Advanced Resuscitation with an Intact Cord in Preterm Lambs: A Feasibility Trial

Background: Preterm infants with bradycardia at birth often undergo immediate cord clamping (ICC) followed by resuscitation with positive pressure ventilation (PPV), chest compressions (CCs) and umbilical venous catheter (UVC) epinephrine. Resuscitation with an intact cord (PPV during delayed umbilical cord clamping-DCC) stabilizes cardiac output but delays UVC placement. Objective: To evaluate the feasibility of direct epinephrine injection into the umbilical vein during DCC (DCC + direct-epinephrine) compared with ICC and epinephrine administered through a UVC (ICC + cath-epinephrine), and to explore differences in return of spontaneous circulation (ROSC) and need for CCs between these approaches. Methods: Eleven preterm lambs (125-127 d gestation) were asphyxiated by cord compression to decrease heart rate (HR) to <30/min. In the ICC + cath-epinephrine group, the cord was immediately cut, lambs received PPV followed by CCs if HR < 60/min, and epinephrine was administered after UVC placement. In the DCC + direct-epinephrine group, cord compression was released when HR < 30/min and PPV was initiated. If HR remained <60/min, epinephrine was injected into the UV using a 25G needle. If ROSC was achieved, DCC was continued for 2 min. If HR < 100/min, the cord was cut and resuscitation was continued as outlined above. Plasma epinephrine concentrations were analyzed. Results: All lambs required epinephrine. Time to epinephrine was shorter with DCC + direct-epinephrine, 1.0 (0.7, 1.6) vs. 3.7 min (3.2, 5.2). Fewer lambs with DCC + direct-epinephrine needed CC (2/6 vs. 5/5, p = 0.06). ROSC success and plasma epinephrine concentrations were similar. Post-ROSC, heart rates and mean blood pressures tended to be higher in the ICC + cath-epinephrine group. Conclusions: In this perinatal lamb model of asphyxial bradycardia, resuscitation with an intact cord with direct umbilical venous epinephrine injection is feasible. Larger studies are required to determine whether this approach reduces the need for CC or improves clinically meaningful outcomes.