Assessment of the haemostatic profile through a viscoelastic coagulation monitor in preterm neonates with a gestational age below 32 weeks: an Italian multicentre prospective observational study

Objective To establish gestational-specific and postnatal-age-specific reference ranges for the viscoelastic coagulation monitor (VCM) in preterm neonates born before 32 weeks of gestation during the first 10 days of life. Design Multicentre, prospective observational study. Setting Four Italian neonatal intensive care units, July 2021 to June 2024. Patients Neonates born below 32 weeks’ gestation. After excluding infants with haemorrhagic events, culture-proven sepsis or exposure to ibuprofen, indomethacin or heparin, 127 infants formed the reference (‘healthy’) cohort. Main outcome measures VCM parameters (clotting time (CT), clot formation time, alpha angle, maximum clot firmness (MCF), lysis index at 30 min (LI30)) measured on days 1, 3 and 7–10 of life; analyses by gestational age, small-for-gestational-age (SGA) status and sampling technique. Results A total of 310 VCM traces were analysed in the reference cohort. CT decreased and MCF increased significantly from the first to the third sampling (both p<0.001), indicating a developmentally regulated procoagulant shift, with stable LI30. SGA neonates showed lower MCF at the first and second samplings (27 vs 35 and 27 vs 39 VCM units, both p<0.001), normalising by day 10 (42 vs 44.5, p=0.344), paralleling lower platelet counts. Heel-prick samples showed significantly shorter CT than other sampling methods at all time points, whereas MCF was comparable. Conclusions VCM demonstrates a developmentally regulated, balanced haemostatic profile in preterm neonates and provides a feasible, low-volume bedside alternative to conventional coagulation tests. The reference ranges reported here may support more rational neonatal transfusion practice; the shorter CT of heel-prick samples should be considered when interpreting results.