What is the Pediatric Early Warning Score (PEWS), how is it calculated from vital signs, and what monitoring or escalation actions correspond to score ranges of 0‑2, 3‑4, and ≥5?

Pediatric Early Warning Score (PEWS): Definition, Calculation, and Response Protocol

PEWS is a numeric scoring system that assigns points to abnormal vital signs and clinical observations across multiple domains (respiratory, cardiovascular, behavioral/neurological) to identify hospitalized children at risk for clinical deterioration, though its effectiveness in reducing mortality remains unproven. 1

What PEWS Measures

PEWS systems evaluate pediatric patients by scoring deviations from age-appropriate normal ranges in several clinical domains 1:

• Respiratory parameters (respiratory rate, work of breathing, oxygen requirements)
• Cardiovascular parameters (heart rate, capillary refill, blood pressure)
• Behavioral/neurological status (level of consciousness, activity)

The critical distinction is that PEWS uses age-dependent physiological thresholds that reflect normal pediatric vital sign ranges, which differ substantially from adult values 2. This is why adult scoring systems like NEWS2 cannot be adapted for children 2.

Score Calculation and Interpretation

While multiple PEWS variants exist, most follow a similar structure 3, 4:

• Each clinical domain receives points based on severity of abnormality (typically 0-3 points per domain)
• Total scores typically range from 0-9 or higher depending on the specific PEWS tool used
• Higher scores indicate greater physiological instability and risk of deterioration 5

The Brighton PEWS (BPEWS) is the most commonly adopted tool internationally and can identify clinical worsening approximately 11 hours before cardiac arrest 4.

Age-Specific Application

Patients < 13 years of age must be assessed with PEWS exclusively 2. For adolescents aged 13-17 years, PEWS should be used preferentially, though clinicians may use adult criteria at their discretion 2. Do not attempt to "adjust" adult scoring systems for pediatric use—the thresholds are fundamentally incompatible with pediatric physiology 2.

Response Actions by Score Range

While specific thresholds vary by institution and PEWS variant, a general escalation framework exists 6:

Low-Risk Scores (typically 0-2)

• Continue routine monitoring at standard intervals 6
• Document score with each vital sign assessment 7
• No immediate escalation required 6

Moderate-Risk Scores (typically 3-4)

• Increase monitoring frequency (often to hourly assessments) 6
• Notify primary team for bedside evaluation 6
• Implement early interventions (oxygen, fluid bolus, medication adjustments) as clinically indicated 6
• Consider consultation with senior clinician 6

High-Risk Scores (typically ≥5)

• Activate rapid response team (RRT) or medical emergency team (MET) for immediate bedside evaluation 6
• Continuous monitoring until patient stabilizes 6
• Prepare for potential PICU transfer 5, 6
• Senior physician assessment required 6

Evidence for Clinical Effectiveness

The evidence supporting PEWS remains limited but shows some promise:

• One observational study demonstrated PEWS discriminated between children requiring PICU transfer versus those who did not (area under curve = 0.89) 5
• PEWS implementation in hospitals with established MET systems was associated with reduction in cardiac arrest rates from 0.15 to 0.12 events per 1000 patient-days 1, 2
• However, there is no evidence that PEWS reduces overall hospital mortality 1

The 2015 American Heart Association guidelines state that "the use of PEWS may be considered, but its effectiveness in the in-hospital setting is not well established" (Class IIb, Level of Evidence C-LD) 1.

Implementation Considerations and Pitfalls

PEWS should not be used in isolation—it functions best as part of a comprehensive rapid response system with clear escalation protocols 3, 6. Key implementation factors include:

• Integration into electronic medical records improves uptake and accuracy of scoring (achieving >89% accuracy in implementation studies) 7
• Staff education and feedback mechanisms are essential for maintaining scoring accuracy and appropriate responses 7, 6
• PEWS reduces unnecessary RRT activations (from 33% to 3.5% in one quality improvement study) while maintaining patient safety 6
• The tool improves nursing-physician communication and clinical autonomy at the bedside 6

Common pitfall: Relying solely on PEWS without clinical judgment. The score should supplement, not replace, clinical assessment and concern 3. If a clinician is worried about a patient, escalate care regardless of the PEWS value 6.

Current Limitations

The confidence in PEWS effectiveness remains low because 1:

• Most evidence comes from before-and-after observational studies with significant risk of confounding variables
• The low baseline rate of pediatric cardiac arrests makes demonstrating statistically significant mortality benefit difficult
• No standardized PEWS tool exists—multiple variants are in use with different scoring thresholds 3, 4
• Optimal cutoff values for intervention vary by institution and patient population 3