TNF and Acidosis: Risk factors for development of ARDS included elevated serum level of HSP-70 >5.5 ng/ml (OR:10.5; 95% CI: 4.081–27.018), elevated TNF-a >442 pg/ml (OR: 6; 95% CI: 2.997–12.011.997.011), bacterial biofilm formation (OR: 7.273; 95% CI; 1.983–26.948.983.948), respiratory acidosis (OR:6; 95%CI:2.438–14.766.438.766), and low PaO2/FiO2 <300 (OR:1.667; 95% CI:1.313–2.116.313.116) as shown in Table 6.