SERIES Effects of Analgesic and Anesthetic Medications on Lower Urinary Tract Function Sammy E. Elsamra and Pamela Ellsworth he lower urinary tract (LUT), which consists of © 2012 Society of Urologic Nurses and Associates the bladder, urethra, and Ellsworth, P., & Elsamra, S.E. (2012). Effects of analgesic and anesthetic medica- urinary sphincter, serves tions on lower urinary tract function. Urologic Nursing, 32(2), 60-68. Tto allow for the functional storage and elimination of urine. This Analgesic and anesthetic medications may affect lower urinary tract function via complex process is orchestrated a variety of mechanisms. This article reviews the more commonly used medica- tions and their effects on lower urinary tract function. by reflexive neural pathways (which are under control from Key Words: Anesthetic, opioid, ketamine, lower urinary tract function, higher centers) that allow for the urinary retention, analgesia. coordination of bladder and sphincter. The impact of anesthet- Objectives: ics, general or regional, on this 1. Discuss the physiology of micturition. complex neural network may affect this delicate control and 2. Explain the effects of analgesics on the lower urinary tract. may result in urinary retention. 3. Describe the effects of general anesthesia on the lower urinary tract. Although the association between the use of certain medications and the occurrence of acute urinary Physiology of Micturition that converges to form a thickened retention is well established, the association is poorly defined Storage and voiding involves bladder neck controlled by the (Thomas, Chow, & Kirby, 2004). complex interactions between the autonomic nervous system, and a Limited information is available bladder, urethra, urethral sphinc- somatically controlled external regarding the effects of analgesic ter, and nervous system. The uri- component (striated muscle), and anesthetic medications on the nary bladder and urinary sphinc- must relax to allow for the con- LUT. This article provides a sum- ter are the principle components tracting bladder to expel its load. mary of the current available liter- of the LUT responsible for urinary Storage of urine is achieved by ature on the effects of non- storage and voiding. The urinary bladder relaxation and contrac- steroidal, anti-inflammatory drugs bladder, with a typical adult tion of both the bladder neck (NSAIDs); opiates; and spinal capacity of 400 to 500 ml, serves (internal urinary sphincter) and anesthetics on LUT function. to store or expel urine by way of the external urinary sphincter. relaxation or contraction of the Micturition occurs when the blad- detrusor muscle, respectively. The der neck and the external urinary Sammy E. Elsamra, MD, is a Resident, urinary sphincter, composed of an sphincter relax and the bladder Division of Urology, Alpert Medical School, internal component, a continua- contracts, allowing for the unob- Brown Medical School, Providence, RI. tion of detrusor smooth muscle structed expulsion of urine. Pamela Ellsworth, MD, FAAP, FACS, is an Associate Professor of Urology (Surgery) and Pediatrics, Alpert Medical School, Urologic Nursing Editorial Board Statements of Disclosure Brown University, Providence, RI. In accordance with ANCC-COA governing rules Urologic Nursing Editorial Board state- Note: Objectives and CNE Evaluation Form ments of disclosure are published with each CNE offering. The statements of disclosure for appear on page 68. this offering are published below. Statement of Disclosure: The authors Susanne A. Quallich, ANP-BC, NP-C, CUNP, disclosed that she is on the Consultants’ reported no actual or potential conflict of Bureau for Coloplast. interest in relation to this continuing nursing All other Urologic Nursing Editorial Board members reported no actual or potential education activity. conflict of interest in relation to this continuing nursing education activity. 60 UROLOGIC NURSING / March-April 2012 / Volume 32 Number 2 SERIES Bladder storage and emptying, Figure 1. as well as coordinated contraction Neurologic Pathways Involved in Lower Urinary Tract Function or relaxation of the urinary sphincter, are under the control of the sympathetic, parasympathetic, Stimulates and somatic nervous systems Cerebrum (Ouslander, 2004). In general, uri- Inhibits nary storage is a function of the PONS sympathetic nervous system, whereas micturition is a function of the parasympathetic nervous system. While both are autonomic Sympathetic — Hypogastric Nerve functions in nature, the somatic rusor Musc nervous system is responsible for Det le the control of the external urinary sphincter, allowing for volitional continence. As seen in Figure 1, storage of urine (bladder relax- ation and internal sphincter con- traction) is under sympathetic Internal Spinal Cord T10-L2 S1-S4 Sphincter control via impulses transmitted Parasympathetic — Pelvic Nerve through the hypogastric nerve. External Sphincter Somatic — Pudendal Nerve The pelvic nerve is the principle Urethra conduit of the parasympathetic input for the LUT and allows for coordinated voiding by stimulat- Description: The function of the lower urinary tract is under the control of several ing bladder contraction with neurologic pathways. The sympathetic nervous system allows for bladder relaxation sphincter relaxation. The somatic and internal sphincter contraction. This is mediated through the hypogastric nerve, nervous system, through the and these signals originate from the spinal cord at levels T10-L2. The parasympa- pudendal nerve (and to a small thetic system allows for bladder contraction and internal sphincter relaxation. This is mediated through the pelvic nerve, and these signals originate from the spinal degree the pelvic nerve), allows cord levels at S2-S4. The somatic (voluntary) system allows for the control of the for the contraction or relaxation of external sphincter. All three of these systems are part of reflex pathways (not the external urinary sphincter depicted in this illustration) and are under the influence of upper neurologic control (striated pelvic diaphragm muscle (cerebrum and pons micturition center in the cerebellum). under voluntary control). These nerves are lower motor neurons and are under the control of spinal reflexes and upper motor neuron Sturkenboom, Stricker, & Bosch, Bladder Filling/Storage input from the central nervous 2008). Bladder filling/storage is reg- system (Ouslander, 2004). External sphincter motor neu- ulated by two separate storage Storage of urine is primarily a rons originate from Onuf’s nucle- reflexes – the sympathetic (auto- sympathetic and somatic func- us, located on the anterior horns of nomic) reflex and the somatic tion. Sympathetic input to the the sacral spinal cord at levels S2- reflex (Thor & Donatucci, 2004). LUT is mediated through stimu- S4, and send their axons into the The sympathetic-mediated stor- lation of adrenergic receptors. pudendal nerve (and to a lesser age reflex is involved with blad- The stimulation of alpha-1 adren - degree, the pelvic nerve) that stim- der filling and is mediated by ergic receptors at the bladder ulate the striated muscle to con- myelinated A-delta fibers. Affer- neck by post-ganglionic norepi- tract via the release of acetyl- ent activity travels in the pelvic nephrine results in bladder neck choline (Darrah, Griebling, & nerves to the spinal cord. At the contraction. The sympathetic Silverstein, 2009; deGroat, 2006). L1-L3 level, sympathetic activity nervous system also inhibits This acetylcholine then binds to is initiated, which leads to a parasympathetic input into the post-junctional nicotinic recep- decrease in excitatory parasym- bladder, thus inhibiting stimula- tors, resulting in contraction of pathetic stimulation of the blad- tory signals from reaching the the external sphincter. Both der. Postganglionic neurons re- detrusor. Further, stimulation of alpha-receptors and serotonin 5- lease noradrenaline, which binds beta-3-adrenergic receptors with HT2 receptors are located in to beta-adrenoreceptors in the norepinephrine, as shown in ani- Onuf’s nucleus and facilitate the detrusor, leading to detrusor mal models, allows for relaxation storage reflex (Verhamme et al., relaxation (Andersson, 2007). of the detrusor (Verhamme, 2008). UROLOGIC NURSING / March-April 2012 / Volume 32 Number 2 61 SERIES The somatic storage reflex, post-operative use of opioid anal- capacity and compliance follow- often referred to as the “guarding gesia, and the administration of ing intravenous (IV) and intra- reflex,” occurs in response to large volumes [greater than 500 thecal injections of tramadol. In sudden increases in intra-abdom- ml] of perioperative intravenous humans, similar results on blad- inal pressure. In this reflex, affer- fluids) (Koch, Grinberg, & Farley, der capacity and compliance ent activity travels along the 2006). Further, the use of orally have been noted, with a reported myelinated A-delta fibers in the ingested opioids in patients out- increase in bladder capacity pelvic nerve to the sacral spinal side of the peri-operative setting varying from 20% to 65% cord, where efferent somatic ure- has been shown to result in depending on the opioid, dose, thral motor neurons in Onuf’s increased rates of urinary reten- patient group, and route of nucleus are located. Afferent tion (Meyboom, Brodie-Meijer, administration (Dray, 1988; activity is also relayed to the Diemont, & van Puijenbroek, Kuipers et al., 2004; Malinovsky periaqueductal gray (PAG) region 1999). Other risk