Artificial organs
-
Clinical Trial
Effects of mild hypothermic cardiopulmonary bypass on blood viscoelasticity in coronary artery bypass grafting patients.
The purpose of this study was to determine the changes in blood viscoelasticity during and after coronary artery bypass grafting (CABG) and to identify correlations between blood viscoelasticity and patients' age, duration of cardiopulmonary bypass (CPB), and cross-clamp time. After Institutional Review Board approvals, patients (n = 10) who were subjected to mild hypothermic CPB were included in this study. Viscosity and elasticity were measured at strains of 0.2, 1, and 5 using a Vilastic-3 Viscoelasticity Analyzer. ⋯ In particular, elasticity of blood was diminished during normothermic bypass and could not be recovered after CPB (p < 0.01). Although there were strong correlations between blood viscoelasticity, duration of CPB, and cross-clamp time on normothermic CPB, only the patients' age showed a positive correlation between viscosity (r = 0.61, p = 0.05), and elasticity (r = 0.89, p < 0.001) after CPB. These results suggest that mild hypothermic CPB alters the blood viscoelasticity during and after CABG.
-
Controversy over benefits of pulsatile flow after pediatric cardiopulmonary bypass (CPB) continues. Our study objectives were to first, quantify pressure and flow waveforms in terms of hemodynamic energy, using the energy equivalent (EEP) formula, for direct comparisons, and second, investigate effects of pulsatile versus nonpulsatile flow on cerebral and renal blood flow, and cerebral vascular resistance during and after CPB with deep hypothermic circulatory arrest (DHCA) in a neonatal piglet model. Fourteen piglets underwent perfusion with either an hydraulically driven dual-chamber physiologic pulsatile pump (P, n = 7) or a conventional nonpulsatile roller pump (NP, n = 7). ⋯ In the right and left hemispheres, cerebellum, basal ganglia, and brainstem, blood flow resembled the global cerebral blood flow. Cerebral vascular resistance was lower (p < 0.007) and renal blood flow was improved fourfold (p < 0.05) for P versus NP, after CPB. Pulsatile flow generates higher hemodynamic energy, enhancing cerebral and renal blood flow during and after CPB with DHCA in this model.
-
There is not yet agreement about the optimal size of the prostheses in aortic and mitral valve replacement with Manouguian's technique. In this technique, the aortic prosthetic valve can be pushed upon the mitral prosthesis which may cause dysfunction of the aortic prosthetic valve. The aim of this study was to clarify the size of the prostheses needed to avoid dysfunction of the aortic prosthetic valve. ⋯ Aortomitral continuity involved with abscesses could be approached and completely excised using this technique. All patients survived the operation, but 1 of them suffered aortic mechanical valve dysfunction for the reason stated. Anatomical analysis of the geometrical relation of the 2 prosthetic valves suggests that the mitral annulus should be enlarged less than 25 mm to avoid dysfunction of the aortic prosthetic valve.
-
Randomized Controlled Trial Clinical Trial
Restitution of reaching and grasping promoted by functional electrical therapy.
Functional electrical therapy (FET) is a new term describing a combination of functional electrical stimulation that generates life-like movement and intensive exercise in humans with central nervous system lesions. We hypothesized that FET can promote a significant recovery of functioning if applied in subacute stroke subjects. The study included 16 stroke subjects divided into a low functioning group (LFG) and a high functioning group (HFG) based on their ability to control wrist and fingers and randomly associated into FET and controls. ⋯ The functional improvement in the FET LFG is probably not sufficient to make the more affected arm/hand effective for daily necessities; thus, the FET effects could deteriorate over a longer time. The subjects from the control LFG made only a marginal improvement. The follow-up for each subject will continue for 12 months after the beginning of the treatment.
-
This article reports preliminary results of pilot studies of a new implantable two channel drop foot stimulator. The stimulator consists of an externally worn transmitter inductively coupled to an implanted receiver unit located in the lower leg, lateral and distal to the knee. The receiver is connected to electrodes located under the epineurium of the deep and the superficial peroneal nerves. ⋯ The location of the electrodes allows for a degree of selectivity over the resultant moment about the ankle joint that is not possible with surface stimulation of the common peroneal nerve. The two subjects used the stimulator on a regular basis and showed increases in walking speed of between 10% and 44% when compared to their baseline measurements. Isometric tests have demonstrated that the stimulator allows selective and repeatable stimulation of ankle joint muscles.