Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of controlled hypotension (mean arterial pressure 60 mmHg) induced by sodium nitroprusside and trimethaphan on systemic circulation and myocardial oxygen consumption was studied in 7 anaesthetized closed chest dogs. The hypotensive effect of both drugs was primarily mediated by a reduction in total peripheral resistance. No change in cardiac output was observed. Stroke volume decreased in the presence of tachycardia. Left ventricular max dp/dt remained unaffected during sodium nitroprusside hypotension and was reduced by trimethaphan. Max dp/dt, load data and heart rate indicated that trimetaphan possesses negative inotropic properties. Sodium nitroprusside induced a hyperperfusion of the heart with a marked decrease in myocardial arteriovenous difference in oxygen. Myocardial oxygen consumption remained unchanged. Trimethaphan, on the other hand, induced only small increments in coronary blood flow and a rise in the arteriovenous difference in oxygen of the heart. This resulted in a higher myocardial oxygen consumption (+16%). Cardiac efficiency was lessened by trimethaphan and remained unaffected in the presence of sodium nitroprusside. As sodium nitroprusside neither affects myocardial oxygen consumption nor alters myocardial contractility, we conclude that sodium nitroprusside has advantages over trimethaphan in the management of controlled hypotension and in the therapy of hypertensive crisis and cardiogenic shock.
 ...
PMID:[The effects of sodiumnitroprusside and trimethaphan induced hypotension on haemodynamics and myocardial oxygen consumption (author's transl)]. 125 27

By combining surgical and anesthetic techniques that minimize blood loss with the use of autotransfusion, it should now be possible to complete a routine posterior spinal fusion without using allogeneic blood transfusions. Surgical efforts should include careful preoperative planning, positioning with the abdomen hanging free, use of topical hemostatic agents, and decortication late in the procedure. Preoperatively donated autogeneic blood or reclaimed red cells from suction can take the place of allogeneic transfusions. Blood loss during scoliosis surgery correlates closely with left ventricular stroke work index (LVSWI), a measure of blood flow calculated from systemic vascular resistance, cardiac output, and heart rate. All of these parameters are under the anesthesiologist's control, making him the primary determinant of blood loss in scoliosis surgery. Induced hypotensive anesthesia may be ineffective in controlling blood loss if the cardiac output or heart rate is high. Halothane, a commonly used hypotensive agent, is not very useful for scoliosis surgery because spinal cord monitoring and wake-up testing are not possible. Rebound hypertension has been noted with the use of sodium nitroprusside. Trimethaphan works well clinically but experimentally it reduces spinal cord blood flow, which may increase the risk of spinal cord injury.
 ...
PMID:Control of blood loss during scoliosis surgery. 328 Feb 5