Parallel dialysis normalizes serum chemistries during venovenous perfusion induced hyperthermia

Whole-body hyperthermia is currently under investigation as a method to treat systemic malignancies; however, available techniques induce a derangement in serum and urine chemistries. This study was done to determine whether veno-venous perfusion induced hyperthermia (vv-PISH) that incorporated a parallel dialysis system to control blood chemistries would eliminate these heat induced derangements. Adult female Yorkshire swine were divided into perfusion only (group P, n = 6, 62.8 ± 2.5 kg), and perfusion with dialysis (group PD, n = 6, 63.8 ± 4.3 kg). In both groups, hyperthermia was induced with a computer assisted jugular-to-femoral veno-venous heat exchange/perfusion system primed with a balanced electrolyte solution, operating at 30 ml/min^-1/kg^-1, which used a thermal gradient induced by blood heated to a maximum of 48°C and a perfusate-to-blood temperature gradient <10°C during heating. The target core temperature was 43°C for 120 min as measured by the average of the rectal, bladder, esophageal, bilateral tympanic, and pulmonary artery temperatures. Including ramp-up and cool down, the total perfusion interval was 263 ± 29 min in group P and 240 ± 18 min in group PD (ns). Serum and urine chemistry values expressed as the mean value ± SEM were compared before and after hyperthermia treatment. Variables include blood urea nitrogen, creatinine, sodium, potassium, chloride, calcium, magnesium, phosphorus, glucose, total protein, albumin, alkaline phosphatase (ALKP), creatinine kinase, aspartate aminotransferase, alanine aminotransferase (ALT), lactate dehydrogenase (LDH), plasma free hemoglobin, urine specific gravity, pH and urine creatinine. All variables remained within normal ranges for the PD group. In the P group, the following final values were outside the normal range: (normal range) creatinine 2.1 ± 1 (0.4-1.4) mg/dl Ca²⁺ 5.1 ± 1 (6-13) mg/dl, Mg²⁺ .8 ± 0.1 (1.2-10) mg/dl, ALKP 134 ± 6 (34-122) U/L, ALT 69 ± 3 (9-51) U/L, and LDH 1291 ± 237 (300-600) U/L. We conclude that the significant changes in serum and urine chemistries associated with vv-PISH are normalized with the use of a parallel dialysis system and may decrease the incidence of electrolyte associated complications.