“Urodynamics is a collection of tests used to measure bladder, urethral, and pelvic floor muscle function, as well as diagnose functional disorders of the lower urinary tract” (Gray, 2010, p. 321). Urodynamics is used in addition to the patient’s history and a complete patient assessment. Moore (2013) states that urodyamics encompasses a number of tests, these include: flow study, cystometry, urethral pressure profile and leak point pressure. For the purpose of this paper a urodynamic test will be analysed to highlight normal and abnormal results. Possible reasons for these abnormalities will be discussed.

In this study the patient is a 42 year old lady who presented with a number of pelvic floor problems including urgency, urge incontinence and prolapse. Examination revealed a moderate cystocoele and rectocele. Urodynamic evaluation was performed in order to objectively assess bladder function and therefore assist in recommendations for further treatment.

Cystometry “is a measure of bladder pressure in response to filling. Several parameters are measured: bladder filling, sensation, stability, compliance, capacity, control over micturition, detrusor contractility and empting” (Ghoniem & Khater, 2008, p. 36)

Mahfouz, Afraa, Campeau, and Corcos, (2011) report that the normal parameters during filling for females are as follows: first sensation at 100-250mls, first desire at 200-330mls and strong desire at 350mls-560mls.A healthy bladder should accommodate 500mls comfortably and the detrusor (pdet) should remain nearly at zero whilst filling (p. 270-271). The results in this study are abnormal for the following reasons. Bladder sensations were felt at less than normal volumes. First desire was expressed at 100mls and strong desire at 219mls. Filling was stopped prematurely at 399mls due to increasing bladder pain. Detrusor overactivity occurred which resulted in the pdet steadily increasing to a maximum of 19cmH20. The pdet remained elevated once filling had stopped. These results are indicative of decreased bladder compliance. Patel (2008) states that compliance relates to the bladders ability to distend and hold urine. In decreased bladder compliance the detrusor (pdet) rises steadily in an uninterrupted line at low volumes and remains elevated once filling has stopped. Bladder discomfort is also experienced (pp. 63-65). These abnormal findings were demonstrated in this study. “Bladder compliance is considered to be compromised if it is below 30cmH20” (Mahfouz et al. 2011, p. 277). In this test compliance was 22cmH20. Gray (2011a, p. 220) states that low bladder compliance can be caused by numerous pathology. Chronic bladder outlet obstruction is a common cause. It can be due to any anatomical obstruction such as pelvic organ prolapse, bladder neck obstruction, urethral diverticulum or prior incontinence surgery. Chronic inflammation, neurologic disorders and interstitial cystitis are also causes.

Testing for stress incontinence is also performed. Moore (2013) defines urodynamic stress incontinence as leakage which occurs with a rise in intra abdominal pressure, but without a rise in detrusor pressure (pdet). Intra abdominal pressure is increased by asking the person to cough. The urethral sphincter pressure is also measured via a maximum urethral closure pressure reading, also known as an MUCP. This reading indicates if the urethral sphincter mechanism is competent. An MUCP reading of less than 20cmH20 indicates an incompetent sphincter and the person is said to have intrinsic sphincter deficiency. In this study the MUCP was competent and nil stress incontinence was demonstrated. These are all normal findings. The reasons why stress incontinence was not demonstrated is due to good pelvic floor support of the bladder neck and a good urethral closure pressure. Gray (2011b, p. 272).

Detrusor overactivity is defined “as the urodynamic observation of involuntary detrusor contractions. An overactive detrusor contraction is considered clinically relevant when it is associated with urgency with or without urge incontinence “ (Gray, 2012a, p. 23). Patel (2008) states that an overactive bladder is demonstrated when the detrusor muscle contracts and subsequently causes the pdet to rise above 15cmH20. When the detrusor contractions are strong enough to overpower the urethral sphincter leakage occurs and the diagnoses of urge incontinence is made (p. 65). Detrusor contractions can be experienced during the filling phase or by various provoking activities such as change of position, running water and washing of hands (Flesh, 2014, para.10). In this study detrusor overactivity with a pdet rise to 19cmH20 occurred with water provocation. Strong urgency and moderate leakage were also experienced. The above findings are abnormal, as the detrusor muscle should not contract with any form of provocation and there should not be any leakage of urine. The patient was therefore diagnosed with overactive bladder and urge incontinence

Both Gray (2012, p. 23-25) and Ghoniem and Khater (2008) state that the causes of detrusor overactivity are not fully known or understood (pp.35-45). Overactivity is thought to be either due to neurological issues or to be idiopathic. Examples of neurological conditions include, brain tumour, Parkinsonism, multiple sclerosis and myelitis. Overactivity can also be caused by aging, bladder infection or inflammation and chronic bladder outlet obstruction.

The end void provides valuable information. “Data generated is used to determine the uroflow pattern, detrusor contraction strength, urethral resistance and magnitude of any obstruction” (Gray, 2012b, p. 71). Gray (2012b, p. 75-77) states that the uroflow curve is assessed to determine the type of voiding pattern. A normal flow pattern is continuous. Abnormal flow patterns can be either interrupted, prolonged or strained and are often as a result of bladder outlet obstruction. A normal flow should also produce a detrusor contraction which is able to empty the bladder to completion. According to Moore (2013) abnormal detrusor contractions can be either underactive or acontractile. In this situation a slow flow rate is observed with often high residuals. The cause is commonly neurological (pp. 54-56). A normal female should have a continuous flow pattern with a Qmax of 13- 25ml/s and a Pdet /Max of below 30cmH20 Gray (2012b, p. 75-77). In this study the Qmax was 14ml/s and the Pdet/Max 32cmH20. Even though a prolapse is present, it does not appear to be causing an excessively high voiding pressure nor an abnormal voiding pattern.

It can be said that urodynamics is indeed a useful tool, as it helps the clinician to assess lower urinary tract dysfunction. The information obtained can concur with the subjective and objective data that is already known and therefore confirm that treatment is appropriate. In some cases the results may disprove the current diagnoses and therefore the mode of treatment is changed to suit the new findings. Overall the test allows for appropriate interventions to be implemented which inturn leads to better patient outcomes.

Reference List:

Flesh, G. (2014). Uptodate. Retrieved from http;//www.uptodate.com/contents/urodynamic-evaluation-of-women-with-incontinence

Ghoniem, G. M., & Khater, U. M. (2008). Urodynamics. In G.M. Ghoniem, G.W. Davila & S. D. Wexner (Eds.), Pelvic floor dysfunction (pp. 35-45). London: Springer.

Gray, M. (2010, November-December). Traces: making sense of urodynamics testing - part 2: uroflowmetry. Urologic Nursing, 30(6), 321-326

Gray, M. (2011a, July-August). Traces: making sense of urodynamics testing - part 6: evaluation of bladder filling/storage: bladder wall compliance and the detrusor leak point pressure. Urologic Nursing, 31(4), 215-235

Gray, M. (2011b, September-October). Traces: making sense of urodynamics testing - part 7: evaluation of bladder filling/storage: evaluation of urethral sphincter incompetence and stress urinary incontinence. Urologic Nursing, 31(5), 267-289.

Gray, M. (2012a, January-February). Traces: making sense of urodynamics testing - part 9: evaluation of detrusor response to bladder filling. Urologic Nursing, 32(1), 21-28.

Gray, M. (2012b, March-April). Traces: making sense of urodynamics testing - part 10: evaluation of micturition via the voiding pressure-flow study. Urologic Nursing, 32(2), 71-78.

Mahfouz, W., Afraa, T., Campeau, L., & Corcos, J. (2012). Normal urodynamic parameters in women. International Urogynecology Journal, 23(3), 269-277. doi: 10.1007/s00192-011-1585-y

Moore, K. H. (2012). Urogynecology : Evidence-Based Clinical Practice. London:springer.