Guyler, director of strategy and integration at NUH said the situation was being regularly reviewed and was confident the trust would be able to return to normal operations soon.
He said: “Since Friday, colleagues have been working tirelessly to safely discharge hundreds of patients as part of efforts to increase capacity and relieve the pressure on our hospitals.
“Large numbers of staff have also volunteered to do extra shifts, and I want to thank all of our colleagues for their continued hard work, professionalism, and compassion throughout this difficult period.
“The situation has improved since Friday, but we still have large numbers of older patients with complex care needs, and we need to further improve our capacity to treat people with respiratory conditions before we can stand down from the critical incident which we have declared.”
Guyler apologised to any patients who had experienced extended waits for care.
NUH previously declared a critical incident in January due to winter pressures, which was stood down after two days.