Principles of Hypotensive Shock: A Video Introduction to Pathophysiology and Treatment Strategies

AUDIENCE: Emergency medicine interns, medical students, and mid-level providers (physician assistants, nurse practitioners). INTRODUCTION: Shock is defined as a state of global tissue hypoxia and is typically the result of hypotension and circulatory system failure. A variety of disease states may ultimately culminate in hypotensive shock through one or more generally recognized mechanisms – hypovolemic, cardiogenic, obstructive, and/or distributive shock.1 These mechanisms differ significantly in terms of their pathophysiology and requisite treatment. While the effects of hypotensive shock are initially reversible, untreated hypotensive shock may rapidly progress to multiorgan failure and death. Hence, the ability to promptly recognize a state of hypotensive shock, identify the underlying mechanism, and administer appropriate therapies are skills required of those caring for critically ill patients.2 The evaluation of hypotensive shock in the Emergency Department is relatively commonplace. Mortality rates associated with shock are high, ranging from 22.6% – 56.2%, depending upon the underlying etiology.3 For these reasons, the authors believe that a web-based learning module addressing topics related to hypotensive shock would be beneficial to healthcare professionals who are likely to encounter it in clinical practice. The web-based nature of the module would lend itself to convenient viewing and would allow for utilization as a just-in-time training modality. Presenting these topics in an animated format may also be a useful way of displaying the complex nature of cardiovascular physiology. EDUCATIONAL OBJECTIVES: By the end of this module, participants should be able to: 1. Review basic principles of cardiovascular physiology. 2. Describe the four general pathophysiologic mechanisms of hypotensive shock. 3. Recognize various etiologies for each mechanism of hypotensive shock. 4. Recognize differences in the clinical presentation of each mechanism of hypotensive shock. 5. Cite the basic approach to treatment for each mechanism of hypotensive shock. EDUCATIONAL METHODS: This is a video podcast which conveys information through animated content. It is available to learners on demand and just-in-time for practice. It may be used as a stand-alone educational tool, as a primer to other instructional methods (eg, simulation, flipped classroom setting, or case discussions), or a just-in-time training tool. RESEARCH METHODS: A small-scale study was performed to quantify the efficacy of this module as an educational tool. The learner group was comprised of a convenience sample of third-year medical students in the midst of their core clinical clerkships. All third-year students were eligible to participate, regardless of which core clerkship they were currently engaged in. Third-year students were contacted via email regarding participation. Participation was completely optional – no incentive was offered, and students were informed that participation would not in any way affect their clerkship grades. For these reasons, an Instructional Review Board review was not necessary. Ten third-year medical students volunteered to participate. In the course of a single, hour-long session, learners were administered the attached assessment form as a pre-test, shown the video module, and then asked to immediately retake the assessment as a post-test to assess for improvement. Assessments were graded on a 17-point scale, according to the attached answer key. Learners were also given the opportunity to provide subjective feedback on the quality of the module as an educational tool. RESULTS: For this assessment, the maximum possible score was 17 points. The average pre-test score across all learners was 11.75 (69.12%) with a standard deviation of 3.24. The average post-test score across all learners was 15.12 (88.97%) with a standard deviation of 3.31. All learners demonstrated improvement in scores on the post-test, with a maximum and minimum improvement of 6 points and 1 point respectively. On average, learners improved by 3.38 points (p = 0.029, 95% confidence interval, 1.97 to 4.78). Statistical significance was established using a paired student’s T-test. All learners agreed with the statement, “This module effectively taught concepts related to hypotensive shock.” Learners were also given the opportunity to provide subjective feedback regarding the module and responded with statements like, “comprehensive review of the subject,” and “very helpful review for clinical clerkships.” DISCUSSION: Data from learner assessments suggest that this module is effective in communicating concepts related to hypotensive shock. Learner satisfaction with the module was unanimous. These results suggest that this module would be effective as a standalone educational tool, or as a primer to other instructional methods. Areas of further investigation may include assessment of a larger learner population, assessment of learners at additional stages of clinical training, and assessment of long-term knowledge retention. TOPICS: Shock, hypotension, cardiovascular physiology, pulmonary artery catheterization, flipped classroom, asynchronous learning, emergency medicine.