The International Journal of Artificial Organs

We studied hand function by clinical examination (sensory, motor, coordination, activities of daily living), hand roentgenograms, and nerve conduction studies in 26 patients, aged 62 ± 11 (SD) years and dialyzed by hemodialysis for 7 ± 6 years. Multiple sensory deficits were found in 98% of the hands. Motor function and coordination were abnormal in two-thirds of the hands. Roentgenograms were abnormal in 88% of the hands. Metabolic bone disease, joint disease and extraosseous calcifications were detected often. Nerve conduction studies disclosed polyneuropathy and carpal tunnel syndrome, alone or combined, in 90% of the hands. Clinical examination was sensitive, but not specific in detecting neuropathy, and could not distinguish accurately between polyneuropathy and carpal tunnel syndrome. Organic causes of progressive severe hand dysfunction included carpal tunnel syndrome and, in diabetics only, hand gangrene. Disuse led also to hand dysfunction, even in the absence of anatomic hand disease.

Biochemical changes that had appeared after subtotal parathyroidectomy (PTx) in 26 patients with end-stage renal failure were observed. The volume of excised parathyroid glands was also measured. Serum calcium and inorganic phosphorus levels fell after PTx; only to rise in due course. Serum alkaline phosphatase levels rose after PTx, reaching a peak by the 14th postoperative day. These elevated levels returned to normal range at about three months after PTx. Strong correlation was noted among the degree of postoperative hypocalcemia, and increase in serum alkaline phosphatase, but not between absolute pre or postoperative alkaline phosphatase levels and changes in serum calcium or phosphorus concentrations. Nevertheless, significant correlation was seen between pre-PTx levels of alkaline phosphatase and its short-lived postoperative rise, indicating hastened osteoblastic activity.

Fifteen patients on regular dialytic treatment for more than 15 years were given X-rays of the skull, spine, shoulders, wrists, pelvis and knees with the purpose of studying the principal skeletal and articular alterations due or not due to the uraemic status. Serum calcium, phosphorus, parathyroid hormone, alkaline phosphatase and basal aluminium were recorded. Osteopenia was evident in all the patients. Ten of whom (67%) showed alterations due to hyperparathyroidism. Nine patients presented the marks of dialysis spondyloarthropathy; in 14/15 cases geodes were present in the wrists, humeral heads or hip-joints; in ten patients there were multiple amyloid lesions. Two patients with serum basal aluminum above 100 μg/L showed the typical radiographic marks of osteomalacia. The majority of the long-term survivors showed multifactorial osteo-articular alterations resulting mainly from the combination of hyperparathyroidism and dialysis-related amyloidosis. The less frequent joint alterations were represented by arthrosis, enthesopathy and Chondrocalcinosis. Disability and decreased articular mobility resulted in being mainly due to amyloid osteo-arthropathy.

The response of the parathyroid glands to dialysis-induced changes in calcium has been studied in 83 normocalcemic patients receiving maintenance hemodialysis. Predialysis concentrations of intact parathyroid hormone (iPTH) were normal in 13 patients; 70 patients had increased iPTH levels of different degrees. All patients had analytically significant changes in total serum calcium (2.3 ± 0.2 vs 2.8 ± 0.2 mmol/l) without additional parenteral calcium loading during a standard dialysis session with a dialysis solution of 1.75 mmol calcium chloride. During hemodialysis the concentration of iPTH fell in 77 patients and was normalized in 48 of these patients. The remaining 6 patients showed no or an inadequate response (less than 30% suppression of predialysis iPTH) to the increase in Ca. Parathyroidectomy was performed in patients with refractory iPTH secretion. Histological evidence of marked parathyroid hyperplasia was obtained in all these patients. All patients with normal or partial responsiveness of the parathyroids tolerated at least small doses of 1.25 (OH)₂-vitamin D₃. Quantification of predialysis and postdialysis iPTH concentrations is a useful and simple method for identifying those uremic patients with true autonomy of the parathyroid glands at an early stage.

Normally the differences in arterial-venous pH (A-VpH) and veno-arterial pCO₂ (V-ApCO₂) are small and constant. This study deals with A-VpH and V-ApCO₂ and their effect on arterial-venous saturation hemoglobin percentage (A-VSHb%) in uremic patients under hemodialysis (HD). In 17 uremic patients under HD with acetate, blood samples were collected anaerobically in heparinized syringes from artery (fistula) and vein (forearm without fistula) pre- and post-HD. In these samples pH, pCO₂ and SHb% were determined and A-VpH, V-ApCO₂ and A-VSHb% were estimated. Comparison between the values pre- and post-HD of A-VpH, V-ApCO₂ and A-VSHb% shows that these three values were decreased significantly post-HD (p<0.001). The correlation of all values (pre- and post-HD) of A-VpH and V-ApCO₂ with that of A-VSHb% was significant and positive (r=0.514 p<0.01, r=0.505 p<0.01, respectively).

Persistence of gross hematuria for more than three days following renal biopsy merits renal angiography and embolization of the involved branch of renal artery. We report a patient who developed a fatal intracerebral hemorrhage resulting from severe hypertension following embolization of a branch of the left renal artery.

Numerous devices and mock circulations have been described for the measurement of pressure loss, closure time, closing and leakage volumes and energy loss in artificial heart valves. However, all the devices have been troubled with difficulties in generating and assessing the precise flow through the valve, and problems in defining the arterial load, i.e. the artificial aorta. The new test device follows a radically different approach: a computer controlled piston forces the fluid through the test valve only — with no afterload. During systole, outflow follows a physiological curve which is identical for all types of heart valves of a given size. During diastole a mathematically defined physiological pressure difference curve is followed. Consequently, the measurements are independent of the individual machine, the lab where testing takes place, the scientist who executes the test, the time when measurements are taken and all other external influences.

Long-term extracorporeal liver perfusion of up to 24 hours was achieved with an improved model of pig liver perfusion. Functional and structural integrity of the extracorporeal liver was maintained during the entire duration of extracorporeal perfusion. After 24 hours SGOT was 33.5 (± 6.5) U/L, bile production was 11.5 ml/h. Survival of hepatectomized pigs could be extended to 18.9 (± 3.8) hours with extracorporeal liver perfusion (p < 0.01). The improvement of liver perfusion in our particular model is primarily based on optimised perfusion of the low pressure system of the portal and hepatic vein by the application of sinusoidal pressure profiles. These pressure profiles imitate intra-abdominal conditions and achieve homogeneous perfusion of the low pressure system of the portal vein and complete drainage of hepatic venous blood.

We investigated the influence of pre-harvesting general hypothermia on liver metabolic activity by means of Aminopyrine Breath Test (ABT). This study was conducted in pigs which were anesthetized, curarised and cooled on an ice bed. Each animal received labelled aminopyrine and ¹⁴CO₂ in expired air was measured between 37.5 and 25.5° C. The liver metabolic activity at 31.5° C represents 53.3% of the normothermic value. At 25.5° C, this activity is reduced by 75.1%. The mean decreasing rate is 6.2%/° C for a fall in temperature of 12° C. A change of slope occurred at 31.5° C. The first decreasing rate is 7.47 ± 1.62%/° C and the second one is 4.48 ± 2.27%/° C. Thus, use of general hypothermia during liver harvesting should improve the quality of organ preservation: the important reduction of metabolism should decrease the oxygen debt resulting from anaerobic cold perfusion.