Physiological and symptom effects of changing posture from sitting to supine, and vice versa, in stable chronic heart failure

Objective The current study aimed to evaluate the effects of supine position in stable chronic heart failure (CHF) patients with systolic dysfunction, their relationship with dyspnoea and differences in NYHA classes.Methods In 17 CHF male patients (61 +/- 8 y, NYHA class II 18 NYHA classes III and IV 9) admitted to hospital for clinical stabilization and rehabilitation scopes we measured oxygenation, respiratory mechanics, dynamic lung volumes, haemodynamics, and dyspnoea in sitting vs supine posture (randomized order) when in stable state condition.Results Compared to sitting, supine posture decreased oxygenation and maximal oesophageal swing, increased oesophageal pressure swing, respiratory drive normalized for maximal inspiratory strength, pressure time index, pulmonary artery pressure, transmural pulmonary artery pressure (TM-PAP) and transmural pulmonary artery occlusion pressure (TM-PAOP) (all P < 0.01). The decline in TM-PAP (P=0.0195) and TM-PAOP (P = 0.0421) was significantly greater in New York Heart Association class II than III-IV patients. Delta variation in dyspnoea related only with supine value of TM-PAOP and delta change of TM-PAOP (R = - 0.53 and P < 0.0277; R = 0.56 and P < 0.0175, respectively).Conclusions In stable CHF patients with systolic dysfunction, supine position is associated with a worsening of oxygenation, respiratory mechanics and haemodynamics but not dyspnoea; patients with less severe heart failure show a greater worsening of transpulmonary pressures. Sensation of dyspnoea seems, at least in part, independent of worsening of cardiac and pulmonary functions