CXCL8 and susceptibility to pneumonia measurement: The study showed reduced markers of lung inflammation (interleukin (IL) 1α, IL-1β, IL-8, IL-10, tumour necrosis factor α, macrophage inflammatory protein 1α, pulmonary and activation-regulated chemokine) in patients receiving CPAP (P < 0.05) but this did not translate into reduced pneumonia (RR 0.8, 95 per cent c.i. 0.27 to 2.41; P = 0.69).