The most appropriate next step in management is intubation and mechanical ventilation. This patient is experiencing an exacerbation of his COPD with hypercapnic respiratory failure with hypoxia and mental status changes. Although the majority of patients with acute exacerbation of COPD should undergo a trial of noninvasive ventilation (NIV) and reevaluation prior to intubation and mechanical ventilation, encephalopathy that impairs the ability to cooperate with NIV or manage secretions is a contraindication to NIV. Other contraindications to NIV include conditions that make airway protection difficult (for example, bulbar dysfunction or ineffective gag or cough reflexes), medical instability (such as hemodynamic instability, severe acidosis, arrhythmias, or active upper gastrointestinal bleeding), and mechanical issues associated with NIV (including upper airway obstruction, recent facial trauma or surgery, or esophageal or transsphenoidal surgery). Because this patient would likely not be able to adhere with NIV because of confusion and may not be able to protect his airway, intubation and mechanical ventilation are indicated.

Although increasing the level of inspired oxygen to maintain an oxygen saturation of greater than 90% in acute COPD exacerbations has been shown to be beneficial, doing so would not address this patient's hypercapnia and associated mental status changes, which need to be treated with ventilatory support.

The use of NIV in eligible patients is effective and can avoid intubation in several disease states, particularly with COPD exacerbations or decompensated heart failure. In COPD, NIV has been shown to decrease the need for intubation, decrease mortality, and reduce length of hospital stay and complication rates. Compared with invasive mechanical ventilation, NIV uses pressure instead of volume to assist ventilation, and multiple different modes are available for use with limited data regarding the effectiveness of one mode of ventilation relative to another. However, none of the NIV modes would be appropriate in this patient with a contraindication to this therapy.