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Updated: Mar 6, 2026

A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
EDIN Scale Implemented by Gestational Age for Pain Assessment in Preterms: A Prospective Study
G Raffaeli1, G Cristofori1, B Befani1
1NICU, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
Insights
A modified pain scale (EDIN6) improved chronic pain detection in premature infants. This new scale, incorporating postmenstrual age (PMA), significantly enhanced pain assessment accuracy for preterm neonates.
Area of Science:
- Neonatal care
- Pain assessment in neonates
- Pediatric neurology
Background:
- Chronic neonatal pain can negatively impact immature brain development.
- The existing EDIN scale may not be optimal for assessing prolonged pain in premature infants.
- Postmenstrual age (PMA) is a crucial factor in neonatal pain perception.
Purpose of the Study:
- To evaluate a modified EDIN scale (EDIN6) that includes postmenstrual age (PMA) as a sixth item.
- To compare the effectiveness of the EDIN6 scale against the standard EDIN scale in assessing pain in neonates.
- To determine if EDIN6 improves pain detection accuracy, particularly in premature infants.
Main Methods:
- A two-phase prospective study involving pain assessments in neonates admitted to a NICU.
- Phase T1 used the standard EDIN scale; Phase T2 utilized the EDIN6 scale with PMA-based scoring.
- Nursing staff completed questionnaires to assess the perceived adequacy of both EDIN and EDIN6 scales.
Main Results:
- A total of 15,960 pain assessments were recorded across both phases.
- The EDIN6 scale nearly tripled the cumulative detection of pain compared to the EDIN scale (117/7267 vs. 52/8693, p=0.001).
- Significant improvements in pain detection were observed in less mature infant groups (PMA 25-32 and 33-37 weeks), with perceived adequacy by nurses increasing from 13.4% to 71.4% for lower PMA infants.
Conclusions:
- The EDIN6 scale demonstrates potential for enhanced pain evaluation in preterm infants.
- Incorporating postmenstrual age into pain assessment scales improves detection accuracy for vulnerable neonates.
- The EDIN6 scale offers a more sensitive tool for identifying prolonged pain in premature infants.
Abstract:
Background. Chronic neonatal pain can lead to long-term adverse effects on the immature brain. EDIN scale for prolonged pain might not be fully suitable for premature infants. We aimed to test a modified EDIN scale, adding postmenstrual age (PMA) as a sixth item (EDIN6). Methods. In a two-phase prospective study, pain was assessed in all neonates admitted in our NICU. In T1 EDIN was applied; in T2 EDIN6 with additional scores of 2, 1, and 0, respectively, for 25-32, 33-37, and >37 weeks PCA was tested. Scores > 6 suggested pain. The nursing staff was given a questionnaire to evaluate EDIN and EDIN6. Results. A total of 15960 pain assessments were recorded (8693 in T1; 7267 in T2). With EDIN6, cumulative detection of pain almost tripled (117/7267 versus 52/8693, p = 0.001). Main differences were found among less mature categories (50/1472 versus 17/1734, p = 0.001 in PCA 25-32; 26/2606 versus 10/4335, p = 0.001 in PMA 33-37; 41/3189 versus 25/2624, p = 0.26 in PMA > 37). Adequacy of pain assessment in lower PMA was judged "medium-high" in 13,4% of nurses in T1 and 71,4% in T2. Conclusions. EDIN6 may allow improved evaluation of pain in preterm infants.

