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document
The effect of posture on Cheyne-Stokes respirations and hemodynamics in patients with heart failure . STUDY OBJECTIVES Cheyne-Stokes respirations occur in 40 % of patients with heart failure . Orthopnea is a cardinal symptom of heart failure and may affect the patient 's sleeping angle . The objective of this study was to assess the respiratory and hemodynamic response to sleeping angle in a group of subjects with stable heart failure . DESIGN Twenty-five patients underwent overnight polysomnography with simultaneous and continuous impedance cardiographic monitoring . Sleeping polysomnographic and impedance cardiographic data were recorded . SETTING The study was conducted in a sleep center . PATIENTS All 25 patients had clinically stable heart failure and left ventricular ejection fractions < 40 % . INTERVENTIONS The patients slept at 0 degrees , 15 degrees , 30 degrees , and 45 degrees in random order . MEASUREMENTS AND RESULTS Seventeen patients had Cheyne-Stokes apneas ( index > 5/h ) and 23 patients had hypopneas ( index > 5/h ) . The hypopnea index showed no response to sleeping angle . The Cheyne-Stokes apnea index decreased with increasing sleeping angle ( P < 0.001 ) . This effect was seen only during supine sleep and non-rapid eye movement sleep and was absent in non-supine sleep , rapid eye movement sleep , and during periods of wakefulness . Thoracic fluid content index and left ventricular hemodynamics measured by impedance cardiography showed no response to sleeping angle . CONCLUSIONS Changing the heart failure patient 's sleeping angle from 0 degrees to 45 degrees results in a significant decrease in Cheyne-Stokes apneas . This decrease occurs on a constant base of hypopneas . The changes in Cheyne-Stokes apneas are not related to changes in lung congestion and left ventricular hemodynamics .
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Intervention_Physical
posture
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Intervention_Physical
sleeping angle
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Intervention_Physical
slept at 0 degrees , 15 degrees , 30 degrees , and 45 degrees in random order .
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Outcome_Other
effect
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Outcome_Physical
assess the respiratory and hemodynamic response
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Outcome_Physical
Sleeping polysomnographic and impedance cardiographic data
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Outcome_Physical
Cheyne-Stokes apneas
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Outcome_Physical
hypopneas
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Outcome_Physical
hypopnea index
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Outcome_Physical
Cheyne-Stokes apnea index
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Outcome_Physical
Thoracic fluid content index and left ventricular hemodynamics
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Participant_Condition
heart failure
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Participant_Condition
heart failure
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Participant_Sample-size
Twenty-five
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Participant_Sample-size
25
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Participant_Condition
clinically stable heart failure
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Participant_Condition
ventricular ejection fractions < 40 %