Nasal intermittent positive pressure ventilation in acute exacerbations of chronic obstructive pulmonary disease — a preliminary study

Ten patients (two male) suffering from acute exacerbations of long-standing chronic obstructive pulmonary disease and admitted in hypoxic, hypercapnic respiratory failure were treated with Nasal Intermittent Positive Pressure Ventilation (NIPPV) plus supplemental oxygen, on a general medical ward. The median (range) pH on admission was 7·30 (7·20–7·35), the median age was 67 years (47–77) with an FEV 1 (percent of predicted) of 30 (17–39). On admission the median arterial oxygen tension ( PaO 2) was 4·71 kPa (3·45–6·26) on air, and the carbon dioxide tension ( PaCO 2) was 7·68 kPa (6·85–9·83). With controlled oxygen therapy there was no significant improvement in PaO 2, but the median PaCO 2 increased significantly to 9·75 kPa (7·04–11·70) ( P < 0·05). By using NIPPV with supplemental oxygen it was possible to significantly improve the median PaO 2 to 11·25 kPa (6·70–26·90) ( P < 0·01) without worsening PaCO 2 levels (8·96 kPa; 6·85–13·10). NIPPV was applied by a senior, respiratory physiotherapist and used intermittently depending on patient tolerance and clinical response. The median total time on NIPPV was 27 h, delivered over 1–5 days. One patient found the mask difficult to tolerate beyond a short period of time. NIPPV was well accepted on a general ward by nursing staff. Three patients later died with progressive hypercapnia, despite an initial response; with one of these patients also receiving intubation and mechanical ventilation. A further patient also received intubation and mechanical ventilation and was eventually discharged. NIPPV plus supplemental oxygen offers a method to correct hypoxaemia on a general medical ward without worsening hypercapnia for acute on chronic, hypoxic, hypercapnic respiratory failure, and warrants further investigation.