Thrombolytic therapy after cardiac arrest and its effect on neurological outcome.

OBJECTIVE: the aim of the study is to investigate the effect of thrombolytic therapy on neurological outcome in patients after cardiac arrest due to acute myocardial infarction. Laboratory investigations have demonstrated that thrombolytic therapy after cardiopulmonary resuscitation improves neurological function. METHODS: from July 1991 to June 1996, patients with witnessed ventricular fibrillation cardiac arrest due to acute MI and successful restoration of spontaneous circulation admitted to the emergency department were analyzed retrospectively. A logistic regression model was used to assess the association between thrombolytic therapy and neurological outcome [best cerebral performance category (CPC) within 6 months after cardiac arrest]. RESULTS: all 157 patients [median age 57 years (IQR 50-69)] were analyzed. Thrombolytic therapy was applied in 42 patients (27%). With thrombolytic therapy good functional neurological recovery (CPC 1 or 2) was achieved more frequently (69 vs. 50%, P=0.03). After controlling for age, prehospital dosage of epinephrine, and the duration of cardiac arrest we found a non significant trend towards good neurological recovery when thrombolytic therapy was given (OR 1.9, 95% CI 0.8-4.6). CONCLUSION: thrombolytic therapy after cardiac arrest due to acute myocardial infarction is associated with improved neurological outcome.

Negative chronotropic effects of fentanyl attenuate beneficial effects of dobutamine on oxygen metabolism: hemodynamic and pharmacokinetic interactions.

Opioids are well known to cause cardiovascular depression. The aim of the present investigation was to determine whether an interaction of opioid derivatives with catecholamines might be involved in these hemodynamic alterations. Six comatose patients were enrolled into a prospective, nonrandomized pilot trial. All patients first received a continuous i.v. infusion of dobutamine (10 microgram. kg-1. min-1) paralleled by continuous administration of midazolam (0.4 mg. kg-1. h-1); thereafter, fentanyl was added i.v. (4 microgram. kg-1. h-1). Hemodynamic parameters as well as dobutamine and endogenous catecholamines plasma levels were determined. The mean arterial blood pressure did not change significantly during the whole study period. The continuous administration of dobutamine (steady-state plasma concentrations: 217 +/- 118 ng. ml-1) increased the beta1-adrenergic receptor-mediated hemodynamic parameters such as heart rate, stroke volume index, cardiac index, and oxygen delivery index (p <.05). The concomitant administration of fentanyl decreased the heart rate-dependent hemodynamic parameters (p <.05), suggesting that fentanyl antagonizes the chronotropic effects of dobutamine. In parallel, dobutamine plasma levels increased significantly (275 +/- 165 ng. ml-1; p <.05). Noteworthy, after administration of fentanyl, oxygen delivery and consumption index returned to baseline values. Radioligand binding experiments on rat cardiac ventricular microsomes ruled out a direct interaction of fentanyl with beta-adrenergic receptors and, more importantly, a fentanyl-induced inhibition of beta-adrenergic receptor G protein coupling. Our observations suggest that fentanyl inhibits the frequency-related hemodynamic changes induced by dobutamine. The underlying mechanism is independent of beta-adrenergic receptors, but is powerful enough to abolish the salutary effect of dobutamine on oxygen delivery and consumption.

Cardiorespiratory consequences to hobble restraint.

UNLABELLED: Mechanical restraints in agitated, violent psychiatric patients are still sometimes in use in the initial phase of emergency treatment, especially when patients are taken to hospital by law enforcement. Sudden death has occurred in persons in hobble restraint. Cardiopulmonary response to prone or upright hobble restraint for three minutes was investigated in six male volunteers in randomised crossover trial. RESULTS: No change was observed in the investigated cardiopulmonary parameters after hobble restraint in the upright position. After hobble restraint in the prone position, mean forced vital capacity decreased by 39.6%, mean forced exspiratory volume by 41%, mean end-tidal carbon dioxide increased by 14.7%, mean heart rate decreased by 21.3%, mean systolic blood pressure decreased by 32.3%, mean diastolic blood pressure decreased by 26.1% and mean cardiac output decreased by 37.4% (P for all reported changes < 0.01). CONCLUSION: Hobble restraint in the prone position leads to a dramatic impairment of hemodynamics and respiration. Upright position and frequent control of vital parameters are necessary to prevent a possibly fatal outcome in persons in hobble restraint.

Epiluminescence microscopy of small pigmented skin lesions: short-term formal training improves the diagnostic performance of dermatologists.

BACKGROUND: Epiluminescence microscopy (ELM) makes subsurface structures of the skin accessible for in vivo examination and provides additional criteria for the clinical diagnosis of pigmented skin lesions (PSLs). We demonstrated that ELM increases diagnostic sensitivity in dermatologists formally trained in the use of this technique but decreases diagnostic ability in dermatologists not formally trained in its application. OBJECTIVE: Our purpose was to determine the effects of short formal ELM training on the diagnostic performance of 11 previously untrained dermatologists. METHODS: One hundred image-pairs of randomly selected histologically proven PSLs, photographed with (ELM) and without oil immersion (surface microscopy), were presented by slide projection to the testees. To evaluate the effects on diagnostic performance before and after short-term training, we used the receiver-operator characteristics technique. RESULTS: Without training the use of ELM did not enhance diagnostic accuracy, but rather decreased it in 8 of 11 testees. In contrast, after 9 hours of formal training in ELM the diagnostic performance of the testees was significantly enhanced with an average gain of 8.4%. CONCLUSION: Our data confirm that formal training is required for the useful application of the ELM technique.

Effect of alcohol on body core temperature during cold-water immersion.

This study investigates the influence of alcohol on body core temperature during cold-water immersion in human volunteers. In this randomised, double-blind, placebo-controlled crossover trial, 8 healthy male volunteers were randomised to drink 1 litre of beverage containing 50 g alcohol or placebo before 20 degrees C cold-water immersion for 1 hour. Body core temperature was measured before cooling and after 1 hour of immersion with an infrared ear thermometer. After a 1-week interval subjects crossed to the other study branch. In the placebo test, mean temperature decreased after immersion by 0.66 degrees C; after the alcohol mean temperature decreased by 1.0 degrees C (mean difference 0.34, 95% CI 0.14-0.53, P = 0.002).