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 FEV1 (percent of predicted) of 30 (17-39). On admission the median arterial oxygen tension (PaO2) was 4.71 kPa (3.45-6.26) on air, and the carbon dioxide tension (PaCO2) was 7.68 kPa (6.85-9.83). With controlled oxygen therapy there was no significant improvement in PaO2, but the median PaCO2 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 PaO2 to 11.25 kPa (6.70-26.90) (P < 0.01) without worsening PaCO2 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.