Proceedings of The Physiological Society

Physiology 2016 (Dublin, Ireland) (2016) Proc Physiol Soc 37, PCA106

Poster Communications

Teaching acid-base homeostasis using human patient simulation

J. R. Harris1, F. M. MacMillan1, E. Lloyd1, R. J. Helyer1

1. School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.


Understanding acid-base homeostasis is important for students of biomedical sciences as well as those studying medicine, dentistry and veterinary science. However, it is acknowledged that undergraduate students find acid-base physiology a conceptually difficult topic [1]. We have previously described the use of a human patient simulator (HPS) in enriching (alongside lectures and practical classes) physiology curricula for biomedical undergraduates, especially in cardiovascular [3] and respiratory [4] physiology teaching. Here we show this method extended to demonstrating key aspects of acid-base physiology. Our aim was to produce a set of simulated patients that accurately model acid-base disturbances (acute and chronic respiratory acidosis; metabolic acidosis and metabolic alkalosis) using the CAE HPS (CAE Inc, Canada). The HPS has an adjustable physiologic model that allows construction of simulated patients with pathophysiological profiles based on clinical studies and real patient data. Vital signs (such as pulse and state of consciousness) are displayed on a manikin, whilst real-time numerical data from physiological variables are displayed either on a simulated clinical monitor or as a table of values changing in real-time. In our acid-base session students are presented with a range of data but focus on changes in respiratory rate, tidal volume, arterial carbon dioxide and pH during the simulation of each disturbance. An overview of considerations in designing patients is provided elsewhere [2]. During the session, students (around 25 per group) make physical observations on the HPS manikin as well as recording numerical data. Each of the four acid-base disturbances is then mapped, using student worksheets, onto an acid-base nomogram. This enables variables that are not displayed on the clinical monitor (e.g. arterial bicarbonate) to be deduced. The mapping task also facilitates discussion of the potential causes of acid-base disturbances and of their underlying (patho)physiology, thereby enhancing and reinforcing lecture-based learning. Questions (multiple choice and data handling) derived from data produced during the session can be used in examinations. Feedback for the session is very good, with second year medical student questionnaires typically recording around 90% of responses as ‘Excellent' or ‘Good'. We initially developed the acid-base simulation teaching session for undergraduate medical students with the aim of demonstrating core principles of basic physiology in a patient-led manner that would spark their interest and lay the foundation for greater understanding later in practice. We have since adapted the session to create a data-handling based, plenary session for veterinary students. In future we also plan to embed the session in biomedical science teaching for undergraduate students of physiology and related disciplines.

Where applicable, experiments conform with Society ethical requirements