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Biomedical subjects

R M Perkin

Publications and source records attributed to R M Perkin.

13 recordsLinked to original sources
PubMed1992

Mojave rattlesnake envenomation: prolonged neurotoxicity and rhabdomyolysis.

An 11-year-old girl presented to the emergency department with hypoventilation and shock after being bitten by a Mojave rattlesnake. Intubation was required, and she improved rapidly after fluid resuscitation and antivenom administration. She was extubated four hours after envenomation and did well. The patient subsequently developed increased weakness and cranial nerve paresis and required reintubation for respiratory failure at 30 hours after envenomation despite administration of 30 vials of antivenom. She improved after administration of additional antivenom and was extubated ten hours later. Twenty-four hours after envenomation, signs of rhabdomyolysis were noted with myoglobinuria and a creatine phosphokinase level of 96,400 units/L. Myoglobinuric renal failure was treated with mannitol, hydration, and alkalinization of the urine. The patient's renal and neurological functions improved steadily during the following three to four days. Neurotoxic and myotoxic effects of Mojave venom are known to occur but are not well documented in human beings. Recognition of potential complications from envenomation such as respiratory paralysis and rhabdomyolysis with myoglobinuric renal failure is critical.

Antivenins↗
PubMed1992

Dobutamine pharmacokinetics and pharmacodynamics in pediatric intensive care patients.

OBJECTIVE: To evaluate the pharmacokinetics and pharmacodynamics of dobutamine in critically ill children. DESIGN: A prospective study of pediatric patients receiving continuous infusions of dobutamine in a stepwise format from 2.5 to 10.0 micrograms/kg/min. SETTING: A pediatric critical care unit. PATIENTS: Twelve children ranging in age from 1 month to 17 yrs with primary medical conditions. MEASUREMENTS: Plasma dobutamine concentrations and hemodynamic responses were measured at each infusion rate at steady state. Dose response data were analyzed to determine the threshold or minimum plasma dobutamine concentration necessary for discernible hemodynamic effects. MAIN RESULTS: Dobutamine plasma clearance rates ranged from 40 to 130 mL/kg/min. Each patient presented a linear increase in the plasma dobutamine concentration at each infusion rate (r2 = .97, p less than .001). Plasma clearance rate vs. actual dobutamine concentration did not vary. Cardiac output, BP, and heart rate increased 30%, 17%, and 7%, respectively, at maximal dose. The dobutamine concentration thresholds for changes in cardiac output, BP, and heart rate were 13 +/- 6, 23 +/- 14, and 65 +/- 30 ng/mL, respectively. CONCLUSIONS: There was no effect of plasma dobutamine concentration or infusion rate on plasma clearance rate. For this group of patients, over the range of the intravenous doses studied, dobutamine pharmacokinetics followed a first-order kinetic model. Threshold values for dobutamine usually show increases in cardiac output before changes in heart rate. These data demonstrate that dobutamine is an effective inotropic agent in critically ill pediatric patients and has minimal chronotropic action.

Blood Pressure↗
PubMed1988

Pulmonary hypertension in infants with bronchopulmonary dysplasia.

Seventeen children with oxygen-dependent bronchopulmonary dysplasia, right ventricular hypertrophy, and Doppler echocardiographic evidence of pulmonary hypertension were studied by cardiac catheterization. Fifteen of these patients had pulmonary hypertension when placed in room air; six of these 15 patients were shown to have large systemic-to-pulmonary collateral vessels. The hemodynamic responses to oxygen and hydralazine were evaluated. Five patients developed normal pulmonary artery pressure while receiving supplemental oxygen and were not studied further. Of the remaining ten patients, the six patients with large, hemodynamically significant collateral vessels all had deleterious reactions to hydralazine. Two of the four patients without collateral pulmonary circulation responded to hydralazine with further reductions in mean pulmonary artery pressure. Five of the ten patients who had persistent pulmonary hypertension while receiving oxygen have died. Cardiac catheterization and angiography may provide important diagnostic, therapeutic, and prognostic information in patients with pulmonary hypertension complicating bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1985

Mechanisms and management of anaphylactic shock not responding to traditional therapy.

Anaphylaxis results from the generation and release of a variety of mediators and their effects on various organs. Involvement of the respiratory and cardiovascular systems is of primary importance to the attending physician. Prompt recognition and initial therapy directed to maintenance of an effective airway and circulatory system is critical. Cardiovascular collapse may involve the parallel operation of several mechanisms including hypovolemia, alterations in pulmonary or systemic vascular resistance, depressed myocardial contractility, dysrhythmias, and exogenous drug administration. Although epinephrine is the mainstay of therapy, improvement in cardiovascular status may require aggressive fluid administration, and additional pharmacologic and non-pharmacologic aids.

Anaphylaxis↗
PubMed1979

Low-dose continuous intravenous insulin infusion in childhood diabetic ketoacidosis.

We studied 58 children with diabetic ketoacidosis using a random, prospective protocol, with insulin administered either as a low-dose continuous infusion or as high-dose intermittent subcutaneous injections. There were no statistically significant differences between admission pH and glucose determinations or the time to metabolic correction. The incidence of hypoglycemia and hypokalemia was higher in patients receiving subcutaneous insulin. Insulin levels in the low-dose patients were 85--160 microU/ml. The insulin required to achieve metabolic recovery was 1.6 U/kg in the low-dose group and 4.5 U/kg in the high-dose group (p less than 0.01). Glucose administered at a rate of 3 to 4 g er unit of insulin infused in the low-dose group maintained a serum glucose of 150 to 250 mg/dl. Our studies suggest that low-dose intravenous insulin therapy is safe, as effective as high-dose intermittent subcutaneous injections and avoids the risks of hypoglycemia and hypokalemia. Meticulous attention to individual patient care, however, must remain the most important single variable.

Child↗
PubMedDate not supplied

CBF and CBF/PCO2 reactivity in childhood strangulation.

Four children with self-inflicted strangulation injuries had cerebral blood flow determined by stable xenon computed tomography (XeCTCBF) within 24 hours of admission. All had suffered a severe hypoxic-ischemic cerebral injury; 3 initially had fixed pupils, all were apneic with varying bradyarrhythmias, and the initial mean arterial pH was 7.26 (+/- 0.18). The initial blood glucose values were greater than 300 mg/dl (334 and 351 mg/dl) in the 2 patients who died compared to the 2 who survived (104 and 295 mg/dl). The cardiac index was depressed during the first several days of hospitalization in the 2 patients who died (less than 2.0 L/min/m2) compared to the 2 who survived. Total CBF was normal (63 +/- 8 ml/min/100 gm) and local variations in CBF were present. PCO2 reactivity was determined by hyperventilating the 4 patients for 20 min from an end tidal PCO2 of 39 +/- 3 torr to 29 +/- 1 torr and then repeating the XeCTCBF study. Marked regional variability in the CBF/PCO2 response was observed, ranging from 0.5-5.5 ml/min/100 gm/torr PCO2. In the 2 patients who died, the CBF/PCO2 was decreased (1.2 ml/min/100 gm/torr PCO2) compared to the 2 patients who survived (2.1 ml/min/100 gm/torr PCO2). Although CBF was normal in these 4 children, the hyperventilation response was depressed, variable, and even paradoxical which may be important in the evolution of further brain injury and is a critical factor in deciding whether hyperventilation may be of clinical benefit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗