Swallowing study using water-soluble contrast agents may increase aspiration sensitivity and antedate oral feeding without respiratory and drug complications: A STROBE-compliant prospective, observational, case-control trial

Although the modified barium swallowing study (MBSS) is considered the gold standard for assessing aspiration risk, aspiration of lipid-soluble barium can cause chemical pneumonitis or impair radiologic interpretation of the lungs. Water-soluble contrast agents (WSCAs) may avoid these complications while maintaining sensitivity on aspiration. This prospective, observational, case-control cohort trial evaluated all patients >3 years old referred for swallowing study from September 2015 to November 2017. Repeat evaluations of individuals were excluded. High-risk patients were evaluated by WSCA (iohexol)-based swallowing study (WSS) and others by MBSS. The study included 829 evaluations of 762 patients. After excluding 74 evaluations, 365 WSSs and 390 MBSSs were performed. The most frequent underlying condition was brain lesion, followed by aspiration pneumonia. Aspiration occurred more frequently in WSS (147 patients: 40.3%) than in MBSS (36 patients: 9.2%) (P = .00). However, neither aspiration volume (6.72 cc [3.09-10.35] vs 5.53 cc [2.21-8.85]) nor radiographic alterations differed between the 2 groups (P > .05). Moreover, the swallowed (16.62 cc [8.45-24.79]) and aspirated amounts of iohexol were not correlated with radiologic changes or deterioration (P > .05). Switching to oral feeding following WSS was more frequent (164 patients: 44.9%), whereas aspiration pneumonia was not (P = .00). WSS did not prolong the interval to patient discharge (P = .06) or induce an allergic reaction or chemotoxicity over 1 week. The absence of aspiration-induced complications and adverse drug effects suggests that, compared with MBSS, WSS may increase aspiration sensitivity and early switching to oral feeding.