Clinical and scientific letters: The national early warning score gives misleading scores for oxygen saturation in patients at risk of hypercapnia.

Table 1. Application of the oxygen section of the NEWS chart to 400 routine observations rounds for 22 patients on a respiratory ward with target oxygen saturation range of 88–92%. SpO2 Number of observations (%) Number with appropriate oximetry score in NEWS (%) Satisfactory 350 (87.5) > 270 had saturation within target range > 80 had saturation >92% breathing air 22/350 (6.3) > 22 had SpO2 ≥96% breathing air > 328 scored ‘too low’ in NEWS <88% 10 (2.5) 10/10 (100.0) All scored 3 points for hypoxaemia >92% breathing oxygen 40 (10.0) 0/40 (0.0) 34/40 scored ‘too low’ in NEWS Total 400 (100.0) 32/400 (8.0) In total, 19 patients had chronic obstructive pulmonary disease and three had complex lung disease with hypercapnia. NEWS = national early warning score; SpO2 = oxygen saturation.