Hypotension

Key considerations: Tension pneumothorax, Cardiac tamponade, Massive pulmonary embolism

Cannot miss

Tension pneumothorax
Cardiac tamponade
Massive pulmonary embolism
Aortic dissection
Ruptured AAA
Septic shock
Anaphylaxis
Massive hemorrhage
Adrenal crisis
Neurogenic shock

Red flags

SBP <90 mmHg or MAP <65 mmHg
Altered mental status
Signs of end-organ hypoperfusion (oliguria, mottled skin, cool extremities)
Tachycardia with hypotension (shock index ≥1)
Distended neck veins (obstructive or cardiogenic cause)
Fever with hypotension (sepsis until proven otherwise)
Recent trauma or hemorrhage
Rash or angioedema (anaphylaxis)
Unequal blood pressures between arms (aortic dissection)
No response to initial fluid bolus

Workup

history: Timeline — sudden vs gradual onset; Associated symptoms — chest pain, dyspnea, fever, rash, bleeding; Recent trauma, surgery, or procedure; Medication changes — antihypertensives, diuretics, new medications; Known cardiac history — ejection fraction, prior MI; Signs of infection — fever, chills, dysuria, cough; Fluid losses — vomiting, diarrhea, bleeding, burns; Allergic exposure — new food, medication, insect sting; Adrenal history — steroid use or recent steroid discontinuation; exam: Vital signs — HR, BP both arms, RR, SpO2, temperature; Calculate MAP = (SBP + 2×DBP) / 3 — target ≥65; Calculate Shock Index = HR/SBP — ≥1 indicates significant shock; Mental status — confusion or agitation indicates cerebral hypoperfusion; Skin — pallor, mottling, diaphoresis, warmth (distributive), coolness (cardiogenic/hypovolemic); JVD — present suggests obstructive or cardiogenic, absent suggests distributive or hypovolemic; Lung auscultation — crackles suggest cardiogenic pulmonary edema; Abdomen — tenderness, pulsatile mass (AAA); Extremities — capillary refill, peripheral pulses, edema; Skin/mucous membranes — urticaria or angioedema (anaphylaxis); labs: CBC — hemoglobin (hemorrhage), WBC (infection); BMP — lactate is key marker of tissue hypoperfusion; Lactate — >2 mmol/L indicates significant hypoperfusion, >4 indicates severe shock; Coagulation panel — DIC screen; Type and crossmatch — if hemorrhage suspected; Blood cultures × 2 — if sepsis suspected (before antibiotics); Troponin — rule out cardiogenic cause; BNP/NT-proBNP — cardiogenic shock; Cortisol — if adrenal crisis suspected; ABG — metabolic acidosis indicates poor perfusion; Urinalysis — infection source; imaging: CXR — pneumothorax, pulmonary edema, widened mediastinum; POCUS/FAST — pericardial effusion, free fluid, IVC assessment (collapsibility indicates volume status); CT chest/abdomen/pelvis with contrast — if etiology unclear and patient stable enough; CT angiography — if PE or aortic dissection suspected; Echocardiogram — if cardiogenic shock suspected; bedside: ECG — arrhythmia, STEMI, right heart strain (PE); POCUS — IVC collapsibility (flat = hypovolemic, plethoric = obstructive/cardiogenic), cardiac function, lung sliding, free fluid; Urinary catheter — monitor urine output (target >0.5 mL/kg/hr); Arterial line — continuous BP monitoring in unstable patients

Management

immediate: Establish IV access — 2 large bore IVs or IO if unable; Place patient supine — legs elevated if not respiratory compromise; Supplemental oxygen — target SpO2 >94%; Identify and treat immediately reversible causes — tension PTX (needle decompression), tamponade (pericardiocentesis), anaphylaxis (epinephrine IM); Activate appropriate response — trauma activation, MTP, cath lab if STEMI; general: Determine shock category first — guides all subsequent management; Hypovolemic/Distributive: IV fluid resuscitation 500mL LR boluses, reassess after each; Cardiogenic: cautious fluids, early vasopressors, avoid fluid overload; Obstructive: treat the obstruction (needle decompression, pericardiocentesis, thrombolytics for massive PE); Target MAP ≥65 mmHg throughout resuscitation; Reassess after every intervention — shock is dynamic; specific: diagnosis: Septic Shock; steps: Blood cultures × 2 before antibiotics; Broad-spectrum antibiotics within 1 hour; 30 mL/kg IV crystalloid bolus; Norepinephrine if MAP <65 after fluids — first-line vasopressor; Target lactate clearance ≥10% at 2 hours; Source control; diagnosis: Hemorrhagic Shock; steps: Control external hemorrhage immediately; Activate MTP — 1:1:1 ratio pRBC:FFP:PLT; TXA 1g IV if within 3 hours of injury; Permissive hypotension SBP 80–90 until surgical control (avoid if TBI); Avoid aggressive crystalloid resuscitation; diagnosis: Cardiogenic Shock; steps: ECG immediately — STEMI requires emergent cath lab activation; Cautious fluid challenge 250mL if not clearly volume overloaded; Norepinephrine first-line vasopressor; Dobutamine if low cardiac output with adequate BP; Avoid aggressive diuresis acutely; Cardiology consult — mechanical support (IABP, Impella) consideration; diagnosis: Anaphylactic Shock; steps: Epinephrine 0.3mg IM lateral thigh immediately — do not delay; Remove or stop the trigger; IV fluid bolus 1–2L NS; Diphenhydramine 50mg IV + Famotidine 20mg IV; Methylprednisolone 125mg IV; Epinephrine drip if refractory to IM epinephrine; diagnosis: Adrenal Crisis; steps: Hydrocortisone 100mg IV bolus immediately; IV fluid resuscitation — normal saline 1–2L; Dextrose if hypoglycemic; Identify and treat precipitating cause; Continue hydrocortisone 50–100mg IV q6-8h; diagnosis: Neurogenic Shock; steps: IV fluids cautiously — avoid fluid overload; Norepinephrine preferred — addresses both hypotension and bradycardia; Atropine for symptomatic bradycardia; Spinal immobilization; Neurosurgery consult

Disposition

admit: All hemodynamically unstable patients require ICU admission; Any patient requiring vasopressors; Persistent lactate elevation after initial resuscitation; Undifferentiated shock requiring ongoing monitoring; Cardiogenic shock — cardiology ICU; discharge: Hypotension fully resolved with clear benign etiology (vasovagal, dehydration); Normal mental status, normal lactate, normal urine output after treatment; Reliable follow-up arranged; consults: Cardiology — cardiogenic shock, STEMI; Surgery — hemorrhagic shock, surgical source of sepsis; Interventional Radiology — hemorrhage control; Endocrinology — adrenal crisis; Pulmonology/Hematology — massive PE

Clinical pearls

Classify shock first — hypovolemic, distributive, cardiogenic, or obstructive. Each has a different treatment strategy and treating the wrong type can be harmful.
POCUS is your fastest diagnostic tool — IVC collapsibility, cardiac function, and free fluid can classify shock in under 2 minutes at the bedside.
Lactate is your resuscitation endpoint — not blood pressure alone. A patient can have a normal BP with markedly elevated lactate indicating occult shock.
Norepinephrine is first-line vasopressor for most shock states — it increases SVR without significantly increasing myocardial oxygen demand.
In cardiogenic shock avoid aggressive fluids — the heart cannot handle the volume and you will worsen pulmonary edema.

Source and review

Tintinalli Emergency Medicine 9th ed; Surviving Sepsis Campaign 2021; AHA Cardiogenic Shock Guidelines. Last reviewed: 2024-11-01