MSFinals-0873

MSFinals-0873

A known case of chronic obstructive pulmonary disease (COPD) presents to the Emergency department, distressed and cyanosed. Arterial blood gases reveal pH 7.2 (7.36-7.44), PaO2 8.3 kPa (11.3-12.6 kPa), PaCO2 10 kPa (4.7-6.0 kPa). The patient, who is in his 60s, is given high concentration oxygen together with a salbutamol nebuliser and intravenous hydrocortisone. Despite these interventions, the patient’s breathing effort worsens, although pulse oximetry showed SaO2 of 93%. What could be the reason for the patient’s deterioration?