“…A review of the literature on sleep quality and weaning outcomes from a mechanical ventilator showed that physiological, psychological and environmental factors impacted on sleep quality and might also affect the weaning outcomes. Physiologically, various studies have investigated the relationship between sleep quality and several relevant variables, including age (Reid et al 2006;Yao, Yu, Cheng, & Chen, 2008), gender (Machodo, Barreto, Passor, & Lima-Costa, 2006;Hsu and Li 2005), and long-term condition or number of existing chronic illnesses (Wu , Su , Fang, & Chang, 2012;Huang & Tsai, 2001). For instance , Foley, Ancoli-Israel, Patricia, & Walsh (2004) found that for 1,506 participants aged 55-84 years in the United States, more than 40% with four or more chronic illnesses rated their quality of sleep as fair or poor.…”