Respiratory complications
Pneumonia is one of the most common infections following cardiac surgeries with a cohort study reporting its cumulative incidence as 2.4% [40]. The prolonged use of NG tubes has been widely reported to be associated with an increased incidence of pneumonia [40,41]. The reported prevalence of pneumonia following NGT use was shown to vary ranging from 4 to 95% with associated mortality rates of 17-62% [38,40,42]. One study reported that NG tube use was the strongest risk factor for developing nosocomial pneumonia indicated by having the highest odds ratio (6.48, 95% confidence intervals = 2.11 to 19.82) in a sample of 203 patients [43]. NG tubes affect the proper functioning of the gastroesophageal sphincter which then leaves patients more susceptible to maxillary sinusitis, oropharyngeal colonization, and bacterial migration providing a possible explanation of the strong association found between NG tube use and pneumonia occurrences following cardiac surgery [41]. Furthermore, it is postulated that the presence of the NGT can promote aspiration leading to aspiration pneumonia. The mechanism by which aspiration may be promoted includes the loss of anatomical integrity of the esophageal sphincters, increased frequency of lower esophageal sphincter relaxation, and the desensitization of the pharyngoglottal adduction reflex [38].