Tissue Hypoperfusion is a condition of imbalance between oxygen delivery and consumption. It leads to tissue damage if persists, particularly in critically ill patients or during long surgeries. It is important to prevent vasoconstriction of microvessels preluding tissue hypoperfusion and injury.Objectives: This study aims to evaluate the effects of low-dose continuous vasodilator agents on patients susceptible to hypoperfusion damage.
Design: This is a double-blind randomized controlled study of 56 patients undergoing long orthopedic surgery (more than 120 minutes).The patients divide randomly into two groups of 28 patients (receivers of nitroglyecerin - dubotamine and control); each group also randomizes to receive general and epidural anesthesia in two groups of 14 patients.
inclusion criteria : Patient's satisfaction with participating in the study; Patients in group I and II ASA Score; No history of Liver or Renal insufficiency, DM, HTN, Heart and Pulmonary disease; No acid-base disorders; No TNG, dubotamine or anesthetic drugs allergy; No emergent surgery; No pregnancy; No contraindications of TNG(Idiopathic hypertrophic subaortic stenosis, post myocardial infarction hypertension); No contraindications of dubotamine( myocardial infarction, open angle glaucoma, allergy to phosphodiesterase inhibitors, cerebral hemorrhage, ICP rise, severe anemia, orthostatic hypotention, sildenafil use in restrictive cardiomyopathy)
Exclusion Criteria: Resistant drop in blood pressure with mean arterial pressure less than 60; Increasing blood pressure needing therapeutic interventions more than predicted in study method.
Setting and conduct: Treatments in intervention group includes trinitroglycerin 0.1 µg/kg/min and dobutamine 1.5-2 µg/kg/min during surgery. The control group receives standard anesthetic and analgesic techniques beside 100 cc normal saline as placebo. All the patients in operation room are under monitoring, NIBP, IBP, pulse oxymetry and pulse rate measuring.Arterial Blood Gas is checked in the start of anesthesia, per hour during surgery and at the end.Finally data is gathered and analyzed in SPSS and hypoperfusion markers such as pH, bicarbonate, base excess, pO2, pCO2 and oxygen saturation are compared in the groups.