Hemodynamics at the Bedside

Blood pressure is a pressure signal, not proof that organs are receiving enough blood. Bedside hemodynamic reasoning connects pressure, flow, and tissue perfusion so that a seemingly acceptable MAP does not hide falling cardiac output. The working model is: - MAP ≈ cardiac output × systemic vascular resistance - Cardiac output = heart rate × stroke volume - Stroke volume is influenced by preload, afterload, and contractility. A patient with sepsis may maintain MAP through intense vasoconstriction while cardiac output and peripheral perfusion deteriorate. The experienced nurse therefore follows the trajectory: MAP and pulse pressure, heart rate and rhythm, mental status, capillary refill, skin, urine output, lactate, respiratory status, and response to treatment. The question is not simply whether the blood pressure is low; it is whether circulation is delivering oxygen and whether the current intervention is improving that delivery.