X3.2 Non-invasive positive pressure ventilation

Non-invasive positive pressure ventilation is effective for acute hypercapnic ventilatory failure (Ram et al., 2004) [evidence level I]

Ventilatory support with intermittent positive pressure ven­tilation (IPPV) should be considered in patients with rising Paco₂ levels who are unable to ventilate adequately (ie, acute or acute-on-chronic respiratory acidosis). (Meyer and Hill, 1994, Bott et al., 1993, Brochard et al., 1995, Kramer et al., 1995, Plant et al., 2000) This can be achieved non-invasively (by means of a face mask, NIPPV) or invasively through an endotracheal tube. (Rossi et al., 1985), (Esteban et al., 2000)

NIPPV is an effective and safe means of treatment of ventilatory failure. Its use allows preservation of cough, physiological air warming and humidification, and normal swallowing, feeding and speech. Early intervention with NIPPV is suggested when the respiratory rate is more than 30 per minute and blood pH is less than 7.35. An improvement in respiratory rate and pH usually occurs within one hour of starting NIPPV. (Meyer and Hill, 1994, Bott et al., 1993, Brochard et al., 1995, Kramer et al., 1995, Plant et al., 2000) Failure to respond or further deterio­ration would indicate a need to consider intensive care unit admission (see Box 11).

Applying non-invasive ventilation in addition to conven­tional therapy reduces mortality (Relative Risk 0.5), and the need for intubation (RR 0.4) and its potential complications. NIPPV results in more rapid improvements in respiratory rate, dyspnoea score and blood gas abnormalities than conventional therapy alone. Some studies have also shown an improvement in survival and a reduced length of stay in hospital (Weighted Mean Difference 3.24 days)(Ram et al., 2004) [evidence level I].