Critical care patient pain assessment (CPOT score) is a way to assess pain in critically ill patients based on four aspects: facial expression, physical activity, muscle tension, mechanical ventilation compliance (intubated patients) or vocalization (non-intubated patients), with the following criteria: 1. Facial expression: 0 points for relaxation without special expression; 1 point for facial muscle tension and frowning; 2 points for the presence of the above facial expression with eyes tightly closed and facial distortion. 2. Physical activity: 0 points for no activity or normal position; 1 point for the presence of resistance and defense activities; 2 points for attempts to sit up, climb up, restlessness, and disobedience to instructions. 3. Muscle tension: 0 points for relaxation without resistance; 1 point for stiffness and tension, resistance when limbs are flexed; 2 points for very tight and stiffness, strong resistance when limbs are flexed and inability to complete the limb extension and retraction movements. 4. Mechanical ventilation compliance or vocalization: (1) Mechanical ventilation (intubated patients): tolerance of the ventilator with no alarms is 0 points; intermittent alarms that can be stopped automatically, coughing but tolerable is 1 point; resistance to the ventilator is not synchronized and frequent alarms is 2 points. (2) Vocalization (non-intubated patients): 0 points for normal speech or no vocalization; 1 point for sighing and moaning; 2 points for crying and yelling. This assessment, with a total score of 0 to 8, is for postoperative or traumatized (except for brain injury) intensive care unit patients with intact motor function but who are unable to self-report pain and should be assessed by a physician or nurse.