Voiding and drinking are habits, not discharge criteria

Why it matters

Every PACU has discharge rituals, and the two most durable are the drink and the void. The 2013 ASA practice guideline for postanesthetic care, Section V, Protocol for Discharge, states that the literature is insufficient to evaluate the benefits of requiring patients to urinate before discharge asa-pacu-2013. What sits beside that statement is not an evidence grade but an opinion survey, and the survey went the other way from the convention: 85% of surveyed members supported not requiring voiding before discharge, and requiring patients to drink water before discharge appears among the interventions members did not support asa-pacu-2013.

The consequence of getting this wrong is a patient held in the PACU, or a bed held from the next patient, for a criterion nobody can source.

Mechanism

The rituals have a physiological rationale, which is why they persist. Neuraxial anaesthesia and opioids impair detrusor function and the sensation of bladder fullness, so retention after discharge is a real risk, and a void before leaving was the proxy for a working bladder. Nausea after anaesthesia is real, and tolerating fluid was the proxy for a settled gut. The mechanism explains the habit; it does not establish that applying the proxy to every patient changes anything, and the guideline finds that the literature cannot say it does.

Evidence

The guideline’s evidentiary statement is the sentence the day is built on: the literature is insufficient to evaluate the benefits of requiring that patients urinate before discharge asa-pacu-2013. The member survey reported alongside it records support for not requiring voiding before discharge at 85%, for requiring a responsible individual to accompany the patient home at 95%, and for not requiring a mandatory minimum stay in recovery at 85% asa-pacu-2013. Requiring that patients drink water before discharge is listed among the interventions members did not support asa-pacu-2013.

On urine output more generally, the guideline states that the original literature indicated that assessment of urine output is effective in identifying patients with urinary retention, Category B3-B evidence, that new literature is insufficient to further evaluate that finding, and that assessment of urine output and voiding should be done on a case-by-case basis for selected patients or selected procedures asa-pacu-2013.

So the teaching structure is: the guideline declines to endorse the convention, a majority of surveyed members actively favour dropping it, and case-by-case assessment for selected patients is what replaces it asa-pacu-2013.

What this does not show

This day has one ledger row. That is sufficient, because the source is the entire argument, but it means the day cannot say anything the guideline does not. The guideline is thirteen years old and no successor practice guideline has been found; confirm that before asserting it is current asa-pacu-2013.

The guideline is also not the whole picture. The ASA Standards for Postanesthesia Care were amended in October 2024, and their discharge standard assigns the discharge decision to a physician using approved criteria without specifying what those criteria contain; that document has no ledger row yet: [TODO_VERIFY: ASA Standards for Postanesthesia Care as amended 23 October 2024, Standard V, wording and a ledger row.] Until it does, this page can say that the obligation to discharge against approved criteria is real, and cannot quote it.

The discharge instruments the director’s content list expects here are not in the held sources: [NUMBER NEEDED: modified Aldrete score items and discharge threshold] [NUMBER NEEDED: Post-Anaesthetic Discharge Scoring System items and threshold] [NUMBER NEEDED: fast-track bypass criteria]. Nor is the comparison the list asks for: [NUMBER NEEDED: ambulatory discharge criteria and retention risk after neuraxial versus peripheral nerve block].

At the bedside

Know which of your PACU’s discharge criteria are sourced and which are habit. The escort is sourced by survey at 95%; the drink and the void are not asa-pacu-2013. [PRACTICE VARIES: whether voiding is required before discharge, and for whom, differs between institutions and after neuraxial anaesthesia in particular; follow local protocol and be able to say what it rests on.]

Assess the bladder case by case, in the patients and after the procedures where retention is likely, because that is what the guideline replaces the blanket rule with asa-pacu-2013.

Write the discharge against the criteria your institution has approved, and know who is accountable for the decision, because the obligation is current even where its content is not specified.

Check yourself

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