A 76-year-old man is admitted after falling down four steps at home. He weighs 75 kg. He has fractures of the left fifth to eighth ribs and it hurts him to breathe in. He is alert and takes rapid shallow breaths, refusing to breathe deeply. Respiratory rate is 30/min and a bedside spirometer records a tidal volume of 250 mL. Blood pressure is 140/80 mmHg and pulse 94/min. He is breathing room air.
Which one of the following acid-base patterns would his arterial blood gas analysis be expected to show?