Review: pathophysiology of intracranial hypertension and noninvasive intracranial pressure monitoring

Abstract

Measurement of intracranial pressure (ICP) is crucial in the management of many neurological conditions. However, due to the invasiveness, high cost, and required expertise of available ICP monitoring techniques, many patients who could benefit from ICP monitoring do not receive it. As a result, there has been a substantial effort to explore and develop novel noninvasive ICP monitoring techniques to improve the overall clinical care of patients who may be suffering from ICP disorders. This review attempts to summarize the general pathophysiology of ICP, discuss the importance and current state of ICP monitoring, and describe the many methods that have been proposed for noninvasive ICP monitoring. These noninvasive methods can be broken down into four major categories: fluid dynamic, otic, ophthalmic, and electrophysiologic. Each category is discussed in detail along with its associated techniques and their advantages, disadvantages, and reported accuracy. A particular emphasis in this review will be dedicated to methods based on the use of transcranial Doppler ultrasound. At present, it appears that the available noninvasive methods are either not sufficiently accurate, reliable, or robust enough for widespread clinical adoption or require additional independent validation. However, several methods appear promising and through additional study and clinical validation, could eventually make their way into clinical practice.

Isoflurane maintenance of neuroanaesthesia in two dogs with hydrocephalus and syringohydromyelia undergoing ventriculoperitoneal shunt surgery

“…Non-invasive ICP monitoring based on fluid dynamic, otic, ophthalmic and electrophysiological principles has been described in humans but remains to be validated in veterinary patients. 41 Emergence from general anaesthesia, in both cases, was calm without coughing and haemodynamic responses to tracheal extubation. Within the postoperative period of 36 hours, case 1 developed severe hypertension with a SAP of 202±14 mmHg and an HR of 94±20 bepm.…”

“…Due to the invasiveness, high cost and required expertise, we were not able to apply this monitoring technique. Non‐invasive ICP monitoring based on fluid dynamic, otic, ophthalmic and electrophysiological principles has been described in humans but remains to be validated in veterinary patients 41…”

Intracranial Pressure Waveform: History, Fundamentals and Applications in Brain Injuries

“…Thus, ICP is influenced by many physiological factors from extra and intracranial compartments. Moreover, factors as age, body posture, time of day as well as the clinical condition also are considerable variables, although in absence of disturbances, mean ICP is kept mostly within a range between 7 and 15 mmHg for adults, 3 and 6 mmHg in children, and between 1.5 and 6 mmHg in term infants [18].…”

The "Brain Stethoscope": A Non-Invasive Method for Detecting Elevated Intracranial Pressure

“…Elevated intracranial pressure (ICP) is commonly screened for in multiple conditions including hydrocephalus, pseudotumor cerebri, and trauma [ 1 ]. The standard of practice for measuring ICP involves lumbar puncture and measuring the cerebrospinal fluid opening pressure via manometry or through a direct intracranial interface with an external ventricular drain saline column transduced by a strain gauge [ 2 ].…”