Objective To explore the effects of lateral position ventilation on lung volume and oxygenation in patients with acute respiratory distress syndrome ( ARDS) . Methods Fourteen patients with ARDS were enrolled. Supine position, lateral position and supine position were successively adopted and continued for one hour respectively. End-expiratory lung volume ( EELV) was measured at the end of each epoch. Effects of different position on gas exchange, lung mechanics and hemodynamics were monitored.Results EELV was increased from ( 1109 ±321) mL to ( 1376 ±381) mL after lateral ventilation ( P lt;0. 05) , and decreased to ( 1143 ±376) mL after the second supine ventilation ( P lt;0. 05) . Compared with initial supine ventilation, there was no significant difference in EELV after the second supine ventilation( P gt;0. 05) . PaO2 /FiO2 was increased from ( 154. 3 ±35. 0) mm Hg to ( 189. 9 ±60. 1) mm Hg after lateral ventilation ( P lt;0. 05) , and increased to ( 209. 2 ±75. 4) mm Hg after the second supine ventilation ( P lt; 0. 05) . Compared with initial supine ventilation, PaO2 /FiO2 was increased greatly after the secondsupine ventilation ( P lt; 0. 01) . There was no significant difference in PaCO2 , lung mechanics and hemodynamics after changing different position. Conclusion Lateral position ventilation can increase EELV and improve oxygenation in patients with ARDS.
Objective To investigate whether the new oxygenation index [ PaO2 /( FiO2 ×Paw ) ]which including mean airway pressure ( Paw ) for assessing intrapulmonary shunting of acute respiratory distress syndrome( ARDS) could be more accurate than the conventional oxygenation ratio ( PaO2 /FiO2 ) .Methods Twelve patients with ARDS were recruited. All patients received mechanical ventilation under lung ventilation protective strategy ( VT 6 mL/kg, f 16 bpm, FiO2 60% ) , and had a Swan-Ganz catheter inserted. Then, pressure/ volume curves were determined by low-flow method and the lower inflection point pressure was surveyed. Subsequently, parameters of respiratory mechanics and haemodynamics were recorded while periphery and pulmonary artery blood gas analysis were performed when positive end expiratory pressure ( PEEP) were changed. PaO2 /FiO2 and Qsp/Qt were calculated through special formula respectively. Results The progressive PEEP could not change Cst, PaO2 /FiO2 , and PaO2 / ( FiO2 ×Paw) in patients with ARDS significantly ( P gt; 0. 05) . The progressive PEEP did not change Qsp/Qt significantly ( P gt;0. 05) . The Δz which was used to test the difference between the correlation coefficient of Qsp/Qt and PaO2 / ( FiO2 ×Paw) and the correlation coefficient of Qsp/Qt and PaO2 /FiO2 was 0. 571, and there was no difference between the two correlation coefficients ( P gt; 0. 05) . It was not Paw but Cst which impacted on Qsp/Qt and PaO2 /FiO2 . Conclusion PaO2 / ( FiO2 × Paw ) is equal to PaO2 /FiO2 in assessing intrapulmonary shunting of ARDS.
Objective To explore the prognostic significance of baseline clinical and pulmonary physiological variables on idiopathic pulmonary fibrosis ( IPF) . Methods Patients diagnosed with IPF according to 2011 ATS/ERS/JRS/ALAT statementwere selected from Nanjing DrumTower Hospital between January 1, 2002 and July 31, 2010. The baseline characteristics were abstracted, including age, gender, smoking history, corticosteroid, delay before diagnosis, body mass index, finger clubbing, oxygenation index ( PaO2 /FiO2 ) , C-reaction protein, erythrocyte sedimentation rate ( ESR) , serum lactate dehydrogenase ( LDH) , albumin, vital capacity ( VC) , forced vital capacity ( FVC) , total lung capacity ( TLC) , and singlebreath diffusing capacity of the lung for carbon monoxide ( DLCO) . The relationships between all factors and survival were examined with a univariate Cox proportional-hazard model. Kaplan-Meier method was used to assess the survival probabilities between groups with different baseline characteristics. Results Eighty-four patients were included in this study, with the median survival time of 34. 7 months. PaO2 /FiO2 , FVC% pred, VC% pred, TLC% pred, and DLCO% pred showed significant associations with the mortality of IPF ( hazard ratios 0. 940-0. 994, P lt; 0. 01) . The Kaplan-Meier analyses for above variables also showed significant differences ( P lt;0. 05) . Besides, the statistical difference of survival probability could be found between the patients with elevated serumLDH and those with normal LDH ( 27. 0 months vs. 43. 1 months, P =0. 014) . Conclusions Baseline oxygenation and pulmonary function parameters may indicate the prognosis of IPF patients. Serum LDH may provide clinicians with additional prognostic information.