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].