A 68-year-old man is 8 hours post total knee replacement. He… | MyMerci
Medical Emergencies PA
Question

A 68-year-old man is 8 hours post total knee replacement. He received intrathecal morphine plus IV morphine PRN. He has not voided since surgery, reports lower abdominal fullness and pressure, and the lower abdomen is tender and bulging on palpation. He denies severe pain. Which is the priority nursing action?

Explanation
Opioid-induced urinary retention is common, especially in older men with prostatic hypertrophy and after intrathecal or epidural opioids. Mechanism: mu-receptor activation increases bladder sphincter tone and decreases detrusor contraction. Untreated retention causes overdistension, decreased detrusor recovery, urinary tract infection, and acute kidney injury. Standard nursing approach: (1) assess voiding pattern (last void time, volume), abdominal exam, and patient report — bladder fullness, pelvic pressure, restlessness; (2) bladder scan is the noninvasive standard — over 400 mL postvoid or no void is significant; (3) try noninvasive measures first — privacy, listening to running water, warm pack to suprapubic area, peri-care, ambulation if allowed, hand in warm water; (4) straight (in-and-out) catheterization is preferred over Foley to avoid CAUTI and allow bladder recovery; (5) if recurrent or persistent, notify the prescriber for diagnostic eval, opioid rotation to a less retention-causing agent (fentanyl), addition of PAMORA, or short-term Foley with bladder training. Routine reassurance, additional opioid (worsens retention), or immediate Foley without scanning miss the standard noninvasive-first algorithm.

In-depth explanation

Bladder scan first, then noninvasive measures, then straight catheterization, then prescriber notification. Avoid Foley unless necessary because of CAUTI risk.
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For study reference only. Always follow current clinical guidelines and your institution’s protocols.