Acute cardiovascular effects of firefighting and active cooling during rehabilitation

Abstract

Objectives: To determine the cardiovascular and hemostatic effects of fire suppression and postexposure active cooling.

Methods: Forty-four firefighters were evaluated before and after a 12-minute live-fire drill. Next, 50 firefighters performing the same drill were randomized to undergo postfire forearm immersion in 10 °C water or standard rehabilitation.

Results: In the first study, heart rate and core body temperature increased and serum C-reactive protein decreased but there were no significant changes in fibrinogen, sE-selectin, or sL-selectin. The second study demonstrated an increase in blood coagulability, leukocyte count, factors VIII and X, cortisol, and glucose, and a decrease in plasminogen and sP-selectin. Active cooling reduced mean core temperature, heart rate, and leukocyte count.

Conclusions: Live-fire exposure increased core temperature, heart rate, coagulability, and leukocyte count; all except coagulability were reduced by active cooling.

Figure 1

Typical graph of body temperature over elapsed time before, during and after fire suppression, study 1.

Figure 2

Effect of active cooling in study 2 on: a) median core temperature 0–15 minutes post-fire, b) median core temperature 0–50 minutes post-fire, c) median heart rate 0–15 minutes post-fire, and d) median heart rate 0–50 minutes post-fire. Solid lines are controls (thin solid lines are 95% CI) and dashed lines are active cooling (thin dashed lines are 95% CI).