A 58-year-old man with known COPD and diabetes mellitus has been urgently hospitalized for a high fever, cough with massive purulent sputum, dyspnea, and cyanosis. Arterial blood gas result parameters: pO₂ = 51 mmHg, pCO₂ = 54 mmHg, pH = 7.26, standard bicarbonate = 32 mmol/liter.