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D Bohn

Publications and source records attributed to D Bohn.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effect of hypothermia on the pharmacokinetics of ethanol in piglets.

The effect of hypothermia (29 C) on the pharmacokinetics of ethanol was studied in eight piglets serving as their own normothermic controls. Ten milliliters of 12% ethanol per kilogram were infused over 30 minutes, and serum ethanol concentrations were measured for seven hours. Ethanol concentration data were fitted to one-compartment open model assuming Michaelis Menten elimination kinetics. During hypothermia, ethanol concentrations were consistently higher than during normothermia. This observation could be explained by both a significantly smaller distribution volume of ethanol during hypothermia (0.71 +/- 0.03 L/kg at 29 C and 0.84 +/- 0.05 L/kg at 37 C, P less than .02) and a significantly slower maximum velocity of metabolism of ethanol (Vm) during hypothermia (1.12 +/- 0.11 mg/kg.min vs. 1.83 +/- 0.21 mg/kg.min, P less than .01). Our study indicates that during hypothermia, ethanol stays significantly longer in the circulation in piglets. Potentially, this may contribute to a more profound effect from the ethanol.

Animals↗
PubMed1989

Evaluation of a new method of detection of nosocomial infection in the pediatric intensive care unit: the Infection Control Sentinel Sheet System.

To improve the efficiency of nosocomial infection detection, a highly structured system combining initial reporting by the bedside night nurse of symptoms possibly related to infection with follow-up by the infection control nurse (ICN) was developed: The Infection Control Sentinel Sheet System (ICSSS). Between July 1, 1987 and February 28, 1988, a prospective comparison of results obtained through ICSSS and daily bedside observation/chart review by a full-time trained intensivist was undertaken in the pediatric intensive care unit (PICU). Ratios of nosocomial infections and nosocomially-infected patients were 15.8 and 7.0 respectively among 685 admissions; included are seven infections identified only through the ICSSS so that the "gold standard" became an amalgamation of the two systems. The sensitivity for detection of nosocomially-infected patients by bedside observation/chart review and ICSSS was 100% and 87% respectively. The sensitivity for detection of standard infections (blood, wound and urine) was 88% and 85% respectively. The sensitivity for detection of nosocomial infections at all sites was 94% and 72% respectively. Missed infections were minor (e.g., drain, skin, eye), required physician diagnosis (e.g., pneumonia), were not requested on the sentinel sheet (SS) (e.g., otitis media), related to follow-up of deceased patients or were minor misclassifications or failures to associate with device (e.g., central-line related). Daily PICU surveillance by the ICN required only 20 minutes a day. The ICSSS appears highly promising and has many unmeasured benefits.

Bias↗
PubMed1989

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Dictionaries as Topic↗
PubMed1988

Intermittently occurring right-posterior slow waves (IRP) in psychiatric patients. An electroencephalographic indicator of cerebral dysfunction.

Intermittent right-posterior accentuated slow waves (irregular theta and/or delta waves: IRP phenomenon) in the EEG showed an incidence of about 5% in the total in-patients of a psychiatric university hospital. The IRP phenomenon was found in 7.5% of patients with schizophrenic psychoses, 2% of patients with affective psychoses and in 2.4% of patients with neurotic and personality disorders. The IRP groups differed from control groups in a number of sociobiographical and clinical characteristics. Having repeatedly confirmed these relationships with different samples, we regard IRP patients, irrespective of the diagnosis given, as having a maturational deficit of brain function.

Adolescent↗
PubMed1988

Successful use of intraaortic balloon pumping in a 2-kilogram infant.

Severe low cardiac output of unknown cause that did not respond to inotropic and ventilatory support developed in a 2-kg infant. Intraaortic balloon pumping was used successfully to acutely improve her cardiac function and peripheral perfusion and to decrease the requirement for inotropic medications. We describe the technique for insertion and the equipment used, as well as our experience with intraaortic balloon pumping in children.

Cardiac Output, Low↗
PubMed1987

The influence of hypothermia on the disposition of fentanyl--human and animal studies.

The effect of hypothermia on the disposition of fentanyl was evaluated in 18 children undergoing corrective cardiac surgery. They received a bolus of fentanyl followed by a continuous infusion which was stopped when cardiopulmonary bypass was established and profound hypothermia was achieved (18 degrees C-25 degrees C). Fentanyl plasma concentration remained essentially unchanged during hypothermia (6.45 ng/ml 5 min into hypothermia and 5.26 ng/ml 100-140 min later; p greater than 0.1). In subsequent experiments, the effect of hypothermia on the pharmacokinetics of fentanyl was studied in 4 piglets serving as their own controls. Both distribution volume (Vz) and total body clearance (CL) were significantly smaller during hypothermia. Our studies indicate that being a drug with a large distribution volume and a high hepatic extraction ratio, both CL and Vz are significantly reduced by hypothermia-induced hypoperfusion. In addition, TBC is influenced by the temperature-dependent hepatic metabolism of fentanyl.

Adolescent↗
PubMed1987

Ventilatory predictors of pulmonary hypoplasia in congenital diaphragmatic hernia, confirmed by morphologic assessment.

We carried out a prospective study in 66 infants with congenital diaphragmatic hernia within the first 6 hours of life to determine whether outcome is related to the degree of underlying pulmonary hypoplasia, as predicted by preoperative PaCO2, when correlated with an index of ventilation (VI = mean airway pressure X respiratory rate) and confirmed by postmortem analysis of the lung. Those infants with PaCO2 greater than 40 mm Hg before surgery had a 77% mortality; when PaCO2 reduction could be achieved only with VI greater than 1000, the mortality was still greater than 50%. After repair, however, the ability to hyperventilate to PaCO2 less than 40 mm Hg proved to be an important determinant of survival; only one of 31 infants in this group died, whereas only two of 27 infants with PaCO2 greater than 40 mm Hg survived. In 16 infants with PaCO2 greater than 40 mm Hg despite hyperventilation, high-frequency oscillatory ventilation was started. This resulted in a rapid fall in PaCO2, but 14 of the 16 infants had only temporary improvement in oxygenation, and died. In five of the infants who died, alveolar number was assessed by postmortem morphometric analysis; there was a severe reduction to less than 10% of published normal neonatal values. Pulmonary vascular changes of increased muscularization were less remarkable than those observed in infants with persistent pulmonary hypertension. Our findings suggest that the degree of pulmonary hypoplasia (which would not be influenced by surgical repair), rather than the pulmonary vascular abnormality, mainly determines survival. Consideration could therefore be given to an initial nonsurgical approach to congenital diaphragmatic hernia, with the expectation that pulmonary function might improve and pulmonary vascular resistance decrease.

Hernia, Diaphragmatic↗
PubMed1987

Changes in pericardial surface pressure during pulmonary hypertensive crises after cardiac surgery.

Reactive pulmonary hypertension in children after surgical repair of large left-to-right shunts is an important cause of postoperative low cardiac output. Low output may be caused by impaired left ventricular filling from right ventricular dilatation. We studied 12 children during the first 72 hr after surgery by measuring right ventricular pericardial surface pressure with a flat balloon and compared the results with acute changes in pulmonary arterial pressure (PAP). All 12 children (ages 4 to 14 months) had preexisting large left-to-right shunts with systemic PAPs. We found a highly significant linear correlation between acute rises in PAP and rises in the pericardial pressure (PP). The regression equation was PAP = 1.48(PP) + 5.7, R2 = .61, p less than .001. There was an average of 15.6 pulmonary hypertensive episodes per patient during the 72 hr study period, but only 9% of these episodes were associated with either no change or a fall in systemic pressure. We conclude that changes in right ventricular pericardial pressure reflect acute changes in PAP.

Heart Defects, Congenital↗
PubMed1986

Clinical experience with systemic vasodilator therapy in the newborn infant.

Newborn infants with impaired myocardial performance may not respond to inotropic drugs and volume loading. Vasodilator therapy was tried in 10 such patients and in most there was improvement in peripheral perfusion, blood pH, arterial oxygenation, blood pressure and urine output. No complications of these drugs were detected. Vasodilator therapy has a role in the management of the acutely sick newborn infant with clinical signs of low cardiac output.

Adult↗
PubMed1986

Partial recovery of neutrophil functions during prolonged hypothermia in pigs.

The changes in circulation and migration of mature and immature neutrophils during 12 h of hypothermia have been studied using an experimental pig model. At 29 degrees C the number of circulating neutrophils fell from 5 +/- 1.1 at 37 degrees C to 3.5 +/- 0.6 X 10(9)/l and then remained unchanged while hypothermia was maintained. The number of circulating immature neutrophils did not fall during hypothermia. During hypothermia, hydrocortisone failed to stimulate the release of mature and immature neutrophils from the bone marrow. In contrast, endotoxin caused a profound neutropenia followed by a gradual increase in the number of circulating mature neutrophils, which by 6 h, was similar to the number circulating before endotoxin administration. At 29 degrees C the number of circulating immature neutrophils also fell following endotoxin but then increased over the number circulating before endotoxin administration by approximately 10-fold. Compared with neutrophil migration at 37 degrees C, very few mature or immature neutrophils migrated to an inflammatory site during the 12 h of hypothermia (29 degrees C). Unlike hypothermia in vitro, where neutrophil function may improve with time in vivo, neutrophil function remains compromised.

Animals↗
PubMed1986

Migration in vitro by blood and exudate neutrophils assessed serially during an inflammatory response.

Migration in vitro by blood and inflammatory neutrophils has been compared serially during an inflammatory response. Using an experimental pig model, neutrophils are isolated from the peripheral blood and from the pleural space at hourly intervals after an intrapleural challenge with zymosan activated pig serum (ZAS). Following acepromazine sedation and halothane anesthesia, blood neutrophil migration was transiently reduced. By 1 hour random and directed migration of blood neutrophils returned to normal. Directed and random migration of exudate neutrophils was markedly decreased to both a stimulus-specific (ZAS) and an unrelated (LTB4) chemoattractant. After 3 hours, migration by exudate neutrophils was similar to migration by blood neutrophils examined in parallel. These findings emphasize the importance of performing serial evaluations of cell function during an inflammatory response.

Animals↗
PubMed1985

Determinants of prognosis in idiopathic dilated cardiomyopathy as determined by programmed electrical stimulation.

The incidence and prognostic significance of electrically induced ventricular arrhythmias were prospectively assessed in 42 patients with idiopathic dilated cardiomyopathy. All patients underwent 24-hour, long-term electrocardiographic (Holter) monitoring and 30 were analyzed by a signal-averaging vectorcardiographic procedure at entry into the study. Their response to programmed electrical stimulation during basic right ventricular pacing was investigated using 1 and 2 ventricular extrastimuli. A monomorphic tachycardia was not induced in any patient. In 36 patients (86%) polymorphic ventricular arrhythmias were initiated. Three or more induced consecutive ventricular premature complexes occurred in 9 patients (21%), nonsustained polymorphic ventricular tachycardia in 2 (4.8%) and ventricular fibrillation in 1 patient (2.4%). There was no association between electrically induced polymorphic ventricular arrhythmias and the degree of impairment of left ventricular function. Furthermore, the incidence of induced ventricular arrhythmias was not related to the Lown grade or to the total number of ventricular premature complexes during Holter monitoring. A late potential was detected by the averaged vectorcardiogram in only 1 of the 30 patients. During follow-up (mean 16 +/- 7 months) 7 patients died, 5 from chronic congestive heart failure and 2 from sudden cardiac death. No patient had an electrically induced arrhythmia of 3 or more ventricular premature complexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Influence of hypothermia on the pharmacokinetics of gentamicin and theophylline in piglets.

The influence of hypothermia on gentamicin and theophylline pharmacokinetics was studied in anesthetized pigs given an iv bolus of gentamicin and theophylline during normothermia (37 degrees C) and again 1 wk later after the induction of controlled hypothermia (29 degrees C). During hypothermia, the elimination half-time for gentamicin was significantly prolonged (135 +/- 19 min at 37 degrees C vs. 187 +/- 7 min at 29 degrees C), and there were significant decreases in the volume of the central compartment (Vc) of gentamicin, the gentamicin volume of distribution (Vd), and the gentamicin total body clearance (TBC). Hypothermia was associated with a small but significant decrease in theophylline Vd and Vc, but no change in TBC. In separate experiments, cardiac output decreased during the induction of hypothermia in a temperature-dependent fashion. The changes in gentamicin Vd and TBC may be explained by the decrease in cardiac output and the associated decrease in glomerular filtration rate. This study suggests that the elimination of theophylline, which has a relatively low hepatic extraction ratio, is not influenced by the hypothermia-induced decrease in liver blood flow.

Animals↗
PubMed1985

An experimental model to study blood and inflammatory neutrophils.

We sought to develop an experimental animal model in order to study the effects of hypothermia on host defences under conditions which were similar to those used for humans. We required a large animal which could tolerate arterial and venous catheters and serial blood sampling without significantly altering its blood volume and blood pressure. The animal should be intubated and ventilated to control blood gases and fluid and electrolyte balance. Finally the model should have anatomic, metabolic and physiologic similarities to humans. We describe an experimental pig model which appears to fulfill these criteria and provide important information relevant to man.

Animals↗
PubMed1984

Intravenous salbutamol in the treatment of status asthmaticus in children.

The management of status asthmaticus using a continuous iv infusion of salbutamol was studied in 14 children with a total of 16 episodes of respiratory failure, unresponsive to conventional bronchodilator therapy. The mean PaCO2 at the start of the infusion was 60 +/- 6 torr. A loading dose of 1 microgram/kg X min body weight was given over 10 min, followed by an infusion of 0.2 microgram/kg X min which was increased in 0.1-microgram/kg steps according to response. The maximum dose was 4 microgram/kg X min. On 11 (69%) occasions a sustained reduction in PaCO2 was achieved within 4 h of starting the infusion. In 5 (11%) instances no reduction in PaCO2 was seen and mechanical ventilation was instituted because of increasing respiratory distress and CO2 retention. Mean heart rate during the infusion increased from 161 to 183 beat/min. Comparison with previous data from 30 pediatric patients (40 infusions) receiving iv isoproterenol showed less effect on heart rate and a more sustained fall in PaCO2 without the recurrence of bronchospasm. We found salbutamol to be a safe and effective bronchodilator capable of reversing severe bronchospasm in most children who would otherwise require mechanical ventilation. Its greater specificity for beta 2-receptors may make it preferable to isoproterenol.

Adolescent↗
PubMed1983

Neutrophil circulation and release from bone marrow during hypothermia.

The effect of hypothermia on neutrophil circulation and release from bone marrow has been studied. Pigs were anesthetized and maintained at 37 degrees C or surface cooled to 29 degrees C over 60 min. As the core temperature was reduced to 29 degrees C, the number of circulating neutrophils (X 10(9) per liter) fell from 6.0 +/- 0.6 to 2.3 +/- 0.3 by 60 min. No significant change in the number of circulating mature or immature neutrophils was observed over the 4 h of observation at 29 degrees C. Neutrophil demargination after administration of intravenous catecholamines was similar at 37 and 29 degrees C. Steroid stimulation of bone marrow to release neutrophils was markedly impaired at 29 degrees C. Circulating mature neutrophils in normothermic pigs increased from 5.6 +/- 1.2 to 10.4 +/- 1.2 by 120 min after administration of intravenous hydrocortisone sodium succinate. Circulating immature neutrophils increased from 1.7 +/- 0.3 to 5.3 +/- 0.4. At 29 degrees C, no significant changes in the number of circulating mature or immature neutrophils occurred. Endotoxin also failed to stimulate neutrophil release from the bone marrow. Furthermore, a marked neutropenia occurred in hypothermic pigs after intravenous endotoxin, which persisted for the 3 h of observation. Neutrophil circulation and release from bone marrow are compromised by hypothermia, which may increase the risk for bacterial infection.

Animals↗