Septic shock resuscitation and vasoactive support

Overview & Definition

Septic shock is the life-threatening circulatory failure that follows a dysregulated host response to infection. The problem is not the infection itself but the body's reaction to it: inflammation deranges blood vessel tone, leaks fluid out of the circulation, and weakens the heart, so that blood is no longer delivered to tissues in the amount they need. The child looks cold, mottled and poorly perfused long before the blood pressure falls, because children hold their pressure up by raising heart rate and squeezing down their blood vessels. Waiting for hypotension to diagnose shock is the classic, dangerous error. [1] [5]

The modern international definition is the Phoenix criteria, agreed in 2024. A child has paediatric sepsis when the Phoenix sepsis score totals 2 or more points across its organ-dysfunction domains, and paediatric septic shock when that sepsis includes at least one point of cardiovascular dysfunction. The cardiovascular component captures the children who need vasoactive medication, have a raised lactate despite fluid, or have a mean arterial pressure below the threshold for their age. This replaced the older Sepsis-2 framework because the old definition relied heavily on systemic inflammatory response criteria that are neither sensitive nor specific. [3] [11]

Resuscitation of septic shock is a race to restore oxygen delivery before cells are starved, run in parallel with finding and killing the organism. The first hour is decisive: airway and breathing are supported, circulation is restored with fluid and then vasoactive drugs, glucose and electrolytes are corrected, and source control with antibiotics and drainage is begun. The Surviving Sepsis Campaign 2026 children's guideline sets the structure, but every step is a reassessment loop rather than a fixed prescription, because the same fluid that rescues one child can drown another. [1] [2]