Long-Term Tidal Liquid Ventilation in Premature Lambs: Physiologic, Biochemical and Histological Correlates

Abstract

Chronic lung disease in infants continues to be problematic. Tidal liquid ventilation (TLV) improves lung mechanics and provides effective gas exchange. We hypothesized that premature lambs could be supported safely with TLV and evaluated 9 preterm lambs (132 days gestation) on TLV up to 72 h. Results (mean ± SEM): pH 7.36 ± 0.003, Pa_CO2 44 ± 0.34 mm Hg, Pa_O2 170 ± 4.8 mm Hg, compliance = 1.65 ± 0.24 ml/cm H₂O/kg, mean arterial blood pressure = 53 ± 0.08 mm Hg, heart rate = 189 ± 1.5 bpm. Blood perflubron levels were 6.0 ± 0.24 µg/ml over 24 h. Tissue perflubron levels increased from 81 ± 7.0 µg/g at 24 h to 108 ± 15 µg/g at 72 h (p < 0.05). There was a difference in perflubron concentrations as a function of tissue (p < 0.001) that correlated to lipid levels (r² = 0.93, p < 0.01). These data demonstrate that TLV is both safe and effective up to 72 h in premature lambs.

A Liquid Ventilator Prototype for Total Liquid Ventilation Preclinical Studies

“…Results in the present and previous (Avoine et al, 2011;Beaudry 2009;Robert et al 2010) studies show that our custom-designed bubble oxygenator can oxygenate PFC at a level up to Fi PFC O 2 =96%, which is similar to previously published data obtained with a silicone hollow fiber membrane oxygenator in rabbits (93%, when considering a standard atmospheric pressure of 760 mmHg) (Tredici et al, 2004) or commercial membrane oxygenator (84%) (Cox et al, 2003;Stavis et al, 1998). In addition, the maximal PaO 2 of 234 mmHg obtained herein is similar to the PaO 2 value of 201 mmHg previously reported in healthy newborn lambs by others (Hirschl et al, 1995;Larrabe et al, 2001;Stavis et al, 1998, www.intechopen.com Progress in Molecular and Environmental Bioengineering -From Analysis and Modeling to Technology Applications 336 Cox et al 2003).…”

“…In addition, the maximal PaO 2 of 234 mmHg obtained herein is similar to the PaO 2 value of 201 mmHg previously reported in healthy newborn lambs by others (Hirschl et al, 1995;Larrabe et al, 2001;Stavis et al, 1998, www.intechopen.com Progress in Molecular and Environmental Bioengineering -From Analysis and Modeling to Technology Applications 336 Cox et al 2003). Beyond their low cost and simplicity of use, the present study clearly shows that bubble oxygenators can be highly efficient during TLV.…”

“…A decrease in the oxygen flow rate through the oxygenator is not a suitable solution, since they it compromises the PaCO 2 , before any effect on PaO 2 reduction. The choice of a bubble oxygenator could be seen as a limitation, since most research groups use membrane oxygenators with TLV (Corno et al 2003;Cox et al 2003;Hirschl et al, 1995;Larrabe et al, 2001;Parker et al, 2009;Pohlmann et al, 2011;Tredici et al, 2004). On the contrary, we strongly believe that bubble oxygenators are quite suitable for TLV.…”

“…However, the insertion of a pressure sensor in the mouth can be problematic in a clinical context, thus the main issue is to adapt this pressure controlled mode without a pressure sensor in the trachea. Many efficient demonstrations of TLV have been performed with different prototypes (Corno et al 2003;Cox et al 2003;Degraeuwe et al, 2000a;Hirschl et al, 1995;Larrabe et al, 2001;Meinhardt et al, 2000;Parker et al, 2009;Pohlmann et al, 2011;Sekins et al, 1999;Tredici et al, 2004). With O 2 saturated PFC and limited to low minute ventilations (comparatively to CMV), they obtained acceptable ventilation.…”

Intranasal Perfluorochemical Spray for Preferential Brain Cooling in Sheep

“…Numerous safety studies have been performed regarding uptake, elimination and biodistribution following PFC exposure [60][61][62][63][64][65][66]. Results demonstrate that only small quantities of PFC diffuse across the tissue membranes and dissolve into blood (0.25-10 lg PFC/ml blood) [67,68].…”