4 Types Intracranial Pressure Monitoring Devices and Techniques

The human brain is a delicate organ which is affected even by slight changes in the skull. A normal human skull is a rigid and sturdy compartment comprising of the brain and other items like cerebrospinal fluids, blood, etc. All these components exert a pressure on the skull. This pressure, especially the one exerted by cerebrospinal fluid inside the skull on the brain tissue is known as intracranial pressure. The normal volume inside a skull i.e., the intracranial volume is around 1700 ml and the normal range of intracranial pressure is about 5-15 mmHg. While cerebrospinal fluid production occurs to the tune of 500-600 ml per day, the absorption of this fluid results in bringing down this volume up to 150ml. Thus, an equilibrium exists between the rate of production and rate of absorption of the cerebrospinal fluid, which helps in maintaining the pressure exerted by the fluid on the brain tissues. However, if this equilibrium is disturbed and the rate of absorption falls, the excess of the cerebrospinal fluid starts exerting extra pressure of the brain tissues, resulting in an increased intracranial pressure.

The early onset symptoms of increased intracranial pressure include regular morning headaches, vomiting, lethargy, etc. If untreated, these symptoms can spiral down to persistent vomiting, ophthalmoplegia, Cushing’s triad of bradycardia, irregular respiration, and systolic hypertension, coma, and even death in certain extreme cases. Hence, timely intervention with the help of intracranial pressure monitoring devices is extremely necessary.

Types of Intracranial Pressure Monitoring Devices

Intracranial pressure can be measured in two ways- invasive or non-invasive techniques. Invasive techniques, as the name suggests, include inserting certain intracranial pressure monitoring devices inside the skull, while non-invasive techniques refer to monitoring intracranial pressure without inserting any device. Some methods of both these types are given below:

1. External Ventricular Drainage (Invasive)

External ventricular drainage is generally considered to be the gold standard as far as intracranial pressure monitoring is considered. It is an invasive technique wherein a catheter is inserted through a burr hole into one of the ventricles in order to measure the volume of the cerebrospinal fluid and note the pressure exerted by it on the brain tissues. The catheter apart from acting as an intracranial pressure monitoring device, can also be used for draining out the excess cerebrospinal fluid, and also for administering the necessary antibiotics for treatment of the brain tissues. Thus, despite certain risks associated, this technique is the most used of all other methods for treating disorders arising out of elevated intracranial pressures.

2. Mircrotransducer Intracranial Pressure Monitoring Devices (Invasive)

These intracranial pressure monitoring devices include inserting of fiber optic devices, strain gauge devices, or pneumatic sensors inside the skull. Of these, fiber optic devices monitor the rise in the levels of cerebrospinal fluid with the help of light and mirrors. On the other hand, strain gauge devices employ sensors and piezoelectric strain gauges to check the changes in the pressure. Pneumatic sensors use balloon catheter to monitor the pressure levels inside the skull.

3. Transcranial Doppler Ultrasonography (TCD) (Non-invasive)

This technique involves using intracranial pressure monitoring devices that work on the principle of ultrasound. These devices are used to measure the velocity of the blood flow in the middle cerebral artery by sending soundwaves through the tissues of the skull and interpreting the condition inside the skull based on the speed and direction of the released sound waves. This technique is used to detect several medical conditions like acute ischemic stroke, vasospasm, etc.

4. Optic Nerve Sheath Diameter (Non-invasive)

Optic nerve is one of the most important components of the central nervous system. In order to protect such an important nerve, it is naturally provided with a dural sheath which is connected to the subarachnoid space surrounding the brain tissues. In case of an increased intracranial pressure level, the dural sheath expands which can be detected by an intracranial pressure monitoring device using transocular ultrasound. The most important advantage of this technique is that it is cheap and efficient as compared to other non-invasive methods.

The Bottom Line

The intracranial pressure monitoring devices market is poised to grow hugely due to the massive scale of research and development that is underway in the medical world. Apart from the techniques mentioned above, several other methods have been developed such as Tympanic Membrane Displacement (TMD), Magnetic Resonance Imaging (MRI) & Computer Tomography (CT), Fundoscopy, etc. Both invasive and non-invasive techniques come with their pros and cons but with enough research, the risk levels associated with these techniques have been substantially brought down.

About the Author(s)

Akhilesh Prabhugaonkar

Akhilesh Prabhugaonkar holds a bachelor’s degree in Electronics Engineering from the reputed Vishwakarma Institute of Technology. He has a special interest in the field of forensics, world history, international relations and foreign policy, sports, agriculture, astronomy, security and oceanography. An ardent bibliophile and melophile, Akhilesh loves to write on topics of his interest and various other societal issues. This love for writing made him enter the professional world of content writing and pursue his career in this direction.