An unusual increase in haemodynamic values in a sleep apnoea syndrome patient with prolonged apnoea.

This case report shows the results of a right heart catheterisation in a patient with sleep apnoea syndrome (SAS). Arterial oxygen saturation (SaO2), heart rate, oronasal flow, and monitoring of electroencephalographic (EEG), sovrayoidal electromyographic (EMG) and thoracoabdominal movements were recorded simultaneously. A mixed apnoea of 180 s was registered, SaO2 fell to 54\% and systolic pulmonary artery pressure (sPAP) increased to 130 mmHg. Slowly, haemodynamic values began to normalise with the reappearance of respiratory acts. We can hypothesize that this patient's nocturnal apnoeas may cause frequent and deep negative pleural pressure swings, with severe continuous action on pulmonary circulation. This case report has shown that a SAS patient is capable of developing an adaptative response to an unusual and remarkable systolic pulmonary artery pressure increase, which is mainly due to hypoxic vasoconstriction.