Objective: To investigate the specific hemodynamic effects of the phosphodiesterase inhibitor milrinone in a rabbit model of septic shock in the absence of any other treatment.
Design: A prospective, controlled, interventional study.
Animal Model: Fourteen sedated New Zealand rabbits.
Setting: Research laboratory of a health sciences university.
Interventions: Rabbits were anesthetized and vascular catheters inserted in femoral artery and jugular vein. After a stabilization period and the recording of baseline measurements (H0), all animals received a 10-mL infusion of Pseudomonas aeruginosa. Two hours later (H2rabbits were randomly assigned to receive 5% dextrose (control group) or milrinone (milrinone group).
Measurements and Main Results: Mean arterial blood pressure (MAP) was monitored continuously, and a cardiac index (CI) was determined every 30 mins by a transpulmonary thermodilution technique using an integrated monitoring device (PICCO). No differences were detected between the two groups after stabilization (H0) or before the treatment (H2) for either CI (mL/min-1/kg-1) or MAP (mm Hg). CI decreased progressively in the control group during the following 4 hrs, but not in the treated group (at H6: 122 ± 4 vs. 207 ± 16 mL/min-1/kg-1; p < .05). No drop of MAP occurred after milrinone infusion. A comparison of the treated and control group reveals that milrinone improved tissue perfusion as evidenced by measurements of central venous saturation (at H4: 0.59 ± 0.05 vs. 0.71 ± 0.03, p = .04), lactacidemia (at H6: 10.3 ± 2.4 vs. 3.9 ± 0.9 mmol/L, p = .03), creatinemia (at H6: 95 ± 11 vs. 60 ± 5 μmol/L, p = .02) and survival (at H6: 5 vs. 7, not significant).
Conclusion: Milrinone improves cardiac output and tissue perfusion in a rabbit model involving severe septic shock.