What are the risks of intra-urethral Foley catheter balloon inflation in spinal cord-injured patients. How can urethral trauma be prevented during catheterisation. What are the key parameters for designing safer urethral catheter systems. How effective is a novel safety device in preventing urethral injury.

Understanding Urethral Catheterisation and Associated Risks

Urethral catheterisation is a common medical procedure, with nearly 25% of hospitalized patients requiring catheterization during their stay. However, this routine task carries potential risks, particularly for male patients. One of the most significant dangers is urethral injury, which typically occurs when the catheter’s anchoring balloon is accidentally inflated inside the urethra instead of the bladder.

The consequences of such an error can be severe, including:

• Immediate pain and discomfort
• Bleeding
• Acute urinary retention
• Long-term complications like urethral stricture disease
• In severe cases, the need for urethral reconstruction

Investigating Urethral Strain Thresholds and Rupture Parameters

To address the lack of studies demonstrating urethral strain thresholds for rupture during traumatic catheterisation, researchers conducted a comprehensive investigation. The study aimed to explore two critical parameters:

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

These factors were examined to determine their role in urethral rupture during inadvertent balloon inflation in the urethra. The research utilized ex vivo porcine models and fresh male cadavers to gather data and develop insights into safer catheterisation practices.

Methodology and Experimental Setup

The study employed the following methodological approach:

• Inflation of 16 Fr catheter anchoring balloons in the bulbar urethra of 21 ex vivo porcine models
• Characterization and grading of urethral trauma using retrograde urethrography
• Correlation of urethral rupture with internal urethral diametric strain (%) and maximal urethral pressure threshold values (kPa)
• Calculation of internal urethral diametric strain by averaging urethra luminal diameter proximal and distal to the traumatized site, and maximum luminal diameter at the traumatized site
• Inflation of urethral catheters in the bulbar urethras of seven fresh male cadavers using a standard syringe and a prototype safety-syringe

Key Findings: Urethral Rupture Thresholds

The research yielded crucial insights into the conditions under which urethral rupture occurs:

• Porcine urethral rupture consistently occurred at an internal urethral diametric strain greater than 40%
• Rupture was also associated with a maximum inflation pressure exceeding 150 kPa

These findings establish clear safety thresholds for catheter inflation, providing a foundation for developing safer catheterisation techniques and devices.

Introducing a Novel Safety Device for Catheterisation

Based on the research findings, the team designed and evaluated a novel safety device aimed at preventing urethral trauma during catheterisation. This innovative prototype safety-syringe incorporates a unique feature:

• A safety threshold pressure valve that activates when a specific resistance pressure is reached
• Upon activation, the valve allows sterile water in the syringe to decant, preventing over-inflation of the catheter balloon

Comparing Standard and Safety Syringes

The study compared the performance of the prototype safety-syringe with a standard syringe:

• The mean maximum human urethral threshold inflation pressure required to activate the safety prototype syringe pressure valve was 153±3 kPa
• In contrast, the mean maximum inflation pressure using the standard syringe was significantly higher at 452±188 kPa (p<0.001)

These results demonstrate the potential of the safety-syringe to prevent excessive pressure application during catheter balloon inflation, thereby reducing the risk of urethral trauma.

Implications for Clinical Practice and Patient Safety

The findings of this research have significant implications for improving patient safety during urethral catheterisation:

1. Establishment of safety parameters: The study provides clear thresholds for internal urethral diametric strain and maximum inflation pressure, which can guide the development of safer catheterisation protocols.
2. Design of safer catheter systems: By understanding the critical parameters for urethral rupture, manufacturers can develop catheter systems with lower intrinsic threshold inflation pressures.
3. Implementation of safety devices: The prototype safety-syringe demonstrates the potential for innovative tools to prevent urethral trauma during catheterisation.

From Bench to Bedside: Clinical Implementation of the Safety Device

The research team has taken significant steps to translate their findings into clinical practice:

• Validation of findings: The porcine and cadaver study results were further validated using human male-to-female transgender urethral models.
• Clinical implementation: The safety device has been introduced into clinical practice at Tallaght Hospital, Dublin, Ireland, for patients requiring urethral catheterisation.
• Recognition: The transition of this safety device from bench to bedside was commended during a presentation at the European Association of Urology (EAU) in March 2017.

Future Directions and Ongoing Research

While the current study provides valuable insights and a promising safety device, there are several areas for future research and development:

• Long-term efficacy studies: Conducting longitudinal studies to assess the long-term impact of the safety device on reducing catheter-related complications.
• Adaptation for different patient populations: Investigating whether the safety parameters and device design need to be adjusted for specific patient groups, such as pediatric or geriatric populations.
• Integration with existing catheter systems: Exploring ways to incorporate the safety mechanism into a wide range of catheter designs and sizes.
• Training and education: Developing comprehensive training programs for healthcare professionals to ensure proper use of the safety device and adherence to safe catheterisation practices.

Addressing Challenges in Catheter-Related Urethral Trauma Prevention

Despite the promising results of this study, several challenges remain in preventing catheter-related urethral trauma:

Variability in Urethral Anatomy

Individual variations in urethral anatomy can affect the risk of trauma during catheterisation. How can catheter designs and safety devices account for these differences?

• Developing adjustable safety thresholds based on patient-specific factors
• Incorporating imaging guidance or sensing technologies to adapt to individual anatomies
• Creating comprehensive guidelines for catheter selection based on patient characteristics

Training and Skill Development

Even with safety devices, proper technique and skill are crucial for preventing urethral trauma. What strategies can be employed to enhance healthcare provider proficiency in catheterisation?

• Implementing simulation-based training programs
• Developing virtual reality tools for practicing catheterisation techniques
• Establishing regular skill assessments and refresher courses for healthcare professionals

Addressing Special Populations

Certain patient groups, such as those with spinal cord injuries or congenital urological abnormalities, may be at higher risk for catheter-related complications. How can catheterisation protocols be tailored to these populations?

• Conducting focused research on high-risk patient groups
• Developing specialized catheter designs and safety mechanisms for specific conditions
• Creating targeted education materials for patients and caregivers in high-risk categories

By addressing these challenges and continuing to innovate in catheter design and safety mechanisms, the medical community can significantly reduce the incidence of urethral trauma during catheterisation, improving patient outcomes and quality of life.

The Role of Technology in Advancing Catheterisation Safety

As medical technology continues to evolve, there are numerous opportunities to further enhance the safety and efficacy of urethral catheterisation:

Smart Catheter Systems

How can emerging technologies be integrated into catheter design to prevent urethral trauma?

• Pressure-sensing catheters that provide real-time feedback during insertion and balloon inflation
• Artificial intelligence-powered systems that guide catheter placement and alert to potential complications
• Biodegradable materials that reduce the risk of long-term complications from catheter use

Telemedicine and Remote Monitoring

Can telemedicine platforms be leveraged to improve catheter management and reduce complications?

• Remote monitoring systems for long-term catheter users to detect early signs of infection or obstruction
• Telementoring programs to provide real-time guidance for complex catheterisation cases
• Virtual follow-up consultations to assess catheter function and patient comfort

Data Analytics and Predictive Modeling

How can big data and predictive analytics contribute to safer catheterisation practices?

• Analyzing large-scale patient data to identify risk factors for catheter-related complications
• Developing predictive models to anticipate and prevent potential catheterisation issues
• Creating personalized catheter management plans based on individual patient profiles and historical data

By embracing these technological advancements and continuing to refine catheterisation techniques and safety devices, the medical community can significantly reduce the incidence of urethral trauma and improve overall patient care in this essential area of medical practice.

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.

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 can 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?

The normal frequency of emptying the bladder 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 fluid should you 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. Coughing can sometimes help insert or remove a catheter.

Are there any signs or symptoms I should be aware of?

Don’t wait until your bladder is full. The following symptoms may indicate that your bladder is too full:

• tense and swollen lower abdomen,
• headache,
• feeling of heat and sweating.

What should I do if urine does not come out of the catheter?

If urine does not come out through the catheter, remove it and try a new one. Make sure the catheter is in the bladder. If you feel that your bladder is still full, check with your doctor.

Possible complications of intermittent catheterization

One of the most common complications of catheterization is urinary tract infection. There may also be blood in the urine, bleeding from the urethra, or difficulty inserting a catheter. If you have any of these signs, contact your doctor.

Other tips

The following is a list of symptoms that may indicate a urinary tract infection:

• burning sensation,
• fever,
• fever,
• bad smell of urine .

If you have any of these signs, contact your doctor.

Placement, replacement and care of the Foley catheter.

The structure of the bladder

Placement of the Foley catheter.

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

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

Catheter insertion procedure for women:

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