Experimental hypocalcemia induced by hemodialysis in goats

Intravital microscopic observation of the microvasculature during hemodialysis in healthy rats

Hemodialysis (HD) provides life-saving treatment for kidney failure. Patient mortality is extremely high, with cardiovascular disease (CVD) being the leading cause of death. This results from both a high underlying burden of cardiovascular disease, as well as additional physiological stress from the HD procedure itself. Clinical observations indicate that HD is associated with microvascular dysfunction (MD), underlining the need for a fundamental pathophysiological assessment of the microcirculatory consequences of HD. We therefore successfully developed an experimental small animal model, that allows for a simultaneous real-time assessment of the microvasculature. Using in-house built ultra-low surface area dialyzers and miniaturized extracorporeal circuit, we successfully dialyzed male Wistar Kyoto rats and combined this with a simultaneous intravital microscopic observation of the EDL microvasculature. Our results show that even in healthy animals, a euvolemic HD procedure can induce a significant systemic hemodynamic disturbance and induce disruption of microvascular perfusion (as evidence by a reduction in the proportion of the observed microcirculation receiving blood flow). This study, using a new small animal hemodialysis model, has allowed direct demonstration that microvascular blood flow in tissue in skeletal muscle is acutely reduced during HD, potentially in concert with other microvascular beds. It shows that preclinical small animal models can be used to further investigate HD-induced ischemic organ injury and allow rapid throughput of putative interventions directed at reducing HD-induced multi-organ ischemic injury.

Treatment of acute kidney injury secondary to oak intoxication with hemodialysis in a miniature zebu

OBJECTIVE

To describe the successful management of acute kidney injury (AKI) secondary to oak intoxication using hemodialysis in a miniature zebu.

CASE SUMMARY

A 1-year-old male intact miniature zebu was presented for evaluation of a 2-day history of lethargy, anorexia, decreased urine production, and dry, firm stool. Initial diagnostics revealed severe azotemia and the bull was presumptively diagnosed with AKI secondary to oak intoxication due to free access to oak trees in the pasture. Despite conventional management with IV fluids and supportive therapy, the degree of azotemia progressively worsened, and the bull became oliguric and fluid overloaded. Two treatments with hemodialysis resulted in reduction of azotemia and ketonemia, and resolution of fluid overload and oliguria. The zebu was discharged from the hospital after 10 days of hospitalization.

NEW OR UNIQUE INFORMATION PROVIDED

To the authors' knowledge, this is the first reported case using hemodialysis for AKI in a bovid. Treatment with hemodialysis was effective in this case resulting in rapid resolution of azotemia, fluid overload, and oliguria. Hemodialysis may hasten the recovery and decrease morbidity and mortality in bovids with AKI.

Influence of altitude on vitamin D and bone metabolism of lactating sheep and goats

This study investigated the influence of alpine grazing on vitamin D (vitD) and bone metabolism in sheep and goats. Two groups of five adult lactating East Friesian milk sheep and Saanen dairy goats were kept on pastures at 2,000 to 2,600 m a.s.l. (SA: sheep alpine; GA: goats alpine) and 400 m a.s.l. (SL: sheep lowland; GL: goats lowland). The animals were milked twice daily and the milk yield was measured. Blood, milk, skin, and forage samples were collected and the left metatarsi were measured with peripheral quantitative computed tomography. The relative humidity and air temperature were recorded and the ultraviolet B (UVB) radiation was measured with a solar meter at both research stations. In addition, animals from the alpine group were equipped with a global positioning system receiver. The UVB radiation was higher at the alpine station (P<0.05) compared to the lowland station. In contrast, both the relative humidity and the air temperature were higher at the lowland station (P<0.04). The group GA produced more milk than GL (P<0.043). No differences in milk production between SA and SL were detected. Only minor differences between the alpine and lowland species groups were found in the total 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D serum concentration and in the 25(OH)D milk concentration. 25-hydroxyvitamin D2 concentration in serum was higher in sheep compared to goats and the 25(OH)D3 concentration in serum increased in all four groups but was higher in the alpine groups during the experiment. In addition, no differences in 7-dehydrocholesterol (7-DHC) concentrations in the skin at high altitude and lowland groups were detectable. However the 7-DHC concentrations in the skin of sheep were less than a tenth of the concentrations in the skin of goats and were nearly not detectable. In both groups SA and SL bone strength index increased during the trial (P=0.043). Bone strength index was lower in GA compared to GL at wk 12 (P=0.047). Mean serum Ca concentrations were higher and P concentrations were lower in the alpine groups than in the lowland groups (P=0.047). In both groups SA and GA the distance travelled increased during the trial. In conclusion, no effect of altitude on vitD status, vitD milk concentration and bone strength could be detected. Both sheep and goats are able to produce vitD in the skin, but sheep depend more on vitD intake with feedstuff, whereas goats rely more on cutaneous vitD production.

Enteral fluid therapy through nasogastric tube in rumen cannulated goats

This paper reports the effects of fluid therapy in goats through nasogastric route with an electrolyte solution composed by concentrations of sodium, potassium and chloride similar to goat plasma (140mmol/L of Na+, 4.5mmol/L of K+, 110mmol/L of Cl-). Four Alpine Chamoisee goats, two of them with evident leakage of the rumen cannulas, were used in a crossover experimental design of two periods and two groups. In one group the two goats were submitted to a treatment protocol to induce dehydration before the fluid therapy, whereas the other group was not. Fluid therapy consisted supplying 10mL/kg/h of the electrolyte solution during 8 hours. No signs of discomfort or stress were observed. The dehydration model employed caused a mild dehydration indicated by decrease in feces humidity, body weight and abdominal circumference, and increase in plasma total solids concentration. During fluid therapy globular volume and plasma total solids decreased, whereas % body weight and abdominal circumference increased. No signs of hyperhydration were observed and serum electrolytes (Na+, Cl-, K+) presented no significant alterations in both groups. Fluid therapy proposed in this study was efficient to treat dehydration, even for rumen cannulated animals with evident leakage, and can be administrated safely with no electrolyte imbalance.

Symptomatic Hypocalcemia Due to the Inadvertent Use of a Calcium-free Hemodialysate

Hemodialysis using a bath with less-than-normal calcium level can cause hypocalcemia. The development of symptomatic hypocalcemia with resultant hypotension after the inadvertent use of a calcium-free dialysate in a maintenance hemodialysis patient is described. It is suggested that the occurrence of similar mishaps in the future can be reduced by close checking of dialysate concentrate labels.