Psychiatrycommon
A 58-year-old man is on the second postoperative day after an elective right hemicolectomy. Overnight he became restless and drenched with sweat; this morning his hands are coarsely tremulous, he plucks at the bedclothes and he says there are insects crawling on the wall. Temperature 37.5 degrees Celsius, pulse 116/min, blood pressure 162/98 mmHg. His abdomen is soft, the wound is clean and the drain is dry. His chart shows oxycodone, hyoscine butylbromide and enoxaparin. At the preadmission clinic he described himself as a social drinker. Which one of the following best explains this morning's state?