Non-invasive assessment of cerebral perfusion pressure in brain injured patients with moderate intracranial hypertension

• Published in: British journal of anaesthesia : BJA Vol. 94; no. 2; pp. 216 - 221
• Main Authors: Edouard, A.R., Vanhille, E., Le Moigno, S., Benhamou, D., Mazoit, J.-X.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2005; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Adult; Anesthesia; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood Flow Velocity; Blood Pressure; brain; Brain Injuries - complications; Brain Injuries - diagnostic imaging; Brain Injuries - physiopathology; brain, cerebral perfusion pressure; brain, intracranial pressure; Carbon Dioxide - blood; cerebral perfusion pressure; Cerebrovascular Circulation; complications; complications, traumatic brain injury; Female; Humans; Injury Severity Score; Intracranial Hypertension - diagnostic imaging; Intracranial Hypertension - etiology; Intracranial Hypertension - physiopathology; Intracranial Pressure; jugular venous oxygen saturation; Male; Medical sciences; Middle Aged; Middle Cerebral Artery - diagnostic imaging; Middle Cerebral Artery - physiopathology; monitoring; monitoring, jugular venous oxygen saturation; Monitoring, Physiologic - methods; monitoring, transcranial Doppler ultrasonography; Partial Pressure; Prospective Studies; transcranial Doppler ultrasonography; traumatic brain injury; Ultrasonography, Doppler, Transcranial - methods; monitoring, transcranial Doppler ultrasonography; complications, traumatic brain injury; brain, cerebral perfusion pressure; brain, intracranial pressure; monitoring, jugular venous oxygen saturation; traumatic brain injury; monitoring; Variability; Carbon dioxide; Intracranial pressure; Anesthesia; Complication; Arterial pressure; Monitoring; Sonography; Human; Nervous system diseases; Oxygen; Head; Estimation; Intracranial hypertension; Saturation; brain; cerebral perfusion pressure; brain; Cerebral disorder; intracranial pressure; complications; transcranial Doppler ultrasonography; jugular venous oxygen saturation; monitoring; Central nervous system disease; Flow velocity; Head trauma; Comparative study
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/aei034

A non-invasive estimation of cerebral perfusion pressure (CPP) using transcranial Doppler sonography was assessed in brain-injured patients by comparing conventional measurements of CPP (difference between mean arterial pressure and intracranial pressure) (CPPm) with the difference between APmean and the critical closing pressure of the cerebral circulation (CPPe). Twenty adults with bilateral and diffuse brain injuries were included in the study. CPPe was estimated using a formula combining the phasic values of flow velocities and arterial pressure. In group A (n=10) the comparison was repeatedly performed under stable conditions. In group B (n=10) the comparison was performed during a CO2 reactivity test. Covariance analysis was used to assess the relationships. In group A, CPPe and CPPm were correlated (slope, 0.76; intercept, +10.9; 95% CI, −3.5 to +25.4). During the increase in intracranial pressure (group B) (+1.9 (sd 1.5) mm Hg per mm Hg of PE’co2) the relationship persisted (slope, 0.55; intercept, +32.6; 95% CI, +16.3 to +48.9) but the discrepancy between the two variables increased as reflected by the increase in bias and variability. Non-invasive estimation of CPP can be used for brain monitoring of head-injured patients, but the accuracy of the method may depend on the level of intracranial hypertension.