The Premature Infant Pain Profile-Revised (PIPP-R): Initial Validation and Clinical Feasibility

Introduction and Rationale

Pain management in Neonatal Intensive Care Units (NICUs) is critical, particularly for premature infants who undergo numerous painful procedures with little recovery time. Unmanaged pain has both immediate negative consequences (like altered hemodynamic stability) and long-term effects (such as changes in pain reactivity and neuronal structures). Accurate pain assessment is the essential first step toward effective management.

The widely used Premature Infant Pain Profile (PIPP), a 7-item composite measure, was a valuable tool, but it lacked sufficient validation in the most vulnerable population: Extremely Low Gestational Age (ELGA) infants (born before 28 weeks). A key issue was that the original PIPP could produce a falsely elevated pain score for ELGA infants based solely on their static contextual factors—specifically, their Gestational Age (GA) and Baseline Behavioural State (BS)—even if they showed no physiological or behavioral response to a painful event.

The PIPP-R was developed to address these validity and feasibility concerns for all GA groups, especially ELGA infants, by revising how these indicators were scored.

Methodology: Validating the Revisions

The researchers retained the original seven indicators (Heart Rate, Oxygen Saturation, Brow Bulge, Eye Squeeze, Naso-Labial Furrow, GA, and BS) but altered the scoring methodology to reflect the core revision:

The Critical PIPP-R Change: Contextual variables (GA and BS) are now only scored if there is an observable change in the physiological or behavioral variables (i.e., if the Sub-total Score for these 5 items is greater than 0). If the infant shows no response to the painful stimulus, the final pain score is 0, regardless of prematurity or sleep state.

To validate these revisions, a secondary analysis was conducted using data from two existing randomized cross-over studies:

Dataset #1 (ELGA Validation): Compared PIPP and PIPP-R scores in 52 ELGA infants following a nonpainful event (diaper change) versus a painful event (heel lance).
Dataset #2 (Intervention Effectiveness): Compared PIPP and PIPP-R scores in 85 infants (25 to 41 weeks GA) to assess the effectiveness of three different pain-relieving interventions (sucrose alone, sucrose + non-nutritive sucking [NNS], and facilitated tucking + NNS + sucrose) during a heel lance.

Additionally, a survey was conducted among 31 NICU nurses to determine the PIPP-R’s clinical feasibility (ease of use, clarity of scoring, and time required).

Key Results and Findings

The validation established both the construct validity and feasibility of the PIPP-R:

Construct Validity

Discrimination (Dataset #1): PIPP-R scores successfully differentiated between painful and nonpainful events in ELGA infants. Scores were significantly lower during nonpainful procedures (mean 8.3) compared to painful procedures (mean 9.9).
Accuracy: In 21% of ELGA infants in Dataset #1, the original PIPP produced a higher score than the PIPP-R because the PIPP-R correctly assigned a score of 0 when the infant showed no physiological or behavioral response.
Responsiveness to Intervention (Dataset #2): The PIPP-R scores were sensitive to the effectiveness of pain relief. Scores were significantly lowest when infants received the combined intervention of NNS + sucrose, suggesting the measure accurately tracks intervention efficacy.

Clinical Feasibility

Positive Feedback: Overall, nurses rated the PIPP-R as highly feasible (median score of 4 out of 5), reporting that it was easy to use and score.
Preference for Revisions: Nurses specifically liked the inclusion of Gestational Age and Behavioral State as modifying variables rather than baseline components, confirming the practical relevance of the core revision.

Conclusion and Clinical Implications

The initial study successfully demonstrated the construct validity and feasibility of the Premature Infant Pain Profile-Revised.

The most important finding is that the PIPP-R is a more accurate reflection of an infant's pain response because it eliminates the risk of a falsely elevated score based on static factors when no actual response to pain is observed. This standardized and conditional scoring approach makes the interpretation of pain response more meaningful across the full spectrum of gestational ages.

While the PIPP-R is a strong tool, the authors recommend further testing with broader groups of infants and pain conditions, as well as exploring its relationship with emerging indicators of pain, such as cortical responses measured by EEG or near-infrared spectroscopy.

Reference: Stevens, B. J., Gibbins, S., Yamada, J., Dionne, K., Lee, G., Johnston, C., & Taddio, A. (2014). The Premature Infant Pain Profile-Revised (PIPP-R): Initial Validation and Feasibility. The Clinical Journal of Pain, 30(3), 238–243.