IMPORTANCE OF POINT-OF-CARE ULTRASONOGRAPHY IN THE EVALUATION OF UNDIFFERENTIATED SHOCK

Abstract

SESSION TITLE: Fellows Critical Care Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Acute pulmonary embolism (PE) affects at least one in every 1000 individuals. Diagnosing PE accurately and in a timely manner can be challenging as the clinical presentation of PE is variable. In fact, up to two-thirds of clinically significant PE are undiagnosed until autopsy. Point-of-care ultrasonography (POCUS) has developed into a vital tool that can assist clinicians in appropriately diagnosing PE and elucidating etiology of undifferentiated shock. CASE PRESENTATION: A 71-year-old female with a history of reactive airway disease and minimal change nephropathy presented with two days of progressive dyspnea and wheezing. Vital signs on arrival were notable for tachycardia of 180 beats per minutes, hypotension of 86/50, and hypoxia which required four liters of supplemental oxygen to correct. Electrocardiogram showed new-onset atrial fibrillation (AF) with rapid ventricular response. Laboratory analysis was remarkable for a neutrophil predominant leukocytosis of 18.2 x 10^3/mcL, a serum bicarbonate of 14 mmol/L, blood urea nitrogen 36 mg/dL, creatinine 2.2 mg/dL, and a lactic acid greater than 12 mmol/L. A chest radiograph revealed no significant parenchymal infiltrates (Figure 1). Her condition quickly deteriorated requiring escalating doses of vasopressors and ventilatory support. POCUS cardiac exam identified right ventricular (RV) dilatation and McConnell’s sign (RV free wall hypokinesis with hyperdynamic apex) (Figure 2A-B). Furthermore, ultrasound evaluation of her lower extremities confirmed the presence of multiple deep vein thrombi. Given the high suspicion for massive PE, systemic intravenous tissue plasminogen activator was administered. Subsequently, hemodynamics started improving with a rapid decrease in vasopressor requirements. Unfortunately, the hospital course was complicated by acute renal failure prompting transition to comfort care measure per the patient’s wishes rather than pursing hemodialysis. DISCUSSION: Shock can be categorized into cardiogenic, hypovolemic, distributive/vasoplegic, and obstructive. Obstructive shock is caused by resistance to blood flow through the circulatory system. This can result from PE, cardiac tamponade, or pneumothorax. POCUS has been validated as a reliable tool to identify obstructive shock. Hallmark findings on POCUS for PE include, RV dilatation, septal flattening, paradoxical septal wall motion, and McConell’s sign. Additionally, the presence of new-onset AF in undifferentiated shock should prompt evaluation for PE, as those diagnosed with PE who present with AF have an increased mortality. CONCLUSIONS: Obstructive shock secondary to PE should always be considered in cases of undifferentiated shock. Moreover, all clinicians should become familiar with the role of POCUS in the evaluation of undifferentiated shock, as it can oftentimes provide rapid, reliable, and clinically actionable information. Reference #1: McLean A. S. (2016). Echocardiography in shock management. Critical care (London, England), 20, 275. https://doi.org/10.1186/s13054-016-1401-7 Reference #2: Walley, P. E., Walley, K. R., Goodgame, B., Punjabi, V., & Sirounis, D. (2014). A practical approach to goal-directed echocardiography in the critical care setting. Critical care (London, England), 18(6), 681. https://doi.org/10.1186/s13054-014-0681-z Reference #3: Matthews, J. C., & McLaughlin, V. (2008). Acute right ventricular failure in the setting of acute pulmonary embolism or chronic pulmonary hypertension: a detailed review of the pathophysiology, diagnosis, and management. Current cardiology reviews, 4(1), 49–59. https://doi.org/10.2174/157340308783565384 DISCLOSURES: No relevant relationships by Ethan Karle, source=Web Response No relevant relationships by Armin Krvavac, source=Web Response No relevant relationships by Tarang Patel, source=Web Response No relevant relationships by Rodger Wilhite, source=Web Response