Slow a and ffast c changes iin ttransmural p pulmonary a artery p pressure iin obstructive s sleep a apnoea

Slow and fast changes in transmural pulmonary artery pressure in obstructive sleep apnoea. O. Marrone, M.R. Bonsignore, S. Romano, G. Bonsignore.  ERS Journals Ltd 1994. ABSTRACT: Our purpose was to assess how pulmonary artery pressure changes in relation to hypoxia and oesophageal pressure during obstructive sleep apnoeas. Transmural systolic pulmonary artery pressure (Ppa,STM), oxyhaemoglobin satu- ration (SaO2) and oesophageal pressure were analysed in two samples of consecu- tive obstructive apnoeas in each of four patients. In the first samples (samples A; probably recorded during non-rapid eye move- ment (NREM) sleep), SaO2 swings were small and repetitive. In the second sam- ples (samples B; probably recorded during rapid eye movement (REM) sleep), they were large and more variable. Oesophageal pressure oscillated similarly in the two groups of samples. In all cases, transmural systolic pulmonary artery pressure progressively increased throughout apnoeas, and subsequently dec- reased in the interapnoeic periods. However, both early and end-apnoeic trans- mural systolic pulmonary artery pressure, remained stable in samples A; whilst they progressively increased in samples B. Transmural systolic pulmonary artery pressure at the beginning of each apnoea was inversely correlated with SaO2 at the end of the preceding apnoea. These results suggest that transmural systolic pulmonary artery pressure is influenced by SaO2, but does not vary at the same speed as SaO2. In all cases, beat-by-beat analysis showed, as expected, that the lower the oesophageal pressure, the higher the transmural systolic pulmonary artery pressure however, at each oesophageal pressure level, transmural systolic pulmonary artery pressure was more variable and higher, in samples B. In conclusion, transmural systolic pulmonary artery pressure in obstructive apnoeas shows rapid changes, which reflect oesophageal pressure variations, and slower changes, which are likely to be caused by SaO2.