Journal of critical care
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Journal of critical care · Dec 1993
Comparative StudyThe relationship between the arteriovenous carbon dioxide gradient and cardiac index.
It has been reported that under normal conditions, mixed venous blood gases have approximated arterial samples; however, during cardiac arrest or severe cardiogenic shock, marked differences between arterial and venous blood gases have been noted. To further assess the relationships between arterial and mixed venous blood gases and cardiac index, a study population was chosen consisting of patients with less severe states of cardiac impairment. The differences between arterial and mixed venous PCO2s and pHs were compared with cardiac indexes (CI) of 44 patients in an intensive care unit with arterial lines and Swan-Ganz catheters in place. ⋯ When the CIs of all patients were plotted against the delta PCO2s, there was an inverse linear relationship wherein delta PCO2 increased as CI decreased (r = -.47, P = .0011). There is an inverse relationship between delta PCO2 and CI that has not been previously described. An elevated delta PCO2 may be a marker of a low cardiac index.
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Journal of critical care · Dec 1993
What good are we doing? The role of clinical research in enhancing critical care medicine.
The amount of financial and other resources used by physicians in the treatment of critically ill patients makes it incumbent upon physicians to ensure that sufficient benefit is obtained from these resources and that physicians are in fact doing good for their patients. Knowing that one is in fact doing good requires an understanding of what counts as benefit. Current medical practice suggests that patient benefit is typically understood in terms of physiological changes and responses, highlighting the role of medical subspecialties in patient care. ⋯ This broader understanding calls for an ambitious research agenda so that physicians will be able to learn how they can genuinely help critically ill patients and their families during times of illness. Carrying out such an agenda requires overcoming the ethical challenges of performing research on patients as vulnerable as critically ill patients. It also requires physicians to establish collaborative ties with other professionals so that truly interdisciplinary research can be performed on a routine basis.
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Journal of critical care · Dec 1993
Comparative StudyEffect of pretreatment with anticonvulsants on theophylline-induced seizures in the rat.
Seizures, often with fatal outcome, are a manifestation of pronounced theophylline toxicity. Prodromal symptoms are not always apparent, and the seizures are reported to be, in certain cases, refractory to treatment with anticonvulsant drugs. The purpose of this investigation was to examine, by an established animal model, which of the commonly used anticonvulsants can reduce the central nervous system sensitivity to theophylline neurotoxicity and what should be the preferred treatment in cases in which theophylline toxicity is anticipated. ⋯ Theophylline concentrations in the cerebrospinal fluid, brain, and serum were assayed by a high-performance liquid chromatography method. It was found that pretreatment with either clonazepam, diazepam, phenobarbital, or valproic acid increased the central nervous system thresholds to the theophylline-induced seizures, whereas phenytoin and magnesium sulphate did not attenuate the sensitivity of the brain to the stimulatory action of this widely used bronchodilator. Therefore, whenever theophylline toxicity is suspected, treatment with either diazepam, clonazepam, phenobarbital, or valproic acid can reduce the hazard associated with theophylline-induced seizures.
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Journal of critical care · Sep 1993
Infusion of ultrafiltrate from endotoxemic pigs depresses myocardial performance in normal pigs.
We previously showed a beneficial effect of hemofiltration on hemodynamics of endotoxic shock pigs. To test the hypothesis that this effect of hemofiltration is caused by convective removal of factors that adversely affect hemodynamics during endotoxemia, we infused ultrafiltrate from endotoxic shock pigs into healthy pigs. Their hemodynamics were compared with those of pigs who were infused with ultrafiltrate from healthy pigs. ⋯ The decrease in cardiac output in group 1 was greater than in group 2 (3.3 +/- 0.2 L/min v 0.3 +/- 0.3 L/min, P < .02) and was due to a decrease in stroke volume. The decrease in right ventricular ejection fraction was also greater (0.15 +/- 0.02 v 0.01 +/- 0.00, P < .01). Systemic vascular resistance, right atrial pressure, right ventricular end-diastolic volume, pulmonary wedge pressure and heart rate did not differ between groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Journal of critical care · Sep 1993
Acute renal failure in the critically ill: management by continuous veno-venous hemodiafiltration.
The consequences of newer techniques of continuous renal replacement therapy in critically ill patients are not yet fully known. The clinical and biochemical impact of continuous veno-venous hemodiafiltration (CVVHD) was, therefore, prospectively studied in 60 critically ill patients with acute renal failure. Prospective clinical, biochemical, and hematological data were collected from patients receiving CVVHD. ⋯ Continuous veno-venous hemodiafiltration offers superior azotemia control and a safe approach to renal replacement therapy in critically ill patients. Its use is associated with a comparatively favorable outcome. CVVHD may be regarded as the treatment of choice in such patients.