Leg Fluid Shift in Patients With Chronic Heart Failure and Obstructive or Central Sleep Apnea

Evaluation Eines Leg Fluid Shift Und Erörterung Der hämodynamischen Und Respiratorischen Auswirkungen Auf Patienten Mit Chronischer Herzinsuffizienz Und Obstruktiver Oder Zentraler Schlafapnoe

This study aims to investigate the influence of a potential leg fluid shift (LFS) in patients with chronic heart failure (CHF) and obstructive sleep apnea (OSA) or central sleep apnea (CSA).

Chronic heart failure (CHF) is a common disease in general western population with high levels of morbidity and mortality. Prospective risk factors need to be identified and investigated. The prevalence for sleep disordered breathing (SDB) in patients with CHF is higher compared to general population. Especially the occurence of CSA with its special breathing pattern of Cheyne-Stokes-Respiration (CSR) is frequent in CHF patients.The pathophysiology and relation inbetween sleep apnea (SA) and CHF isn´t completely identified yet. Multiple theories with different strategies try to explain the pathophysics and development of SA. Following one of these theories, patients with CHF often develop edema in lower body compartments. The idea is a possible influence of retrograde nocturnal LFS from lower body to upper body compartments which could induce pulmonal congestion. Therefore, an increased pulmonary capillary wedge pressure (PCWP) could irritate special pulmonal receptors resulting in CSR with periods of hyperventilation, related hypocapnia and central apnea events. OSA could be induced by fluid accumulation in the upper airway by retrograde fluid shift. Patients with known CHF receive fluid measurements by b multi frequency bioimpedance analysis (mfBIA) the evening before and the morning after sleep is recorded using polygraphy (PG) or polysomnography (PSG) in hospital. Sleep results are analyzed by physicians using current guidelines of the American Academy of Sleep Medicine (AASM). Capillary blood gas (CBG) samples are taken before and after sleep to examine the relation of fluid shift and blood gas changes. A subgroup of the study group undergo additional investigation. Hemodynamic effects (e.g. reduced cardiac output (CO)) as a cause of a potential fluid shift is measured during wakefulness by using a tilting table. Hemodynamically relevant parameters are recorded non-invasively.

Patients receive Multi Frequency Bioimpedance Analysis (mfBIA) before and after sleep recording by Polysomnography/Polygraphy (PSG/PG) in hospital. Capillary Blood Gas Analysis (CBGA) is performed before and after sleep according to mfBIA.

Patients receive Multi Frequency Bioimpedance Analysis (mfBIA) before and after sleep recording by Polysomnography/Polygraphy (PSG/PG) in hospital. Capillary Blood Gas Analysis (CBGA) is performed before and after sleep according to mfBIA. Additionally, during daytime a special test with random parts of the study group basic is performed: A tilting table with hemodynamic monitoring is used to induce an artificial LFS by moving patients from vertical into horizontal position. Bodyfluid changes are monitored by mfBIA during this procedure.

Multi Frequency Bioimpedance Analysis (mfBIA) uses very small electric current at different frequencies (5, 50, 100 kHz) to measure the resistance and reactance of the entire body and different segmental body compartiments. With a special software total body fluid can be calculated. By analyzing raw data at different frequencies a detailed view on body and segments fluid distribution is possible.

Sleep is digital recorded by using PSG/PG in hospital and manually analyzed by physicians according to current AASM guidelines.

CBGA is a less invasive method to gain arterial blood like gas samples without the punctation of an artery. After inducing a good capillary perfusion, capillary blood is taken by a small punctation of the tip of one ear. The sample is automatically analysed in a blood gas analyzer.

A tilting table offers the opportunity to turn a study subject automatically from vertical into horizontal position and back. By using non-invasive monitoring technique, hemodynamic parameters are recorded permanently.

Inclusion Criteria: Chronic Heart Failure reduced left ventricular ejection fraction (LVEF) ≤ 45% NYHA I - IV Exclusion Criteria: current existing sleep apnoea breathing therapy significant chronic obstructive pulmonary disease (COPD) Tiffenau-Index: <70% respiratory insufficiency with need for a long time oxygen therapy hypercapnic state in rest at day time acute myocardial infarction at moment of study instable angina pectoris at moment of study cardiac surgery in last twelve weeks stroke or TIA in last twelve weeks implantable cardioverter-defibrillator, if there is no security clearance of the fabricator chronic kidney disease > Stage III