Hypercapnic Respiratory Failure
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Transcript of Hypercapnic Respiratory Failure
Hypercapnic Respiratory Failure
Erik van Lunteren, M.D.
Outline
• Carbon Dioxide
• Causes of Hypercapnic Respiratory Failure
• Management of Hypercapnic Respiratory Failure
Carbon Dioxide
Carbon Dioxide: History• Discovered by Jan Baptista van Helmont around
1630 as the gas given off by burning wood, who called it sylvestre ("wood gas").
• Studied extensively by Joseph Black (1728–1799), who proved that carbon dioxide occurred in the atmosphere and that it could form other compounds. – He also identified carbon dioxide in the breath
exhaled by humans.
• First practical use of carbon dioxide was by Joseph Priestley (1733–1804) in the mid-1700s. Priestley found that by dissolving carbon dioxide in water he could produce a fresh, sparkling beverage with a pleasant flavor.
Properties of Carbon Dioxide
• Colorless• Odorless• Non-combustible• Density ~1.5 times
that of air
Pure carbon dioxide gas can be poured because it is heavier than air. (From www.scienceclarified.com)
Properties of Carbon Dioxide• Gas easily converted to solid (dry ice), which
goes directly back to gas phase at atmospheric pressure (sublimates)
Some Uses of Carbon Dioxide
• Carbonated soft drinks• Coolants and refrigerants• Fire extinguishers (especially for electrical and
oil fires, which can not be put out with water)• Retarding food spoilage• Propellant for guns
– BB guns– Paintball guns
• Lasers
Carbon Dioxide and Environment
• Carbon dioxide captures heat radiated from earth’s atmosphere
• Responsible for keeping the planet sufficiently warm to allow life
• Increasing concentrations of carbon dioxide are raising earth’s temperature
• One of the three most important “greenhouse” gasses
Atmospheric Concentrations of CO2
Carbon Dioxide Emissions
CO2 Air Pollution: Asthma
Hypercapnic Disorders: Definitions
Hypercapnia: PaCO2 ≥ 45 mm Hg
Hypercapnic respiratory failure: hypercapnia plus acidosis– Acute: no or minimal metabolic compensation– Chronic: appropriate metabolic compensation
Causes of Hypercapnic Resp. FailureNeural & Neuromuscular• Brain
– Drugs
• Motor neurons• Neuromuscular junction• Respiratory muscles
Chest Wall• Kyphoscoliosis• Ankylosing spondylitis• Flail chest
“Medical” Diseases• COPD• Severe asthma• Late stage interstitial lung
disease• Pulmonary edema• Sleep apnea / obesity-
hypoventilation• Hypothyroidism
Environmental
Iatrogenic
Causes of Hypercapnic Resp. FailureNeural & Neuromuscular• Brain
– Drugs
• Motor neurons• Neuromuscular junction• Respiratory muscles
Chest Wall• Kyphoscoliosis• Ankylosing spondylitis• Flail chest
“Medical” Diseases• COPD• Severe asthma• Late stage interstitial lung
disease• Pulmonary edema• Sleep apnea / obesity-
hypoventilation• Hypothyroidism
Environmental
Iatrogenic
Causes of Hypercapnic Resp. FailureNeural & Neuromuscular• Brain
– Drugs
• Motor neurons• Neuromuscular junction• Respiratory muscles
Chest Wall• Kyphoscoliosis• Ankylosing spondylitis• Flail chest
“Medical” Diseases• COPD• Severe asthma• Late stage interstitial lung
disease• Pulmonary edema• Sleep apnea / obesity-
hypoventilation• Hypothyroidism
Environmental
Iatrogenic
Causes of Hypercapnic Resp. FailureNeural & Neuromuscular
Brain– Drugs
• Motor neurons• Neuromuscular junction• Respiratory muscles
Chest Wall• Kyphoscoliosis• Ankylosing spondylitis• Flail chest
“Medical” Diseases• COPD• Severe asthma• Late stage interstitial lung
disease• Pulmonary edema• Sleep apnea / obesity-
hypoventilation• Hypothyroidism
Environmental
Iatrogenic
Causes of Hypercapnic Resp. FailureNeural & Neuromuscular• Brain
– Drugs
• Motor neurons• Neuromuscular junction• Respiratory muscles
Chest Wall• Kyphoscoliosis• Ankylosing spondylitis• Flail chest
“Medical” Diseases• COPD• Severe asthma• Late stage interstitial lung
disease• Pulmonary edema• Sleep apnea / obesity-
hypoventilation• Hypothyroidism
Environmental – Industrial, Natural
Iatrogenic - Drugs, Ventilators
Causes of Hypercapnic Resp. FailureNeural & Neuromuscular• Brain
– Drugs
• Motor neurons• Neuromuscular junction• Respiratory muscles
Chest Wall• Kyphoscoliosis• Ankylosing spondylitis• Flail chest
“Medical” Diseases• COPD• Severe asthma• Late stage interstitial lung
disease• Pulmonary edema• Sleep apnea / obesity-
hypoventilation• Hypothyroidism
Environmental – Industrial, Natural
Iatrogenic - Drugs, Ventilators
Neuromuscular Causes of Hypercapnic Respiratory Failure
• Skeletal Muscle Diseases– Some (but not all) of the Muscular Dystrophies
• Duchenne muscular dystrophy• Merosin-negative congenital muscular dystrophy• Myotubular myopathy 1 • Autosomal dominant distal myopathy• One of the autosomal recessive limb-girdle
muscular dystrophies– Myotonic Dystrophy– Polymyositis/dematomyositis
Neuromuscular Causes of Hypercapnic Respiratory Failure
• Neuromuscular Junction Disorders– Myasthenia gravis– Lambert Eaton myasthenic syndrome– Botulism– Organophosphate poisoning
• Motor Neuron Disorders– Amyotrophic lateral sclerosis– Guillain-Barre syndrome– Poliomyelitis– Spinal cord injury
Famous People & Motor Neuron Disorders • Guillain Barre
– Joseph Heller, Andy Griffith
• Polio vs Guillain Barre– Franklin D Roosevelt
• Polio– Sports: Jack Nicklaus– Acting/Movies: Alan Alda, Francis Ford Coppola, Mia Farrow– Musicians: Donovan, Joni Mitchell, Itzhak Perlman, David
Sanborn, Neil Young, Dmitri Shostakovich– Other: Arthur Guyton, Arthur C. Clarke
• Amyotrophic lateral sclerosis– Lou Gehrig, Lead Belly, Catfish Hunter– Stephen Hawking may have different type of motoneuron disease
• Spinal cord injury– Christopher Reeve
Most of information from Wikipedia
Iatrogenic Hypercapnia and Mechanical Ventilation
• Study of low vs conventional tidal volume / pressure mechanical ventilation for ARDS
• Much higher incidence of hypercapnia (pCO2 > 50 mm Hg) in low tidal volume / low pressure group
Stewart et al., NEJM 1998
Iatrogenic Hypercapnia and Mechanical Ventilation “Permissive Hypercapnia”• Study of low vs conventional tidal volume / pressure
mechanical ventilation for ARDS• Much higher incidence of hypercapnia (pCO2 > 50 mm
Hg) in low tidal volume / low pressure group
Stewart et al., NEJM 1998
Pickwickian Syndrome
Did Mr. Pickwick have:1. Sleep apnea with hypersomnolence2. Obesity-hypoventilation syndrome3. Both4. Neither
Pickwickian Syndrome
Little boy whowould alwaysfall asleep
Obesity Hypoventilation Syndrome(OHS)
• Definition– BMI > 30 kg/m2
– Awake arterial pCO2 > 45 mm Hg– No other causes for hypercapnia
OHS in Hospitalized Patients• Studied 4332 admissions to medical services• 277 (6%) were severely obese (BMI > 35 kg/m2)• OHS present in 31% with severe obesity
– Mean pCO2 of 52 ± 7 vs 37 ± 6 mm Hg in subjects with simple obesity
• When BMI > 50 kg/m2, prevalence OHS was 48%
Nowbar et al., Am J Med 2004
Dark bars OHS, light bars simple obesity
Outcome Following Discharge• Survival curves for patients with obesity-associated hypoventilation
or simple obesity after discharge from hospital• Adjusted for age, sex, body mass index, electrolyte abnormalities,
renal insufficiency, history of thromboembolism, and history of hypothyroidism.
Now
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Prevalance OHS Among OSA• Obesity hypoventilation syndrome (OHS) among
subjects with obstructive sleep apnea (OSA)– Prevalence of 20-30%
• Predictors of OHS:– Serum bicarbonate level (P < 0.001)– Apnea hypopnea index (P = 0.006)– Lowest oxygen saturation during sleep (P < 0.001)
• Threshold bicarbonate level of 27 mEq/l:– Sensitivity 92%– Specificity 50%
Mokhlesi et al., Sleep Breath, 2007
US President with Probable OSA
He frequently fell asleep "in the middle of the day’s business -- at his desk, at a public affair, or while signing commissions.“ Publicly, he slept at the opera, at funerals, and, "invariably," in church. He fell asleep while playing cards, and while sitting upright in his car, even an open car on Fifth Avenue in New York City. On a cross-country drive "his great bulk would lunge from side to side as the car turned or jolted over street-car tracks and crossings, yet he would never wake.“ He could sleep while standing.
Who is this?
US President with Probable OSA
He frequently fell asleep "in the middle of the day’s business -- at his desk, at a public affair, or while signing commissions.“ Publicly, he slept at the opera, at funerals, and, "invariably," in church. He fell asleep while playing cards, and while sitting upright in his car, even an open car on Fifth Avenue in New York City. On a cross-country drive "his great bulk would lunge from side to side as the car turned or jolted over street-car tracks and crossings, yet he would never wake.“ He could sleep while standing.
Who is this?
US President with Probable OSA
He frequently fell asleep "in the middle of the day’s business -- at his desk, at a public affair, or while signing commissions.“ Publicly, he slept at the opera, at funerals, and, "invariably," in church. He fell asleep while playing cards, and while sitting upright in his car, even an open car on Fifth Avenue in New York City. On a cross-country drive "his great bulk would lunge from side to side as the car turned or jolted over street-car tracks and crossings, yet he would never wake.“ He could sleep while standing.
President Taft
How is this related to hypercapnic respiratory failure?
Lake Nyos, Cameroon
Limnic Eruption of Lake Nyos• Geology
– Deep lake high on an inactive volcano– Pocket of magma lies beneath its waters and leaks
carbon dioxide into the waters– Water in deep layers is supersaturated with carbon
dioxide
• August 1986, the lake released a large cloud of carbon dioxide in a limnic eruption– Deep water layers came to surface, and reduction in
pressure resulted in CO2 release– 1.6 million tons of CO2 were released
• Killed 1,746 people and up to 3,500 livestock– Mainly carbon dioxide, with traces of carbon sulfide,
hydrogen sulfide and sulfur dioxide
Long-Term Sequela from Lake Nyos
• Study compared 381 exposed with 128 non-exposed subjects
• No difference in frequency of dyspnea, cough, sputum
• No difference in peak expiratory flow
Danger of Repeated Episode
• Carbon dioxide levels have built up again to previous levels, so another limnic eruption could occur
• Natural dam holding lake in place is said to be weak, which could release deep supersaturated waters and cause carbon dioxide release
Degassing Lake Nyos
Management of Hypercapnia
• Is it acute or chronic or acute on chronic?• What is the underlying etiology?
• Treatment options
– Specific therapy for underlying cause
– No mechanical ventilation– Non-invasive mechanical ventilation– Invasive mechanical ventilation
Hypercapnic Respiratory FailureEarly Treatment Modalities
Severinghaus et al,Am J Resp Crit Care Med 157: S114-S122, 1998
Polio EpidemicDenmark,1952
Polio -- Iron Lung Ward – 1950’s
Rancho Los Amigos Hospital
Mechanical Ventilation for Acute Hypercapnic Respiratory Failure
• Intubation with conventional mechanical ventilation
• Non-invasive positive pressure ventilation (NPPV)
Selection criteria (at least two should be present)
• Moderate to severe dyspnea with use of accessory muscles and paradoxical abdominal motion
• Moderate to severe acidosis (pH 7.30-7.35) and hypercapnia (PaCO2 45-60 mm Hg)
• Respiratory frequency > 25 breaths/min
Pauwels et al, Am J Resp Crit Care Med 163: 1256, 2001
Criteria for Non-Invasive Ventilation in COPD
Criteria for Non-Invasive Ventilation in COPD
Exclusion criteria (any may be present)• Respiratory arrest• Cardiovascular instability (hypotension,
arrythmias, MI)• Somnolence, impaired mental status,
uncooperative patient• High aspiration risk• Viscous or copious secretions• Recent facial or gastroesophageal surgery• Craniofacial trauma• Fixed nasopharyngeal abnormalities• Extreme obesity
Pauwels et al, Am J Resp Crit Care Med 163: 1256, 2001
Masks for Non-Invasive Ventilation
• Types of mask– Nasal
• More comfortable• Patient can eat• Minimal aspiration risk• Communication easier
– Whole face• No entrainment of room air• May allow better ventilation
• Choice of mask– Hypercapnic respiratory failure
• Nasal mask often sufficient• Sometimes need whole face mask
– Hypoxic respiratory failure• Always need whole face mask
Ventilator Devices for Non-Invasive Ventilation
• Types of Ventilator Devices– BiPAP
• Simple BiPAP – oxygen set by liter flow• Advanced BiPAP – can set FiO2
– Conventional Ventilator
• Choice of Ventilator Device– Hypercapnic respiratory failure
• Simple BiPAP is sufficient• Any of above may be used
– Hypoxic respiratory failure• Need advanced BiPAP or conventional ventilator
Inspiratory and Expiratory Pressures
• Hypercapnic respiratory failure– Inspiratory pressure typically in 12 to 20 cm H2O
range• Lower values better tolerated• Higher values give better ventilation
– Expiratory pressure not really needed• Except: many BiPAP machines require several cm H2O to
function properly
• Hypoxic respiratory failure– Inspiratory pressure typically in 12 to 20 cm H2O
range– Expiratory pressure gradually increased to improve
oxygenation
COPD – Non-Invasive Ventilation
• Total of 85 patients with COPD exacerbation from five hospitals in France, Italy and Spain
• Non-invasive ventilation– Face mask with foam inside to reduce dead space– Pressure support ventilator system with back-up
rate– Inspiratory pressure 20 cm H2O, no expiratory
pressure – Oxygen to achieve saturation > 90%– At least 6 hours/day, up to 22 hours/day if needed
Brochard et al., NEJM 333:817, 1995
COPD – Non-Invasive Ventilation
Non-invasive ventilation signficantly improved PaCO2 and PaO2
Brochard et al., NEJM 333:817, 1995
COPD – Non-Invasive Ventilation
Changes one hour after entry into study: worsening in conventional group vs improvement in non-invasive group
Brochard et al., NEJM 333:817, 1995
COPD – Non-Invasive VentilationOutcomes• Reduced need for intubation
– Non-invasive group 26% intubated (11/43) – Conventional group 74% intubated (31/42) (P <
0.001)
• Reduced complication rate– Non-invasive group 16% (7/43)– Conventional group 48% (20/42) (P = 0.001)
• Improved survival to hospital discharge– Non-invasive group 91% (39/43)– Conventional group 71% (30/42) (P = 0.02)
Brochard et al., NEJM 333:817, 1995
COPD – Non-Invasive Ventilation
Outcomes (cont’d)• Reduced length of stay in hospital
– Non-invasive group 23 ± 17 days – Conventional group 35 ± 33 days (P = 0.02)
• Lower proportion with length of stay > 4 weeks
– Non-invasive group 18% (7/43)
– Conventional group 47% (14/42) (P = 0.004)
Brochard et al., NEJM 333:817, 1995
Meta-Analysis: COPD and Non-Invasive Ventilation
Lightowler et al., BMJ 326:185, 2003
2003
British Medical Journal
Lightowler et al., BMJ 326:185, 2003
Risk of treatment failure (mortality, need for intubation, intolerance)Relative risk 0.51
Meta-Analysis: COPD and Non-Invasive Ventilation
Risk of mortalityRelative risk 0.41
Lightowler et al., BMJ 326:185, 2003
Meta-Analysis: COPD and Non-Invasive Ventilation
Lightowler et al., BMJ 326:185, 2003
Risk of intubationRelative risk 0.42
Meta-Analysis: COPD and Non-Invasive Ventilation
Lightowler et al., BMJ 326:185, 2003
Other significant outcome improvements with non-invasive ventilation in COPD
• Reduced rate of complications• Reduced hospital length of stay• Improved pH, pCO2 and respiratory rate within one
hour of initiation
Meta-Analysis: COPD and Non-Invasive Ventilation
Ventilation for Chronic Hypercapnia• Clear role for chest wall and neuromuscular disease, and
congenital central hypoventilation syndrome• Often used for obesity-hypoventilation with sleep apnea
(ie use BiPAP rather than CPAP)• Controversial for obstructive lung diseases
• For neuromuscular diseases, often able to start with nocturnal only, and then move to 24 hours/day with disease progression
• Non-invasive ventilation generally preferred over invasive ventilation, unless prominent bulbar problems or subject completely dependent on ventilator (eg. high spinal cord injury)
Long-Term Non-Invasive Ventilation and Restrictive Disorders
American College of Chest Physicians Guidelines, 1999
NPPV and Restrictive Disorders
Perrin et al., Muscle Nerve2004
Use of Home Chronic Ventilation
• Prospective 7 year follow up of patients treated at home with nasal positive pressure ventilation
• Two university hospitals and a pulmonary rehabilitation center
• Mean 6.9 hours of ventilation per 24 hours
Ventilator Modality
Blood Gas Changes
Survival: 7 Year Follow Up
Examples of People Undergoing Long Term Mechanical Ventilation
Christopher Reeve Stephen Hawking1995 to 2004 ~1985 to present
Long-Term Ventilation Not for Everyone
Morris Schwartz, Ph.D., Professor of Sociology, Brandeis University
The End