Increase in work of breathing
Work of breathing in respiratory failure can account for 30% of total oxygen consumption. Respiratory support of some form (NIV, CPAP or invasive ventilation) will reduce this burden.
There may be advantages in early introduction of some form of respiratory support, particularly if total body oxygen consumption is greater than total body oxygen delivery.
Such an imbalance will produce low central or mixed venous oxygen saturation, a metabolic acidosis and perhaps an increase in lactate.