Figure 1. A normal minute ventilation involves a minute ventilation between 5 and 8 L [ie, 500–600 mL, rate 10–14 breaths/minute]. In severely ill COPD and asthma patients, overventilation risks auto-PEEP and barotrauma; a starting rate of six breaths with a 500 mL volume allows maximum time for exhalation. Closely monitor blood pressure and vent pressures for auto-PEEP, and adjust up minute ventilation as tolerated. In severely acidotic patients who must maintain a compensatory respiratory alkalosis, match preprocedural minute ventilation during the onset phase of muscle relaxants and after intubation.