Assisted ventilation in acute exacerbation of chronic obstructive pulmonary disease

In the UK, over three million people suffer from COPD, and over 30,000 people die as a result each year. Acute exacerbations of COPD are a particularly heavy burden to patients, and to the Health Service. Patients often present with AHRF, and this presentation accounts for 20% of all COPD admissions. Non-invasive ventilation is of proven efficacy in the management of AHRF associated with an exacerbation of COPD. Systematic reviews and metaanalysis have shown that the use of NIV in addition to standard medical therapy significantly reduces in-hospital mortality, the need for invasive ventilation, and the length of stay in hospital, when compared with standard medical therapy alone. Non-invasive ventilation is associated with greater improvements at one hour in pH, PaCO2, and respiratory rate. Ideally, patients who require NIV should be able to protect their airway, be cooperative with (and tolerant of) the technique, and be otherwise medically stable. It must be remembered that COPD with AHRF patients who survive treatment with NIV have a high risk of subsequent death and life-threatening events. At the same time the reported outcome for patients admitted with AHRF secondary to COPD tends to be worse in the group not treated with NIV. However, it is not sufficiently poor to render IMV inappropriate for COPD populations as a whole. A decision on the appropriateness of intubation and mechanical ventilation if NIV fails should be taken before NIV is initiated and this decision should be taken by senior medical staff with input from a critical care physician if necessary. Noninvasive ventilation should not be used as a substitute for tracheal intubation when the latter intervention is clearly more appropriate. In addition, it is suggested that patients with a pH <7.25, or who are candidates for intubation, should be managed on ITU if at all possible, and should certainly have critical care input in their management.