PHYSIOLOGICAL, BIOCHEMICAL, AND HISTOLOGIC CORRELATES ASSOCIATED WITHTIDAL LIQUID VENTILATION

Tidal liquid ventilation (TLV) with perfluorochemical fluid (PFC) has been successfully used experimentally for up to 4 h. However, no studi es of prolonged TLV have been reported. We hypothesized that full-term newborn lambs can safely and effectively be liquid-ventilated for up to 24 h. To lest this hypothesis, 17 lambs were liquid-ventilated; 7 f or 4 h, 5 for 12 h, and 5 for 23 h. Arterial blood samples were obtain ed for PFC uptake, lipid analysis, and blood gas measurements. Tissues were obtained for histologic and biochemical analysis. Arterial blood gas and mean arterial blood pressure were as follows (mean +/- SEM): pH 7.48 +/- 0.04; Paco(2) 30.6 +/- 2.8; Pao(2) 424 +/- 17; mean arteri al pressure 76 +/- 16 mm Hg. PFC blood levels increased rapidly to a m ean of 5.2 +/- 3.9 mu g/mL. PFC tissue levels increased significantly (p < 0.01) from 260 +/- 45 mu g/g at 4 h to 400 +/- 140 mu g/g at 12 h . There was no further increase in PFC tissue levels by 24 h (456 +/- 181 mu g/g). There was a significant difference in PFC concentration a s a function of tissue (p < 0.01). Furthermore, there was a significan t correlation (r = 0.88; p < 0.01) between the amount of PFC and lipid in blood and tissue. Microscopic examination of the lungs demonstrate d no evidence of barotrauma. These data demonstrate that prolonged TLV can be safe and efficacious for up to 24 h in full-term newborn lambs .