Oral care for patients on the mechanical ventilator is extremely vital in intensive care units, as the
problems developing from its negligence can cause long-term oral and nosocomial diseases such as ventilator-
associated pneumonia. Maintaining oral health in critically ill patients is an essential nursing activity, and the
state of a patient's mouth can be an index of nursing care received. Each critical nurse can play a functional role
in reducing and preventing the occurrence of VAP, subsequently improving the patients' recovery rate and
consequently reducing healthcare costs. This study aimed to assess the effect of oral hygiene for patients on a
mechanical ventilator in the intensive care unit and the nurses' knowledge and practice. Setting at the intensive
care units of Mansoura University Hospital. The Subjects included a convenient sample of all available nursing
staff working in the ICU, including 40 nurses, and a convenient sample of 60 orally intubated patients admitted
to the ICU who underwent mechanical ventilators. Tools of data collection were used for data collection are
nurses' knowledge questionnaire, nurses' observational checklist, and oral assessment scale. Results more than
three-quarters of the studied nurses had an unsatisfactory level of knowledge, and about three-quarters of them
had an incompetent level of practice regarding oral hygiene for patients on a mechanical ventilator. Meanwhile,
regarding the patients' total oral score, it was found that about half of the ventilated patients had average oral
alteration, and there was a highly significant relationship between oral alteration and frequency of oral care.
Conclusion the studied nurses' knowledge and practice were unsatisfactory and there was a highly statistically
significant relationship between low frequency of oral care and oral alteration. Also, there was a highly
statistically significant relationship between ventilator-associated pneumonia occurrence and poor alteration.
Recommendations health care settings should provide in-service educational programs and upgrading courses
based on evidence-based guidelines