A 55-year-old male with a history of diabetes mellitus underwent an uncomplicated hemorrhoidectomy under general anesthesia. No Foley catheter was placed. In the postanesthesia care unit, he complained of pain and was given IV narcotics.
The patient is admitted for observation. Six hours postoperatively, the floor nurse calls because the patient reports the urge to void but despite numerous attempts has been unable to do so. He is hemodynamically stable and mentating well, but does have distention and tenderness to palpation in the suprapubic area.
1. What additional history or physical examination findings would be useful in this patient? What are the most common risk factors for postoperative urinary retention (POUR)?
2. What are the most common etiologies of POUR? Which is most likely in this patient?
Postoperative Urinary Retention
POUR is a common complication resulting in numerous pages to the PGY-1 on service. The process of socially appropriate voiding requires frontal cortex coordination with the pontine micturition center to control the spinal reflex arcs manipulating the delicate balance between the promicturition parasympathetic drive and the antimicturition sympathetic drive. The desire to void should normally present with 150 cm3 of urine, with normal bladder capacity ranging between 400 and 600 cm3. A clinical examination with a palpable bladder and dullness to percussion along with symptoms of lower abdominal discomfort are classic signs of POUR; however, a bedside bladder ultrasound should be obtained whenever possible to support clinical findings and estimate the degree of bladder distension.
Based on common risk factors, it is possible for the astute PGY-1 to anticipate which patients are likely to suffer from POUR. Risk factors include the following:
- BPH or prior history of POUR
- Age 50 years or more
- Male gender
- Neuropathy or neurologic disorders
One can also stratify risk of POUR by type of procedure being undergone, anesthesia used, and postoperative analgesia delivered. Anorectal procedures are known for having a particularly high incidence of POUR, with studies demonstrating frequency of POUR after anorectal surgery to range between 16% and 50%, followed closely by inguinal herniorrhaphy. Spinal anesthesia, epidural anesthesia, and general anesthesia have higher incidences of POUR than local anesthesia. Opioid-based patient-controlled analgesia (PCA) has a slightly higher incidence of POUR compared with oral or IV push opioids due to the more constant inhibition of parasympathetic drives.
The duration of the procedure indirectly increases the likelihood of POUR by dose-dependent effects of anesthetic/analgesic agents. The volume of IV fluids received intraoperatively in the absence of a Foley catheter can also affect POUR as higher volumes may lead to overdistention of the bladder with possible subsequent cystopathy.
Etiologies of POUR are broken down into 3 major categories:
- Drug effect
- Neurogenic (increased sympathetic activity)
The most common of these categories encountered in the surgical patient tends to ...