Fluid space measurements in burned children.

Fluid imbalance, caused by fluid loss and changes in capillary permeability, occurs during the acute phase of burns and scalds, and the extent of the loss has been shown to depend on the body weight and surface area damaged. The blister fluid may contain protein in a concentration up to 6 g./100 ml. and sodium up to 160 mEq/l., resembling lymph and interstitial fluid in the burned patient (Cope and Moore, 1944; Sevitt, 1957). There is a generalized increase in capillary permeability, resulting in a loss of protein from the plasma, principally of albumin (Cope and Moore, 1944; Cope, Graham, Moore and Ball, 1948; Bull, 1958), and a consequent fall in blood volume with movement of fluid into the interstitial space. Factors responsible for this change in permeability have been described by Miles and Wilhelm (1960) and Sevitt (1957). Fluid transfer ceases by the end of the second post-burn day, and Cope and Moore (1944) have shown that normal capillary permeability to radioactive dyes and proteins is restored within 40 hours after burn injury. Using thiocyanate ion and Na24, Cope and Moore (1947) found an increase in extracellular space in burned patients which was maximal in 36 to 48 hours. In contrast, Fogelman and Wilson (1955), in studies of scalded dogs and adult burned patients, found a decrease in extracellular space as measured by S3504, while the total body water remained unchanged. In support of this, the investigations of local thermal oedema by Rosenthal and Tabor (1945) in man, and by Fox and Baer (1947) in mice, indicate that sodium retention takes place in injured cells, resulting in a fall in plasma concentration accompanied by extracellular dehydration. In order to obtain more information into the distribution of fluid spaces in burned and scalded children experiments were performed to measure total body water and extracellular space, using antipyrine and sodium thiosulphate respectively. The total extracellular