FOCUS Annual Fall Classic 2018

Respiratory Care of the Patient with Traumatic Brain Injury

Daniel W. Chipman, BS, RRT

Assistant Director of Respiratory Care

Massachusetts General Hospital

Boston, Massachusetts

Respiratory Care of the Patient with TBI

• Overview

• Glascow Coma Scale (GCS)

• Abreviated Injury Score (AIS)

• Primary vs secondary injury

• Intubation

• Ventilation and Oxygenation

• Mechanical Ventilation

• Monitoring

• Extubation/tracheostomy

TBI in the United States

• An estimated 2.8 million people sustain a TBI annually. Of them: • 50,000 die,• 282,000 are hospitalized, and• 2.5 million, nearly 90%, are treated and released from an emergency department.

• TBI is a contributing factor to a third (30%) of all injury-related deaths in the United States.

• Every day, 153 people in the United States die from injuries that include TBI.

• Most TBIs that occur each year are mild, commonly called concussions.

• Direct medical costs and indirect costs of TBI, such as lost productivity, totaled an estimated $60 billion in the United States in 2000.

From the Centers for Disease Control and Prevention 2017

TBI by Age

• Children aged 0 to 4 years, older adolescents aged 15 to 19 years, and adults aged 65 years and older are most likely to sustain a TBI.

• In 2012, an estimated 329,290 children (age 19 or younger) were treated in U.S. EDs for sports and recreation-related diagnosis of concussion or TBI.

• Adults aged 75 years and older have the highest rates of TBI-related hospitalization and death.

Causes of TBI inthe United States

Eye Opening Response

Spontaneous--open with blinking at baseline 4 points

To verbal stimuli, command, speech 3 points

To pain only (not applied to face) 2 points

No response 1 point

Verbal Response

Oriented 5 points

Confused conversation, but able to answer questions 4 points

Inappropriate words 3 points

Incomprehensible speech 2 points

No response 1 point

Motor Response

Obeys commands for movement 6 points

Purposeful movement to painful stimulus 5 points

Withdraws in response to pain 4 points

Flexion in response to pain (decorticate posturing) 3 points

Extension response in response to pain (decerebrate posturing) 2 points

No response 1 point

Glascow Coma Scale (GCS)

Categorization:

Coma: No eye opening, no ability to follow commands, no word

verbalizations (3-8)

Head Injury Classification:

Severe Head Injury----GCS score of 8 or less

Moderate Head Injury----GCS score of 9 to 12

Mild Head Injury----GCS score of 13 to 15

Glascow Coma Scale (GCS)

Brain anatomy

• Cerebral Cortex• Frontal lobe

• Parietal lobe

• Occipital lobe

• Temporal lobe

• Brain Stem• Medulla

• Cerebellum

Frontal Lobes: Most anterior, right under the forehead.Functions•How we know what we are doing within our environment (Consciousness)•How we initiate activity in response to our environment•Judgments we make about what occurs in our daily activities•Controls our emotional response•Controls our expressive language•Assigns meaning to the words we choose•Involves word associations•Memory for habits and motor activitiesObserved Problems•Loss of simple movement of various body parts (Paralysis)•Inability to plan a sequence of complex movements needed to complete multi-stepped tasks, such as making coffee (Sequencing)•Loss of spontaneity in interacting with others. Loss of flexibility in thinking•Persistence of a single thought (Perseveration)•Inability to focus on task (Attending)•Mood changes (Emotionally Labile)•Changes in social behavior. Changes in personality•Difficulty with problem solving•Inability to express language (Broca's Aphasia)

Parietal Lobes: near the back and top of the head.Functions•Location for visual attention•Location for touch perception•Goal directed voluntary movements•Manipulation of objects•Integration of different senses that allows for understanding a single conceptObserved Problems•Inability to attend to more than one object at a time•Inability to name an object (Anomia)•Inability to locate the words for writing (Agraphia)•Problems with reading (Alexia)•Difficulty with drawing objects•Difficulty in distinguishing left from right•Difficulty with doing mathematics (Dyscalculia)•Lack of awareness of certain body parts and/or surrounding space (Apraxia) that leads to difficulties in self-care. Inability to focus visual attention•Difficulties with eye and hand coordination

Occipital Lobes: Most posterior, at the back of thehead.Functions•VisionObserved Problems•Defects in vision (Visual Field Cuts)•Difficulty with locating objects in environment•Difficulty with identifying colors (Color Agnosia)•Production of hallucinations Visual illusions -inaccurately seeing objects•Word blindness - inability to recognize words•Difficulty in recognizing drawn objects•Inability to recognize the movement of an object (Movement Agnosia)•Difficulties with reading and writing

Temporal Lobes: Side of head above ears.Functions•Hearing ability•Memory acquisition•Some visual perceptions•Categorization of objectsObserved Problems•Difficulty in recognizing faces (Prosopagnosia)•Difficulty in understanding spoken words (Wernicke's Aphasia)•Disturbance with selective attention to what we see and hear•Difficulty with identification of, and verbalization about objects•Short-term memory loss. Interference with long-term memory Increased or decreased interest in sexual behavior•Inability to catagorize objects (Categorization)•Right lobe damage can cause persistent talking•Increased aggressive behavior

BRAIN STEM: Deep in Brain, leads to spinal cord.Functions•Breathing Heart Rate Swallowing Reflexes to seeing and hearing (Startle Response)•Controls sweating, blood pressure, digestion, temperature (Autonomic Nervous System)•Affects level of alertness•Ability to sleep•Sense of balance (Vestibular Function)Observed Problems•Decreased vital capacity in breathing, important for speech•Swallowing food and water (Dysphagia)•Difficulty with organization/perception of the environment•Problems with balance and movement•Dizziness and nausea (Vertigo)•Sleeping difficulties (Insomnia, sleep apnea)

CEREBELLUM: Located at the base of the skull.Functions•Coordination of voluntary movement Balance and equilibrium•Some memory for reflex motor actsObserved Problems•Loss of ability to coordinate fine movements•Loss of ability to walk•Inability to reach out and grab objects•Tremors. Dizziness (Vertigo)•Slurred Speech (Scanning Speech)•Inability to make rapid movements

Intracranial Pressure (ICP)

• Normal = 5 to 15 mmHg

• ICP monitoring is recommended in most comatose patients with severe head injury

• ICP should be treated when above 20mmHg, but maintenance of CPP is probably more important

• Increased ICP may be caused by:• tracheal intubation

• Coughing

• ETT suctioning

• Patient/ventilator asynchrony

Monroe-Kellie Doctrine

intracranial (constant) = v.brain + v.CSF + v.blood + v.mass lesion

Monro A. Observations on the structure and function of the nervous system. Edinburgh, Creech & Johnson 1823 p.5

Kellie G. An account of the appearances observed in the dissection of two of the three individuals presumed to have perished in the storm of the 3rd, and whose bodie were discovered in the vicinity of Leith on the morning of the 4th November 1821 with some reflections on the pathology of the brain. Trans Med Chir Sci, Edinburgh 1824;1:84-169

Indications for ICP Monitoring

trauma.org 5:1 2000

Cerebral Perfusion Pressure (CPP)

• Difference between the Mean Arterial Pressure (MAP) and the Intracranial Pressure (ICP)

• Pressure gradient driving cerebral blood flow and oxygen and metabolite delivery

• CPP is reduced after TBI and must be restored

• CPP = MAP - ICP

CPP

• Critical threshold:• 70 to 80 mmHg

• 35% reduction in mortality

• Mortality increases 20% for each 10 mmHg loss of CPP

• May be restored by:• Decreasing ICP (< 20 mmHg)

• Increasing MAP• therapeutic level

• avoid hypotension (MAP < 90 mmHg)

Oxygen Monitoring

• Jugular bulb venous oxygen monitoring

• PbtO2 monitoring

Jugular Bulb Venous Oxygen Oonitoring

• Indication of cerebral oxygenation (O2 delivery) and cerebral metabolism (O2 consumption)

• Normal range 55 to 71%

• Monitors global oxygenation

• Sustained SjvO2 < 50 mmHg indicates cerebral ischemia

Randall M. Schell and Daniel J. ColeAnesth Analg 2000;90:559–66

PbtO2 Monitoring

• Monitors focal oxygenation (site of injury)

• Normal range 35 to 50 mmHg

• < 15 mmHg indicates ischemia

• Associated with reduced morbidity and mortality

• PbtO2 monitoring combined with ICP/CPP based treatment associated with best outcomes

Nangunoori, et alNeuro Crit Care 2011

Invasive Multimodal MonitoringRationale:

1) Detect scalp-negative seizures, edema, vasospasm impacting cerebral oxygen delivery/consumption

2) Diagnose reversible causes of coma and neurologic injury by understanding the relationships between multiple physiologic factors and their trend over time (e.g., vasospasm obscured by coma, ICP elevation related to agitation vs. spontaneously occurring; ICP elevation with normal vs. abnormal CPP; brain tissue hypoxia related to sedation holds, brain tissue hypoxia or ICP elevation related to epileptiform activity).

3) Tailor neurocritical care management to patient-specific factors including parameters impacting

perfusion (supply) and metabolism (demand): BP, CPP, edema, seizure/IIC activity, hypovolemia,

sedatives, temperature

4) Evaluate response to treatment (CPP optimization, hyperosmolar therapy, spasmolysis, AED trials)

Invasive Multimodal Monitoring

• Inclusion Criteria:1. Traumatic brain injury

2. GCS≤8 on admission or after neurologic decline

3. Admission to Lunder 6 Neuro-ICU from ED or after OR management.

4. Age > 18 years

• Exclusion Criteria:1. Contraindication to placement of intracranial monitor (severe coagulopathy, CMO status)

Invasive Multimodal Monitoring

• Ideally placed on the side at risk for secondary tissue injury• Injures or contused

• Viable non-infarcted

• Side of the dominant injury

• If significant hematoma is present on side of dominant injury:• Placed on contra-lateral side

Invasive Multimodal Monitoring

TBI

• Primary injury• Occurs at the scene and is usually the control of the patient care team

• Secondary injury• Anything that occurs to augment the primary injury

• Prevention of secondary is the aim of the management

Management of Severe TBI

• Establish monitoring parameters for treatment

• Enhance cerebral oxygen delivery

• Optimize CPP

• Optimize management of increased ICP

5 Key Principles for ICU Management of Head Injury• Normotension

• Normoxia

• Normocapnea

• Normothermia

• Normoglycemia

Assessment and Plan

• Secure airway

• Maintain neck in neutral position

• Obtain serial CT scans

• Consider placement of ICP monitor/ventriculostomy and PbtO2

• Place arterial and CVP lines

Emergency Department

• Airway

• Intubate• GCS 3-8

• unable to protect airway

• SaO2 100%, PaCO2 35-40 mmHg

• MAP > 90 mmHg

• Large bore IVs, labs

• NG/Foley

• Mannitol – 1 g/kg for posturing or unequal/non-reactive pupils

Mannitol and TBI

• Short term use increases serum osmolarity and draws fluid from the brain

• Long term it may cross the blood brain barrier and increase swelling.

No difference between the 2 medications could be found with respect to the extent of reduction of ICP or duration of action

Mannitol therapy for raised ICP may have a beneficial effect on mortality when compared to pentobarbital treatment, but may have a detrimental effect on mortality when compared to hypertonic saline. ICP-directed treatment shows a small beneficial effect compared to treatment directed by neurological signs and physiological indicators. There are insufficient data on the effectiveness of pre-hospital administration of mannitol

Prepare for ICP/LICOX Insertion

• Arterial and central lines

• Administer fluids to keep CVP 5 – 10 mmHg• Albumin/NS

• Blood products

• Reverse DIC – FFP, Cryo, platelets for abnormal coags

• Maintain MAP > 90 mmHg or CPP > 70 mmHg• Neosynephrine, Dopamine

• Titrate PaCO2 to keep PbtO2 > 20 mmHg

• Consider craniotomty for unresponsive ICP

Goals:SaO2 100%PaCO2 35-40 mmHgMAP > 90 mmHgPbtO2 > 20 mmHgICP < 20 mmHg

ICU Phase l: Initial 24 hours

• Maintain Goals• If PbtO2 < 15: FIO2 100% (up to 24-48 hours, then

decrease to 30 to 50%)

• Priorities: to decrease FIO2• Titrate PaCO2 to keep PbtO2 > 20 mmHg• Give volume: CVP 5 – 10 mmHg

• Fluids until euvolemic, vasopressors to raise MAP

• Determine optimal CPP for patient (70 mmHg)• Consider early Propofol 10-15 ug/kg/min• ICP < 20• Maintain normothermia and appropriate antibiotic

coverage

Goals:SaO2 100%PaCO2 35-40 mmHgMAP to keep CPP > 70mmHgPbtO2 > 20 mmHgICP < 20 mmHg

ICU Phase ll: > 24 Hours After Admission

• Maintain FIO2 to keep PaO2 > 80

• Titrate PaCO2 to balance ICP < 20 mmHg and PbtO2 > 20 mmHg

• Determine optimal CPP for patient• CVP 5-10 using fluids• Vasopressors to increase MAP when euvolemic

• Sedate – continuous Propofol or Versed

• Pain control – continuous morphine or fentanyl

• Temp 36-37o C, using cooling measures

• Mannitol0.25-0.5 g/kg bolus if ICP >15• Keep serum osmo < 320• Fluid replacement to maintain euvolemia

• Consider neurosurgery for refractory ICP

• Consider pentobar drip if unable to control ICP

Goals:PbtO2 > 20 mmHgICP < 20 mmHg

If PbtO2 < 20 mmHg

• Increase FIO2 to 100% for 15 minutes• Drain CSF if > 20 mmHg• Increase PaCO2: decrease RR, balance with ICP• Optimize CPP: check CVP and MAP• Mannitol (if ICP > 20 mmHg)• Maintain adequate sedation and anesthesia• Consider cooling for temp > 37o C.• Start or increase propofol• Consider barbiturate therapy if refractory to other interventions• Consider paralytic if unable to maintain PaCO2 and PaO2

If PbtO2 > 20 mmHg and ICP > 20 mmHg

• Drain CSF

• Decrease PaCO2 to decrease ICP

• Optimize CPP: fluids and vasopressors to maintain CPP

• Mannitol (0.25 to 1 gm/kg IV)

• Consider paralytics or pentobarbitol for ICP control

• Start/titrate Propofol/barbiturates for ICP control

• Consider craniectomy

Phase lll: weaning

• Normalize PaCO2

• Discontinue paralytics/pentobarbitol

• Wean Propofol

• Normalize CPP/CVP

• Discontinue ICP/CSF drain

• Decrease analgesia/sedation

CO2 and Cerebral Blood Flow

• Potent vasoactive effect

• Hyperventilation causes cerebral vasoconstriction

• Decreases cerebral blood flow• Decreases ICP

• Ischemia

PEEP and TBI

• PEEP increases intrathoracic pressure

• Decreased venous drainage

• Increased cerebral blood volume and ICP

• Maintain PEEP 5 to 8 cm H2O

Protective Lung strategies and TBI

• High Vt associated with acute lung injury in patients with severe TBI

• Low tidal volume

• Moderate PEEP

Mechanical Ventilation and TBI

• Maintain target oxygenation • SaO2 > 95% and PaO2 > 80 mmHg

• Maintain target ventilation • 35-40 mmHg

• Minimize airway pressures – MAP and PEEP• Promotes cerebral venous drainage

• For multi-trauma patients you may have to make some compromise to protective lung strategies

TBI and ARDS

• 10 to 30% patients with TBI develop ARDS

• Etiology

-Aspiration -Pneumonia

-Pulmonary contusion -Massive blood transfusion

-Transfusion related acute lung injury (TRALI) -Sepsis

-Neurogenic pulmonary edema

-High tidal volume and high respiratory rate

• Increased ICU LOS and ventilator days

TBI and ARDS Balanced Approach

• TBI:• Adequate oxygenation

• Preserving cerebral venous drainage (low levels of PEEP)

• Mild hypocapnia (slightly higher Vt)

• ARDS• Low Vt

• High PEEP

• Permissive hypercapnia

Lunder 6 NSICU Ventilator Settings Protocol

Assist/ Control Ventilation

Tidal Volume 4 to 8 ml/kg PBW

Inspiratory Time <1.0 sec

Driving Pressure <15 cmH20

Plateau Pressure <28 cmH2O

PEEP 5 to 15 cmH2O

Set Rate 10 to 30/min

FIO2 to maintain SpO2 93% to 100%

Lunder 6 NSICU Ventilator Settings Protocol

Pressure Support Ventilation may be initiated if:

Team consensus to initiate

Intact ventilatory drive, sustained spontaneous breathing

FIO2 < 0.6

Pressure support level 5 to 15 cmH2O to establish a tidal volume of

6 to 10 ml/kg PBW

PEEP 5 to 15 cmH2O

FIO2 set to keep SpO2 93 to 100%

Lunder 6 NSICU Ventilator Settings ProtocolAssess for Spontaneous Breathing Trial (SBT) daily

Perform SBT if: patient breathing spontaneously, FIO2 < 0.5,

PEEP < 10 cm H2O, patient hemodynamically stable, not requiring continuous infusion of pressors or sedatives

SBT: Leave patient attached to the ventilatorPEEP < 5 cm H2O and pressure support < 5 cmH2OMaintain spontaneous breathing 30 to 60 min Discontinue SBT if:

a. SpO2 < 90% b. VT < 4 ml/kg PBWc. Respiratory Rate > 35/mind. Develops respiratory distress defined as 2 or more of the following:

i. HR > 120% of baseline

ii. BP > 150% of baseline or Systolic > 180 mmHg and Diastolic > 90 mm Hg iii. Marked accessory muscle use iv. Abdominal Paradox v. Diaphoresis vi. Marked dyspnea

Endotracheal Tube Suctioning and ICP

• ETT suctioning increases ICP

• Especially on the 4th pass of the suction catheter

• May be alleviated with lidocaine (ETT or IV)

• Preoxygenate

• Increase sedation

• Must be brief and atraumatic

Ventilator Discontinuance and Extubation

• SBT to assess ability to maintain ventilation

• Assessment of ability to protect airway prior to extubation

• Tracheostomy for patients unable to protect their airway

Summary

• TBI is a common injury associated with significant morbidity and mortality requiring prompt intervention.

• Efforts must be directed at reducing the incidence of secondary injury.

• Proper monitoring of CPP and cerebral O2 delivery is essential to improving outcomes.