'Long' pressure reactivity index (L-PRx) as a measure of autoregulation correlates with outcome in traumatic brain injury patients.
Summary of "'Long' pressure reactivity index (L-PRx) as a measure of autoregulation correlates with outcome in traumatic brain injury patients."
BACKGROUND:
Cerebral autoregulation and, consequently, cerebrovascular pressure reactivity, can be disturbed after traumatic brain injury (TBI). Continuous monitoring of autoregulation has shown its clinical importance as an independent predictor of neurological outcome. The cerebral pressure reactivity index (PRx) reflects that changes in seconds of cerebrovascular reactivity have prognostic significance. Using an alternative algorithm similar to PRx, we investigate whether the utilization of lower-frequency changes of the order of minutes of mean arterial blood pressure (MAP) and intracranial pressure (ICP) could have a prognostic value in TBI patients. MATERIALS AND
METHODS:
Head-injured patients requiring continued advanced multimodal monitoring, including hemodynamic, ICP and microdialysis (MD) monitoring, were analyzed retrospectively. A low-frequency sample pressure reactivity index (L-PRx) was calculated, using 20-min averages of MAP and ICP data as a linear Pearson's correlation. The mean values per patient were correlated to outcome at 6 months after injury. Differences of monitoring parameters between non-survivors and survivors were compared.
RESULTS:
A total of 29 patients (mean age 37.2 years, 26 males) suffering from TBI were monitored for a mean of 109.6 h (16-236 h, SD ± 60.4). Mean L-PRx was found to be of 0.1 (-0.2 to 0.6, SD ± 0.20), six patients presented impaired (>0.2) values. The averaged L-PRx correlated significantly with ICP (r = 0.467, p = 0.011) and 6-month outcome (r = -0.556, p = 0.002). Significant statistical differences were found in L-PRx, cerebral perfusion pressure (CPP), lactate, and lactate-pyruvate ratio when comparing patients who died (n = 5) and patients who survived.
CONCLUSIONS:
L-PRx correlates with the 6-month outcome in TBI patients. Very slow changes of MAP and ICP may contain important autoregulation information. L-PRx may be an alternative algorithm for the estimation of cerebral autoregulation and clinical prognosis.
Affiliation
Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany, Renan.Sanchez-Porras@med.uni-heidelberg.de.
Journal Details
This article was published in the following journal.
Name: Acta neurochirurgica
ISSN: 0942-0940
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22743796
- DOI: http://dx.doi.org/10.1007/s00701-012-1423-0
Medical and Biotech [MESH] Definitions
Pressure Ulcer
An ulceration caused by prolonged pressure on the SKIN and TISSUES when one stay in one position for a long period of time, such as lying in bed. The bony areas of the body are the most frequently affected sites which become ischemic (ISCHEMIA) under sustained and constant pressure.
Lung Compliance
The capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562)
Catheterization, Swan-ganz
Placement of a balloon-tipped catheter into the pulmonary artery through the antecubital, subclavian, and sometimes the femoral vein. It is used to measure pulmonary artery pressure and pulmonary artery wedge pressure which reflects left atrial pressure and left ventricular end-diastolic pressure. The catheter is threaded into the right atrium, the balloon is inflated and the catheter follows the blood flow through the tricuspid valve into the right ventricle and out into the pulmonary artery.
Hypertensive Encephalopathy
Brain dysfunction or damage resulting from sustained MALIGNANT HYPERTENSION. When BLOOD PRESSURE exceeds the limits of cerebral autoregulation, cerebral blood flow is impaired (BRAIN ISCHEMIA). Clinical manifestations include HEADACHE; NAUSEA; VOMITING; SEIZURES; altered mental status (in some cases progressing to COMA); PAPILLEDEMA; and RETINAL HEMORRHAGE.
Vascular Capacitance
The measure of a BLOOD VESSEL's ability to increase the volume of BLOOD it holds without a large increase in BLOOD PRESSURE. The vascular capacitance is equal to the change in volume divided by the change in pressure.
PubMed Articles
BACKGROUND AND PURPOSE: In patients with subarachnoid hemorrhage, the assessment of cerebral autoregulation aids in prognosis as well as detection of vasospasm. Mx is a validated index of cerebral aut...
Monitoring Cerebral Blood Flow Pressure Autoregulation in Pediatric Patients During Cardiac Surgery.
BACKGROUND AND PURPOSE: The limits of cerebral blood flow-pressure autoregulation have not been adequately defined for pediatric patients. Mean arterial blood pressure below these limits might contrib...
BACKGROUND AND PURPOSE: Individualizing mean arterial blood pressure targets to a patient's cerebral blood flow autoregulatory range might prevent brain ischemia for patients undergoing cardiopulmonar...
BACKGROUND: Clinical monitoring of cerebral blood flow (CBF) autoregulation in patients undergoing liver transplantation may provide a means for optimizing blood pressure to reduce the risk of brain i...
The purpose of this study was to examine the effects of hyperventilation or hyperoxia on cerebral hemodynamic parameters over time in patients with severe traumatic brain injury (TBI). We prospectivel...
Clinical Trials
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vas...
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vas...
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vas...
Choroidal Blood Flow Regulation During Isometric Exercise: Effects of Ca2+-Channel Blockade
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vas...
Background Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve...
