Characterisation of human urethral rupture thresholds for urinary catheter inflation related injuries.

Data on urethral catheter related injuries is sparse. In this study we aimed to characterise urethral diametric strain and urinary catheter inflation pressure thresholds that precede human urethral trauma during urethral catheterisation (UC). Human urethras were obtained from patients undergoing male to female gender reassignment surgery [(n = 9; age 40 ±â€¯13.13 (range: 18-58)) years]. 12Fr urinary catheters were secured in the bulbar urethra and the catheter's anchoring balloon was inflated with a syringe pump apparatus. Urethral diametric strain and balloon pressure were characterised with video extensometry and a pressure transducer respectively. Immunohistochemistry, Masson's trichrome and Verhoeff-Van Gieson stains evaluated urethral trauma microscopically. Morphological characterisation of the urethral lumen was performed by examining non-traumatised histological sections of urethra and recording luminal area, perimeter and major/minor axis length. Tearing (n = 3) and rupture (n = 3) of the urethra were observed following catheter balloon inflation. The threshold for human urethral rupture occurred at an external urethral diametric strain ≥ 27% and balloon inflation pressure ≥ 120kPa. Significant relationships were identified between urethral wall thickness and the level of trauma induced during catheter balloon inflation (p = 0.001) and between the pressure required to inflate the catheter balloon and the length of the major axis of the urethral lumen (p = 0.004). Ruptured urethras demonstrated complete transection of collagen, elastin and muscle fibres. In conclusion, urethral rupture occurs at an external urethral diametric strain ≥ 27% or with balloon inflation pressures ≥ 120 kPa. Incorporation of these parameters may be useful for designing a safety mechanism for preventing catheter inflation related urethral injuries.

Attitudes among junior doctors towards improving the transurethral catheterisation process.

OBJECTIVES: To evaluate the subjective opinions of junior doctors on their adequacy of training and confidence levels for performing transurethral catheterisation (TUC) and to investigate their subjective interest in a 'safety mechanism' that would eliminate the potential for urethral trauma during TUC. METHODS: An anonymous online survey was emailed to all interns that had a documented email address on the Royal College of Surgeons Ireland registry (2012-2013). The survey consisted of eight questions pertaining to TUC of male patients. RESULTS: The survey was delivered to 252 email addresses and the response rate was 52% (130/252). The vast majority (99%; n = 128) of interns felt confident inserting a transurethral catheter independently and 73% (n = 95) subjectively received appropriate training for catheterising male patients. The incidence of trauma after mistakenly inflating the catheter's anchoring balloon in the urethra was 3% (n = 4). The majority (90%; n = 116) of respondents were interested in a safety mechanism for preventing urethral trauma and 71% (n = 92) felt that a safety mechanism for urethral trauma prevention should be compulsory for all transurethral catheterisation among male patients. CONCLUSION: Despite pre-emptive training programmes, it appears that iatrogenic urethral trauma secondary to TUC remains a persistent morbidity in healthcare settings. Designing a safer transurethral catheter may be necessary to eliminate the risk of unnecessary urethral trauma in patients.