Methods and apparatus for heart failure treatment

Abstract

Methods and apparatus for assessing the condition of and treating patients for heart failure by the delivery of continuous positive airway pressure are disclosed. Treatment of obstruction due to reflex vocal cord closure often experienced by heart failure patients is distinguished from treatment of upper airway obstruction typically associated with Obstructive Sleep Disorder. Treatment may also be implemented by delivering synchronized cardiac pressure oscillations superimposed on a respiratory pressure level to provide assistance for the heart. Heart treatment pressure dose indicator may be calculated for prescribing and monitoring the delivery of treatment. The apparatus may also generate data to track heart failure condition that may be indicative of the degree of severity of heart failure based upon breathing patterns to assist in the diagnosis and management of heart failure patients.

1 - 120 . (canceled)  
   
   
       121 . An apparatus for evaluation of heart failure in a patient comprising: 
 a means for supplying a controllable level of breathable gas to a patient at a pressure above atmospheric;    a flow sensor to generate a flow signal indicative of the patient's airflow; and a controller to process said flow signal and control said means for supplying wherein said controller is adapted and configured for:    delivering breathable gas at a pressure above atmospheric to a patient with said means for supplying; and    calculating a heart failure indicator from said flow signal, said heart failure indicator representing information about the patient's condition.    
   
   
       122 . The apparatus of  claim 121  wherein said calculating includes analyzing said airflow to determine an extent of Cheyne-Stokes breathing of the subject.  
   
   
       123 . The apparatus of  claim 122  wherein the controller is further configured and adapted for prompting for heart failure monitoring characteristics and recording said heart failure monitoring characteristics and said heart failure indicator in a memory.  
   
   
       124 . The apparatus of  claim 123  wherein one of said heart failure monitoring characteristics is a level of B natriuretic peptide.  
   
   
       125 . The apparatus of  claim 122  wherein the controller is further configured and adapted for controlling a step of identifying subsequent heart failure treatment based at least in part upon said heart failure indicator.  
   
   
       126 . The apparatus of  claim 125  wherein said subsequent heart failure treatment is an increase in the pressure of the breathable gas.  
   
   
       127 . The apparatus of  claim 122  wherein the controller is further configured and adapted for controlling comparing said heart failure indicator to a prior heart failure indicator determined during a previous treatment session.  
   
   
       128 . The apparatus of  claim 122  wherein the controller is further configured and adapted for reducing said pressure during a detected episode of Cheyne-Stokes breathing for a predetermined period of time to permit a determination of said heart failure indicator from said predetermined period of time such that a pattern of Cheyne-Stokes breathing can emerge without significant influence from treatment pressure.  
   
   
       129 . The apparatus of  claim 122  wherein said calculating comprises analyzing said airflow to determine a duration of a waxing and waning cycle.  
   
   
       130 . The apparatus of  claim 125  wherein said controller is further configured and adapted for analyzing said heart failure indicator as a function of a threshold value.  
   
   
       131 . The apparatus of  claim 125  wherein said indicator is a function of a measure of ventilation.  
   
   
       132 . The apparatus of  claim 125  wherein said controller is further configured and adapted for analyzing said heart failure indicator to determine a change in said heart failure indicator over time.  
   
   
       133 . The apparatus of  claim 132  wherein said change is a difference between a previous heart failure indicator and a subsequent heart failure indicator.  
   
   
       134 . The apparatus of  claim 128  wherein said change is a ratio of a previous heart failure indicator and a subsequent heart failure indicator.  
   
   
       135 . The apparatus of  claim 128  wherein said controller is further configured and adapted for generating a warning signal as a function of said change from said step of analyzing.  
   
   
       136 . The apparatus of  claim 135  wherein said warning signal triggers an audible alarm in said device.  
   
   
       137 . The apparatus of  claim 122  wherein said calculating comprises a frequency analysis of said airflow in a range of frequencies indicative of Cheyne-Stokes breathing cycle.  
   
   
       138 . The apparatus of  claim 137  wherein said frequency analysis of said airflow is in a range of about 1/20 hertz to 1/90 hertz.  
   
   
       139 . The apparatus of  claim 138  wherein said heart failure indicator includes a magnitude of a component of said airflow at a frequency in said range.  
   
   
       140 . The apparatus of  claim 139  wherein said heart failure indicator is a sum of magnitudes of components of said airflow in a sub-range of frequencies in said range.  
   
   
       141 . The apparatus of  claim 140  wherein said frequency analysis of said airflow is performed with data sampled from a measure of ventilation derived from said airflow.  
   
   
       142 . The apparatus of  claim 141  wherein said measure of ventilation is a minute volume.  
   
   
       143 . The apparatus of  claim 139  with further instructions for controlling a step of comparing said magnitude with a threshold value.  
   
   
       144 . The apparatus of  claim 143  wherein said threshold value is a magnitude derived from a previous frequency analysis.  
   
   
       145 . The apparatus of  claim 122  wherein said indicator is a measure of ventilation.  
   
   
       146 . The apparatus of  claim 145  wherein said measure of ventilation is a threshold of about 15 L/min.  
   
   
       147 . The apparatus of  claim 122  wherein said indicator is a ratio of a minimum ventilation and a maximum ventilation.  
   
   
       148 . The apparatus of  claim 147  wherein the minimum ventilation and maximum ventilation are derived from a measure of minute ventilation.  
   
   
       149 . The apparatus of  claim 147  wherein the minimum ventilation and maximum ventilation are derived from a measure of tidal volume.  
   
   
       150 - 178 . (canceled)