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Total parenteral nutrition (TPN) today is a fundamental procedure in the treatment of critically ill patients, especially if they have serious gastrointestinal diseases. However, use of the central venous catheter is connected with a very important morbidity. At the "Istituto di Patologia Chirurgica" and at the "Intensive Care Unit" of the University of Ferrara, we analyzed 59 cases of deaths from different diseases, on whom a postmortem examination had been performed. Twenty-seven patients had had no central venous catheter: none of them presented thrombosis of the central veins. Thirty-two patients had had a central venous catheter for TPN: five of them presented thrombosis of the central veins at the post-mortem examination. Except for one case who had thrombosis connected with a carcinoma of the right main bronchus, four cases (12.9%) presented thrombosis due to the central venous catheter. The subclavian vein seems to be more commonly connected with thrombosis than the jugular vein.

To evaluate plasma dopamine concentration and the effects of low doses infusion on urinary output after abdominal vascular surgery in patients with renal function impairment we performed a prospective clinical study. Twenty hemodynamically stable patients (mean age 66.6 years), with serum creatinine concentration2 mg %, who undergoing general anesthesia for major vascular surgery participated. A low dose of dopamine (3 micrograms/kg/min) was administrated to patients with postoperative protracted urinary output0.5 ml/kg/hr for at least eight hours. Plasmatic determinations were taken at T0 (no dopamine administration), when urinary output began to increase, or if not, after two hours (T1), at eight (T2), and 24 (T3) hours after the beginning of infusion. After 24 hours the dopamine infusion was stopped and the patient's plasmatic level was measured four hours later (T4). Dopamine plasma concentrations were measured using high-performance liquid chromatography. Plasma dopamine concentration increased in all patients and reached a steady state at T2 (T2 = 76.41 +/- 16.84 ng/ml). Dopamine induced a concentration-dependent increase in urinary output (T0 = 0.45 +/- 0.14; T1 = 1.49 +/- 1.11; T2 = 2.34 +/- 1.44; T3 = 1.57 +/- 0.57; T4 = 0.85 +/- 0.7 ml/kg/hr). Three patients did not have an enhanced urinary output after dopamine infusion; they did have a prolonged clamping time and operation time (162 +/- 24 and 570 +/ 30 min, respectively). We conclude that low dose dopamine induces a dose-dependent increase of urinary output. This phenomenon also has been found in patients when their plasma concentration had not yet reached the steady-state. Lack of responsiveness to dopamine suggests a renal function impairment probably due to the prolonged aortic clamping time.