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Anesthesia Principles III
Management of the head injured patient
82
Medical
Graduate
07/16/2010

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Cards

Term
What age group has the highest incidence of head injuries?
Definition
*Young people age <35
Term
What is the second highest most common age group for Head injuries?
Definition
*Elderly
Term
The ratio of occurrence of head injury men: women is....
Definition
2:1
Term
What are common etiologies of head injuries?
Definition

*Falls

*Motor vehicle accidents (leading cause of HI in young)

*Struck by/against

*Assaults

 

Term
How often is ETOH involved in head injury?
Definition
*50% of cases
Term
What four terms are used to classify head injury?
Definition

*Penetrating vs. closed

*Primary vs. Secondary

Term
When does primary head injury occur?
Definition
*at the time of insult
Term
How does damage occur in primary head injury?
Definition

*Results directly from the disruption of intracranial structures

*Due to the biomechanical forces applied to the cranium and brain

Term
What are some common causes of primary head injury?
Definition

*Concussion

*Fracture

*Hematoma

*Contusion

Term
How does secondary head injury result?
Definition

*Injury resulting from the initial trauma

*Secondary deterioration

Term
List some secondary head injury contributing factors:
Definition

*Hypoxia

*Hypercarbia

*Hypotension

*Intracranial HTN

*Ischemia

*Hyperglycemia

*Vasospasm

*Anemia

*Acidosis

*Extreme Hypocarbia

*Seizures

*Hyperthermia

Term
What five factors have been associated with poor outcome in relation to head injury?
Definition

*60 years of age or more

*Initial GCS of <5

*A fixed, dilated pupil

*Prolonged hypotension or hypoxia

*Presence of a mass lesion requiring operative intervention

Term
What are the most important factors that contribute to Morbidity and mortality?
Definition

*Hypoxemia PaO2 <60

*Hypotension SBP <90

*70% of hypotensive pts have significant M&M

*90% with both have significant M&M

Term
What information should be ascertained in a neurologic assessment after an injury?
Definition

*History

*Type of injury

*Course of events since injury

*Any seizure, LOC, apnea?

*Signs of increased ICP

*Any known medical history

*Think AMPLE

Allergies

Meds

Past illness

Last meal

Events related to injury (what happened?)

Term
What scale is used to measure neurological status?
Definition
*Glascow coma scale
Term
What are the 3 elements of the GCS and what is the top and lowest scores possible?
Definition

*Best eye opening (4)

*Best verbal response (5)

*Best motor response (6)

*3 is lowest

*15 is highest

Term
How can pupillary changes be used?
Definition
*Pupillary changes are useful predictors of outcome
Term
Bilateral dilated pupils on admit predict....
Definition
*90% mortality
Term
Bilateral constricted pupils on admit predict....
Definition
*66% mortality
Term
Normal pupils on admit indicate.....
Definition
*20% mortality
Term
What presentation of vital signs are expected with head injury?
Definition

*Hypotension 

*HTN and Bradycardia

*Hpotension and Bradycardia (think spine injury)

Term
What neurologic exams should be measured first?
Definition

*LOC and mental status first

*Cranial nerve exam to assess brainstem

Term
What type of movement is seen if the injury is at the cortical level?
Definition

*Decorticate movement

*Flexion of UEs and hyperextension of the LE

Term
When injury extends to the midbrain what type of posturing occurs?
Definition

*Decerebrate posture 

*Hyperextension of both the UE and LE

Term
When injury involves the pons what occurs?
Definition
*Flaccidity
Term
What is the goal of initial management of the head injured patient?
Definition
*Minimize the occurrence of secondary injury
Term
How is secondary injury minimized?
Definition

*Control hypoxia, hypotension, hypercarbia, intracranial HTN

*Prevent cerebral ischemia

*Maintain cerebral perfusion

Term
Patients with a GCS < ____ should be intubated early and mechanically ventilated.
Definition
*8
Term
What are some things to consider to ensure a patent airway?
Definition

*Clean out oral cavity

*insert OPA/NPA if needed and not contraindicated

*Do not hyperextend the neck

*Careful assessment before intubation 

Term
What should be assumed when intubating a patient with a head injury?
Definition

*Assume cervical spine injury is present (1-3% of CHI pts have c-spine fracture)

*Assume Full Stomach

*Assume an increased ICP is present

 

**How urgent is the need for intubation?

*Denitrogenate, ventilate by mask until ready

*Must have suction and O2 ready

*Assess the extent of facial fractures and soft tissue edema.

Term
For the patients without a difficult airway, the simplest, safest route for intubation is....
Definition
*Asleep rapid sequence with preoxygenation
Term
How should the patient be intubated?  What precautions should be taken in the head injured patient?
Definition

*Do not manipulate the neck, keep in neutral position
*Manual inline stabilization

*Cricoid pressure? Controversial

*Decompress stomach afterward

*Severe facial fractures, basilar skull fracture or profuse bleeding may C/I nasal intubation

*Consider fiberoptic, criocothyroidectomy or tracheostomy depending upon the type of injuries, amount of time available and the characteristics of the airway.

Term
True or False: Head injury is rarely the cause of sustained hypotension.
Definition
True
Term
How should a head injured patient be cardiovascularly managed?
Definition

*Preservation of an adequate CPP

*Restore volume status with isotonic crystalloid or colloid. NO DEXTROSE

*Keep hematocrit @ 30% to maximize O2 transport and cerebral perfusion

*Injured brain releases thromboplastin & cause coagulopathy--> DIC.

Term
How can increases in ICP be avoided in the patient with a head injury
Definition

*ICP >20mmHg demands aggressive treatment

*Elevate HOB 20-30 degrees (must be euvolemic)

*Head midline

*Hyperventilation used selectively

*Maintain normal BP

*Avoid coughing, straining, any acute rise in ICP

*Diuresis

*Seizure prophylaxis 

Term
How is a head injury diagnosed?
Definition

*CT SCAN

*Reveals the size and location of the lesion

*Degree of midline shift (>5mm shift, indicative of increased ICP)

*Presence of edema

Term
What risk is present with depressed and basilar skull fractures?
Definition

*Risk of infection 

*Depressed fractures to OR for early debridement

Term
What is the definition of a depressed skull fracture?
Definition
*A bony segment of the skull sunk below the normal thickness of the skull.
Term
What is the clinical significance of a depressed skull fracture?
Definition
*Fragments may tamponade a damaged vessel.
Term
What type of fractures are commonly depressed skull fractures?
Definition

*Open fractures

*Fractures over dural sinus

*Dural tears

*Cortical injury

Term
What are anesthetic considerations for the patient with a depressed skull fracture?
Definition

*Evaluate the patient

*1 or 2 large bore IVs

*Arterial line probably not necessary

*Foley useful

*With dural sinus laceration, prepare for blood loss

Term
What are signs of a basilar skull fracture?
Definition

*Rhinorrhea

*Otorrhea

*hemotympanum

*Battle's sign (ecchymosis over mastoid area)

*Raccoon Eyes (periorbital ecchymosis)

 

Term
What are important considerations for basilar skull fractures?
Definition

*Most resolve spontaneously

*Important to be aware of because nasal intubation is relatively CONTRAINDICATED.

*Can pass NET tip into cranium and infect CSF

*If OET is impossible, decide what is best, NET, trach or a cricothyrotomy.

Term
How do epidural hematomas typically occur?
Definition

*Disruption of the middle meningeal artery or its branches often d/t temporal bone fracture 

*75-90% are accompanied by skull fracture

Term
Epidural hematomas resulting from arterial bleeding are often.....
Definition
*A true neurosurgical emergency, may enlarge quickly.
Term
What do epidural hematomas usually result from?
Definition

*Disruption of the middle meningeal artery or its branches often due to a temporal bone fracture.

*75-90% are accompanied by a skull fracture

Term
What is the classical presentation of an epidural hematoma?
Definition

*Initial transient LOC followed by a lucid interval.

*Often normal neuro exam when lucid

*Lacerated vessel clots or spasms.

*H/A begins as hematoma enlarges, LOC decreases and signs of increasing ICP occur.

*As impending herniation nears, dilation for ipsilateral pupil and contralateral extremity weakness may occur w/ decerebrate positioning.

Term
What is the mortality rate if coma occurs in epidural hematoma?
Definition
*40%
Term

Patients with an epidural hematoma are often ____________ masked by HTN or normotension.

 

Definition
*Hypovolemic
Term
What occurs when an epidural hematoma is surgically decompressed?
Definition

*ICP is rapidly reduced

*The driving force causing HTN is removed

*Blood pressure decreases

*Adjust anesthesia and be aware of when the clot is being removed!

Term
What should be available for the surgical evacuation of an epidural hematoma?
Definition

*Arterial line

*2 large bore IVs

*2-4 units PRBC

Term
How should the anesthetist manage evacuation of an epidural hematoma?
Definition

*Titrate anesthetics carefully

*May hyperventilate

*Be aware of when clot removal occurs.

*Do not delay surgical intervention for line placement

*Expand volume using isotonic crystalloids and blood products.

Term
What are common causes for subdural hematomas?
Definition

*Acceleration-deceleration injury--> stretching and damage to parasagittal bridging veins

*Can occur spontaneously d/t aneurysm, neoplasm, or coagulopathy.

Term
What are three types of subdural hematomas?
Definition

*Acute

*Subacute

Chronic

Term
In what time frame do acute subdural hematomas occur?
Definition
*Within 72 hours of injury
Term
What is the mortality of an acute subdural hematoma and what implications does treatment delay >4 cause?
Definition

*Mortality 40-70%

*If >4 hour treatment delay Mortality rises to 80-90%.

Term
What happens to the brain after an acute subdural hematoma?
Definition

*Severe brain injury 

*Acute brain swelling

Term
What is the treatment of a subdural hematoma?  How can Acute brain swelling compromise this?
Definition

*Craniotomy & Clot removal

*Often stay intubated

*ICP monitored post-op

*Acute brain swelling may complicate closure after SDH evacuated.

Term
What is the anesthetic management of an acute SDH?
Definition

*If arterial bleed is expected:

*Need 2 large bore IVs

*4u PRBCs

*A-line

Term
In what time frame do subacute SDH occur?  How do the outcomes compare to acute SDH?
Definition

*3-15 days post injury

*Often better d/t not severe diffuse brain injury with swelling.

Term
In what time frame do chronic SDH occur?
Definition

*May be >2 weeks post injury.

*Develop slowly until symptomatic

*May be no history of trauma

Term
In what type of patients do chronic subdural hematomas occur in?
Definition

*Patients >50yrs, alcoholics, epileptics, bleeding disorders.

*The brain is often atrophied and there is room for clot accumulation

Term
How are chronic subdural hematomas treated?
Definition

*Clinical signs variable

*Often ICP is not elevated

*Craniotomy or trephination

*Should be well hydrated

*Individualize plan

*Foley required

Term
What is a diffuse axonal injury?
Definition
*Shearing injury that tears into the cerebral substance and causes hemorrhage into the white matter. Destroys axons.
Term
What is the most common cause of vegetative state and severe disability after blunt trauma?
Definition
*Diffuse axonal injury
Term
How do diffuse axonal injuries occur?
Definition

*Injury occurs immediately upon impact 

*Severe rotation or deceleration injuries, GSWs, HTN bleed, brain tumor, or abscess.

*Immediate bleed with tissue damage from severe high pressure wave causing devastating bleed on impact.

*Similar injury is intracerebral hematoma

*May be a slower hemorrhage, occurring up to 2 weeks after admission to the hospital.

*80% occur w/in 48 hours. Mortality can be up to 40%.

Term
What is the treatment for diffuse axonal injury?
Definition

*May not be operable

*Large, localized lesions producing symptoms should be evacuated.

*Small or deep-seated lesions are not operated on 

*Treat as if patient has increased ICP.

Term
Why are trephination or burr holes done?
Definition

*Procedure to rapidly decompress deteriorating brain

*Evacuate hematoma, drain ventricle or biopsy.

Term
How are burr holes created?  What type of anesthesia may be used in the appropriate patient?
Definition

*Small hole drilled through skull to the epidural space, the subdural space or thru the meninges to reach the ventricles.

*Cranium removed by using twist drill.

*May use local with IV sedation in the appropriate patient.

Term
What is the preoperative anesthetic management for burr holes?
Definition

*Prevent secondary injury

*Rapid assessment (Airway, CV, Neuro, volume status)

*Check IV access

*PMH

*Blood available?
*Premedication not preferred- if combative sedate and oxygenate

Term
What is the anesthetic management induction for burr holes?
Definition

*A-line w/ abgs

*Avoid swings in BP and HR with induction

*Keep CPP >70

*Augment volume status

*RSI- lidocaine, narcotics, BB. Pretreat or prime.

*Prop, Pent or Etomidate

*Succ the best for RSI NDMRs are accepatble 

*Secure ETT out of surgical field

*Secure all other lines and monitors prior to prep

Term
What is the anesthetic management during maintenance for burr holes? 
Definition

*Adequate anesthesia before pin-type head holder if used.

*Keep deeply paralyzed

*Use Forane
*Ask surgeon about BP and Hypervent

*If brain is very swollen and not responsive to measures to decrease ICP, d/c inhalational agent and use TIVA.

*Pentothol dose: 5-25mg/kg over 5-10 min.  Infusion 4-10mg/kg/hr.

*May need inotrope for BP support

*Avoid hyperthermia

*Check coags

*Administer adequate volume

*Maintain hemodynamics

*NO Dextrose or hypoosmolar

*Some advocate hypertonic or ffp/hespan

Term
What is the anesthetic management during emergence for burr holes?
Definition

*Watch ETT during dressing application

*Communicate with surgeon: extubate or keep intubated.

*Consider keeping intubated if: multiple trauma victim, decreased LOC preop, hypothermic.

*If keeping intubated keep deep for transport, keep paralyzed, monitor during transport and elevate HOB.

*If extubating take your time, control ICP and BP- labatelol is helpful.

Term
What are common cardiopulmonary sequelae after HI?
Definition

*Often attributable to sympathetic hyperactivity

*Increase in HR, BP, CO, VO2, shunt, V/Q mismatch, decreased SVR

*Cardiac dysrhythmias and EKG changes

*Prone to aspiration atelectasis, pneumonia, ARDS.

Term
What sequelae of HI is relatively rare and results from massive sympathetic outflow after injury?
Definition

*Neurogenic Pulmonary Edema

*Causes increased pulmonary venous pressure & cap permeability. 

*Very rapid intraalveolar hemorrhage and Pulmonary edema.

Term
What are S&S of neurogenic Pulmonary edema?
Definition
*Cyanosis, diaphoresis, pallor, dyspnea, weak pulse, tachycardia, pink, frothy sputum.
Term
How is Neurogenic Pulmonary edema treated?
Definition

*Usually associated with an acute rise in ICP?

*May not respond to conventional treatment.

*Treatment: reduction of ICP, block of sympathetic hyperactivity, support the pulmonary system.

Term
What is released after brain tissue damage and what can this result in?
Definition

*Thromboplastin is released

*Causes accelerated fibrinolysis and possible DIC.

*High mortality

Term
What metabolic derangements occur after HI?
Definition

*Diabetes insipidus

*SIADH

Term
What are the S&S of Diabetes Insipidus and how is it treated?
Definition

*Polyuria (>3L/day)

*Polydipsia

*Hypernatremia

*High serum OSM

Treatment: Water replacement. NO Na+, Vasopressin

Term
What are the S&S of SIADH and what is the treatment?
Definition

*Usually begins 3-15 days after trauma lasting for 10-15 days.

*Signs: water intoxication, hyponatremia, low serum OSM, renal Na+ excretion, urine osm >serum osm, N/V, irritability, personality changes.

*Treatment: Water restriction. Hypertonic saline, possibly a diuretic.

Term
What complications can result from HI?
Definition

*Focal neurologic deficits

*Hydrocephalus

*Seizures

*CSF Fistulae

*Vascular injuries

*Infection

*Brain Death

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