The crossover cameo of Mandy Patinkin was able to happen as "Homicide: Life on the Street" executive producer Tom Fontana and "Chicago Hope" executive producer John Tinker are friends from their days working together on the earlier medical drama.
When the child's heart is removed for transplantation, they show the organ being placed in a cooler with the name "Chicago Hope" on it. They then show it being delivered to Dr. Jeffrey Geiger played by Mandy Patinkin at Chicago Hope Hospital.