Why Do I Have Urinary Bladder Retention After General Anesthesia?
You can't go home until you pee.— Hospital recovery room staff around the world
Urinating may seem like a simple enough condition to meet before leaving the hospital. Many people, however, find it difficult to empty their bladder after surgery. This frustrating condition is called POUR, post-operative urinary retention, and it is one of the most common side-effects of general anesthesia. It usually resolves with minor interventions, but some cases may result in over-distended bladders, urinary tract infections, and hospital admissions.
Up to 70 percent of patients have minor trouble urinating after surgery. One in 20 people experience more significant bladder retention problems. Find out more here whether you may be at risk of experiencing POUR after surgery and some strategies to discuss with your doctor.
Trouble Urinating After Surgery
General anesthesia becomes safer with each passing decade. The medicines used to put a patient under do, however, change how your body works. General anesthesia drugs affect brain function and inhibits the autonomic (involuntary) nervous system that triggers urination. The result is that the detrusor (bladder muscle) contractions are suppressed or decreased. This is an effect of both IV agents and gases used during general anesthesia.
Am I at Risk of Experiencing Urinary Retention?
If you meet most of these criteria, you may be at risk of experiencing urinary retention. Ask your doctor before surgery about whether the medications you are taking (or will take) put you at higher risk.
- Over 50 years of age.
- Male (especially with preexisting enlarged prostate).
- Lengthy surgery and anesthesia time.
- Undergoing pelvic or hernia repair surgery.
- Increased administration of IV fluid (over-stretching the bladder makes it harder to empty after general anesthesia).
- Many types of medications taken or given before, during, or after surgery (beta-blockers, for example).
Managing Urinary Retention During and After Anesthetic
If you have a surgery scheduled and are concerned about urinary retention, talk to your doctor. Be sure to discuss the importance of complete urination before the operation and ask whether any of these strategies may be appropriate for you:
- Bladder ultrasound during surgery. This technique may help operating-room staff monitor whether your bladder is reaching capacity.
- Movement after surgery. Sitting up, standing, and walking as soon as is safe after your operation may help stimulate urination.
- Medication. There are drugs available to counteract the effects of anesthesia on the area of the brain that controls urination.
Healthy Bladder Function After Anesthesia
A healthy bladder is a fairly complex, sac-like organ. Composed of a body and a neck, the bladder is made of different types of muscle fibers and nerves that interact to allow micturition, or the passage of urine. Emptying the bladder requires input and action from the bladder, surrounding muscles, spinal cord, brainstem, and brain.
The bladder's body holds the urine. There are stretch receptors in the walls of the bladder body that indicate the level of fullness of the bladder. These special sensors send signals to the brain when the bladder should be emptied. The neck of the bladder has sphincters or valves that open to allow urine to be expelled.
- The internal urethral sphincter, located inside the neck of the bladder, is made of smooth muscle fibers and is not under voluntary control.
- The external urethral sphincter is a ring formed by the pelvic floor muscles (striated muscle) and is under voluntary control.
Emptying the bladder is both voluntary and involuntary. Spinal reflex pathways control urination under the regulation of higher centers in the brain. The brainstem contains a “storage” center and a “micturation” center (pontine storage center and pontine micturation center) that feed information to the spinal pathways that in turn send signals to the bladder.
When the bladder needs to be emptied, the body of the bladder contracts. Then the internal sphincter relaxes, due to input from the parasympathetic nervous system (part of the involuntary nervous system). The brain tells the external sphincter muscles to relax (the voluntary part of the process) and the urine exits through the urethra.
Complications Related to Urinary Retention
More than just an annoyance, bladder retention after general anesthesia can lead to significant consequences.
- Prolonged retention of urine has been linked to urinary tract infections. An overfull bladder is more likely to be incompletely emptied, which is a risk factor for infection. Also, if a catheter has to be used to relieve the retention, this increases the risk of infection, as well.
- Longer-term issues with bladder emptying is another risk. There is some evidence that having an over-distended bladder can cause difficulty in emptying the bladder even after leaving the hospital.
- A stretched bladder signals the nerves of the parasympathetic nervous system, which can affect other organs with parasympathetic nerves. This can result in slowed or irregular heartbeat, low or high blood pressure, and nausea/vomiting. These can occasionally be dangerous. Cardiac arrest is an unlikely, but possible, result.
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A Resolved Case of Post-Op Urinary Retention
A 75-year-old man arrived in the recovery room after a surgery of about 1.5 hours under general anesthetic.
Upon arrival, the man was agitated and not able to answer questions. His blood pressure was high but his heart rate was low. He was assumed to be in pain, given his agitation, but didn't improve much after medication. He began to sweat and experience ectopy (irregular heart beats).
The anesthesiologist and recovery nurse realized he had not emptied his bladder before going in for surgery. He had a history of prostate enlargement and had received over a liter of IV fluids in the operating room. His bladder was emptied with a urinary catheter. Almost immediately, his heart rate climbed back to normal, his blood pressure corrected, and his agitation disappeared. After a short nap, he woke up feeling just fine with no recollection of having the catheter placed. He had no further issues and was discharged to go home.
General Anesthesia and Bladder Function
As summarized in the above video, there are many points along the pathway that could interrupt normal bladder emptying.
A Final Word
Note: While the author is a board-certified physician-anesthesiologist, this article is for informational purposes only and should not be taken as medical advice or used for diagnosis or treatment. Consult your physician if you are concerned about post-operative urinary retention.