11/28/2012 01:03 pm ET Updated Nov 28, 2012

Yoselyn Ortega Pleads Not Guilty: NYC Nanny Accused Of Killing Two Children Makes Plea From Hospital

By Irene Plagianos, DNAinfo Reporter/Producer

MANHATTAN SUPREME COURT — The nanny accused of stabbing two children to death in their Upper West Side home pleaded not guilty to their murders Wednesday.

Yoselyn Ortega, 50, was charged with killing 2-year-old Leo Krim and his 6-year-old sister Lucia in their family's West 75th Street apartment on Oct. 25.

The horrific scene was discovered by the children's mother, Marina Krim, who found their bodies in a bathtub, as Ortega was allegedly trying to slash her own throat.

Ortega, who has been under police guard in New York-Presbyterian/Weill Cornell Medical Center since the killings, was indicted last week after officers were finally able to interview her about the crime.

During Wednesday's supreme court arraignment, conducted in the hospital, Ortega remained under a white blanket, handcuffed to her bed and wearing a blue hair net.

She was wearing a neck brace and had a tracheostomy tube, but was breathing on her own. One of her hands shook throughout the hearing, which was translated into Spanish.

She appeared alert, but didn't speak during the 10-minute proceeding.

Her attorney, Valerie Van Leer-Greenberg, entered the plea on her behalf. She declined to talk to reporters after the proceeding.

Judge Lewis Bart Stone ordered her held without bail while she undergoes a psychiatric exam.

Van Leer-Greenberg told the judge her "client is profoundly, medically impaired and in need of medical attention."

Her next court date is Jan. 16.

Detectives were initially unable to question Ortega because she remained in a catatonic state after being put in a medically-induced coma, sources said.

Ortega had worked for the Krims for two and a half years. Her employers had even visited Ortega's family in the Dominican Republic, according to an online diary Marina Krim kept.

Ortega faces life without parole if convicted.