Apnea (Central and Obstructive) Clinical Trial
Official title:
The First Affiliated Hospital of Nanjing Medical University
Fluid retention in the legs due to chronic heart failure (CHF) during the daytime may redistribute to neck when with supine positioning at night. A portion of the shifted fluid accumulates in the neck, and narrows the upper airway, predisposing the patient to obstructive sleep apnea (OSA) and central sleep apnea (CSA). However, the mechanism of overnight fluid shift on OSA and CSA remains unclear. The investigators pre-experiment demonstrated there may be a different mechanism of overnight fluid shift on OSA and CSA. The accumulation of water content in neck soft tissue increases neck circumference and leads to pharyngeal resistance, upper airway collapse and causes OSA. The effect of nocturnal fluid shift on CSA may be because of increasing of chemosensitivity (fluctuation of PaCO2), circulation delay and hemodynamic disordered. This study is aimed to explore the different mechanism of overnight fluid shift on OSA and CSA by comparing the changes of upper airway (inside diameter, water content, and pharyngeal resistance), PaCO2, circulation delay (lung-to-finger circulation time) and hemodynamic (loop gain).
Methods:
Between June 2015 and December 2017, 180 patients with chronic heart failure caused by
rheumatic heart disease, cardiomyopathy and coronary heart disease (in Cardiology Department
and Cardiothoracic Surgery Department of the First Affiliated Hospital of Nanjing Medical
University), were screened for sleep apnea by polysomnography (PSG). Of them, 20 obstructive
sleep apnea (OSA) and 20 central sleep apnea (CSA) were enrolled. Clinical evaluations
including NYHA class, electrocardiographic, echocardiographic, arterial blood gas analysis
findings, baseline medication, and 6-minute walk test (6MWT) were recorded.
The fluid index, head and neck CT and pharyngeal resistance were tested at 20:00. Then a full
night PSG and percutaneous PaCO2 were performed. The fluid index, head and neck CT and
pharyngeal resistance were repeated at 6:00 after PSG.
The volume of fluid shift from legs to head and neck,inside diameter of the upper airway, and
water content of neck soft tissue were calculated. The lung-to-finger circulation time and
loop gain were measured.
1. Mechanism of overnight fluid shift on OSA:
Fluid shift volume from legs to head and neck,inside diameter of upper airway, water
content of neck soft tissue, percutaneous PaCO2, severity of sleep apnea, minimum SP02,
lung-to-finger calculation time and loop gain were measured at 22:00 and repeated at
6:00 next morning in patients with OSA.Correlations between changes of fluid shift
volume and changes in diameter of upper airway, water content of neck soft tissue,
PaCO2, minimum SP02, lung-to-finger calculation time and loop gain were analyzed.
2. Mechanism of overnight fluid shift on CSA:
Fluid shift volume from legs to head and neck,inside diameter of upper airway, water content
of neck soft tissue, percutaneous PaCO2, severity of sleep apnea, minimum SP02,
lung-to-finger calculation time and loop gain were measured at 22:00 and repeated at 6:00
next morning in patients with CSA.Correlations between changes of fluid shift volume and
changes in diameter of upper airway, water content of neck soft tissue, PaCO2, minimum SP02,
lung-to-finger calculation time and loop gain were analyzed.
;