浙江大学医学院：《神经外科学 Neurosurgery》颅内压增高 increased intracranial pressure（INTRACRANIAL DYNAMICS）

浙医一院 Neurosurgery

Neurosurgery

浙医一院 INTRACRANIAL DYNAMICS

INTRACRANIAL DYNAMICS

浙医 Fhe first principle is obvious: the cranial cavity has a fixed volume that is filled by various Ings 1. Brain tissue 2. CSF 3. Blood vessels and intravascular blood volume 4. Volume associated with any pathologic process which can include tumor, cyst, abscess hemorrhage, edema, necrosis

The first principle is obvious: the cranial cavity has a fixed volume that is filled by various things: 1. Brain tissue 2. CSF 3. Blood vessels and intravascular blood volume 4. Volume associated with any pathologic process, which can include tumor, cyst, abscess, hemorrhage, edema, necrosis

dhE- A consequence of this principle: If there is an elevation in the volume of any one compartment there is a stage of compensation in which the volume of one or more other compartments can be reduced to avoid elevations in Icp

A consequence of this principle: If there is an elevation in the volume of any one compartment, there is a stage of compensation in which the volume of one or more other compartments can be reduced to avoid elevations in ICP

QUESTION: What is Intracranial Pressure(ICP)? >CP: the pressure produced by the content of the cranial cavity(brain tissue, CSF and blood) on the cranial cavity wall >Normal cp: Adu|t:0.7~2.0kPa(70~200mH20)。 chi|d:0.5~1.0kPa(50~100mH20)

QUESTION: What is Intracranial Pressure (ICP)? ➢ICP：the pressure produced by the content of the cranial cavity (brain tissue, CSF and blood) on the cranial cavity wall. ➢Normal ICP： Adult：0.7～2.0 kPa（70～200mmH2O）。 Child：0.5～1.0kPa（50～100mmH2O）

The second principle is not 浙医一院 obvious and may seem counterintuitive The spinal fluid is produced at a constant rate(15-20 mL/hr) largely by the choroid plexus of the ventricles by an energy- dependent, physicochemical pI rocess

The second principle is not obvious and may seem counterintuitive: The spinal fluid is produced at a constant rate (∼15-20 mL/hr) largely by the choroid plexus of the ventricles by an energy￾dependent, physicochemical process

浙一 The third basic principle. The cerebral blood flow(CBF) normally varies over a wide range (30-100 mL per 100g brain tissue per minute), depending on metabolic demand from neuronal activity within a particular area of the brain

The third basic principle: The cerebral blood flow (CBF) normally varies over a wide range (30-100 mL per 100 g brain tissue per minute), depending on metabolic demand from neuronal activity within a particular area of the brain

浙医一院 For any brain region CBF=Cerebral perfusion pressure/ Cerebral vascular resistance

For any brain region CBF=Cerebral perfusion pressure/ Cerebral vascular resistance

浙医一院 The fourth principle Injured tissue swells, making obvious the potential for a cascading injury by a vicious cycle. If the stage of compensation mentioned earlier, even with therapy, is exceeded and ICP is elevated high enough by whatever mechanism so that cerebral perfusion pressure(CPP) declines. cbf can decline to levels where tissue InJury occurs

The fourth principle: Injured tissue swells, making obvious the potential for a cascading injury by a vicious cycle. If the stage of compensation mentioned earlier, even with therapy, is exceeded and ICP is elevated high enough by whatever mechanism so that cerebral perfusion pressure (CPP) declines, CBF can decline to levels where tissue injury occurs

The vicious cycle. CPP. cerebral perfusion 浙医一院 pressure; ICP, intracranial pressure ICP CPP Infarction Edema

Edema Infarction ICP CPP The vicious cycle. CPP, cerebral perfusion pressure; ICP, intracranial pressure