# The Influence of Postmenstrual Age and Neurological Impairments on the Modified Pain Assessment Tool Score in Infants Admitted to Neonatal Intensive Care: A Retrospective Medical Record Review

## TL;DR

This study found that the modified Pain Assessment Tool (mPAT) can be used for infants in NICUs regardless of their age or neurological impairments, though younger infants showed higher behavioral pain responses.

## Contribution

The study provides evidence that the mPAT is suitable for assessing pain in infants regardless of postmenstrual age or neurological impairment.

## Key findings

- Neither postmenstrual age nor neurological impairment predicted total mPAT or physiological pain scores.
- Extremely-to-very preterm infants showed 3.7 times higher behavioral pain scores compared to term infants.
- The mPAT is suitable for use in NICUs regardless of infant age or neurological status.

## Abstract

Repetitive and prolonged experience of pain by infants in neonatal intensive care units (NICUs) may adversely affect growth and alter pain responses. The degree of infant prematurity and/or presence of neurological impairment (NI) may impact an infant's ability to behaviorally respond to pain. This study aimed to determine whether the scores on the mPAT, a widely used pain assessment tool, is impacted by postmenstrual age (PMA) at assessment, irrespective of neurological impairment. Data from medical records were collected on infants admitted to the NICU who underwent a pain assessment with the modified Pain Assessment Tool (mPAT) between March 2019 and September 2021. Total mPAT, behavioral, and physiological pain scores were independently analyzed using logistic regression to detect differences based on PMA categories (< 33 weeks, 33–36 weeks, ≥ 37 weeks) and presence of NI. Significant differences were indicated when p < 0.05. Of 204 infants sampled, 62% were male, and 71% were born at term‐age (i.e., ≥ 37 wks). Thirty‐six (18%) infants had a queried or confirmed NI and 28 (14%) infants were postsurgical. Logistic regression analysis showed that neither PMA nor presence of NI predicted pain for total mPAT scores (χ
2 (3) = 3.9, p > 0.05) or physiological scores (χ
2 (3) = 2.7, p > 0.05). Higher behavioral scores were 3.7 times (OR 0.27, 95% CI 0.10–0.77, p = 0.01) more likely in extremely‐to‐very preterm (< 33 weeks) infants when compared to term (≥ 37 weeks) infants. The mPAT may be suitable for clinicians to utilize when assessing infants in NICUs regardless of PMA or NI status. The higher behavioral responses in younger infants require further investigation in a future prospective study.