1. Department of Cardiothoracic Surgery, The Cangzhou Central Hospital, Hebei Province 061001, China
2. Department of Nursing, Cangzhou Medical College, Hebei Province 061001, China
3. Department of Medicine, Cangzhou Medical College, Hebei Province 061001, China
4. Department of Anesthesiology, Cangzhou Central Hospital, Hebei Province 061001, China