What is the best approach for a patient with severe respiratory acidosis and a DNR (Do Not Resuscitate) status?

Management of Severe Respiratory Acidosis in a DNR Patient

For a patient with severe respiratory acidosis (pH 7.06, PCO2 146) and DNR status, non-invasive ventilation (NIV) is strongly recommended as the primary intervention to improve respiratory status and reduce mortality while respecting the DNR order.

Initial Assessment and Management

• Confirm respiratory acidosis with arterial blood gas analysis (pH 7.06, PCO2 146 mmHg indicates severe respiratory acidosis)
• Identify the underlying cause (COPD exacerbation, pulmonary edema, neuromuscular disorder, etc.)
• Clarify the specific limitations of the DNR order (many DNR orders allow for NIV but not intubation)
• Target oxygen saturation of 88-92% with controlled oxygen therapy 1, 2

Non-Invasive Ventilation Approach

Indications

• Severe respiratory acidosis (pH 7.06) is a strong indication for NIV 1
• There is no lower limit of pH below which a trial of NIV is inappropriate 1

Implementation

1. Use bilevel positive airway pressure (BiPAP) with:

   • CPAP of 4-8 cmH2O
   • Pressure support of 10-15 cmH2O 2

2. Monitor response closely:

   • Repeat ABG after 1-2 hours of NIV 1
   • Look for improvement in pH, PCO2, and respiratory rate
   • Continue NIV for as much time as possible in the first 24 hours if showing benefit 1

3. NIV settings should be adjusted based on:

   • Patient comfort
   • Respiratory rate
   • Chest wall movement
   • Arterial blood gases 1

Special Considerations for DNR Patients

• DNR status does not preclude the use of NIV as a therapeutic intervention 1
• Advanced age alone should not preclude a trial of NIV 1
• Document clear goals of care and parameters for continuation or withdrawal of NIV
• Ensure the patient and family understand that NIV is being used as active treatment, not just for comfort

Monitoring and Follow-up

• Monitor arterial blood gases every 1-2 hours initially, then every 4-6 hours as the patient stabilizes 1
• Assess for clinical improvement (decreased respiratory rate, improved mental status)
• Continue NIV until normalization of pH and PCO2 < 6.5 kPa (48.8 mmHg) 2

Potential Complications to Monitor

• Rapid correction of severe respiratory acidosis can lead to life-threatening hypokalemia - monitor potassium levels closely 3
• Watch for mask-related complications (skin breakdown, claustrophobia)
• Monitor for gastric distension and aspiration risk

If NIV Fails

• Reassess goals of care with patient/family
• Consider palliative measures for symptom control if NIV is unsuccessful
• Avoid aggressive fluid resuscitation which may worsen respiratory status
• Consider opioids for dyspnea management while respecting the DNR order

Prognosis

NIV has been shown to decrease mortality (RR 0.63,95% CI 0.46-0.87) and decrease the need for intubation (RR 0.41,95% CI 0.33-0.52) in patients with acute hypercapnic respiratory failure 1. Even in severe acidosis, a trial of NIV is appropriate and potentially beneficial.