What are the three elements described in the Monro-Kellie doctrine?

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.

What is the normal range for intracranial pressure?

In the horizontal position, the normal ICP in healthy adult subjects was reported to be within the range of 7–15 mm Hg. In the vertical position it is negative with a mean of around −10 mm Hg, but not exceeding −15 mm Hg. The definition of raised ICP depends on the specific pathology.

What are the four stages of increased intracranial pressure?

Intracranial hypertension is classified in four forms based on the etiopathogenesis: parenchymatous intracranial hypertension with an intrinsic cerebral cause, vascular intracranial hypertension, which has its etiology in disorders of the cerebral blood circulation, meningeal intracranial hypertension and idiopathic …

Which positions is used to help reduce intracranial pressure ICP?

In most patients with intracranial hypertension, head and trunk elevation up to 30 degrees is useful in helping to decrease ICP, providing that a safe CPP of at least 70 mmHg or even 80 mmHg is maintained. Patients in poor haemodynamic conditions are best nursed flat.

Why is Monro-Kellie hypothesis important?

The Monro-Kellie doctrine or hypothesis states that the sum of volumes of brain, cerebrospinal fluid (CSF) and intracerebral blood is constant. The doctrine is fundamental to our understanding of the negative effect of raised intracranial pressure on the brain.

What is the clinical significance of CPP?

It is the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP), measured in millimeters of mercury (mm Hg). Maintaining appropriate CPP is critical in managing patients with intracranial pathology, including traumatic brain injury, and with hemodynamic distress, such as shock.

What does high CPP mean?

Is a high CPP harmful? If the BP becomes elevated, the increased CPP can lead to increased cerebral blood flow. When combined with increased capillary permeability or cerebral vasodilation, blood flow can increase to the point where brain edema worsens.

What is an early indicator of increased intracranial pressure?

Pupillary reactivity as an early indicator of increased intracranial pressure: The introduction of the Neurological Pupil index.

What is an early indicator of increasing intracranial pressure?

What is Cushing’s response?

The Cushing reflex (vasopressor response, Cushing reaction, Cushing effect, and Cushing phenomenon) is a physiological nervous system response to acute elevations of intracranial pressure (ICP), resulting in Cushing’s triad of widened pulse pressure (increasing systolic, decreasing diastolic), bradycardia, and …

Does Reverse Trendelenburg lower ICP?

Intracranial pressure after RTP resulted in decreased tension of the dura. RTP appears to be an effective means of reducing ICP during craniotomy, thereby reducing the risk of cerebral herniation.

What position increases ICP?

However, ICP is generally significantly higher when the patient is in the horizontal position. This study was undertaken to clarify the issue of optimal head position in the care of head-injured patients.

What are the implications of Monro Kellie hypothesis?

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 Monro-Kellie doctrine?

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 is Monro Kelly’s theory of brain function?

MONRO – KELLIE DOCTRINE. Conversely, a loss of brain volume results in an increase in blood and CSF to maintain a constant intracranial pressure. The ramifications of this theory have dramatic implications in clinical practice today: small changes in brain volume (bleed or tumor, etc.) can be compensated for, despite a solid encasing skull.

Who was George Kellie and what did he do?

1824 – George Kellie was an Edinburgh based surgeon and former student of Monro. His contribution to the doctrine stems from papers he published on the post mortem examination of two individuals that were found deceased in Leith the morning after a winter storm.