# Hypnosis for unplanned procedural pain in the intensive care unit: the HYPIC randomized clinical trial

Adel Maamar, Claude Faleur, Kristell Pedrono, Marie-Pierre Adeux, Magali Anne, Adeline Verdes, Pierre Fillâtre, Matthieu Debarre, Nathalie Mercier, Matthieu Revest, et al.

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## To cite this version:

Adel Maamar, Claude Faleur, Kristell Pedrono, Marie-Pierre Adeux, Magali Anne, et al.. Hypnosis for unplanned procedural pain in the intensive care unit: the HYPIC randomized clinical trial. Critical Care, 2025, 29 (1), pp.312. 10.1186/s13054-025-05563-9. hal-05242273

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# Hypnosis for unplanned procedural pain in the intensive care unit: the HYPIC randomized clinical trial

Adel Maamar¹*†, Claude Faleur¹†, Kristell Pedrono², Marie-Pierre Adeux¹, Magali Anne¹, Adeline Verdes², Pierre Fillâtre², Matthieu Debarre², Nathalie Mercier², Matthieu Revest⁴, Nicolas Massart², Noémie Poilvet², Nicolas Terzi¹, Jean-Marc Tadié¹,³, Arnaud Gacouin¹,³ and Bruno Laviolle³

**Abstract**

**Background** Pain and anxiety are frequent among critically ill patients undergoing unplanned invasive procedures, and pharmacological pain relief is not always possible. Although hypnosis is widely used in planned painful procedures, studies are lacking in this specific setting. Thus, we aimed to assess whether hypnosis plus standard care reduced pain and anxiety in critically ill patients undergoing an unplanned invasive procedure in comparison to standard care.

**Methods** The HYPIC trial was a randomized, single-blind, multicenter clinical trial of hypnosis during unplanned invasive procedures versus standard care for critically ill patients conducted in two French intensive care units (ICUs) from December 27, 2019, to January 25, 2022. Patients were randomly assigned to receive hypnosis plus standard care by trained healthcare providers or standard care. The hypnotherapists were in the room for both arms to maintain blindness. The primary endpoint was the difference in pain level experienced during the invasive procedure assessed immediately after the end of the procedure between the two groups. The secondary outcomes were anxiety level, lidocaine consumption and stress experienced by the ICU nurses in charge of the patients.

**Results** We included 78 patients. The pain level, assessed with a numeric pain scale (range, 0–10), was not significantly different between the two groups (2.2 ± 2.9 vs. 2.2 ± 3, difference 0 pts [95% CI -1.3; 1.3], *p* = 0.89). The level of anxiety was significantly lower in the hypnosis group (2.4 ± 2.8 vs. 4.1 ± 3, difference − 1.7 [-3; -0.4], *p* = 0.01), as was the level of stress experienced by the ICU nurses (0.1 ± 0.4 vs. 0.9 ± 1.5, difference − 0.8 [-1.3;-0.3], *p* = 0.003), and the patients were three times less likely to require increased lidocaine consumption (odds ratio: 0.3 [0.13–0.84], *p* = 0.02) in the hypnosis group.

**Conclusion** While hypnosis did not result in a statistically significant reduction in unplanned procedural pain, it seems to reduce anxiety, increase comfort, and reduce the stress level of healthcare providers.

Full list of author information is available at the end of the article

<footnote>†Adel Maamar and Claude Faleur have contributed equally to this work.</footnote>

<footnote>*Correspondence:
Adel Maamar
adel.maamar@chu-rennes.fr</footnote>
**Trial registration:** The study was registered on ClinicalTrials.gov (NCT04129333) on 14 October 2019, before the first patient was enrolled.

**Keywords** Hypnosis, Intensive care unit, Catheter placement, Chest tube, Randomized controlled trial, Critical illness

## Introduction

A significant proportion of patients admitted to the intensive care unit (ICU) need an invasive procedure during their ICU stay [1]. The pain experienced during this invasive procedure depends on the procedure itself and the equipment used, as well as the patient's level of anxiety and stress [2, 3]. In addition, the unplanned nature of invasive procedures in the ICU setting increases anxiety, stress, and discomfort, thus increasing the need for efficient techniques to control pain and anxiety in these patients. However, reducing procedural pain presents several difficulties. First, pain relief and sedation may be limited because of critical illness or because of comorbidities. Second, the use of analgesics and sedatives is associated with adverse side effects [4], which could impair the outcomes of critically ill patients. These adverse effects are numerous and common, such as hypotension, respiratory depression, delirium, withdrawal syndromes, increased length of stay, increased paramedical workload, and, more generally, increased hospital costs. While hypnosis is not expected to prevent all adverse effects—such as delirium—its use may help reduce the required doses of opioids or sedatives during procedures, potentially mitigating dose-dependent side effects such as hypotension and respiratory depression.

In this context, hypnosis could be a nonpharmacological complementary technique to control pain and anxiety in patients who cannot benefit from drug treatment or in addition to drug treatment, which is widely used in planned procedures, especially in the surgical setting [5-7]. It is an easy-to-use technique with low cost and minimal side effects [6, 8], and has been used for more than 50 years in both adult and pediatric patients. Its indications continue to expand and now include various settings such as major surgeries, radiologic interventional procedures or cardiologic invasive procedures. A recent study revealed that hypnosis during atrial flutter ablation is superior to placebo for alleviating pain and reducing morphine consumption [9]. Although the ICU remains a challenging environment for hypnosis, interest in its use is increasing. A recent trial explored hypnosis in ICU patients but patients were undergoing scheduled cardiac surgery [10], and no randomized controlled trials have yet been published to evaluate its feasibility and efficacy in unplanned procedures in the ICU.

To the best of our knowledge, although there are many studies on planned procedures [5-7], no studies have been conducted to evaluate the effects of hypnosis

on patients admitted to the ICU or its feasibility during unplanned invasive procedures.

We aimed to assess, in this context, whether hypnosis reduces pain and anxiety in critically ill patients undergoing an unplanned invasive procedure in comparison with the standard of care.

## Methods

### Study design

The HYPIC trial was a prospective, multicenter, randomized, controlled, single-blind, superiority trial conducted in two ICUs in France. The study was registered at ClinicalTrials.gov (NCT04129333) before the first patient was enrolled. The trial was approved for all centers by a central Ethics Committee (IDCRB 2019-A01775-52, Comité de Protection des Personnes Bron —Région SUD-EST II, France) according to French law on October 9, 2019. This study was conducted in accordance with the ethical standards of the Declaration of Helsinki [11] and the Good Clinical Practice requirements [12]. Written informed consent was required for all patients prior to enrollment and randomization. The trial was conducted and reported in accordance with the CONSORT Statement 2010 and the extension of the CONSORT Statement for the evaluation of nonpharmacological treatments. The complete trial protocol is available in the Supplement.

### Study population

ICU patients aged over 18 years were eligible if they underwent an invasive procedure (central venous or arterial catheter placement, dialysis catheter or chest tube) during their ICU stay and had a Glasgow coma scale of 15 at the time of the invasive procedure. The exclusion criteria were as follows: (i) procedure immediately needed; (ii) decompensated psychiatric disorder; (iii) treatment with continuous intravenous analgesics or sedative drugs; (iv) cognitive impairment or delirium according to the CAM-ICU; (v) intubated patients; (vi) adults subject to legal protection; and (vii) patients who were already participating in an interventional study on analgesics or sedative drugs.

### Randomization and blinding

The inclusion and randomization of participants were performed by site investigators via a web-based platform. Patients were randomized at a 1:1 ratio to either hypnosis plus standard care (hypnosis group) or standard care (control group). The allocation sequence was
computer-generated by the study's statistician, with stratification based on the participating center.

Blinding of healthcare providers and participants was not feasible due to the nature of the interventions. However, to reduce assessment bias, the study employed a single-blind design: outcome assessors were unaware of the randomization arm and were not present during the intervention. To support this blinding, the trained hypnosis nurse was present in the room for both groups. In the hypnosis group, the nurse conducted the intervention; in the control group, the nurse remained present but passive.

## Study interventions

The hypnosis session was conducted by dedicated and trained ICU nurses, who were not directly involved in the clinical management of the patients. The hypnosis session consisted of short individual sessions that were personalized to each patient, using sensorial language and paraverbal and rewording techniques to promote patient comfort/well-being according to the patient's choice of a safe place or leisure activity (Supplementary appendix). During the session, only the trained and dedicated nurse talked to the patient. The invasive procedure could start only after the agreement of the hypnotherapist.

In the control group, the patients were managed with no specific recommendation on wording or nonverbal communication.

## Analgesia management

In both groups, there was no specific recommendation regarding analgesia or sedation management, and patients were managed in accordance with each center's standard care protocol. No premedication was given. Local anesthesia and analgesia management were left at the discretion of the physician in charge of the patient.

## Outcomes

The primary endpoint was the pain level experienced during the invasive procedure assessed immediately after the end of the procedure between the two groups. A 10-point numeric scale was used, with 0 indicating no pain and 10 indicating intolerable pain.

The secondary outcomes were as follows: the level of anxiety and comfort experienced during the procedure was also measured using a 10-point numeric scale (from 0 indicating no anxiety or discomfort to 10 indicating intolerable anxiety or discomfort); the level of pain experienced in the hour following the invasive procedure; the type and dose of analgesic and sedative drugs taken during the first hour after the invasive procedure; the dose of lidocaine consumption during the invasive procedure; the duration of the procedure; and the number of attempts. Complications during the procedure, the level

of stress experienced by the nurse in charge of the patient using a 10-point numeric scale (0 indicating no stress and 10 indicating intolerable stress), and the length of stay in the ICU during the first 28 days were also assessed.

Outcomes were recorded by an independent clinical research associate blinded to the study arm.

## Sample size

On the basis of previous studies in patients who underwent central venous catheter placement, we estimated a mean pain level of 6.8 (±2) in the standard group [3, 13, 14]. The number of participants included was calculated considering a clinically relevant difference of 1.5 points on the pain numeric scale, with a standard deviation (SD) of 2. With 90% power (β = 0.10) and a 5% type I error (two-sided tests), the required sample size was 76 patients. Therefore, we planned to include 80 patients (40 per arm).

## Statistical analysis

Categorical variables are presented as counts and percentages. Continuous variables are presented as the means and standard deviations or medians and interquartile ranges when the assumption of normality was not met using the Kolmogorov-Smirnov test. All analyses were performed on an intent-to-treat basis according to the statistical analysis plan. No imputation method was used in the case of missing data, and for both quantitative and qualitative variables, missing data were reported.

To compare the distributions of continuous variables, t test or Mann-Whitney test was used. Categorical variables were compared using χ2 test or Fisher's exact test when necessary. Linear regression was used to estimate the mean differences between the two groups and between baseline and the end of the procedure (H0).

All tests were 2-sided, and *p* < 0.05 was considered statistically significant. Statistical analyses were performed using a software program (SAS® 9.4, SAS Institute, Cary, NC, USA) and R 4.4.1 (R Foundation for Statistical Computing, Vienna, Austria).

## Results

### Patients

Between December 27, 2019, and January 25, 2022, a total of 78 patients were randomized, and 39 and 39 patients were allocated to the control and hypnosis groups, respectively (Fig. 4). Patient characteristics were well balanced between the two groups (Table 1). Briefly, the mean patient age was 59.8 (14.4) years, and 38 (49%) patients were women.

### Procedures

The types of invasive procedures were well balanced between the two groups (Supplementary Table 1). Venous
<table><caption>**Table 1** Baseline patient characteristics</caption><thead><tr><th rowspan="2"></th><th rowspan="2">Total (n = 78)</th><th colspan="2">Group</th></tr><tr><th>Hypnosis (n = 39)</th><th>Control (n = 39)</th></tr></thead><tbody><tr><td><strong>Demographic features</strong></td><td></td><td></td><td></td></tr><tr><td>Male, n</td><td>40 (51.3)</td><td>21 (53.8)</td><td>19 (48.7)</td></tr><tr><td>Age, y</td><td>59.8 (14.0)</td><td>60.6 (14.8)</td><td>59.0 (13.3)</td></tr><tr><td>BMI, m.kg<sup>-2</sup></td><td>28.0 (6.8)</td><td>27.1 (6.1)</td><td>29.0 (7.3)</td></tr><tr><td><strong>Medical history</strong></td><td></td><td></td><td></td></tr><tr><td>Chronic heart disease, n</td><td>38 (48.7)</td><td>18 (46.2)</td><td>20 (51.3)</td></tr><tr><td>Chronic lung disease, n</td><td>21 (26.9)</td><td>13 (33.3)</td><td>8 (20.5)</td></tr><tr><td>Liver cirrhosis, n</td><td>17 (21.8)</td><td>11 (28.2)</td><td>6 (15.4)</td></tr><tr><td>Neurological history, n</td><td>14 (17.9)</td><td>7 (17.9)</td><td>7 (17.9)</td></tr><tr><td><strong>Admission reason</strong></td><td></td><td></td><td></td></tr><tr><td>Respiratory failure, n</td><td>27 (34.6)</td><td>14 (35.9)</td><td>13 (33.3)</td></tr><tr><td>Circulatory failure, n</td><td>16 (20.5)</td><td>8 (20.5)</td><td>8 (20.5)</td></tr><tr><td>Renal failure, n</td><td>8 (10.3)</td><td>4 (10.3)</td><td>4 (10.3)</td></tr><tr><td>Others, n</td><td>27 (34.6)</td><td>13 (33.3)</td><td>14 (35.9)</td></tr><tr><td><strong>Severity at admission</strong></td><td></td><td></td><td></td></tr><tr><td>SAPS II, points</td><td>39.3<br>(35.2-43.5)</td><td>41.4<br>(34.9-47.8)</td><td>37.2<br>(31.8-42.6)</td></tr><tr><td>Score SOFA, points</td><td>4.2 (3.6-4.8)</td><td>4.3 (3.4-5.2)</td><td>4.2 (3.3-5)</td></tr><tr><td><strong>Baseline parameters</strong></td><td></td><td></td><td></td></tr><tr><td>Pain, points</td><td>2.2 (2.6)</td><td>2.1 (2.7)</td><td>2.2 (2.6)</td></tr><tr><td>Anxiety, points</td><td>4.3 (3.2)</td><td>3.6 (3.2)</td><td>4.9 (3.2)</td></tr><tr><td>Comfort, points</td><td>7.5 (2.7)</td><td>7.4 (2.8)</td><td>7.5 (2.7)</td></tr></tbody></table>

Definitions of abbreviations: BMI, body mass index; SAPS, Simplified Acute Physiologic Score; SOFA, Sequential Organ Failure Assessment; ICU, intensive care unit

<table><caption>**Table 2** Primary and secondary outcomes according to study group</caption><thead><tr><th rowspan="2"></th><th colspan="2">Group</th><th rowspan="2">p value</th><th rowspan="2">Difference (95% CI)</th></tr><tr><th>Hypnosis (n = 39)</th><th>Control (n = 39)</th></tr></thead><tbody><tr><td><strong>Primary outcome</strong></td><td></td><td></td><td></td><td></td></tr><tr><td>Pain at the end of procedure (H0), point</td><td>2.2 (2.9)</td><td>2.2 (3)</td><td>0.8</td><td>0 (-1.3;1.3)</td></tr><tr><td><strong>Secondary outcomes</strong></td><td></td><td></td><td></td><td></td></tr><tr><td>Pain at 1 h, point</td><td>1.8 (2.3)</td><td>2.2 (2.8)</td><td>0.5</td><td>-0.5 (-1.6;0.7)</td></tr><tr><td>Anxiety at the end of procedure (H0), point</td><td>2.4 (2.8)</td><td>4.1 (3)</td><td>0.01</td><td>-1.7 (-3;-0.4)</td></tr><tr><td>Anxiety at 1 h, point</td><td>1.9 (2.6)</td><td>3.2 (3)</td><td>0.048</td><td>-1.3<br>(-2.5;-0.03)</td></tr><tr><td>Comfort at the end of procedure (H0), point</td><td>7.9 (2.3)</td><td>7.9 (2.3)</td><td>0</td><td>0 (-1;1)</td></tr><tr><td>Comfort at 1 h, point</td><td>7.8 (2.3)</td><td>7.7 (2.5)</td><td>0.8</td><td>0.1 (-0.9;1.2)</td></tr><tr><td>Morphine, mg</td><td>0.6 (3.8)</td><td>0.1 (0.6)</td><td>0.5</td><td>-0.5 (-0.7;1.7)</td></tr><tr><td>Midazolam, mg</td><td>0 (0)</td><td>1 (4.5)</td><td>0.2</td><td>-1 (-2.4;0.4)</td></tr><tr><td>Lidocaine, mg</td><td>40.2 (39)</td><td>50.2<br>(39.2)</td><td>0.3</td><td>-10<br>(-27.4;7.3)</td></tr><tr><td>Stress of nurse, point</td><td>0.1 (0.4)</td><td>0.9 (1.5)</td><td>0.003</td><td>-0.8<br>(-1.3;-0.3)</td></tr><tr><td>Duration of procedure, min</td><td>30.2<br>(16.2)</td><td>35.3<br>(20.6)</td><td>0.2</td><td>-5.1<br>(-13.4;3.1)</td></tr><tr><td>Number of attempts</td><td>1.9 (1.8)</td><td>1.8 (1.4)</td><td>0.8</td><td>0.1 (-0.6;0.8)</td></tr><tr><td>ICU length of stay, d</td><td>5.4 (5.5)</td><td>7.2 (10.5)</td><td>0.3</td><td>-1.8 (-5.6;1.9)</td></tr><tr><td>ICU survival, n</td><td>32 (82)</td><td>34 (87)</td><td>0.5</td><td></td></tr></tbody></table>

Definitions of abbreviations: ICU, intensive care unit

catheter and dialysis catheter placement represented the majority of procedures and were performed mainly by junior intensivists (74 (95%)). Only 3 procedures were unsuccessful, and the number of attempts was similar between the 2 groups (1.9 ± 1.8 vs. 1.8 ± 1.4, *p* = 0.78).

### Primary endpoint

The mean difference (SD) in the NRS score (range, 0–10) was not significantly different between the two groups (2.2 ± 2.9 vs. 2.2 ± 3, difference 0 pts [95% CI –1.3; 1.3], *p* = 0.89) (Table 2; Fig. 2).

### Secondary endpoints

Table 2 reports the results of the secondary endpoints. The mean (SD) NRS score was not significantly different between the two groups at 1 h (1.8 ± 2.3 vs. 2.2 ± 2.8, difference –0.4 [–1.6; 0.7], *p* = 0.43) after the end of the procedure (Fig. 2), nor was the cumulative dose of analgesic or sedative drugs. Notably, the total procedure length was not increased by the hypnosis session (30.2 min ± 16.2 vs. 35.3 ± 20.6, difference –5.1 min [–13.4; 3.1], *p* = 0.22).

Interestingly, the level of anxiety was significantly lower in the hypnosis group (2.4 ± 2.8 vs. 4.1 ± 3.0, difference –1.7 [–3; –0.4], *p* = 0.01), as was the level of stress experienced by the ICU nurses (0.1 ± 0.4 vs. 0.9 ± 1.5,

difference –0.8 [–1.3; –0.3], *p* = 0.003) (Fig. 3). After adjustment for the baseline level, the level of comfort of patients undergoing invasive procedures was significantly greater immediately and after 1 h in the hypnosis group, and the level of anxiety remained significantly lower in the hypnosis group (*p* < 0.0001 for both). Finally, 70 (90%) patients received lidocaine during the procedure. While no association was found between the total lidocaine dose and the randomization group, patients in the hypnosis group were three times less likely to require increased lidocaine consumption (odds ratio: 0.3 [0.13–0.84], *p* = 0.02).

### Discussion

We report the results of the first multicenter, prospective, randomized, single-blind clinical trial evaluating the benefit of a hypnosis session in an unscheduled setting in critically ill patients. There was no improvement in the pain level of a hypnosis session assessed immediately after the end of the invasive procedure. However, patients experienced significantly lower anxiety and greater comfort, and healthcare providers experienced a lower level of stress during the procedure. In addition, we demonstrated the feasibility of performing a hypnosis session immediately after its suggestion in critically
<figure><img src="image_4.png" /><figcaption>**Fig. 1** Diagram flowchart of the study patients</figcaption></figure>
<figure><img src="image_5.png" /><figcaption>**Fig. 2** Numeric pain scale assessing pain before (baseline), immediately after (H0) and 1 h (H1) after the end of the invasive procedure in the hypnosis and placebo groups</figcaption></figure>

ill patients undergoing unplanned invasive procedures. To the best of our knowledge, no randomized controlled trial has been conducted in this specific population, thus extending the scope of use of hypnotherapy. For example, Rousseaux et al. recently assessed the impact of virtual reality and/or hypnosis in an ICU setting [10]. However, the included ICU patients underwent planned cardiac surgery, and the hypnosis session consisted of a 20 min prerecorded audio track.

Furthermore, we observed that the total procedure length was not extended by the hypnosis session, despite the 5- to 10-minute setup time potentially increasing the overall duration. This result is consistent with other studies [6, 9]. It is plausible that the added preprocedure time was offset by a shorter duration during the procedure itself due to increased comfort for the patient.

The pain and anxiety experienced by critically ill patients are frequent [3, 15] and could have a significant impact on the course of critically ill patients and their recovery [16]. The adverse effects of pharmacological strategies that are routinely used are frequent and can cause several issues, such as respiratory or hemodynamic failure, delirium and withdrawal syndromes [4]. All these adverse effects are more common in critically ill patients. Therefore, the excessive use of analgesic and sedative drugs can lead to prolonged ICU and hospital

stays, as well as increased healthcare costs. Consequently, nonpharmacological complementary approaches are gaining attention — not as replacements for pharmacological methods but as complementary tools within a broader therapeutic arsenal. Although our study was not designed to detect a difference in analgesic or sedative consumption, several studies reported a reduction in opioid requirements, whereas a recent meta-analysis reported no significant difference [9, 17–19]. In our study, the absence of a significant difference may be due to a low baseline consumption level in both groups and/or a lack of statistical power.

Interestingly, patients in the hypnosis group presented with reduced anxiety and increased comfort compared with those in the standard care group. This aligns with the literature, which consistently reports a reduction in anxiety [20]. For example, the HYPNOSEIN randomized clinical trial [5] reported similar results, with lower anxiety in the hypnosis group than in the control group, although there was no difference in the primary endpoint, which was breast pain. These outcomes suggest that anxiety or comfort could be valuable primary endpoints in future studies to better assess the benefits of hypnosis. In our study, the lack of difference in pain levels may be due to the relatively low pain intensity of the procedures performed, suggesting that comfort might be
<figure><img src="image_6.png" /><figcaption>**Fig. 3** Numeric anxiety and stress scales assessing respectively anxiety in critically ill patients undergoing unplanned invasive procedures (A) and stress in caregivers (B) before, immediately after (H0) and 1 h (H1) after the end of the invasive procedure in the hypnosis and placebo groups, respectively</figcaption></figure>

<figure><img src="image_7.png" /></figure>

a more relevant measure of the impact of hypnosis in this setting.

Moreover, we found that although nurses' stress levels were initially low, they were still significantly reduced by the hypnosis session, despite nurses not being the primary target of the intervention. To our knowledge, this is the first study to report such an effect of hypnosis in ICU caregivers. We could explain this result by a more peaceful environment during the hypnosis sessions, facilitating their work, and by the belief that patient pain and anxiety would be better considered. This finding is important, as several studies have emphasized the importance of work-related stress in job satisfaction and avoidable errors [21–23], which could be dramatic for critically ill patients.

Our study has several limitations. Blinding may have reduced the effect of hypnosis due to the influence of hypnotic suggestion. Additionally, participation in the study might have led to behavioral changes among the medical and paramedical teams, potentially resulting in increased empathy in the care of patients, particularly those in the control group. However, we tried to avoid these biases by the presence of the same number of healthcare providers regardless of the randomization group.

## Conclusion

Among critically ill patients who underwent an unplanned invasive procedure in the ICU, hypnosis did not result in a statistically significant reduction in procedural pain. However, hypnosis seemed to reduce anxiety, increase comfort, and reduce the stress level of healthcare providers. Further studies should focus on anxiety or comfort level as primary endpoints, and also consider qualitative outcomes to explore patient experience, acceptability, and satisfaction with hypnosis in the ICU.

## Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s13054-025-05563-9.

Supplementary Material 1.

Supplementary Material 2.

Supplementary Material 3.

Supplementary Material 4.

## Acknowledgements

Not applicable.

## Author contributions

AM, CF and BL conceptualized the study and its design, data acquisition and analysis, literature research. PF, MPA, MA, AV, KP, MD, NM, MR, NM and NP participated in data acquisition. NT, AG, JMT and BL participated in manuscript
drafting and revision for important intellectual content. AM obtained funding. All the authors read and approved the final manuscript.

## Funding

Programme hospitalier de Recherche Infirmière et Paramédicale 2018, Ministère de la Santé, France (PHRIP-18-0299).

## Data availability

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request. Data are located in controlled access data storage at CHU Rennes.

## Declarations

### Ethics approval and consent to participate

The trial was approved for all centers by a central Ethics Committee (IDCRB 2019-A01775-52, Comité de Protection des Personnes Bron —Région SUD-EST II, France) according to French law on October 9, 2019. This study was conducted in accordance with the ethical standards of the Declaration of Helsinki and the Good Clinical Practice requirements. Written informed consent was required for all patients prior to enrollment and randomization.

### Consent for publication

Not applicable.

### Competing interests

The authors declare no competing interests.

### Author details

Received: 9 April 2025 / Accepted: 9 July 2025

Published online: 18 July 2025

## References

1. Pottier V, Daubin C, Lerolle N, Gaillard C, Viquesnel G, Plaud B, et al. Overview of adverse events related to invasive procedures in the intensive care unit. Am J Infect Control. 2012;40:241–6.

2. Devlin JW, Skrobik Y, Gélinas C, Needham DM, Slooter AJC, Pandharipande PP, et al. Clinical practice guidelines for the prevention and management of pain, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU. Crit Care Med. 2018;46:e825–73.

3. Puntillo KA, Max A, Timsit J-F, Vignoud L, Chanques G, Robleda G, et al. Determinants of procedural pain intensity in the intensive care unit. The Europain* study. Am J Respir Crit Care Med. 2014;189:39–47.

4. de Jong A, Molinari N, de Lattre S, Gniadek C, Carr J, Conseil M, et al. Decreasing severe pain and serious adverse events while moving intensive care unit patients: a prospective interventional study (the NURSE-DO project). Crit Care. 2013;17:R74.

5. Amraoui J, Pouliquen C, Fraisse J, Dubourdieu J, Rey Dit Guzer S, Leclerc G, et al. Effects of a hypnosis session before general anesthesia on postoperative outcomes in patients who underwent minor breast Cancer surgery: the HYPNOSEIN randomized clinical trial. JAMA Netw Open. 2018;1:e181164.

6. Montgomery GH, Bovbjerg DH, Schnur JB, David D, Goldfarb A, Weltz CR, et al. A randomized clinical trial of a brief hypnosis intervention to control side effects in breast surgery patients. J Natl Cancer Inst. 2007;99:1304–12.

7. Liossi C, Hatira P. Clinical hypnosis in the alleviation of procedure-related pain in pediatric oncology patients. Int J Clin Exp Hypn. 2003;51:4–28.

8. Montgomery GH, David D, Winkel G, Silverstein JH, Bovbjerg DH. The effectiveness of adjunctive hypnosis with surgical patients: a meta-analysis. Anesth Analg. 2002;94:1639–45. table of contents.

9. Garcia R, Bouleti C, Li A, Frasca D, El Harrouchi S, Marechal J et al (2020). Clinical Electrophysiology

10. Rousseaux F, Dardenne N, Massion PB, Ledoux D, Bicego A, Donneau A-F, et al. Virtual reality and hypnosis for anxiety and pain management in intensive care units: A prospective randomised trial among cardiac surgery patients. Eur J Anaesthesiol. 2022;39:58–66.

11. World Medical Association. World medical association declaration of helsinki: ethical principles for medical research involving human subjects. JAMA. 2013;310:2191–4.

12. Agency EM. ICH E6 Good clinical practice - Scientific guideline| European Medicines Agency (EMA) [Internet]. 2025 [cited 2025 Mar 24]. Available from: https://www.ema.europa.eu/en/documents/scientific-guideline/ich-e6-r3-gunderline-good-clinical-practice-gcp-step-5_en.pdf

13. Puntillo KA, White C, Morris AB, Perdue ST, Stanik-Hutt J, Thompson CL, et al. Patients' perceptions and responses to procedural pain: results from thunder project II. Am J Crit Care. 2001;10:238–51.

14. Morrison RS, Ahronheim JC, Morrison GR, Darling E, Baskin SA, Morris J, et al. Pain and discomfort associated with common hospital procedures and experiences. J Pain Symptom Manage. 1998;15:91–101.

15. Chanques G, Sebbane M, Barbotte E, Viel E, Eledjam J-J, Jaber S. A prospective study of pain at rest: incidence and characteristics of an unrecognized symptom in surgical and trauma versus medical intensive care unit patients. Anesthesiology. 2007;107:858–60.

16. Skrobik Y, Ahern S, Leblanc M, Marquis F, Awissi DK, Kavanagh BP. Protocolized intensive care unit management of analgesia, sedation, and delirium improves analgesia and subsyndromal delirium rates. Anesth Analg. 2010;111:451–63.

17. Akgul A, Guner B, Çırák M, Çelik D, Hergünsel O, Bedirhan S. The beneficial effect of hypnosis in elective cardiac surgery: A preliminary study. Thorac Cardiovasc Surg. 2016;64:581–8.

18. Chapet O, Udrescu C, Horn S, Ruffion A, Lorchel F, Gaudioz S, et al. Prostate brachytherapy under hypnosedation: A prospective evaluation. Brachytherapy. 2019;18:22–8.

19. Provençal S-C, Bond S, Rizkallah E, El-Baalbaki G. Hypnosis for burn wound care pain and anxiety: A systematic review and meta-analysis. Burns. 2018;44:1870–81.

20. Kekecs Z, Nagy T, Varga K. The effectiveness of suggestive techniques in reducing postoperative side effects: a meta-analysis of randomized controlled trials. Anesth Analg. 2014;119:1407–19.

21. Tarnow-Mordi WO, Hau C, Warden A, Shearer AJ. Hospital mortality in relation to staff workload: a 4-year study in an adult intensive-care unit. Lancet. 2000;356:185–9.

22. West CP, Huschka MM, Novotny PJ, Sloan JA, Kolars JC, Habermann TM, et al. Association of perceived medical errors with resident distress and empathy: a prospective longitudinal study. JAMA. 2006;296:1071–8.

23. West CP, Tan AD, Habermann TM, Sloan JA, Shanafelt TD. Association of resident fatigue and distress with perceived medical errors. JAMA. 2009;302:1294–300.

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<footnote n="1">¹Service des Médecine intensive - Réanimation, Univ Rennes, CHU Rennes, Rennes F-35000, France</footnote>

<footnote n="2">²Service de Réanimation Polyvalente, CH Saint Brieuc, Saint Brieuc, France</footnote>

<footnote n="3">³Centre d'investigation Clinique de Rennes), Service de Pharmacologie Clinique, Univ Rennes, CHU Rennes, Inserm, Rennes 1414, F-35000, CIC, France</footnote>

<footnote n="4">⁴Service des Maladies infectieuses et réanimation médicale, Hôpital Pontchaillou, 2, rue Henri Le Guilloux, Rennes cedex 9 35033, France</footnote>