Since its accidental discovery by Crystle in 1971, evaluation of urethral hypermobility with the Q-tip (Unilever PLC, London, United Kingdom) test by placing a cotton swab in the urethra has been very useful in the differential diagnosis and management of urinary incontinence.1 Measurement of postvoid residual urine volume (PVR) is also a critical part of evaluation of lower urinary tract dysfunction. According to the most recent clinical practice guidelines prepared by the Agency for Health Care Policy and Research, PVR assessment is recommended in the basic evaluation of all patients with urinary incontinence.2 Combination of these tests has been incorporated in many clinical practice settings where women with urinary incontinence and pelvic floor disorders are evaluated.
The use of water-soluble lubricants has been the standard for female urethral catheterization to prevent physical trauma and patient discomfort.3 However, there is no consensus among popular gynecology textbooks about the type of lubricant to be used for the Q-tip test because of lack of evidence. They all recommend lubrication but suggest a variety of agents, including saline and lidocaine jelly, to reduce pain during urethral insertion.4–6 Lidocaine jelly is not readily available and may be costly in many clinical settings, whereas water-based lubricants are ubiquitous in any urologic or gynecologic practice. The objective of this study is to compare the pain perception between 2% lidocaine jelly and a plain aqueous gel when they are used for urethral straight catheterization and the Q-tip test.
MATERIALS AND METHODS
This study was approved by the institutional review board at Baystate Medical Center. The study pool consisted of all women who presented to a single urogynecologist’s office for an initial consultation with a complaint of urinary incontinence and/or pelvic organ prolapse between November 2007 and September 2008. The exclusion criteria were composed of being a minor, pregnancy, allergy to lidocaine or plain aqueous gel, any current use of analgesia, structural abnormalities of the urethra, active genital Herpes or other vulvovaginal infections, or inability to cooperate with pain assessment due to mental disorders. Those patients who consented for the research were then randomly assigned either to 2% lidocaine hydrochloride jelly (Lidocaine Hydrochloride Jelly, Akorn, Buffalo Grove, IL) or aqueous gel (Surgilube, Fougera, Melville, NY) using computer-generated blocks of 10. The latter is a commonly used, commercially available plain aqueous gel. Both the urogynecologist who performed the examinations and the patient were blinded to the randomization. The appearances of the study gels were indistinguishable. Based on our power analysis targeting a power of 0.80, an α value of 0.05, and 20% difference in the median pain perception between the groups, we aimed to recruit a sample of, at a minimum, 132 subjects.
First, demographic information, including the age, parity, previous vaginal births, body mass index, race, diabetes, vaginal atrophy, neurologic impairment, current estrogen use, indication for visit, and examination anxiety, was collected. Immediately after voiding, each patient was placed in a lithotomy position. An independent nurse who was not involved in the patient’s care prepared the study gels according to the randomization behind a curtain. After cleansing external urethral meatus with povidone iodine solution, a lubricated a sterile 14-F polyvinyl chloride Mentor Self-Cath catheter (Coloplast, Minneapolis, MN) was placed transurethrally into the bladder to measure the PVR. Following removal of the catheter, a cotton swab, lubricated with the same allocated gel, was advanced to the urethrovesical junction until resistance was felt. The angle of the swab with the horizontal plane was measured at rest and with a Valsalva maneuver. All the examinations were performed by the same urogynecologist in the same order. Immediately following the Q-tip test, the patient’s perception of pain level was measured using a validated pain scoring system, the Wong-Baker FACES Pain Rating Scale, a visual scale where 0 represents no pain and 5 represents worst imaginable pain.7 The rest of the physical examination was completed after this pain assessment.
We evaluated patient characteristics and pain score variables by exposure to either lidocaine or aqueous gel using SPSS 11.01 software (SPSS Inc., Chicago, IL). For continuous variables, we calculated the median and range and then evaluated significant differences using the Mann Whitney U test because they did not fulfill the criteria for parametric tests. For categorical variables, we calculated the number and percent and then evaluated significant differences using Pearson’s χ2 test. Significance for all results was set at P<.05.
Every eligible new patient accepted participation in the study. Of 137 women who were enrolled in this study, 69 were assigned to the lidocaine arm and 68 to the aqueous gel arm. The mean age±standard deviation of patients was 58.5±12.7. Approximately 90% of all women in the study were white. All the baseline characteristics of the patients were similar between the groups (Table 1).
Significantly fewer women in the lidocaine group (62.3%) reported any pain, a score of 1–5, than those in the aqueous gel group (80.9%), with an odds ratio of 0.39 and 95% confidence interval of 0.18–0.85 (P=.016). In other words, patients receiving lidocaine were approximately 60% less likely to experience any pain as compared with those allocated to aqueous gel. Although there was a significant difference in median pain scores between the lidocaine jelly (median score=1, range 0–5) and aqueous gel groups (median score 2, range 0–4) (P<.001), the median pain scores remained at below 2 in both groups, which is considered within tolerable range. When we compared the patients who graded their pain within the 3–5 range, which can be considered significant pain, we noted that significantly more women (17.6%) who were allocated to aqueous gel fell into this category than those assigned to lidocaine jelly (5.7%) (P=.001).
Our study indicates that applying 2% lidocaine jelly onto the catheter and then the cotton swab during evaluation of PVR and the Q-tip test reduces the discomfort associated with these procedures when compared with an aqueous gel. We were not able to differentiate the pain perception between the measurement of PVR and the Q-tip test because of our study design.
The workup for urinary incontinence and pelvic floor disorders is incomplete without assessment of urethral mobility and PVR.2 There is no doubt that urethral lumen is very sensitive to passage of any instrument. Recently, we studied whether we could reduce the number of urethral manipulations by performing the Q-tip test with a catheter.8 Systematic review by the British Department of Health concluded that lubrication was necessary for female urethral catheterization.9 Although most experts emphasize local anesthetic use during the Q-tip test, our extensive search of literature indicated that this recommendation was not evidence based.4,5 It takes approximately 40 seconds to 4 minutes until the anesthetic effect of short-acting local anesthetics occurs.10 That is why it is a common practice to use an intraurethral anesthetic gel a few minutes before transurethral procedures such as cystoscopy. In fact, we owe the Q-tip test to a serendipitous discovery that occurred when lidocaine jelly was inserted with a cotton swab to the bladder neck to reduce the discomfort associated with chain cystourethrogram.1 During the Q-tip test, it does not seem reasonable to assume that lidocaine on the cotton swab will become effective on contact. It is plausible that the lubrication provided by the aqueous gel vehicle, not the anesthetic effect of lidocaine, is the actual factor that reduces pain. Hence, we decided to undertake this double-blinded study.
We will review the findings of some important studies evaluating the use of anesthetic agents for female urethral catheterization, because we were not able to find any report for Q-tip test. In a randomized trial, lignocaine gel substantially reduced the procedural pain of female urethral catheterization when compared with an aqueous lubricating gel.11 However, Tanabe et al12 claimed that female urethral catheterization is not very painful, and they did not support the use of lidocaine gel. Garbutt et al13 evaluated the discomfort of urethral catheterization performed immediately or after a 2 minutes delay after instillation of local anesthetic gel. They found that after the instillation of local anesthetic gel, passage of the catheter immediately or after a 2-minute delay makes no difference to the pain experienced during the procedure. On the other hand, Van der Burght et al14 showed that 1–4 minutes after instillation of lignocaine, pain during catheterization is decreased. The limitation of the study was the relatively short duration between lidocaine application and catheter insertion.
We are not certain if our results may be applied to other commercially available aqueous lubricants. We did not obtain independent scores after each one of the PVR and Q-tip components to reduce the inconvenience of this research for the patient and mimic our routine. In addition, one can never eliminate the effects of the first component on the second one. There is a possibility that lidocaine inserted into the urethra with the catheter reduced the pain during subsequent cotton-tipped swab insertion, seemingly the more uncomfortable component of our combined examination. One may suggest that we should have used a control arm with no agent; however, we did not think that it would be ethical because of the considerable evidence in favor of using lubrication for female urethral catheterization.
Based on our results, we recommend the use of 2% lidocaine jelly instead of aqueous gel when female urethral straight catheterization and the Q-tip test are done together in this specific order. We also stress that even the plain aqueous agents are quite effective, because significant pain (a score of 3–5 out of 5) was noted in only 17.6% of the patients in that group. The practice of lubrication with an aqueous lubricant may still be appropriate when the cost or availability of lidocaine jelly is an issue.
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