Clearance of serum solutes by hemofiltration in dogs with severe heat stroke

BACKGROUND: We have previously reported that hemofiltration (HF) may be an effective additional means of treating heat stroke when rapid cooling is not effective. METHODS: Dogs were assigned to a heat stroke (control) or heat stroke + hemofiltration (HF) group (n = 8 each group). After heat stroke induction, dogs in the HF group received HF for 3 h. Serum concentrations of interleukin (IL)-10, tumor necrosis factor (TNF)-α, IL-6, blood urea nitrogen (BUN) and creatinine were measured at baseline and 1, 2, and 3 h after heat stroke. Clearance rates of solutes were determined 1, 2, and 3 h after the start of HF. RESULTS: Serum concentrations of all solutes tended to increase with time after heat stroke in the control group, but decreased (BUN, creatinine) or remained relatively unchanged (TNF-α, IL-6, IL-10) with time in the HF group. Concentrations of all solutes were significantly lower in the HF group compared with the control group at 2 and 3 h (P < 0.05). Clearance rates for small molecular weight solutes were high, while those for larger molecular weight solutes were low. CONCLUSION: HF prevents heat stroke-induced increases in serum cytokine concentrations and is effective for clearing small molecular weight solutes from serum, but less effective for clearing larger molecular weight solutes, including TNF-α, IL-6, and IL-10.