What is normal capillary refill time in infants?

Normal Capillary Refill Time in Infants

Normal capillary refill time in healthy infants is less than 3 seconds, with values greater than 2 seconds potentially indicating compromised peripheral perfusion. 1

Definition and Normal Values

Capillary refill time (CRT) is a clinical assessment tool used to evaluate peripheral perfusion and circulatory status in infants. The measurement involves:

• Applying moderate pressure to blanch the skin
• Releasing the pressure
• Measuring the time taken for normal color to return

Normal Range by Age and Location:

• In infants older than 7 days:
  • Finger: ≤2 seconds is considered normal 2
  • Chest or foot: ≤4 seconds is considered normal 2
  • Values >3 seconds generally warrant clinical concern 1

Proper Measurement Technique

To obtain reliable CRT measurements in infants:

• Apply moderate pressure for 5 seconds 2
• Use the finger as the preferred measurement site 2
• Maintain ambient temperature between 20°C-25°C 2
• Consider using a stopwatch to reduce inter-observer variability 2
• Ensure adequate lighting to visualize color return

Factors Affecting CRT Measurements

Several factors can influence CRT values in infants:

• Temperature: Lower ambient or skin temperature prolongs CRT 3
• Birth weight: Low birth weight babies tend to have shorter CRT values 4
• Measurement site: Values vary between hand, foot, and chest 3
• Duration of pressure: Longer pressing times result in longer CRT 5
• Environmental factors: Phototherapy and radiant warmers shorten CRT 4

Clinical Significance

CRT is particularly valuable in assessing circulatory status in critically ill infants:

• In septic shock, CRT >2 seconds indicates cold shock 1
• Prolonged CRT (>3 seconds) with hypotension indicates severe hemodynamic compromise with higher mortality risk 1
• CRT should be interpreted alongside other clinical signs:
  • Mental status
  • Heart rate
  • Blood pressure
  • Urine output
  • Peripheral pulses

Limitations and Pitfalls

Important caveats when using CRT in clinical practice:

• CRT alone has limited reliability in the first few hours after birth 5
• Inter-observer variability is significant, even among experienced clinicians 3
• CRT should not be used in isolation but as part of a comprehensive hemodynamic assessment 4
• The relationship between CRT and cardiovascular status is not always straightforward in neonates 5
• Sequential measurements show a trend toward decreasing values (order effect) 3

Clinical Application

When assessing an infant with suspected circulatory compromise:

1. Measure CRT on the finger using standardized technique
2. Values >2 seconds warrant closer monitoring
3. Values >3 seconds indicate potential shock requiring intervention
4. Use CRT as part of goal-directed therapy to restore normal perfusion
5. Target CRT <3 seconds during resuscitation efforts 1

In emergency settings, reversal of prolonged CRT using appropriate resuscitation measures has been associated with a 40% reduction in mortality odds ratio 1.