Is a combination of Isoflurane with nitroglycerine better than halothane with nitroglycerine for controlled hypotension in spine surgery: A comparative clinical evaluation?

摘要

Methods and techniques for producing deliberate hypotension has been changing continuously and evolving, not only as the result of the discovery of newer agents and techniques but also from an improved understanding of the underlying physiological changes. This study was conducted at Himalayan Institute Of Medical Sciences in 90 patients of either sex undergoing spinal surgery in the age group 21-70years of ASA grade I,II. They were divided randomly into three groups of 30 patients each group I (Nitroglycerine: NTG) Group II (halothane +NTG) and Group III (Isoflurane +NTG). Various hemodynamic, physiological parameters and were recorded. Heart rate was maximally increased (p<0.01) at 15 min after starting NTG (79?5.11 to 92.9?6.35 beats /min) in group I. The use of combinations agents was hemodynamically more stable. There was significant decrease in rate pressure product in all the three groups. The order of time taken to achieve desired levels of Systolic blood pressure was groupII> Group III> Group I. The order of time taken to achieve near normotensive levels was group II> Group III> Group I. Thus we can conclude that better cardiovascular and hemodynamic stability can achieve the best outcome for the patient, using deliberate hypotensive technique with NTG and isoflurane combination. Introduction Virtually all surgeries involve cutting of the blood vessels which will obviously result in bleeding. Frequently bleeding is so excessive as to endanger the life of the patient. A more complex problem is the persistent ooze that makes certain operations difficult or impossible. 1 Deliberate hypotension is an attempt to produce a controlled and safe reduction in the intravascular pressure, obtaining favorable outcome of the surgery. By enhancing the visualization of the surgical field, hypotension allows accurate delineation of lesions thereby causing fewer traumas to the delicate structures. With its aid intricate operations may be performed more easily, more exactly and therefore more successfully. 2,3 The control of bleeding and the maintenance of an adequate circulating blood volume are fundamental tenets of sound surgical practices, but such control is not always easy. The use of circulatory adjustments to achieve a desirable hemodynamic state is a cornerstone of perioperative anaesthetic management. 4,5,6 These maneuvers are mostly accomplished by physiologic and pharmacological manipulations and thus are within the purview of the anesthesiologists.Deliberate hypotension is defined as the intentional reduction of the systemic perfusion pressure. Deliberate hypotension is defined as reduction in systolic blood pressure (SBP) to 80-90mm Hg (30% decrease in the SBP from the baseline pressure) or a decrease in the mean arterial pressure (MAP) to 50-65 mm Hg in normotensive patients. 7 Hypotension is broadly achievable by vasodilatation and /or reduced myocardial contractility 8,9,10 . Various inhalational agents (Halothane , isoflurane , sevoflurane,) 11,12 and intravenous agents (pentamethonium iodide,nitroglycerine, labetolol, esmolol, adenosine) 13,14,15,16,17,18 are usually used to achieve this hypotension. Best attempt is made to maintain adequate organ perfusion at low perfusion pressure (During hypotensive state). This study considers some of the anaesthetic choices and ideas behind attempts for better cardiovascular and hemodynamic stability to achieve the best outcome for the patient, using deliberate hypotensive technique.AimThe aim of this study was to study hemodynamic changes by using various drugs and combinations used for producing deliberate hypotension. To find out the safer dose limits in order to achieve target safe hypotension. To study side effects and complications of the drugs used for hypotension. To conclude upon merits and demerits of deliberate hypotension. Material & Methods This study was conducted in Department of Anesthesiology and Intensive care, Himalayan Institute of Medical Sciences, Swami Rama