Effect of L-NAME, an inhibitor of nitric oxide synthesis, on cardiopulmonary function in human septic shock

STUDY OBJECTIVES: We tested the effects of continuous infusion of N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, on cardiovascular performance and pulmonary gas exchange in patients with hyperdynamic septic shock. DESIGN: Prospective clinical study. SETTING: ICU of a university hospital. PATIENTS: Eleven critically ill patients with severe refractory septic shock. INTERVENTIONS: Standard hemodynamic measurements were made and blood samples taken before, during, and after 12 h of continuous infusion of 1 mg/kg/h of L-NAME. MEASUREMENTS AND RESULTS: Continuous infusion of L-NAME increased mean arterial pressure (MAP) from 65+/-3 (SEM) to 93+/-4 mm Hg and systemic vascular resistance (SVR) from 962+/-121 to 1,563+/-173 dyne x s x cm(-5)/m2. Parallel to this, cardiac index (CI) decreased from 4.8+/-0.4 to 3.9+/-0.4 L/min/m2 and myocardial stroke volume (SV) was reduced from 43+/-3 to 34+/-3 mL/m2. Left ventricular stroke work was increased in the first hour of L-NAME infusion from 31+/-3 to 43+/-4 g x m/m2 (all p<0.01 compared with baseline). Heart rate, cardiac filling pressures, and right ventricular stroke work did not change significantly (p>0.05). L-NAME increased the ratio of arterial PO2 to the fraction of inspired O2 from 167+/-23 to 212+/-27 mm Hg (p<0.05). Venous admixture (QVA/QT) was reduced from 19.4+/-2.6% to 14.2+/-2.1% (p<0.05) and oxygen extraction ratio increased from 21.1+/-2.4% to 25.3+/-2.7% (p<0.05). Oxygen delivery (DO2) was reduced following L-NAME, whereas oxygen uptake and arterial lactate and pH were unchanged. CONCLUSIONS: Prolonged inhibition of NO synthesis with L-NAME can restore MAP and SVR in patients with severe septic shock. Myocardial SV and CI decrease, probably as a result of increased afterload, since heart rate and stroke work were not reduced. L-NAME can improve pulmonary gas exchange with a concomitant reduction in QVA/QT. L-NAME did not promote anaerobe metabolism despite a reduction in DO2

A helical PTFE arteriovenous access graft to swirl flow across the distal anastomosis: results of a preliminary clinical study.

Intimal hyperplasia develops preferentially in regions where the blood flow is stagnant and wall shear stress low. The small amplitude helical geometry of the SwirlGraft was designed to ensure physiological-type swirling flow, and thus suppress the triggers. We report the first conceptual testing of the SwirlGraft. Primary, assisted primary and secondary patency rates at 6 months in 20 patients were 57.9+/-11.4%, 84.4+/-8.3% and 100+/-0.0%. There was angiographic evidence of reduction of helical geometry in a proportion of the grafts. The helical graft is associated with high assisted primary and secondary patency. Elaboration of the surgical implantation techniques and an improved SwirlGraft design can be expected to exploit the advantages of the helical concept

Three Year Single Centre Experience with the AneuRx Aortic Stent Graft

AbstractObjectives: to report the mid-term single-centre experience with the AneuRx self-expandable nitinol stentgraft for endovascular aneurysm repair. Patients and Methods: between December 1996 and January 2000 a total of 128 patients were treated with an AneuRx bifurcated stentgraft. Of these, 77 patients had a minimum follow-up of 12 months. Patient operative and follow-up data were prospectively gathered. Results: two (3%) conversions were necessary. Median hospital stay was 3 days. One superficial wound infection occurred. Periprocedural (30 days) mortality was 5% (four patients). Three graft occlusions were noted of which two required treatment. Fifteen patients developed 18 endoleaks (six type 1, eight type 2 and four type 3). Type 1 and type 3 endoleaks were treated by extension cuffs. Four type 2 endoleaks were treated with embolisation or direct lumbar puncture. Two-year freedom from endoleak was 76%. Graft migration occurred in six cases, resulting in a 2-year freedom from migration of 90%, kinking only once. Conclusions: endovascular AAA treatment is feasible and so far mid-term results are without major problems. Extensive follow-up is essential as secondary problems may occur later. Long-term results are to be awaited