Acquired Antithrombin III (AT III) - Deficiency in Septicaemia

AT III was measured in 34 patients with clinical and bacteriological evidence of septicaemia using a heparin cofactor assay. Based on the results of positive blood cultures gram-negative septicaemia (G^-S) was diagnosed in 10 (group 1) and gram positive septicaemia (G+S) in 9 patients (group 2). From the remaining 15 patients {group 3) blood cultures before onset of antibiotic therapy were not obtained and gave negative results throughout the observation period. Based on bacteria] cultures from other sites than venous blood or bacteriological examination of spinal fluid G^-S was assumed in 13 and G⁺S in 2 patients.

In all but one patient of group 1 and one of group 2 AT III activities were decreased below 2 SO of normal controls (n = 91, x = 99.6, SD-8.4) already at the time of the first coagulation screening (patients: n=34, =58.4, SD-16.6). Analysis of var-ance showed no significant difference between the mean values of the three groups at the c per cent (%) level. The minimal AT III activities during the course of the disease were below the norma] range in all patients studied [n=34, =51.2, SD=13.6).

Thus AT III deficiency appears to be a constant and early finding in G^-S and G⁺S, causing insufficient inhibition of blood coagulation, and hereby may contribute to irreversible tissue damage caused by microthrombi in septic shock. This deficiency may be an important factor in the failure of heparin therapy to reduce mortality from septic shock.