In critical care settings, physical restraint is, popular nursing procedure performed by critical care nurses to prevent delirious or irritable patients from disconnecting tubes and lines and to maintain patient safety. However, inappropriate physical restraint performance causes many adverse effects on patient outcomes. Aim: to evaluate the impact of ICU physical restraint standards on critical care nurse's knowledge, practice, and outcome among critically ill Adult and older adult patient outcome. Design: Quasi-experimental research designs and observational design pre-post assessment were used to assess nurse's knowledge and to observe their practices of PR use in ICUs at two-time intervals: before the intervention, at its completion, and 12 weeks after completion, whereas the effect on patients' complications was assessed before and after implementation. Tools for data collection: Three tools were used for collect data of this study. Tool I: Pre / Post-test A structured interview questionnaire for nurses: It was developed by the researchers. It consisted of three parts: part 1 Socio-demographic characteristics of critical care nurses, as age, sex, marital status, qualification etc. Part 2: Assess nurse's level of knowledge as regard with PR care standards. This part involves 31-items of multiple-choice questions to assess nurses' knowledge regarding patient restrain. Tool II: pre/post the critical care nursing practice observational checklist sheet for nurses: It included 17 steps divided into four domains: Assessment and preparation phase (6 items), application phase (5 items), post care and maintenance phase (5 items). and documentation (1 item). Tool III:  Consequences of restraining in the form of problems or complications outcome sheet: consists of two parts: Part 1: Socio- demographic characteristics of adult and older adult. Part 2: Consequences of PR in the form of problems or complications (outcome). Results: the results showed marked deficiencies in nurses' knowledge and practices before the physical restraint standard with significant improvements at the post and follow-up evaluations. Additionally, significantly improvement in patient outcomes (complication decreased) after the study intervention. Recommendation: this study suggests that a continuous training package in nursing standards can significantly improve nurses' knowledge and practice regarding physical restraining of ICU patients, with subsequent decreases in the rate of adverse effects of PR complications among these patients.