What is the Monro-Kellie theory?
What is the Monro-Kellie theory?
What finally came to be known as the Monro–Kellie doctrine, or hypothesis, is that the sum of volumes of brain, CSF, and intracranial blood is constant. An increase in one should cause a decrease in one or both of the remaining two.
What are the three elements described in the Monro-Kellie doctrine?
The Monro-Kellie doctrine states that the skull is a rigid compartment and contains three components: brain, blood, and cerebrospinal fluid. If an increase occurs in the volume of one component, the volume of one or more other components must decrease, or ICP will be elevated.
How does the Monro-Kellie hypothesis maintain normal ICP?
According to traditional pressure–volume relationships outlined in 1783 by Monro and Kellie1,8, as ICP increases, vascular blood and CSF are displaced as part of a dynamic equilibrium to help maintain normal pressure within the inelastic cranium, while brain tissue remains unchanged.
Why is the Monro-Kellie hypothesis important?
This hypothesis has substantial theoretical implications in increased intracranial pressure and in decreased CSF volume. Many of the MRI abnormalities seen in intracranial hypotension or CSF volume depletion can be explained by the Monro-Kellie hypothesis.
What is the formula for calculating CPP?
In addition, using arterial pressure (AP), the cerebral perfusion pressure (CPP) can be calculated (CPP = AP-ICP). CPP is important in considering extracranial factors, such as changes in blood volume or arterial pressure, resulting in secondary brain swelling and ischemia.
How is ICP calculated?
The most common and most accurate method is with an intraventricular monitor. As such, intraventricular measurement of ICP is the current gold standard. [2] An intraventricular catheter is inserted into a hole drilled into the skull and then into the lateral ventricle to directly measure the pressure of the CSF.
Why is Monro-Kellie hypothesis important?
How is CPP 2021 calculated?
Manual calculation for CPP
- Step 1: Calculate the basic pay-period exemption.
- Step 2: Calculate the total pensionable income.
- Step 3: Deduct the basic pay-period exemption from the total pensionable income.
- Step 4: Calculate the amount of CPP contributions.
- Step 5: Calculate the amount of CPP contributions you have to pay.
What is the MAP equation?
A common method used to estimate the MAP is the following formula: MAP = DP + 1/3(SP – DP) or MAP = DP + 1/3(PP)