# Sepsis and Septic Shock: Early Recognition and Bundled Management

## Overview

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, as defined by the Sepsis-3 consensus. Septic shock is a subset with circulatory and metabolic dysfunction associated with higher mortality. Sepsis is the leading cause of in-hospital mortality, accounting for 1 in 3 hospital deaths. Treatment is profoundly time-sensitive, as delays in antibiotics and source control directly increase mortality. The "bundle" approach standardizes early management by packaging antibiotics, cultures, fluids, lactate measurement, and vasopressors into a coordinated protocol.

## Definitions (Sepsis-3, 2016)

### Sepsis

Sepsis requires suspected or documented infection plus acute organ dysfunction, defined as a SOFA score increase of 2 or more from baseline. SOFA components include PaO2/FiO2 ratio, platelets, bilirubin, MAP or vasopressor requirement, GCS, and creatinine or urine output.

### Septic Shock

Septic shock is defined as sepsis plus the requirement for vasopressors to maintain MAP at or above 65 mmHg AND a lactate above 2 mmol/L despite adequate fluid resuscitation. Mortality is 40 to 50%.

### qSOFA (Quick SOFA)

| qSOFA Criterion | Threshold |
|----------------|-----------|
| Respiratory rate | ≥22 breaths/min |
| Altered mentation | GCS <15 |
| Systolic blood pressure | ≤100 mmHg |

A score of 2 or more suggests possible sepsis and should prompt further assessment. However, it has important limitations: poor sensitivity as a screening tool means it should not be used to diagnose sepsis or to delay treatment, and it performs poorly in the ICU. SIRS criteria are no longer part of the sepsis definition but remain useful for clinical suspicion.

<image>Sepsis-3 diagnostic framework showing pathway from suspected infection through SOFA assessment to sepsis and septic shock classification with qSOFA as bedside screening tool</image>

## The Surviving Sepsis Campaign Bundles

### Hour-1 Bundle (Revised 2021)

The bundle requires measuring lactate (with remeasurement within 2-4 hours if elevated above 2 mmol/L to guide resuscitation), obtaining blood cultures before antibiotics (at least 2 sets, without delaying antibiotics to obtain cultures), administering broad-spectrum antibiotics ideally within 1 hour of sepsis recognition, providing rapid IV crystalloid resuscitation of 30 mL/kg for hypotension or lactate of 4 or higher, and starting vasopressors if hypotension persists during or after fluid resuscitation to maintain MAP at or above 65.

### Antibiotic Selection

Empiric broad-spectrum coverage targets the suspected source. For unknown source, vancomycin plus piperacillin-tazobactam, vancomycin plus cefepime, or meropenem is appropriate. Pneumonia calls for ceftriaxone plus azithromycin (CAP) or anti-pseudomonal plus vancomycin (HAP/VAP). Urinary sources are treated with ceftriaxone or fluoroquinolone for uncomplicated infections, or piperacillin-tazobactam or meropenem for complicated cases. Intra-abdominal sources are covered by piperacillin-tazobactam or meropenem. Skin and soft tissue infections may need vancomycin plus piperacillin-tazobactam for necrotizing infections or cefazolin for cellulitis. MRSA and Pseudomonas coverage should be considered based on local resistance patterns and risk factors. De-escalation within 48 to 72 hours based on cultures and clinical response is essential, and duration is 7 to 10 days for most infections with shorter courses supported for many conditions.

### Source Control

Identifying and controlling the source of infection as early as possible is critical. This includes draining abscesses, removing infected devices, and debriding necrotic tissue. Delays in source control beyond 6 to 12 hours increase mortality.

## Fluid Resuscitation

### Initial Resuscitation

The guideline recommends 30 mL/kg IV crystalloid within 3 hours of sepsis recognition. Balanced crystalloids (Lactated Ringer's, Plasmalyte) may be preferred over 0.9% normal saline based on the SMART trial (which showed lower composite of death, new renal replacement therapy, and persistent renal dysfunction), though the BaSICS and PLUS trials showed no difference and debate continues. Albumin can be considered if large-volume crystalloid is required to reduce total fluid volume. Hydroxyethyl starch (HES) must be avoided due to increased mortality and AKI demonstrated in the VISEP, 6S, and CHEST trials.

### Assessing Fluid Responsiveness

Dynamic measures are preferred over static ones. Passive leg raise with cardiac output measurement is the gold standard. Pulse pressure variation (PPV) or stroke volume variation (SVV) works in mechanically ventilated patients. IVC ultrasound assessing collapsibility can suggest volume responsiveness but has significant limitations. Static measures such as CVP are poor predictors of fluid responsiveness and should not be used as targets. The goal is to identify patients who will increase cardiac output with additional fluid versus those who will develop fluid overload.

<image>Fluid resuscitation and hemodynamic assessment in septic shock showing initial 30 mL/kg crystalloid, dynamic measures of fluid responsiveness (passive leg raise, pulse pressure variation), and vasopressor initiation thresholds</image>

## Vasopressor Management

### Norepinephrine — First-Line

Norepinephrine is an alpha-1 agonist (providing vasoconstriction) with some beta-1 activity (providing inotropy). It can be started via peripheral IV if central access is not immediately available, as short-term peripheral use is safe. It is titrated to maintain MAP at or above 65 mmHg.

### Vasopressin — Second-Line

Vasopressin is a V1 receptor agonist and non-catecholamine vasopressor given at a fixed dose of 0.03 to 0.04 units/min without titration. It is added to norepinephrine to reduce catecholamine dose. The VASST trial showed no overall mortality benefit but suggested possible benefit in less severe shock.

### Epinephrine — Alternative/Add-On

Epinephrine is an alpha plus beta agonist and potent inotrope, considered for refractory shock with cardiac dysfunction. It can cause tachyarrhythmias and lactic acidosis (through aerobic lactate production, which may confound lactate monitoring).

### Other Vasopressors

Phenylephrine is a pure alpha-1 agonist with limited role, considered only when tachyarrhythmias limit norepinephrine use. Angiotensin II (Giapreza) was effective in vasodilatory shock refractory to high-dose vasopressors in the ATHOS-3 trial but has limited clinical experience and is very expensive. Dobutamine, a beta-1 agonist, is used for sepsis-associated myocardial dysfunction with evidence of low cardiac output and considered if persistent hypoperfusion persists despite adequate MAP and volume status.

## Adjunctive Therapies

### Corticosteroids

Hydrocortisone 200 mg/day (50 mg IV every 6 hours or continuous infusion) is indicated for septic shock refractory to fluids and vasopressors. The ADRENAL trial showed faster shock reversal but no mortality benefit, while the APROCCHSS trial showed mortality benefit with hydrocortisone plus fludrocortisone. Corticosteroids are generally recommended when vasopressor doses are escalating despite adequate resuscitation.

### Other Adjuncts

The vitamin C/thiamine/steroid cocktail showed no significant benefit in the VITAMINS and VICTAS trials and is not routinely recommended, though IV thiamine 200 mg every 12 hours is reasonable given low risk and prevalence of thiamine deficiency in sepsis. A restrictive transfusion strategy targeting hemoglobin below 7 g/dL is standard (TRICC, TRISS trials), except with active hemorrhage or acute coronary syndrome. Glucose should be targeted below 180 mg/dL (NICE-SUGAR) with insulin infusion when persistently above 180.

<image>Vasopressor selection and escalation pathway in septic shock showing norepinephrine as first-line, vasopressin addition, and indications for epinephrine, dobutamine, and corticosteroids</image>

## Lactate-Guided Resuscitation

Lactate serves as a marker of tissue hypoperfusion and cellular metabolic stress. Serial measurements guide the adequacy of resuscitation, targeting lactate clearance of 20% or more every 2 hours or normalization. Rising lactate despite treatment indicates inadequate resuscitation or ongoing source of sepsis. Importantly, lactate is not specific for sepsis — other causes include liver failure, medications (epinephrine, metformin, linezolid), seizures, mesenteric ischemia, and thiamine deficiency.

## Monitoring and Endpoints of Resuscitation

Endpoints include MAP at or above 65 mmHg, urine output at or above 0.5 mL/kg/h, lactate normalization or significant downtrend, mental status improvement, and capillary refill time below 3 seconds (the ANDROMEDA-SHOCK trial showed capillary refill-guided resuscitation was non-inferior to lactate-guided). Central venous oxygen saturation (ScvO2) of 70% or above was an earlier target from the EGDT era but is less emphasized now.

## Clinical Pearls

Every hour of antibiotic delay in septic shock increases mortality by approximately 4-8%, so antibiotics should be administered first and narrowed later. Cultures before antibiotics should be the standard whenever possible, drawing them as antibiotics are being prepared rather than delaying antibiotic administration. CVP is not a reliable indicator of fluid responsiveness; passive leg raise with cardiac output monitoring is preferred. The 30 mL/kg fluid recommendation is a guideline not a mandate — reassess after each bolus, and some patients (heart failure, ESRD) may need less. The 1-hour antibiotic rule emphasizes urgency but should not penalize diagnostic uncertainty, as inappropriate antibiotics are also harmful. Norepinephrine can be safely started via a well-functioning peripheral IV without delaying vasopressors while obtaining central access. Procalcitonin can help guide antibiotic de-escalation and duration (downtrend supports stopping) but should not be used alone to initiate or withhold antibiotics.

## References
- Singer M, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). *JAMA*. 2016;315:801-810.
- Evans L, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. *Intensive Care Med*. 2021;47:1181-1247.
- Semler MW, et al. Balanced Crystalloids versus Saline in Critically Ill Adults (SMART). *N Engl J Med*. 2018;378:829-839.
- Venkatesh B, et al. Adjunctive Glucocorticoid Therapy in Septic Shock (ADRENAL). *N Engl J Med*. 2018;378:797-808.
- Hernandez G, et al. Effect of a Resuscitation Strategy Targeting Peripheral Perfusion Status vs Serum Lactate Levels on 28-Day Mortality (ANDROMEDA-SHOCK). *JAMA*. 2019;321:654-664.