A ppt on the basics and interprettation of urodynamic traces

1. Urodynamic Techniques
By Dr Sajad Sultan Lone
Moderator: Dr Yasir Ahmad

2. Why Urodynamics?
• Patient symptoms are often misleading
• The lower urinary tract, both during filling and emptying, is
a dynamic system.
• Urodynamics is a dynamic study of urine storage and
transportation

3. Types
• Simple and Complex
• Simple : Micturition Charts,Voiding Diary, Frequency
Volume Chart, UFM, Pad Testing, Surface EMG
• Complex : Pressure flow study, Cystometry, UPP, Needle
EMG, Whittaker Test

4. Aims
• To reproduce the patient’s symptomatic complaints during
urodynamics, and
• To provide a pathophysiological explanation by correlating
the patient’s symptoms with the urodynamic findings
• To increase diagnostic accuracy above that which can be
achieved by nonurodynamic means.
• To predict problems that may follow treatment
interventions
• To assess the natural history of lower urinary tract
dysfunction

9. Environment
• To be performed in a calm environment with full privacy
• Procedure to be explained to the patient
• Give adequate time to each patient
• No antibiotics are required

10. Cystometry
• Pressure-volume relationship of the bladder is measured
• Normal and abnormal lower urinary tract function
described in terms of bladder and urethral behaviour
during the storage and voiding phases

11. Performing Filling Cystometry
• The role of urodynamics is to reproduce the patients
symptoms
• The role of urodynamics is to provide a pathophysiological
explanation for the patient’s complaints
• There should be a continuous dialogue between the
investigator and the patient throughout the investigation to
assess
• Bladder sensation
• Detrusor activity
• Bladder compliance
• Urethral function
• Bladder capacity

12. Bladder Sensation
• First sensation of filling (FSF) It occurs at approximately
50% of cystometric capacity
• Normal desire to void (NDV). The feeling that leads the
patient to pass urine at the next convenient moment, but
voiding can be delayed if necessary. It is felt at about 75%
of cystometric capacity
• Strong desire to void (SDV). Persistent desire to void
without the fear of leakage. It is felt at approximately 90%
capacity
• Urgency. This is defined as a sudden compelling
persistent desire to void which is difficult to defer
• Pain

13. Abnormal sensation
• Increased (hypersensitive) : there is an early first
sensation of filling (FSF) at less than 100 ml which,
instead of passing away until the normal desire to void
(NDV) occurs, persists and increases, limiting the
cystometric capacity to less than 250 ml.
• Reduced. Reduced sensation is characterised by a later
FSF and NDV, with the patient never experiencing a
strong desire to void (SDV) or urgency
• Absent. Absent sensation necessitates the patient
passing urine “by the clock”

14. Detrusor Activity
• The normal detrusor remains quiescent during filling and
detrusor overactivity does not occur under any
circumstances
• Detrusor relaxes and stretches to allow the bladder to
increase in size without any change in pressure
(accommodation)
• Detrusor overactivity exists when, during the filling phase,
there are involuntary detrusor contractions
• “Detrusor overactivity incontinence”

15. Normal filling cystometrogram with almost no increase in pdet as the bladder fills

16. Is DO Normal or Abnormal?
• Do you feel anything now?”
• “Is this the feeling that gives you trouble in your everyday
life?”
• Involuntary detrusor contractions occurring at increasing
frequency and with increasing pressure as the bladder fills

17. Bladder Compliance
• Intravesical pressure should change little from empty to
full
• Relationship between bladder volume and bladder
pressure (Δv/Δp)
• Increase in bladder volume per centimetre of water
increase in pressure (ml/cmH2O)
• With a capacity of 400 ml the change in pressure from
empty to full should be less than 10 cmH2O
(40ml/cmH2O)
• Dependent on the rate of bladder filling, on bladder
function, and on the neurological state of the patient

18. Bladder Capacity
• Cystometric capacity
• Maximum cystometric capacity (MCC)
• Maximum anaesthetic bladder capacity

19. Sterility of Transducers and Tubing
• The external transducers need not be sterilised, but
should be flushed through with chlorhexidine solution
(0.2%)
• Catheter tip transducers must be kept sterile using Cidex

20. Media Used for Bladder Filling
• Water or physiological saline
• Radiographic contrast material if videourodynamics is
being performed

21. Temperature of Filling Fluid
• Fluid at room temperature (70ºF or 22ºC).
• Important not to use cold fluid (lower than 20ºC) because,
the use of cold infusion fluid stimulates detrusor
contractility at low bladder volumes

22. Patient Position During Cystometry
• The patient is catheterised when supine
• Can fill the patient either sitting (in the case of women) or
standing (in the case of male patients) because the
supine position does not reflect the everyday stresses to
which the bladder is subjected
• Patients complain of bladder symptoms only when they
are active (erect)

23. Rate of Bladder Filling
• ICS recommends that the exact filling rate is stated for each
test, although the ICS formerly defined three categories of
filling rate:
• Slow-fill cystometry: up to 10 ml/min.
• Medium-fill cystometry: between 10 ml/min and 100 ml/min.
• Fast-fill cystometry: when the rate is greater than 100 ml/min
• A convenient rate, which does not prolong the test unduly, is 50
ml/min to 60 ml/min
• The fastest physiological urine production for any individual can
be calculated by dividing the body weight (in KG) by four (e.g.,
20 ml/min for an 80-KG man).
• Faster flow rates may produce artefactual low compliance in
patients suspected of having detrusor overactivity

24. Qualitycontrol:the patientisaskedto cougheveryminute duringfillingand after voidingto
ensurethat the cathetershavenot becomedisplaced during micturition

25. Voiding Cystometry
• Premicturition pressure is the pressure recorded
immediately before the initial isovolumetric contraction
• Opening time is the time elapsed from the initial rise in
detrusor pressure to the onset of flow
• Opening pressure is the pressure recorded at the onset of
measured flow
• Maximum voiding pressure is the maximum value of the
measured pressure during voiding
• Pressure at maximum flow is the pressure recorded at the
time of maximum flow rate.

26. Performing Voiding Cystometry
• If the patient has little sensation it is important to use the
functional bladder capacity from the frequency- volume
chart as a guide to cystometric capacity
• Void to completion if possible

27. Interpretation of Voiding Cystometry
• Detrusor Activity:
• Normal when the detrusor contracts to empty the bladder
with a normal flow rate
• Underactive when either the detrusor contraction is
unable to empty the bladder or the bladder empties at a
lower than normal speed, and
• Acontractile when no measured detrusor pressure change
occurs during voiding

28. Detrusor underactivity: a poor detrusor contraction results in a fluctuating and interrupted
flow wave.

29. Acontractile detrusor: PFS in a male patient who voids by straining without any
sign of detrusor contraction

30. Assessment of detrusor contractility by using the “stop test” : pdet, iso

31. Stop test: small increase in Pdet,iso (20 cmH2O) in a female patient

32. Detrusor Underactivity
• When the patient cannot initiate micturition and it is
unclear whether this inhibition is psychogenic or
neurogenic
• Psychogenic suppression of detrusor contraction is less
common if the patient is put at ease

33. Detrusor-sphincter dyssynergia (DSD)
• Seen only in patients with neurological disease and most
classically in high-level (cervical) spinal cord injury
• Phasic contractions of the intrinsic urethral striated
muscle during detrusor contraction

34. Dysfunctional voiding (DFV)
• Produces the same urodynamic pattern as DSD but
occurs in a different group of patients and has a different
cause
• In children who are neurologically normal but present with
urinary incontinence and/or infections
• The interrupted flow in these children is due to pelvic floor
overactivity rather than to intrinsic striated muscle as in
DSD

35. How is the diagnosis of BOO made?
• by plotting the maximum flow rate (Qmax) against
detrusor pressure at Qmax (pdet, Qmax) into the ICS
nomogram which is derived from the Abrams-Griffiths
• BOOI = pdet, Qmax – 2Qmax
• If the BOOI is greater than 40 then BOO exists; if it is
below 40 then no definite BOO exists

36. Example Traces

60. sss

62. Thank You