Critical patients generally have the following nursing routines: First, closely monitor the patient’s vital signs such as heart rate, pulse, blood pressure, oxygen saturation and other indicators of change, if the indicators of oxygen saturation progressive decline, often suggest that the patient is in a state of severe hypoxia, need to immediately give increased oxygen flow or replace the mask oxygen must be maintained at oxygen saturation above 90%. Second, if the patient is placed abdominal drainage tube, gastric tube and urinary catheter, it is necessary to record the amount, color and nature of drainage tube drainage for 24 hours. If there is bleeding in the drainage tube or a sudden increase in drainage fluid, ultrasound or CT examination should be performed as soon as possible to clarify the patient’s specific condition, and surgical exploration should be performed if necessary. Third, for elderly patients need to record the 24-hour in and out, the amount of in for out, to avoid patients too much rehydration, too little out and cause heart failure.