ICCN Articles

The Sepsis Hour-1 Bundle Explained

By Javier Castaneda ·

Sepsis is a medical emergency in which the body’s response to infection injures its own tissues and organs. Because outcomes worsen with every hour of delay, the Surviving Sepsis Campaign distilled the most time-critical actions into the Hour-1 Bundle: a set of tasks clinicians aim to initiate within the first hour of recognizing sepsis or septic shock. This guide explains each element and the nuance behind it.

The Five Elements

  1. Measure lactate, and remeasure within 2 to 4 hours if the initial level is above 2 mmol/L, using the trend to gauge resuscitation.
  2. Obtain blood cultures before antibiotics, as long as this does not meaningfully delay them.
  3. Give broad-spectrum antibiotics promptly, targeting the likely source of infection.
  4. Start IV crystalloid for hypotension or a lactate of 4 mmol/L or higher; the guideline benchmark is 30 mL/kg.
  5. Add vasopressors if the patient remains hypotensive during or after fluids, targeting a mean arterial pressure of at least 65 mmHg.

Why Hour-1?

The clock starts at the moment of recognition, often at triage, not when every test has resulted. The bundle reframes sepsis as an emergency on par with stroke or myocardial infarction, where rapid, parallel action beats a slow, sequential workup.

The Nuance Clinicians Should Know

The bundle is a floor, not a ceiling. The fixed 30 mL/kg fluid target is debated, and many experts now favor a more individualized, dynamic approach to fluids, especially in patients with heart or kidney failure, using measures of fluid responsiveness rather than a single weight-based number. Antibiotic choice should match the suspected source and local resistance patterns, with early reassessment and de-escalation once cultures return. The goal is fast, sensible, patient-specific care, not box-checking.

The Bottom Line

The Hour-1 Bundle exists because in sepsis, time is tissue. Knowing the five elements cold, and the judgment behind each, lets any member of the team act decisively. For deeper, evidence-based analysis of sepsis and septic shock, explore more from the Interprofessional Critical Care Network.