Non-Invasive Hemodynamic Monitoring in a Collapsed Runner.

The mechanism of exercise-associated collapse (EAC) is multifactorial. Other diagnoses or serious causes of collapse must be excluded immediately. We report a 45-year-old male runner who collapsed during a half-marathon (21 km). The initial assessment showed he had hyperthermia, tachycardia, and hypotension. In the medical tent, we applied non-invasive hemodynamic monitoring, and the results showed his cardiac index was 3.9 L/min/m , total peripheral resistance index (TPRI) was 1,199 dynes × sec/cm /m (normal range: 1,970-2,390 dynes × sec/cm /m ), stroke volume variance was 8%. The runner had decreased vascular resistance, likely due to heat-related vasodilation, whereas adequate stroke volume variation indicated a relatively sufficient intravascular fluid status. This suggests the runner experienced exertional heat illness rather than a simple EAC. Initially, vigorous intravenous fluid resuscitation was given within the first 30 minutes. After the hemodynamic data indicated a relatively adequate fluid status, the rate of fluid administration was gradually reduced. External cooling methods were implemented which involving ice packing over the neck, axillae, and groin areas. His body temperature decreased. Tachycardia and hypotension were resolved. One hour later, the sequential hemodynamic monitoring showed an increasing TPRI (1,264 dynes × sec/cm /m ). In our case, the runner displayed peripheral vasodilation. The goal of treatment EAC is to restore adequate tissue perfusion through fluid resuscitation and restoration of vascular tone. Non-invasive hemodynamic serves as a valuable guide for a comprehensive treatment plan for collapsed runners in the field.