ARISE FLUIDS — Vasopressors or Fluids in Early Septic Shock

1. Publication

• Title: Vasopressors or Fluids in Early Septic Shock
• Acronym: ARISE FLUIDS
• Year & Journal: New England Journal of Medicine, epublished June 11, 2026
• Citation: The ARISE FLUIDS Investigators, the ANZICS Clinical Trials Group, and the ACEM Clinical Trials Network. Vasopressors or fluids in early septic shock. N Engl J Med. 2026. doi:10.1056/NEJMoa2516225

2. Context & Rationale

Background: Septic shock resuscitation traditionally prioritizes early crystalloid, adding vasopressors when hypotension/hypoperfusion persists. Guidelines still suggest ≥30 mL/kg crystalloid (low-certainty evidence) but increasingly emphasize individualization. Excess positive fluid balance may worsen pulmonary/tissue edema and organ dysfunction; conversely, early vasopressors before adequate volume expansion may compromise regional perfusion. Prior trials (CLASSIC, CLOVERS) tested fluid restriction after full initial resuscitation was already complete; the earliest, pre-30-mL/kg ED decision point remained untested.

Research Question/Hypothesis: In adults presenting to the ED with early septic shock after 1000–2000 mL fluid, does a restricted-fluid, earlier-vasopressor strategy increase days alive and out of hospital (DAOH90) to day 90 compared with a greater-fluid, later-vasopressor strategy?

Why This Matters: Tests the exact bedside decision clinicians face after the first liter of fluid — more fluid, or vasopressors — using a patient-centered endpoint (DAOH90) rather than mortality alone in a setting with falling sepsis mortality.

3. Design & Methods

• Study Type: Investigator-initiated, multicenter, open-label, randomized, parallel-group superiority trial
• Setting & Centers: 51 sites (metropolitan/regional/rural), Australia, New Zealand, Ireland
• Population:
• Inclusion: Adults ≥18y, clinically suspected infection, SBP <90 or MAP <65 mmHg despite ≥1000 mL IV fluid over ≤60 min (incl. prehospital), lactate >2.0 mmol/L, ≥1 IV antimicrobial started; all criteria within 6h of ED presentation, randomized within 2h of final criterion
• Exclusions: Pregnancy; transfer from another facility; non-septic hypotension; >2000 mL fluid pre-randomization; >6h since ED presentation; >2h since final inclusion criterion; clinician judged strategy unsuitable; immediate surgery; treatment limitation; imminent death; underlying disease making 90-day survival unlikely; prior enrollment
• Intervention: Restricted-fluid/early-vasopressor: fluid resuscitation stopped after randomization; vasopressors started immediately, titrated to clinician-selected MAP target (peripheral administration permitted); 250 mL rescue boluses allowed for specific criteria; strategy for 6–24h
• Comparator: Greater-fluid/later-vasopressor: up to 1000 mL bolus within 60 min if MAP below target; additional 500 mL boluses as needed; total 30 mL/kg within 3h recommended; vasopressors started later per clinician judgment
• Blinding: Open-label (unavoidable for a visible hemodynamic strategy); management committee/statisticians blinded until analyses completed
• Statistical Power & Follow-Up: 1000 patients for 90% power to detect a 7-day absolute DAOH90 difference, two-sided α=0.05, with inflation for non-parametric distribution and loss to follow-up. Quantile mixed-effects regression at the median, site as random effect. Follow-up to day 90 (longer-term disability outcomes planned at 6/12 months).

4. Key Results

Not stopped early (planned DSMC interim analysis at 500 patients recommended continuation).

Subgroups: No credible responder group identified (lactate ≥3, APACHE II ≥15, prior fluid ≥1500 mL, respiratory-source sepsis all showed CIs crossing zero for DAOH90 difference).

5. Internal Validity Assessment

• Randomization & Allocation: Secure web-based system, 1:1, site-stratified, variable block sizes — robust concealment.
• Protocol Adherence & Separation: High adherence but real deviations: 14.8% of vasopressor-group patients received a fluid bolus >250 mL; 2.7% did not have vasopressors started per protocol; 2.5% of fluids-group patients did not receive a 500 mL bolus per protocol. Strong fluid/vasopressor-timing separation nonetheless achieved.
• Missing Data: 37/1000 excluded (no consent for data use); 963 in ITT analysis. 3 fluids-group patients lost to primary-outcome follow-up (multiple imputation used).
• Blinding & Detection Bias: Open-label; primary outcome largely objective, but ICU admission, pulmonary edema ascertainment, and discharge timing are performance-bias-susceptible.
• Overall Internal Validity Conclusion: Strong for the primary neutral finding — concealed allocation, near-complete follow-up, strong intervention separation, and prespecified analysis; more limited for clinician-reported complications given the open-label design.

6. External Validity Assessment

• Population Representativeness: Median age 68–69y, lactate 3.2–3.3 mmol/L, APACHE II 18, modified SOFA 4, median 1500 mL fluid pre-randomization — typical high-resource ED early septic shock population.
• Geography: Overwhelmingly Australian/New Zealand (one Irish site contributed 1 patient).
• Severity/Applicability: Day-90 mortality (14.4–16.4%) lower than many ICU septic shock cohorts — applies best to early-recognized ED septic shock in systems with rapid antimicrobials and close monitoring. Weaker for resource-limited settings (early vasopressor strategy increased ICU admission by 8.7pp, requiring monitored beds/infusion pumps/nursing ratios).
• Overall External Validity Conclusion: Strong for high-resource ED systems managing early septic shock after 1–2L fluid; limited for later, more severe, already-resuscitated, transferred, or resource-constrained populations.

7. Strengths & Limitations

Strengths:

• Large (1000-patient), multicenter trial filling the specific pre-30-mL/kg ED decision gap
• Patient-centered primary outcome (DAOH90) incorporating survival and hospital burden
• Clinically meaningful, well-documented separation in both fluid volume and vasopressor timing
• Protocol and SAP published before recruitment completion

Limitations:

• Open-label design; performance/ascertainment bias risk
• Pulmonary edema was clinician-reported, particularly vulnerable to reporting bias
• DAOH90 partly influenced by health-system discharge/rehabilitation practices
• Powered for a 7-day DAOH90 difference, not smaller patient-important differences or mortality
• Relatively low mortality population limited power for survival differences
• Early-vasopressor strategy increased ICU admission — a real resource-use tradeoff

8. Interpretation & Practice Impact

• Clinical Implications: After an initial 1–2L, stopping fluid escalation and starting vasopressors earlier did not improve DAOH90 versus continued fluid-forward therapy — fluid-sparing is safe and feasible but not superior.
• Mechanistic Coherence: Lower pulmonary edema with early vasopressors is biologically consistent with reduced fluid exposure, though open-label ascertainment tempers confidence.
• Systems-Level Takeaway: Supports individualized resuscitation after initial fluid loading, early recognition, and early antimicrobials — not a mandate for either strategy; resource implications (ICU admission) matter in constrained systems.

9. Controversies & Subsequent Evidence

• The 30 mL/kg question is narrowed, not settled. The 2026 Surviving Sepsis Campaign guideline continued to suggest ≥30 mL/kg crystalloid in the first 3h (low-certainty evidence, with a remark to individualize). ARISE FLUIDS tested a strategy after 1000–2000 mL, not zero-fluid resuscitation.
• Aligns with CLOVERS and CLASSIC: CLOVERS (stopped for futility): 14.0% vs 14.9% mortality, restrictive vs liberal. CLASSIC: 42.3% vs 42.1% 90-day mortality, restricted vs standard. ARISE FLUIDS fills the remaining ED-specific gap.
• Early vasopressors remain physiologically attractive but not outcome-proven as default: CENSER showed improved shock control by 6h (76.1% vs 48.4%) but no significant 28-day mortality difference (15.5% vs 21.9%). A 2025 systematic review suggested a mortality signal favoring early norepinephrine (OR 0.49, 95% CI 0.25–0.96) but flagged more data needed via trial sequential analysis. ARISE FLUIDS materially reduces enthusiasm for routine early vasopressors as an outcome-improving default strategy.

10. Summary & Executive Takeaway

Summary: ARISE FLUIDS randomized 1000 ED patients with early septic shock (after 1000–2000 mL fluid) to restricted-fluid/early-vasopressor or greater-fluid/later-vasopressor strategies. Intended separation was achieved (fluid volume and vasopressor timing), but the primary patient-centered outcome (DAOH90) was identical: 76 vs 76 days (P=1.00). Mortality, organ support, and other secondary outcomes showed no benefit; pulmonary edema was numerically lower with early vasopressors (0.6% vs 5.0%) but this is open-label-reported.

Overall Takeaway: After initial ED fluid resuscitation, routinely prioritizing earlier vasopressors and lower fluid volumes is feasible and reduces fluid exposure, but does not improve 90-day patient-centered outcomes compared with a more fluid-forward strategy — resuscitation should be individualized rather than dictated by either ideology.

11. Bibliography

• Shapiro NI, Douglas IS, et al; NHLBI PETAL Network. Early restrictive or liberal fluid management for sepsis-induced hypotension (CLOVERS). N Engl J Med. 2023;388:499-510.
• Meyhoff TS, Hjortrup PB, et al; CLASSIC Trial Group. Restriction of intravenous fluid in ICU patients with septic shock. N Engl J Med. 2022;386:2459-2470.
• Permpikul C, Tongyoo S, et al. Early use of norepinephrine in septic shock resuscitation (CENSER). Am J Respir Crit Care Med. 2019;199:1097-1105.
• Macdonald SPJ, et al; REFRESH Trial Investigators. Restricted fluid resuscitation in suspected sepsis associated hypotension. Intensive Care Med. 2018;44:2070-2078.
• Prescott HC, et al. Surviving Sepsis Campaign 2026 guideline. Intensive Care Med. 2026.