Ergonomic analysis of small-caliber trans-nasal gastroduodenoscopy and proposed solutions to ergonomic problems

Kazuhiko Shinohara, MD, PhD. Tokyo University of Technology

Background and Objective :Implementation of small-caliber trans-nasal gastroduodenoscopy (NGS) for the diagnosis of upper gastrointestinal disease has become widespread in Japan because it is associated with minimal discomfort. However, there has been some resistance to its implementation from physicians and nurses because its impact on workflow. We compared the workflow of physicians and nurses during NGS and conventional trans-oral gastroduonenoscopy (OGS) from an ergonomic standpoint.

Methods :The caliber of the NGS was 5.9 mm and that of the OGS was 10 mm. Endoscopic examination was performed under local anesthesia applied to the nasopharyngeal mucosa. The endoscope was inserted to the second portion of the duodenum, and the duodenum, stomach, esophagus and pharynx were closely observed. Both examinations were performed in 20 patients by the same physician, who has 30 years’ clinical experience. Workflow and ergonomic problems were investigated by process analysis methods from industrial engineering and by questionnaire.

Results :The number of preparatory processes was doubled for NGS. The additional processes affected the nurses and included administration of vasoconstrictors via nasal cannula and local anesthesia via vaporizer. The number of processes for examination by NGS were the same as for OGS, but the mean examination times without biopsy maneuvers were much longer for NGS at 234.0 s (SD = 118, n = 20) than for OGS at 120.1 s (SD = 31.6, n = 20). These differences resulted from decreased suction and insufflation compared with OGS. Additional ergonomic problems associated with NGS that affected the physicians included spatial orientation of the nasal and upper pharyngeal cavities, impaired maneuverability of the small-caliber shaft, and poor maneuverability of the NGS biopsy forceps due to their small caliber.

Discussion : We found that NGS entailed additional preparatory work of the nasal cavity and caused maneuverability problems with its small-caliber endoscope and accessory devices. For smooth and safe implementation of NGS to examine for gastrointestinal disease, the ergonomic problems can be resolved by developing a packaged preparation kit, providing appropriate training through simulation, augmenting power for suction and insufflation, and providing adequate holding devices, accessory devices, and gloves for the small-caliber endoscope. Further analysis of the workflow of the medical staff involved is required.

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