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The authors observed a wide variability in the number of uses per dialyzer in their hemodialysis patients. In 54 patients who reused their dialyzers, heparin dose (U/kg/min) related directly and white blood cell count related inversely to reuseability. Average reuse was 5.1 +/- 2.9 (SD) in diabetics (n = 13) and 7.8 +/- 3.8 (SD) in non-diabetics (n = 41; p = 0.007). Of the diabetics, 77% achieved six or less reuses, and 59% of non-diabetics achieved six or more reuses (chi-square = 4.96; p less than 0.05). In non-diabetics, heparin dose was the most significant determinant of reuse, and in diabetics the major determinant was white blood cell count. Hematocrit levels, platelet count, erythropoietin use, or type of membrane (polysulfone/cellulose acetate) did not correlate with reuseability. It was concluded that reuseability of dialyzers is less in diabetic patients, patients on lower heparin doses (U/kg/min), and patients with higher white blood cell counts. Determinants of dialyzer reuseability warrant further study.

This study presents characteristics of hemorheology for six patients during long-term support (85-144 days) on a Novacor left ventricular assist device (LVAD) as a bridge-to-cardiac transplantation. Results indicate that a certain "baseline" rheology can be identified in patients whose support was uneventful. However, in the patients who had one or more neurologic episodes during support, these events were associated with altered hemorheology, including increases in plasma and relative blood viscosity, and red cell rigidity.

X-ray photoelectron spectroscopy (XPS) was used to determine changes in titanium oxide composition, oxide stoichiometry, and adsorbed surface species as a function of exposure to model physiologic environments. The oxide on titanium became heterogeneous and polarized as a function of exposure. Changes included an increase in surface hydroxyl groups, and adsorption of H2PO4- and HPO4(2-). The heterogeneous nature of the surface led to preferential adsorption of lipoproteins, glycolipids, or both from serum.

Of 11 patients who underwent emergency resuscitation from cardiac arrest using a system of percutaneous cardiopulmonary support (CPS), two (18%) were long-term survivors. Percutaneous cardiopulmonary support was instituted without complication in all patients, with flows ranging from 1.8 to 5.5 L/min; the average duration of support was 304.3 min. All four patients who underwent emergency surgery (two coronary revascularization, one mitral valve revascularization, one mitral valve replacement with coronary revascularization, and one primary left ventricular assist device insertion) died. One patient died while on CPS secondary to irreversible ventricular arrhythmias after a successful percutaneous transluminal coronary angioplasty (PTCA). Six patients were weaned from the support system, three of whom had undergone PTCA while on CPS. The two survivors were the youngest patients (33 and 24 years). One of them had severe hypothyroidism as the cause of cardiac arrest, and the second was a hypothermia patient who was in ventricular fibrillation for 2 hr before establishing CPS. In comparing survivors (two) to nonsurvivors (nine), a significant difference (p = 0.034) in age was found, with survivors being younger. There was also a difference in incidence of atherosclerotic cardiovascular disease (p = 0.018), with survivors having none. There was no difference in the time to CPS (p = 0.905) or time on CPS (p = 0.156). Cardiopulmonary support can be instituted, resulting in excellent stabilization in patients with cardiac arrest. Survivors tended to be young and not have atherosclerotic cardiovascular disease (ASCVD) as their primary diagnosis. Neither length of cardiac arrest before CPS nor time on support correlated with a poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of ventricular assist on acute profound biventricular failure (BVF) was examined in chronic animal experiments using 10 adult goats. Induction of BVF was achieved by normothermic anoxic arrest for 30-60 min during the use of a left ventricular assist system (LVAS, eight goats), or biventricular assist system (BVAS, two goats). The LVAS could maintain near normal circulation with volume loading in six goats, and three of eight goats were weaned from LVAS after 13-18 days. In the early stages, left atrial pressure was significantly higher, and right atrial pressure was significantly lower, compared with measurements in nonweaned goats. During BVAS, circulation was well maintained without volume loading, but neither of the two goats could be weaned from VAS. Myocardial fibrosis in goats without myocardial recovery was significantly more severe. Left ventricular wall thickness was thinner in nonweaned goats and there was a significant inverse correlation between the thickness of the left ventricular free wall and the assist duration in nonweaned goats. Based on these data, it was concluded that myocardial damage was severe in nonweaned cases, and the potential for healing is affected by the severity of myocardial damage before VAS application. Prolonged unloading with VAS of these severely damaged hearts caused loss of left ventricular wall thickness.

The use of recombinant human erythropoietin (r-HuEPO) corrects the anemia of chronic hemodialysis (HD) patients and improves their quality of life. The role of r-HuEPO in the genesis of graft thrombosis is controversial. A retrospective study was conducted of 46 stable chronic HD patients receiving r-HuEPO. It showed an increase in graft thrombosis in those who received the drug.

Four different approaches to calculating the protein catabolic rate (PCR, in g/kg/day) were investigated in 28 stable continuous ambulatory peritoneal dialysis (CAPD) patients and compared to the dietary protein intake (DPI) from a 3 day diet history. The modified Borah technique is based on the hemodialysis correlation, with the addition of measured effluent protein losses. The Randerson technique is a correlation similar to the Borah hemodialysis correlation, but it was established in a CAPD population. The Teehan technique estimates total nitrogen loss by adding the measured urea nitrogen loss to average values from the literature for protein, amino acid, and non-urea nitrogen losses. The Kjeldahl technique measures total nitrogen loss. All four techniques yielded similar PCR values (0.85-0.92 g/kg/day), none of which was significantly different from the DPI (0.89 g/kg/day). Based on the simplicity of the measurements and calculations, the Randerson technique is recommended for routine monitoring of PCR in CAPD patients.

The development of orthotopically positioned cardiac replacement devices requires a knowledge of the space available to guide the design of the blood pumping system. Pericardial dimensions from in vivo and cadaver studies of normal subjects have been reported, but little information is available on in vivo pericardial dimensions in patients with dilated cardiomyopathies. The critical pericardial dimensions were determined in 13 men who were cardiac transplant recipients (age, 42 +/- 13 years; body mass, 72 +/- 11 kg; three with ischemic and 10 with idiopathic cardiomyopathy) by comparison of corresponding pericardial axes on chest radiographs to measurements obtained during orthotopic cardiac transplant in the context of a total artificial heart fit trial. The main pericardial dimensions measured intraoperatively were found to be the T10 midline anteroposterior (AP) axis (12.3 +/- 1.4 cm), the aortic root to diaphragm length (9.7 +/- 1.5 cm), the T10 total cardiac lateral axis (18.1 +/- 2.3 cm), and the tricuspid annulus to left ventricular apex (12.1 +/- 1.7 cm). All patients had cardiomegaly as indicated by a greater than normal cardiothoracic ratio. These data described the limited dimensions of the pericardial space available for orthotopic cardiac replacement devices. Chest film dimensions can be corrected using 0.92 and 0.88 as reduction factors for the (AP) and lateral axis dimensions, respectively. In this patient sample, there was little or no correlation between pericardial dimension and patient body mass or diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanical circulatory support with systems that require transcutaneous cannulas or drive lines are associated with a high incidence of device related infections. The development of infection often is related to the duration of support. Data were reviewed on 10 patients (nine men and one woman) supported with assist devices (Thoratec-five, Nova-cor-three, Sarns-one, Jarvik-one) for longer than 30 days (range, 31-440; mean, 137 days). Seven patients had device related infections. Five also had positive blood cultures with the same organisms responsible for the device related infection. Two had mediastinitis from an ascending infection (one cannula and one drive line). Eight patients were transplanted, with seven survivors. One patient was weaned and survived, and one died during support. These data show that device related infections are common and severe, but they do not preclude successful transplantation, weaning, or survival.

The role of von Willebrand's factor (VWF) was examined in platelet deposition on polyethylene by exposing 3/16 inch diameter discs of polyethylene to 111In labeled platelets re-suspended in citrated blood from normal and severe von Willebrand's disease donors. Discs were oscillated for 30 and 60 min, washed, fixed, counted for 111In, and examined by scanning electron microscopy (SEM). Total platelet deposition in the 0% VWF group was significantly greater than control discs at 30 min (7.0 x 10(6) +/- 0.5 compared with 3.29 x 10(6) +/- 0.6 platelets/cm2). The SEM examination revealed patches of spread platelets, with platelets adhering to platelets in controls. A dense, uniform monolayer of platelets was found on the 0% VWF discs. At 60 min, control discs had significant increases in the platelet deposition with SEM examination revealing uniform coverage of the disc with additional platelets.