Critically burnt patients: Haemodynamic status, oxygen transport and consumption, plasma cytokines

Objective: To assess the haemodynamic and oxymetric variations measured by a pulmonary artery catheter and to correlate them with the variations of the circulating cytokines during the initial intensive care phase of severely burned patients. Study design: Prospective study covering an 18-month period. Patients: Thirteen successive patients, aged over 12 years, without significant medical history, with a thermal burn affecting more than 50 percent of their total body surface area and admitted to our centre during the first six postburn hours. Methods: The haemodynamic and oxymetric profile was investigated by inserting a blood flow-directed balloon-tipped pulmonary artery fiberoptical catheter. All patients were treated according to the protocol previously used in our centre. Blood samples were drawn on admission, every 12 hours post-injury until the 2nd day, then on the 3rd and 5th days. Cytokines were analyzed by Elisa method. Haemodynamic and oxymetric measurements were achieved simultaneously with the biological samples during the first 5 postburn days. The analysis of variance (ANOVA) with the Duncan test was utilized for multiple comparisons between continuous variables. Results ((x) over bar +/- SEM): The patients were 32 +/- 3 years-old and had a burn surface of 72 +/- 4%. After a short hypovolemic shock period lasting a 12 hours, a hyperdynamic shock occured which increased until the 5th day, with an increased cardiac index (6.9 +/- 0.4 at h120 vs 2.9 +/- 0.3 L . min(-1). m(-2) at h6, P < 0.05), increased oxygen transport and consumption (respectively 880 +/- 77 at h72 vs 543 +/- 58 mL . min(-1) at h12, P < 0.05 and, 203 +/- 5 at h72 vs 129 +/- 25 mL . min(-1) at h6, P < 0.05) and markedly decreased systemic vascular resistances (1,002 +/- 118 at h36 vs 2,330 +/- 328 dyn . s . cm(-5). m(2) at h6, P < 0.05). Circulating cytokines were not clearly modified except for interleukine-6 which reached early striking peaks (16,858 +/- 10,330 at h24 and 15,406 +/- 6,509 pg . mL(-1) at h36) simultaneously with the decrease in systemic vascular resistances. Conclusions: During the first post-injury week, critically burned patients develop a specific hyperdynamic circulatory status during which interleukine-6 could be a mainfactor decreasing systemic arterial resistances.