Circulating blood volume in burn resuscitation

Circulating blood volume (CBV) was prospectively measured in patients with almost solely smoke inhalation injury (Group I: 10 patients) and in patients with severe cutaneous burn (Group B: 6 patients) consecutively until 96 hours after injury, to assess the effect of either injury on intravascular volume status by the pulse dye-densitometry method. All participants were treated by an ordinary fluid regimen based on the Parkland formula with an hourly urine output of 1.0 to 2.0 ml/kg for the resuscitation endpoint. CBV was also measured in 15 elective surgical patients for a control value (76.7+/-9.0 ml/kg). The level of CBV values in Group I was low, ranging from 54.4+/-6.9 ml/kg to 59.6+/-6.2 ml/kg (from 70.9% to 77.7% of control value), while in Group B from 48.5+/-5.5 ml/kg to 55.6+/-17.3 ml/kg (from 63.2% to 72.5%) until 72 hours after injury. There was no significant difference in CBV values between the two groups throughout the study period. We could elucidate the existence and extent of intravascular volume depletion in spite of optimal fluid treatment in both solely smoke inhalation injury and solely severe cutaneous burn. Almost solely inhalation injury was found to decrease CBV to less than that of severe cutaneous burn, which presumably led to the increased fluid requirement. Concerning the resuscitation endpoint in early burn treatment, this depletion in CBV must be taken in mind. Hourly urine output is speculated to be an effective and practical clue to manage a burn patient within permissive hypovolemia.