TY - JOUR
T1 - Orthopnea and inspiratory effort in chronic heart failure patients
AU - Nava, Stefano
AU - Larovere, M. Teresa
AU - Fanfulla, F.
AU - Navalesi, P.
AU - Delmastro, M.
AU - Mortara, A.
PY - 2003/6/1
Y1 - 2003/6/1
N2 - Study objective: Orthopnea is a typical feature of patients with chronic heart failure (CHF), the factors contributing to it are not completely understood. We investigated changes in dyspnea and other respiratory variables, induced by altering posture (from sitting to supine) in II CHF patients (NYHA classes II-IV) and 10 control subjects. Methods and Results: We measured dyspnea (Borg scale), the diaphragm pressure time product per minute (PTPdi/m, index of metabolic consumption), and mechanical properties of the lung (lung compliance (C,L) and resistances (R,L). CHF patients also underwent a trial of non-invasive mechanical ventilation (NIMV) inthe supine position in order to ascertain whether unloading the inspiratory muscles could somehow relieve dyspnea. While sitting the PTPdi/min was significantly higher in CHF patients than in controls (181±54 cm H2O × s/min vs. 96±32; P<0.05). Assuming a supine position caused no major changes in controls, whereas CHF patients showed a significant worsening in dyspnea, a rise in PTPdi/min (243±97 p<0.01) and R,L (4.7±1.2 cm H2O/L × s sitting vs. 79±2.5 supine; P<0.01) and a decrease in C,L (0.08±0.02 L/cm H2O sitting vs. 0.07+0.01 supine; P<0.05). Applying NIMV to supine CHF patients significantly reduced the PTPdi/min to 81±42 (P<0.001). Changes in dyspnea, produced by varying position or applying NIMV, were significantly correlated with PTPdi/min (r=0.80, P<0.005 and r=0.58, P<0.01, respectively). Conclusions: CHF patients had a higher PTPdi/min than controls when sitting, and assuming a supine position induced severe dyspnea, a large rise in R,L, and a reduction in C,L so that PTPdi/min increased further. Orthopnea was strongly correlated with the increased diaphragmatic effort.
AB - Study objective: Orthopnea is a typical feature of patients with chronic heart failure (CHF), the factors contributing to it are not completely understood. We investigated changes in dyspnea and other respiratory variables, induced by altering posture (from sitting to supine) in II CHF patients (NYHA classes II-IV) and 10 control subjects. Methods and Results: We measured dyspnea (Borg scale), the diaphragm pressure time product per minute (PTPdi/m, index of metabolic consumption), and mechanical properties of the lung (lung compliance (C,L) and resistances (R,L). CHF patients also underwent a trial of non-invasive mechanical ventilation (NIMV) inthe supine position in order to ascertain whether unloading the inspiratory muscles could somehow relieve dyspnea. While sitting the PTPdi/min was significantly higher in CHF patients than in controls (181±54 cm H2O × s/min vs. 96±32; P<0.05). Assuming a supine position caused no major changes in controls, whereas CHF patients showed a significant worsening in dyspnea, a rise in PTPdi/min (243±97 p<0.01) and R,L (4.7±1.2 cm H2O/L × s sitting vs. 79±2.5 supine; P<0.01) and a decrease in C,L (0.08±0.02 L/cm H2O sitting vs. 0.07+0.01 supine; P<0.05). Applying NIMV to supine CHF patients significantly reduced the PTPdi/min to 81±42 (P<0.001). Changes in dyspnea, produced by varying position or applying NIMV, were significantly correlated with PTPdi/min (r=0.80, P<0.005 and r=0.58, P<0.01, respectively). Conclusions: CHF patients had a higher PTPdi/min than controls when sitting, and assuming a supine position induced severe dyspnea, a large rise in R,L, and a reduction in C,L so that PTPdi/min increased further. Orthopnea was strongly correlated with the increased diaphragmatic effort.
KW - CHF
KW - Diaphragm
KW - Dyspnea
KW - Inspiratory muscle
KW - Non-invasive ventilation
UR - http://www.scopus.com/inward/record.url?scp=0038312903&partnerID=8YFLogxK
U2 - 10.1053/rmed.2003.1495
DO - 10.1053/rmed.2003.1495
M3 - Article
SN - 0954-6111
VL - 97
SP - 647
EP - 653
JO - Respiratory Medicine
JF - Respiratory Medicine
IS - 6
ER -