Identifying esophageal motility disorders prior to surgical intervention is imperative when determining the procedural route that will produce the greatest positive patient outcome and reduce postoperative sequelae related to preoperative conditions. Possible disparities have been identified between HRM and UGIMM assessment results. Identifying testing variables and standards that could impact the obtained results will allow providers the ability to create a more customized plan of care and increase outcome predictability. Therefore, examining HRM and UGIMM level of agreement is essential to providing the best evidence-based practice care and meeting the unique needs of individual patients.
Currently, HRM results are noted as the standard benchmark for adequate assessment of esophageal motility function and disorders. Esophageal manometry testing provides a means to determine if the esophagus is functioning properly through a series of wet swallows. As a patient swallows, the esophagus contracts in an orderly sequence to push the swallowed contents into the stomach. Once the contents enter the stomach, the Lower Esophageal Sphincter (LES) closes to prevent backflow, or reflux, of stomach contents into the esophagus. Any impairment to esophageal motility can compromise clearance and sphincter function, leading to adverse outcomes such as the development of intestinal metaplasia due to prolonged exposure of the mucosa to gastric acid. Assessment of motility and sphincter function is vital prior to any surgical intervention that involves manipulation of the gastroesophageal junction (GEJ) or surrounding structures. Inaccurate surgical manipulation can cause undesired pressure changes and alterations in normal peristalsis within the esophageal body.
By assessing preoperative baseline esophageal function, postoperative changes can be better predicted and adequacy of surgical intervention assessed. Some studies have noted that HRM metrics can predict overall surgical response and postoperative outcomes. Identification of motility dysfunction, or an incompetent LES, can be obtained during this examination, even in asymptomatic patients.
During HRM testing a flexible, small-bore probe will be passed via the nasal passages, down the esophagus and into the stomach. The patient is then asked to swallow a 5-milliliter saline fluid bolus while in the supine position for an average of 10 swallows. The test is then repeated in the standing, or upright, position for comparison. Pressure sensors on the probe record esophageal pressure, motility configurations, and contraction patterns. During the examination data is transmitted, via the probe, to a software program with the capability to autogenerate an analysis and diagnosis of the data. However, the autogenerated analysis can be situationally limited, therefore, the test administrator must possess a high level of understanding and keen interpretation skills to produce a completely accurate diagnosis. During study analysis it is often necessary to adjust anatomical markers, such as the location of the LES, Upper Esophageal Sphincter (UES), and the diaphragm, as the preset software data is unable to compensate for certain situational factors that may impact marker placement, such as GEJ morphology. The test administrator will identify and mark the UES, LES, and the pressure inversion point (PIP) during the interpretation phase. The integrated relaxation pressure (IRP) is then autocalculated, and provides a measurement of deglutitive relaxation during a 10 second time frame after the swallow is completed. The distal contractile integral (DCI) is also auto calculated and measures dynamism of peristalsis within the muscles of the esophagus. The PIP allows for evaluation of transition from the intra-abdominal cavity to the intrathoracic cavity. HRM results are categorized using the standardized Chicago Classification system which is subdivided into 4 hierarchical categories: 1) incomplete LES relaxation, 2) major motility disorders, 3) minor motility disorders, and 4) normal esophageal motility. Given that the test administrator has the ability to manipulate measurement markers during the analysis process, the need exists to identify possible gaps in consistency among test administrators, examine expected HRM results against other testing measures, such as the UGI MM test, and determine the impact the results have on patient outcomes.
A less invasive alternative to the HRM test is the UGIMM study. The UGIMM study is conducted under fluoroscopy and allows for the evaluation of motility function in real time, as well as visualization of anatomical structures. During the procedure radiographs are taken while the patient swallows a self-defined sip of barium in the standing position. The patient is then placed in the Trendelenburg position and asked to swallow a barium-soaked marshmallow while another set of radiographic images are taken. Each marshmallow measures the same, weighing approximately 6 grams. The UGIMM study currently does not have an established classification system by which result measurements are validated. However, exam outcomes are generally measured as follows: normal if the bolus clears the esophagus within 2 swallows or less; borderline swallowing dysfunction if the bolus clears within 3-4 swallows; abnormal swallowing function if 5 or more swallows are required to clear, or if a portion of the bolus remains after 5 swallows.
