Introduction:
Various types of abnormal breathing including Cheyne-Stokes respiration are frequently observed in patients with heart failure (HF). Although abnormal breathing is recognized as an indicator of poor prognosis, it has not been quantitatively evaluated. Therefore, we proposed a novel method for quantifying respiratory instability during abnormal breathing in patients with HF, and evaluated acute effect of adaptive servo-ventilation (ASV).
Methods:
Diurnal respiratory waveform during wakefulness was obtained by nasal pressure sensor (SAS-3200, Nihon Kohden) for 15 minutes. Analysis method for respiratory waveform was as follows. The inspiration slope (IS) was calculated as the ratio of the peak inspiratory amplitude over time-interval from peak expiration to peak inspiration, and interquartile ranges (IQR) of all consecutive ISs during 15-min were evaluated (Figure, top). Heart failure patients with abnormal breathing have breath-by-breath change in IS and therefore have high IQR score (e.g., Figure bottom left). Firstly, we compared IQR in five healthy volunteers (age 36 +/- 3) and 16 patients with HF (age 66 +/- 17 years old, NYHA 3.3 +/- 0.6, LVEF 31 +/- 12%). Secondly, we compared IQR in all 16 patients with HF during spontaneous respiration and ASV (e.g., Figure bottom right).
Results:
IQR in healthy volunteers were significantly lower compared with patients with HF (0.11 +/- 0.05 vs. 0.29 +/- 0.15, p<0.01). In patients with HF, ASV reduced IQR (0.29 +/- 0.15 vs. 0.14 +/- 0.10, p<0.01 vs spontaneous respiration).
Conclusions:
This novel method effectively quantified respiratory instability in HF patients. This quantitative evaluation method of respiratory instability may become one of the heart failure management tools.
Adaptive Servo-Ventilation Has More Favorable Acute Effects on Hemodynamics Than Continuous Positive Airway Pressure in Patients With Heart Failure
