The causes of small blood pressure differential are as follows: 1, the differential pressure is reduced and arterial elasticity; 2, some differential pressure is reduced due to regurgitation, pericardial effusion, etc., can appear differential pressure; 3, there are also some patients with a decrease in blood pressure, can be reduced pulse differential; 4, patients with concurrent shock, can also appear in this situation, so for patients with reduced differential pressure, but also need to identify due to what causes the decrease in pulse differential pressure; 5, some Patients with valvular disease can also appear in this situation, so it is also necessary to identify the cause, what is the cause of the reduced differential pressure, this cause is very important, after clarifying the cause of this reduced differential pressure can be removed, in order to improve the differential pulse pressure.