Large-pore hemodialysis in acute endotoxin shock

Objective: This study was undertaken to test the hypothesis that hemodialys is with a large pore membrane would improve heart function during acute end otoxin shock. Setting: Large animal laboratory, Design: Eighteen mongrel dogs were instrumented to measure left ventricular maximum end-systolic elastance (left ventricular maximum elastance at end systole), cardiac output, circumflex artery blood flow, and myocardial mech anical efficiency (CO x MAP/M(V) over dot O-2, where CO is cardiac output,M AP is mean arterial pressure, and M(V) over dot O-2 is myocardial oxygen co nsumption). Plasma catecholamine concentrations were determined by high-per formance liquid chromatography. Endotoxin shack was induced by infusing 5.0 mu g/kg/min of Escherichia coil 0127:B8 endotoxin in the portal vein for 6 0 mins, followed by 2.0 mu g/kg/min of constant infusion, Control dogs (n = 6) received 4.0 mL/kg/min of saline; hemodialysis dogs(n = 6) underwent ve novenous hemodialysis in 50-min intervals using a polysulfone filter (1.2 m (2); mean pore size, 0.50 nm; blood flow rate, 400 mL/min; ultrafiltrate, " zero-balanced"); shams (n = 5) were treated identically to hemodialysis dog s, except that no convective dialysis was performed. A fourth group (n = 6) was treated with dopamine (5.0-7.0 mu g/kg/min, optimal dose for contracti le increase based on dose-response studies). Measurements and Main Results: After 2 hrs of treatment, left ventricular m aximum elastance at end systole increased and was unchanged in controls (30 +/- 5 mm Hg/mm) and shams (24 +/- 6 mm Hg/mm) compared with basal control. Hemodialysis treatment increased contractility (53 +/- 4 mm Hg/mm), as did dopamine treat ment(54 +/- 7 mm : Hg/mm). Endotoxin shock reduced mechanic al efficiency to 45% of basal control; with hemodialysis treatment, left ve ntricular efficiency returned to 64% of basal central measurement, compared with 49% with dopamine treatment. During treatment, myocardial glucose upt ake was increased with hemodialysis compared with other groups. No differen ce was observed among groups for left ventricular end-diastolic pressures o r dimensions, or catecholamine concentrations. Conclusions: Large-pore hemodialysis increased left ventricular contractili ty to a similar degree as dopamine and provided a marginal improvement in m yocardial glucose uptake and mechanical efficiency.