A security review is under way at Waterford Regional Hospital after a nurse was held at knifepoint by a patient.
The man involved also ordered two other nurses to leave the ward where he had been receiving treatment.
Details of the events at the hospital early on Monday morning did not emerge until yesterday, when the Irish Nurses' Organisation attended talks at the Labour Relations Commission on Accident and Emergency Services.
What has been described as a sharp barber's blade was held to the nurse as she and her colleagues were taken from the eye unit, where they had been working an overnight shift, and brought through the hospital's A&E department.
Outside, the nurse was told by the man to open the door of a car.
When she could not do so, she broke free and ran back to the hospital with her colleagues.
The male patient - understood to be in his 40s - was eventually located by gardaí and returned to the hospital where he has since received psychiatric treatment.
The INO has received assurances from hospital management that the three nurses involved will receive an appropriate debriefing as well as any support that they need in coping with the incident.
INO Industrial Relations Officer, Mr Tony Fitzpatrick said their main concern was the apparent lack of security at the hospital, despite previous reviews.
"There are wall-mounted panic buttons in the A&E department, but these are only linked to other nursing staff and do not notify security personnel of an incident."
The South Eastern Health Board confirmed it is reviewing security at the hospital .