Measuring central pulmonary pressures during exercise in COPD: how to cope with respiratory effects

Abstract

Respiratory influences are major confounders when evaluating central haemodynamics during exercise. We studied four different methods to assess mean pulmonary artery pressure (mPAP) and pulmonary capillary wedge pressure (PCWP) in cases of respiratory swings.Central haemodynamics were measured simultaneously with oesophageal pressure during exercise in 30 chronic obstructive pulmonary disease (COPD) patients. mPAP and PCWP were assessed at the end of expiration, averaged over the respiratory cycle and corrected for the right atrial pressure (RAP) waveform estimated intrathoracic pressure, and compared with the transmural pressures.Bland-Altman analyses showed the best agreement of mPAP averaged over the respiratory cycle (bias (limits of agreement) 2.5 (-6.0-11.8) mmHg) and when corrected with the nadir of RAP (-3.6 (-11.2-3.9) mmHg). Measuring mPAP at the end of expiration (10.3 (0.5-20.3) mmHg) and mPAP corrected for the RAP swing (-9.3 (-19.8-2.1) mmHg) resulted in lower levels of agreement. The respiratory swings in mPAP and PCWP were similar (r 2 50.82, slope¡SE 0.95¡0.1). Central haemodynamics measured at the end of expiration leads to an overestimation of intravascular pressures in exercising COPD patients. Good measurement can be acquired even when oesopghageal pressure is omitted, by averaging pressures over the respiratory cycle or using the RAP waveform to correct for intrathoracic pressure. Assessment of the pulmonary gradient is unaffected by respiratory swings. @ERSpublications Measurement of intravascular pressures in exercising COPD patients requires correction for intrathoracic pressure

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“…In the latter case, for example, intrathoracic pressure fluctuations are exaggerated, which can lead to an underestimation of the mean PAWP value [14,43].…”

Nadciśnienie płucne w przebiegu chorób lewego serca — aktualne leczenie i kierunki rozwoju terapii

“…Wydaje się, że końcowowydechowe pomiary PAWP są lepsze do różnicowania między PAH i HFPEF, zaś wartości średnie są bardziej dokładne w grupie chorych z przewlekłą obturacyjną chorobą płuc (COPD, chronic obstructive pulmonary disease), u których wahania oddechowe są zwykle większe. W praktyce klinicznej błędnych klasyfikacji PH-LHD jako PAH i niewłaściwego leczenia tych pacjentów lekami celowanymi dla PAH jest istotnie więcej niż na odwrót [23,24].…”