Helga Cocková, who played Irena Strosmajerová, was originally considered for a part of Marta Hunková, eventually played by Iva Janzurová.
Libuse Safránková was in the original cast. According to some sources, she was supposed to play Dr. Alzbeta Cenková, eventually played by Eliska Balzerová, according to others it was the part of nurse Ina, eventually played by Andrea Cunderlíková. In any case, she had to refuse because of her pregnancy.
The character of the head physician doctor Sova was written by Jaroslav Dietl for Karel Höger. Höger actually began filming the series, but died suddenly and the footage was re-shot with Ladislav Chudík.