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Undifferentiated shock

Updated Oct 21, 2026Adults · ED management20 sources · 13 checked in PubMed2 figuresESICM 2025

Bottom line

  • Hypotension is not required for shock. Look for tachycardia and poor perfusion: abnormal skin, low urine output and altered mentation. Measure lactate in every patient with suspected shock.1,2,3
  • Name the type: hypovolemic, cardiogenic, obstructive or distributive. Types can overlap. Echocardiography is the suggested first-line tool to tell them apart.1,3
  • Ultrasound sharpens the diagnosis, but has not shown a survival benefit. Immediate scanning put the right diagnosis first in 80% vs 50% of patients. In SHoC-ED, 30-day survival did not differ.4,5
  • Before giving more fluid after the first bolus, check whether the patient will respond. A fluid challenge is 200–500 mL over 5–10 minutes, with reassessment.1,2
  • Norepinephrine, not dopamine. In SOAP II, dopamine caused about twice the arrhythmias (24.1% vs 12.4%). Death rates were higher with dopamine in the cardiogenic shock subgroup. Start with a MAP of 65 or more, then individualize.2,3,6

First steps

  1. Monitor and examine often: heart rate, blood pressure, temperature, skin perfusion, urine output and mental status.3
  2. Check perfusion: time the capillary refill, and note skin temperature and mottling.1,2 Send a lactate.3
  3. Look at the context: trauma, infection, chest pain. The skin and the neck veins often point to the type.3
  4. Scan the heart early when the exam doesn't make the type clear.1,3
  5. Treat the cause and support the circulation together: fluids, and vasopressors if needed, with frequent reassessment.3
  6. If shock doesn't respond, or a vasopressor is running, place an arterial line and plan cardiac output or stroke volume monitoring.1,2

Recognize and classify

Shock is acute circulatory failure in which cells can't use enough oxygen. Lactate rises as a result.3 The usual definition of hypotension is a systolic pressure under 90 mm Hg, a MAP under 65, or a drop of 40 mm Hg or more from baseline. It is common but shouldn't be required for the diagnosis.3 Compensatory vasoconstriction can hold the pressure up while perfusion is already falling.3

TypeMechanism and examplesHemodynamic patternED share*
HypovolemicLost volume, internal or external (bleeding, fluid loss)Low cardiac output; low pressures and volumes30.8%
CardiogenicPump failure: ischemia, infarction, myopathy, myocarditis, major arrhythmiaLow cardiac output; raised pressures and volumes14.0%
ObstructivePulmonary embolism, tension pneumothorax, cardiac tamponadeLow cardiac output; high pulmonary pressure and a dilated right heart. Tamponade compresses all chambers.0.9%
DistributiveLost vascular tone: sepsis, anaphylaxis, spinal injuryUsually high cardiac output27.2% septic, 23.4% non-septic

Types and patterns from the ESICM consensus.3 *Shares are from 1,553 Danish ED patients with a systolic pressure of 100 mm Hg or less plus at least one organ failure. Another 3.7% had other conditions.7 In ICU patients from SOAP II, septic shock made up 62%, cardiogenic 17% and hypovolemic 16%.3 More than one type can coexist.3

The type predicts the outcome. In the Danish cohort, 7-day mortality ranged from 12.7% to 34.6% by type. Septic and cardiogenic shock independently predicted death within 7 days (HR 1.46 and 2.15).7

Shock index (heart rate ÷ systolic pressure)

Reference< 0.7
30-day death OR 2.90.7–1
30-day death OR 10.5≥ 1

From 111,019 first-time ED visits, with an overall 30-day mortality of 3.0%. The link was weaker in patients 65 or older (OR 8.2 vs 18.9 for younger patients), on beta- or calcium channel blockers (6.4 vs 12.3), or with hypertension (8.0 vs 12.9). A shock index of 1 or more still signaled high risk in every group.8

Bedside ultrasound

  • ESICM suggests echocardiography as the first-line imaging test for the type of shock (a graded statement), and says it changes management (good practice).1,2 The 2014 consensus noted that a basic look usually takes under 2 minutes, even for physicians with little training.3
  • Pooled accuracy (12 studies, 1,132 patients): sensitivity 0.78–0.90 and specificity 0.92–0.98 across the four types. The positive likelihood ratio was highest for obstructive shock (40).9
  • Faster, better diagnosis: in 184 ED patients with nontraumatic hypotension, the immediate-scan group had a median of 4 possible diagnoses at 15 minutes, vs 9 with delayed scanning. The final diagnosis was ranked most likely in 80% vs 50%.4
  • No survival benefit shown: SHoC-ED randomized 273 hypotensive ED patients (systolic under 100 mm Hg or shock index over 1). Survival was 104 of 136 with ultrasound vs 102 of 134 without. Fluid use, CT use and length of stay were also similar. The most common diagnosis was occult sepsis.5
TypeWhat the scan showsPooled sensitivityPooled specificity
ObstructiveDilated right heart; in tamponade, small, compressed chambers0.820.98
CardiogenicWeak contraction; large, high-pressure chambers0.780.96
HypovolemicSmall, underfilled chambers0.900.92
DistributiveHigh cardiac output0.790.96

Drawn for this page. Patterns from the ESICM consensus; accuracy from a 2023 meta-analysis.3,9 A right-to-left ventricular end-diastolic area ratio of 0.6 to 1 suggests moderate right ventricular dilation, and over 1 suggests severe dilation.3

Cardiac ultrasound image of a very large hemorrhagic pericardial effusion, with two arrows
FIG 1A very large pericardial effusion on ultrasound. A very large hemorrhagic pericardial effusion caused by malignancy, as described by the image's author.James Heilman, MD · Wikimedia Commons · CC BY-SA 3.0

The IVC is a weak guide on its own. In SHoC-ED patients breathing spontaneously, an IVC over 2.5 cm that collapsed less than 50% detected volume overload with a sensitivity of 85.7% and specificity of 86.4%. Only 7 of 125 patients were overloaded.10 ESICM warns against steering fluids by any single static preload number.2,3

Does scanning help?

ESICM supports echo as the first look at shock type.1,3 SHoC-ED found no survival gain.5 Reviewers note that the trial stopped early (273 of 400 planned) for slow recruitment and futility. They also note that no change in management was recorded after the scans, and that a diagnostic test may be a poor fit for a mortality endpoint.11

Lactate and capillary refill

  • Lactate: measure it whenever you suspect shock. It is usually above 2 mmol/L (2 mEq/L) in shock. Repeat it to guide treatment: about every 2 hours for the first 8 hours, then every 8–12 hours.3
  • Lactate beats blood pressure for prognosis, but it can rise for reasons other than poor perfusion.3
  • Capillary refill time is ESICM's first skin-perfusion check, with skin temperature and mottling as add-ons.1,2
  • After a fluid bolus, judge the effect on capillary refill, mottling, venous oxygen saturation, CO2-derived values and lactate.2

What the trials show (septic shock only)

  • ANDROMEDA-SHOCK (n = 424, 28 ICUs): an 8-hour protocol targeting capillary refill vs lactate. 28-day mortality was 34.9% vs 43.4% (HR 0.75, 95% CI 0.55–1.02), not significant. Organ dysfunction at 72 hours was lower (mean SOFA 5.6 vs 6.6).12
  • ANDROMEDA-SHOCK-2 (n = 1,467, 86 centers): a personalized protocol targeting capillary refill, including fluid responsiveness and bedside echo, beat usual care on a composite outcome (win ratio 1.16, 95% CI 1.02–1.33). The gain came mostly from a shorter duration of vital support.13
FIG 2The reassessment clock. Drawn for this page. A fluid challenge is given over 5–10 minutes and then judged.2 Lactate is repeated about every 2 hours for the first 8 hours.3 The ANDROMEDA-SHOCK protocol ran over the first 8 hours.12 Escalate monitoring if there is no response or a vasopressor is needed.2

Fluids, vasopressors and inotropes

Fluids

  • Too little and too much fluid both harm. Start fluids at once when preload is obviously very low, as in overt bleeding.3
  • After the first fluids, check fluid responsiveness before giving more, and weigh the expected benefit against the risk.1,2
  • Use dynamic tests over static values such as CVP. Don't target a set CVP.1,2,3 ESICM strongly recommends passive leg raising in ventilated patients, with or without spontaneous breaths (high certainty).2

Blood pressure targets

SituationTarget
Most shockStart at MAP ≥ 65 mm Hg, then individualize2,3
Cardiogenic shockAn initial MAP ≥ 65 may be considered2
Septic shock with chronic hypertension, or high CVPA higher MAP may be considered if the patient improves with it2
Trauma, uncontrolled bleeding, no brain injurySystolic 80–90 mm Hg (MAP 50–60) until major bleeding is stopped2
Traumatic brain injury with GCS ≤ 8MAP ≥ 80 mm Hg2

Drugs

AgentAdult doseNotes
Vasopressors
NorepinephrineStart 8–12 mcg/min, then titrate. Average maintenance 2–4 mcg/min.Fewer arrhythmias than dopamine in SOAP II. The label says to correct hypovolemia first.6,14
Epinephrine0.05–2 mcg/kg/min, titrated to MAPLabeled for hypotension in septic shock.15
VasopressinSeptic shock: start 0.01 units/min; range 0.01–0.07 units/minTitrate by 0.005 units/min every 10–15 min.16
DopamineNot first lineMore arrhythmias than norepinephrine. Higher mortality in cardiogenic shock.6
Inotrope
DobutamineStart 0.5–1 mcg/kg/min; usual range 2–20 mcg/kg/minOnly for poor cardiac function with low output and hypoperfusion after preload is optimized.3,17
Extravasation
Phentolamine5–10 mg in 10–15 mL normal saline, infiltrated into the areaInfiltrate as soon as possible after norepinephrine extravasation.14

Unreviewed doses. Verify against the current label and your institution's protocol before giving anything.

Doses from the FDA labels. Follow institutional protocols for concentrations and titration.

  • SOAP II (n = 1,679 with shock): 28-day mortality was 52.5% with dopamine vs 48.5% with norepinephrine, not significant. Arrhythmias were 24.1% vs 12.4%. Among 280 patients with cardiogenic shock, dopamine was linked to more deaths.6
  • Don't give inotropes for a weak heart alone. Add them only when low output and hypoperfusion persist after preload is optimized.3

Peripheral vasopressors

  • In 7 studies (1,382 patients), extravasation occurred in 3.4%. No tissue necrosis or limb ischemia was reported, and all events were managed conservatively or with vasodilators.18
  • In 9 studies (1,835 patients), 7% had complications and 96% of those were minor. Complications were less common where studies used a safety protocol (2.9% vs 12%).19
Sources differ

The norepinephrine and epinephrine labels say to infuse into a large vein.14,15 Reviews of peripheral infusion found extravasation uncommon and rarely serious, mostly with short infusions under close watch.18,19 The 2014 ESICM consensus said central access may be preferred once ICU patients need vasopressor infusions.3 For septic shock, the 2026 Surviving Sepsis Campaign suggests starting vasopressors peripherally rather than waiting for central access (conditional, very low certainty).20

Disposition

  • Shock that doesn't respond to initial therapy, or needs a vasopressor, calls for an arterial line, cardiac output or stroke volume monitoring, and serial echo.1,2 Admit to a setting that can provide them.
  • Patients who respond quickly don't need routine cardiac output measurement.3
  • Expect high early mortality: 7-day mortality reached 34.6% in cardiogenic shock and 30.3% in septic shock in ED patients.7

Pitfalls

  • Waiting for hypotension. Pressure can hold up while perfusion falls.3
  • Trusting a normal shock index in older patients or those on beta- or calcium channel blockers. Its signal is weaker there.8
  • Relying on one number, such as a single CVP, IVC size or lactate.3,10
  • Giving fluid after fluid without checking responsiveness.1,2
  • Reaching for dopamine. It caused twice the arrhythmias in SOAP II.6
  • Treating the pressure and forgetting the cause: bleeding, tamponade, tension pneumothorax, pulmonary embolism, sepsis.3

How strong is the evidence?

The 2025 ESICM guideline made 50 statements. Where strong evidence was lacking, the panel issued ungraded good practice statements, and most statements in the official summary are of that kind.1,2 It addresses adult ICU patients, so ED use is an extrapolation.1 The best perfusion-target trials enrolled only septic shock.12,13 The ultrasound trials are small, and SHoC-ED stopped early.4,5,11 SOAP II is the largest vasopressor trial across shock types.6 Peripheral vasopressor data come from observational studies.18,19

On-shift teaching

Questions to ask a learner at the bedside. Tap a question to see the answer. Every answer uses facts cited above.

Q1Does a patient need to be hypotensive to be in shock?
No. Hypotension (systolic under 90, MAP under 65, or a 40 mm Hg drop) is common but not required. Look for signs of poor perfusion in the skin, the kidneys and the brain.3
Q2Name the four types of shock and the most common in ED patients.
Hypovolemic, cardiogenic, obstructive and distributive.3 In a Danish ED cohort, hypovolemic shock was most common (30.8%), then septic (27.2%). Obstructive shock was rare (0.9%).7
Q3What does a shock index of 1 or more mean?
In 111,019 ED visits, it carried an adjusted OR of 10.5 for 30-day death, vs 2.9 for 0.7–1. The link is weaker in older patients and in those on beta- or calcium channel blockers.8
Q4If ultrasound improves diagnosis, why didn't SHoC-ED show better survival?
Immediate scanning put the right diagnosis first in 80% vs 50%.4 SHoC-ED found similar survival (104 of 136 vs 102 of 134).5 The trial stopped early, and no management changes after scanning were recorded.11
Q5Why norepinephrine over dopamine?
In SOAP II, mortality didn't differ overall (52.5% vs 48.5%), but dopamine caused more arrhythmias (24.1% vs 12.4%) and was linked to more deaths in cardiogenic shock.6
Q6What is a fluid challenge, and how do you judge it?
200–500 mL over 5–10 minutes. Judge the response by capillary refill, mottling, venous oxygen saturation, CO2-derived values and lactate.2

References

  1. 1
    Monnet X, Messina A, Greco M, et al. ESICM guidelines on circulatory shock and hemodynamic monitoring 2025. Intensive Care Med. 2025;51(11):1971–2012.GuidelinePMID 41236566DOIPubMed record; full text not openly accessible
  2. 2
    European Society of Intensive Care Medicine. ESICM guidelines on circulatory shock and hemodynamic monitoring 2025: visual abstract and announcement.SummaryVisual abstract (PDF)esicm.orgPage read
  3. 3
    Cecconi M, De Backer D, Antonelli M, et al. Consensus on circulatory shock and hemodynamic monitoring. Task force of the European Society of Intensive Care Medicine. Intensive Care Med. 2014;40(12):1795–1815.ConsensusPMID 25392034PMCFull text read
  4. 4
    Jones AE, Tayal VS, Sullivan DM, et al. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Crit Care Med. 2004;32(8):1703–1708.RCTPMID 15286547PubMed
  5. 5
    Atkinson PR, Milne J, Diegelmann L, et al. Does point-of-care ultrasonography improve clinical outcomes in emergency department patients with undifferentiated hypotension? An international randomized controlled trial from the SHoC-ED investigators. Ann Emerg Med. 2018;72(4):478–489.RCTPMID 29866583PubMed
  6. 6
    De Backer D, Biston P, Devriendt J, et al. Comparison of dopamine and norepinephrine in the treatment of shock (SOAP II). N Engl J Med. 2010;362(9):779–789.RCTPMID 20200382PubMed
  7. 7
    Gitz Holler J, Jensen HK, Henriksen DP, et al. Etiology of shock in the emergency department: a 12-year population-based cohort study. Shock. 2019;51(1):60–67.CohortPMID 27984523PMCPubMed
  8. 8
    Kristensen AK, Holler JG, Hallas J, et al. Is shock index a valid predictor of mortality in emergency department patients with hypertension, diabetes, high age, or receipt of β- or calcium channel blockers? Ann Emerg Med. 2016;67(1):106–113.e6.CohortPMID 26144893PubMed
  9. 9
    Yoshida T, Yoshida T, Noma H, et al. Diagnostic accuracy of point-of-care ultrasound for shock: a systematic review and meta-analysis. Crit Care. 2023;27(1):200.Meta-analysisPMID 37231510PMCPubMed
  10. 10
    Dunfield R, Ross P, Dutton D, et al. SHoC-IVC: does assessment of the inferior vena cava by point-of-care ultrasound independently predict fluid status in spontaneously breathing patients with undifferentiated hypotension? CJEM. 2023;25(11):902–908.Diagnostic studyPMID 37755657PubMed
  11. 11
    The Bottom Line. SHoC-ED: point-of-care ultrasound in undifferentiated hypotension (trial summary and critique).FOAMthebottomline.org.ukPage read
  12. 12
    Hernández G, Ospina-Tascón GA, Damiani LP, et al. Effect of a resuscitation strategy targeting peripheral perfusion status vs serum lactate levels on 28-day mortality among patients with septic shock: the ANDROMEDA-SHOCK randomized clinical trial. JAMA. 2019;321(7):654–664.RCTPMID 30772908PMCPubMed
  13. 13
    ANDROMEDA-SHOCK-2 Investigators; Hernandez G, Ospina-Tascón GA, et al. Personalized hemodynamic resuscitation targeting capillary refill time in early septic shock: the ANDROMEDA-SHOCK-2 randomized clinical trial. JAMA. 2025;334(22):1988–1999.RCTPMID 41159835PMCPubMed
  14. 14
    Norepinephrine bitartrate in sodium chloride injection. FDA prescribing information (DailyMed).Drug labelDailyMedLabel text read
  15. 15
    Adrenalin (epinephrine in sodium chloride) injection. FDA prescribing information (DailyMed).Drug labelDailyMedLabel text read
  16. 16
    Vasopressin injection. FDA prescribing information (DailyMed).Drug labelDailyMedLabel text read
  17. 17
    Dobutamine in dextrose injection. FDA prescribing information (DailyMed).Drug labelDailyMedLabel text read
  18. 18
    Tian DH, Smyth C, Keijzers G, et al. Safety of peripheral administration of vasopressor medications: a systematic review. Emerg Med Australas. 2020;32(2):220–227.ReviewPMID 31698544PubMed
  19. 19
    Tran QK, Mester G, Bzhilyanskaya V, et al. Complication of vasopressor infusion through peripheral venous catheter: a systematic review and meta-analysis. Am J Emerg Med. 2020;38(11):2434–2443.Meta-analysisPMID 33039229PubMed
  20. 20
    Society of Critical Care Medicine. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2026 (recommendation summary).Summarysccm.orgPage read
How this page was made
  • Written from scratch. No source text was copied; facts are restated and cited.
  • The 2025 ESICM guideline's full text was not openly accessible (publisher and repository copies blocked automated access). Its statements come from the PubMed abstract and ESICM's official visual abstract and announcement page, cited to both. The open full text of the 2014 ESICM consensus was read for definitions, lactate and echocardiography detail. Where the two differ, the 2025 statement is used.
  • Both ESICM documents address adult ICU patients. No ACEP clinical policy on shock exists. Trial results were checked against their PubMed abstracts. Doses come from FDA labels on DailyMed. Pediatric shock is not covered.
  • The 2026 Surviving Sepsis Campaign position on peripheral vasopressors comes from the Society of Critical Care Medicine's official summary page.
  • Figure 2 and the tables were drawn for this page from cited data. Figure 1 is an openly licensed image from Wikimedia Commons, credited under the image, and keeps its own license.
  • Not for clinical use until physician review.
Not for clinical use

AI-generated draft. Not reviewed by a physician. This page is for education only and may contain errors, including in doses. Do not use it to diagnose, treat or make decisions about any patient. Rely on your own clinical judgment, your institution's protocols and current drug labeling. Reading this page does not create a physician-patient relationship. Full terms