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 systolyc 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 systolyc pulmonary artery pressure increase, which is mainly due to hypoxic vasoconstriction.