Nurses’ perceived feasibility and the clinical utility of the Nociception Level (NOL™) Index for pain assessment in critically ill adults

Abstract

Introduction: The Nociception Level (NOL™) Index monitors nociception and related pain using multiple physiologic parameters through a non-invasive finger probe and is currently undergoing validation for pain assessment in the Intensive Care Unit (ICU). This study aimed to describe its feasibility and clinical utility from nurses’ perspectives, which is crucial for its potential adoption in clinical practice.

Methods: This descriptive study involved ICU nurses who received a brief training (5-minute video and handout) as part of the validation process of the NOL Index in a medical-surgical ICU. Trained nurses who used the NOL Index at the ICU bedside completed a self-administered questionnaire on its feasibility and clinical utility on a 4-point scale. Scores of 3 and 4 supported its feasibility and clinical utility.

Results: Of the 21 trained nurses, nine (43%) used the NOL on enrolled patients, but eight (38%) completed the questionnaire.

Their average age was 34 years, and 63% were female. Feasibility indicators were endorsed by 95% of nurses supporting the NOL’s easy application, installation, and calibration, with clear usage instructions. Training strategies (i.e., video and handout) were rated positively with scores ≥ 3/4 by 95% of nurses. Nurses recommended adding more hands-on practice for the bedside use of the NOL. Clinical utility indicators were endorsed by 87.5 % of nurses suggesting it should remain an assistive, not a diagnostic tool. Indeed, several factors including patient’s hemodynamic instability and movements limit the NOL Index’s use in the ICU.

Conclusion: Nurses perceived the NOL Index as a potential alter- native measure for pain assessment in mechanically ventilated and sedated ICU patients unable to self-report.

Keywords: feasibility, clinical utility, nociception, pain assessment, intensive care unit

Shahiri, S., Lavoie, P., Martel, M. O., Richebé, P., & Gélinas, C. (2025). Nurses’ perceived feasibility and the clinical utility of the Nociception Level (NOL™) Index for pain assessment in critically ill adults. The Canadian Journal of Critical Care Nursing, 36(2), 6–17. DOI: 10.5737/23688653-3626

Implications for Nursing

• The Nociception Level (NOL) Index, a multiparametric technology initially developed for use during anesthesia, is being validated for ICU pain assessment.
• During the validation process, it is critical to evaluate the new tool’s usage feasibility and clinical utility from nurses’ perspectives.
• Nurses considered the NOL Index a potential alternative measure for pain assessment in mechanically ventilated and sedated ICU patients, contingent upon addressing clinical factors (e.g., hemodynamic instability, and movements) that limit its use.

Introduction

Nurses in the intensive care unit (ICU) provide complex care to critically ill adults who suffer from severe illnesses, trauma, and surgery. These conditions expose them to pain caused by nociception from tissue damage, invasive interventions, and noxious stimuli from standard care procedures (Devlin et al., 2018). While patient self-report is the reference standard measure of pain, the use of sedative medications, mechanical ventilation, or clinical conditions affecting brain functioning may hinder self-reporting (Devlin et al., 2018).

In such cases, nurses use behavioural assessment tools as alter- native standard pain measures, such as the Behavioral Pain Scale (BPS; Payen et al., 2001) and the Critical-Care Pain Observation Tool (CPOT; Gélinas et al., 2006). However, these tools cannot be used in patients on high doses of sedatives or neuromuscular blockers as they become unresponsive to stimulation (Chanques et al., 2020; Devlin et al., 2018; Herr et al., 2024). Thus, exploring alternative pain assessment methods is necessary.

Continuous bedside monitoring provides immediate access to vital signs. ICU nurses use vital signs for various purposes including pain assessment (Damico et al., 2016; Gnass, 2015; Rose et al., 2012). However, evidence has demonstrated that individual vital signs lack validity for ICU pain assessment purposes (Devlin et al., 2018; Herr et al., 2024; Shahiri & Gélinas, 2023). Studies in the field of anesthesia have shown that the combination of multiple physiologic parameters (e.g., heart rate, blood pressure) may be superior to their individual use for nociception monitoring (Ben-Israel et al., 2013; Edry et al., 2016; Martini et al., 2015; Renaud-Roy et al., 2019; Stockle et al., 2018). The developed Nociception Level (NOL™) Index (Medasense Biometrics Ltd., 2025) simultaneously incorporates multiple physiologic parameters captured from a non-invasive finger probe to monitor nociception and pain in anesthetized patients (Ben-Israel et al., 2013). The finger probe incorporates a disposable sensor that extracts several physiologic parameters, including heart rate, heart rate variability, photoplethysmography pulse wave amplitude (an indicator of arterial blood pressure), and skin conductance and temperature (Ben-Israel et al., 2013; supplementary file A). Values exceeding 20–25 were found to be indicative of nociception and pain (Coulombe et al., 2021; Gélinas et al., 2021; Ledowski et al., 2021; Meijer et al., 2020; Renaud-Roy et al., 2019). Since a tool can only be valid for a specific population and in a given context (Streiner et al., 2024), the validation of the NOL Index for pain assessment in critically ill adults in the ICU setting was necessary. We conducted two initial pilot studies in 54 conscious postoperative ICU cardiac patients and 15 conscious mechanically ventilated ICU patients able to self-report (Gélinas et al., 2021; Shahiri et al., 2020). Our findings supported the NOL Index’s ability to detect pain using standard pain measures including self-reporting (reference standard) and CPOT (alternative standard). Our findings also supported the NOL Index’s ability to discriminate between non-nociceptive (e.g., taking blood pressure using cuff inflation) and nociceptive procedures part of ICU standard care (e.g., chest tube removal, endotracheal/tracheal suctioning; Gélinas et al., 2021; Shahiri et al., 2020).

Evaluating feasibility and clinical utility in the early stage of the validation process is crucial to ensuring comprehensive consideration for future development and implementation (Eysenbach et al., 2018). Feasibility refers to the ease of technology’s clinical application, while clinical utility pertains to the relevance of technology’s use for clinical practice purposes (Duhn & Medves, 2004; Smart, 2006; Weiner et al., 2017). Evidence supports that frontline clinicians such as nurses, should play a role in designing, developing/validating, pur- chasing, implementing, and evaluating healthcare technologies (Lambert et al., 2023; Schoville & Titler, 2015; Weiner et al., 2017), as neglecting their involvement may hinder future adoption in clinical practice (Schoville & Titler, 2015). Therefore, the evaluation of the NOL Index’s feasibility and clinical utility during the validation process could guide technology adoption decisions and evidence-based clinical recommendations (Weiner et al., 2017). This study aimed to describe the feasibility and clinical utility of the NOL for ICU pain assessment from nurses’ perspectives.

Methods and materials

Study design and setting

A descriptive design was used to achieve the study purpose. This study was conducted as a complementary objective of a larger research project focused on validating the NOL for ICU pain assessment across three medical-surgical ICUs of university-affiliated hospitals in Montreal, Canada. The present study was conducted in one of these ICUs, which has a 30-bed capacity. However, due to nursing shortage caused by the COVID-19 pandemic, the number of available beds was reduced to 20, with 15 nurses per shift during the study period. On average, the ICU admits between 1,000 and 1,500 patients annually. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was used for the description of the study and the reporting of the results (von Elm et al., 2007).

Participants

Two populations were recruited for the larger research project: nurse and patient participants. The present study focuses exclusively on nurse participants. The eligibility criteria for patient participants are provided because they were under the care of the nurse participants who tested the NOL Index on them.

Convenience sampling was used to recruit nurse participants, which was well aligned with our aim to obtain an overview of the perspectives and insights from ICU nurses involved in the NOL Index validation study. Nurses with part-time and full- time positions and a minimum experience of 6 months were eligible, as this period is required to complete orientation and probation.

Enrolled ICU patients under the care of the nurse participants were: ≥18 years old, English, or French speaking, and mechanically ventilated. They were excluded if they had conditions that could affect the NOL Index signal, such as hemodynamic instability (e.g., cardiac arrhythmias, severe peripheral vascular disease, state of hypoperfusion, or receiving high doses of vasopressors) or movements or agitation.

Recruitment procedures

Ethical approval was submitted in February 2022 and approved in June 2022 (project # MP-05-2022-2988). The research trainee (SS) presented the study to ICU nurses during staff meet- ings. The study description and invitation were also emailed to all ICU nurses by the nurse clinical consultant. Nurses who expressed interest during the staff meeting, on the unit during the data collection, or via email were contacted by the research trainee for additional study details. The research trainee confirmed eligibility, addressed questions, and provided explanations about the study and consent form. A screening log was maintained, documenting the number of nurses who agreed to participate, and reasons for refusal or withdrawal.

Data collection procedures

Training of nurse participant for NOL study procedure

The research trainee provided the training to nurse participants before the NOL study procedure at the ICU bedside. Nurse participants watched a 5-minute training video in mp4 format prepared by the research trainee and reviewed by the principal investigators (CG and PR), which was accompanied by a handout detailing the NOL Index’s description, function, and measurement method. These materials were sent to the nurses via email. The training video encompassed all information covered in the handout, along with a demonstration of NOL Index device setup, including finger probe placement and calibration. The research trainee addressed any questions, provided a concise review of the steps, and offered additional clarification as needed until the nurse participant felt prepared to proceed. A checklist was provided to assist in the NOL procedure, and the research trainee completed it during the process. Throughout the data collection of the NOL study procedure, the research trainee was present and available to address any questions from the nurse participants.

NOL Index procedure by nurse participants

The data collection of the NOL study procedure took place from July 2022 to March 2023. Once an ICU patient was enrolled and under the care of a nurse participant, the research trainee informed the nurse about the start of the data collection procedure. First, the NOL’s training content and the procedure steps were reviewed with the nurse participant. Then, the nurse installed the disposable sensor in the finger probe and placed it on the patient’s index finger or any available finger. Subsequently, the nurse performed bedside calibration of the NOL device and observed NOL values before and during mouth/endotracheal/ tracheal suctioning. This intervention was selected as the nociceptive procedure because it is known to induce moderate to severe pain (Dale et al., 2020; Dale et al., 2018; Kurt & Zaybak, 2022; Özsaban et al., 2023; Puntillo et al., 2014) and is part of standard care for mechanically ventilated ICU patients. The suctioning procedures were performed by respiratory therapists based on patients’ care needs. Considering that the NOL is still in the validation process, it was emphasized that NOL values should not influence nurses’ decision-making regarding the administration of analgesia during this study. The research trainee was present to verify proper probe placement and device calibration, ensuring accurate device application by the nurse participants (Bialocerkowski et al., 2010). The nurse participants had the opportunity to address questions to the research trainee during the procedures, if required.

Upon completion of training and all steps of the NOL study procedure for an enrolled patient, the nurse participants were asked to fill out demographic, and feasibility and clinical utility questionnaires and returned them in a sealed envelope to the research staff within a 72-hour period. A small compensation of 40 CAD was offered to nurses for their participation upon returning their completed questionnaire. It is noteworthy that prior to being part of the present study, nurse participants also had exposure to observing other instances in which the research staff performed data collection during the validation study, including any challenges encountered during the NOL study procedure.

Instruments

Socio-demographic information from nurse participants

The socio-demographic questionnaire included information on participants’ age, sex, gender, and educational level. The following data on professional experience were also collected: ICU position, current employment status, years in the current ICU position, and total years of experience in nursing.

Feasibility and clinical utility questionnaire

The self-administered Feasibility and Clinical Utility questionnaire comprised 13 closed-ended questions presented on a descriptive scale ranging from 1 to 4, where 1 indicates “Not at all”, 2, indicates “A little”, 3 indicates “Sufficiently” and 4 indicates “Very”. Therefore, we considered scores of 3 and 4 as endorsements of feasibility and clinical utility. The questionnaire was adapted from prior versions assessing CPOT feasibility and clinical utility (Gélinas, 2010; Gélinas et al., 2011; Richard-Lalonde et al., 2019) which was initially developed by Puntillo et al. (2002) for their pain assessment tool (Pain Assessment and Intervention Notation [P.A.I.N.]). Feasibility indicators (n = 5) included duration of training, quickness of use, clarity in NOL application, comprehensibility, and simplicity of completion. Clinical utility indicators (n = 3) addressed the recommendation of the NOL’s use, its helpfulness, and its potential influence on clinical practice. Additional questions (n = 5) were created to assess specific aspects of the training, such as the effectiveness of the training handout and video, as well as the support provided by the research team. Each question allowed for short comments to provide additional context to ratings. Furthermore, open-ended questions were included to gather insights for potential future implementation of the NOL into practice. The questionnaire was available in both English and French to accommodate participants’ language preferences.

NOL Index procedure checklist

A checklist was designed to guide the NOL study procedure. It included six steps for the nurse participants to follow: 1) instal- lation of disposable sensor on the finger probe; 2) placement of the non-invasive finger probe on any available finger of the patient; 3) turning on the NOL Index device; 4) calibrating the NOL Index by pressing the calibration button; 5) obtaining the NOL Index signal; 6) reading the NOL Index value.

Data analysis

Descriptive statistics, including frequencies and medians (inter- quartile intervals), were reported using SPSS 27 to characterize the study sample and nurses’ responses to the questionnaires. The frequency and percentage of nurses who provided a score of 3 or 4 for each aspect of the NOL’s use (i.e., feasibility, training, and clinical utility) were also calculated. Written responses were categorized by topics and arranged in the order of occurrence frequency.

Results

All 21 ICU nurses who were interested and approached agreed to participate and were trained to use the NOL. The participant flow diagram is provided in Figure 1.

Out of the 21 nurses trained to perform the NOL study procedure, 12 (57%) did not complete the bedside data collection procedure during validation testing. Among them, nine never had the opportunity to perform the NOL study procedure at the ICU bedside since no patient under their care was enrolled in the validation study. For the remaining three nurses, the NOL Index signal failed to generate in two cases, potentially due to factors such as sudden changes in cardiac rhythms during the procedure or cold fingers. In the third case, the nurse was on a break during the suctioning procedure, but the replacement nurse, also a nurse participant, completed the procedure. Consequently, those three were unable to complete the NOL study procedure at the bedside and, therefore, were not asked to fill out the feasibility and clinical utility questionnaire. None of these nurses had the opportunity to retry with another patient participant.

Nine nurses (43%) successfully completed the NOL study procedure at the bedside. Among them, two achieved successful data collection on a second attempt with another patient participant due to initial signal loss on their first patient participant. For one of the nurse participants, the patient participant experienced sudden onset of irregular cardiac rhythm at the time of procedure, leading to the NOL signal not generating. This condition was also an exclusion criterion due to its impact on heart rate variability, a parameter crucial to the NOL algorithm. Therefore, the patient participant was excluded. For the other nurse participant, signal loss may have been due to the patient’s cold finger. One nurse participant left the hospital prior to returning the completed questionnaire and was unreachable. Thus, eight nurses returned their completed questionnaire.

Socio-demographics of nurse participants

The sociodemographic information of the nurse participants is presented in Table 1. The nurses’ median age was 39 years (range = 25–60). As a complementary analysis, we performed the Mann-Whitney U test to examine if age, number of years in the current ICU position, and total years of experience in nursing were different between nurses who completed the NOL Index procedure at the bedside and those who did not. The age of nurses who completed the NOL study procedure (n = 8) versus those who did not (n = 9) was not significantly different (U = 48.00, p = .277). Educational level was similar for nurses who used the NOL and those who did not. However, they were significantly different in their number of years in the current ICU position (U = 45.00, p = .036) and total years of nursing experience (U = 59.50, p = .021), indicating that nurses who completed the NOL study procedure were less experienced.

Socio-demographics of patient participants under the care of nurse participants

Thirteen patients were cared for by nurse participants over the course of the study. Among these, a NOL signal was successfully generated in nine patients, but not in four. For the nine patients for whom the NOL signal was generated, the median age was 71 years (range = 46–79, IQR = 61–74). The majority were male (n = 7) and mechanically ventilated (n = 8). One patient participant was extubated at the time of the nurse participant’s data collection; however, mouth suctioning was performed, and the nurse participant was able to complete the NOL procedure. Patient participants were admitted to the ICU with a medical (n = 2) or a surgical (n = 7) diagnosis. Six patients had no alteration of consciousness (Glasgow Coma Scale [GCS] = 13–15; Teasdale & Jennett, 1974), while three had an altered level of consciousness (GCS = 6–11). For the four patient participants for whom the NOL Index signal did not generate, the median age was 72 (range = 59–75, IQR = 65–74). Two were female. All four were conscious (GCS = 13–15), mechanically ventilated, and admitted to the ICU with a surgical diagnosis.

NOL Index feasibility and clinical utility

All the steps of the NOL study procedure checklist were successfully achieved per nurse participants (n = 8). On three occasions, the nurse participants asked the research trainee to turn on the NOL device or press the calibration button, because they were on the other side of the bed and away from the device. Results from the evaluation of feasibility and clinical utility of the NOL are presented in Table 2 and written comments provided by the nurse participants are presented in Table 3. All nurse participants completed the English version of the questionnaire.

Feasibility indicators and training strategies were endorsed by 95% of nurses, indicating easy application of the finger probe, installation, and calibration of the NOL. Nurses indicated that the support from the research staff during training and their presence during the NOL study procedure were the most helpful training strategies. Moreover, they stated the real-time demonstration was a better training strategy than the recorded video. More exposure and practice with the NOL were also requested.

Clinical utility indicators were endorsed by 87.5 % of nurses. Nurses indicated that the NOL, if found valid, could provide an alternative measure for pain assessment and guide analgesic effectiveness evaluation in mechanically ventilated and sedated ICU patients. They further mentioned that by optimizing analgesia, the NOL may help to decrease the length of ICU stay and improve patient outcomes. However, they also pointed out that impeding factors, such as agitation, cardiac arrhythmias, edema, state of shock, and movements may hinder its utility in the ICU context. Another concern was raised regarding whether the NOL Index detects only pain or related emotions, such as fear and anxiety. Lastly, they suggested that the NOL should remain as an assistive technology and not a diagnostic tool.

To improve the clinical utility of the NOL in the ICU setting, nurses recommended integrating the NOL into the ICU bedside monitoring device. In some instances, nurses had difficulty placing the finger probe. Thus, they also recommended providing different sizes and shapes of the NOL’s finger probe as it exists for oxygen saturation finger probes. Finally, the strategies for potential future NOL’s implementation into ICU clinical practice were described in Table 4.

Discussion

Nurses’ perceived feasibility and clinical utility of the NOL was evaluated for the first time within the context of its validation process. Almost half of the nurse participants who were trained had the opportunity to perform the NOL procedure at least once at the ICU bedside. They also observed the research staff performing NOL data collection during the validation study, which could have influenced their evaluations. The majority of nurses who completed the NOL procedure in this study are considered as expert in their professional development (Benner, 1982). Research has shown that greater clinical experience is associated with a higher likelihood of utilizing technology at the bedside (Brown et al, 2020). Thus, nurses with greater clinical experience may be more likely to incorporate bedside technology effectively into patient care.

Most ICU nurse participants agreed with all feasibility indicators assessed. The NOL was perceived as easy and quick to use and understand, and simple and quick to apply with clear directives for application. While support from the research staff was considered the most helpful training strategy, nurses recommended incorporating real-time demonstrations and multiple opportunities for practice with the NOL into training sessions.

Nurses pointed out several factors that may limit the clinical utility of the NOL for ICU pain assessment, including patient movement, agitation, cardiac arrhythmias, and edema. Our previous findings also highlighted the potential impact of patient movements on NOL signal quality, which was mitigated by instructing participants to limit finger movement during data collection, as they were all awake and conscious during these pilot studies (Gélinas et al., 2021; Shahiri et al., 2020). Yet, in agitated ICU patients who are not sedated, the NOL’s clinical utility is likely to be compromised. Given that most patient participants in this study were conscious, nurses likely found it easier to identify issues primarily related to patient movement. Cardiac arrhythmias, although an exclusion criterion from the validation study, are common in critically ill patients and can affect heart rate variability (one of the parameters of the NOL algorithm), potentially leading to signal loss and limiting its use in the ICU. Similarly, edema can affect photoplethysmography outputs, posing challenges for patients with swollen fingers. Similar findings regarding NOL signal issues compromising its clinical utility in the ICU were also reported in our pilot stud- ies. These issues included variability in the shapes and sizes of patients’ fingers, as well as patient movements (Gélinas et al., 2021; Shahiri et al., 2020). According to the nurses’ suggestions, some of these challenges could be addressed by enhancing the finger probe design to accommodate a wider range of finger sizes and shapes.

To address nurses’ concerns about whether the NOL detects only pain or other distressful feelings, our pilot study with post- operative ICU cardiac patients found associations between NOL values and pain intensity, but not anxiety (Gélinas et al., 2021). Mechanically ventilated ICU patients often experience distressing symptoms, such as anxiety and fear (Guttormson et al., 2023). Certainly, the coexistence of pain, fear, and anxiety high- lights the necessity for using assessment tools that exhibit greater sensitivity and specificity to pain (Gélinas et al., 2014). Further validation results may elucidate this concern.

Implementation strategies suggested by nurses could assist in determining suitable implementation frameworks in ICU clinical practice for the NOL (Moullin et al., 2020). The suggested strategies in this study align with the refined Expert Recommendations for Implementing Change in the ICU frame- work, which include conducting ongoing and dynamic training sessions, educational meetings, identifying and preparing champions, offering interactive assistance, and involving executive boards (Mosch et al., 2022).

Limitations

This study had some limitations. Firstly, the participation rate was lower than anticipated compared to the total number of ICU nurses who received training. This was primarily due to trained nurses not being assigned to enrolled patients and one being on break during data collection. Secondly, the group of nurse participants who did not have the opportunity to perform the NOL study procedure at the bedside had more clinical experience than those who did, potentially affecting additional comments or insights. However, this assignment occurred randomly as the nurse and patient assignments were not con- trolled in this study but were determined by the assistant nurse manager. Thirdly, nurses could only complete the questionnaire after all steps of the NOL study procedure, so no data is available for instances where the NOL signal did not generate, and these nurses did not have a second opportunity. Fourthly, missing data occurred due to nurses leaving their positions in the ICU post-pandemic crisis. Finally, the questionnaire relied on quantitative evaluation of specific feasibility and clinical utility indicators, with the option to provide additional writ- ten comments. Further research with qualitative methods, such as semi-structured interviews could allow nurses to expand on their perspectives on the use of the NOL in the ICU.

Conclusions

During the validation process of the NOL Index, nurse participants positively evaluated the feasibility of using the NOL Index in the ICU setting. However, the clinical utility of the NOL Index was hindered by factors such as cardiac arrhythmias, edema, and the state of shock as experienced by ICU nurse participants in enrolled ICU patients. As the NOL Index validation process for ICU pain assessment is still ongoing, feedback from bedside clinicians, such as ICU nurses, can inform improvements to the NOL Index device to address these challenges. If NOL Index is found to be valid for ICU pain assessment, further implementation studies are warranted to evaluate the feasibility and clinical utility of this technology in routine clinical practice, its effects on pain management protocols, and patient outcomes.

Author notes

• Shiva Shahiri T., MScA, RN, Ingram School of Nursing, McGill University. Centre for Nursing Research and Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
• Patrick Lavoie, PhD, RN, Faculty of Nursing, Université de Montréal, Montreal, Quebec, Canada and Montreal Heart Institute Research Centre, Montreal, Quebec, Canada.
• Marc O. Martel, PhD, Faculty of Dental Medicine and Department of Anesthesiology, McGill University, Montreal, Quebec, Canada.
• Alan Edwards, Pain Management Unit, McGill University Health Centre, Montreal, Quebec, Canada.
• Philippe Richebe, MD, PhD, DESAR, Département d’anesthésie et réanimation, Polyclinique Bordeaux Nord Aquitaine, Bordeaux, France Department of Anesthesiology and Pain Medicine, Université de Montréal, Montreal, Quebec, Canada.
• Céline Gélinas, PhD, RN, FCAN, Ingram School of Nursing, McGill University. Centre for Nursing Research, and Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.

Corresponding Author: Shiva Shahiri T., MScA, RN, Ingram School of Nursing, McGill University. Centre for Nursing Research and Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada. Email: shiva.shahiri@mail.mcgill.ca

Funding and conflict of interest

The authors acknowledge that Shiva Shahiri T. has been supported by doctoral awards from the Fonds de Recherche du Québec-Santé (FRQS), the Quebec Network on Nursing Intervention Research (RRISIQ), and Ministère de l’Enseignement Supérieur de la Recherche et de la Science (MES). The validation study of the NOL Index is primarily funded by the Canadian Institutes of Health Research (CIHR Project Grant #168983) led by Céline Gélinas (principal investigator) and Philippe Richebé (co-principal investigator).

Shiva Shahiri T. is a graduate research trainee on this major grant and obtained research stipend. The funding agencies were not involved in the preparation of the research protocol or in the writing of this paper.

Medasense Biometrics Ltd. has not been involved in any part of the NOL Index validation study or the present study. The NOL Index device was purchased using CIHR funds to ensure complete independence.

The authors declare no known conflicts of interest.

Figure 1

Nurse Participants Flow Diagram

Note. NOL = Nociception Level Index

Table 1

Sociodemographic Information of Nurse Participants (n = 21)

Note. Values are median (IQR) or n (%).

*One nurse left the hospital and did not complete the questionnaire.

#Three nurses left the hospital without completing the NOL procedure, having only filled out the socio-demographic questionnaire.

NOL = Nociception Level Index; ICU = intensive care unit.

Table 2

Nurse Participants’ Responses to the Questionnaire Regarding Feasibility, Training Evaluation, and Clinical Utility of the NOL (n = 8)

practice

Note. NOL = Nociception Level Index.

Table 3

Nurse Participants’ Comments on Feasibility and Clinical Utility of the NOL for ICU Pain Assessment

Comments                                                                                        Frequency

The NOL Index is quick and easy to use

Easy and quick installation, application, and calibration                                                                                                             4

Directive about the use of the NOL

Very clear directive                                                                                                                                                                        2

Most helpful training strategies

Reasons for recommending the use of the NOL

Provides an alternative pain measure for non-communicative ICU patients who are non-agitated and sedated                    8

Reasons for not recommending the use of the NOL

Inaccurate readings on restless ICU patients or during movement                                                                                            1

The NOL Index is not suitable during acute phase of a shock (e.g., sepsis) or on patients with edema on their fingers              1

There is a concern whether the NOL detects only pain or other emotions such as fear and anxiety                                        1

The NOL is helpful for practice

The NOL provides another quantitative measure of pain other than vital signs                                                                        1

The NOL seems to be a helpful alternative measure of pain in non-communicative, sedated, and mechanically               5

ventilated patients

The NOL is helpful to evaluate the effectiveness of treatment in sedated and mechanically ventilated patients                          1

The NOL is not helpful for practice

Anxiety seems to influence the NOL’s reading; the NOL Index values increased on an awake patient who self-re-               1

ported being anxious but not being in pain

The NOL signal does not generate on ICU patients with complex clinical conditions (e.g., state of shock, cardiac               1

arrhythmias, edema).

Using the NOL in the study has influenced my practice in assessing the patient’s pain

The NOL would enable clinicians to optimize pain management and to avoid over-/under treatment                                   4

The NOL would help decreasing the length of mechanical ventilation and ICU stay and subsequently lower the               1

incidence of delirium

Using the NOL in the study has not influenced my practice in assessing the patient’s pain

The NOL would remain a tool and not to diagnose pain                                                                                                            1

How to improve the use of the NOL

Integrate the NOL into the ICU beside VS monitoring device                                                                                                   1

Provide different types/sizes for the finger probe                                                                                                                         1

Unsure at this point                                                                                                                                                                       1

Note. NOL = Nociception Level Index; ICU = intensive care unit.

Table 4

Nurse Participants’ Recommended Implementation Strategies of the NOL Index for ICU Pain Assessment

Comments                               Frequency

Note. NOL = nociception level; ICU = intensive care unit.

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Supplementary File A

Nociception Level (NOL)TM Index (Medasense Biometrics Ltd., Ramat Gan, Israel)

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