Definition: Tidal Volume (Vt) 4-7 cc/kg predicted body weight, i.e., [50 (male) OR 45 (female) +0.91(ht in cm – 152.4)]
NHLBI: ARDS Network: Vt 6-8 cc/kg PBW AND Pplat <30 cm H20. PaO2 goal: 55-80mmHg. SpO2 goal: 88-95%. pH: 7.3-7.45.
Rationale: Decreases incidence of Ventilator-Induced Lung Injury (VILI) – barotrauma, atelectato-trauma and volu-trauma secondary to overstretching of alveoli and subsequent injury to lungs as evidenced by increased inflammatory markers (increased permeability, decreased surfactant). Decrease in morbidity and mortality and length of mechanical ventilation in patients with ARDS/ALI. Permissive hypercapnia associated with LTVV also contributes to protective lung ventilator strategy benefits: Acidosis attenuates inflammatory response, decreases neutrophil infiltration, improves tissue oxygenation and cardiac output.
Open Lung Concept: Recruit alveoli, prevent de-recruitment