What are the guidelines for managing hyperbilirubinemia in newborns using the Bhutani chart?

Management of Neonatal Hyperbilirubinemia Using the Bhutani Chart

The Bhutani nomogram is the gold standard tool for risk-stratifying newborns ≥35 weeks gestation by plotting hour-specific bilirubin values against postnatal age to determine follow-up timing and phototherapy decisions. 1

Understanding the Bhutani Nomogram

The nomogram divides infants into four distinct risk zones based on predischarge total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) measurements plotted against the infant's exact age in hours (not days): 2, 1

• High-risk zone (≥95th percentile): Requires immediate intervention and close follow-up 2
• High-intermediate risk zone (75th-94th percentile): Follow-up within 24-48 hours 1
• Low-intermediate risk zone (40th-74th percentile): Follow-up within 48-72 hours 1
• Low-risk zone (<40th percentile): Routine follow-up is sufficient 1

Patient Population for Bhutani Chart Application

The nomogram applies specifically to: 1

• Infants ≥36 weeks gestational age with birth weight ≥2000g, OR
• Infants ≥35 weeks gestational age with birth weight ≥2500g

Critical caveat: The Bhutani nomogram should NOT be used for preterm infants <35 weeks gestation, who require different management thresholds. 3

When to Measure Bilirubin

Obtain TSB or TcB measurement immediately if: 1, 4

• Jaundice appears within the first 24 hours of life
• Jaundice appears excessive for the infant's age
• Any doubt exists about the degree of jaundice

Never rely on visual assessment alone, as this leads to significant errors, particularly in darkly pigmented infants. 2, 1

Critical Measurement Requirements

All bilirubin levels must be plotted using the infant's age in hours, never in days. 1 This is a common and dangerous error that can lead to inappropriate risk stratification. 1

Major Risk Factors Requiring Heightened Surveillance

Identify these high-risk features that increase the likelihood of severe hyperbilirubinemia: 2

• Predischarge bilirubin in the high-risk zone on the nomogram
• Jaundice observed in the first 24 hours
• Blood group incompatibility with positive Coombs test or other hemolytic disease (especially G6PD deficiency, which causes 31.5% of kernicterus cases) 5
• Gestational age 35-36 weeks
• Previous sibling who received phototherapy
• Cephalohematoma or significant bruising
• Exclusive breastfeeding with poor nursing and excessive weight loss
• East Asian race

Follow-Up Timing Based on Discharge Age

The American Academy of Pediatrics provides specific follow-up schedules based on discharge timing: 2

Infant Discharged	Must Be Seen By
Before 24 hours	72 hours
Between 24-47.9 hours	96 hours
Between 48-72 hours	120 hours

Infants discharged before 48 hours may require two follow-up visits: first between 24-72 hours, second between 72-120 hours. 2

Earlier or more frequent follow-up is mandatory for infants with risk factors, while those with few or no risk factors can be seen at longer intervals. 2

Laboratory Workup for Elevated or Rising Bilirubin

When bilirubin is rising rapidly (>0.2 mg/dL/hour after 24 hours) or unexplained by clinical assessment, obtain: 4, 5

• Blood type and Coombs test
• Complete blood count with peripheral smear
• Direct or conjugated bilirubin
• Reticulocyte count (optional but helpful)
• G6PD testing when TSB approaches exchange levels, fails to respond to phototherapy, or severe hyperbilirubinemia occurs in at-risk ethnic groups (11-13% of African Americans, higher in Mediterranean and Asian populations) 1

Treatment Thresholds Using the Nomogram

The AAP provides separate nomograms for phototherapy initiation based on: 2, 6

• Gestational age at birth
• Presence of neurotoxicity risk factors
• Hour-specific bilirubin levels

Phototherapy should be initiated when TSB reaches or exceeds the phototherapy threshold for the infant's age and risk category. 4 The 2022 AAP guidelines use higher thresholds than previous recommendations. 7

Monitoring Phototherapy Effectiveness

Once phototherapy is initiated: 4

• Clinical impact should be evident within 4-6 hours
• Expect a decrease of >2 mg/dL in serum bilirubin concentration
• Measure TSB to verify efficacy after starting treatment
• If TSB continues to rise despite intensive phototherapy, hemolysis is very likely occurring 2

Common Pitfalls to Avoid

Never use days instead of hours when plotting values on the nomogram—this is a critical error. 1

Never discharge infants with jaundice in the first 24 hours without measuring bilirubin levels. 1

Never fail to ensure appropriate follow-up in the presence of elevated risk factors; delay discharge if necessary until follow-up can be ensured or the period of greatest risk (72-96 hours) has passed. 2

Never fail to test for G6PD deficiency in high-risk ethnic groups with severe hyperbilirubinemia, as this accounts for nearly one-third of kernicterus cases. 1, 5

Parent Education at Discharge

All hospitals must provide written and verbal information including: 2

• Explanation of jaundice
• Need to monitor infants for jaundice
• Specific advice on how monitoring should be performed
• When to seek immediate medical attention

Alternative Predictive Models

Recent research suggests that models incorporating the difference between predischarge TSB and the phototherapy threshold (Δ-TSB) may have superior discrimination (AUC 0.93-0.95) compared to the Bhutani nomogram alone (AUC 0.88) and may be simpler to use. 6 However, the Bhutani nomogram remains the AAP-recommended standard for clinical practice. 1