Autoregulation of Blood Cerebral Circulation and Methods of Its Correction in Patients with Spinal Trauma

Abstract

Introduction Adequate blood flow to the brain is provided by the mechanisms of autoregulation. The term “autoregulation of cerebral circulation” (ARCC) is used to denote the possibility of homeostatic systems of an organism to maintain tissue cerebral blood flow at a constant level regardless of changes in the system AP, metabolism, and the effects of vasoactive agents. ARCC is easily violated mechanism which may be affected as a result of hypoxia, hypercapnia, a sudden increase or decrease in AP. Breakdown of autoregulation is a condition in which tissue cerebral blood flow passively depends on the system AP. Materials and Methods The research was conducted in the Department of Anesthesiology and Intensive Care of “Clinical Mine Hospital” from 2011 to 2012. Patients with severe spinal trauma were selected for the study. On the background of the basic therapy and infusion therapy by using solutions of colloids and crystalloid, solutions of inotropic and vasoactive agents (dobutamine/phenylephrine; dopamine/phenylephrine) in cases of arterial hypotonia and solution of Urapidil in cases of arterial hypertension were infused. Dynamic measurements of the parameters of central hemodynamics by tetrapolar rheography (MAP, CI, the General peripheral vascular resistance), assessment of CVP, and study of cerebral hemodynamics using transcranial Doppler device to achieve a maximum level of consciousness (GCS, BIS-monitoring). Additional parameters of quality of infusion therapy were indicators of hematocrit, total blood protein, osmolarity, and pace of diuresis. A total of 37 patients in the acute period of spinal trauma who were admitted to the Department of Anesthesiology and Intensive Care were examined. In the first group, 22 patients with craniocerebral injury, whose level of consciousness was 9 to 12 points GCS were included. The second group included 15 patients with craniocerebral injury, whose level of consciousness was 5 to 8 points GCS. Results The patients of group 1 have linear blood flow speed (LBFS) that was not significantly changed, ARCC was saved. In 11 patients of group 2 (73%), significant reduction of cerebral blood flow and impaired ARCC were initially recorded. Conclusion The attempt of introducing of method of ARCC diagnostic by using transcranial dopplerography, BIS-monitoring, and tetrapolar rheography was undertaken. This method allows to optimize brain blood flow through the application of vasoactive and inotropic agents and volemic load under the control of the CVP and urine output. Patients in the acute period of spinal trauma, regardless of the severity of injury, may have well-functioning and broken ARCC. Noninvasive assessment of the state of ARCC according to the LBFS depending on MAP can be used as an alternative criterion for predicting the course of the acute period of spinal trauma and efficiency of treatment of patients. Disclosure of Interest None declared References Andrew PJD. What is the optimal perfusion pressure after brain injury: a review of the evidence with emphasis on arterial pressure. Acta Anaesthesiol Scand 1995;39(Suppl 105):112–114 Asgeirsson B, Grände PO, Nordström CH. A new therapy of post-trauma brain oedema based on haemodynamic principles for brain volume regulation. Intensive Care Med 1994;20(4):260–267 Asgeirsson B, Grande PO, Nordstrom CH. The Lund concept of post-traumatic brain oedema therapy. Acta Anaesthesiol Scand 1995;39(Suppl 105):103–106 Drummond JC, Oh YS, Cole DJ, Shapiro HM. Phenylephrine-induced hypertension reduces ischemia following middle cerebral artery occlusion in rats. Stroke 1989;20(11):1538–1544 Gentleman D. Preventing secondary brain damage after head injury: a multidisciplinary challenge. Injury 1990;21(5):305–308