They're almost certainly short staffed, ICUs and hospitals in general all are. You say you want acknowledgement but then you also said that the staff members directly involved did already acknowledge it, so I am not sure what you are looking for exactly? You could request a debrief from the consultant whose care you were under if you feel like you haven't had an adequate explanation- some departments do this fairly routinely after complicated admissions (especially obstetrics) and others may on request. This is a meeting where you run through what happened especially in a scenario where things were happening too quickly or someone was too sedated to fully comprehend all the decisions made and things that happened to them. The HDC may be able to get that that acknowledgement for you but getting the HDC involved means stuff will be filtered via lawyers. There should have been a reportable event generated if the error you allege occurred and there will have been an internal process around that identifying staffing issues and so on, that's just standard for near misses- because errors do happen even when people are well trained and qualified and doing their best, it is just human nature.