Delirium screening starts in the PACU

Why it matters

Delirium after surgery is diagnosed late because it is looked for late, and it is looked for late because screening has been treated as a ward activity. The 2024 European Society of Anaesthesiology and Intensive Care guideline moves the start line: postoperative delirium, defined per DSM-5, is to be measured with a validated screening tool at least once daily for at least three days, starting in the recovery room or PACU on the day of surgery, or at latest on postoperative day 1 aldecoa-2024. That sentence puts the first screen inside the PACU.

The consequence of getting this wrong is the quiet patient. The form of delirium that is easiest to miss is the one that does not disturb anyone, and a screen applied only when someone is disturbed will not find it.

Mechanism

The mechanism of postoperative delirium is not settled, and the status chip on this page says so. Candidate contributions include neuroinflammation triggered by surgical injury, disruption of neurotransmission by anaesthetic and sedative drugs, disturbed sleep and circadian rhythm, pain and its treatment, and the metabolic derangements of the perioperative period acting on a brain with reduced reserve. What is settled is the clinical shape: an acute disturbance of attention and awareness that fluctuates, which is why a single observation at one time of day can miss it and why the guideline specifies a validated tool applied repeatedly.

Evidence

The 2024 ESAIC guideline defines postoperative delirium per DSM-5 and requires that it be measured with a validated screening tool at least once daily for at least three days, starting in the recovery room or PACU on the day of surgery, or at latest on postoperative day 1 aldecoa-2024. It contains 13 recommendations, states that the certainty of evidence across them ranges from very low to moderate, and searched the literature from 1 April 2015 to 28 February 2022 aldecoa-2024.

It supersedes the 2017 ESAIC guideline, which is cited on this site only to show what the update changed aldecoa-2017.

What this does not show

The guideline rests on a large randomised literature for prevention. It does not rest on trials for the claim that emergence agitation and postoperative delirium are different entities with different time courses, or for the claim that the hypoactive form is both commoner and more often missed; those are descriptive epidemiology and screening-performance claims, and the guideline’s own certainty of evidence is very low to moderate aldecoa-2024. This day is therefore tagged as resting on a guideline, with the prevention material understood as the trial-based portion.

The rule the director’s content list places here, that hypoxaemia, hypoglycaemia and pain must be excluded before either the delirium or the emergence-agitation label is applied, is likely in the guideline but has not been verified against its text: [TODO_VERIFY: the 2024 ESAIC wording on excluding hypoxaemia, hypoglycaemia and pain before labelling delirium or agitation.]

Paediatric emergence delirium after sevoflurane is on the content list for this day and has no ledger row: [NUMBER NEEDED: incidence of emergence delirium after sevoflurane in children and the validated scale used to score it].

Dexmedetomidine, if any delirium page comes to recommend it, carries a European regulatory warning about mortality in intensive care patients aged 65 or younger; a parallel US action has not been confirmed: [TODO_VERIFY: current US labelling for dexmedetomidine before any delirium or agitation page recommends it.]

At the bedside

Screen in the PACU, with the validated tool your institution has adopted, and record the result; the guideline’s start line is the day of surgery, not the ward round the next morning aldecoa-2024. [PRACTICE VARIES: the screening tool used, who applies it, and how the result is recorded differ between institutions.]

Before you label a patient delirious or agitated, look for what else could produce an inattentive or restless patient in the first hours after surgery, and treat what you find. The exclusion rule awaits verification against the guideline text, but the reasoning behind it is the reasoning of every other day on this site: explain the sign before you name it.

Hold the guideline’s recommendations with the firmness its own grading allows. Very low to moderate certainty is a reason to screen, because the cost of screening is low, and a reason to be modest about what any single preventive measure will achieve aldecoa-2024.

Check yourself

Three items. Every option carries an explanation. Progress is not saved.