Plateau Waves and Baroreflex Sensitivity in Patients with Head Injury: A Case Study

The study aimed to investigate baroreceptor reflex sensitivity in a patient with head injury for whom plateau waves of intracranial pressure (ICP) were recorded. Baroreflex sensitivity index was separately estimated on top of plateau waves and during intermediate intervals between two consecutive waves. The EuroBaVar data set was utilized to verify and validate the results. A very high baroreflex sensitivity associated with dominant parasympathetic activity was observed spontaneous to the acute elevations of ICP. The high vagal afferent discharge was found to be suggestive for the high firing rate of carotid baroreceptors and probably an active Cushing reflex mechanism during plateau waves

Plateau Waves and Baroreflex Sensitivity in Patients with Head Injury: A Case Study

The study aimed to investigate baroreceptor reflex sensitivity in a patient with head injury for whom plateau waves of intracranial pressure (ICP) were recorded. Baroreflex sensitivity index was separately estimated on top of plateau waves and during intermediate intervals between two consecutive waves. The EuroBaVar data set was utilized to verify and validate the results. A very high baroreflex sensitivity associated with dominant parasympathetic activity was observed spontaneous to the acute elevations of ICP. The high vagal afferent discharge was found to be suggestive for the high firing rate of carotid baroreceptors and probably an active Cushing reflex mechanism during plateau waves

Pulse Wave Velocity in Patients with Severe Head Injury: A Pilot Study

The study aimed to determine the potential of pulse wave velocity measurements to reflect changes in compliant cerebral arteries/arterioles in head injured patients. The approach utilizes the electrocardiogram and intracranial pressure signals to measure the wave transit time between heart and cranial cavity. Thirty five clinical records of nineteen head injured patients, with different levels of cerebrovascular pressurereactivity response, were investigated through the study. Results were compared with magnitude of normalized transfer function at the fundamental cardiac frequency. In patients with intact cerebrovascular pressure-reactivity, magnitude of normalized transfer function at the fundamental cardiac component was found to be highly correlated with pulse wave transit time

Cerebrovascular Mechanical Properties and Slow Waves of Intracranial Pressure in TBI Patients

Myogenic autoregulation of cerebral blood flow is one of the mechanisms affecting cerebral hemodynamics. Short or long-lasting changes in intracranial pressure (ICP) are believed to reveal the responses of the cerebral system to myogenic stimuli. Through the incorporation of a theoretical model into the experimental measurements of cerebrovascular distensibility and compliance in patients with traumatic brain injury (TBI), the current study is an attempt to explain ICP dynamics in either presence or absence of cerebral autoregulation. The pulse wave velocity and transfer function between arterial blood pressure and ICP were utilized as the major tools to reflect variations in the mechanical properties of distant cerebral artries/arteriols. The results imply that different states of cerebral autoregulation and associated regimes within the cerebrovascular system can lead to different types of interrelationship between the slow variations of ICP, cerebral arterial distensibility, and compliance. Consequently, each of these classes may require different types of treatment on patients with TBI

Normalized Power Transmission between ABP and ICP in TBI

A new approach to study the pulse transmission between the cerebrovascular bed and the intracranial space is presented. In the proposed approach, the normalized power transmission between ABP and ICP has got the main attention rather than the actual power transmission. Evaluating the gain of the proposed transfer function at any single frequency can reveal how the percentage of contribution of that specific frequency component has been changed through the cerebrospinal system. The gain of the new transfer function at the fundamental cardiac frequency was utilized to evaluate the state of the brain in three TBI patients. Results were assessed using the reference evaluations achieved by a novel CT scanbased scoring scheme. In all three study cases, the gain of the transfer function showed a good capability to follow the trend of the CT scores and describe the brain state. Comparing the new transfer function with the traditional one and also the index of compensatory reserve, the proposed transfer function was found more informative about the state of the brain in the patients under study