ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Multicenter Study
Percutaneously inserted silastic jugular hemodialysis catheters seldom cause jugular vein thrombosis.
To find out whether internal jugular vein cannulation with a soft silastic hemodialysis access catheter causes jugular vein thrombosis, the authors carried out Doppler ultrasound examinations on 96 patients receiving hemodialysis who had undergone 144 separate catheter insertion episodes in 116 veins. Two internal jugular vein thromboses were found in 101 veins that had been the site of percutaneous insertions only. ⋯ The authors conclude that percutaneous internal jugular vein cannulation for hemodialysis access causes an acceptably low incidence of jugular vein damage. This strengthens the case for preferential use of the internal jugular vein for vascular access in patients with end-stage renal failure, and suggests that percutaneous cannulation is less damaging than surgical insertion.
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To analyze the hemodynamic parameters during prosthetic circulation as an entity, non linear mathematical techniques were used. To compare natural and prosthetic circulation, two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses in chronic animal experiments using adult goats to consitute the biventricular bypass complete prosthetic circulation model with ventricular fibrillation. After implantation, these goats were placed in a cage and extubated after waking. ⋯ However, a simple attractor, such as a limit cycle attractor, was observed during artificial circulation. Positive Lyapunov exponents during artificial circulation suggest the lower dimensional chaotic system. Thus, hemodynamic parameters during prosthetic circulation must be carefully controlled when unexpected stimuli are fed from outside.
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The anaerobic threshold represents an objective measure of functional capacity and is useful in assessment of pulmonary and cardiovascular dysfunction. This study determined the anaerobic threshold in total artificial heart animals and evaluated the performance of the total artificial heart system. Five animals with total artificial hearts were put under incremental exercise testing after exercise training. ⋯ The value of the anaerobic threshold in total artificial heart animals implies that the performance capacity of a total artificial heart is not sufficient to meet the oxygen requirements of vigorously exercising skeletal muscle. The protocol does not allow for driving parameter changes during exercise, and this situation, combined with the manual mode of the control system used, was inadequate to allow the total artificial heart animals to exercise more vigorously. Using an automatic control mode might be helpful, as well as considering the relationship between indices of oxygen metabolism, such as oxygen delivery, oxygen consumption, and oxygen extraction rate, in the control algorithms in total artificial heart control systems.
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Clinical Trial
Efficacy of extracorporeal life support in the setting of adult cardiorespiratory failure.
The efficacy of extracorporeal life support (ECLS, ECMO) in the management of severe adult cardiorespiratory failure remains controversial. The purpose of this review is to evaluate the authors' institutional experience with ECLS in adult patients. Between 1988 and 1993, 65 moribund patients with respiratory (n = 51) and cardiac (n = 14) failure were supported with ECLS. ⋯ The only prognostic indicator of survival that could be identified was the period of time on the ventilator before the initiation of ECLS (survivors = 3.0 +/- 2.4 days, nonsurvivors = 6.1 +/9- 4.0 days, P < 0.005). It is concluded that ECLS can be a life saving modality for the management of severe adult cardiorespiratory failure. Earlier institution of ECLS in the course of cardiopulmonary failure may improve outcome.