Assessment of Pain in Newborns and Older Infants (Infant Pain Assessment Study =


Pain assessments in non-verbal, critically ill infants represent an important clinical challenge. Older children or adults can easily express their pain, but infants lack that capability. They frequently experience repetitive acute pain during routine ICU care, but their analgesic management flounders on the horns of a dilemma: (a) failure to treat infant pain leads to immediate clinical instability and potentially long-term physical, behavioral, and cognitive sequelae, vs. (b) strong analgesics may increase risks for medical complications and/or impaired brain growth. Bedside nurses currently assess pain using pain scores, before taking action to ameliorate pain. Pain scores increase nursing workload and provide subjective assessments, rather than objective data for evaluating infant pain. Consequently, infants exposed to skin-breaking procedures, surgery, or other painful conditions often receive variable and inconsistent pain management in the ICU. The investigators aim to develop a multimodal pain assessment system, using sensor fusion and novel machine learning algorithms to provide an objective measure of pain that is context-dependent and rater-independent. This will enhance the quality of pain management in ICUs and allow continuous pain monitoring in real-time.

Full Title of Study: “Using Machine-learning Algorithms to Assess Acute Pain in Nonverbal Infants”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: November 2025


  • Other: Pain Measurement
    • Measurement of infant responses (behavioral and physiological) during a painful procedure.

Arms, Groups and Cohorts

  • Preterm infants
    • preterm neonates (34-37 weeks gestational age, n=15)
  • Term infants
    • term newborns (37-42 weeks gestation, n=15)
  • Small infants
    • 1-3 month-old infants (n=15)
  • Older infants
    • 3-6 month-old infants (n=15)

Clinical Trial Outcome Measures

Primary Measures

  • Pain Measurement (all infants)
    • Time Frame: 10 minutes
    • Visual Analogue Scale (VAS) measures pain intensity based on observer assessment on a scale from 1 to 10, where higher values indicate more intense pain.

Secondary Measures

  • Pain Measurement
    • Time Frame: 30 minutes
    • Facial Expressions specific for infant pain will be assessed, including nasolabial furrow and brow bulge. Presence or absence as well as the duration for each facial expression will be recorded during the painful procedure. These facial expressions were chosen from the Neonatal Facial Coding Scale (NFCS) and the Premature Infant Pain Profile (PIPP).
  • Pain Measurement (newborns 0-30 days)
    • Time Frame: 5 minutes
    • Neonatal Pain, Agitation and Sedation Scale (N-PASS) measures level of sedation versus increasing pain or agitation in newborns. Scores range from -10 to +10, where negative scores denote increasing levels of sedation, zero indicates a neutral condition, and positive scores indicate increasing pain intensity and/or agitation.
  • Pain Measurement (newborns 0-30 days)
    • Time Frame: 8 minutes
    • Premature Infant Pain Profile – Revised (PIPP-R) measures pain intensity in newborns, with scores ranging from 0 to 21, higher scores indicating greater pain (adjusted for prematurity and behavioral state).
  • Pain Measurement (infants 1-6 months)
    • Time Frame: 3 minutes
    • Face, Legs, Activity, Cry, Consolability scale (FLACC scale) measures pain in children between the ages of 2 months and 7 years. The scale is scored in a range of 0-10 with 0 representing no pain and 10 indicating severe pain.

Participating in This Clinical Trial

Inclusion Criteria

  • 1. All infants less than 6 months of corrected chronological age. 2. Infants admitted to the participating ICUs at LPCH (NICU, PICU, CVICU). 3. Require an acute painful procedure for routine clinical care. Exclusion Criteria:

1. Newborns with birth trauma, intrapartum asphyxia (5-minute Apgar Score <4 or cord pH < 7.01), fetal growth restriction (birth weight < 5th percentile for gestation), congenital anomalies or metabolic disorders, or any kind of brain injury. 2. Newborns born to mothers with a history of heavy smoking or drug abuse (alcohol, cocaine, ketamine, heroin/other opiates) or psychiatric drugs used during this pregnancy. 3. Newborns and infants requiring positive pressure ventilation using a face mask (BiPAP) or endotracheal tube (conventional or high-frequency ventilators). 4. Newborns and infants receiving continuous infusions of opioid drugs (morphine, fentanyl, others) and nerve blocks or neuraxial analgesia affecting the site of the invasive procedure during the 24 hours prior to study entry. (Note: Infants receiving intermittent opioids or non-opioid analgesics (acetaminophen, ibuprofen, ketorolac, others) WILL NOT be excluded). 5. Newborns and infants with facial anomalies, injuries or other pathologies affecting the facial area.

Gender Eligibility: All

Minimum Age: N/A

Maximum Age: 6 Months

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Stanford University
  • Collaborator
    • Autonomous Healthcare, Inc.
  • Provider of Information About this Clinical Study
    • Principal Investigator: Kanwaljeet Anand, Professor of Pediatrics, Anesthesiology, Perioperative & Pain Medicine – Stanford University
  • Overall Official(s)
    • Kanwaljeet S Anand, MBBS, D.Phil., Principal Investigator, Prof.

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