[Effect of n-CPAP therapy on outcome of cold provocation]

Our own investigations comprising 23,174 patients suffering from sleep apnoea showed that about 4 per cent of these patients suffer from a hyperreactive bronchial system. In some of these patients treatment with nCPAP causes coughing or mild dyspnoea even after having been previously asymptomatic. Loss of water and heat on the surface of bronchial mucosa may induce reversible bronchoconstriction. We examined in 60 patients suffering from obstructive sleep apnoea whether mechanical treatment with nCPAP would cause a change in bronchial reactivity. Cold air hyperventilation was used in provocation testing. Provocation tests were performed before and after a 3-day treatment with nCPAP in the early morning. In some patients with previously positive reaction, application of nCPAP alone decreased the lung function. Cold air hyperventilation challenge may be helpful to detect possible risks in patients using nCPAP, and to minimise such risks.