Invasive Ventilation

Intubation should be considered in patients with the following.

• NPPV failure: worsening of arterial blood gases and or pH in 1-2 h; lack of improvement in arterial blood gases and or pH after 4 h.
• Severe acidosis (pH <7.25) and hypercapnia (Pa,CO₂ >8 kPa (60 mmHg)).
• Life-threatening hypoxaemia (arterial oxygen tension/inspiratory oxygen fraction <26.6 kPa (200 mmHg)).
• Tachypnoea >35 breaths·min-1.
• Other complications: metabolic abnormalities, sepsis, pneumonia, pulmonary embolism, barotrauma, massive pleural effusion [17].

NPPV should be considered as the first-line intervention, in addition to optimal mechanical therapy, for the management of patients with respiratory failure due to exacerbation of COPD [4]. In the first few hours NPPV requires the same level of assistance as conventional mechanical ventilation [20].

A recent study has clearly stated that NPPV is highly cost effective [21]. In patients who need intubation, NPPV can be considered as a potential successful strategy for weaning [22]. It can also be considered in patients with previous persistent weaning failure [23].

Figure 2 illustrates a possible "flow-chart" for the use of NPPV in exacerbation of COPD complicated by acute respiratory failure.

Fig. 2. - Flow-chart for the use of noninvasive positive pressure ventilation (NPPV) during exacerbation of chronic obstructive pulmonary disease (COPD) complicated by acute respiratory failure. MV: mechanical ventilation; Pa,CO₂: arterial carbon dioxide tension.