Observations on the activity of the renin-angiotensin-aldosterone (RAA) system after low volume colloid resuscitation for burn injury.

Studies of plasma renin activity (PRA) and plasma aldosterone in burn patients treated with a low volume colloid resuscitation regimen revealed very high levels of both hormones. Highest hormone levels occurred in the 5 days post burn with the correlation between PRA and plasma aldosterone r = +0.787 (p less than 0.001). The negative correlation between 24 hour urinary sodium excretion and PRA (r = +0.671, p less than 0.001), was closer than that between 24 hour sodium excretion and plasma aldosterone (r = -0.556, p less than 0.01). Secondary elevations of PRA and plasma aldosterone occurred in 2 patients (7-14 days after injury) associated with clinical deterioration and systemic sepsis.