BACKGROUND: Unplanned extubation is a common occurrence in mechanically ventilated patients even in spite of careful attention. It is important to decide on reintubation or the retention of the extubated state especially in the critically ill patients. We tried to formulate general guideline for evaluation and safe management in unplanned extubated liver transplant patients with high risk of multiple organ failure and high mortality rate. METHODS: We reviewed all medical records of 5 unplanned extubated cases from 27 liver transplantation cases. We checked delayed extubation criteria which included United Network Organ Sharing (UNOS) class 1 or 2, preoperative Na (below 130 mEq) and albumin (below 3.0) level, transfusion amount in operating room, severity of postreperfusion syndrome (PRS) and need of vasopressor agents in the 5 unplanned extubated cases. We also checked direct intubation determining factors such as PaO2/FiO2 ratio, respiration rate and pattern, mental state and mode of ventilation. Finally, we reviewed additional factors influencing reintubation. RESULTS: We found a rate of 18 percent of unplanned extubation (5 of 27 events), and 80 percent of reintubation incidence (4 of 5 events). CONCLUSIONS: It is rational to reintubate immediately in unplanned extubated cases which meet 3 or more delayed extubation criteria. The direct reintubation determining factors are PaO2/FiO2 ratio (below 300) and the presence of paradoxical respiration with a high respiration rate (over 28/minute).