Comparison of the efficacy of two non-pharmacological techniques in reducing pain during urinary catheterization: a randomized clinical trial

Abstract

Background

Urinary catheterization (UC), a commonly performed procedure in emergency departments (EDs), is often associated with significant patient discomfort and pain. This study aimed to compare the effectiveness of two non-pharmacological techniques in reducing pain during UC.

Methods

This randomized clinical trial included 54 male participants aged 18–65 years who underwent UC in the ED of Imam Khomeini Hospital. After obtaining ethical approval and informed consent, eligible patients were randomly assigned to one of three groups: Intervention Group 1 (nasal pressure technique with closed epiglottis exhalation), Intervention Group 2 (deep cough technique), or the control group (routine UC procedure). Pain levels were assessed using the Visual Analog Scale (VAS) at three time points: immediately before, immediately after, and 15 min after the intervention. Data were analyzed using SPSS version 18.

Results

The mean age of participants was 49.09 ± 19.61 years. Both Intervention Group 1 and Intervention Group 2 showed significant differences in pain levels compared to the control group immediately after the intervention (P = 0.046). Specifically, Intervention Group 1 experienced lower pain levels than the control group, while Intervention Group 2 reported higher pain levels. At 15 min post-intervention, pain levels in Intervention Group 1 were lower than in Intervention Group 2, and the control group reported lower pain levels than Intervention Group 2, though this difference was not statistically significant (P = 0.09).

Conclusion

The nasal pressure technique demonstrated a significant reduction in pain during UC, suggesting its potential as a simple, non-pharmacological intervention for pain management. Further studies are recommended to validate these findings and explore their applicability in clinical practice.

Trial registration

This study was retrospectively registered in the Iranian Registry of Clinical Trials (IRCT) under the registration number IRCT20191217045764N3 on March 17, 2021.

Introduction

Urinary catheterization (UC), the insertion of a catheter into the bladder through the urethra, is a widely used procedure in hospitals, long-term care facilities, and emergency settings, with a utilization rate of 15–25% among patients [1, 2]. Despite its clinical necessity, UC is often associated with significant patient discomfort and pain. Factors contributing to this pain include physiological changes, urinary tract rigidity, improper catheter selection, inadequate procedural technique, and the use of unsuitable lubricants [3]. The primary source of pain, however, is trauma and tissue damage caused by friction between the catheter and the highly vascularized, nerve-rich urinary tract [4]. Studies comparing pain levels across various invasive procedures have consistently identified UC as one of the most painful interventions [5], with reported pain levels ranging from mild to moderate (8.7 mm to 58 mm on pain scales) depending on catheter size and technique [6].

While lubricants and anesthetic gels, such as lidocaine, are commonly employed to mitigate pain, their efficacy remains limited. Studies report residual pain levels ranging from 3.8 mm to 38 mm even with the use of lidocaine gel [7]. This underscores the need for alternative strategies to address pain during UC. Nurses, as frontline caregivers, play a critical role in managing patient discomfort and should be equipped with evidence-based pharmacological and non-pharmacological methods to minimize pain during invasive procedures [8, 9].

In recent years, non-pharmacological approaches have gained attention for their potential to reduce pain without the side effects associated with medications. Techniques such as distraction, relaxation, skin stimulation, hypnosis, cold application, and the Valsalva maneuver have been explored [10]. The Valsalva maneuver, in particular, has shown promise in pain management. By increasing intrathoracic pressure through forced exhalation against a closed airway, the maneuver stimulates the vagus nerve, leading to an analgesic effect mediated by the inhibition of noradrenergic, serotonergic, and endogenous opioid systems [11]. For example, Hosseini et al. (2024) demonstrated that the Valsalva maneuver significantly reduced pain during venous catheter insertion [12]. Similarly, Yilmaz et al. (2024) found that a modified cough technique, which mimics the Valsalva maneuver, effectively reduced pain during peripheral catheter placement [13].

Another non-pharmacological method involves applying pressure to the tip of the nose, a technique that combines the Valsalva maneuver with cognitive distraction. Maqsoodi et al. (2016) reported that this method significantly reduced venous pain in children by diverting attention and activating pain-inhibitory pathways [14]. Additionally, Stav et al. (2017) found that adopting a defecation posture during UC facilitated catheter insertion and reduced pain through the Valsalva mechanism, though this approach may pose practical challenges in clinical settings [15].

Given the cultural acceptability, simplicity, and cost-effectiveness of techniques such as nasal pressure and controlled coughing, these methods hold promise for pain management during UC. Both approaches leverage the dual mechanisms of the Valsalva maneuver and cognitive distraction, which collectively alter pain perception and provide relief [16]. This study aims to compare the efficacy of these two non-pharmacological techniques—nasal pressure and deep coughing—in reducing pain during UC, with the goal of identifying a practical, non-invasive strategy to enhance patient comfort.

Based on the literature and theoretical mechanisms of pain modulation through the Valsalva maneuver and distraction techniques, this study proposed the following hypotheses:

• H1: The nasal pressure technique significantly reduces pain during urinary catheterization compared to the control group.

• H2: The deep cough technique significantly reduces pain during urinary catheterization compared to the control group.

• H3: The nasal pressure technique is more effective than the deep cough technique in reducing pain during urinary catheterization.

Methods

Study design

This study was a two-group randomized clinical trial with a control group, conducted from August 2020 to July 2022 at Imam Khomeini Hospital in Esfarayen, North Khorasan, Iran. The study aimed to compare the effectiveness of two non-pharmacological techniques—nasal pressure with compressive exhalation (closed glottis) and deep coughing—against a control group (routine method) in reducing pain during urinary catheterization (UC). The study population consisted of male patients aged 18–65 years who required UC for diagnostic or therapeutic purposes (Fig. 1).

Fig. 1.

CONSORT Flow Chart of participant

Participants

Participants were selected based on predefined inclusion and exclusion criteria. Inclusion criteria included:

• Male gender,

• Age between 18 and 65 years,

• Ability to cooperate for pain assessment (no mental disorders),

• Requirement for UC for any clinical reason,

• No recent use of narcotic or non-narcotic painkillers.

Exclusion criteria included:

• History of heart disease,

• Active urinary tract infection,

• Pre-existing pain conditions (e.g., chronic pelvic pain syndromes, interstitial cystitis),

• Previous urinary catheterization,

• Urinary tract stricture,

• Neurological conditions impairing pain perception (e.g., neuropathies, reduced consciousness),

• Anesthetized or intubated patients,

• Mental health conditions hindering effective communication,

• Presence of hematuria.

Pain assessment

Pain intensity was measured using the Visual Analog Scale (VAS), a validated and widely used tool for pain assessment. The VAS consists of a 100-mm horizontal line, with the left endpoint labeled “no pain” (0 mm) and the right endpoint labeled “most severe pain” (100 mm). Participants were instructed to mark a single point on the line corresponding to their perceived pain level. The VAS scores were categorized as follows:

• 0: No pain,

• 1–39 mm: Mild pain,

• 40–69 mm: Moderate pain,

• 70–100 mm: Severe pain.

The VAS has been extensively validated in prior studies, demonstrating its reliability, ease of use, and independence from demographic variables [12, 17–19]. In this study, pain levels were assessed at four distinct time points:

1. Before the injection of lidocaine gel,

2. Immediately before catheterization,

3. Immediately after catheterization,

4. Fifteen minutes after the completion of the procedure.

Sample size and randomization

The sample size was calculated based on a review of the literature and similar studies, using the following parameters: p1 = 0.20, p2 = 0.55, α = 0.05, and β = 0.2. This calculation determined that a minimum of 30 participants per group was required to achieve adequate statistical power (10). However, due to the COVID-19 pandemic, the final sample sizes were adjusted to 29, 29, and 27 participants in Intervention Group 1, Intervention Group 2, and the control group, respectively, resulting in a total of 87 participants.

Randomization was conducted using a box containing cards labeled with the assigned intervention (nasal pressure technique, deep cough technique, or routine method). The cards were prepared using a random number sequence generated by SPSS version 18 to ensure unbiased allocation. Randomization was performed prior to any baseline pain assessment or intervention to avoid allocation bias. Although random, group comparability was verified, and demographic variables such as age, education level, occupation, medication use, and inpatient department were well-balanced across the three groups.

Data collection

In this study, data collection and intervention implementation were carried out in a structured and standardized manner. A researcher-developed form was used to gather demographic and clinical data, including age, education level, occupation, marital status, medication use, hospital ward, blood pressure, heart rate, respiratory rate, and body mass index (BMI). Pain intensity was assessed using the Visual Analog Scale (VAS). All data were collected by trained research nurses who were blinded to group assignments, and all forms were reviewed for completeness by the principal investigator.

Baseline pain was assessed prior to any intervention and before the administration of lidocaine gel. This pain reflected any pre-existing discomfort in the genitourinary area, which could have been related to underlying conditions such as urinary retention, infection, or anxiety about the procedure.

After obtaining informed consent, participants were randomly assigned to one of three groups using sealed envelopes containing cards labeled with group assignments. These assignments were generated using a random number sequence in SPSS version 18 to ensure unbiased allocation. Group comparability was verified in terms of demographic and clinical characteristics.

Prior to urinary catheterization (UC), all patients received 5 mL of lidocaine gel intraurethrally, followed by a 3-minute clamping of the penis. UC was then performed using an 18 F Tiemann urethral catheter. In the Intervention 1 Group (Nasal Pressure with Compressive Exhalation), a trained nurse explained and demonstrated the technique to the patient. The patient was instructed to press the tip of their nose while simultaneously performing a forceful exhalation with a closed glottis (similar to a Valsalva maneuver). The catheter was inserted during this maneuver.

In the Intervention 2 Group (Deep Coughing Technique), patients were taught to take a deep breath, hold it, and then perform a strong cough using abdominal muscle contraction. The procedure was explained and demonstrated by the same nurse. The urinary catheter was inserted during the second forceful cough, approximately 10 s after the initial instruction.

In the Control Group, UC was performed using the standard method without any additional breathing or pressure techniques.

Each intervention was performed only once, synchronized with catheter insertion. The interventions lasted approximately 10–15 s. All catheterizations and interventions were performed by the same experienced nurse to ensure consistency, while pain assessments were conducted independently by blinded assessors. The steps for both interventions were based on previous research on non-pharmacological techniques for procedural pain management; however, specific studies validating these exact maneuvers in the context of urinary catheterization were limited, which we have noted in the limitations section.

Statistical methods

Data analysis was conducted using SPSS software (version 18). The normality of data distribution was assessed using the Kolmogorov-Smirnov test. Due to the non-normal distribution of some variables, non-parametric tests were employed for analysis. Descriptive statistics, including mean ± standard deviation, were used to summarize continuous variables, while frequencies and percentages were used for categorical data.

For inferential analysis:

• One-way ANOVA was applied to compare quantitative continuous variables with normal distribution across groups.

• Chi-square test was used to analyze categorical variables.

• Wilcoxon test was utilized for continuous variables with non-normal distribution.

Post-hoc comparisons between groups were performed using Tukey’s test to identify specific differences. Additionally, univariate logistic regression was conducted to examine correlations between pain scores (associated with catheterization techniques) and variables such as BMI and vital signs post-intervention.

Results

A total of 93 male patients were initially enrolled; 87 participants met the eligibility criteria and were included in the final analysis. The mean age of the participants was 49.09 ± 19.61 years. Demographic characteristics were evenly distributed across the three groups, with no statistically significant differences observed (P > 0.05). In terms of occupation, 24.1% of participants in Intervention Group 1, 48.3% in Intervention Group 2, and 7.4% in the control group were workers. The proportion of self-employed individuals was similar in Intervention Groups 1 and 2 (27.6%) and slightly higher in the control group (33.3%). Employees accounted for 20.7%, 20.7%, and 7.4% of participants in Intervention Groups 1, 2, and control, respectively. Regarding educational level, the proportion of illiterate participants was highest in the control group (55.6%) compared to Intervention Group 1 (13.8%) and Intervention Group 2 (20.7%). Participants with elementary education represented 31.0% in both Intervention Groups 1 and 2 and 18.5% in the control group. Those with high school diplomas were most common in Intervention Group 1 (34.5%) and least common in the control group (11.1%). College-educated individuals accounted for 20.7% in both Intervention Groups and 14.8% in the control group (Table 1).

Table 1.

Comparison of Demographic and Clinical Characteristics Across Study Groups

Characteristics	Intervention 1 (n = 29)	Intervention 2 (n = 29)	Control (n = 27)	P-value
Age Mean ± SD	47.09 ± 18.92	46.06 ± 23.39	54.23 ± 16.78	0.42
Occupation n (%)
Worker	7 (24.1)	14 (48.3)	2 (7.4)	0.95
self-employment	8 (27.6)	8 (27.6)	9 (33.3)
Employee	6 (20.7)	6 (20.7)	2 (7.4)
Other	8 (27.6)	1 (3.4)	14 (51.9)
Level of Education n (%)
illiterate	4 (13.8)	6 (20.7)	15 (55.6)	0.80
elementary	9 (31.0)	9 (31.0)	5 (18.5)
High school and diploma	10 (34.5)	8 (27.6)	3 (11.1)
College education	6 (20.7)	6 (20.7)	4 (14.8)
BP before intervention (mmHg) Mean ± SD	114.17 ± 27.6	118.82 ± 20.44	121.07 ± 26.56	0.64
Heart rate before intervention (bpm) Mean ± SD	86.50 ± 13.74	80.28 ± 14.43	86.46 ± 14.24	0.39
Respiratory rate before intervention (per min) Mean ± SD	17.48 ± 1.22	17.85 ± 2.22	17.64 ± 2.46	0.66

Pain intensity analysis

No significant differences in pain intensity were observed between Intervention Group 1, Intervention Group 2, and the control group before lidocaine gel injection or immediately before catheter insertion (Table 2). However, immediately after the intervention, both Intervention Group 1 and Intervention Group 2 showed significant differences in pain intensity compared to the control group (P = 0.046). Specifically:

Table 2.

Comparison of Pain Scores Across Intervention Groups 1 and 2 and the Control Group

Outcome	Intervention 1 (n = 29)	Intervention 2 (n = 29)	Control (n = 27)	F-value	P-value
Pain before injecting lidocaine gel	2.4 ± 2.8	4.4 ± 3.3	3.3 ± 3.2	1.71	0.19
Pain before urinary catheterization	2.0 ± 2.6	3.9 ± 3.2	3.0 ± 3.1	1.69	0.20
Pain immediately after catheterization	3.25 ± 1.94	5.26 ± 2.40	4.44 ± 2.69	3.29	0.046
Pain 15 min after catheterization	1.50 ± 2.03	3.00 ± 2.50	2.88 ± 2.26	2.51	0.09

• Intervention Group 1 (nasal pressure technique) reported lower average pain levels than the control group.

• Intervention Group 2 (deep cough technique) reported higher average pain levels than the control group.

At 15 min post-intervention, the average pain score in Intervention Group 1 (2.03 ± 1.50) was lower than in Intervention Group 2, and the control group reported lower pain levels than Intervention Group 2. However, these differences were not statistically significant (P = 0.09) (Table 2).

Secondary outcomes

No significant associations were found between pain intensity and physiological variables such as blood pressure, heart rate, respiratory rate, or BMI at any stage of pain measurement (Table 3). To account for potential confounding factors, multiple linear regression analysis was performed using the Visual Analog Scale (VAS) score as the dependent variable. Independent variables, including age, medication use, education level, and occupation, showed no significant relationship with pain intensity (P ≤ 0.005).

Table 3.

Relationship Between Vital Signs and Reported Pain Across Study Groups

Vital Sign	Kruskal-Wallis Test	P-value
Blood Pressure (BP)
Before urinary catheterization	87/0	0.64
Immediately after catheterization	14/1	0.56
15 min after catheterization	65/0	0.72
Heart Rate (HR)
Before urinary catheterization	84/1	0.39
Immediately after catheterization	40/2	0.30
15 min after catheterization	43/2	0.32
Respiratory Rate (RR)
Before urinary catheterization	23/1	0.54
Immediately after catheterization	62/0	0.73
15 min after catheterization	47/0	0.79

Discussion

The findings of this study demonstrate that the nasal pressure technique, involving holding the tip of the nose and exhaling with a closed glottis, significantly reduced pain immediately after UC compared to the control group. Although the reduction in pain at 15 min post-intervention was not statistically significant, the trend suggests a potential benefit that may reach significance with a larger sample size in future studies. These results align with the findings of Stav et al. (2017), who reported that the Simultaneous Voiding Maneuver, a form of the Valsalva maneuver, effectively reduced pain during UC in men [15]. The nasal pressure technique likely achieves its analgesic effect through vagus nerve stimulation, a mechanism shared with the Valsalva maneuver.

In contrast, the deep cough technique did not demonstrate a significant reduction in pain and, in some cases, was associated with higher pain levels compared to the control group. This suggests that the deep cough technique may not effectively stimulate the Valsalva maneuver or provide sufficient pain relief. While Willete et al. (2012) recommended the cough technique for pain management [17], its efficacy remains unconfirmed in clinical trials. Further research with larger sample sizes is needed to evaluate its potential benefits.

The nasal pressure technique offers several advantages over other methods. Unlike the Simultaneous Voiding Maneuver, which may inadvertently trigger urination and complicate the procedure, the nasal pressure technique is less likely to interfere with UC. This makes it a more practical option for clinical use, particularly in patients with urinary incontinence.

Comparisons with other studies highlight the unique contributions of this research. For example, Zhao et al. (2015) found that liquid paraffin was more effective than 2% lidocaine gel in reducing UC-related pain [19]. However, their study focused on pharmacological interventions, whereas the present study evaluated non-pharmacological techniques. Similarly, O’Hearn and Wright (2011) explored the use of coccygeal epidural anesthesia in male cats, an invasive method with potential side effects [20]. In contrast, the nasal pressure technique is non-invasive, cost-effective, and easy to administer, making it a safer alternative for pain management.

The study by Paul et al. (2013) introduced a visually guided catheterization method using a fiber-optic camera, which improved procedural success and reduced trauma [21]. While effective, this approach requires specialized equipment and may not be feasible in all clinical settings. The nasal pressure technique, on the other hand, is simple, inexpensive, and accessible, offering a practical solution for pain reduction during UC.

Limitations

This study has several limitations. The sample size was reduced due to the COVID-19 pandemic, which limited the number of eligible participants. Additionally, the study was conducted at a single center, which may affect the generalizability of the findings. Furthermore, although the non-pharmacological techniques used (nasal pressure with compressive exhalation and deep coughing) were adapted based on principles of pain modulation and have been explored in other clinical contexts, there is a lack of validated protocols or prior studies specifically supporting their use during urinary catheterization. Also, although there were no statistically significant differences in baseline pain between groups, a clinically meaningful variation—especially higher baseline pain in the deep cough group—may have influenced post-intervention outcomes. Therefore, the effectiveness and reproducibility of these techniques should be interpreted with caution. Future studies with larger, multi-center cohorts and standardized intervention protocols are recommended to validate these results and explore their applicability in diverse clinical settings.

Conclusion

The nasal pressure technique significantly reduced pain during, immediately after, and 15 min following UC in male patients compared to the control group. These findings suggest that this simple, non-pharmacological method can be an effective tool for pain management during UC. If confirmed by further research, this technique could be integrated into clinical practice to improve patient comfort and outcomes.

Abbreviations

UC

Urinary catheterization

Eds

emergency departments

VAS

Visual Analog Scale

BMI

body mass index

Authors’ contributions

All authors have read and approved the manuscript. Study design: JS, AA; data collection and analysis: HA, MMG, MGM; manuscript preparation: MN, AA, AM, MG.

Funding

The present study was carried out under the financial support of Esfrayen Faculty of Medical Sciences.

Data availability

The datasets generated in the present study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved at Ethics Committee of Esfrayen Faculty of Medical Sciences (IR.EFRUMS.REC.1399.012) and registered in Iranian trial registration center. Written informed consent was obtained from all participants and also from their companions in case of severity of patient’s status. During examination and history taking, the research goals were explained to patients and their family in the shortest possible time, and the patient was enrolled in case of satisfaction. Clinical trials registration number is IRCT20191217045764N3.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.