ASSESSMENT OF HUMAN FETUSES UNDERGOING ACUTE PAIN: VALIDATION OF THE FETAL-7 SCALE.

Improvements in fetal ultrasound have allowed for the diagnosis and treatment of fetal diseases in the uterus, often though surgery. However, little attention has been drawn to the assessment of fetal pain. To address this gap, a fetal pain scoring system, known as the Fetal-7 scale, was developed. The present study is a full validation of the Fetal-7 scale. The validation involved two steps: i. four fetuses with indication of surgery were evaluated in three conditions perioperatively: acute pain, rest, and under loud sound stimulation. Facial expressions were assessed by 30 raters using screenshots from 4D high-definition ultrasound films; ii., assessment of sensitivity and specificity of the Fetal-7 scale in 54 healthy fetuses and two fetuses undergoing acute pain after preoperative anesthetic intramuscular injection. There was high internal consistency with Cronbach's alpha (α) of 0.99. Intra-rater reliability of the Fetal-7 scale (test-retest) calculated by intraclass correlation coefficient (ICC) was 0.95, and inter-rater reliability was 0.99. The scale accurately differentiated between healthy fetuses at rest and those experiencing acute pain (sensitivity of 100% and specificity of 94.4%). The Fetal-7 scale is a valid tool for assessing acute pain-related behavior in third trimester fetuses and may be of value in guiding analgesic procedures efficacy in these patients. Further research is warranted to explore the presence of post-operative pain in fetuses and its effects afterbirth. PERSPECTIVE: Recordings with three-dimension ultrasound of human fetuses undergoing pre-operative anesthetic injections revealed complex facial expressions during acute pain, similar to those collected in newborns. This study presented the validation process and cut-off value of the Fetal-7 scale, paving the way for the study of pain before birth in humans.

Sorting pain out of salience: assessment of pain facial expressions in the human fetus.

INTRODUCTION: The question of whether the human fetus experiences pain has received substantial attention in recent times. With the advent of high-definition 4-dimensional ultrasound (4D-US), it is possible to record fetal body and facial expressions. OBJECTIVE: To determine whether human fetuses demonstrate discriminative acute behavioral responses to nociceptive input. METHODS: This cross-sectional study included 5 fetuses with diaphragmatic hernia with indication of intrauterine surgery (fetoscopic endoluminal tracheal occlusion) and 8 healthy fetuses, who were scanned with 4D-US in 1 of 3 conditions: (1) acute pain group: Fetuses undergoing intrauterine surgery were assessed in the preoperative period during the anesthetic injection into the thigh; (2) control group at rest: Facial expressions at rest were recorded during scheduled ultrasound examinations; and (3) control group acoustic startle: Fetal facial expressions were recorded during acoustic stimulus (500-4000 Hz; 60-115 dB). RESULTS: Raters blinded to the fetuses' groups scored 65 pictures of fetal facial expressions based on the presence of 12 items (facial movements). Analyses of redundancy and usefulness excluded 5 items for being of low discrimination capacity (P>0.2). The final version of the pain assessment tool consisted of a total of 7 items: brow lowering/eyes squeezed shut/deepening of the nasolabial furrow/open lips/horizontal mouth stretch/vertical mouth stretch/neck deflection. Odd ratios for a facial expression to be detected in acute pain compared with control conditions ranged from 11 (neck deflection) to 1,400 (horizontal mouth stretch). Using the seven-item final tool, we showed that 5 is the cutoff value discriminating pain from nonpainful startle and rest. CONCLUSIONS: This study inaugurates the possibility to study pain responses during the intrauterine life, which may have implications for the postoperative management of pain after intrauterine surgical interventions.

On the feasibility of accessing acute pain-related facial expressions in the human fetus and its potential implications: a case report.

INTRODUCTION: Although pain facial assessment is routinely performed in term and preterm newborns by the use of facial expression-based tools such as the Neonatal Facial Coding System, the assessment of pain during the intrauterine life has not been extensively explored. OBJECTIVE: Describe for the first time, an experimental model to assess and quantify responses due to acute pain in fetuses undergoing anaesthesia for intrauterine surgery recorded by high-resolution 4D ultrasound machines. METHODS/RESULTS-CASE REPORT: A 33-year-old pregnant woman had congenital left diaphragmatic hernia of poor prognosis diagnosed, and her fetus was treated by fetoscopic endotracheal occlusion. Later, during the removal of the fetal endotracheal balloon by ultrasound-guided puncture, we have recorded facial expressions of the foetus before and after the anaesthetic puncture by the use of 4D ultrasound recordings, which were presented to 3 blinded coders instructed to use the Neonatal Facial Coding System for acute pain facial coding. The procedure was safe and feasible. CONCLUSION: This is the first description of a recordable acute pain model in the human fetus by the use of a facial expression-based tool. The possibility to assess pain-related intrauterine behaviours would allow not only for the monitoring of the efficacy of anaesthetic procedures in the fetus but would also open the way to explore the evolution of pain-related facial responses during the fetal neurodevelopment. This method may pave the way for objective assessments of pain in fetuses, should it endure the steps of formal validation studies.