HEMODYNAMIC-STUDY OF SEVERE BURN PATIENTS DURING THE 1ST 72 HOURS

The haemodynamic time course of 16 patients with severe burn injury was investigated using a flow-directed balloon-tiped pulmonary artery catheter. The patients, aged 33.8 +/- 5.5 years, were burnt over 60 +/- 10 %, of body surface area, with a UBS score of 228 +/- 43. The measurements were obtained every six hours after insertion of the catheter. Fluid load was determined with Evans' formula, and modified according to the haemodynamic data. Catecholamines were introduced when this and a trial of fluid loading with 5 ml . kg-1 of macromolecules during a 20 min period had failed, starting with dobutamine or dopamine, followed by adrenaline as required. During the first hours after the injury, circulatory shock was partly linked to hypovolemia : mean arterial pressure was 60.1 +/- 7.8 mmHg, right auricular pressure 4.5 +/- 2 mmHg, pulmonary wedge pressure 4.7 +/- 2 mmHg, cardiac index 3.5 +/- 0.8 l . min-1 . m-2. However, during the second and third days, cardiac output increased, with a cardiac index at 4.7 +/- 0.6 l . min-1 . m-2 and 5.2 +/- 0.2 l . min-1 . m-2 respectively. and arterial vascular resistances were decreased (536 +/- 125 dyn . s . cm-5). These data suggest a specific haemodynamic profile in severe burn patients which justifies invasive monitoring, and the use of catecholamines, in those patients that do not respond to fluid loading. The link between these data and the concomitant metabolic disturbances due to the burn injury has not yet been established. The increase in cardiac index could be related to the inflammatory response. Further studies are necessary to assess the choice and usefulness of catecholamines in the treatment of severe burn patients, as well as the benefit of thus increasing the cardiac index in order to improve tissus oxygen delivery.