Objectives

Standardise the variation in practice of using lignocaine gel and plain lubricating gel for female urethral catheterisation in the Emergency Department.

Methods

A randomised double blind study was carried out at two Sydney hospital Emergency Departments. Sixty two alert, cooperative adult female patients were recruited and scored procedural pain on Visual Analogue Scales (VAS). 

Outcomes

Lignocaine gel is both clinically and statistically superior at reducing procedural pain in female urethral catheteristion when compared to plain lubricant; mild compared to moderate pains scores respectively.

Measures are being used to change practice for the majority of nurses who are currently using plain lubricant.

To standardise on either of the two current practices: Lignocaine gel or plain lubricant gel for reducing the procedural pain of female urethral catheterisation in the Emergency Department.

There is currently significant variation and conflict with the use of lignocaine gel and plain lubricant gel in New South Wales Emergency Departments for female urethral catheterisation.

Plain lubricant or lignocaine gel is applied directly to the catheter prior to insertion to reduce friction and stretching of the urethra which causes procedural pain.

Some studies have shown that lignocaine gel (both a lubricant and a topical anaesthetic) is better than plain lubricant. However plain lubricant gel is almost exclusively used in female urethral catheterisation since there is a misconception that less pain is involved in female urethral catheterisation, because the female urethra is shorter and less tortuous than the male urethra. Lignocaine gel is always used in male urethral catheterisation.

A randomised double blind trial was performed between April 2005 and December 2005, to determine whether lignocaine gel was better than plain lubricant gel at relieving the procedural pain of female catheterisation in the Australasian Emergency Department (ED) setting.

The study was carried out at two hospitals; an urban district inner western Sydney hospital and south western Sydney major trauma referral centre. Approval was given by the respective hospital human research ethics committees.

The study involved adult female ED patients and permanent ED nursing staff, as the majority of urethral catheterisations are performed by nursing staff.

ED nursing staff, were trained on the study protocol, with on going reminders during the study period to reduce selection bias. A roster of those approved to carry out the study formalised the procedure to minimise any protocol violations. There was no change in the urethral catheterisation technique except nurses were instructed to use 14 French gauge catheters whenever possible.

ED patients were females over eighteen years of age. Patients with altered mental state, decreased visual acuity preventing completion of pain charts, currently pregnant, or with allergies to study gels were excluded.

The primary outcome measure was procedural pain scored by the patient on a Visual Analogue Scale (VAS). The VAS has established validity and reliability (Todd et al. 1996).

A minimum sample size of forty four patients (twenty two in each group) was calculated assuming standard 5% statistical significance level and 90% power to detect a minimum difference of 10mm of the mean procedural pain score between the two groups, with a standard deviation of 10mm. Control group estimates of procedural pain for catheterisation was based on previous studies (Tanabe et al. 2004).

To allow for failed catheterisations and protocol violations the study aimed to recruit sixty patients.

The ED nursing staff recruited female ED patients requiring urethral catheterisation (indication for catheterisation was independent of this study) and obtained written consent.

For each recruited patient a study pack from a supply on the ED catheter trolley was used. The study packs contained all study documentation and one of the study gels. Randomisation of the study pack was performed by the hospital pharmacy.

A ED nurse not performing the urethral catheterisation opened the study pack and dispensed the enclosed gel (not disguised) in the usual amount onto the sterile catheter tray without revealing the gel type to either the patient or the nurse performing the procedure, hence blinding both.

The patient was asked to rate any pre-procedural pain on a VAS prior to catheterisation and then rate post-procedural pain following urethral catheterisation on a second VAS as soon as practical, but not longer than 10 minutes after completion of the catheterisation.

Completed forms were sealed in an envelope and placed in a locked box fastened to the catheter trolley. The study solution enclosed in each study pack was unknown to investigators, including statistician until data was collected and statistical analysis was completed.

Sixty two female ED patients were recruited; thirty one were randomised to receive lignocaine gel and thirty one were randomised to receive plain lubricant gel.

The mean age of recruited patients was 77 years with a range of 31 to 92 years. There were no significant differences between the groups with respect to age, pre-procedural pain, clinical presentation, catheter size or number of attempts.

Values for continuous variables were expressed as means and standard deviations, with statistical significance determined using the t-test. Categorical variables were assessed for significance with chi-squared or Fisher's exact test, if cells with small expected or zero values were present.

The lignocaine gel group had a significant lower mean procedural pain score compared with the plain lubricant gel group (11mm verses 37mm respectively, p=0.003). This translates to a mild compared to moderate pain score respectively. The overall pain scores were significantly lower for the lignocaine gel group as shown by diagram below.

Hence in the Emergency Department setting lignocaine gel is better at reducing the procedural pain of female urethral catheterization. When lignocaine gel is used mild pain scores are reported compared to when plain lubricant gel is used moderate pain scores are reported.

Efforts have started to educate nurses at the study hospital, to standardise on Lignocaine gel. Since the results are transferable to similar Emergency Departments, the study results will be submitted for publication in learned journals. Entry in this ?Baxter Awards? will also raise its profile.

Further observational studies will be considered to ensure mild pain scores are maintained when majority have changed to lignocaine gel.

The A$2 price differential between lignocaine gel and plain lubricating gel is considered a small cost for significant procedural pain reduction. Smaller size syringe from manufacturer may reduce this cost differential.

• Todd KH, Funk KG, Funk JP, Bonacci R. Clinical significance of reported changes in pain severity. Ann Eerg Med. 1996; 27:485-9.
• Tanabe PT, Steinmann R, Anderson J, Johnson D, Metcalf, Ring-Hurn E. Factors affecting pain scores during female urethral catheterization. Acad Emerg Med 11:699-702.

Director, Emergency Department
Sydney South West Area Health Service
Phone: 02 9787 0223