We tested the hypothesis that partial liquid ventilation (PLV) with perflubron (LiquiVent®) in spontaneously breathing (SB) animals would increase respiratory rate (RR), minute ventilation (Ve), and work of breathing when compared to animals treated with gas ventilation (GV). We studied 8 newborn piglets after sedation with ketamine, intubation, and placement of catheters and an esophageal balloon. CPAP was initially used, then animals were randomized to sequentially receive different modes of ventilation during GV (Dräger Babylog): IMV-SIMV-AC, or AC-SIMV-IMV. We then instilled perflubron to FRC and repeated the sequence during PLV. Animals returned to CPAP during PLV at the end of the experiment. Each treatment lasted 30 minutes. Ventilator rate during IMV and SIMV, and backup rate during AC, was 10/minute. RR, Ve, and pressure- time product (PTP=ΔPes·Ti, by flow) were measured for all spontaneous and triggered breaths. Standardized PTP•RR is an index of work of breathing. Blood gases were measured and OI calculated every 15 minutes. Reported values are means for the treatment periods. Data analysis used paired t-tests (p<0.05).Table

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PTP•RR index increased during PLV, but only reached statistical significance with AC. Conclusion: SB piglets with normal lungs increase RR and Ve during PLV to maintain normal pH; AC allowed increased Ve without RR change.

LiquiVent(r) supplied by Alliance Pharmaceutical Corp. and Hoechst Marion Roussel.