Nitric oxide regulates basal systemic and pulmonary vascular resistance in healthy humans

LITERATURE REVIEW FredeticX: W. Campbell, MD, Section Editor

SCIENTIFIC ARTICLES

monary complications. The authors conclude anesthesia is safer than general anesthesia.

Schonberger JPAM, Van Oeveren W, Berdee JJ, et al: Systemic blood activation during and after autotransfusion. Ann Thorac Surg 56:1256-1262,1994 Thromboxane, fibrinogen degradation products, complement split product C3A, and elastase were elevated in shed blood and, with the exception of C3A, in the circulating blood of autotransfused patients (N = 18). No markers of blood activation were measured in control patients (N = 10). The degree of systemic inflammatory reaction was related to the type of autotransfusion system and the amount of infused shed blood. A Dideco (D 742, Dideco SpA, Mirandola, Italy) with a filter having a larger contact area evoked more inflammatory response than did a Sorin (CRF 28, Sorin, Biomedica SpA, Sallugia, Italy) system with a smaller filter. Patients transfused from the Dideco system had larger shed blood loss during and after autotransfusion, required more colloid/ crystalloid solution, and received more allogenic blood products compared to Sorin-infused patients when more than 800 mL of shed blood was infused. In a related study in the same journal (Hannes W, Keilich M, Koster W, et al: Shed blood autotransfusion influences ischemiasensitive laboratory parameters after coronary operations. Ann Thoruc Surg 57:1289-1294, 1994), creatine kinase, creatine kinase MB, 2-hydroxybutyrate dehydrogenase, lactate dehydrogenase-1, troponin-T, myoglobin, and glutamic-oxaloacetic transaminase levels were significantly elevated in patients with postoperative autotransfusion compared to controls although there were no electrocardiographic signs of myocardial ischemia. Postoperative autotransfusion of mediastinal shed blood may produce falsepositive chemical markers of perioperative myocardial ischemia.

Allen BT, Anderson CB, Rubin BG, et al: The influence of anesthetic technique on perioperative complications after carotid endarterectomy. J Vast surg 19:834-843,1994 This is a retrospective, nonrandomized comparison in consecutive patients undergoing carotid endarterectomy with general anesthesia (N = 361) or superficial and deep cervical plexus blocks (N = 318). Symptomatic carotid artery disease was more often the indication for surgery in patients receiving general anesthesia (68.4%) than in those managed with a cervical block anesthetic (56.6%). Perioperative stroke rate and stroke-death rate were not different between the anesthetic groups. A carotid artery shunt was used in 19.2% patients using a cervical plexus block and 42.1% patients receiving general anesthesia. Use of cervical block anesthesia was associated with a significantly shorter operative time, fewer perioperative cardiopulmonary complications, and shorter postoperative hospital stay when compared with general anesthesia. Multivariate risk factor analysis indicated that operative time greater than 3 hours (P = O.OOOS), use of carotid artery shunt (P = 0.03), age greater than 75 years (P = 0.06), and general anesthesia (P = 0.13) were risk factors for perioperative cardiopul-

Journal of Cardiothoracic and VascularAnesthesia,

that cervical

block

Cook DJ, Oliver WC Jr, Orszulak TA, Daly RC: A prospective, randomized comparison of cerebral venous oxygen saturation during normothermic and hypothermic cardiopulmonary bypass. J Thorac Cardiovasc Surg 107:1020-1029,1994 Jugular bulb oximetry was used during normothermic (37”C, N = 26) or hypothermic (27”, N = 26) cardiopulmonary bypass with alpha-stat pH management in 52 patients undergoing coronary bypass surgery. Cerebral venous desaturation (oxygen saturation I 50%) was observed in 54% of normothermic patients and 12% of hypothermic patients during bypass. In the normothermic group, cerebral desaturation occurred primarily in early bypass. Three episodes of desaturation in hypothermic patients occurred during rewarming. Cerebral oxygen consumption was greater in the normothermic group than in the hypothermic patients. It remains to be seen whether these differences in cerebral physiologic state result in outcome differences.

Hird RB, Crawford FA Jr, Mukherjae R, et al: Effects of protamine on myocyte contractile function and beta-adrenergic responsiveness. Ann Thorac Surg 56:1066-1075,1994 Porcine myocyte shortening and velocity of shortening were examined using videomicroscopy at baseline, and in the presence of protamine (80 pg/mL), heparin (8 U/mL), and after heparin neutralization by protamine. In the presence of protamine alone, percent shortening and velocity of shortening fell by more than one third from baseline values and myocyte beta-adrenergic responsiveness was blunted. Heparin alone or heparin-protamine complex produced no change in myocyte contractility or beta-adrenergic responsiveness.

Stamler JS, Lob E, Roddy MN, et al: Nitric oxide regulates basal systemic and pulmonary vascular resistance in healthy humans. Circulation 892035 2040,1994 Celermajer DS, Dollery C, Burch M, Beanfield JE: Role of endothelium in the maintenance of low pulmonary vascular tone in normal children. Circulation 89:2041-2044,1994 A nitric oxide synthase inhibitor, LNMMA, was administered to healthy volunteers in these two studies. Systemic LNMMA administration decreased serum nitric oxide levels, increased systemic and pulmonary vascular resistance, and reduced stroke volume in the first study. Infusion of the nitric oxide antagonist into a segmental pulmonary artery of healthy children led to a dosedependent fall in pulmonary flow velocity. It appears the basal

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