Many patients set to attend hospitals for planned surgery yesterday had their operations cancelled due to pressure on beds, precipitated by A&E overcrowding.
More patients will have their operations cancelled today.
Dublin's Beaumont and Tallaght hospitals confirmed they had to cancel some elective surgery yesterday.
Planned surgery was also cancelled at Galway's University College Hospital, where there were 15 patients on trolleys early yesterday. That figure was down to six by last evening, a spokeswoman said.
Cork University Hospital has also cancelled some planned surgery for today due to pressure on beds. It had 22 patients on trolleys early yesterday.
Cavan General Hospital's A&E unit was also under serious pressure yesterday and this, combined with an outbreak of the winter vomiting virus in one of its medical wards, has resulted in elective surgery being cancelled for the remainder of this week.
The Irish Nurses Organisation was especially concerned yesterday at the numbers on trolleys in Cavan. There were 18 patients on trolleys awaiting beds yesterday morning, but the hospital's A&E department can only hold four trolleys. As a result patients were being cared for on trolleys in the X-ray department, the outpatients department and linking corridors.
"One patient is on his fifth day on a trolley and is likely to be discharged today never having seen a hospital bed. Another is on his fourth day on a trolley," Mr Tony Fitzpatrick, INO industrial relations officer, said.
He accused management at the hospital of having demonstrated "a reckless disregard" for patients and staff by failing to implement the terms of a 2002 A&E agreement.
The North Eastern Health Board, which runs the hospital, said the figure for the numbers on trolleys early in the day was not as high as 18 but was in fact 16.
"The hospital is putting in place its escalatory policy to deal with the current situation. Elective surgical procedures at the hospital have been postponed for the rest of the week. The hospital is arranging to open the day services unit to in-patient admissions. These measures will help to relieve pressure on the A&E department," it said in a statement.