Respiratory Care Management of COPD Exacerbations

Abstract

A COPD exacerbation is characterized by an increase in symptoms such as dyspnea, cough, and sputum production that worsens over a period of 2 weeks. Exacerbations are common. Respiratory therapists and physicians in an acute care setting often treat these patients. Targeted O₂ therapy improves outcomes and should be titrated to an S_pO2 of 88-92%. Arterial blood gases remain the standard approach to assessing gas exchange in patients with COPD exacerbation. The limitations of arterial blood gas surrogates (pulse oximetry, capnography, transcutaneous monitoring, peripheral venous blood gases) should be appreciated so that they can be used wisely. Inhaled short-acting bronchodilators can be provided by nebulizer (jet or mesh), pressurized metered-dose inhaler (pMDI), pMDI with spacer or valved holding chamber, soft mist inhaler, or dry powder inhaler. The available evidence for the use of heliox for COPD exacerbation is weak. Noninvasive ventilation (NIV) is standard therapy for patients who present with COPD exacerbation and is supported by clinical practice guidelines. Robust high-level evidence with patient important outcomes is lacking for the use of high-flow nasal cannula in patients with COPD exacerbation. Management of auto-PEEP is the priority in mechanically ventilated patients with COPD. This is achieved by reducing airway resistance and decreasing minute ventilation. Trigger asynchrony and cycle asynchrony are addressed to improve patient-ventilator interaction. Patients with COPD should be extubated to NIV. Additional high-level evidence is needed before widespread use of extracorporeal CO₂ removal. Care coordination can improve the effectiveness of care for patients with COPD exacerbation. Evidence-based practices improve outcomes in patients with COPD exacerbation.

Keywords: COPD; aerosol therapy; auto-PEEP; care coordination; exacerbation; extracorporeal CO2 removal; high-flow nasal cannula; noninvasive ventilation; oxygen therapy.

Fig. 1.

Categorization of the severity of COPD based on exacerbation history and symptoms according to the 2023 Global Initiative for Chronic Obstructive Lung Disease report. mMRC = Modified Medical Research Council dyspnea scale; CAT = COPD Assessment Test.

Fig. 2.

A: Jet nebulizer to mask for noninvasive ventilation (NIV). B: Mesh nebulizer incorporated into mask for NIV. C: Pressurized metered-dose inhaler with spacer to mask for NIV. B from reference 65.

Fig. 3.

Airway pressure and flow waveforms. Note the large difference in peak inspiratory pressure and plateau pressure (P_plat) in the presence of high airways resistance. Also note the P_plat is affected by the level of auto-PEEP. Adapted from reference 81. PIP = peak inspiratory pressure. P_plat = plateau pressure.

Fig. 4.

Auto-PEEP is measured using an end-expiratory pause. If the patient is actively exhaling, pressure increases during the breath-hold, as indicated by the dashed line; this invalidates the measurement of auto-PEEP. Adapted from reference 81. PIP = peak inspiratory pressure.

Fig. 5.

The auto-PEEP measured at the proximal airway is less than the auto-PEEP in some lung regions if airways collapse during exhalation. Adapted from reference 81.

Fig. 6.

Airway pressure, flow, volume, and esophageal pressure (P_es) waveforms in a patient with auto-PEEP. Note the decrease in P_es required to trigger the ventilator, which represents the amount of auto-PEEP. Also note that flow does not return to zero at the end of exhalation, and the inspiratory effort does not trigger the ventilator. Adapted from reference 81. P_aw = airway pressure; P_es = esophageal pressure.

Fig. 7.

Flow, airway pressure, and esophageal pressure in a patient with severe COPD. The arrows represent ineffective efforts. Adapted from reference 81.

Fig. 8.

Effect of PEEP, auto-PEEP, and trigger effort in the setting of flow limitation. Adapted from reference 81.

Fig. 9.

Effect of increased intra-abdominal pressure on expiratory flow in a patient with expiratory flow limitation. Note that there is no change in expiratory flow as intra-abdominal (and hence intrathoracic) pressure increases. Adapted from reference 81.

Fig. 10.

In the top graphic, a patient with COPD has an auto-PEEP of 10 cm H₂O. When the PEEP is increased to 8 cm H₂O, there is no change in peak inspiratory pressure and plateau pressure, consistent with flow limitation.

Fig. 11.

Pressure support ventilation with the cycle criteria set a 10, 25, and 50%. With a higher cycle criterion, note that the inspiratory time is shorter. The higher cycle criteria are appropriate for patients with COPD. Adapted from reference 81.