The focus of care for critically ill patients is, in general, the following: i. The patient’s vital signs are closely observed for stability through cardiac monitoring. The patient’s systolic blood pressure should be maintained above 100 mmHg, diastolic blood pressure should be maintained above 60 mmHg, heart rate should be controlled at 60-100 beats/min, and oxygen saturation should be controlled above 90%. Once the patient’s vital signs appear abnormal, it indicates that the patient’s condition is critical, and further improvement of relevant examination is needed to take active treatment. Second, for patients with indwelling gastric tube and abdominal drainage tube, observe the drainage flow, color and nature of the drainage tube and record them on time. For patients with bloody fluid in the gastric tube, it is necessary to consider whether there is combined gastrointestinal bleeding, and if necessary, gastroscopy needs to be improved. Third, record the patient’s 24-hour in and out volume to facilitate understanding whether the patient’s fluid rehydration is balanced. Avoid complications of electrolyte disorders such as hypokalemia and hyponatremia caused by too much rehydration and heart failure, or too little rehydration.