Sepsis

Sepsis is a life-threatening medical emergency that occurs when the body’s response to infection becomes dysregulated and starts to damage its own tissues and organs. Rather than containing the infection locally, the immune system triggers a widespread inflammatory response that disrupts blood flow, impairs oxygen delivery to organs, and can cause multi-organ failure.

Sepsis can be caused by bacterial, viral, or fungal infections originating anywhere in the body, including the lungs (pneumonia), urinary tract, abdomen, skin, or bloodstream. It can develop from community-acquired infections or from hospital-acquired infections, including those associated with invasive devices such as central venous catheters or endotracheal tubes used in critical care.

In severe sepsis (now commonly referred to simply as sepsis with organ dysfunction), the cardiovascular system is often compromised: blood vessels dilate abnormally, fluid leaks out of circulation, and the heart muscle can be directly affected. This can produce a state called septic shock, characterised by dangerously low blood pressure that does not respond adequately to fluid replacement. Septic shock significantly increases the risk of cardiac arrest.

For cardiac arrest survivors in critical care, sepsis is an important and serious complication, particularly ventilator-associated pneumonia in mechanically ventilated patients and line-related bloodstream infections. Treatment involves prompt broad-spectrum antibiotics, source control (treating or removing the source of infection), intravenous fluids, and vasopressor medications to support blood pressure. Early recognition using NEWS2 (National Early Warning Score) and rapid escalation to critical care are central to NHS sepsis management.