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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.