Overview
Definition:
The heel stick is a common neonatal procedure used to obtain capillary blood samples for diagnostic testing
It involves puncturing the lateral or medial plantar surface of the heel
Effective pain control is crucial to minimize distress and physiological stress responses in the newborn.
Epidemiology:
Almost all newborns in Neonatal Intensive Care Units (NICUs) and many in well-baby nurseries undergo repeated heel sticks for routine screening (e.g., metabolic screening, blood gas analysis, bilirubin levels) and monitoring
The frequency can range from a few times to over 20 times in critically ill infants.
Clinical Significance:
Proper heel stick technique minimizes tissue damage and risk of infection
Adequate pain management during this procedure is vital for infant well-being, reducing stress hormones, promoting feeding, and preventing long-term behavioral changes
It is a fundamental skill for pediatric residents preparing for DNB and NEET SS examinations.
Heel Stick Technique
Patient Selection:
Choose the lateral or medial plantar surface of the heel, avoiding the posterior curvature
Do not puncture deeper than 2.4 mm
The medial aspect should be avoided if the infant has a history of phlebitis or has undergone surgery in this area
Avoid areas that are edematous, infected, or have a previous puncture site.
Equipment Preparation:
Gather sterile supplies: sterile gloves, antiseptic wipe (e.g., alcohol or chlorhexidine), sterile gauze pads, appropriate lancet (depth-controlled, typically 2.4 mm for term infants, 1.0-1.5 mm for preterm infants), collection tubes or microvettes
Warming the heel can improve blood flow.
Procedure Steps:
Clean and dry the heel site
Warm the heel with a dry towel or commercial warmer for 3-5 minutes
Perform a quick, firm puncture with the sterile lancet perpendicular to the heel
Wipe away the first drop of blood with sterile gauze to remove any residual antiseptic or tissue fluid
Gently collect subsequent drops into the collection device
Apply gentle pressure with sterile gauze to stop bleeding
Do not "milk" the heel excessively, as this can lead to hemolysis and inaccurate results
Cover the puncture site with a sterile bandage or gauze, ensuring it is not too tight.
Post Procedure Care:
Monitor the puncture site for bleeding or signs of infection
Ensure proper disposal of all sharps and contaminated materials
Document the procedure, including site, time, and any pain management used.
Pain Assessment In Newborns
Pain Indicators:
Facial grimacing
Furrowed brow
Crying (high-pitched)
Body movements (stiffening, arching)
Changes in heart rate, respiratory rate, blood pressure, and oxygen saturation
Neonatal Infant Pain Scale (NIPS) and Premature Infant Pain Profile (PIPP) are validated tools.
Physiological Signs:
Tachycardia
Hypertension
Tachypnea or apnea
Decreased oxygen saturation
Increased intracranial pressure
Stress hormone elevation (cortisol, catecholamines).
Behavioral Cues:
Vocalizations (crying, whimpering)
Facial expressions (brow bulge, eye squeeze, nasolabial furrow)
Body posture (fisted hands, extended extremities, arching)
Sleep-wake state changes (difficulty settling, irritability).
Pain Control Strategies
Pharmacological Interventions:
Topical anesthetics: EMLA cream (lidocaine 2.5%/prilocaine 2.5%) applied 60-90 minutes prior to procedure
Oral sucrose: 24% solution given 2 minutes before procedure, 0.5-2 mL dose, provides central analgesia via opioid receptors
Acetaminophen: For sustained pain relief, typically 15 mg/kg orally or rectally every 4-6 hours.
Non Pharmacological Interventions:
Swaddling: Provides containment and security
Pacifier: Non-nutritive sucking can be comforting and reduce pain
Breastfeeding or glucose nipple: Oral stimulation and comfort
Kangaroo care (skin-to-skin contact): Promotes bonding and reduces infant stress
Environmental modification: Dim lights, reduce noise
Comfort positioning: Gentle support.
Combination Approaches:
Utilizing a multimodal approach combining pharmacological agents (e.g., topical anesthetic or oral sucrose) with non-pharmacological methods (e.g., swaddling, pacifier use) often yields the best pain relief
For more invasive or prolonged procedures, parenteral analgesia (e.g., fentanyl, midazolam) may be considered under close monitoring, but is generally not required for routine heel sticks.
Age And Gestational Considerations
Preterm Infants:
Have thinner skin and a less developed nervous system, making them more vulnerable to pain
Require shallower lancets (1.0-1.5 mm)
Pain management is critical
sucrose and non-pharmacological methods are highly recommended
Increased risk of complications like ROP and IVH from pain and stress.
Term Infants:
Can tolerate slightly deeper punctures (up to 2.4 mm)
Respond well to sucrose, pacifiers, and swaddling
Pain management remains important to minimize distress and promote positive feeding behaviors.
Post Term Infants:
May have tougher skin, potentially requiring careful site selection and a slightly firmer pressure for adequate blood flow
Standard pain management techniques apply.
Complications And Prevention
Potential Complications:
Infection at the puncture site
Hematoma formation
Excessive bleeding
Nerve damage (rare, associated with improper site selection or technique)
Necrosis (especially with superficial or repeated punctures)
Hemolysis of blood sample.
Prevention Strategies:
Strict aseptic technique
Correct lancet depth selection for gestational age
Proper site selection (lateral/medial plantar aspect, avoiding bone and nerves)
Adequate warming of the heel
Avoid excessive milking
Gentle pressure post-procedure
Using topical anesthetics or sucrose to blunt the pain response
Rotating puncture sites.
Key Points
Exam Focus:
DNB/NEET SS examiners will assess understanding of appropriate lancet depth, site selection to avoid nerves and bone, and the evidence-based use of pain relief modalities like oral sucrose and topical anesthetics
Knowledge of pain assessment tools (NIPS, PIPP) is also important.
Clinical Pearls:
Always warm the heel
it significantly improves blood flow and reduces the need for repeated punctures
Wipe away the first drop of blood
Do not "milk" the heel aggressively
Multimodal analgesia is key
Document all pain interventions.
Common Mistakes:
Using a lancet that is too deep
Puncturing too close to the posterior curvature of the heel
Not using any pain relief
Excessive milking of the heel leading to hemolysis
Not performing aseptic technique
Failure to properly document the procedure and interventions.