My son has been in PICU 5 times this winter, ventilated (due to respiratory infections which he can't cope with due to chronic lung disease). One on occasion he got an awful pressure sore on one of his ears due to being lain prone (on his front). I was upset about the ear as it was very angry and painful looking during healing- plastics team has to come review it daily to assess whether ear was regaining shape etc. BUT in spite of being upset about the ear the bigger picture,which was more important to me, was that, thanks to the dedication of staff, my son was still alive! Not for a moment did I think that the injury arose due to lack of care for him- it is just, as previous posters have said, a risk associated with the sort of intensive care he was receiving.
The snot bubbles / secretions coming out of the nose - have had that too. It doesn't look nice but you can't hover over a patient with a suction catheter 24/7 to hoover them up the second they appear. In addition to which, suction is invasive and distressing, so you have to balance the frequency of doing it against the condition / clinical status of the patient.