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ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY CATHETERIZATION IN THE INTRAPARTUM
PERIOD
A dissertation submitted to the Tamil Nadu Dr. M. G. R. Medical University, Chennai in partial fulfilment of the requirement for the MS in Obstetrics and Gynaecology (Branch II) degree examination to be held in May 2020
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ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY CATHETERIZATION IN THE INTRAPARTUM
PERIOD
Dissertation submitted to the
THE TAMIL NADU DR.MGR MEDICAL UNIVERSITY, CHENNAI In partial fulfilment of the requirements for the degree of
MASTER OF SURGERY IN
OBSTETRICS AND GYNAECOLOGY By
VERONICA.M
Register Number: 221716411
DEPARTMENT OF OBSTETRICS AND GYNAECOLOGY CHRISTIAN MEDICAL COLLEGE
VELLORE MAY 2020
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CERTIFICATE
This is to certify that
“ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY CATHETERIZATION IN THE INTRAPARTUM
PERIOD”
is the bonafide work of Dr. Veronica .M under my supervision in the Department of Obstetrics and Gynaecology, Christian Medical College, Vellore in partial
fulfillment of the requirements for the M.S Obstetrics and Gynaecology Examination Branch II of the Tamil Nadu Dr. M.G.R Medical University to be
held in May 2020 and no part thereof has been submitted for any other degree.
Dr Jiji Matthews Professor, Department of Obstetrics and
Gynaecology
Vellore Christian Medical College, Vellore – 632004
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CERTIFICATE
This is to certify that
“ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY CATHETERIZATION IN THE INTRAPARTUM
PERIOD”
is the bonafide work of Dr. Veronica M under my supervision in the Department of Obstetrics and Gynaecology, Christian Medical College, Vellore in partial
fulfillment of the requirements for the M.S Obstetrics and Gynaecology Examination Branch II of the Tamil Nadu Dr. M.G.R Medical University to be
held in May 2020 and no part thereof has been submitted for any other degree.
Dr. Jiji Matthews Dr Anna Pulimood Professor and Head, Principal, Department of Obstetrics and Gynaecology, Christian medical college Christian Medical College, Vellore- 632004 Vellore -632004
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DECLARATION
I, Veronica M, do hereby declare that the dissertation titled “ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY CATHETERIZATION IN THE INTRAPARTUM PERIOD” is a genuine record of research done by me under the supervision and guidance of Dr. Jiji Matthews, Professor, Department of Obstetrics and Gynaecology, Christian Medical College, Vellore and has not previously formed the basis of award of any degree, diploma, fellowship or other similar title of any university or institution.
October 2019 Dr Veronica. M
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This is to certify that this dissertation work titled “ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY
CATHETERIZATION IN THE INTRAPARTUM PERIOD” of the candidate Dr. Veronica.M, with registration number 221716411 for the award of M.S. Obstetrics and Gynaecology. I personally verified the www.urkund.com website for the purpose of plagiarism check. I found that the uploaded thesis file contains from introduction to conclusion pages and the results show 9% of plagiarism in the dissertation.
Dr. Jiji Matthews Professor and Head
Department of Obstetrics and Gynaecology Christian Medical College, Vellore- 632004
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ACKNOWLEDGMENTS
Throughout the writing of this dissertation I have received a great deal of support and assistance.
I would like to express my sincere gratitude to my guide, Dr. Jiji Matthews, Professor of Obstetrics and Gynaecology-Unit V, Christian Medical College and Hospital, whose expertise was invaluable in the formulating of this research topic
and methodology in particular. I would also like to thank her, for her valuable help, guidance and support in this endeavor.
I would like to thank my co guides Dr. Swathi, Associate Professor of Obstetrics and Gynaecology Unit V, Christian Medical College for her constant support and
encouragement.
My heartfelt gratitude to Mrs. Gowri Mahasampath, Department of Bio –statistics and Mr. Madhan, from department of CEU, for their help and assistance.
I thank my parents, my brother and friends for their support and sympathetic ear.
Above all I would like to thank Lord Jesus for His strength throughout this endeavor and for helping me to complete this project with success
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INSTITUTIONAL REVIEW BOARD (IRB) APPROVAL LETTER
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CONTENTS
S. No TITLE PAGE NO
1. INTRODUCTION 15
2. OBJECTIVES 19
3. REVIEW OF LITERATURE 20
4. MATERIALS AND METHODS 53
5. RESULTS 59
6. DISCUSSION 87
7. CONCLUSION/LIMITATIONS 93/94
8. BIBLIOGRAPHY 95
9. APPENDICES 110
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ABBREVIATIONS
CI - Confidence interval CCC - Complex continuing care LTC - Long-term care
PVR - Postvoid residual
RCT - Randomized controlled trial UI - Urinary incontinence
UR - Urinary retention UTI - Urinary tract infection BOO - Bladder outlet obstruction LoA - Limits of agreement
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ESTIMATION OF URINE VOLUME BY ULTRASOUND TO PREVENT UNNECESSARY CATHETERIZATION IN THE INTRAPARTUM
PERIOD INTRODUCTION INTRAPARTUM PERIOD
The duration from the onset of labor to the delivery of the placenta constitutes the intrapartum period. During this period ,the lower urinary tract elasticity increases. This is because of the reduction in smooth muscle tone, which is hormone induced. The capacity of the bladder increases during pregnancy, due to the decrease in detrusor muscle tone and this begins in the third month of gestation. (1-2).
Due to the use of regional anaesthesia, micturition difficultiescan be encountered.These are due to neurological deficits which includes impaired reflex mechanism, voluntary relaxation of the sphincter urethrae, pelvic and periurethral floor muscles.
When there is massive distension of urinary bladder, there can be impairment of the contractility and function of the detrusor muscle. (3). Women in established labour should be encouraged to void every three to four hours in
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order in order to avoid the effects of a full bladder on delaying the progress of labour, and the risk of postpartum haemorrhage (4).
URINARY CATHETERIZATION
Women who were on neuraxial analgesia had higher post void residual urine (PVR) which was significant .It was found that women on neuraxial analgesia required more catheterization of bladder , than with women who were not on neuraxial analgesia. Catheterization is done unnecessarily on some occasions. Urethral catheterization has the risk of urethral trauma, increased risk of urinary tract infection, urethral stricture (repeated catheterizations) as late complication and negative impact to the woman psychologically. The combination of bacteriuria coupled with urinary retention introduced by catheterization, into an already traumatized urethra and bladder wall, along with pregnancy-induced renal pelvis dilatation and ureteral dilatation, may present the optimal conditions for the development of urinary tract infection in pregnant women(5,6).
At present, there is no systematic or standard way to determine whether a woman needs a urinary catheter during labour. Attending midwives and doctors usually assess the need for catheterisation by palpating the bladder per abdomen, calculating the amount of fluid infused or the interval from last void, all of which
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are imprecise estimates. The use of ultrasound techniques to assess bladder volumes have been investigated in the pregnant patient, in the postpartum state.
The use of ultrasound scanners reducing the risks involving this invasive action in place of intermittent urinary catheterization has been found to reduce the incidence of UTI by 50% (7- 8).
ULTRASOUND IMAGING
Ultrasound has been in use for many years now ,to measure bladder volume. Compared with catheterization, Ultrasonography is simple, quick, noninvasive, painless, and repeatable, accurate. As compared to catheterization, it is not associated with any undesirable side effects. It can be easily operated by minimally trained personnel at any place. It has been shown to have good correlation with or to have good accuracy when compared with the catheterized volume of the urinary bladder.
90% bladder volume can be calculated to within ±15 using ultrasound along with a suitable correction factor for improved accuracy(9). There are several formulae that has been in use to calculate bladder volume using transabdominal ultrasound.
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Most of the researchers have found Prolate ellipsoid formula for having a better estimation.
In view of above information, the aim and purpose of this study is to assess the accuracy of ultrasound estimation of bladder volume in term patients during the intrapartum period and thereby by correlating it with the catheterized volumes and also to reduce unnecessary urinary catheterizations.
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AIM AND OBJECTIVES
To assess the bladder volume in a patient at term in labour by ultrasound estimation.
To correlate the ultrasound finding with catherised volume
To find out the use of ultrasound as a tool to avoid unnecessary catheterization.
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REVIEW OF LITERATURE
THE ANATOMY OF THE URINARY BLADDER
The urinary bladder has two functions such as to store urine and to expel urine at the required time. The shape and size of the urinary bladder is determined by the volume of urine contained in it and in a pregnant patient , it is dependant also on the gravid uterus. (10).
At birth, the bladder is an abdominal organ , rather than a pelvic organ. It extends from about two-thirds towards the umbilicus .It beomes to the adult position only after puberty (11). The urinary bladder varies in different individuals in shape, size, position and its relation to other structures. The urinary bladder, is tetrahedral in shape when its empty and comes to lie in the abdominal cavity when it is full.
The different parts of urinary bladder are neck, apex, fundus, , a superior and two inferiolateral surfaces (12). The neck forms the lowest part of the bladder and not the base of the bladder. The neck of the bladder lies 3-4 cm behind the the symphysis pubis and is fixed. This corresponds to an area above the plane of the
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inferior aperture of the lesser pelvis (10).The base is posterior-inferior and is triangular in shape .It is closely related to the anterior vaginal wall.
Figure 1:Anatomy of urinary bladder in a woman.
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FUNCTIONAL ANATOMY OF THE LOWER URINARY TRACT
The main function of the urinary bladder is to store and expel urine from the body (13). The intraurethral pressure has to be greater than the bladder pressure so as to maintain continence of urine,. The maximum urethral closure pressures are recorded at the external urethral sphincter within the walls of the bladder(14).
Micturition is is a process of spinal reflexes .It has a facilitatory area in the pons and its inhibitory centre is in the midbrain . These are subject to voluntary control and inhibition (15).
The bladder is an organ with good compliance. This means that changes in volume of the bladder tend to not have a sudden effect, in case of increasing pressure inside the bladder under usual circumstances. Howeve, Bladder has the property of plasticity which maintains a stable tension when the normal bladder .volumes are exceeded . There is relaxation of the pelvic floor muscles when the act of micturition begins.This causes a caudal displacement of the detrusor muscle
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which allows the initiation of micturition (15). However the perineal muscles and external sphincter can be contracted voluntary during micturition.
Figure 2:Functional anatomy of female urinary bladder
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PHYSIOLOGY OF MICTURITION
The normal capacity of a female bladder is approximately 500 mls (14). Urine enters the bladder via the ureters. This contains smooth muscle arranged in a spiral, longitudinal , circular bundles. Specific type of contractions called Vermosis type contractions allows the urine to move from the renal pelvis to the urinary bladder. There must be coordination between relaxation of the urethral sphincter and contraction of the detrusor muscle to facilitate voiding (16). This is carried out with the help of three groups of peripheral nerves which are the somatic nerves-pudendal nerves, the thoracolumbar nerves comprising of hypogastric and sympathetic chain nerves, and the sacral parasympathetic -pelvic nerves (17). Sacral afferents are seen innervating the fundus and trigone .The lumbar afferents are seen in the trigone of the bladder (18).
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Figure 3: Physiology of micturition
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Phases of Micturition FILLING PHASE
The urine that is being produced by the kidneys enters the bladder via the ureters. As the filling starts, afferent impulses are sent to the sacral roots of S2-4 throught the pelvic nerves. These afferent impulses are are sent through the stretch receptors which are located in the walls of the bladder (19). From the sacral roots, Through the lateral spinothalamic tracts,it then goes to the the spinal cord (19).
The responses are then transmitted to the to detrusor muscle from the basal ganglia .These impulses also inhibit the descending impulses coming from the basal ganglia. As the bladder filling begins, these afferent signals are then transmitted to the cerebral cortex .The first sensationto void occurs at 250 mls and is signaled from the cerebral cortex (19). The inhibition of the detrusor muscle is also from the cerebral cortex (19). These afferent impulses along with the desire to void continues to increase as the bladder gets filled and there is conscious inhibition of micturition by the individual(19). As the bladder gets filled to to the maximum capacity there is a voluntary contraction of the pelvic floor and this helps in closure of urethra.
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STORAGE PHASE
Sesnsory input in required to maintain bladder control to avoid awkward situations. When there is a delay in bladder filling sensation or no saensation at all,then it means that the function of the bladder is getting affeceted. Usually the patient has control over voiding and he/she voids when its is convenient . (20).During the storage phase, the bladder outlet is closed and the bladder is in dormant phase. During the storage phase , the intravesical pressure is kept low so as to allow storage of urine, simultaneously allowing increase in bladder volume.
The sensory nerves supply to the urinary bladder are two-which are myelinated A- delta or unmyelinated C fibres. The unmyelinated fibres act as the afferents to the mucosa .The detrusor muscle afferents could be myelinated A delta or unmyelinated C fibres (21,22). These afferent nerves respond to distension of the bladder .Thus pelvic myelinated A-delta fibres form the afferents of the micturition reflex.
The nociceptors which are the unmyelinated units send signals when bladder distends enough to cause pain (23). During bladder filling, A-delta and C-fibres
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responds to the non-painful sensation (24). Finally, the continence is maintained by the contraction of the pelvic floor and urethral sphincter. Efferents impulses from the Onuf’s nucleus activate the receptors by the release of norepinephrine.
Thus continence is maintained by the contractions of pelvic muscles and urethral sphincter (25).
VOIDING PHASE
The three components of micturition are feeling of awareness of the opening of the urethral sphincter followed by passing of urine throught the urethra and a thermal. There is relaxation of the pelvic floor followed by inhibition of the sympathetic neuronal activity .This leads to relaxation of the urethral smooth muscle and relaxation of the rhabdosphincter voluntarily (19). Following this, there is immediate reflex that leads to removal of inhibition of voiding .Now the detrusor muscles is under the control of the parasympathetic system and is then signaled to contract to facilitate voiding (19). When the act of voiding is complete, the cortical inhibition of voiding gets resumed . This in turn causes relaxation of the detrusor muscle. Following this the pelvic floor gets elevated and the rhabdosphincter contraction follow. There is voluntary contraction of the perineal muscles and rhabdosphincter muscles and this prevents urine from being expelled .There is also no interruption of the flow once micturition starts (19,24). Due to
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any reason if micturition gets postponed ,then there is sensation of impendig voiding and a vague suprapubic pain that is felt by the patient (26).
Figure 4: Phases of micturition
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PREGNANCY AND THE BLADDER
There is increased perfusión to all vital organs during preganancy including the kidneys and in turn there is increased urine production. There is increase in glomerular filtration rate by 50% (27). There is also increased levels of relaxin and the weight of the gravid uterus that cause an increase in bladder neck mobility All these changes have a great impact on the genitourinary tract during pregnancy.
The increased amount of circulating relaxin during preganncy helps in reducing stress urinary incontinence . On the other hand , the weight of the preganant uterus cause an increase in the frequency of micturition(28). Due to these reasons, the first sensation to void in pregnancy is reduced and the bladder volume capacity is also apparently reduced. (29).
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Figure 5: Pregnancy and urinary bladder
URINARY RETENTION
Inability to empty the bladder completely is urinary retention. Urinary retention can be acute or chronic. Acute urinary retention happens suddenly and lasts only a short time (9),Eeven though they have a full bladder, people with acute urinary retention cannot urinate at all. Acute urinary retention, a potentially life-
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threatening medical condition, requires immediate emergency treatment (28).
Acute urinary retention can cause great pain and discomfort . Chronic urinary retention can be very troublesome and can become a long lasting medical condition. People with chronic urinary retention can urinate . However, they do not completely empty all of the urine from their bladders (29). People are not aware they have this condition until they develop another problem, such as urinary incontinence, resulting in the accidental loss of urine— or UTI.
ANAESTHESIA IN OBSTETRICS EPIDURALS/SPINAL ANAESTHESIA
An ideal anaesthetic agent is one which can be easily administered and at the same time can provide adequate pain relief . It should not have side effects on mother or fetus in case of preganancy. In 1963,Continuous infusion of local anaesthetic drugs into the epidural space was first described (30). In epidural analgesia an a local anaesthetic drug such as lidocaine or bupivacaine or an opioid drug such as morphine or fentanyl is injected into the epidural space of the lumbar spine in case of pregnancy (31). The drugs act on the spinal nerve roots and the paravertebral nerves . There is free movemnet of drugs across the dura into the
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subarachnoid space (32).In Spinal anaesthesia , the drug is injected into the subarachnoid space . Hence there is rapid onset of action of the anaesthetic drug than the epidural anaesthesia (33).
The pains during labour and delivery occur from two main sources. The first, the uterine contractions and dilatation of the cervix and the second from the stretching of the perineum (34). The pain from the stretching of the perineum is transmitted via the pudendal and sacral nerves (S2 to S4) (34). Insertion point of the epidural is at the lumbar vertebral space below the level of L1 (35). Once the epidural is sited the local anaesthetic is combined with the local opioids (Glosten B 2000).
Maintenance of analgesia is obtained by either continuous infusion of dilute local anaesthesia and opioids or a patient controlled administration (34).
EPIDURAL ANALGESIA / URINARY RETENTION
Urinary retention can occur in apidural anaethesia due to bsensory and motor blocks. Thus by avoiding this , dense motor and sensory blocks urinary retention can be reduced(34). Dense paralysis cannot be prevented in epidural analgesia.
Other adverse side effects of neuraxial anaesthesia incluses hypotension,headaches high level blocks which lead to respiratory compromise,
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and non-reassuring cardiotocographs in fetuses (36). Urinary retention due to neuraxial analgesia can be treated in many ways. But the initial treatment invloves urinary catheterisation. There was a survey which was conducted on postpartum and intrapartum bladder care . This survey reported 189 units in England and Wales and showed a wide variety in practice in management of urinary catheterisation(37). There is not much data that is available with regards to good evidence based guidelines for bladder care during in the Intrapartum and postpartum period. The NICE guidelines only suggest that if a women has not passed urine within six hours following delivery, then efforts should be taken to help her initiate micturition. If she still has not passed urine evn after the routine measures,then she should be catheterised . This allows for measurement of the bladder volume (NICE 2006). Traditionally, this involves passing a urethral catheter to empty the bladdern . However it causes severe discomfort for the patient and has a high risk of getting a urinary infection or urethral trauma (29).
URETHRAL CATHETERIZATION
In major surgeries like Radical or transvaginal hysterectomy, all patients require an indwelling catheter for 5-7 days to completely empty the bladder following surgery. However, after the removal of the catheter, postvoid residual urine volume (PVR) is recommended evaluate to determine the need for re-insertion of
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the catheter. Re-insertion of the catheter is usually indicated when PVR is more tan 100 ml (37). Urinary catheterisation has become the gold standard t measure PVR. It is accurate although it causes great discomfort to the patient.It also increases the risk of urethral trauma, and chances of contracting urinary tract infection (8).
URINARY TRACT INFECTION
Urinary tract infections (UTIs) is the most common infection during pregnancy (38). Traditionally UTI is classified into the lower urinary tract infection or acute cystitis or the upper urinary tract infection or acute pyelonephritis. Bacteruria is a precursor to UTI especially in pregnancy. Asymptomatic bacteriuria is defined as the presence of a positive urine culture in aa patient who is asymptomatic .This is seen in 2 to 7 percent of all pregnancies (38). Rates of Asymptomatic bacteriuria in the pregnant and non-pregnant population are similar. However , due to the anatomical and physiological changes in pregnancy in urinary tract, bacteriuria during pregnancy has increased chances to progress to ascending infection than in the non pregnant woman (34, 39). Pregnancy is associated with a rapid increase in progesterone levels . This leads to ureteric dilatation and urinary stasis. This in turn leads to increase in the risk of bacteriuria. The risk of asymptomatic
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bacteriuria is increased by mechanical pressure from the gravid uterus and the physiological changes associated with pregnancy as described (39).
CATHETER ASSOCIATED-BACTERIURIA
Across the world, Catheter associated bacteruria is the most common cause of health care associated infections(40). It accounts for 40% of hospital-acquired infections .It has been found that 15% to 25% of patients in general hospitals are being catheterized everyday during their stay (3, 31),. It has been shown that the rate of catheterization has also increased (40). Even though patients are being catheterized for 2-4 days, many patients retain their catheter for longer duration of time.
Catheter associated bacteriuria is one of the most common infections among LTCFs (40), they are not symptomatic and hence difficult to diagnose.
Symptomatic respiratory and skin and soft-tissue infections are found to be more common than UTI(40).
In nursing homes, 5% to 10% of patients managed are on a catheter(34, 41).
.Almost all these patients develop bacteriuria at some point in time(42). More than 100,000 patients in US LTCFs ,have a urethral catheter in place .
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The duration of catheterization is the most important risk factor for the development of bacteriuria and the the incidence in indwelling catheterization is 3-8% (43,44,45). Other risk factors associated with catheter associated bacteriuria could be female sex, positive urethral culture results, not receving antibiotic treatment on time, coloniziton of the uro bag, aseptic precautions not taken while catheterization, old age group, immunocompromised state,and renal failure. The rate of bacteriuria depends on duration of the indwelling cathere and the frequency and follow up of the culture reports.It is said that all patients develop bacteriuria in onemonth of acquiring the catheter. (46). In a study of patients on clean intermittent catheterization, they found that the incidence of catheter associated Urinary infection was much lesser in people with reduced frequency of catheterization. (47)
COMPLICATIONS OF SHORT-TERM CATHETERIZATION.
Most patients who have catheter associated bacteriuria are not symptomatic. Also only less than one-quarter of hospitalized patients in ICU develope symptoms of urinary tract infection (47,48). In a study that involved 235 new cases of nosocomial CA-bacteriuria,most patients did not have symptoms of urinary tract infection ( ≥ 90%). Even if they developed symptoms and signs, it was found to
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be similar for patients with and without the catheter (49). Hence it was concluded that urinary tract infection is unnecessarily blamed as a source of fever and leucocytosis in patients in ICU . Urinary tract infection is the most common nosocomial infection in hospitalized patients. It accounts for 15% of all nosocomial infections(50). Bacteremia is seen only in <1% -4%of all cases with bacteriuria (51,52,53).
Unlike the popular belief that urinary tract infection is the most common cause of bacteremias in ICU, it is found that it accounts for only a small proportion.
The mortality rate among patients with nosocomial bacteremic UTI is ∼ 13%.
(54). There are controversies regarding mortality due to catheter associated bacteriuria. Use of sealed catheters was found to have reduction in mortality in a randomized control study which evaluated sealed catheter junctions(55). Patients who require long term catheterizations are already sick and their mortality could be due to septicaemia and bacteremia due to other causes as well.(58) Study done by Saint et al (50) reported that in 1458 hospitalized patients with indwelling bladder catheters, catherter associated bacteriuria was associated with 19% death rates compared to 4 % among non catheterized patients. The adjusted odds ratio for mortality was found to be 2.8 between the two categories(95% confidence interval (CI), 1.5–5.1).
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However according to other other investigators, in studies conducted among patient sin ICU ,there was no significant increase in mortality associated with catheter associated bacteriuria (57).The duration of stay in the hospital was found to be increased by 2-4 days in studies that were done almost 3 decades back(59).
In a study (46) that estimated the duration of stay in hospital ,between catheter associated asymptomatic bacteriuria and catheter associated urinary tract infection, they found that the duration of stay in hospital was shorter for cather associated asymptomatic bacteruria group.
Cost of care for patients with catheter associsted infections have been found to be higher. Each admission for a CA-ASB and CA-UTI costs $589 and $676, respectively. Bacteremia associated with CA-bacteriuria is found to have an estimate of $2836 (55,59). Healthcare costs associated with increased frequency of catheter use adds to $500 million in US each year(60).Asymptomatic bacteriuria which are not detected by routine surveillance cultures do not add on the hospital costs.
COMPLICATIONS OF LONGTERM CATHETERIZATION
Patients in LTCFs are over represented among patients with long-term catheterization. The complications of CA-bacteriuria seen in the acute care setting
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presumably also apply to patients with CA-bacteriuria in LTCFs. Ther was study done among women in female nursing homes who were on indwelling catheter and they found that the number of fever episodes were 1.1 episodes per 100 catherized days. These fever episodes were of low grade and it lasted for les than a day and did not require antibiotic therapy (61). Higher temperatures and fever,were associated with bacteremia and death.. In a blinded autopsy study , 75 aged nursing home patients who died were included. On autopsy , 38% had acute inflammation of the renal parenchyma ,and only 5% of non catheterized had inflammation of renal parenchyma. (P=04).Thus long term catheterization is associated with upper urinary tract inflammation as well. In a prospective 2-year autopsy study of residents 65 years of age in a LTCF, the duration of catheterization was significantly associated with chronic renal inflammation and chronic pyelonephritis . The prevalence of chronic pyelonephritis at death was 10% (5 of 52 patients) for patients catheterized for ≥ 90 days during their last year of life ver-sus 0% (0 of 65 patients) for those catheterized for 90 days P ≤ .02.
Bacteriuria is polymicrobial in nature and is associated with bacteremia . In accounts for 45%–55% of bacteremias (62). Urinary catheterization increases the rate of bacteremias 39 times higher (64).Long termindwelling catheters require
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frequent changing and transient asymptomatic bacteremia occurs in ∼ 4% of these patients (65).
Long term indwelling catheterization is associated with catheter associated urinary tract infection, fever, bacteremia as described earlier, renal parenchymal inflammation, renal and bladder calculi,carcinoma of bladder due to vchronic irritation, fistula formation, incontinence (33).
PATHOGENESIS
Urine in the urinary bladder is sterile and the only mode of infection that can be acquired nosocomially in an otherwise well patient is by urinary catheterization.
Urinary catheterization disturbs the exixting host defense mechanisms . There is provides easier access for the entry of uropathogens to the bladder through the catheter. Through the urethral catheter inoculum of bacteria from fecal or skin bacteria enter into the bladder at the time of insertion of the urinary catheter(66).
Thos could be the patients own transient microflora or commensals. There is ascending infection from the urethral meatus through the urinary catheter , ie.
catheter-mucosa interface. There can also be spread of infection through the
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urinary tube intraluminally if there is exixting uropathogens in the uro bag or the collecting tube . Hence the catheter acts as a frequently manipulated foreign body on which pathogens are spread . It also appears that uroepithelial cells from catheterized patients are more receptive to binding of bacteria just prior to onset of infection (67). Approximately two-thirds (79% for gram-positive cocci and 54%
for gram-negative bacilli) of the uropathogens that cause CA-bacteriuria in patients with indwelling urethral catheters are extraluminally acquired (by ascension along the catheter-urethral mucosa interface), and one-third are intraluminally acquired (68). The causative uropathogen can be found in the urethra in up to 67% of women and 29% of men just prior to the development of CA-bacteriuria, which suggests that entry of uropathogens via the urethral route occurs more often in women than it does in men (60), which is a sex difference that is not seen in other studies. Further support for ex- traluminal ascension as the most common pathway for bacteria to gain entry into the bladder comes from a study that showed only 3 of 29 episodes of bacteriuria with gram-negative bacilli or enterococci occurred in patients with negative meatal cultures for these organisms (68). In addition, patients remain at increased risk of bacteriuria for at least 24 h even after removal of the catheter (69), which suggests that colonization of the urethra persists after the catheter is removed. The importance of the intraluminal pathway is associated with the number of times, closed drainage
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systems are breached.This is associated with UTI. Both animal and human studies have demonstrated that bacteria that enter the drainage bag are soon found in the bladder (70,71)
MICROBIOLOGY
Short term catheterization is usually by a single organism. (71). The most common organism isolated associated with short term cather is Escherichia . It comprises less than one-third of all isolates (72). Other organisms that cause Urinary infection include Enterobacteriaceae, such as Klebsiella species, Citrobacter species ,Serratia species. Enterobacter species, nonfermenters such as P. aeruginosa and gram-positive cocci, including coagulase-negative staphylococci and Enterococcus species are organism that cause urinary tract infection(69).
Short term catheterization is associated with urinary infection caused by P.
mirabilis, P. stuartii , Morganella morganii (74.) candiduria has been found in , 3%–32% of patients in short term catheterization (70). Long term catheterization is associated with chronic infection with polymicrobia. However they have associated urinary tract infections periodically from the pathogens that are already existing . This may persist for months(73). Pathogens like E. coli and K.
pneumonia amy persist in urine even if the urinary catheter is frequently changed.
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Howeve in patients whor required catheter for longer duration of time, pathogens such as P. mirabilis, P. stuartii , M. morganii,P. aeruginosa,and enterococci did not persist in the urine when the catheter was changed. There was a ten fold decrease in persistence of these organism with the change in catheterThe concentration of certain organisms decreases with change in catheter (76). These data suggest that the catheter is more important for persistence in the urinary tract ALTERNATIVE TECHNIQUES FOR ESTIMATING URINARY RETENTION
Several alternative techniques for estimating Urinary bladder volumen following retention have been reported such as clinical examinaiton by abdominal palpation and percussion, ultrasonography and radionuclide scan, (78). Clinical examination such as per abdominal palpation and percussion of the urinary bladder is non invasive and easy, but lacks accuracy. Radionuclide scan is not available at all settings, however accurate and expensive. There is also a need for experienced radiologist to perform a radioneucleotide scan (79).
ULTRASONOGRAPHY
Ultrasound of the urine bladder during the intrapartum period has been increasingly used in the evaluation of pregnant patients with urinary retention
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because it is fast,with no exposure to radiation,easy and non invasive (80) . Ultrasound is the only imaging modality without radiation hazards and is most commonly used to measure the volume of the bladder. (79) Most ultrasound centres have algorithms that are calculated automatically, for bladder volume estimation.However the results are subjective. Several methods to calculate bladder volume have been reported and this causes significant variations in estimation of bladder volume. (81)
Ultrasound has been implicated as the least invasive , easy option to measure unrinary blader wall thickness and bladder volume. The bladder wall has three layers on ultrasound .The detrusor muscle appears as a hypoechogenic layer between two hyperechogenic layers which represent the serosa and mucosa . The thickness of the three layers together can be considered as the bladder wall thickness according to some autors. Others , they used only the middle detrusor (81). Most studies considered using the anterior bladder wall by transabdominal ultrasound.In some studies , the posterior bladder wall has been used by transrectal or transvaginal ultrasound. Several studies have shown that there are no significant differences between the two. (81,82).
Ultrasound imaging quality and clarity depends on the frequency of the ultrasound waves used.The higher the frequency the better the resolution of the
47
image but the depth of penetration reduces. Oelke et al. (78) suggested that it is necessary to use high-frequency ultrasound arrays-7.5 MHz or higher for precise measurement of bladder wall thickness (BWT) and it should have enlargement function. Bladder wall thickness is volume dependent and the wall thickness decreases with increase in filling volume. Oelke et al.(78) found that the bladder wall thickness decreased rapidly during the first 250 ml of bladder filling in 9 volunteers with normal urodynamics . This led to the others to investigate bladder wall weight as a measure of bladder hypertrophy which should remain constant at different bladder volumes. For measuring bladder wall thickness, both two dimensional B-mode and three dimensional V-mode ultrasound can be used, Both have their merits and demerits.
ULTRASOUND ESTIMATED BLADDER WEIGHT
BWT/DWT is affected by filling volume. Therefore, its usefulness as a clinical tool becomes limited in everyday practice. Kojima et al (88) attempted to resolve this problem by calculating bladder weight. Transabdominal ultrasound measurements of intravesical volume and BWT were obtained (89). Assuming the bladder to be a sphere, the bladder wall volume was calculated by subtracting the intravesical volume from the total bladder volume, which includes the bladder wall. The ultrasound estimated bladder weight [UEBW] was obtained by
48
multiplying this parameter with the specific gravity. The UEBW of cadaveric bladders correlated significantly with the actual bladder weight (r = 0.970, p
<0.0001), and stable UEBW was observed in 16 patients measured repeatedly at filling volumes between 100 and 300 ml. Kojima et al (88) also reported greater mean UEBW in conditions that cause BOO, such as benign prostatic hyperplasia, prostate cancer and urethral stricture.
49
Figure 6: Transverse length and breadth of urinary bladder Sagittal height of urinary bladder
ACCURACY OF ULTRASONIC IMAGING
Ultrasonic imaging provides a possible alternative method for estimating bladder volume noninvasively. Kojima et al., (89) report, bladder volume could be accurately estimated with two-dimensional (2D) ultrasound by a transabdominal
50
or transvaginal approach . 2D scan volume estimates were based using ellipsoid or spherical equations to calculate the volume of a regular geometric organ shape (66).
Ultrasonography, is an interesting method because it is safe, reproducible, repeatable, noninvasive, cost-effective, painless.It demands little cooperation from the patient and, in most cases, is found to be accurate (84). Schoor RA, et al (85) reported the accuracy of bladder scanning appears to be inconclusive, particularly during the childbirth continuum (pregnancy, labour and post birth).
ladder scanner in maternity care has been recommended by some authors . Being catheterised increases the risk of urethral trauma, discomfort, urinary tract infection and negative psychological effects related to this invasive procedure (86).
Kessler TM, et al (87) found that in patients who had undergone prostrate surgery, that transabdominal ultrasound was accurate in the assessment of postvoid residual urine volume and was found to be quite useful. They found high correlation(r=0.98) between ultrasound estimation of post void residue and catheterization.
PARAMETERS AFFECTING ACCURACY OF ULTRASOUND
In a study consisting of 640 parturients, YIP et al found that the overall incidence
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of incidence of urinary retention was 14.6%(3). It was found that the mean duration of labour was longer(>800 minutes) in patients with post partum retention of urine. A possible mechanism is applied mechanical strength, which contributes to pelvic nerve damage leading to neurologic impairment of the bladder.
Birth weight of the baby have been evaluated as the cause for post partum urinary retention. However several studies have shown that birth weight of the baby does not increase the risk of post partum urinary retention (90).
The relationship of the fetal head to the maternal ishchial spines is the station of fetal head. If the vertex had crossed the ischial spines,it means that the largest diameter of the fetal head has passed the pelvic brim.
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Figure 7: station of fetal head per abdomen
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MATERIALS AND METHODS Research design
This was a observational cross sectional prospective study.
Study setting:
The study was approved by the Institutional Review Board of Christian Medical College and Hospital, Vellore. It was conducted between February 2018 and August 2019. Patients were recruited from the labour ward of the Department of Obstetrics and Gynaecology, Christian Medical College Vellore, following an informed consent. A total of 308 women who met the inclusion criteria were recruited for the study.
INCLUSION CRITERIA
Group 1:
Women requiring elective catheterization for caesarean section, or women with preeclampsia on Magnesium sulphate who also need elective catheterization
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Group 2:
Women who were catheterized before instrumental delivery and those with failed voluntary micturition with prolonged interval from the last void or with a palpable bladder
EXCLUSION CRITERIA
Women with multifetal pregnancies.
Women requiring urgent LSCS for fetal distress, abruptio placentae, placenta praevia with bleeding or impending scar dehiscence.
Sample size:
GROUP 1:
The required sample size to show a correlation of about 0.65 units in the urine volume between Ultrasound and actual bladder volume was found to be 211 women with 90% power and 5% level of
significance. Agreement of urine output also showed a similar sample size of about 210 women with 90% power and 5% level of
55
significance when the anticipated ICC was considered to be 0.65 units. Hence it was decided to study 215 women for the present study.
GROUP 2:
The required sample size to show a reduction of about 75% in unnecessary catheterization was found to be 196 women with 95%
confidence limits and 7% precision
Method:
This study was done over one and half years among women with term singleton pregnancies in the labour room of CMC hospital, Vellore. Women who got admitted in the labour room were given the patient information sheet and counseled about the study on admission. Women who fulfilled the inclusion criteria and who were planned for catheterization due to any reason, underwent ultrasound estimation of the bladder volume just before catheterization after taking the consent, following which the actual amount of the urine drained was measured.
Ultrasound scan was done to estimate bladder volume in women who fulfill the inclusion
56
criteria. Urinary bladder was drained by intermittent/ continuous catheterization within five minutes following ultrasound. Women who were planned for elective caesarean section were advised to void one hour prior to the ultrasound to avoid errors in ultrasound measurement due to over-distended bladder.
Ultrasound measurement was performed with the woman in semi recumbent position.
TOSHIBA FAMIO 30 ultrasound machine or GE LOGIQ-e, January 2013 ultrasound machine was used with 3.5hz transducer and the curvilinear probe was used to measure the bladder volume in split view: transverse and sagittal with the images frozen in split view. In the transverse view, the probe was adjusted to get the maximum longitudinal (L)and horizontal(W) diameter is measured. Then the probe was rotated 90 degrees and the height of the bladder was measured in the sagittal plane giving the antero posterior diameter(H). Then the total volume of the bladder was calculated using the prolate ellipsoid formula which was in built in the ultrasound machine.
MEASUREMENT:
Volume of bladder is calculated by Prolate ellipsoid formula:
½ ( length x breadth x height)
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Length : Maximum distance measured vertically in the Transverse axis Breadth: Maximum distance measured horizontally in Transverse axis Height : Maximum distance measured diagonally in Sagittal axis
Following this the bladder was catheterized using 14F /16F Foleys’s catheter or Nelaton catheter to drain the bladder following the ultrasound. The drained volume of urine was then measured using a graduated measuring cup.
Statistical Methods:
Data was summarized using mean (SD) or median (IQR) for continuous variables based on normality. Categorical data were expressed as number and percentage.
The demographical and clinical variable were presented seperately for the two groups . The agreement between the predicted and catheterized volumes was given using ICC (95 % CI) and weighted kappa (95% CI) .The consistency of the two methods was presented with Pearson's correlation and Lin's concordance correlation. The maximum allowable difference between the two methods was presented using limits of agreement (LoA) using the Bland-Altman technique. The relation of other variables with the difference of urine volume between the two methods were analysed using perason's correlation and ANOVA. All the analysis were performed with STATA IC/15.0 software
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Detailed diagrammatic Algorithm of the study
Women requiring elective catherization e.g
for caesarean section
Severe preeclampsia
Women who are catheterized for :
Instrumental delivery
Failed voluntary micturition and prolonged interval from the last void
Palpable bladder
Informed consent obtained
U/S estimation of bladder volume done
Catheterized volume of urine
measured
Proforma completed
Term singleton pregnancies
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RESULTS
A total of 308 patient were recruited for the study
Graph 1 : RANDOMISATION GROUPS
141 167
Group 1 Group 2
There were 141 women who were recruited under Group 1 There were 167 women who were recruited under Group 2
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Table 1: Demographic profile
a,mean (standard deviation)
The mean age of patients recruited in the study was 26.72 +/- 4.29 and the mean body mass index of women recruited in the study was 25.87 +/- 4.95.
TOTAL GROUP 1 GROUP 2
AGE a 26.72(4.29) 27.74(4.46) 25.85(3.95)
BODY MASS INDEX a
25.87(4.95) 26.94(5.51) 24.96(4.22)
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Graph 2 A: PARITY
Graph 2B:
b Number (percentage)
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Majority of patients in group1 were multigravida 149(48.37%) whereas majority of patients in group 2 were primigravida-140(83.83%)
Table 2:
PARITY b GROUP 1 GROUP 2 TOTAL
1 19(13.48) 140(83.83) 159(51.62)
2 107(65.89) 24(14.37) 131(42.53)
3 15(10.64) 3(1,80) 18(5.84)
TOTAL 141(100) 167(100) 308(100)
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Graph 3A: MEDICAL RISK FACTORS
Graph 3B
:
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Obesity was the major medical risk factor among the patients who were recruited in the study. However it was not statistically significant between the two
groups.(P-0.89) Table 3:
Medical risk factors
Group 1 n (%) Group 2 n(%) Total n(%) Thyroid disorders 11(21.15) 13(40.63) 24(28.57)
Obesity 30(57.69) 18(56.25) 48(57.14)
Seizure disorder 3(5.77) 1(3.13) 4(4.76)
Asthma 5(9.62) 1(3.13) 6(7.14)
Heart disease 2(3.85) 1(3.13) 3(3.57)
Renal failure 1(1.92) 0 1(1.19)
Autoimmune disorder
1(1.92) O 1(1.19)
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Graph 4A: OBSTETRIC RISK FACTORS
Previous LSCS was the major obstetric risk factor in group 1 and GDM was found to the highest in group 2
Graph 4B:
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Table 4:
OBSTETRIC RISK FACTORS
GROUP 1 n(%) GROUP 2 n(%) TOTAL n(%)
GDM 38(28.74) 42(35.90) 80(31.50)
HYPERTENSIVE DISORDERS
16(11.68) 12(10.34) 28(11.07)
PREVIOUS LSCS 118(86.13) 7(6.03) 125(49.41)
INFERTILITY 1(0.73) 9(7.76) 10(3.95)
IUGR 7(5.11) 5(4.31) 12(4.74)
APLA 2(1.46) 1(0.86) 3(1.19)
PROM 1(0.73) 16(13.79) 17(6.72)
FIBROIDS 0 2(1.72) 2(0.79)
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Table 5A:
Table 5B:
There were total of 120 patients who had history of previous cesarean section in group 1. Among these there were 11 Patients with more than one caesarean scar . PREVIOUS
ABDOMINAL SCAR
GROUP 1 N(%)
GROUP 2 N(%)
TOTAL N(%)
YES 120(84.40) 5(2.99) 125(40.26)
NO 21(15.60) 162(97.01) 184(59.74)
TOTAL 141(100) 167(100) 308(100)
GROUP 1
N(%)
GROUP 2
N(%)
TOTAL N(%)
ONE
CAESAREAN SCAR
109(90.76) 5(100) 114(91.13)
>1 SCAR 11(9.24) 0 11(8.87)
TOTAL 120(100) 5(100) 125(100)
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Graph 5A:
INDICATIONS FOR CATHETERIZATION
Group 1 included patients who were catheterized for elective reasons such as previous LSCS -120, monitoring of urine output in patients being treated for severe pre eclampsia -7, for patients in labour whose fetal head stations are high - 12and others whose urine output was monitored for various reasons-2. In this group, maximum number of patients had a previous LSCS with 11 out of 120 patients having more than one caesarean scar.
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Graph 5B:
Group 2 included women who were catheterized for emergency Caesarean sections and who underwent operative vaginal deliveries-44, prolonged duration of >4 hours from the time of last void-72 , and women who had a palpable
bladder-51. Majority of patients have been catheterized for being unable to void or prolonged period from last void-43.1%
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Table 6:
PERCUSSION OF BLADDER
GROUP 1 N(%)
GROUP 2 N(%)
TOTAL N(%)
DULL 141(100) 165(98.80) 306(99.35)
RESONANT 0 2(1.20) 2(0.65)
TOTAL 141(100) 167(100) 308(100)
Alternative clinical methods to assess urinary retention were to see if the bladder could be identified on percussion or if the bladder could be palpated clinically.
However, almost all patients except two were found to have dullness on
percussion. This could be due to the presence of amniotic fluid or the fetal head.
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Graph 6: PARAMETERS AFFECTING CLARITY OF ULTRASOUND
BMI was found to be the major cause for not having good clarity while
performing the ultrasound -28, followed by abdominal wall edema-21, and station of head being low-11 .
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Table 7:
NO CLARITY WHEN
ULTRASOUND PERFORMED
GROUP 1 N(%)
GROUP 2 N(%)
TOTAL N(%)
BMI 20(80.00) 8(29.63) 28(53.9)
LOW HEAD 0 11(40.74) 11(21.1)
ABDOMINAL WALL EDEMA
10(40.00) 11(42.31) 21(41.2)
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Table 8:
There were only 6 patients who were on epidural who were recruited for the study.
EPIDURAL GROUP 1
N(%)
GROUP 2 N(%)
TOTAL N(%)
YES 2(1.42) 4(2.40) 6(1.95)
NO 139(98.58) 163(97.60) 302(98.05)
141(100) 167(100) 308(100)
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Table 9:
AGREEMENT INDICES CALCULATED FOR PREDICTED AND CATHETERISED VOLUME OF URINE
CORRELATI ON
(P VALUE)
CONCORDANC E
(P VALUE)
BIAS (SD)
LoA ICC
(95%CI )
WEIGHTE D
KAPPA(S.E )
GROUP 1
0.85 (<0.001)
0.85 (<0.001)
4.20 (71.08)
-135, 143
0.92 (0.89,0.
94)
0.62 (0.068)
GROUP 2
0.89 (<0.001)
0.88 (<0.001)
7.55 (146.7 8)
-
280.14 ,
295.25
0.93 (0.91, 0.95)
0.67 (0.054)
Overall 0.90(<0.001) 0.89(<0.001) -6.020 (118.1 3)
-
237.55 ,
225.51
0.94 (0.93,0.
95)
0.69(0.043)
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According to this table, the concordance and correlation between the ultrasound prediction of bladder volume and catheterized volume in Group 1 was consistent and was found to be statistically significant. Bias in group 1 was found to be 4.20 with limits of agreement between -135 to +143. The intraclass correlation
coeffiecient was found to be 0.92(0.89,9.94) between the predicted urine volume by ultrasound and catheterized volumes which was in excellent agreement with each other(Rosner’s criteria). Weighted KAPPA was found to be 0.62 (0.068) which was in substantial agreement between the predicted ultrasound volume and catheterized volume(Landis and Koch criteria)
According to this table, the concordance and correlation between the ultrasound prediction of bladder volume and catheterized volume in Group 2 was consistent and was found to be statistically significant. Bias in group 2 was found to be 7.55 with limits of agreement between -280.14 to +295.25. The intraclass correlation coeffiecient was found to be 0.93(0.91,0.95) between the predicted urine volume by ultrasound and catheterized volumes which was in excellent agreement with each other(Rosner’s criteria). Weighted KAPPA was found to be 0.67(0.054) which was in substantial agreement between the predicted ultrasound volume and catheterized volume(Landis and Koch criteria)
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Hence overall, the concordance and correlation between the ultrasound prediction of bladder volume and catheterized volume was consistent and was found to be statistically significant. Bias overall was found to be -6.020 with limits of agreement between -237.55 to +225.51. The intraclass correlation
coeffiecient was found to be 0.94(0.93,0.95) between the predicted urine volume by ultrasound and catheterized volumes which was in excellent agreement with each other(Rosner’s criteria). Weighted KAPPA was found to be 0.69(0.043) which was in substantial agreement between the predicted ultrasound volume and catheterized volume(Landis and Koch criteria)
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Graph 7: CORRELATION BETWEEN THE DURATION OF LABOUR AND ACCURACY OF ULTRASOUND ESTIMATION OF BLADDER VOLUME
This scatter plot has duration of labour in hours on the x axis
The difference between the predicted volume by ultrasound and catheterized volume on the y axis.
It shows that there is no correlation between the duration of labour and the accuracy of ultrasound performed
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Graph 8: CORRELATION BETWEEN BIRTH WEIGHT AND ACCURACY OF ULTRASOUND ESTIMATION OF BLADDER VOLUME
This scatter plot has weight of the baby in kilograms on the x axis
The difference between the predicted volume by ultrasound and catheterized volume on the y axis.
It shows that the accuracy of ultrasound was not altered by the weight of the baby
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Graph 9:CORRELATION BETWEEN CERVICAL DILATATION AND ACCURACY OF ULTRASOUND ESTIMATION OF BLADDER VOLUME
This stock plot shows cervical dilatation in centimeters on the x axis The
difference between the predicted volume by ultrasound and catheterized volume on the y axis.It shows that the accuracy of ultrasound was not altered by the amount of cervical dilatation.
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Graph 10: CORRELATION BETWEEN DURATION OF RUPTURE OF MEMBRANES AND ACCURACY OF ULTRASOUND ESTIMATION OF BLADDER VOLUME
This scatter plot has duration of rupture of membranes in hours on the x axis .It is duration between the time of rupture of membranes(spontaneous/ARM) to the time when the ultrasound was performed.
81
The difference between the predicted volume by ultrasound and catheterized volume on the y axis.It shows that there is no correlation between the duration of rupture of membranes and the accuracy of ultrasound performed
82
Graph 11: CORRELATION BETWEEN STATION OF HEAD PER ABDOMEN AND ACCURACY OF ULTRASOUND ESTIMATION OF BLADDER
VOLUME
This stock plot shows station of head per abdomen on the x axis
The difference between the predicted volume by ultrasound and catheterized volume on the y axis.
It shows that the accuracy of ultrasound was not altered by the amount of cervical dilatation.
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Table 10:
URINE VOLUME BY
ULTRASOUND
GROUP 1 GROUP 2 TOTAL
<150ml 103(73.05) 78(46.71) 181(58.77)
151-300 27(19.15) 38(22.75) 65(21.10)
301-600 10(7.09) 28(16.77) 38(12.34)
>600ML 1(0.71) 23(13.77) 24(7.79)
TOTAL 141(100) 167(100) 308(100)
There are a total of 181 women who had predicted urine volume < 150 ml. As per definition, urine retention is > 150ml. Hence, it can be said that in 181(58.77%) unnecessary catheterizations could have been prevented.
In this study, these women were catheterized since it was an observational study and was in terms with the protocols followed in labour room.
84
Graph 12A: MODE OF DELIVERY
In group 2, the most common mode of delivery was found tobe operative vaginal delivery-41.3% . In group 1, the most common mode of delivery was found to be caesarean section-93%
Graph 12 B:
28.7
41.3
29.94
0 5 10 15 20 25 30 35 40 45
NORMAL OPERATIVE VAGINAL LSCS
GROUP 2
GROUP 2
85
Graph 13: Bland Altman plot:
This is a bland altman plot. X axis shows average between the predicted urine volume by ultrasound and catheterized volume.
Y axis shows the difference between the predicted urine volume by ultrasound and catheterized volume.
86
According to this plot, in volume < 150 ml, there was underestimation of urine volume by ultrasound compared to the catheterized volume of urine. In volume
>150 ml , the graph did not have a particular character and was scattered.
However the consistency of predicted urine volume by ultrasound and catheterized volume of urine was found to be good.
87
DISCUSSION
Urinary catheterization remains the gold standard for measurement of bladder volume. However it is invasive and not tolerated well by the patients. Currently there are no systematic and standard ways to assess urinary retention in pregnant women in labour. Ultrasound serves as a good alternative to measure bladder volume since it is non invasive, simple, and well tolerated by the patient.
Acute overdistension of the bladder causes ischaemia to post synaptic
parasympathetic fibres and cause damage to detrusor muscle. These patients were found to have covert retention post partum and might develop long term
complications. A large number of studies have been done to examine the
relationship between obstetric risk factors that might be associated to or cause for post partum urinary retention.
Epidural Analgesia
Labour analgesia is administered to the patient by many pharmacological and non pharmacological methods. One such method to provide relief for labour pain is by giving the patient Epidural analgesia. An epidural catheter is placed in the lumbar
88
vertebra(L3-L4) region and a continuous infusion of local anaesthetic with or without an additive is given to the patient. Epidural local anesthetics act on the sacral and lumbar nerve fibers, blocking the transmission of afferent and efferent nervous impulses from and to the bladder. The onset and the duration of the block would depend on the pharmacokinetic properties of the local anesthetic used. A Retrospective case control study was done by Roderick et al.The study intended to determine the incidence of overt post partum retention following a vaginal
delivery and to establish risk factors associated with it. 15,757 deliveries were included from 2001-2005. There were 120 time matched controls and 30 cases of overt post partum retention (OR 6.33,CI 2.01-19.96,P<0.001). At the beginning of the study it was decided to find the association of epidural analgesia and urinary retention. However only six patients who received epidural analgesia were included in the study. Taking into account minimal number of study patients on epidural, the effect of it on urinary retention was inconclusive.
Duration of labour
During normal labor, the presenting part of the fetus (head) exerts some amount of pressure on the pelvic soft tissues, pelvic floor and the pelvic soft tissues. When there is prolonged exertion of pressure there may be subsequent edema or
neuropraxia which leads to detrusor muscle dysfunction. This can lead to urinary
