The Value Of PaO₂/(FiO₂ X P(?)) In Assessing Intrapulmonary Shunting Of Acute Respiratory Distress Syndrome

Objective To study the value using the new oxygenation index [PaO₂/(FiO₂ x P(?))] combining mean airway pressure (Paw) for assessing intrapulmonary shunting in animal model made acute respiratory distress syndrome CARDS) .Methods Initially 8 landrace piglets were administered to provide anaesthesia, then, all piglets were required mechanical ventilation, had a Swan Ganz catheter, consecutive intravenously injected Escherichia coli 055;B5 and successfully made ARDS model. Subsequently, the parameters of respiratory mechanics and the results of blood gas analysis were recorded when the conditions of positive end expiratory pressure were changed; PaO₂/(FiO₂ x P(?)), the conventional oxygenation ratio (PaO₂/FiO₂) and intrapulraonary shunting (Qsp/Qt) were respectively calculated through special formula. Finialy, all data were progressed statistical analysis.Results1, the influencing oxygenation factor analysis:â‘ The correlation coefficient between PaO₂/FiO₂ and PEEP was 0.241, there was incorrelate (P>0.05) [Table13].â‘¡The correlation coefficient between PaO₂/FiO₂ and Peak Inspiratory Pressure (PIP ) was 0.312, there was positive correlation (P<0.05) [Table13].â‘¢The correlation coefficient between PaO₂/FiO₂ and Plat Pressure(Pplat) was 0.227,there was incorrelation (P>0.05 ) [Tablel3].â‘£The correlation coefficient between PaO₂/FiO₂ and P(?) was 0.343,there was positive correlation (P<0. 05) [Table13].⑤The correlation coefficient between PaO₂/FiO₂ and Static Compliance (Cst) was 0.284, there was positive correlation (P<0. 05) [Table13].2, The correlation between PaO₂/(FiO₂ x P(?)), PaO₂/FiO₂ and Qsp/Qtanalysis: â‘ The correlation coefficient between PaO₂/(FiO₂ x P(?)) and Qsp/Qt was -0.492, there was significant negatively linear relationship (P<0.01) [Table16].â‘¡The correlation coefficient between PaO_/FiO and Qsp/Qt was -0.560, there was significant negatively linear relationship (P<0.01) [Table16].Conclusion the major factor of improving oxygenation was Paw ; PaO₂/(FiO₂ x P(?)) unifying Paw was equal or better in assessing intrapulmonary shunting of ARDS than PaO₂/FiO₂ .