Chronic inflammatory response in the rat lung to commonly used contrast agents for videofluoroscopy

Risk Factors for Aspiration Pneumonia After Receiving Liquid-Thickening Recommendations

Objective

We examined the influence of liquid thickness levels on the frequency of liquid penetration-aspiration in patients with dysphagia and evaluated the clinical risk factors for penetration-aspiration and aspiration pneumonia development.

Study Design

A case series.

Setting

Single-institution academic center.

Methods

We reviewed medical charts from 2018 to 2019. First, we evaluated whether liquid thickness levels influence the frequency of liquid penetration-aspiration in patients with dysphagia. Penetration-aspiration occurrence in a videofluoroscopic swallowing study was defined as Penetration-Aspiration Scale (PAS) scores ≥3. Second, the association between liquid thickness level and penetration-aspiration was analyzed, and clinical risk factors were identified. Moreover, clinical risk factors for aspiration pneumonia development within 6 months were investigated.

Results

Of 483 patients, 159 showed penetration-aspiration. The thickening of liquids significantly decreased the incidence of penetration-aspiration (P < .001). Clinical risk factors for penetration-aspiration were vocal fold paralysis (odds ratio [OR], 1.99), impaired laryngeal sensation (OR, 5.01), and a history of pneumonia (OR, 2.90). Twenty-three patients developed aspiration pneumonia while undertaking advised dietary changes, including liquid thickening. Significant risk factors for aspiration pneumonia development were poor performance status (OR, 1.85), PAS score ≥3 (OR, 4.03), and a history of aspiration pneumonia (OR, 7.00).

Conclusion

Thickening of liquids can reduce the incidence of penetration-aspiration. Vocal fold paralysis, impaired laryngeal sensation, and history of aspiration pneumonia are significant risk factors of penetration-aspiration. Poor performance status, PAS score ≥3, and history of aspiration pneumonia are significantly associated with aspiration pneumonia development following recommendations on thickening liquids.

Level of Evidence

3.

The effects of barium concentration levels on the pulmonary inflammatory response in a rat model of aspiration

PURPOSE

Barium sulfate (Ba) suspension is the most widely used contrast agent for upper gastrointestinal and videofluoroscopic swallow studies (VFSS). The effect of Ba concentration on lung injury is uncertain. The aims of this study were to explore the effects of different barium concentrations on the respiratory organs and elucidate the underlying mechanisms of these effects in an established animal model of aspiration.

METHODS

Animal model study. Eight-week-old male Sprague-Dawley rats were allocated into three groups (n = 12, each group). Two groups underwent tracheal instillation of low (30% w/v) and high (60% w/v) concentration Ba (low-Ba, high-Ba). A control group was instilled with saline. Half of the animals were euthanized on day 2 and the remaining half were euthanized on day 30. Histological and gene analyses were performed.

RESULTS

Both low-Ba and high-Ba aspiration caused inflammatory cell infiltration in the lung at 2 days post aspiration with an increase in the expression of inflammatory cytokines. At 30 days post aspiration, small quantities of barium particles remained in the lung of the low-Ba group without any inflammatory reaction. Chronic inflammation was recognized in the high-Ba group up to 30 days post aspiration.

CONCLUSION

A small amount of high concentration Ba (60% w/v) caused sustained inflammation in the rat lung at least 30 days after aspiration. Even with a small amount of low concentration Ba aspiration (30% w/v), Ba particles can remain in the lung over a month, causing sustained late effects.