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Background: Deglutition studies are fluoroscopic procedures that utilize swallowed barium with concurrent x-ray imaging to diagnose swallowing disorders. The x-ray images during these studies can occur at variable pulses per second (p/s) depending on the institution and its available fluoroscopy equipment. At many institutions, radiologist preference is the main factor in determining which of the p/s settings is used.
Significance of the Problem: Increasing the p/s setting increases the patient's exposure to ionizing radiation, and the risks of radiation exposure have been well-established in literature for both children and adults. Exposure to radiation has been linked to increased rates of leukemia and a wide array of solid organ cancers. Compared to adults, children are more sensitive to radiation and ten times more likely to develop these radiation-induced cancers. Exposure to ionizing radiation during diagnostic imaging has demonstrated a small but significant increase in cancer development in children. While undergoing a deglutition study at a higher p/s setting increases the patient's exposure to radiation, it is possible that a higher p/s setting may be more sensitive at detecting swallowing disorders since additional imaging frames are collected and analyzed. Increasing p/s setting may also lead to a more accurate diagnosis with a more fitting treatment plan.
Hypothesis: If the higher p/s setting has a significantly higher rate of aspiration compared to the lower p/s setting, then we can conclude the higher p/s setting is more sensitive for detecting aspiration. On the contrary, if no difference is found in the aspiration rate between different p/s groups, then this study will help limit unnecessary radiation exposure by recommending lower p/s settings for future deglutition studies.
Methods: We conducted a large-scale, retrospective study where we collected data from each deglutition study performed at Children's Hospital & Medical Center over a two-year period that met specific criteria. A separate data point was included for each consistency tested within each deglutition study. For each consistency tested, we tracked whether aspiration was present and the p/s setting used for that consistency. Chi-square tests of independence were performed to examine the relationship between the rate of aspiration and the two p/s settings for each of the five consistencies: thins, thin nectar, thick nectar, honey, and puree. We utilized an alpha level of .05 for significance.
Results: Aspiration rate was not significantly impacted by whether the 3 or 7.5 p/s settings was used when the type of swallowed consistency (thins, thin nectar, thick nectar, honey, and puree) was controlled for chi-square. In other words, p/s setting and rate of aspiration were found to be independent of one another.
Conclusions: Our results suggest that aspiration rate was not significantly different between the 3 and 7.5 p/s settings when the type of swallowed consistency was controlled for. Therefore, we can conclude that the rate of aspiration detection does not increase with use of the higher 7.5 p/s setting.
Because our data concludes that the higher 7.5 p/s setting does not increase aspiration detection, we recommend utilizing the lower 3 p/s setting for future deglutition studies to minimize unnecessary radiation exposure.
Wong, Lincoln, "Do Additional Pulses per Second in Pediatric Deglutition Studies Increase the Rate of Aspiration Detection?" (2023). Child Health Research Institute Pediatric Research Forum. 69.