Does posture affect micturition?

Rane, Ajay (2011) Does posture affect micturition? PhD thesis, James Cook University.

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Abstract

Posture during toileting and its effect on toileting has been under scrutiny for more than 7000 years. With the advent of the western toilet in the 19th century and a more closeted approach to toileting, the effects of posture became even more important to study because the visual one to one education of children, regarding toileting became less and less. Wennergren in her study of children demonstrated the value of foot support to relax the pelvic floor during urination in children. Moore in her study showed that a majority of British women will not sit on the toilet outside their house and would 'hover' to pass urine. A Taiwanese study showed a similar trend except that young students would precariously perch in a squat over a western toilet than sit on it for hygiene reasons. All these studies stimulated the generation of this thesis.

PRINCIPAL OBJECTIVES AND SCOPE OF THE STUDY

The principal objectives of these investigations were to study

- The effect of the 'lean forward' position on the western toilet (WT) compared to the 'sit upright position' during micturition.

- The effect of the 'raised knee' position on the western toilet compared to the 'lean forward' position during micturition.

- The effect of squatting on a custom built Asian toilet compared to 'lean forward' position on the western toilet. What was learnt led to numerous 'sub-studies' on squatting which included -

- Study of squatting in volunteers leading to a 'squatability' index

- Study of school children and their ability to squat

- Study of abdominal pressures in squatting and sitting positions at rest and during Valsalva manoeuvre

- Study of the levator hiatus during squatting and lying down at rest

- Possible design of a retro fit device to aid toileting on the western toilet called Duneze

METHODOLOGY

All toileting parameters were studied using uroflowmetry which was used as standard, as in previous studies. [1-6]

Support for Uroflowmetry, which is a simple non-invasive measurement of urine flow over time and an indication in screening for voiding difficulty, as a screening test for voiding dysfunction has become stronger over time, [7-9] measuring some of the key components of the micturition process. [10] An abnormally slow urine flow suggests a provisional diagnosis of voiding difficulty subject to test repetition, post-void residual bladder volume (PVRBV) measurement and possible voiding cystometry.

Post Void Residual Urine Volume Measurement of post void residual urine volume (PVRBV), the amount of residual urine in the bladder after a voluntary void, is another non-invasive screening test for evaluating voiding dysfunction. Most urologists agree that volumes of 50 mL to 100 mL constitute the lower threshold defining abnormal residual urine volume PVRBV measurement. There are 2 methods of measuring PVRBV: sterile catheterization and bladder ultrasound. Although sterile catheterization provides a urine sample, there are many disadvantages associated with the procedure: it causes patient discomfort, carries a risk of urethral trauma and introducing an UTI, is time-consuming, and may not be necessary. [11]

In contrast, bladder ultrasound can be performed with a portable device. It is noninvasive and time-efficient, minimizes medical waste and supplies, and determines when catheterization is medically appropriate. However, a urine specimen cannot be obtained during this procedure. Portable 3-dimensional ultrasound devices have been shown to provide highly accurate measurement of bladder volume. Coombes and Millard compared the BladderScanTM BVI 2500 series (Diagnostic Ultrasound, Bothell, Wash) with catheterization for the measurement of bladder volume with no significant difference in estimates being demonstrated. The overall accuracy (94%), sensitivity (97%), and specificity (91%) of the BVI 2500+ were encouraging. [11] The current accuracy of modern uroflowmeters in measuring urine voided over time (flow rate) is approximately ± 2–5%, despite the fact that a variety of different physical measurement principles are being used. This accuracy compares favourably with the ± 20–25% for the most accurate ultrasonic techniques for PVR measurement with the potential error using urethral catheterisation being much higher. [12]

After obtaining Institutional ethics approval for all studies, volunteers recruited from nursing staff and medical students participated in these studies coached either by Audrey Corstiaans (AC) or Professor Ajay Rane (AR).

SUMMARY OF RESULTS

STUDY ONE: There was a statistically significant difference in the peak and average urine flow rates in the lean forward position when compared to the sit back posture (p<0.0054 and p<0.0097 respectively).

STUDY TWO: There was a statistically significant difference in uroflowmetric parameters i.e. the peak (p=0.01) and average flow rates (p=0.043), when tested in the lean forward position as compared to the knee raised position respectively. Hence the importance of knee raising or leaning forward with feet stability was deemed equally important when toileting.

STUDY THREE: This was the most challenging of studies. In summary, only 46% of our volunteers from a cohort of 125 could actually squat (with feet flat for more than 30 seconds). [13] Although not statistically significant, in volunteers who could squat there was a trend to better urine flows especially the "time to maximum flow" (p=0.003) in the squatting position when compared to the lean forward position.

The results of the Study One encouraged us to consider the possibility that an alternative position during toileting would be beneficial in effecting voiding. This lead to the evaluation of Uroflowmetric parameters in the lean forward and raised knee position (Study Two). Encouraged by the results of Study Two we raised the bar even higher and asked patients to squat during the act of voiding. Although no firm conclusions could be drawn from this study the main challenge arose from the fact that less than half of our volunteers could not squat.

PRINCIPAL CONCLUSIONS

The main conclusions derived from these studies are:

- Posture on the toilet affects bladder function

- On the western toilet the lean forward position with foot support is the most optimal

- Squatting position is difficult to assume in a majority of the population who do not routinely use squat toilets.

Item ID: 29819
Item Type: Thesis (PhD)
Keywords: squatting; micturition; toileting posture
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Additional Information:

Appendix B (publications) is not available through this repository.

Publications arising from this thesis are available from the Related URLs field. The publications are:

Rane, A., and Corstiaans, A. (2008) Does micturition improve in the squatting position? Journal of Obstetrics and Gynaecology, 28 (3). pp. 317-319.

Date Deposited: 24 Oct 2013 02:26
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1114 Paediatrics and Reproductive Medicine > 111402 Obstetrics and Gynaecology @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920119 Urogenital System and Disorders @ 100%
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