The frequency of invasive mechanical ventilation in patients with an acute exacerbation of chronic obstructive pulmonary disease (COPD) varies among studies [1,2]. The variable estimates reflect the different patient populations and definitions of exacerbation included in the studies. Invasive mechanical ventilation is associated with increased ICU mortality and hospital mortality, although the cause of mortality appears to be related to the severity of the underlying disease and not mechanical ventilation per se.
Invasive mechanical ventilation for patients with an acute exacerbation of COPD is discussed in this topic review. Noninvasive positive pressure ventilation (NPPV) is reviewed separately. (See "Noninvasive positive pressure ventilation in acute respiratory failure in adults".)
We believe the decision to institute mechanical ventilation should be based on clinical judgment that integrates many clinical variables. As an example, the precipitating illness and its rate of progression should be considered, as well as the patient's symptoms, signs, cardiopulmonary reserve, and comorbidities. Some clinicians advocate specific physiologic measures as indications for mechanical ventilation, but these have never undergone rigorous or systematic evaluation.
Deteriorating gas exchange unresponsive to conservative measures and respiratory distress are the most common reasons for mechanical ventilation in patients with acute respiratory failure due to COPD exacerbation [3-7]. Specifically:
- Hypoxemia that has not corrected with supplemental oxygen delivered by either a nasal cannula or a face mask.
- Severe respiratory acidosis, usually due to the precipitating illness or the injudicious administration of oxygen. (See "Use of oxygen in patients with hypercapnia".)
- Clinical manifestations of distress including severe dyspnea, tachypnea, nasal flaring, accessory muscle recruitment, tracheal tugging, recession of the suprasternal and intercostal spaces, pulsus paradoxus, diaphoresis, and paradoxic motion of the rib cage and abdomen .