الفهرس 
Physiological Respiratory ConsiderationsOnly 14 pages are availabe for public view
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Abstract
Acute respiratory distress syndrome (ARDS) is a respiratory disorder characterized by fluid accumulation in the lung alveoli (non-cardiogenic pulmonary edema) that leads to severe respiratory failure making the patient more prone to mechanical ventilation.
The diagnosis of ARDS depends mainly on immunological bases as many inflammatory mediators may be increased at the early stages of ARDS; IL6 is one of them and could be considered as early biomarker for ARDS progress.
Systemic endothelial activation and injury are important features of ARDS, so plasma levels of von Willebrand factor (VWF), a marker of endothelial activation and injury, would be expected to be associated with early diagnosis and clinical progress of acute respiratory distress syndrome (ARDS).
The primary objective of this study was to test the hypothesis that Von Willebrand factor is an important determinant of early detection of acute respiratory distress syndrome in comparison to interleukin 6 (an early predictor cytokine of A.R.D.S).
After obtaining approval of the institutional ethics committee, sixty critically ill patients were randomly chosen to be enrolled in this study.
Patients should have one or more risk factor for development of acute respiratory distress syndrome either in the form of direct lung injury causes e.g.: (severe pneumonia (infection), aspiration pneumonitis, inhalation lung injury, severe trauma to the chest) or Indirect lung injury causes e.g. ( systemic sepsis , severe injury or trauma, incompatible blood transfusion TRALI (transfusion related acute lung injury), acute pancreatitis , fracture of the long bones ,near drowning ,anaphylaxis, uremia ,fat embolus )
On the start of the study demographics, age, sex, weight, APACHEII score and cause of admission recorded. Patients were monitored using ECG non-invasive, invasive blood pressure monitoring, and Spo2 using pulse oximetry.
Also the whole study patients were subjected to the following : clinical parameter: complete general examination and recording of data of admission, laboratory parameter: CBC, renal function test, liver function tests, hematologic assessment, coagulation profile)and radiological parameter: chest Xray with calculation of Murry score of the lung injury, ECG and echocardiography for some patients according to the clinical condition, In addition to: measurements of respiratory parameter: respiratory rate- ABG -arterial oxygen parameters.
Levels of both VWF and IL.6 measured on T=0 i.e. (at start of the study once the patient considered to be risky for A.R.D.S to obtain their baseline levels), T=48 (after two days), and T=72 (after three days), significant correlations between VWF & IL6 concentrations during the study and the development of A.R.D.S were analyzed.
Factors that may affect the levels of both VWF and IL6 were also evaluated as platelets &leucocytic counts, PTT& INR values, renal and liver functions parameters as well as respiratory parameters, and they all showed absence of any significant correlation between them and VWF &IL6 different levels.
Thirty nine patients of the whole patients developed ARDS (group I) 65% of total number of studied patients and twenty one patients did not developed ARDS (group II) 35% of total number of studied patient.
During the study period, mean plasma vWF levels were elevated in both groups however it elevated more in the A.R.D.S group I than the other group (non ARDS group II) 420.5 ± 80.48 vs. 284.57 ± 98.99 at T=0, 483.26 ± 77.86vs. 338.62 ± 92.68 at T=48 and 548.03 ±69.59vs. 388 ± 88.34 at T=72 with P value < 0.01.
Statistical analysis revealed, strong association between vWF different levels and ARDS development, as vWF nearly reached to the well-known cut off value of 450 pg/ml that documented by the previous studies, in the present study we recorded plasma vWF cut off value 447 pcg ∕ml on the 3rd day of ARDS development prediction period with a sensitivity of 94.9% & specificity of 56.7% for predicting ARDS development, In comparison to IL6 which showed a sensitivity of 93.8% & specificity of 52.4% at cut off value 234 pcg ∕ml during the same period.
Based on those correlations the present study supports the previous observations that VWF plasma level is beneficial biomarker for early diagnosis of ARDS development with a higher sensitivity and specificity in comparison to IL6.