Breathing for the Head

John Peterson, DOKU School of Medicine - Wichita

Disclosures

• I’ve known Alan and Jeff for a while……

Objectives

• Neurological injuries• Physiological effects • Airway management• Ventilator management

Neurological injuries

• Disturbances in consciousness• Encephalopathy• Traumatic brain injury• Acute Myelopathy• Ischemic stroke• Intracerebral hemorrhage• Subarachnoid hemorrhage• Brain tumors• Status epilepticus• Venous thrombosis

– Cerebral Sinus– DVT/PE Bhardway, Anish, et. al., ed, Handbook of

Neurocritical Care, 2nd ed. Springer, 2011. pp xi - xiii

Disturbances in Consciousness• Drowsy• Stupor• Minimally conscious state• Vegetative state– Restored sleep/wake cycle

• Locked – in syndrome• Coma• Brain death

Encephalopathy• Vascular• Trauma• Neoplasm• Seizure• Organ Failure• Metabolic• Endocrine• Pharmacologic• CNS infection• Systemic infection• Inflammatory and immune – mediated encephalitisBhardway, Anish, et. al., ed, Handbook of

Neurocritical Care, 2nd ed. Springer, 2011, p 289

Traumatic Brain Injury

• Primary injury• Secondary injury– May be more injurious– Hypoxia and hypoperfusion most likely are the

most critical factors in secondary injury

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 308

Acute Myelopathy

• Traumatic• Degenerative spine• Neoplastic• Inflammatory• Systemic disease• Bacterial and viral infections• Vascular• Toxic/Metabolic

Stroke

• Defined– Focal neurological deficit that has an arterial

distribution that correlates with specific region of the brain

Normal Brain

Ischemic stroke

• Focal neurological deficit corresponding to arterial territory

• Transient ischemic attack (TIA)– Symptoms resolve in less than 24 hrs• Typically less than 1 hr

• Reversible Ischemic Neurologic Deficit (RIND)– Symptoms lasting 24 – 72 hrs

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 341

Ischemic Stroke

Ischemic stroke• Embolic

– Cardiac– Artery to artery embolus– Paradoxical embolus

• Thrombotic– Intracranial atherosclerosis– Lipohyalinosis– Arterial dissection– Arteritis– Fibromuscular dysplasia– Vasospasm– Hypercoaguable states

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 342

Ischemic Stroke• Modifiable – Diabetes mellitus– Hypertension– Smoking– Hypercholesterolemia– Coronary artery disease

• Non-modifiable– Age– Male – Family history

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 342

Intracerebral Hemorrhage

Intracerebral Hemorrhage

• 10 – 15% of all strokes• 30 day mortality: 35 – 52%• Only 20% are independent functional at 6

months• Etiology– Primary

• Secondary to hypertension

– Secondary• Aneurysmal, AVM, Tumor, Amyloid angiopathy,

Coagulopathies, Trauma

Intraventricular Hemorrhage

Subarachnoid Hemorrhage

• Trauma– Most common cause

• Spontaneous– 80% Aneurysmal– 10 – 15% Perimesencephalic nonaneurysmal

hemorrhage– 5% Nonaneurysmal

• 2 – 5% of all strokes

Subarachnoid Hemorrhage

Vasospasm

• Occurs between days 4 -12– Lasts up to 21 days

• Monitoring with transcranial doppler (TCD)• Treatment for symptomatic vasospasm– Triple H

• Hypertension• Hypervolemia• Hemodilution

– Angiography with balloon dilation or intra-arterial calcium – channel blocker infusion

Epidural Hematoma Subdural Hematoma

Post-Cardiac Arrest Brain Injury

• Therapeutic hypothermia– Indicated for out-of-hospital ventricular fibrillation

arrest – Possible benefit with asystole and PEA– 55% of the hypothermia group had a favorable

outcome vs 39% in the normothermia group• At 6 months 41% of the hypothermia group died vs 55%

of the normothermia group

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 393

Venous Thrombosis

• Cerebral Sinus– Rare cause of stroke

• Thrombophilia is most common cause• Systemic anticoagulation required

• DVT/PE– 79% of pulmonary embolism originates from a lower extremity

deep vein thrombosis– Neurological conditions predisposing to VTE

• Spinal cord injury• Traumatic brain injury• Ischemic stroke• Intracerebral hemorrhage• Malignant glioma

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 433-434, 506-507

Venous Thrombosis• Deep Vein Thrombosis– Risk Factors

• Venous valvular insufficiency• Right-sided heart failure• Postoperative period• Prolonged bedrest• Extremity trauma• Malignancy and cancer therapy• Pregnancy and postpartum period• Hormone therapy• Spinal cord injury• History of venous thromboembolism• Hypercoagulable state Bhardway, Anish, et. al., ed, Handbook of Neurocritical

Care, 2nd ed. Springer, 2011, p 506-507

Malignant Hyperthermia

• Autosomal dominant condition• Triggers– Halogenated inhalational anesthetics– Succinylcholine– Extreme stress, vigorous exercise and heat

exposure• Risk Factors– Myopathies

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 437

Malignant Hyperthermia• Signs and symptoms

– Unexpected rise in end-tidal CO2 > 55 or PaCO2 >60– Increased minute ventilation– Unexplained tachycardia, ventricular tachycardia or fibrillation, labile blood

pressure, congestive heart failure– Metabolic acidosis with elevated serum lactate– Altered mental status (when anesthetic is stopped)– Generalized muscle rigidity, masseter rigidity (despite neuromuscular blockade),

rhabdomyolysis– Acute renal failure– Hyperkalemia– Hyperthermia (Temperature can rise 1 – 2 C˚ q 5 min up to 44˚C)

• This is a late finding

– DIC• Especially with temp > 41˚C

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 438

Malignant Hyperthermia

• Management– Stop offending agent– Admit to ICU– Increase minute ventilation to normalize PaCO2

– Body cooling• NG icy lavage, ice packs, fans, surface or invasive cooling systems• Target temp of 38.5

– Dantrolene• Continue for 3 days IV or PO dosing• Monitor for excessive muscle weakness or hepatotoxicity

– Monitor for recrudescenceBhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 438

Neuroleptic Malignant Syndrome

• Risks– Prior physical exhaustion and dehydration– Previous episode of NMS – Exposure to antipsychotic drugs

• Signs and symptoms– Develop within 24hrs – 1 month after exposure to

antipsychotic drugs– Regression within 1 wk – 1 month after discontinuation

of drug• 10% Mortality

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 435-436

Brain Tumors

• Second most common cause of death from intracranial disease• 33% overall 5 year survival• 33% of all tumors are gliomas

– 67% are high grade• Metastatic tumors are the most common brain neoplasm

– Lung (18 – 64%)– Breast (2 – 21%)– Melanoma (4 – 16%)– Colorectal tumors (2 – 12%)– Renal cell carcinoma (1 – 8%)– Lymphoma (< 10%)– Unknown origin (1 – 18%)

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 445-446

Brain Tumors

Brain Tumor

Brain Tumors

• Headache• Seizure• Progressive focal neurological deficits• Visual defects• Altered mental status• Intracerebral hemorrhage• Intracranial pressure elevation

Hydrocephalus

• Caused by impaired cerebrospinal fluid flow, reabsorption or excessive production

• Cerebrospinal fluid– Forms at 0.3mL/min • 20mL/hr• 500mL/day

– Total volume ~150mL• 75mL in cranial vault

– Normal pressure ~10mmHgBhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 469. 471

Hydrocephalus

Hydrocephalus

Neuromuscular Disorders• Acute generalized weakness

– CNS• Bilateral hemispheric • Brainstem• Spinal cord

– Motor neuron• West Nile infection• Poliomyelitis• Enterovirus infection

– Neuromuscular junction• Myasthenia gravis• Lambert-Eaton myasthenic syndrome• Organophosphate poisoning• Botulism• Tick Paralysis• Hypermagnesemia• Snake/insect/marine toxins Bhardway, Anish, et. al., ed, Handbook of Neurocritical

Care, 2nd ed. Springer, 2011, p 478

Neuromuscular Disorders

• Acute generalized weakness causes cont.– Neuropathies

• Guillain – Barré syndromes• Critical illness polyneuropathy• Chronic idiopathic demyelinating polyneuropathy• Toxic neuropathies• Vasculitic neuropathy• Porphyric neuropathy• Diptheria• Lymphoma• Carcinomatous meningitis• Acute uremic polyneuropathy• Eosinophilia-myalgia syndrome

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 478

Neuromuscular Disorders

• Acute generalized weakness causes cont.– Myopathies

• Critical illness myopathy• Dermatomyositis• Polymyositis• Periodic paralysis/hypokalemic myopathy• Myotonic dystrophy• Acid maltase deficiency• Muscular dystrophies• Mitochondrial myopathies• Corticosteroid-induced myopathy

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 478

Neuromuscular Disorders• Causes of acute respiratory muscle weakness

– CNS• Diseases of high cervical cord or medulla

– Motor neuron disease– Neuromuscular junction

• Myasthenia gravis• Lambert-Eaton myasthenic syndrome

– Neuropathies• Idiopathic bilateral phrenic nerve paresis• Guillain-Barré syndrome (rare)• Neuralgic amyotrophy• Large artery vasculitis• Multifocal motor neuropathy

– Myopathies• Acid maltase deficiency Bhardway, Anish, et. al., ed, Handbook of Neurocritical

Care, 2nd ed. Springer, 2011, p 478

Neuromuscular Disorders• Causes of acute predominantly bulbar weakness

– CNS• Brainstem diseases• Bilateral white matter diseases• Syrinx

– Motor neuron• Amyotrophic lateral sclerosis• Kennedy disease

– Neuromuscular junction• Myasthenic gravis• Lambert-Eaton myasthenic syndrome• Botulism

– Neuropathies• Guillan-Barré syndrome (rare)• Carcinomatous meningitis• Skull base tumor or metastases• Miller-Fisher disease• Sarcoidosis• Basilar meningitis

– Myopathies• Dermatomyositis• Polymyositis• Oculopharyngeal muscular dystrophy• Myotonic dystrophy• Distal myopathy with vocal cord paralysis Bhardway, Anish, et. al., ed, Handbook of Neurocritical

Care, 2nd ed. Springer, 2011, p 479

Neuromuscular Disorders• Acute failure of the autonomic nervous system

– CNS• Diseases affecting the hypothalamus, brainstem, medulla, high cervical cord• R insular stroke

– Neuromuscular junction• Lambert-Eaton myasthenic syndrome• Botulism

– Neuropathies• Diabetic autonomic neuropathy• Amyloid neuropathy• Guillain-Barré with predominant dysautonomia• Paraneoplastic dysautonomia• Connective tissue disorders

– Sjogrens– Systemic lupus erythematosus– Infectious– Chagas– HIV– Leprosy– Diptheria

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 479

Neuromuscular Disorders• Indications for ICU admission

– Respiratory weakness• FVC < 40ml/kg• NIF < - 40 cmH2O• > 30% decline in FVC or NIF in 24 hrs• Signs of fatigue or dyspnea• Significant neck flexor weakness or poor cough• CXR

– Infiltrates, atelectasis or pleural effusion

– Dysphagia/inability to protect airway• Increased aspiration risk• Bulbar dysfunction/bilateral facial weakness• Failed swallow evaluation

– Autonomic instability• Dysrhythmia• Blood pressure lability• Profound sensitivity to sedatives

– Planned interventions• Plasma exchange• Frequent vital checks or intensive nursing care• Rapid onset of symptoms (< 7 days)

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 480

Neuromuscular Disorders

• Intubation indications– Consider early intubation• May reduce pulmonary complications

– FVC < 20 mL/kg– NIF < - 30 cmH2O

– PaO2 < 70 (decrease by > 50% in 24 hrs) on room air

– Hypoventilation (PaCO2 > 45)– Dysphagia

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 480

Neuromuscular disorders

• Extubation criteria– Pressure support of 5 with PEEP 5 for > 2hrs

(prolonged SBT)– Some evidence for PS of 0 with PEEP of 5 or T-

piece predicts more successful extubation– Successful secretion management

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 481

Status Epilepticus

• A seizure that persists a sufficient length of time or is repeated frequently enough to produce a fixed and enduring epileptic condition

• Historically, is defined by a seizure lasting 30 min and should be considered for seizures lasting 5 – 10 min

• Nonconvulsant status epilepticus should be considered with coma patients with unclear etiology– May occur in as many as 8 -34% of critically ill patients

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 489

Status Epilepticus• Etiologies– Neurovascular– Tumor– CNS Infection– Inflammatory disease– Traumatic brain injury– Primary epilepsy– Hypoxia/ischemia– Drug/substance toxicity or withdrawl– Fever– Metabolic abnormalities

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 491

Status Epilepticus

• Medical treatment– May require inducing a coma– Neuromuscular blockade • Will not stop the seizure, only the motor manifestation

• Airway and ventilator management– May not be required for nonstatus seizure– Will be required for induced coma

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 499

Spinal Cord Injury

• Trauma is the most common cause– ~ 50% are motor vehicle related– 24% related to falls– 9% sports injury– 11% assault– > 50% involve the cervical spine

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 325

Spinal Cord Injury

• Diaphragm– Innervated by cervical spine segments C3 – C5

• Injury at or above this level results in immediate ventilatory failure

– Below the diaphragmatic level• Diaphragm is preserved• Intercostals are compromised• Decreased vital capacity, maximal inspiratory support and

decreased expiratory force• Spasticity develops leading to improved forced vital

capacity and maximal expiratory forceBhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 333

Spinal Cord Injury

• Post injury– Rapid shallow breathing

transiently compensates for the injury

– Atelectasis develops– 1/3 will require intubation– Consider intubation when

VC < 1L– Intubate if decreased LOC,

impaired cough or unable to manage secretions

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 333

Neurogenic Pulmonary Edema

• Occurs in with severe acute neurological injury• Incidence– 40% of head injury patients– 90% intracerebral hemorrhage

Neurological evaluation

Neurological Evaluation

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 313

Physiological Effects of

Neurological Injury

• Cerebral Blood Flow– Controlled by the arteriole constriction and

relaxation• Hypoventilation– Hypercarbia– Hypoxia

Autoregulation

metrohealthanesthesia.com

Cerebral Perfusion Pressure (CPP)

• CPP = Mean arterial pressure (MAP) – Intracranial pressure (ICP)/Central venous pressure (CVP)

Monro-Kellie Doctrine

Monro-Kellie Doctrine

Hyperventilation

• PaCO2 – 1 mmHg change in PaCO2 produces

1 ml/100 Gm/min change in CBF (in same direction) • Transient effect (wanes in 6-8 hours)

• Normal CBF – PaCO2 = 40 mmHg

Management

• ABC– Airway• GCS < 8 or rapid worsening GCS• Uncontrolled seizures

– Intubation• Controlled induction

– Avoiding hypo or hypertension– Consider lidocaine to blunt elevation in ICP

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 357

Management

• ABC– Breathing

• Higher mortality rate in neurological patients than nonneurologic patients despite a lower incidence of extracerebral organ dysfunction

• Avoiding secondary injury– Lung Protective Ventilation

– Circulation• Target CPP 60 – 80 mmHg

– ICP monitoring• Necessary to accurately measure CPP

Pelosi, et. al. Crit Care Med 2011 Vol. 39, No. 6

Ventilator management

• Mode• PEEP• Oxygenation– O2 saturation > 90%

– PaO2 > 60 mmHg

• ARDS– Lung protective ventilation

• Neurogenic pulmonary edemaBullock, R, M.D., Ph.D., Deputy Editor, Povlishock, J., Ph.D. Editor-in-ChiefGuidelines for the Management of Severe Traumatic Brain Injury of Severe Traumatic Brain Injury 3rd ed, 2007 Brain Trauma Foundation, Inc.

PEEP

• PEEP– Increases

• Intrathoracic pressure• Peak inspiratory pressure• Mean airway pressure

– Decreases• Venous return• Mean arterial pressure• Cardiac output

PEEP

• PEEP 5 – 15 mmHg– Generally tolerated in patients at risk for elevated

ICP– Elevated ICP should be closely monitored with

changes in PEEP

Venous Drainage

Extubation

• Neurosurgical patient– GCS = 4 were successfully extubated• Intact cough and gag

– Strategy• Is the neurological injury reversible?• What is the duration of injury?

– If long term neurological injury anticipated• Early tracheostomy

Extubation

• Criteria– Signs of appropriate muscle strength– Vital capacity > 15 – 20 mL/kg– Mean inspiratory pressure < -20 to -50 cmH2O

– FiO2 < 40% and PEEP ≥ 5 cmH2O– No fever, infection or other medical complications

Pulmonary toilet

• Endotracheal suctioning on cerebral oxygenation in traumatic brain-injured patients– Increased ICP– Increased CPP– No change in oxygenation

Kerr, et al, Critical Care Medicine, Volume 27(12), December 1999, pp 2776-2781

Monitors

• ICP Monitors– Bolt• Pressure monitor

– External Ventricular Drain (EVD)• Pressure monitor• Drainage of CSF

– Parenchymal ICP monitor (Codman)

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 314 - 315

• Tissue oxygenation– Jugular venous saturation – Brain tissue oxygenation (Licox)– Near – infrared spectroscopy

• Tissue metabolic activity– Microdialysis catheter

Monitors

Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011, p 314 - 315

Summary

• Recognition of neurological injury• ABCs• Intubation and Ventilation• Extubation

References

1. Bhardway, Anish, et. al., ed, Handbook of Neurocritical Care, 2nd ed. Springer, 2011.