When should a patient with chronic obstructive pulmonary disease (COPD) be intubated in the intensive care unit (ICU)?

When to Intubate a COPD Patient in the ICU

Intubate immediately if the patient has imminent respiratory arrest, gasping respiration, pH <7.15 despite initial resuscitation, severe respiratory distress, depressed consciousness (GCS <8), or signs of low cardiac output. 1

Immediate Intubation Criteria

The following situations mandate immediate consideration for invasive mechanical ventilation without delay:

• Respiratory arrest or gasping respirations - These are absolute indications requiring immediate airway control 1
• Severe acidosis with pH <7.15 - This threshold indicates IMV is necessary following initial resuscitation and controlled oxygen therapy 1
• Depressed consciousness (Glasgow Coma Score <8) - Inability to protect the airway mandates intubation 1
• Signs of low cardiac output - Hemodynamic instability requires immediate intubation 1
• Severe respiratory distress - Overwhelming work of breathing that cannot be supported by NIV 1

NIV Failure Requiring Intubation

Non-invasive ventilation (NIV) should be attempted first in most COPD exacerbations with acute respiratory failure, but you must recognize failure early and intubate promptly to avoid increased mortality. 1

Criteria for NIV Failure:

• Worsening pH or lack of improvement within 1-2 hours of NIV initiation 2, 3
• Persisting or deteriorating acidosis despite optimized NIV settings 1
• Deterioration in pH despite NIV - Any worsening trend mandates intubation 1
• Lack of improvement in arterial blood gases after 4-6 hours of NIV 2
• Increasing respiratory distress despite NIV support 2
• Deteriorating mental status on NIV 2

Critical Timing Consideration:

Delaying intubation when NIV is clearly failing increases mortality - this is evidenced by post-extubation respiratory failure data showing that delay in re-intubation caused by persisting with ineffective NIV increased mortality. 1, 2

pH-Based Decision Algorithm

While absolute values should not be used in isolation, pH provides important guidance:

• pH <7.25 - Consider IMV and prepare for possible intubation 1
• pH <7.15 - IMV is indicated (following initial resuscitation and controlled oxygen) 1
• pH >7.26 - Better predictor of survival; NIV more likely to succeed 1

Important caveat: There is insufficient evidence to support absolute pH or PaCO2 values as sole intubation criteria, as no single value applies to all patients in all situations. 1

Contraindications to NIV (Direct Intubation Indicated)

The following patients should proceed directly to intubation rather than attempting NIV:

• Cardiovascular instability 2
• Copious or viscous secretions with high aspiration risk 2
• Inability to cooperate or protect airway 2
• Recent facial or gastroesophageal surgery 2
• Fixed nasopharyngeal abnormality 2

Before Declaring NIV Failure - Technical Checklist

Before considering NIV to have failed, verify that common technical issues have been addressed and ventilator settings are optimal. 1

Check for:

• Mask leak - Minimize by adjustment or changing mask type 1
• Positional upper airway obstruction - Ensure head flexion is avoided 1
• Patient-ventilator asynchrony - May be caused by insufficient/excessive IPAP, inappropriate Ti/Te settings, high intrinsic PEEP, or excessively sensitive triggers 1

Critical Pitfalls to Avoid

• Over-oxygenation: Target SpO2 88-92% only; excessive oxygen worsens hypercapnia and can increase mortality by 58% overall and 78% in COPD patients 4, 2
• Therapeutic nihilism: UK data shows only a small proportion of NIV patients escalate to IMV despite data suggesting more should; COPD patients have better ICU survival than most other medical causes requiring invasive ventilation 1
• Persisting with ineffective NIV: This adds to patient discomfort and risks cardiorespiratory arrest 1
• Using PaCO2 alone: pH is a better predictor of survival than PaCO2 during acute episodes 1, 2

Prognostic Considerations Supporting Intubation

Do not withhold intubation based on misconceptions about poor outcomes - the evidence shows:

• Duration of ICU stay and survival in AECOPD is better than most other medical causes for which invasive ventilation is employed 1
• Five-year outcome after respiratory failure is better than many doctors appreciate and does not depend on acute PaCO2 level 1
• Mean survival of patients who were hypercapnic on admission but later became normocapnic was 2.9 years 1
• Clinicians' estimated prognosis for AECOPD patients was lower than indicated by predictive modeling 1

Factors Favoring Intubation Decision

• Demonstrable remedial reason for decline (e.g., pneumonia, drug overdose) 1
• First episode of respiratory failure 1
• Acceptable quality of life or habitual activity level prior to admission 1

Factors That May Discourage Intubation

• Previously documented severe COPD unresponsive to maximal therapy 1
• Poor quality of life (e.g., housebound despite maximal therapy) 1
• Severe comorbidities (e.g., pulmonary edema, neoplasia) 1
• Patient's documented wishes (e.g., living will) 1

The decision to institute or withhold ventilatory support must be made by a senior clinician with complete information about the patient's premorbid state and wishes. 1