ABSTRACT
Myocardial performance, measured by systolic time intervals during passive postural stress, was evaluated in patients with end-stage renal disease before and after a single hemodialysis and compared with that of normal volunteers. Predialysis, the patients displayed a sluggish hemodynamic response to sudden postural changes. With tilting to 90 degrees, the patients' heart rate did not increase adequately and left ventricular ejection time (LVET) decreased only slightly in comparison to that of controls. Postdialysis, however, the response to sudden postural change in terms of increases in heart rate, decreases in LVET and decreases in calculated ejection fraction, were indistinguishable from those of control subjects. Since pre-ejection periods were not different from those of controls at any time during the test, we were unable to demonstrate a definite abnormality of myocaridal function before or after dialysis. The marked hemodynamic improvement in response to upright tilting, noted postdialysis, can be best attributed to a dialysis-related reduction in cardiac preload.
Subject(s)
Myocardial Contraction , Physical Exertion , Renal Dialysis , Adult , Aged , Body Weight , Creatinine/blood , Heart Function Tests , Heart Rate , Heart Ventricles/physiopathology , Humans , Kidney Failure, Chronic/physiopathology , Kidney Failure, Chronic/therapy , Male , Middle Aged , Posture , Stroke Volume , Systole , Time FactorsABSTRACT
It has been reported that total hypothermic blood exchange holds promise for the treatment of septic shock in animals. Since this procedure does not carry any mortality in out laboratory, we studied its effect in an acute septic shock model. After the intravenous injection of endotoxin (10 mg/kg) and blood transfusions into 33 dogs, severe haemoconcentration, tachypnoea, tachycardia, low cardiac output, metabolic acidosis and hyperpyrexia led uniformly to death within 5 h. All of these symptoms were prevented in five dogs by total hypothermic blood exchange, instituted 5 min after the endotoxin injection. Nevertheless, all of these treated animals died a delayed death. Since the endotoxin particles are rapidly phagocytosed by the reticulo-endothelial system, even very early total blood exchange cannot dislodge them from their intracellular site.
Subject(s)
Exchange Transfusion, Whole Blood , Shock, Septic/therapy , Animals , Dogs , Female , Hematocrit , Hemodynamics , Hypothermia, Induced , Male , Oxygen/blood , Oxygen Consumption , Phagocytosis , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy , Shock, Septic/chemically induced , Shock, Septic/mortalityABSTRACT
Current systolic time interval techniques have limited clinical applicability since patient co-operation and attention to the carotid pulse and phonocardiogram transducers are required. Therefore only surface electrodes were used to monitor the electrocardiogram and electrical impedance cardiogram first derivative (dZ/dt) in the acquisition of the timing signals. dZ/dt motion artefacts were eliminated by computerised ensemble averaging, thus permitting uninterrupted data acquisition. We studied the continuous response of multistage treadmill exercise on 13 normal volunteers, since maximal distortion of noninvasive measurements occurs in dynamic exercise. The individual response trends were combined for 6 symbolic indices and each mean index had a high statistical significance (P less than 0.001). This new method surveys continuously ventricular performance with surface electrodes and therefore has the potential of monitoring the ventricular performance of critically ill patients.
Subject(s)
Myocardial Contraction , Physical Exertion , Systole , Adolescent , Adult , Cardiography, Impedance , Electrocardiography , Exercise Test/methods , Humans , Male , Monitoring, Physiologic/methodsABSTRACT
In anesthetized, oxygen-breathing rabbits, the entire blood volume was exchanged with a 20% colloidal fluorocarbon fluid suspension of high gas solubility. In contrast to the control animals with acute isovolemic and hypervolemic hemodilution, the fluorocarbon suspension prevented the decrease in arterial oxygen content below a hematocrit of 13%. However, the more pronounced effect of the fluorocarbon suspension on oxygen delivery occurred at higher hematocrits and was due to its efficiency as a plasma expander, since it increased the cardiac output even above the level of the hypervolemic hemodilution group. The fluorocarbon suspension also raised arterial blood pressure and total peripheral resistance due to its increased viscosity. Thus, in mild hemodilution, the fluorocarbon suspension kept oxygen utilization in the normal range by increasing cardiac output, and in extreme hemodilution it improved oxygen utilization by also raising the arterial oxygen content and arterial blood pressure. The survival time of the isovolemic control animals was 31.6 min, it was extended to 57.8 min in the hypervolemic control animals, and the rabbits with the fluorocarbon suspension lived for 124.8 min.
