How can urethral trauma be prevented during catheterisation. What are the risks of improper catheter balloon inflation. How does a novel safety device help prevent urethral injury. What are the key parameters for designing safer urethral catheter systems.

Understanding Urethral Catheterisation and Associated Risks

Urethral catheterisation is a common medical procedure performed on approximately 25% of hospitalized patients. While routine, this procedure carries risks, particularly for male patients. The most significant risk is urethral injury, which typically occurs when the catheter’s anchoring balloon is mistakenly inflated inside the urethra instead of the bladder.

Complications from improper catheterisation can be both short-term and long-term:

• Short-term complications: pain, bleeding, and acute urinary retention
• Long-term complications: urethral stricture disease, potentially requiring urethral reconstruction in severe cases

Investigating Urethral Strain Thresholds for Rupture

Prior to the study conducted by Davis et al., there was a lack of research demonstrating urethral strain thresholds for rupture during traumatic urethral catheterisation. The researchers aimed to investigate two key parameters:

1. Internal urethral diametric strain
2. Threshold maximum inflation pressure

These parameters were studied to determine at what point urethral rupture occurs during inadvertent inflation of a catheter anchoring balloon in the urethra.

Methodology of the Study

The researchers employed the following methods:

• Used 21 ex vivo porcine models
• Inflated 16 Fr catheters in the bulbar urethra
• Characterized and graded urethral trauma using retrograde urethrography
• Correlated urethral rupture with internal urethral diametric strain (%) and maximal urethral pressure threshold values (kPa)
• Calculated internal urethral diametric strain by averaging urethra luminal diameter proximal and distal to the traumatized site, and maximum luminal diameter at the traumatized site

Developing a Novel Safety Device for Catheterisation

Based on the parameters identified in their study, the researchers designed and evaluated a novel safety device. This device was engineered to prevent urethral trauma, even in cases of inadvertent balloon inflation in the urethra.

Testing the Safety Device

The researchers conducted comparative tests using:

• A standard syringe
• A prototype safety-syringe

These tests were performed on the bulbar urethras of seven fresh male cadavers. The key difference in the syringes was the mechanism of inflation:

• Standard syringe: The plunger was depressed until opposing resistance pressure from the urethra prevented further inflation of the anchoring balloon.
• Prototype safety-syringe: The plunger was depressed until sterile water in the syringe decanted through an activated safety threshold pressure valve.

Key Findings: Urethral Rupture Thresholds

The study revealed critical thresholds for urethral rupture:

• Internal urethral diametric strain: >40%
• Maximum inflation pressure: >150 kPa

These findings were consistently observed in the porcine models through retrograde urethrography.

Human Urethral Threshold Inflation Pressure

In human cadaver tests, the researchers found:

• Mean maximum human urethral threshold inflation pressure to activate the safety prototype syringe pressure valve: 153±3 kPa
• Mean maximum inflation pressure using the standard syringe: 452±188 kPa

The difference between these pressures was statistically significant (p<0.001), demonstrating the effectiveness of the safety device in preventing excessive pressure buildup.

Implications for Safer Catheter Design

The study’s findings have significant implications for the design of safer urethral catheter systems. By identifying the critical parameters of internal urethral diametric strain and threshold maximum inflation pressures, manufacturers can develop catheter systems with lower intrinsic threshold inflation pressures.

This approach could significantly reduce the risk of urethral trauma during catheterisation, particularly in cases where the balloon is inadvertently inflated in the urethra instead of the bladder.

Clinical Implementation of the Safety Device

Following the success of their porcine and cadaver studies, the researchers took further steps to validate their findings:

• Conducted additional tests on human male-to-female transgender urethral models
• Implemented the safety device into clinical practice at Tallaght Hospital, Dublin, Ireland

This successful transition from bench research to clinical application represents a significant advancement in patient safety for those requiring urethral catheterisation.

Future Directions and Potential Impact

The development and implementation of this safety device could have far-reaching implications for urological care. Some potential areas of impact include:

• Reduced incidence of urethral trauma during catheterisation
• Decreased need for urethral reconstruction surgeries
• Improved patient comfort and safety during hospital stays
• Potential cost savings for healthcare systems by preventing complications

Further research may focus on:

• Long-term clinical outcomes of patients catheterized using the safety device
• Adaptation of the safety mechanism for different catheter types and sizes
• Implementation of similar safety principles in other medical devices

Educating Healthcare Professionals on Safer Catheterisation Techniques

While technological advancements like the safety syringe are crucial, educating healthcare professionals on proper catheterisation techniques remains essential. Key points for training programs might include:

• Proper identification of anatomical landmarks
• Techniques for gentle catheter insertion
• Recognition of resistance and when to stop advancing the catheter
• Proper balloon inflation procedures
• Signs of potential urethral trauma and immediate interventions

By combining improved technology with comprehensive education, the medical community can significantly reduce the incidence of urethral trauma during catheterisation.

The Role of Simulation in Training

Simulation-based training could play a crucial role in improving catheterisation skills among healthcare professionals. Benefits of simulation training include:

• Risk-free environment for practice
• Opportunity to experience and manage rare complications
• Immediate feedback on technique
• Standardization of training across institutions

Implementing simulation training programs could complement the use of safety devices, further reducing the risk of urethral trauma during catheterisation.

Addressing Patient Concerns and Improving Communication

Improving patient safety during catheterisation also involves addressing patient concerns and enhancing communication. Healthcare providers should:

• Explain the catheterisation procedure to patients in clear, understandable terms
• Discuss the reasons for catheterisation and expected duration
• Address any patient anxieties or questions
• Provide information on potential discomfort and how it will be managed
• Educate patients on signs of complications to report

Clear communication can help reduce patient anxiety, improve cooperation during the procedure, and enhance early detection of any complications.

Patient Education Materials

Developing comprehensive patient education materials can support verbal explanations and reinforce important information. These materials might include:

• Illustrated guides explaining the catheterisation procedure
• Information on proper catheter care for patients with indwelling catheters
• Frequently asked questions about catheterisation
• Contact information for medical support in case of concerns

By empowering patients with knowledge, healthcare providers can create a collaborative approach to catheter care and complication prevention.

Expanding Research to Diverse Patient Populations

While the initial research focused on male urethras, expanding studies to include diverse patient populations could provide valuable insights. Areas for further investigation might include:

• Catheterisation risks and safety measures for female patients
• Age-related differences in urethral structure and implications for catheterisation
• Impact of various medical conditions on catheterisation risks
• Cultural and ethnic variations in urethral anatomy and catheterisation outcomes

Broadening the scope of research can help ensure that safety measures and guidelines are applicable to a wide range of patients, improving overall care quality.

Collaborative Research Initiatives

Encouraging collaborative research initiatives between different medical specialties and institutions could accelerate progress in catheterisation safety. Potential collaborations might involve:

• Urologists and emergency medicine specialists
• Biomedical engineers and clinical practitioners
• Nursing researchers and urology departments
• International partnerships to study global variations in catheterisation practices

Such collaborations could lead to more comprehensive solutions and faster implementation of safety measures across diverse healthcare settings.

Integrating Technology for Improved Catheterisation Safety

Beyond the safety syringe, other technological advancements could further enhance catheterisation safety. Potential innovations might include:

• Smart catheters with sensors to detect incorrect placement
• Augmented reality systems to guide catheter insertion
• Machine learning algorithms to predict catheterisation difficulties based on patient data
• Telemedicine platforms for remote guidance during difficult catheterisations

Embracing technological innovations could revolutionize the field of urethral catheterisation, making it safer and more efficient.

Challenges in Technology Adoption

While technological solutions offer great promise, their adoption in clinical practice may face challenges such as:

• Cost of implementation
• Resistance to change among healthcare professionals
• Need for additional training
• Regulatory approval processes

Addressing these challenges proactively can help smooth the path for integrating new technologies into standard catheterisation procedures.

Preventing Urethral Trauma During Catheterisation

Authors:

^*Niall F. Davis,^1,2
Rory O’C. Mooney,²
Conor V. Cunnane,²
Eoghan M. Cunnane,²
John A. Thornhill,¹
Michael T. Walsh²

1. Department of Urology, Tallaght Hospital, Dublin, Ireland
2. Centre for Applied Biomedical Engineering Research, Materials and Surface Science Institute, University of Limerick, Castletroy, Ireland
*Correspondence to: [email protected]

Citation:

EMJ Urol. 2017;5[1]:60-61. Abstract Review No. AR19.

Keywords:

Urethral trauma,
urethral catheterisation,
urethral rupture,
urethral injury,
urethral catheter,
safety device,
safety syringe

Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.

Urethral catheterisation is a routine task that is frequently performed within a healthcare setting. Almost 25% of hospitalised patients are catheterised during their inpatient stay.¹ Urethral injury typically occurs in men when the catheter’s anchoring balloon is inadvertently inflated inside the urethra.² Short-term complications include pain, bleeding, and acute urinary retention.² Urethral rupture can lead to the long-term complication of urethral stricture disease and may require urethral reconstruction in severe cases.²

There are currently no studies that demonstrate urethral strain thresholds for rupture during traumatic urethral catheterisation. Our aim was to investigate internal urethral diametric strain and threshold maximum inflation pressure as parameters for urethral rupture during inadvertent inflation of a catheter anchoring balloon in the urethra. In addition, we also designed and evaluated a novel safety device with the inability to cause urethral trauma, despite inadvertent balloon inflation in the urethra based on these parameters.

Inflation of a urethral catheter anchoring balloon was performed in the bulbar urethra of 21 ex vivo porcine models using 16 Fr catheters. Urethral trauma was characterised and graded with retrograde urethrography. Urethral rupture was correlated with internal urethral diametric strain (%) and maximal urethral pressure threshold values in kilopascals (kPa). Internal urethral diametric strain was calculated by averaging urethra luminal diameter proximal and distal to the traumatised site, and maximum luminal diameter at the traumatised site. Urethral catheters were then inflated in the bulbar urethras of seven fresh male cadavers using a standard syringe and a prototype safety-syringe prototype safety-syringe (Figure 1). The plunger of the standard syringe was depressed until opposing resistance pressure generated by the urethra prevented further inflation of the anchoring balloon. The plunger of the prototype safety-syringe was depressed until sterile water in the syringe decanted through an activated safety threshold pressure valve (Figure 1).

Figure 1: The prototype syringe used to determine urethral resistance pressure. The safety valve (arrow) is activated at threshold resistance pressure, allowing fluid to vent out of the activated valve.

Retrograde urethrography demonstrated that porcine urethral rupture consistently occurred at an internal urethral diametric strain >40% and a maximum inflation pressure >150 kPa (Figure 2). The mean±standard deviation maximum human urethral threshold inflation pressure required to activate the safety prototype syringe pressure valve was 153±3 kPa. In comparison, the mean maximum inflation pressure was significantly greater using the standard syringe than the activated prototype syringe (452±188 kPa, [p<0.001]).

Figure 2: Maximum catheter balloon/urethral pressure and internal diametric strain recorded for each of the 21 urethral samples tested.
This figure clearly demonstrates a safety cut-off of >40% internal urethral diametric strain and/or maximum balloon pressure cut-off of 150 kPa before urethral rupture (red dashed lines). Open circles indicate ruptured urethral samples. Filled circles indicate unruptured samples.

Internal urethral diametric strain and threshold maximum inflation pressures are important parameters for designing a safer urethral catheter system with lower intrinsic threshold inflation pressures. We have validated our porcine and cadaver findings in human male-to-female transgender urethral models and have recently implemented our safety device into clinical practice in Tallaght Hospital, Dublin, Ireland for patients requiring urethral catheterisation. This transition of a safety device from bench to bedside was commended during my presentation during March 2017, held at the European Association of Urology (EAU) congress, hosted in London, UK.

References

Chenoweth C, Saint S. Preventing catheter-associated urinary tract infections in the intensive care unit. Crit Care Clin. 2013;29(1):19-32.
Davis NF et al. Incidence, Cost, Complications and Clinical Outcomes of Iatrogenic Urethral Catheterization Injuries: A Prospective Multi-Institutional Study. J Urol. 2016;196(5):1473-7.

Misplaced Catheter Causes Significant Urological Damage

This case involves a misplaced catheter resulting in serious, long-term urological damage.

On the date of the incident in question, the patient was admitted to the hospital undergo a hip replacement. Pre-surgery, the patient was anaesthetized, and the nurse attempted to place a Foley catheter. However, the Foley catheter balloon was inflated in the patient’s urethra instead of his bladder. The balloon remained in the urethra for hours, despite not producing a good return of urine, and the patient did not recieve a urology consultation. This misplacement necessitated a surgical procedure to implant a temporary suprapubic tube and additional surgery of the urethra. Due to this misplacement, the patient ultimately spent multiple days in intensive care and suffered permanent disability and disfigurement.

Question(s) For Expert Witness

1. Are you able to address standard of care/ongoing complications as it relates to using a Foley catheter improperly?

Expert Witness Response E-014220

I am very familiar with current standard of care for Foley catheter placement and management (especially for inpatients) and catheter related complications, such as trauma related complications and catheter associated UTIs (CAUTIs). I’m familiar with risk factors associated with catheter related complications (i.e. traumatic catherizations) which include but not limited to prior lower urinary tract surgery/procedure (ex. TURP, RRP/RALP etc), presence of urinary tract device, such as sphincter or sling, and prior lower urinary tract trauma or infections. In 2012 I was a member of a multidisciplinary committee at my institution addressing catheter associated complications, such as UTIs and traumatic injury due to placement of Foley catheter. Our committee’s findings led to significant changes in urethral catheter management in inpatients. Protocols were created for placement and subsequent management of Foley catheters for all inpatients. This included, specific to minimizing risk of traumatic catheterization, that the catheter balloon should not be inflated until the catheter is completely in and there is return of urine. Also, if the patient has risk factors for catheter related complications (as described above), developed blood per urethra upon initial attempts to catheterize, or requires a Coude cath (specialized catheter) Urology should be consulted. These are typically patients on trauma service, ICU/CCU, and surgical services. This often involves urgent or semi-urgent placement of a Foley catheter by a nurse or intern/junior resident in the ER, trauma unit, resuscitation bay, ICU or operating room. The malposition is not recognized for hours or days (and sometimes week(s)) later. The subsequent history usually involves blood/urine bypassing around the catheter and poor drainage/urine output via catheter. Significant number of these patients has encountered long term sequelae from the injury due to the inflation of the balloon within the urethra. This injury inevitably leads to a urethra stricture which typically requires treatment either endodcopically, i.e. urethral dilation and/or DVIU (incising the stricture) or surgical repair/reconstruction, what is known as urethroplasty.

Placement, replacement and care of the Foley catheter.

Structure of the bladder

Placement of a Foley catheter.

Hygiene procedures must be carried out before insertion of the catheter.

The clinician should wash the patient’s hands and perineum with soap and water, disinfect with an antiseptic, and wear sterile gloves. Prepare the catheter (take with sterile tweezers, treat with a lubricant if necessary).

Female catheter insertion procedure:

Lying on your back, bend and spread your legs.

After parting the labia and finding the opening of the urethra, carefully insert the catheter. As soon as urine has gone through the catheter, you should stop.

After that, through one of the passages at the outer end of the catheter, inject sterile water with a syringe in a volume sufficient to inflate the balloon. Then attach the urine collection bag to the outer end. It is necessary to ensure that the bag is always below the level of the belt in order to avoid backflow of urine through the catheter.

Catheter insertion procedure for men:

Catheter insertion is more difficult for men. Since the urinary canal is longer and has physiological constrictions. The patient needs to lie on his back and slightly bend his knees, relax, the catheter is inserted into the urethra slowly and smoothly, with rotational movements, clamping the catheter with 5 and 4 fingers of the right hand, and first the genital organ must be held vertically, and then tilted down. Carefully advance the catheter. The presence of urine indicates that the catheter is placed correctly.

For children:

When placing a catheter, it is necessary to ensure the psychological comfort of the child.

Disinfect the genital area twice and wrap it with a sterile drape. Lubricate the end of the catheter, such as Vaseline.

Do not force the catheter if an obstruction is felt – this can damage the urethra.

The procedure for inserting the catheter is similar to that for adults, but the insertion depth is less because the urethra is shorter.

Urinary catheter care:

Wash the area around the catheter with soap and water several times a day to avoid irritating the infection. Do this after every bowel movement. Women are washed from front to back.

Drain the bag in time, keeping it below the level of the bladder to avoid urine flowing back into the catheter.

Change of catheter:

In case of normal urine outflow, the catheter is changed according to the recommendation of the doctor and instructions for use of the catheter.

Silicone has a shelf life of up to 30 days, latex up to 7 days, silicone with silver up to 90 days.

Never pull on the catheter. Disconnect the catheter only for rinsing or replacing it, as well as emptying the urinal.

Cases when you need to see a doctor:

– There are pains in the abdomen, flakes and blood in the urine.

— Urine is leaking from under the catheter.

– Urine outflow stopped.

Reasons for leaking urine:

catheter too thin, balloon not inflated enough, catheter or urinal tube kinked, catheter blocked.

Reasons for not passing urine:

a kink in the catheter or tube of the urinal,

insufficient fluid intake in the body (increase the amount of fluid consumed),

urinal is fixed too high (lower it below the level of the bladder),

blockade of the catheter,

impaired renal function (anuria) when the patient’s condition worsens.

Urinary catheters are flushed as directed by a physician:

Warm saline is used for flushing. If sediment or flakes appear in the urine, the catheter is washed with a solution of furacilin, as well as miramistin or chlorhexidine solution. For washing, Jeanne’s syringe is used.

Foley catheter

FAQ

When and why is intermittent catheterization recommended?

Intermittent catheterization is an effective and safe urinary diversion method that offers patients independence and significantly improves quality of life. In recent years, intermittent catheterization has become the preferred method for managing patients with neurogenic bladder dysfunction, paraplegia, diseases such as spina bifida or multiple sclerosis.

The choice of method of intermittent catheterization is carried out only after this method is recommended by the doctor in each case. Catheterization is carried out by emptying the bladder at regular intervals with disposable catheters.

How is intermittent catheterization performed in children?

Children with neurogenic bladder dysfunction may be catheterized by a parent or healthcare professional, always using asepsis. Parents should ask their doctor or medical professional who will explain and demonstrate the correct catheterization procedure. Only by carefully preparing you can be sure that you are performing the catheterization procedure correctly.

For infants and small children, the following sizes are generally used: 2.0-2.7 mm (Ch06-Ch08).

How many times a day should the bladder be catheterized?

Normal bladder emptying frequency is approximately 56 times a day. The frequency of catheterizations depends on the individual and factors such as how much you drink, medication, etc. Your healthcare provider can recommend how often you need to catheterize your bladder. You can determine for yourself when and how it will be best for you to carry out catheterization.

How much liquid should I drink every day?

This may vary depending on how active you are. You should aim to drink about 1.5-2 liters of fluid per day. Try to avoid drinks that contain caffeine, such as tea or coffee.

What should I do if I have difficulty inserting a catheter?

Sit in a comfortable position, try to relax and wait a while before performing the catheterization procedure. If you are unable to insert the catheter on your own, contact your healthcare provider.

What if I have difficulty removing the catheter?

Try not to worry and wait a while before trying again.