Impact of Pulse Rate on Swallowing Impairment Assessment and Radiation Exposure

Modified Barium Swallow Studies (MBSSs) are the key diagnostic test to identify abnormalities in the structures and functions of swallowing. MBSSs are also used to test diet modifications, compensatory strategies and exercises to support clinicians’ treatment decisions for patients with dysphagia. However, MBSSs are a type of fluoroscopic study that uses ionizing radiation. Radiation exposure from medical tests are mandated to be as low as reasonable achievable. Pulse rate is a MBSS setting that is a main target for reducing radiation exposure. Unfortunately, decreasing pulse rate also decreases the information available from which to judge swallowing impairment. Since the oropharyngeal swallow only lasts approximately 1 second, when pulse rate is decreased from 30 to 15, the number of unique images available to judge swallowing impairment also decreases from 30 to 15. The effect of this reduction of information could threaten the accuracy of our judgments of swallowing impairment and lead to the use of incorrect rehabilitation strategies. The consequences of incorrectly assessing swallowing impairment are serious. If swallowing impairment exists and is un- or under- detected, airway protection and nutrition may be at risk. Inaccurate judgments may also err on the side of overly conservative recommendations of oral intake restriction such as modifications in diet or tube feeding placement and which would unnecessarily decrease a dysphagic patient’s health status and quality of life. Furthermore, it is not even clear that decreasing pulse rate is a meaningful decision with respect to reducing cancer risk as we do not know the levels of radiation exposure and cancer risks associated with MBSSs. Knowledge of the effect of reducing pulse rate on judgments of swallowing impairment and radiation exposure is important to the ability to weigh the risk of erroneous judgments of swallowing impairment against the benefit of the radiation reduction and make informed decisions about pulse rate setting. Thus, the goal of this study is to quantify the effect of reducing pulse rate on judgments of swallowing impairment and radiation exposure. Toward this goal, the specific aims of this proposal are: Aim 1. Quantify the impact of pulse rate on swallowing impairment severity assessment and treatment recommendations. Aim 2. Quantify radiation dose during MBSSs. Aim 3. Quantify the cancer risk based on radiation dose. The results of this study will provide the information needed to weight the risks and benefits of the different pulse rates used in MBSSs. This evidence will serve as a guide for speech-language pathologists, radiologists and hospital safety boards when evaluating MBSSs procedures and inform patient management decisions.