore the source record for details and available documents.

Blood Circulation↗
PubMed1993

Modes of death in the pediatric intensive care unit: withdrawal and limitation of supportive care.

OBJECTIVE: To determine the frequency of withdrawal or limitation of supportive care for children dying in a pediatric intensive care unit (ICU). DESIGN: Retrospective review of medical records. SETTING: Pediatric ICU in a tertiary care children's hospital. PATIENTS: All children dying in the pediatric ICU over a 54-month period (n = 300). INTERVENTIONS: Medical record review. MEASUREMENTS AND MAIN RESULTS: Data recorded for each patient included diagnosis, mode of death, and whether the child was brain dead. Each patient was assigned to one of the following mode of death categories: brain dead; active withdrawal of supportive care (meaning removal of the endotracheal tube); failed cardiopulmonary resuscitation; allowed to die without cardiopulmonary resuscitation (do-not-resuscitate status). A total of 300 patients were identified. Diagnoses included postoperative congenital heart disease (n = 56), head trauma (n = 38), near-miss sudden infant death syndrome (n = 28), pneumonia (n = 22), sepsis (n = 21), near-drowning (n = 21), various anoxic insults (n = 20), multiple trauma (n = 17), and patients with other diagnoses (n = 77). Mode of death was active discontinuation of support in 95 (32%) patients, do-not-resuscitate status in 78 (26%), brain death in 70 (23%), and failed cardiopulmonary resuscitation in 57 (19%). CONCLUSIONS: In a large, multidisciplinary pediatric ICU, the most common mode of death was active withdrawal of support. In addition, more than half (173/300, 58%) of children dying in the pediatric ICU underwent either active withdrawal or limitation (do-not-resuscitate status) of supportive care.

Brain Death↗
PubMed1992

Hemodynamic effects of dobutamine in an intact animal model.

BACKGROUND AND METHODS: Actions of dobutamine at the beta 1, beta 2, and alpha 1 adrenoreceptors were studied in anesthetized dogs. Six animals received dobutamine (at infusion rates of 0 to 160 micrograms/kg/min) with and without beta-adrenergic receptor blockade. Five animals received phenylephrine (0 to 16 micrograms/kg/min), with and without concurrent dobutamine (20 micrograms/kg/min); this procedure was repeated in five animals after beta-blockade. RESULTS: Dobutamine (10 to 160 micrograms/kg/min) increased heart rate (HR), cardiac output, and left ventricular change in pressure over time, and decreased systemic vascular resistance. beta-blockade prevented only dobutamine-induced changes in HR. Mean arterial pressure (MAP), unaffected by dobutamine alone, decreased with concurrent beta-blockade. Phenylephrine (1 to 16 micrograms/kg/min)-induced increases in MAP were unaffected by dobutamine; with beta-blockade, phenylephrine reduced MAP. Dobutamine prevented a phenylephrine-induced increase in systemic vascular resistance, an effect eliminated by beta-adrenergic receptor blockade. CONCLUSIONS: Dobutamine appeared to be an agonist at the beta 1- and beta 2-adrenoreceptors and at the myocardial alpha-adrenoreceptor. Dobutamine appeared to be an alpha-adrenergic receptor antagonist in the peripheral vasculature.

Adrenergic beta-Antagonists↗
PubMed1992

Management of the patient with head injury during transport.

The most important principles of initial management of the head-injured patient are rapid transport to an institution capable of providing the sophisticated evaluation, neurosurgical services, and monitoring necessary to improve outcome because definitive management of the head-injured patient is not possible in the field. The emphasis of care during stabilization and transport should be on the prevention of secondary central nervous system injury, primarily by prompt stabilization of the airway and assurance of proper ventilation and oxygenation, and by control of bleeding and provision of adequate circulation.

Craniocerebral Trauma↗
PubMed1991

Mortality rates and prognostic variables in children with adult respiratory distress syndrome.

In a retrospective chart review of cases of adult respiratory distress syndrome in our pediatric intensive care unit from 1987 to 1990, we attempted to identify the physiologic variables predictive of death. We identified 44 children with adult respiratory distress syndrome; the mortality rate was 75%. We found significant differences between survivors and nonsurvivors in intrapulmonary venous admixture (Qsp/Qt), mean airway pressure (Paw), alveolar-arterial oxygen tension difference (P(A-a)O2), oxygenation index, and peak inspirator pressure; Qsp/Qt greater than 0.5, Paw greater than 23 cm H2O, and P(A-a)O2 greater than 470 mm Hg were 93%, 90%, and 81% predictive of death, respectively, in this study population. Sensitivity and specificity were enhanced when we linked multiple predictors, but this linkage was seldom successful because few patients had more than one positive predictor. We propose to use the individual predictors that we have identified as randomization criteria in a future trial of extracorporeal membrane oxygenation for pediatric cases of adult respiratory distress syndrome.

Adolescent↗
PubMed1991

Efficacy of dopamine and norepinephrine for treatment of hemodynamic compromise in amitriptyline intoxication.

BACKGROUND AND METHODS: Dopamine and norepinephrine were evaluated for treatment of hemodynamic compromise in amitriptyline intoxication. Fifteen anesthetized dogs underwent hemodynamic monitoring and amitriptyline intoxication, and received three infusion rates of dopamine (5, 15, and 30 micrograms/kg.min) and three infusion rates of norepinephrine (0.25, 0.5, and 1.0 micrograms/kg.min), sequentially, with hemodynamic measurements at each dose. Data were analyzed using repeated-measures analysis of variance; p less than .05 was considered significant. RESULTS: Amitriptyline intoxication lowered cardiac output, peak left ventricular dP/dt, and mean arterial pressure (MAP). All doses of norepinephrine and the two higher doses of dopamine increased cardiac output, MAP, and peak left ventricular dP/dt during the intoxicated state. Both agents restored all variables to preintoxication values. Values obtained at the highest doses of the two drugs were not different for any variable. CONCLUSION: Dopamine and norepinephrine each appeared effective in reversing amitriptyline-induced hemodynamic alterations.

Amitriptyline↗
PubMed1991

Nonlinear dobutamine pharmacokinetics in a pediatric population.

OBJECTIVE: To evaluate a linear kinetic model for dobutamine clearance. DESIGN: A prospective evaluation of pediatric patients receiving continuous infusions of dobutamine at varying doses. SETTING: A pediatric critical care unit. PATIENTS: Twelve patients age 2 days to 9 yrs and weighing 2.7 to 33 kg who required vasopressor therapy. Infusion rates for dobutamine ranged from 2 to 15 micrograms/kg.min. MEASUREMENTS AND MAIN RESULTS: Serum concentrations varied from 6.4 to 347 ng/mL (21 to 1151 nmol/L). Concentration was found to increase with dose. However, the relationship of clearance to steady-state concentration had a negative slope. Values for clearance varied from 32 to 625 mL/kg.min. Multiple analysis of variance on age, weight, and co-infused dopamine showed that these factors did not influence the relationship of clearance to steady-state concentration. Analysis to show an underlying model failed to differentiate Michaelis-Menten from nonlinear binding or mixed models on the basis of these data. CONCLUSIONS: Dobutamine pharmacokinetics do not appear to follow a simple linear model. Based on the current data, neither age nor the added infusion of dopamine affects the clearance of dobutamine.

Age Factors↗
PubMed1991

Skin necrosis complicating intraosseous infusion.

Bone marrow infusion is currently recommended as a useful technique for rapidly obtaining vascular access in critically ill children. Minor complications occur frequently, but serious complications of this technique are uncommon. We describe two patients with local skin necrosis complicating intraosseous infusion. To minimize the complications of this technique, we recommend placement verification before fluid infusion, careful monitoring for infiltration, and prompt removal after venous access is obtained.

Bone Marrow↗
PubMed1990

Failure of CAVH to remove digoxin-Fab complex in piglets.

Digoxin toxicity may be associated with renal failure and an inability to excrete the digoxin-Fab (antibody fragment) complex used in detoxification. We are unaware of any previous reports regarding the removal of digoxin-Fab fragment complex by continuous arteriovenous hemofiltration. Continuous arteriovenous hemofiltration allows ultrafiltration of molecules less than 50,000 daltons. Because the digoxin-Fab fragment complex has a molecular weight of 45 - 50,000 daltons, we evaluated the efficiency of continuous arteriovenous hemofiltration in removing the digoxin-Fab fragment complex. Three piglets were given 100 mcg/kg digoxin IM, in divided doses. Animals were anesthetized and continuous arteriovenous hemofiltration was begun using a Diafilter 10 cartridge. A mean ultrafiltration rate of 3.6 +/- 0.4 ml/min was obtained. The system equilibrated for 30 minutes and initial serum and ultrafiltrate digoxin levels were obtained. Mean serum values were total 6.20 +/- 1.74 ng/ml and free 3.72 +/- 0.88 ng/ml. Digibind 40 mg IV was given and then samples of serum and ultrafiltrate were obtained at 30, 60 and 90 minutes for digoxin levels. Mean values were as follows: 30 min serum total 54.23 +/- 26.13 ng/ml and free 0.08 +/- 0.08 ng/ml; 60 min serum total 61.24 +/- 27.31 ng/ml and free 0.07 +/- 0.04 ng/ml; and 90 min serum total 67.63 +/- 26.78 ng/ml and free 0.10 +/- 0.10 ng/ml. Ultrafiltrate levels throughout the experiment were negligible (less than or equal to 0.04 ng/ml). Continuous arteriovenous hemofiltration appears to be ineffective in removing the digoxin-Fab fragment complex.

Animals↗