Methods of Assessing Postoperative Pain in Infants (0–12 Months): A Scoping Review

ABSTRACT

Infants undergoing surgery experience postoperative pain beyond acute short‐lasting procedural pain and have variable analgesic needs. Assessing pain in this nonverbal population presents challenges for clinicians and parents. Given the short‐ and long‐term effects of pain and its treatment, timely and accurate assessment of pain is vital. The aim of this scoping review was to map pain assessment methods used by clinicians and parents to assess postoperative pain in infants aged 0 to 12 months and describe their psychometric properties. The review was guided by Arksey and O'Malley's (2005) five‐stage framework. We searched Embase, Medline, PsycINFO, Scopus, Cochrane, CINAHL from January 2014 to March 2026 to retrieve eligible studies. Thirty‐five studies (four systematic reviews, eight trials, and 23 original research studies) were included. We identified 20 different pain assessment methods used by clinicians. Postoperative pain categorization was inconsistent and lacked clear differentiation. There were inconsistencies in the duration, frequency, and documentation of pain scores. Several studies highlighted a discordance between pain scores, clinical judgment, and treatment decisions. Some tools had been used without being validated for postoperative pain or the age group studied. We found no studies of formal pain assessment methods used by parents. Observational subjectivity, the lack of current validity testing and standardization in methods, together with the multi‐faceted nature of pain reflects the need for a multidimensional approach to assess pain. Research is warranted on continuous monitoring of postoperative pain in infants and family involvement in pain assessment.

1. Background

Infants who undergo surgery in the first year of life represent a unique and vulnerable population. Their physiological and behavioral responses to pain are well‐known, and early exposure to repetitive pain increases the risk of long‐term neurodevelopmental, emotional, and behavioral consequences [1, 2]. In the absence of a gold standard, accurately assessing pain in this population remains a persistent clinical challenge [3].

In neonates and young infants, it is difficult to recognize and treat pain appropriately. Unlike older children or adults, these patients cannot self‐report their pain, requiring clinicians and caregivers to rely on indirect cues such as changes in facial expression, crying, physiological instability, or behavioral patterns [4]. For this review, a clinician is defined as a healthcare professional engaged in the clinical care of patients, specifically nurses and medical doctors. Over the past three decades, many tools have been developed to assess pain in infants. While many of these tools show adequate performance in the context of measuring acute procedural pain and for preterm infants [4, 5], there is limited evidence of their suitability for assessing immediate postoperative pain [6]. The physiological and behavioral responses to surgical recovery can differ significantly from those seen in routine care or procedural contexts [7].

While most research is focused on clinician‐administered assessment tools, parents may also detect subtle behavioral changes indicative of pain and discomfort in their baby [8]. The Position Statement of the Canadian Pediatric Society encourages active parental involvement in evaluating their child's pain, participating in decisions about pain management strategies, and taking the lead in implementing these interventions whenever feasible [9]. However, to assist in the effective management of pain, it is necessary to decode the infants' pain expressions [10]. A recent survey showed that pain assessment by parents is underutilized, as are parent‐targeted education programs on parent‐delivered interventions and interprofessional education programs, highlighting these as major areas for improvement [11]. Similarly, continuous or technology‐assisted monitoring and physiological biometrics for assessing postoperative pain remain an area of interest [12, 13, 14, 15] but are not well‐defined.

This scoping review aimed to map the current landscape of pain assessment tools used for infants aged 0–12 months following surgery. We focused on three core areas: pain assessment methods used by clinicians to assess postoperative pain in infants; pain assessment methods used by parents to assess postoperative pain in their infants aged 0–12 months; and the psychometric properties of tools used to assess pain including their validity, reliability, and clinical utility.

2. Methods

The review follows Preferred Reporting Items for Systematic reviews and Meta‐Analyzes extension for Scoping Reviews (PRISMA‐ScR) guidelines [16]. The methodology was guided by Arksey and O'Malley's [17] five‐stage framework as described below. The review protocol was registered prospectively in Open Science Framework in December 2023 [18], Registration https://doi.org/10.17605/OSF.IO/E5KCR.

2.1. Identifying the Initial Research Questions

Our review focused on the exploration of pain assessment methods utilized by clinicians and parents for the immediate postoperative pain assessment of infants. To ensure that the search captured a wide range of literature relating to this topic, we used the following initial research questions as a guide to the search process:

1. What are the pain assessment methods used by clinicians to assess postoperative pain in infants in healthcare settings?

2. What are the pain assessment methods available for parents to assess their infant's postoperative pain in healthcare settings?

3. What current psychometric properties (validity, reliability, and clinical utility) of the pain assessment methods most used by clinicians and parents in postoperative settings are being reported?

2.2. Identifying Relevant Articles

The search strategy aimed to identify studies that examined postoperative pain assessment methods in infants from 0 to 12 months of age. A comprehensive search strategy was derived by the research team and reviewed and adjusted in consultation with the university librarian. The strategy employed various combinations of the following terms: “infant,” “postoperative pain,” “pain assessment methods,” “parents,” “clinicians,” “hospitals.” The keywords and corresponding MESH terms were combined with the Boolean operators “AND” and “OR.” Six databases: Medline, Embase, Cochrane Central register of Controlled Trials, Cumulative index of nursing and allied health literature (CINAHL), PsychINFO and Scopus were searched. The final literature search was conducted on 15 March 2026, with a date restriction applied to include only studies published from 2014 onwards to ensure current relevance of studies. The complete search strategy is presented in Table S1. All retrieved studies were imported into Endnote [19] for the management of references and initial duplicates were removed. The remaining studies were imported into Covidence [20] for screening, data extraction and further removal of duplicates.

Title and abstract screening were performed by two independent reviewers (JJ and DW). Potentially relevant studies were retrieved in full text and assessed in detail against the inclusion criteria.

2.3. Study Selection

For the initial title and abstract screening, articles were included if the abstract was published in English and met one or more of the following criteria: included infants 0–12 months of age who were undergoing surgery, identified postoperative pain in the title or abstract, involved parents in infant pain assessment. For the full‐text screening, a further definition of “surgical procedure” was applied (a procedure involving the surgical opening of a body cavity). Articles were included only if the full text was available in English and the study reported on pain assessment methods used to assess postoperative pain in infants, aged 0–12 months, either exclusively or as a distinct subgroup within a broader pediatric population. Studies describing a parental role in infant pain assessment were also included.

Studies involving only procedural pain, preoperative or intraoperative pain or stress, studies involving children above 12 months of age or those focusing solely on pain management without pain assessment were excluded. Studies reporting on mixed populations of infants and older children were excluded if pain assessment methods specific to infants from 0 to 12 months of age were not reported separately. Incomplete studies, trial protocols, conference abstracts and animal studies were also excluded.

2.4. Data Extraction

A data extraction tool was developed and further refined in consultation with the research team. This tool was customized within Covidence and is presented in Table S2. Two reviewers (JJ and SL) independently reviewed the included studies, extracted the data, and cross‐checked the variables against each other. Any disagreements were resolved through discussions with a third reviewer (DW). The extracted data was exported from Covidence into Excel.

2.5. Critical Appraisal of Individual Sources of Evidence

As scoping reviews do not seek to assess the quality of evidence [17], no quality appraisal or risk of bias assessment was performed on the final included studies.

2.6. Synthesis of Results

Studies were summarized by study design, sample characteristics, type of surgery, pain assessment methods, duration of postoperative pain assessment, and psychometric properties of assessment methods. In the instance of systematic reviews, we included only the data from studies which met our inclusion criteria. Following Arksey and O'Malley [17], a narrative approach was used to synthesize the results.

3. Results

The search results are presented in full in the PRISMA‐ScR flow diagram (Figure 1). The literature search retrieved 734 articles. One study was subsequently identified through citation searching and was included [21]. After removing duplicates, 487 articles were screened for Title and Abstract. 366 articles were excluded, and 106 full‐text articles were assessed independently by two reviewers against the inclusion criteria. Thirty‐eight studies met the inclusion criteria. However, three systematic reviews were subsequently excluded because the reviews included studies published before 2014. A total of 35 studies were included for this scoping review (Tables 1 and 2).

FIGURE 1.

PRISMA diagram.

TABLE 1.

Included studies.

First author	Title	Study design	Study aims	Total participants	Sample characteristics	Surgery type (n)	Duration of pain assessment post‐operatively	Pain assessment tool/s used
Year							Frequency of assessment
Country
Bapat [22]	A multicenter collaborative to improve postoperative pain management in the NICU.	Multicentre, Quality Improvement (QI) initiative survey	To decrease unrelieved postoperative pain and improve family satisfaction with pain management.	23 Level IV NICUs	Multidisciplinary teams involved in post‐op care in NICU; Surveys: families; Pain scoring: NICU bedside nurses	NR	First 24 h post‐op	CRIES FLACC NPASS NIPS PIPP
2023							NR
United States of America (USA)
Barker [23]	Mapping pain assessment and management in a surgical neonatal intensive care unit: A process for best practice	Single‐centre, retrospective cohort study	To identify areas for practice improvement in the assessment and management of pain in neonates who had surgery and to determine the level of compliance with the current clinical practice guideline.	30	Birth GA, M = 36.2, Range = 25–41	Abdominal = 20 Thoracic = 8 Cardiac = 5	First 5 days post‐op	PAT
2014					BW (gms), M = 2570, Range = 726–4650		Required 12 scores over 24 h for first 24 h post‐op and a range of six to 30 over first 5 days post‐op depending on opioid duration
Australia
Benahmed‐Canat [24]	Postsurgery analgesic and sedative drug use in a French neonatal intensive care unit: A single‐center retrospective cohort study	Single‐centre, retrospective cohort study	To describe pain assessment, the pattern of analgesic and sedative drug use, and adverse drug reactions in a neonatal intensive care unit (NICU) during the postsurgery phase.	168	M:F = 100:68	Abdominal = 69 Inguinal hernia = 27 Thoracic = 20 Other = 43	First 7 days post‐op; Every 3 h or more frequently if needed	DAN EDIN
2019					Birth GA (weeks), M (SD) = 35.1 (4.6)
France					BW (gms), M (SD) = 2337 (1006.0)
					GA at surgery, M (SD) = 38.1 (3.3)
					Age at Surgery (days), Median (IQR) = 4 (0–142)
Cihlarova [25]	Rescue paracetamol in postoperative pain management in extremely low birth weight neonates following abdominal surgery: A single unit retrospective study	Single‐centre, retrospective cohort study,	To evaluate the unit protocol for postoperative pain management (≤ 48 h) to achieve postoperative analgesic efficacy goals (e.g., validated pain scores) after major abdominal surgery in ELBW infants	20	M:F = 9:11	Abdominal surgery = 20	First 48 h at least four times a day	COMFORTneo, ‘Obvious pain’ episodes reported
2022					Birth GA Median (IQR) = 24 + 5 (24 + 1 − 25 + 2)		At least four times per day (while infant resting)
Czech Republic					BW Median (IQR) = 667 (558–749)
					GA at surgery Median (IQR) = 27 (26 + 3 − 28 + 4)
Cinar [26]	Caudal ropivacaine and bupivacaine for postoperative analgesia in infants undergoing lower abdominal surgery	Single‐centre, RCT	To compare the postoperative analgesic efficacy of ropivacaine 0.175% and bupivacaine 0.175% injected caudally into infants for lower abdominal surgery.	80 Group 1 = 40 Group 2 = 40	M:F = 69/11	Circumcision = 29 Inguinal hernia = 19 Other = 26 (as reported in paper)	First 4 h postop	OPS, MAP, HR, SpO2 – continuous recording by monitor
2015					Age at surgery (months) M (SD) Gp1 = 7.5 (2.23) Gp 2, M (SD) = 7.05 (2.60) Median (IQR) Gp 1 = 8 (3–11) Gp 2 = 9 (3–12)		Hourly for first 4 h post‐op (starting in recovery room after extubation)
Turkey
Czarnecki [27]	Is there an alternative to continuous opioid infusion for neonatal pain control? A preliminary report of parent/nurse‐controlled analgesia in the neonatal intensive care unit	Single‐centre, retrospective cohort study	To evaluate the feasibility and efficacy of PNCA in postsurgical neonates and young infants and to compare outcomes of PNCA and COI.	33	M:F = 18:15	Abdominal = 28 Thoracic = 5	First 3 days post‐op	FLACC
2014					Birth GA Median (IQR) = 37 (24–42)		NR
USA					BW Median (IQR) = 2.9 (2–4.4)
					Age at surgery (days) Median (IQR) = 2 (1–21.5)
Dersch‐Mills [28]	Impact of dexmedetomidine in conjunction with a weaning protocol on post‐ surgical opioid use in a neonatal intensive care unit	Single‐centre, retrospective cohort study	To describe the impact of protocol‐driven dexmedetomidine (and clonidine) use on opioid exposure in post‐surgical neonates	104	M:F = 67:37	Abdominal = 57 Thoracic = 18 Other = 32	First 7 days post‐op	NPASS
2023					Birth GA, M (SD) Gp1 = 34.7 (4.8), Gp2 = 33.4 (4.9)		Every 2–4 h depending on duration of time post‐operatively and patient condition
Canada
Di Pede [29]	Comparison of regional vs systemic analgesia for post thoracotomy care in infants	Single‐centre, retrospective cohort study	To evaluate the safety and effectiveness of regional block, in the form of thoracic level epidural or extrapleural paravertebral analgesia, as compared to systemic analgesia for postoperative care in infants undergoing thoracotomy for congenital pulmonary malformations (CPM).	40	M:F = 22:18	Thoracic = 40	First 72 h post‐op	CRIES
2014					Birth GA Median (IQR) Gp1 = 39 (38–40) Gp 2 = 38 (37–39.5)		Every 4 h
Italy					Age at Surgery (days) Median (IQR) Gp1 = 89 (40–110), Gp2 = 90 (46–117)
Grabski [30]	A quality improvement intervention to reduce postoperative opiate use in neonates	Single‐centre, cohort study mixed retrospective and prospective	To reduce postoperative opioid use in neonates undergoing gastrointestinal surgery by 50% over a 2‐year time period	77	M:F = 35:42	Abdominal = 77	First 48 h post‐op	NPASS
2020					Birth GA, M (SD) Gp 1 = 33.3 (6.1), Gp2 = 34.03 (6.34)
USA					BW (gms), M (SD) Gp1 = 2.1 (1.19), Gp2 = 2.1 (1.35)		NR
					Age at surgery (days), Median (IQR) Gp1 = 15.5 (4.5–77.5); Gp2 = 14 (5–94)
Grabski [31]	Reduction of post‐operative opioid use in neonates following open congenital diaphragmatic hernia repairs: A quality improvement initiative	Single‐centre cohort study mixed retrospective and prospective	To reduce opioids in our NICU and evaluate the intervention in our CDH population.	45 Gp1 (pre‐intervention) = 18 Gp2 (peri‐intervention) = 6 Gp3 (post‐intervention) = 21	M:F = 19:5	Thoracic = 45	First 48 h post‐op	NPASS
2022					Birth GA Median (IQR) Gp1 = 38.9 (38–39.6) Gp2 = 38.7 (37–39.1) Gp3 = 38.2 (37.0–39.1)		NR
USA					BW Median (IQR) Gp1 = 2.9 (2.5–3.3), Gp2 = 2.6 (2.2–3.5), Gp3 = 3.2 (2.9–3.4)
					Age at surgery (days), Median (IQR) Gp1 = 10 (7–16), Gp2 = 5 (3–6), Gp3 = 6 (4–9)
Hausmann [32]	Automated deep learning approach for post‐operative neonatal pain detection and prediction through physiological signals	Single‐centre, prospective	To present a novel approach that combines continuous, non‐invasive monitoring of vital signs and Computer Vision/Deep Learning to make automatic neonate pain detection and prediction of the time to onset of post‐surgical pain in neonates.	N = videos ranging in length from 2 to 21+ h obtained from 75+ post‐surgical neonates monitored for post‐operative pain.	NR	NR	Videos ranging in length from 2 to 21+ h	HR, RR, SR (oxygen saturation), converting visual information into integers stored as an array data structure. NPASS
2025							Continuous monitoring
USA
Ilhan [33]	Trajectories of post‐surgical pain in infants admitted to neonatal intensive care	Single‐centre retrospective cohort study	(a) to statistically identify distinct trajectories of pain following surgery in infants less than 6 months of age, and (b) to compare these trajectories to descriptions of chronic pain in infants in the neonatal intensive care unit.	726	M:F = 390:336	Thoracic = 444 Abdominal = 282	Until 24 h of no analgesia	PAT
2020					Birth GA Mean = 36 (4.4)		on return to ward from theater, 2 hourly for first 24 h post‐op, then 4 hourly
Australia					BW (gms) Mean = 2700 (941.2)
					Age at surgery (days) M = 11.2 (17.5)
Ismail [34]	Laparoscopic vs. open pyloromyotomy in treatment of infantile hypertrophic pyloric stenosis	Single‐centre RCT	To compare outcomes for laparoscopic and classic open approach techniques in the management of pyloric stenosis.	80		Abdominal = 80	NR	Pain Assessment in Neonates (PAIN) Scale
2020							Started at 1 h post‐op, frequency NR
Egypt
Kendigelen [35]	Transversus abdominis plane block for postoperative analgesia in neonates and young infants: Retrospective analysis of a case series	Single‐centre Case series retrospective	To analyze retrospectively the analgesic effectiveness of TAP block in neonates and infants undergoing abdominal and inguinal surgeries.	34	Birth GA, Median (IQR) = 43 (39–47)	Abdominal = 34	First 24 h postoperative	CRIES
					Age at surgery (days), M (SD) = 36.2 (24.2), Min‐Max = 2–88
2017					Post‐conceptual age at surgery (weeks), Median (IQR) = 43 (39–47)		NR
Turkey
Meesters [36]	Infants operated on for necrotizing enterocolitis: Towards evidence‐based pain guidelines	Single‐centre, retrospective cohort study	To describe pain management in neonates before and after NEC‐related surgery and to determine if their pain assessment scores were comparable to those of patients admitted to the NICU with other diagnoses.	60	M:F = 24:36	Abdominal = 60	First 72 h post‐op	COMFORTneo sNumerical Rating Scale (NRS)
2016					Birth GA, Median (IQR) = 28+3 (25 + 5 − 31 + 6)		while resting at least once during every 8‐h shift. Extra assessment was indicated after the administration of sedatives or analgesics and if pain or over‐/undersedation was suspected
Netherlands					BW, Median (IQR) = 1053 (836–1525)
					Age at surgery (days), Median (IQR) = 10 (8–22)
Nanayakkara [37]	Efficiency of post‐operative pain management in infants undergoing cleft lip and palate repairs: A study using the FLACC Scale	Single‐centre cohort study	To assess the effectiveness of the local analgesic protocol during the first 24 h after cleft surgeries.	193 Gp1 = 80 Gp2 = 113	Age at surgery (months) M (SD's not reported) Gp1 = 4.4 Gp2 = 9.2	Cleft palate = 193	First 24 h post‐op	FLACC
2021							5 min after recovery from GA, then every 30 min up to 4 h, then hourly at 5 and 6 h post‐recovery, then at 8 am and 12 noon the first post‐op day
Sri Lanka
Olischar [38]	The addition of tramadol to the standard of IV acetaminophen and morphine infusion for postoperative analgesia in neonates offers no clinical benefit: a randomized placebo‐controlled trial	Single‐centre RCT	to determine whether tramadol's addition to standard analgesic care for postsurgical neonates reduced time to extubation, postoperative pain, opioid, or sedative requirements compared with standard analgesic care without tramadol. to assess the impact of the addition of tramadol on amplitude‐integrated electroencephalography (aEEG).	71 Gp1 = 36 Gp2 = 35	M:F = 35:36	Abdominal = 35 Thoracic = 34 Other major thoraco‐abdominal = 2	First 5 days post‐op	PAT, BP, HR, SpO2. Continous ECG & aEEG recordings
2014					Birth GA (n) 32–36 weeks = 17 36+ weeks = 54		Hourly
Australia					BW (gms), M (SD) Gp1 = 2825 (584) GP2 = 2894 (768)
Paul [39]	Comparing opioid with opioid‐free anesthesia technique in neonates undergoing tracheoesophageal fistula repair	Single‐centre, prospective blind randomized trial	To assess and compare the on‐table extubation rate, extubation time, and postoperative pain scores between opioid and opioid‐free anesthesia techniques in neonates undergoing surgical repair of TEF.	60 Gp1 = 30 Gp2 = 30	M:F = 25:35	Thoracic = 60	Up to 6 h post op or when NIPS score = 4	NIPS
2023					Age at surg (days), M (SD) Gp1 = 2.5 (1.9), Gp2 = 2.0 (1.1)		At 15 min, 30 min, 45 min, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 4 h, 5 h, 6 h and for a total of 6 h after extubation or until the NIPS score was four
India
Pehlajani [40]	Postoperative pain management in neonatal surgery: Evaluating the role of multimodal analgesia	Single‐centre, prospective observational study	to evaluate the role of multimodal analgesia in neonatal surgery at a tertiary care center to determine the safety and efficacy of this approach in neonatal postoperative care.	120	GA M (SD) = 35.4 (2.5)	Abdominal = 45 Thoracic = 30 Urological = 45	NR	NIPS PIPP (for prem)
2025
India
Popat [41]	Continuous local anesthetic wound infusion of bupivacaine for postoperative analgesia in neonates: a randomized control trial (CANWIN Study)	Single‐centre, RCT	To determine the effect of continuous wound infusion of local anesthetic (bupivacaine) on total amount of systemic opioid use in the first 72 h in newborn infants undergoing laparotomy.	30 Gp1 = 16 Gp2 = 14	M:F = 19:11	Abdominal = 30	First 72 h postop	PAT
2022					Birth GA, Median (IQR) Gp1 = 38 (38–39), Gp2 = 38 (37–39)		Every 2 h for first 24 h, every 4 h for next 48 h & every 2 h after a change in analgesia dose. Scoring continued until opioids ceased for 8 h
Australia					BW, Median (IQR) Gp1 = 3250 (2965–3570), Gp2 = 3133 (2820–3601)
					Age at surgery (days), Median (IQR) Gp 1 = 2.5 (2–4.5) Gp2 = 4 (2–6)
Prestes [42]	Painful procedures and analgesia in the NICU: What has changed in the medical perception and practice in a 10‐yr period?	Multicentre cohort study, 3 prospective cohorts of neonates & survey of neonatologists 1st–31st October in 2001, 2006, 2011	To compare the use of analgesia versus neonatologists’ perception regarding analgesic use in potentially painful procedures performed in critically ill newborns in three different times over a ten‐year period.	188 physicians	All neonates admitted to 4 university NICUs in children's hospitals	NR	First 3 days post‐op	VAS NFCS NIPS
2016					M:F, (% neonates) 2001 = 50:41, (75%) 2006 = 67:47, (51%) 2011 = 65:60, (50%)		NR
Brazil					BW (gms), M (SD) 2001 = 1889 (879) 2006 = 2058 (977) 2011 = 1915 (909)
Puthoff [43]	Development of a structured regional analgesia program for postoperative pain management	Single‐centre mixed retrospective and prospective cohort study, QI initiative	To minimize the use of postoperative opioids by increasing the use of postoperative regional analgesia as standard care for eligible surgical procedures in the NICU from 0% to 80% by June 30, 2019	55	M:F = 31:24	Scheduled thoracic & abdominal surgery (further details NR)	First 48 h postop	NPASS
2021					Birth GA, Median (IQR) Gp1 = 35 (28.7–37.6) Gp2 = 34.86 (26.5–37)		NR
USA					BW, Median (IQR) Gp1 = 2.23 (0.98–2.72) Gp2 = 2.09 (0.96–2.80)
					GA at surgery, Median (IQR) Gp1 = 38.29 (34.9–41.6) Gp2 = 42.6 (38.7–45)
Relland [44]	Continuous epidural chloroprocaine after abdominal surgery is associated with lower postoperative opioid exposure in NICU infants	Single‐centre, matched retrospective cohort study	To evaluate associations between use of continuous epidural chloroprocaine and improved intra‐ and post‐operative outcomes, including post‐operative opioid use.	48	M:F = 27:21	Abdominal = 48	First 5 days post‐op	NPASS FLACC BP
2022					Birth GA, M (95% CI) Gp1 = 33.3 (30.0–36.6), Gp2 = 33.6 (95% CI 30.4–36.8)		NR
USA					BW (kgms), M (95% CI) Gp1 = 2.3 (1.7–2.9) Gp2 = 2.2 (1.5–2.9)
					Age at surgery (weeks), M (95% CI) Gp1 = 10.8 (6.9–14.7), Gp2 = 8.5 (4.3–12.7)
Saleh [45]	Role of dexamethasone in the para‐vertebral block for pediatric patients undergoing aortic coarctation repair. Randomized, double‐blinded controlled study	Single‐centre RCT	To compare ultrasound‐guided paravertebral block using bupivacaine alone and bupivacaine with dexamethasone in terms of the intra‐ and postoperative analgesic requirements and hemodynamics, postoperative complications and ICU stay duration in children undergoing surgery for aortic coarctation.	50	M:F = 24:26	Cardiac = 50	First 24 h post‐op	OPS (Objective Pain Score)
2018					Age at surgery (months), M (SD) Gp1 = 8.2 (2.27) Gp2 = 8.3 (2.16)		Immediately post‐op, then at 4 h, 8 h, 12 h & 24 h post‐op
Egypt
Salekin [46]	Multimodal spatio‐temporal deep learning approach for neonatal postoperative pain assessment	Single‐centre cohort study	To compare the performance of a novel multimodal spatio‐temporal approach that integrates visual and vocal signals and unimodal neonatal postoperative pain assessment, and measure the impact of temporal information integration.	9	M:F = 5:4 Further sample details not reported	NR	First 3 h post‐op	NPASS Plus–multimodal approach combining facial expression, body movement, and crying.
2021a							NR
USA
Salekin [47]	Multimodal neonatal procedural and postoperative pain assessment dataset	Single‐centre cohort study	To introduce a publicly available multimodal neonatal pain assessment dataset that can be used to develop artificial intelligence systems that monitor, assess, and predict neonatal pain based on the analysis of behavioral and physiological responses.	9 infants post‐surgery	M:F = 3:5 (missing = 1)	Gastroschisis, Omphalocele repair, Inguinal hernia repair	First 3 h after completion of surgery	NPASS Plus‐ HR, BP, SpO2
2021b					Birth GA, M = 35.32 Preterm (< 37 weeks), n = 5		Every 15 min
USA					BW (gms) M = 2733.33 Low (< 2500 g), n = 4 (SD's not reported)
Sprecher [48]	A NICU postoperative pain management improvement project to reduce uncontrolled pain and improve staff satisfaction	Single‐centre, QI project	To improve postoperative pain control for infants in our neonatal intensive care unit (NICU), limit variability in the approach to pain management, and increase staff satisfaction.	811	NR	Abdominal, N not reported	First 24 h post‐op	PIPP‐R FLACC NPASS
2025							Minimum of every 4 h assessments with requirements for reassessment within 1 h following elevated scores or after an intervention.
USA
Staals [49]	Efficacy and safety of wound catheter infusion with ropivacaine after abdominal surgery in children aged < 1 year: A randomized controlled trial	Single‐centre prospective RCT	To investigate the efficacy and safety of WCI with ropivacaine as treatment for postoperative pain in infants aged < 1 year after abdominal surgery.	30 Gp1 = 15 Gp2 = 15	M:F = 20:10	Abdominal = 30	First 24 h post‐op	COMFORT‐B, Numeric Rating Scale (NRS)
2025					GA, Median (Range) Gp1 = 37.6 (34.4–40.2) Gp2 = 38.0 (36.5–39.5)		Every 2 hourly for first 24 h, followed by regular basis. Also, ten minutes after each extra dose of morphine, pain was reassessed.
Netherlands					BW, Median (IQR) Gp1 = 3.0 (2.5–3.4) Gp2 = 3.0 (2.4–3.4)
					Age at surg (days), Median (IQR) Gp1 = 105 (60–174) Gp2 = 111 (66–147)
Valkenburg [50]	Pharmacodynamics and pharmacokinetics of morphine after cardiac surgery in children with and without Down Syndrome	Single‐centre cohort study	To compare the pharmacodynamics and pharmacokinetics of IV morphine after cardiac surgery in two groups of children‐ those with and without Down syndrome.	38 Gp1 = 21 Gp2 = 17	M:F = 15:25	Cardiac = 38	Until switch from IV to oral morphine/discharge to ward/required GA & reintubation	COMFORT‐B NRS
2016					Birth GA, Median (IQR) Gp1 = 39 (37–40), Gp2 = 40 (39–41)		at least 2nd hourly
Ireland					Age at surgery (days), Median (IQR) Gp1 = 175 (127–272) Gp2 = 155 (118–233)
Vavolizza [51]	Standing intravenous acetaminophen is associated with a reduction of post‐operative opioid use in infants aged less than 1 year treated on the acute care floor	Single‐centre QI Study Retrospective chart review: Pre‐intervention (Jan 2012 – Jan 2016) Prospective cohorts: Roll‐out (Jan 2016–Dec 2016), post‐intervention (Dec 2016–Dec 2020)	To study the effect of using standing IV acetaminophen for postsurgical infants aged less than 1 year recovering on the acute care floor. To reduce post‐operative opiate use by at least 50% over a 2‐y time period.	131 Gp1 = 56 Gp2 = 17 Gp3 = 58	M:F = 70: 67	Abdominal = 131 s	First 48 h postop	FLACC
2022					Birth GA, M (SD) Gp1 = 36.6 (3.8) Gp2 = 38.1 (3.7) Gp3 = 37.3 (2.5)		NR
USA					BW (kg), M (SD) Gp1 = 2.6 (1.0) Gp2 = 3.0 (0.9) Gp3 = 2.8 (0.7)
					Age at surgery (days) Gp1 M = 183 (102) Gp2 M = 174 (106) Gp3 M = 156 (89)
Zeilmaker‐Roest [52]	Intermittent intravenous paracetamol versus continuous morphine in infants undergoing cardiothoracic surgery: a multi‑center randomized controlled trial	Multi‐centre RCT	To determine whether intermittent intravenous paracetamol as primary analgesic would significantly reduce morphine consumption in children aged 0–3 years after cardiac surgery with cardiopulmonary bypass.	194 Gp1 = 94 Gp2 = 100	M:F = 103: 91	Cardiac = 194	First 48 h post‐op	COMFORT‐B Numeric Rating Scale‐11 (NRS‐11) pain
2024					Age at surgery (months), Median (IQR) Gp1 = 5 (3–10), Gp2 = 4 (2–7)		every 2 h
Belgium and Netherlands

Abbreviations: BP, Blood pressure; BW, Birth weight; CI, confidence interval; COMFORT‐B, COMFORT Behavioral Scale; COMFORTneo, COMFORT Neonatal Scale; CRIES, Crying, Requires O₂ for saturation < 95%, Increased vital signs, Expression, Sleeplessness; DAN, Douleur Aiguë du Nouveau‐né; EDIN, Échelle Douleur Inconfort Nouveau‐Né; FLACC, Face, Legs, Activity, Cry, Consolability; GA, Gestational age; gms, grams; Gp, group; HR, Heart rate; IQR, Interquartile range; M, Mean; M:F, male:female; MAP, Mean Arterial pressures; MDTs, Multidisciplinary teams; NFCS, Neonatal Facial Coding System; NICU, Neonatal Intensive Care Unit; NIPE, Newborn Infant Parasympathetic Evaluation; NIPS, Neonatal Infant Pain Scale; NPASS, Neonatal Pain, Agitation and Sedation Scale; NR, Not reported; NRS, Numerical Rating Scale; OPR, Objective pain report; OPS, Objective Pain Score; PAIN, Pain Assessment in Neonates Scale; PAT, Pain Assessment Tool; PIPP, Premature Infant Pain Profile; QI, Quality improvement; RCT, randomized controlled trial; SD, standard deviation; SpO2, Oxygen saturation; VAS, Visual Analogue Scale.

TABLE 2.

Included systematic reviews.

First author	Title	Type of review	Inclusion criteria dates	Eligible studies for inclusion in current review/Total reviewed	Pain assessment tools used
Year
Country
Llerena [3] 2023 USA	Neonatal pain assessment: Do we have the right tools?	Systematic review	2016–2021	2/14	NPASS
					NIPS
					PAT
Olsson [53] 2021 Sweden	The use and reporting of neonatal pain scales: A systematic review of randomized trials	Systematic review of RTs	Inception to March 2019	5/352	CHEOPS
					EDIN
					NPASS
					PAT
					PIPP/PIPP‐R
Popowicz [54] 2020 Poland	Pain scales in neonates receiving mechanical ventilation in neonatal intensive care units—systematic review	Systematic review	2006–2019	4/12	NPASS
					NIPS
					PIPP
Sakthivel [21] 2024 Australia	Newborn and Infant Parasympathetic evaluation (NIPE) monitor for assessing pain during surgery and interventional procedures: A systematic review	Systematic review	2010–2023	2/10	HRV derived NIPA
					FLACC
					COMFORT‐B

Abbreviations: CHEOPS, Children's Hospital of Eastern Ontario Pain Scale; COMFORT‐B, COMFORT Behavioral Scale; EDIN, Échelle Douleur Inconfort Nouveau‐Né; FLACC, Face, Legs, Activity, Cry, Consolability; HRV, Heart rate variability; NIPE, Newborn Infant Parasympathetic Evaluation; NIPS, Neonatal Infant Pain Scale; NPASS, Neonatal Pain, Agitation and Sedation Scale; PAT, Pain Assessment Tool; PIPP‐ R, Premature Infant Pain Profile‐ revised; PIPP, Premature Infant Pain Profile; USA, United States of America.

3.1. Study Characteristics

As shown in Figure 2, most studies were conducted in the USA (12, 32%), followed by Australia (5, 14%). Three studies were conducted in the Netherlands, including one study in collaboration with Belgium. Egypt, India, and Turkey each conducted two studies. Each of the following countries conducted one study: Brazil, Canada, France, Ireland, Italy, Poland, Sri Lanka, and Sweden. The final total included 8 randomized controlled trials [26, 34, 38, 39, 41, 45, 49, 52], eight prospective cohort studies [22, 37, 40, 42, 46, 47, 48, 50], 10 retrospective studies [23, 24, 25, 27, 28, 29, 33, 35, 36, 44], and five of mixed retrospective and prospective designs [30, 31, 32, 43, 51]. Three systematic reviews [3, 53, 54] were included, with one review added later [21]. Most studies were single‐centre (28, 80%), followed by multicentre studies (3, 9%) and systematic reviews (4, 11%) (Tables 1 and 2).

FIGURE 2.

Number of included studies per country.

3.2. Pain Assessment Methods Used by Clinicians

Studies included in the scoping review used 20 different pain assessment methods (Tables 1, 2 and S3). These included clinical observation using pain assessment tools, physiological monitoring (heart rate, blood pressure, oxygen saturation), a device for objective continuous monitoring of physiological measures such as the Newborn Infants Parasympathetic Evaluation (NIPE) monitor and automated deep learning technologies for pain detection. Some studies reported multiple pain assessment measures [22, 24, 25, 32, 36, 40, 42, 44, 49, 50, 52]. The Neonatal—Pain, Agitation and Sedation Scale (NPASS) was used in 13 of the 35 studies, making it the most used tool among studies included in this review. Other assessment tools (in order of use) were the Face, Legs, Activity, Cry and Consolability (FLACC) scale, the Pain Assessment Tool (PAT), and the Neonatal Infant Pain Scale (NIPS). These tools were only used for assessment by clinicians.

Predominantly, postoperative pain was not identified as a distinct category. Instead, postoperative pain was variously categorized as acute [3, 21, 24, 53, 54], prolonged [21, 24, 28, 54], continuous [3], chronic [3, 54] or ongoing [28, 33, 34] pain, with some authors not specifying a pain category at all [3]. Popowicz et al. [54], further described how postoperative pain can be classified as both acute and chronic, or assessed as “acute prolonged pain.” Some authors noted that it is difficult to apply the traditional definition of chronic pain within a neonatal context [3, 54], while others suggested that pain continued despite treatment and recommended continuous monitoring for postoperative pain [33].

Where reported, the duration and frequency of pain assessment as an outcome measure varied across studies. The duration of postoperative pain assessment ranged from 3 h [46] to the seventh postoperative day [24, 28], but was mostly conducted for the first 48 h post operation [25, 30, 31, 43, 51, 52]. The frequency of assessment varied from every 30 min for the first 6 h after recovery [37], or at least once during an eight‐hour shift [36]. Most studies reported hourly [26, 52] or second hourly assessments [49], at least for the first 4 h following surgery [23, 28, 33, 35].

Several studies reported poor compliance with assessment and documentation of pain scores [23, 24, 25, 28]. Compliance appeared to depend on clinicians' subjective judgment, particularly when pain scores were low [23] or the baby appeared in no obvious distress [24, 25]. In one study with multiple missing scores on the first postoperative day, the authors hypothesized that perhaps nurses saw little value in documenting a score of zero for babies who were likely still anesthetized [24]. The same study also found that by the seventh postoperative day, 46% of infants had no pain scores recorded. The authors concluded that the low scores and poor compliance reflected either that the babies were over‐sedated or that the assessment tools [the Échelle Douleur Inconfort Nouveau‐Né (EDIN) and Douleur Aigue du Nouveau‐ne (DAN)] were not appropriate for assessing postoperative pain in infants [24]. Another study [22] evaluating the adoption of evidence‐based interventions across 23 neonatal units found that neonatologists' compliance with pain assessment documentation over a three‐year period increased from 53% to only 66% [22]. Across all studies, pain scores were inconsistently reported in clinical practice, despite individual unit guidelines and policies.

3.3. Pain Assessment Methods Used by Parents

We found no studies of pain assessment methods either used by parents or reported for parental use. The few studies that considered families in this review focused on family satisfaction with pain management strategies [22]. One study showed improved family satisfaction with pain management using a protocol where pain scores were reviewed with the family two or more times within the first 24 postoperative hours; however, the scores were based on clinician (not parental) assessment [22]. In their study of neonates following abdominal surgery, Cihlarova et al. [25], recommended greater parental contribution to pain assessment. In two studies, parents of neonates who had undergone major surgery had refused study interventions [49] or attachment of additional probes or sensors, which presented a challenge to using objective pain assessment methods [46].

3.4. Psychometric Properties of Pain Assessment Methods

Most studies cited publications describing the original development of pain assessment tools [22, 23, 39, 46, 47, 48, 49, 53]. The psychometric properties of the most used tools (NPASS, FLACC, PAT, NIPS) were predominantly reported in studies conducted prior to 2014, or on samples or settings outside of our inclusion criteria [53, 54]. In their review, Olsson et al. [53], noted that many of the validation studies of pain assessment tools were conducted before the introduction of guidelines such as Consensus‐based Standards for the selection of Health Measurement Instruments (COSMIN). In addition to the commonly used pain assessment methods (shown in Table 1), two studies reported on locally developed non‐validated tools [25, 53].

The authors of the systematic reviews included in this scoping review (Table 2) noted that assessment tools had been used in studies without being validated for postoperative pain and/or the age group studied [3, 53, 54]. Our findings support these concerns (Table 3). Although there is no “gold standard” pain assessment tool, some studies validated tools against each other [54], despite the comparator not being validated for the type of pain or the study population. The review by Llerena et al. [3], found that studies comparing different tools generally reported poor correlation between scores. Another study compared areas under the curve for the FLACC and COMFORT‐B to assess NIPE as a measure of early postoperative pain and found that NIPE could detect pain and discomfort, but there was no evidence of predictive value [57].

TABLE 3.

Clinical applicability of pain assessment tools used in the included studies—Validity for population of interest by gestational age, age group, and type of pain.

Name of tool	Used in included studies (Reference ID)	Validity*
		Neonates		Infants	Type of pain*
		Preterm (GA: ≤ 36 weeks)	Term (GA:37–40 weeks)	Infants (up to 12 months)	Post‐operative pain
CHEOPS	[53]	X	√b	√	√
COMFORT‐B	[21, 49, 50, 52]	√ (≥ 35)	√	√	X
COMFORTneo	[25, 36]	√ (≥ 24)	√	X	X
CRIES	[22, 29, 35]	√ (≥ 32)	√	X	√
DAN	[24]	√	√	X	X
EDIN	[24, 53]	√ (25–36)	√b	X	X
FLACC	[21, 22, 27, 37, 44, 48, 51]	X	√	√	√
NFCS	[42]	√ (≥ 29)	√	√	√b
NIPE	[21]	I	I	I	I
NIPS	[3, 22, 39, 40, 42, 54]	√	√	√ (≤ 7 months)	X
NPASS	[3, 22, 28, 30, 31, 32, 43, 44, 46, 47, 48, 53, 54]	√ (≥ 23)	√	X	√b
NRSa	[36, 49, 50, 52]	NR	NR	NR	NR
OPS	[26, 40, 45]	√ (≥ 32)	√	√	√
PAIN Scale	[34]	√ (≥ 26)	√	X	X
PAT	[3, 23, 33, 38, 41, 53]	√	√	X	√
PIPP	[22, 40, 53, 54]	√	√	X	X
PIPP‐R	[53]	√	√	X	X
VAS	[42]	√ (≥ 35)	√	√	√

Note: √: validated for use in populations of this GA, age group, and type of pain; √^b: predominantly validated for use in this age group and pain type, although conflicting evidence exists; X: not validated for use in this type of population or pain; I: Inconclusive; NR: evidence not reported. ^aNone of the studies using NRS cited a reference for the NRS, except 27 which cited a reference for the NRS‐11 validated for self‐report use with verbal children. Italic values represents the reference number for the study that included the tool.

Abbreviations: CHEOPS, Children's Hospital of Eastern Ontario Pain Scale; COMFORT‐B, COMFORT Behavioral Scale; COMFORTneo, COMFORT neonatal scale; CRIES, Crying, Requires O₂ for saturation < 95%, Increased vital signs, Expression, Sleeplessness; DAN, Douleur Aiguë du Nouveau‐né; EDIN, Échelle Douleur Inconfort Nouveau‐Né; FLACC, Face, Legs, Activity, Cry, Consolability; NFCS, Neonatal Facial Coding System; NIPE, Newborn Infant Parasympathetic Evaluation; NIPS, Neonatal Infant Pain Scale; NPASS, Neonatal Pain, Agitation and Sedation Scale; NRS, Numerical Rating Scale; OPS, Objective Pain Score; PAIN, Pain Assessment in Neonates Scale; PAT, Pain Assessment Tool; PIPP, Premature Infant Pain Profile; PIPP‐R, Premature Infant Pain Profile‐revised; VAS, Visual Analogue Scale.

^*Information sourced from (reference ID): Giordano et al. [4]; Arabiat et al. [5]; Olsson et al. [53]; Popowicz et al. [54]; Färnqvist et al. [55]; Smith et al. [56]. Contradictory results noted in Table.

The subjectivity of pain assessment tools was highlighted by many of the studies included in this scoping review, with concerns about the potential for interobserver variability [39]. In a survey of neonatologists, context was found to affect scoring. Clinicians were more likely to assign less pain in infants who had undergone minor rather than major surgery [42]. In their quality improvement studies, Grabski et al. [30, 31], concluded that nurses had likely underreported NPASS pain scores because they were aware of the aim to reduce opioid use. Only one study mentioned that nurses were blinded to the study intervention, thus reducing potential bias [45]. DiPede et al. suggested that nurses' interpretations of infants' behavior were affected by parents' presence [29].

Reliability was inconsistently addressed across the 32 studies. The one study that reported inter‐rater reliability showed good agreement on FLACC scores (Kappa 0.85 and Pearson's coefficient 0.89), but this was measured between two research nurses trained for the study [47]. The authors of another study acknowledged that when using PAT, there is a risk of underestimating pain because of the limited behavioral repertoire of young infants [33]. Other authors warned of incorrect low scores due to blank facial expressions and lack of body movement in critically ill newborns with necrotising enterocolitis [36]. Similar concerns could apply to infants in the immediate postoperative period because of the effect of anesthetic, sedation, or muscle relaxants.

Some authors noted challenges to ease of use (Table 3), some of which can impact reliability. Several studies highlighted a discordance between pain scores, clinical judgment, and treatment decisions. Most of the original studies in this scoping review evaluated the effectiveness of pain management strategies without reporting pain assessment results. Instead, other clinical outcomes such as the need for mechanical ventilation [29], reduced respiratory support [38], reduced opioid use [28, 43], or improved feeding outcomes [29] were reported as proxy measures (Figure 3). Other parameters used as pain assessment measures included heart rate (HR) [45, 47], oxygen saturation (SpO₂) [47], blood pressure (BP) [45, 47], and heart rate variability (HRV) [21]. Some authors noted that physiological measures such as HR did not correlate well with pain scores [26, 29, 45]. Dipede et al. suggested that while increased HR can be a proxy for pain, it could also be explained by an immature sympathetic nervous system in this age group [29]. In studies where an intervention was used, the outcome was often that both study groups reported equivalent pain scores [27, 29, 30, 31, 38, 39, 41, 43, 44, 50, 51, 52]. Often, these other parameters were given more weight in treatment decisions than pain scores [29, 30, 31].

FIGURE 3.

Clinical outcomes as proxy measures of postoperative pain. BP, Blood pressure; HR, Heart rate; SpO2, oxygen saturation.

Thresholds for the clinical management of pain varied across studies, even when using the same tool [24]. In two studies using the NPASS, one group defined scores above four [22] as indicative of pain, while the other group defined scores above three as the pain threshold [28]. Thresholds also varied for CRIES, with some authors recommending intervention for scores above five [29] and others for scores above four [22, 35]. Many authors acknowledged the challenges in distinguishing pain from other sources of distress or discomfort in infants, noting that several factors can confound the accurate interpretation of pain scores [27]. In the absence of clear consensus on how to interpret certain scales such as the EDIN and DAN, clinicians frequently set their own threshold for intervention [24]. This inconsistency was also evident in cases where medication was administered, even when the COMFORTneo scores were below the recommended treatment threshold [25]. Nurses appeared to rely more on the visual discomfort of infants to report obvious pain, even when pain tool scores were low [25].

4. Discussion

This scoping review included 35 studies comprising 31 original studies and four systematic reviews. The review identified varying approaches to pain assessment by clinicians, poor pain documentation and a lack of reporting of the psychometric properties (validity, reliability, and clinical utility) of the tools used to assess postoperative pain in infants 0–12 months of age. The review also highlights the lack of published studies reporting on parents' involvement in pain assessment.

Twenty different pain assessment methods were identified among the papers included in this review, and all were used exclusively by clinicians. This degree of variation in pain assessment methods concurs with the findings of other reviews [58]. Tools were often used in settings and with samples that were inconsistent with the contexts in which the psychometric properties were originally tested [59]. Even for the NPASS, the most commonly used tool across all studies, there is inconclusive evidence about performance across the diversity of postoperative infants [3, 4, 6]. Further, inconsistency in the definition of postoperative pain made it challenging to identify tools used specifically for this type of pain.

Our results align with those of a recent review [55] and include a notable finding that clinical decisions about pain management are rarely correlated with documented pain scores. Even where pain was a primary outcome measure, pain assessment scores were inconsistently used to guide pain management. This could be due to multiple factors but included the variation of intervention thresholds across studies that used identical scales. There was also significant variation in the duration and frequency of postoperative pain assessment, which may limit the clinical utility of pain assessment tools. Equivalent pain scores between comparison groups were often interpreted as showing no superior benefits of the intervention. The frequent finding of missing pain scores also reflects a gap in clinical practice indicating the need for continuous monitoring in the postoperative period. Our findings suggest that even where pain scores were collected, treatment decisions were based on other outcomes such as opioid use or ventilation requirement. This is a new finding from our review of the literature.

Additionally, the clinical utility of pain assessment methods to guide patient management is questionable when they continue to be based on subjective assessment. Professional experience and emotions have been shown to influence clinicians' pain scoring [60]. Diendl et al. [60], found that clinicians assigned higher pain scores to stimuli they considered “noxious” rather than just distressing, and when they had a full body view rather than face and hands only. They suggested that clinicians become conditioned through witnessing repeated painful procedures over time [60]. The reliable performance of pain assessment tools, including the NPASS, is reported to be highly dependent on adequate training [3, 54]. Effective training, however, can be resource‐intensive, limiting the feasibility of a tool for clinical use [3, 54, 61].

Concern about the subjective nature of clinical rating scales is ongoing. After reviewing evidence regarding psychometric properties, two recent reviews concluded that no observer‐administered pain tool can be considered as a “gold standard” for pain assessment in infants [5, 55].

Emerging research around continuous pain monitoring has explored automated facial recognition, movement sensors, or physiological biometrics such as HRV [12, 21]. Evidence to date has been inconclusive due to variations in methodology, the lack of a gold standard tool for comparison, and difficulty obtaining parental consent in critical care settings [3, 41, 53]. Reports over the years have also highlighted the discordance between behavioral, physiological, and cortical measures [3, 12].

One of the most striking and disappointing findings of this review was the lack of inclusion and underutilized role of parents in postoperative pain assessment in infants. Despite family‐centered care (FCC) practices in most pediatric clinical settings around the world, the role of parents in assessing pain in their infant was notably absent. A recent international survey reported that NICUs rarely incorporate parents in their pain assessment guidelines, and where included, parents were infrequently asked about their assessment of their infants' pain [11]. This could be due to a lack of information resources, lack of practices to support parents, misunderstanding of the philosophy of FCC, a staff‐parent communication gap, or barriers related to the infant's postoperative condition [62].

Parents are potentially valuable observers of their infant's normal and abnormal behaviors, yet they are mostly excluded from the pain assessment process. To effectively contribute to pain assessment, parents require knowledge around identifying pain signals, particularly the parents of newborns [63]. While there is a body of literature on educating parents about pain signals [64], this information does not relate specifically to postoperative infants. There is a need to adopt more inclusive family‐centered models of care for pain management.

5. Clinical Implications

We believe this to be the first scoping review of pain assessment methods used by clinicians and parents to assess postoperative pain in infants up to 12 months of age. Given the variability in pain expression in infants during the postoperative period and the definition of an “infant,” the reliance on episodic, subjective assessments may be insufficient for optimal opioid titration and analgesic care. Our findings strongly support the call for objective continuous monitoring of pain in postoperative infants and for the greater involvement of parents in the assessment process. This could better inform timely and effective pain management. The findings of this review may guide clinicians in selecting the most appropriate pain assessment tool tailored to the individual child and their parents.

6. Limitations of the Included Studies

Most of the studies included in this review were retrospective, with the time lag between data collection and publication ranging from 3 to 8 years [23, 24, 25]. This limitation has implications for clinical currency and study quality.

Lack of compliance with pain assessment policies and poor documentation was widely noted, even in the prospective studies included in this review. Although limiting the study findings, this scoping review does offer further insight into the clinical utility of pain assessment tools. Findings were also limited by a lack of current information regarding the psychometric performance of tools in the study samples and relevance to specific age groups, with several authors raising concerns about potential bias related to the subjectivity of pain assessment tools and the lack of definition of age groups.

7. Limitations of the Review

This scoping review included a wide age range (0–12 months) which was based on the heterogeneous evidence in the literature. Our results, however, provide information that may be used to select pain assessment methods appropriate for individual infants. The review excluded studies published before 2014 to avoid confounding the psychometric performance of pain assessment tools in the context of significant changes to the clinical care of infants in the past decade. Generalizability is limited because only studies published in English were included. However, our sample included studies from a wide variety of countries (Figure 2). A key limitation of this review was that, despite our aim and extensive searching, no studies were identified that related to parents' direct assessment of pain in infants undergoing surgical procedures at birth to 12 months of age.

8. Conclusion

This review highlights significant inconsistency in pain assessment methods for postoperative infants 0–12 months of age. Observational subjectivity, the lack of currency of validity testing, difficulty extracting the results of specific age groups, the absence of standardization in the duration and frequency of assessment, as well as the role of competing information in clinical decision‐making, reflect the multi‐faceted nature of pain and the need for a multidimensional assessment approach. Involving family in infant pain assessment has the potential to improve pain care, reduce burden on clinicians, and empower families. Further research exploring continuous pain assessment methods during the postoperative period is needed. Evidence from well‐designed research could promote consistency and greater family involvement in practices leading to better postoperative pain care for this vulnerable, non‐verbal population.

Funding

This work was supported by Cerebral Palsy Alliance Research Foundation (Grant PHD03423).

Conflicts of Interest

We would like to disclose a potential conflicts of interest regarding two of the co‐authors of this manuscript. The study conducted by Himanshu Popat et al. [41], has been included in the scoping review, which may create a perceived conflict of interest due to the involvement of author Himanshu Popat and co‐author Jeewan Jyoti.

To ensure transparency and maintain the integrity of our work, we have sought input and verification from independent researchers, Donna Waters and Sharon Laing, to ensure the objectivity of the analysis and interpretation.

The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supporting information

Table S1: Complete search strategy.

Table S2: Data extraction tool customized within covidence.

Table S3: List of abbreviations of pain assessment methods.

Data Availability Statement

The data that supports the findings of this study are available in the Supporting Information of this article.