พญ.อิศราภรณ์ พูน สวัสดิ ์ พบ.

A I T S A R A P O R N P H U N S AWA T M D .

D E PA R T M E N T O F A N E S T H E S I O L O G Y, FA C U L T Y O F M E D I C I N E N A R E S A U N U N I V E R S I T Y H O S P I T A L

Anatomy of the cranium

 Cranium is a rigid box containing 1. brain 80% (1300 ml) 2. blood 12% (110 ml) 3. CSF 8% (65 ml) All of these contents are maintained a balanced pressure referred to as intracranial pressure (ICP)

Intracranial pressure

The normal range for ICP varies with age Age group ICP normal (mmHg) Infant Child

Adult

< 7.5

< 10

< 15 (7.5 -20 cm H2O)

Best Practice & Research Clinical Anaesthesiology.2007;21: 517–38

Intracranial pressure

 Transient elevation with straining, coughing, or trendelenberg position  Sustained ICP ≥20 : abnormal  ICP 20-40mmHg : moderate ICH (intracranial hypertension)  Sustained ICP ≥ 40 mm Hg threatening ICH indicate Goal: Keep ICP≤ 20 mmHg severe , life Neurol Clin 2008;26: 521–41

Monro-Kellie Doctrine (Compensatory mechanism)

 The skull is a rigid bowl that offers little flexibility for changes in the size of the three intracranial components.

other two.

To maintain normal pressure in the skull, any increase in the size of one component initially will lead to a compensatory decrease in one or both of the

Brain

 displaced to moderate degrees to accommodate an expanding mass.

 Slow expansion  Rapid expansion

Cerebral herniation

1.Subfalcine 2.Uncal transtentorial 3.Tonsillar

4.Trancalvarial

5.Transtentorial(Central) 6.Upward transtentorial

Adverse effect of ICH

 Decreased CPP  Brain ishemia  Brain herniation brain edema increase ICP

Conditions Associated with Increased ICP

Intracranial mass lesions Increased brain volume (cytotoxic edema)

 Subdural hematoma  Epidural hematoma  Brain tumor  Cerebral abscess  Intracerebral hemorrhage  Cerebral infarction  Global hypoxia-ischemia  Reye's syndrome  Acute hyponatremia

Conditions Associated with Increased ICP

        

Increased blood and brain volume (vasogenic edema)

Hepatic encephalopathy Traumatic brain injury Meningitis Encephalitis Hypertensive encephalopathy Eclampsia Subarachnoid hemorrhage Dural sinus thrombosis Altitude-related cerebral edema

Increased CSF volume

   Communicating hydrocephalus Noncommunicating hydrocephalus Choroid plexus papilloma

Extracranial cause

(

secondary

) Prevent cause, Prevent ICH

Clinical Signs of Increased ICP

Clinical Signs of Increased ICP

  Signs which are almost always present    Depressed level of consciousness (lethargy, stupor, coma) Hypertension, with or without bradycardia Cushing triad: hypertension, bradycardia, and respiratory depression Symptoms and signs which are sometimes present     Headache Vomiting Papilledema Sixth cranial nerve palsies

Neurogenic Patterns of Respiration

Type

Cheynes - Stokes Respiration

location

Diffuse forebrain injury Midbrain ,such as thalamus Central neurogenic hyperventilation Apneustic ( pause at full inspiration ) Ataxic ( radom deep and shallow breaths ) Cluster ( irregular breaths and pause ) Mid to caudal pontine, brainstem or Basilar a. occlusion Medulla lesion (terminal stage) Lower medulla

Powerpoint Templates

 Monitoring Clinical Status

2. Pupillary examination; 3. Ocular motor examination (with special attention to the third and sixth cranial nerves); 4. Motor examination with special attention for hemiparesis; 5. Presence of nausea or vomiting; 6. Complaints of headache; and 7. Current vital signs and the recent course.

Powerpoint Templates Page 16

  CT-brain MRI Powerpoint Templates Page 17

Powerpoint Templates Page 18

  ◦ Measure basal arterial cerebral blood flow, 40 to 70 cm/s.

Diffuse Increase ICP arteries compress cerebral increase flow velocity 

TCD is insufficiently sensitive and specific to provide a noninvasive alternative to ICP monitoring.

Powerpoint Templates Page 19

1

.

Fontanometry 2

.

Epidural pressure monitoring 3

.

Subdural pressure monitoring 4

.

Parenchymal measuring 5

.

Ventricular pressure monitoring 6.

Lumbar pressure monitoring Powerpoint Templates – 41 Page 20

Direct ICP Monitoring

Powerpoint Templates Page 21

    (1) the condition leading to ICP elevation is amenable to treatment (2) ongoing direct assessment of ICP will be of consequence in decisions regarding treatment interventions (3) the risks of device placement do not outweigh the potential benefits.

Powerpoint Templates 41 Page 22

Treatment of increased ICP

CPP=MAP-ICP CBF = CPP / CVR The goals of ICP treatment 1. Maintain ICP ≤ 20-25 mmHg.

2.Maintain CPP ≥ 60 MAP.

mmHg by maintaining adequate 3. Avoid factors that aggravate or precipitate elevated ICP.

Neurol Clin 2008;26: 521–41

Management of



ICP

 Head elevation 15 ˚ - 30 ˚  Hyperventilation  Control BP  Hyperosmolar therapy  Sedative and paralysis  Steroid  Decompressive craniectomy and lumbar drainage

Head elevation

 venous out flow resistance  CSF from intracranial spinal compartment  Position above heart and prevent kinking or compression of jugular v.(c-spine precaution) The mean ICP was significantly lower when the patient's head was elevated at 30° than at 0° ( 14.1 ± 6.7 mm Hg vs . 19.7 ± 8.3 mm Hg ).

J Neurosurg 1992;76:207–11 .

Head elevation

 The anesthetized or hypovolemic pts may response to head elevation by developing systemic hypotension  Must treat to avoid adverse impact to CPP Neurol Clin 2008;26: 521–41

Oxygenation and Ventilation

 Respiratory dysfunction is common esp in head trauma.  Hypoxia and hypercapnia can ICP  Adequate ventilation: Pao2 ≥60 mmHg Paco2:30-35 mmHg Neurol Clin 2008;26: 521–41

Oxygenation and Ventilation

PEEP    intrathoracic pressure are transmitted directly through the neck to the intracranial cavity

Increase intrathoracic pressure: increase ICP

decreased venous return to the right atrium and a rise in jugular venous pressure ,

increase in CBV and in ICP

Decreased venous return also leads to a drop in cardiac output and blood pressure , thereby reducing CPP

Oxygenation and Ventilation

 The consequences of PEEP on ICP depend on  lung compliance ,  ICP  MAP

Minimal consequences for ICP are usually observed when lung compliance is low

J Trauma 2005;58:571–6.

Hypercapnia and hypocapnia

  Hypercapnia   Cerebral vasodilate  PaCO 2  1 mmHg  CBF and ICP CBF 2 ml/100g/min In situations of reduced intracranial compliance  Increased ICP and reduced CPP  In situations of reduced cerebral blood flow and oxygen delivery , where ICH is not a problem  improvements in cerebral blood flow

Hyperventilation

   Hyperventilation PaCO2, which can induce constriction cerebral arteries    Cerebral vasodilate PaCO 2 1 mmHg   PaCO 2 1 mmHg  CBF and ICP CBF 2 ml/100g/min of CBV 0.04 ml/100g/min Aim: Paco 2 30-35 mmHg Hyperventilation may produce a decrease in CBF su ffi cient to induce ischemia.



Hyperventilation should be avoided during the first 24 hours after injury when cerebral blood flow

(

CBF

)

is often critically reduced.

Neurol Clin 2008;26: 521–41

Hyperventilation

  Most e ff ective use of hyperventilation is acutely The vasoconstrictive e ff ect : 11-20 hours  When hypocarbia is induced and maintained for several hours, it should be reversed slowly , over several days, to minimize this rebound hyperemia Prophylactic hyperventilation ( PaCO 2 of 25 mm Hg or less ) is not recommended .

Crit Care Clin 1997;13:163–84.

Decompressive Abd Pressure

 intra-abdominal P.(abdominal compartment syndrome), can ICP by obstructing cerebral venous outflow.

 Immediate reductions in ICP with decompressive laparotomy Neurol Clin 2008;26: 521–41

Decompressive Abdominal Pressure

 17 pts with intractable ICH that is refractory to medical treatment (abdominal compartment syndrome is not present)  abdominal fascial release can e ff ectively (30.0

± 4.0 17.5

± 3.2) reduce ICP J Trauma 2004;57:687–93 .

Hyperthermia

 metabolic rate 10-13% vasodilator . per 1 ° C and is a potent  Induce dilation of cerebral vessels can CBF and ICP.

 Fever during the post injury period worsens neurologic injury in TBI Neurosurgery 1996;38:533–41

Hypothermia

  Prophylactic hypothermia  Not significantly associated with decrease mortality when compare with normothermic controle Cochrane review in 2004  not find any evidence supporting the use of hypothermia during the treatment of TBI ,  a statistically significant increased risk of pneumonia and other potentially harmful side effects

indicated at present,hypothermia may be an effective adjunctive treatment of increased ICP refractory to other medical management

Hypertension

 Common in pts who have ICH  Esp 2 ° to HI  Characterize by a SBP increase greater than diastolic increase.  Associate with sympathetic hyperactivity Neurosurgery 1996;38:533–41 .

Hypertension

 Not reduce BP in HT pts associated with untreated intracranial mass lesions  cerebral perfusion maintain by the higher BP.  In the absence of an intracranial mass controversy to treat HT lesion, Neurol Clin 2008;26:521–41

Hypertension

 When autoregulation is impaired , common after TBI,  HT may CBF and ICP ,cerebral edema ,risk for post-op intracranial hemorrhage 

Keep SBP 120-150 mmHg

Neurol Clin 2008;26:521–41

Hypertension

 Vasodilating drugs e.g. nitroprusside, NTG , and nifedipine , can ICP and catecholamines  Sympathomimetic-blocking antiHT drugs,  β -blocking drugs ( esmolol)  α -central acting receptor agonists (clonidine) are preferred ( reduce BP without a ff ecting the ICP )  Agents with a short half-life have an advantage when BP is labile.

Neurol Clin 2008;26:521–41

Treatment of anemia

 Mechanism: CBF delivery for maintain cerebral when severe anemia. oxygen  Anemia has not been clearly shown to exacerbate ICP after TBI,  a common practice is to maintain Hb ≥ 10 g/dL. Neurol Clin 2008;26:521–41

Prevention of seizures

 Seizure occur 15-20% in severe HI.  Seizures can CMR and ICP  In severe TBI, 50% of seizures may be monitoring subclinical and can be detected only with continuous EEG J Neurosurg 1999;91:750–60

Prevention of seizures

 Significant risk factors for later seizures - brain contusion - subdural hematoma - depressed skull fracture - penetrating head wound - loss of consciousness or amnesia ≥1 day - age ≥ 65 years Neurol Clin 2008;26:521–41

Barbiturates

   High dose

barbiturate

administration is recommended to control elevated ICP refractory to maximum standard medical and surgical treatment.

 Dose-dependent CBF and CMRO2  ICP by CBF and CBV  Neuroprotective effect Hemodynamic stability is essential before and during barbiturate therapy.

Barbiturate coma: EEG shows a burst suppression pattern.

Barbiturate coma

 Complications coma include hypotension during treatment with barbiturate in 58%of patients hypokalemia in 82% respiratory complications infections in 55% in 76% hepatic dysfunction renal dysfunction in 87% in 47% Acta Neurochir 1992;117:153–9

Propofol

 recommended for the control of ICP , but not for improvement in mortality or 6 month outcome.

High dose propofol



Hypotension and propofol infusion syndrome

Propofol infusion syndrome

Acute refractory bradycardia leading to asystole , in the presence of one or more of the following : 

metabolic acidosis (base deficit > 10 mmol/l),



rhabdomyolysis ,



hyperlipidaemia ,



enlarged or fatty liver.

propofol infusions at doses higher than 4 mg/kg/h for greater than 48 h duration

HYPEROSMOLAR THERAPY

Mannitol

 onset 1-5 min  peak e ff ect 20-60 min  Duration 1.5-6 hrs depending on the clinical condition  Dose:Bolus 0.25-1 g/kg  Urgent reduce ICP :initial dose of 1 g/kg  Can be repeated 0.25 - 0.5 g/kg q 2-6 hrs. Neurol Clin 2008;26:521–41

Mannitol

 Sosm optimal is 300-320 mOsm and should ≤ 320 mOsm to avoid S/E e.g. hypovolemia, hyperosmolarity, and renal failure.

 Attention to replacing fluid that is lost because of mannitol-induced diuresis, or intravascular volume depletion Neurol Clin 2008;26:521–41

Mannitol

 Osmotic e ff ect of mannitol serum tonicity edema fluid from cerebral parenchyma) ( draws Neurol Clin 2008;26:521–41

Mannitol

 Mannitol has rheologic ( Hct and blood viscosity ( o 2 delivery to the brain)   CSF production, lead to prolonged ICP free radical scavenging e ff ects.

Neurol Clin 2008;26:521–41

Loop diuretic

Furosemide  Dose: 0.5-1 mg/kg  Synergize with mannitol  Greater ICP, less brain edema, prolong elevation of plasma osmolarity  Effect from CSF formation across choroid plexus via alter Na + transport

Hypertonic saline

 Concentration 3-29.2%,

Hypertonic saline

      Osmotic force to draw water from the interstitial space brain parenchyma into the intravascular compartment in the presence of an intact BBB of the intracranial volume and ICP.

augments volume resuscitation circulating BV , MAP,and CPP modulation of the inflammatory response by adhesion of leukocytes to endothelium Effective to reduce refractory increased ICP Anesth Analg 2006;102:1836–46

Hypertonic saline

  Adverse e ff ects - hematologic and E’lyte abnormalities HypoNa + should be excluded before administering HTS, to reduce the risk for central pontine myelinolysis J Trauma 2001;50:367–83    Serum Na is maintained 145-155 mmol/L in TBI. repeated until ICP is controlled or Na 155 mmol/L After 3–4 days of HTS therapy, boluses of furosemide to mobilize tissue Na.

Anesth Analg 2006;102:1836–46

Steroids

    Common use for 1 ° and metastatic brain tumors Decrease vasogenic cerebral edema . ICH decreases in 2-5 days The most commonly used regimen Dexamethasone 4 mg q 6 hours IV.

 Other neurosurgical disorders, such as TBI or spontaneous ICH - not have a benefit Curr Opin Oncol2004;16:593–600

CSF drainage

    Decrease ICP immediately by reducing intracranial volume If brain is di ff use swollen, the ventricles may collapse, limited usefulness Special consideration - large hemispheric mass - infratentorial mass Result in subfalcine herniation, upward trantentorial herniation Neurol Clin 2008;26: 521–41

Surgical interventions

 Resection of mass lesions  Decompressive craniectomy Failure of medical therapy Persistent cerebral swelling or increase ICP Prevent transtentorial herniation Anesthesiology Clin 2007;25: 579-603

Prevent secondary brain damaged

 Avoid hyper or hypoglycemia  Maintain glucose level 90-150 mg/dL  A relative reduction in mortality of around 30% in patients with severe HI after the introduction of protocol  Correct electrolyte imbalance  Infection control  Prevent other organs dysfunction