The document discusses cerebrospinal fluid (CSF) physiology, circulation, and its role in protecting the brain, providing nutrients, and removing waste. It details the formation and composition of CSF, factors affecting its production, and the regulation of intracranial pressure, along with methods for measurement and treatment of conditions like hydrocephalus. Anesthesia management considerations in patients with increased ICP are also outlined, emphasizing careful monitoring and specific drug protocols.

1. CSF PHYSIOLOGY AND
CIRCULATION
Presenter : Dr Rakshitha R
Moderator : Dr Lakshmi

2. INTRODUCTION
 Cerebrospinal fluid is a clear fluid
present in the ventricles of the brain,
the central canal of the spinal cord
and the subarachnoid space.

3. Function of CSF
 Protects, lubricates the brain.
 Provides nutrients
 Removes waste.
 Transport medium for nutrients and
metabolites, endocrine substances and
neurotransmitters.
 Biomarker for disease diagnosis.
 Contains growth factor and micro RNA
for neurogenesis.
 Blood-CSF barrier

5. FORMATION OF CSF
 3 sites :
Choroid plexus (50-70%)
Ependymal surfaces of ventricles
Perivascular spaces.

6.  Formed at rate of : 500-600ml/day OR
: 0.35-0.40ml/min
• Turn over time : 5-7hours = 4
times/day
• CSF volume : 150ml (125ml in cranial
and subarachnoid spaces+ 25ml in
ventricle)

7. CSF PRESSURE
(mm Hg)
CHILDREN 3.0-7.5
ADULTS 4.5-13.5
CSF VOLUME (ml)
INFANTS 40-60
YOUNG CHILDREN 60-100
OLDER CHILDREN 80-120
ADULTS 100-160

8. Choroid plexus
 It is a cauliflower like growth of blood
vessels covered by a thin layer of
epithelial cells.
 It projects into temporal horn of lateral
ventricle, posterior part of 3rd ventricle
and roof of 4th ventricle.

9. Nerve supply: branches of vagus and
glossopharyngeal nerve and sympathetic
nerves.
Blood supply:
Body of lateral ventricle Posterior choroidal artery
Body of third ventricle Anterior choroidal artery
Temporal horns Superior cerebellar artery
Fourth ventricle Posterior inferior cerebellar
artery.

11. Formation of CSF at choroid
plexus
 Filteration of plasma across choroidal
capillary endothelium into interstitial
compartment according to pressure
gradient.
 Secretion of ions and water across
epithelial cells.

13. CIRCULATION OF CSF

15. ABSORPTION OF CSF
• All CSF formed is reabsorbed into the
venous circulation through arachnoid
villi or granulations.
• These villi project the subarachnoid
spaces into the venous sinuses of the
brain and occasionally into the venous
of the spinal cord.

17. EFFECT OF DRUGS ON CSF
FORMATION

18. Desfluran
e
Enflurane Halothane Isoflurane Sevofluran
e
Nitrous
Oxide
secretion + + -- 0 -- 0
absorptio
n
0 -- -- + -- 0
Ketamine Etomidate Propofol Pentobarbital Thiopental
secretion 0 -- 0 0 0
absorption -- + 0 0 --
Midazolam Flumzenil Fentanyl Sufentanyl Lidocaine
secretion 0 0 0 0 --
absorption -- 0 + + 0
INHALED ANESTHETICS
IV ANESTHETICS
OTHER IV ANESTHETICS

19. OTHER DRUGS :
 Acetazolamide inhibit carbonic
anhydrase enzyme,constricts arterioles
=> decrease CSF formation.
 Furosemide inhibit sodium chloride
transport => decrease CSF formation.
 Theophyllin is a phosphodiesterase
inhibitor -increase CAMP- stimulate
sodium potassium pump => increase
CSF production.

20.  Digoxin inhibit sodium potassium
ATPase pump=> decrease CSF
formation.
 Vasopressin constrict choroid plexus
blood vessel => decrease CSF
production.
 Muscle relaxant has no effect on CSF
formation.
 Dexamethasone inhibit sodium
potassium ATPase => decrease CSF
production.

21.  Alpha agonist causes vasoconstriction
=> decrease CSF formation.
 Cholinergic drugs acts on muscarinic
receptor on choroid epithelium =>
decrease CSF formation.
 Hypothermia (1˚C)decrease cerebral
blood flow => decrease CSF
formation. (11%)
 Hypocapnia decrease cerebral blood
flow => decrease CSF production
 Metabolic alkalosis decrease
formation of CSF.

22. Composition of CSF

25. Intracranial Pressure(ICP)
 The intracranial and spinal vault
contains neural tissue, blood and CSF
and is enclosed by duramater and
bone.
 The pressure within this space –
intracranial pressure.
 Normal ICP is <15mm Hg.
 This pressure is regulated by rate of
formation of CSF and resistance to
CSF reabsorption by arachnoid villi.

26. Monro Kellie Doctrine
 The sum of volumes of brain, CSF and
intracranial blood is constant.
 An increase in volume of one component will
be compensated by decrease in one or both
of the remaining two.

30. Causes of increase ICP
Physiological causes:
 Coughing
 Sneezing
 Straining

33. Signs and symptoms
 Headache
 Nausea
 Vomiting
 Papilledema

34. Methods to measure ICP
 Pressure transducers can be placed
under aseptic conditions into subdural
space (subdural bolt), brain
parenchyma or ventricle
(ventriculostomy)
 Lumbar arachnoid catheter.

35. Methods to decrease ICP
 Elevation of the head.
 Hyperventilation.
 CSF drainage.
 Hyperosmotic drugs.
 Diuretics.
 Corticosteroids.
 Vasoconstricting anesthetics –
barbiturates, propofol.
 Surgical decompression.

36. Hydrocephalus
 One of the most common pediatric and
adult neurosurgical disorder,
 An abnormal increase in amount of CSF
resulting from a disturbance of formation,
flow or absorption of CSF thus resulting in
enlarged cerebral ventricles.

38. Clinical presentation :
In infants and newborn :
 Cranium enlarges>facial growth
 Irritable, lethargy
 Delayed milestones
 Vomiting
 Decrease oral intake
 Macewen’s sign- cracked pot sound
on percussion over dilated ventricle
 Hyperactive reflexes

40. Older child/adults:
Symptoms of increased ICP-
 Headache
 Papilledema
 Nausea, vomiting
 Upward gaze
 Abducens palsy

41. Treatment :
Medical therapy –
 Acetazolamide :25mg/kg/day PO
divided TID increase by 25mg/kg/day
until 100mg/kg/day.
 Furosemide : 1mg/kg/day PO divided
TID
 Correct electrolyte abnormalities

42. Neurosurgical procedures –
 Ventriculostomy
 Choroid plexectomy
 Shunting – ventriculoperitoneal shunt
- ventriculoatrial shunt
- ventriculopleural shunt
- lumboperitoneal shunt
- torkildsen shunt

43. Anesthesia management
 History taking and physical examination
– severity of ICP and neurological status.
 Premedication : avoid sedation.If
required titrated dose of oral/intranasal
midazolam may be used..
 Prophylactic antibiotics should be given
to lower shunt infection rate.
 Monitoring : pulse oximetry, ECG, blood
pressure, capnometry, temperature
 Patient head is placed 30˚head up
position.

44.  Induction : high ICP and vomiting increase
risk of aspiration. So rapid sequence
induction with thiopentone (3-5mg/kg) or
propofol (2-4mg/kg) followed by
succinylcholine or rocuronium is used.
 Institute hyperventilation.(PaCO2 of 25-30
mm Hg).
 Avoid spontaneous ventilation in
ventriculopleural shunt ( to prevent
pneumothorax) and ventriculoatrial shunt (
to prevent air embolism).
 Maintainance: air, oxygen, isoflurane/
sevoflurane, fentanyl, paracetamol,
intermediate acting non depolarising
muscle relaxants.

45.  Replace loss of intravascular volume
due to emesis or diuresis with saline.
 Maintain normothermia.
 Extubate when fully awake.
 Post operatively patient should be
nursed flat so as to avoid subdural
hemorrhage which may occur
because of rapid collpse of ventricles
in head high position. Monitor mental
status as reobstruction can occur.

46. References
 Guyton and Hall Textbook Of Medical
Physiology.
 Stoelting’s Pharmacology and
Physiology in Anesthetic Practice.
 Stoelting’s Anesthesia Co-Existing
Diseaase.

47. THANK YOU