Oxygenation index, an indicator of optimal distending pressure during high-frequency oscillatory ventilation?

• Published in: Intensive care medicine Vol. 28; no. 8; pp. 1151 - 1156
• Main Authors: van Genderingen, Huibert R., van Vught, Johannus A., Jansen, Jos R., Duval, Elisabeth L., Markhorst, Dick G., Versprille, Adrian
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.08.2002; Berlin Springer Nature B.V
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; Distension; Emergency and intensive respiratory care; High-Frequency Ventilation; Intensive care medicine; Lungs; Medical sciences; Oxygen - supply & distribution; Oxygenation; Physiology; Prospective Studies; Respiratory Distress Syndrome, Adult; Swine; Ventilation; Performance evaluation; Animal model; Intensive care; Respiratory intensive care; Artificial ventilation; Index (documentation); Indicator; Pig; Vertebrata; Mammalia; Newborn animal; Artiodactyla; Oxygenation; High frequency ventilation; Mechanical ventilation; Ungulata
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-002-1368-5

To test the hypothesis that, during high-frequency oscillatory ventilation (HFOV) of pigs with acute lung injury, the oxygenation index (OI = Paw*FIO(2)*100/PaO(2)) is minimal at the lowest continuous distending pressure (Paw), where the physiological shunt fraction is below 0.1 (Paw(optimal)). Prospective, observational study in a university research laboratory. Eight Yorkshire pigs weighing 12.0+/-0.5 kg, with lung injury induced by lung lavage. After initiation of HFOV, the pigs were subjected to a stepwise increase of Paw to obtain under-inflation, optimal inflation and over-distension of the lungs (inflation) in series, followed by a similar decrease of Paw (deflation). At each Paw level, the OI and physiological shunt fraction were determined. The OI reached a minimum of 6.2+/-1.4 at Paw 30+/-4 cmH(2)O during inflation and a minimum of 2.4+/-0.3 at Paw 13+/-2 cmH(2)O during deflation. Paw(optimal) was 32+/-6 cmH(2)O on the inflation limb and 14+/-2 cmH(2)O on the deflation limb. The difference between the Paw at minimal OI and Paw(optimal) was -1.9+/-4.2 cmH(2)O (NS) during inflation and -1.5+/-1.6 cmH(2)O (p<0.05) during deflation. In 15 out of the 16 comparisons, the difference in Paw was within one step (+/-3 cmH(2)O). The minimal OI is indicative for the Paw where oxygenation is optimal during HFOV in surfactant-depleted pigs.