What does the "three lows and one high" in shock refer to?

Generally, the "three lows and one high" in shock symptoms refer to low central venous pressure, low cardiac output, low arterial blood pressure, and elevated peripheral resistance. The "three lows and one high" are characteristic of hypovolemic shock. In such cases, both respiration and heartbeat may cease, requiring cardiopulmonary resuscitation (CPR) under medical guidance. A detailed analysis is as follows:

Central Venous Pressure

Central venous pressure (CVP) refers to the pressure at the point where the superior and inferior vena cava enter the right atrium. It is measured via catheter insertion into the superior or inferior vena cava or the right atrium. CVP reflects right atrial pressure and serves as one of the key clinical indicators for monitoring hemodynamics. It represents changes in pressure within the right atrium or the thoracic segment of the vena cava, reflecting the relationship between blood volume and right heart function. It aids in assessing shock status and guiding fluid replacement. A systolic blood pressure below 90 mmHg and pulse pressure below 20 mmHg generally indicate the presence of shock.

Cardiac Output

Cardiac output refers to the volume of blood pumped by the left or right ventricle per minute. Cardiac output varies with metabolic demands and physical activity. During shock, cardiac output decreases due to heart failure, leading to inadequate systemic circulation. Cardiac output is also one of the important clinical indicators.

Arterial Blood Pressure

Arterial blood pressure is the lateral pressure (or pressure intensity) exerted by blood on a unit area of the aortic wall, typically referring to the pressure within the aorta. When shock occurs, blood pressure falls below normal levels—systolic pressure below 90 mmHg and diastolic pressure below 60 mmHg—indicating reduced arterial blood pressure. Patients should promptly visit an internal medicine department at a hospital to identify underlying causes, such as severe infections from various pathogens, allergic reactions, pre-existing heart conditions, or traumatic hemorrhagic diseases, all of which can lead to shock. Immediate medical attention is essential when abnormal arterial blood pressure is detected to prevent disease progression.

Elevated Peripheral Resistance

When blood volume deficiency exceeds the body's compensatory capacity, clinical signs of shock syndrome appear. This manifests as decreased cardiac output. Despite peripheral vasoconstriction, blood pressure still drops. Reduced tissue perfusion promotes anaerobic metabolism, leading to increased blood lactate levels and metabolic acidosis. Therefore, elevated peripheral resistance is actually a protective mechanism.

When experiencing physical discomfort, it is crucial to seek timely attention. Treatment should be based on the underlying cause of shock; managing the primary disease is essential for recovery.