Orthostatic Hemodynamic Changes in Brain Damage

Abstract

Aim: to study orthostatic hemodynamic changes in patients with chronic disorders of consciousness after critical brain damage.Materials and methods. We studied 30 patients (10 women and 20 men) with chronic disorders of consciousness after severe brain damage aged 45±7 years, 10 of which were in the vegetative state (VS) and 20 had the minimally conscious state (MCS). The main causes of brain damage were traumatic brain injury (53% of patients) and cerebrovascular accidents (CVA) (23.3%). The rest of the patients had posthypoxic encephalopathy or were after brain tumor removal surgery. Passive orthostatic test (POT) 0° to 60° to 0° was performed using an electrically driven tilt table (Vario Line). Hemodynamic monitoring during the verticalization was done using a non-invasive oscillometric recording of blood pressure on the brachial artery, stroke volume (SV) and cardiac minute output (CMO) were measured by impedance cardiography with the multifunctional «Task Force Monitor 3010i» (CNSystem, Austria). Data were statistically analyzed using the Statistica 10 software package.Results. Orthostatic hemodynamic stability was found in 26 out of 30 patients with chronic disorders of consciousness after critical brain damage. It was manifested by stable systolic blood pressure (SBP) in tilted orthostatic and horizontal position (120.7±2.2 and 121.1±3.6 mmHg, respectively, P>0.05). Orthostatic hypotension was observed in 3 patients and postural tachycardia syndrome (PTS) in one patient. We compared orthostatic hemodynamic changes in the studied cohort versus published data on orthostatic hemodynamic changes uncluding POT revealed in patients with severe brain damage examined before and after brain death.Conclusion. Orthostatic stability of blood circulation can be maintained for a short period of time in patients surviving after critical diffuse brain damage associated with chronic disorders of consciousness. Critical brain damage resulting in brain death associates with a significant reduction of all hemodynamic parameters and severe orthostatic hypotension with restoration of initial blood pressure values when the patient is returned to the horizontal position.

Keywords

• critical damage
• brain
• hemodynamics
• orthostatic test
• spinal regulation of circulation
• orthostatic hypotension
• brain death