Clinical risk factors for prolonged PT/PTT in abdominal sepsis patients treated with moxalactam or tobramycin plus clindamycin

Factors associated with prolongation of the prothrombin time were analyzed by 94 patients with intra-abdominal sepsis. Patients were randomized prospectively to receive either the combination of tobramycin and clindamycin (TM/C) or moxalactam (MOX). This paper presents a retrospective review designed to compare the frequency of prolonged clotting times and to analyze predisposing factors. Prothrombin time (PT) prolongation occurred more frequently in patients given moxalactam (19 of 47 patients) than in patients given the combination of tobramycin and clindamycin (9 of 47 patients) (p < 0.05). Prolongation of the partial thromboplastin time (PTT) occurred in all patients with a prolonged PT. Liver disease, upper gastrointestinal surgery, and use of cimetidine were more frequent in those patients with abnormal PT/PTT values (p < 0.05). Two moxalactam-treated patients with subsequent PT/PTT prolongation had individual clotting factors assayed before moxalactam treatment and at the time of detection of the abnormal PT. The activity of clotting factors II, VII, VIII, IX, X, and XII was reduced during MOX therapy. Treatment with vitamin K reversed the abnormality. In view of underlying abnormalities and rapid response to parenteral vitamin K, the mechanism is probably an acute vitamin K deficiency superimposed upon chronic vitamin K deficiency. In patients with intra-abdominal infection, those treated with MOX are more likely to develop abnormal PT than those treated with TM/C. Since abnormal PT/PTT was common even in TM/C patients, supplemental vitamin K should be considered for all seriously ill, older patients with abdominal infections.