emDOCs Podcast – Episode 130: Interstitial Lung Disease Part 2

What is the management of AE-ILD?

• First step: provide respiratory support and resuscitate, while excluding other causes of respiratory distress.
• If patient has known ILD, consult pulmonologist or critical care specialist. If they have an exacerbation of ILD, attempt to transfer to center with ECMO and lung transplant capabilities.

Are there any medication considerations?

• Stop any medication associated with worsening ILD.
• Steroids may be beneficial.
  • International guidelines make a weak recommendation for steroids in AE-ILD.
  • Limited data with no high quality RCTs. Steroids do not appear to help in IPF, but most studies demonstrate steroids benefit in exacerbations associated with other subtypes of ILD.
  • One of the more common regimens is methylprednisolone 125 mg daily for 3 days, followed by transition to oral steroids with a taper over 2-4 weeks.
• Initiate antibiotics: azithromycin + 3^rd generation cephalosporin + TMP-SMX for Pneumocystis jirovecii coverage
• Other immunosuppressant agents: azathioprine, mycophenolate mofetil, cyclophosphamide, rituximab, and calcineurin inhibitors (e.g., cyclosporine A and tacrolimus)
  • Limited high-quality data for these.
  • International guidelines recommend treatment with immunosuppressants.
  • Not for ED use but may be administered in the ICU.

What is recommended concerning fluid resuscitation in AE-ILD?

• Goal is net-neutral or net-negative fluid balance.
• Volume overload increases mortality; if clinically hypovolemic or dehydrated and hemodynamically unstable, administer a fluid bolus of 5-10 mL/kg and reassess.

How do you manage the hypoxia and respiratory distress?

• Most cases with AE-ILD have ventilation/perfusion mismatch with hypoxemia
• Supplemental oxygen and respiratory support essential.
• Start with conventional oxygen therapy like nasal cannula, but may need higher oxygen flow rates and support: noninvasive ventilation (NIPPV) including HFNC and BPAP.
  • Optimizing oxygenation and work of breathing with NIPPV early in AE-ILD may improve survival.
  • One study found both HFNC and NIPPV reduced short-term mortality when compared to conventional oxygen therapy with no difference when NIPPV and HFNC were compared. Patients improving with NIPPV had reduced mortality and need for ETI, but those who fail NIPPV have high mortality (whether or not they are intubated).
• HFNC: studies suggest benefit in patients not initially improving with conventional supplemental oxygen; may reduce mortality in those persistently hypoxic despite conventional oxygen therapy.
• If no improvement with HFNC, start BPAP.

What happens if the patient fails NIPPV and intubation is necessary?

• Guidelines and reviews warn against intubating patients with progressive ILD.
  • Mortality for intubated patients ranges between 50-90% due to many issues including ventilator induced lung injury.
  • Mortality also based on specific cause of the ILD. IPF associated with worse outcome
• Key: attempt to optimize with HFNC or BPAP. If they fail NIV, have an honest discussion about the goals of care.
• Patients who benefit most from intubation include those with superimposed cause of respiratory failure that is treatable like an infection or pleural effusion.

What are the recommended ventilator settings for intubated patients?

• Use a lung protective strategy, but this is challenging.
• Patients have stiff, fibrotic lungs that are susceptible to barotrauma and ventilator induced lung injury (VILI); the alveolar collapse and consolidation in ILD can cause permanent derecruitment that does not respond to PEEP and worsening respiratory mechanics (spared areas are overdistended and no recruitment of collapsed areas).
  • Several studies suggest that higher levels of PEEP and lower PaO₂/FiO₂ ratios are associated with higher mortality rates.
  • Target tidal volumes of 6 mL/kg of predicted body weight, plateau pressures < 30 cm H₂O, and PEEP 4-6 cm H₂^85,86
• Ventilator-patient dyssynchrony can also lead to VILI; optimize sedation, and neuromuscular blockade or prone positioning may be necessary.
• Approximately 30% have concomitant pulmonary hypertension and RV dysfunction.
  • Hypoxemia in these patients further worsens pulmonary vasoconstriction and increases right ventricular afterload.
  • May require inhaled pulmonary vasodilators.

What are those other end stage treatments?

• ECMO; indications include severe hypoxia, acidosis, and hypercapnia despite aggressive ventilatory strategies.
  • May also be used before IMV in hypoxic patients despite NIPPV or HFNC, which can prevent VILI and other complications like ventilator-associated pneumonia associated with IMV.
• Lung transplantation is a treatment option for severe, progressive ILD and respiratory failure refractory to other therapies.
• For severe ILD exacerbation, try to transfer to a center where ECMO and lung transplant capabilities.

Summary:

• ILD is a chronic disease with restrictive lung physiology; exacerbations are common and associated with severe morbidity and mortality.
• Consult pulmonology and critical care.
• For AE-ILD, exclude other conditions, provide respiratory support, and resuscitate.
• Administer steroids, IV antibiotics, supplemental oxygen, and for those presenting with ARF, HFNC and NIPPV.
• Reserve IV fluids for clinically hypovolemic or hemodynamically unstable patients.
• Attempt to optimize with HFNC or NIPPV, but if they fail, intubation is necessary.
• Discuss goals of care prior to intubation.
• Use lung protective ventilation for mechanically ventilated patients.
• ECMO and lung transplantation are end stage treatments.