• Shock is a state of acute cardiocirculatory failure resulting in end-organ hypoxia and dysfunction.
• Promptly recognizing and treating shock is important as it is associated with high mortality
• Shock has many etiologies and is the final common pathway of death.
• Approach to undifferentiated shock requires simultaneous resuscitation and investigation.

Table 1 Categories of shock

Approach to undifferentiated shock

1. Recognize shock.

• No single clinical finding or investigation can rule in or rule out shock. Diagnosis is based on a combination of clinical findings.
• Shock is commonly associated with hypotension, but it can also occur with normal blood pressure.
• Shock red flags
  • Ill appearance.
  • Altered mental status.
  • HR > 100, MAP < 65, SBP < 90, shock index (SI) > 0.8.
  • RR > 20.
  • Urine output < 0.5 ml/kg/h.
  • Skin – cool peripheries, mottling, urticaria.
  • Lactate > 4 mM/L or arterial base deficit < -4mEq/L.

2. Primary survey (ABCDE)

• Airway: assess airway patency.
• Breathing: assess oxygenation and ventilation.
  • Consider the need for intubation and mechanical ventilation. Minimize induction agents to avoid hemodynamic collapse.
• Circulation: assess pulse, BP, telemetry, signs of obvious bleeding.
  • Obtain large bore peripheral IV access. Obtain intraosseous access if peripheral IV access is difficult. Do not delay resuscitation for central line access.
• Disability: assess for level of consciousness and signs of spinal cord injury.
• Exposure: assess skin for urticaria, angioedema (signs of anaphylaxis).
• Rule out conditions requiring immediate intervention: tension pneumothorax, massive hemothorax, cardiac tamponade, MI, significant arrhythmias, massive PE, anaphylaxis, hypovolemia.

3. Initiate empiric resuscitation unless the cause of shock is clear and is rapidly reversed.

• Fluid resuscitation.
  • Fluid challenge with 300-500 ml of a crystalloid solution over 20-30 min. Repeat according to fluid responsiveness based on changes in BP, HR, urine output.
  • Be cautious with excessive fluid administration, especially if suspecting cardiogenic shock or massive PE.
  • Colloids like albumin are theoretically better intravascular volume expanders but there is no evidence of mortality benefit over crystalloids.

• Consider vasoactive agents if hypotension persists (MAP <65) despite fluid resuscitation.
  • Typical first line agent is norepinephrine with initial dose of 0.2 mcg/kg/min. Norepinephrine can initially be given through peripheral IV until central line access is available.
  • Vasopressin and epinephrine infusions can be used as second-line agents for severe cases of shock.
• Consider the use of inotropes if suspecting cardiogenic shock. Dobutamine is commonly used as a first line agent.
• Start broad-spectrum antibiotics if suspecting sepsis. Early antibiotic therapy improves outcomes in sepsis.
• Consider empiric corticosteroids for chronic steroid users or shock refractory to vasopressors and fluid resuscitation. Options include dexamethasone 6 mg IV or hydrocortisone 100 mg IV.
• Sodium bicarbonate therapy for severe metabolic acidosis is commonly used but there is no evidence of mortality benefit.

4. Secondary survey focused on determining the cause of shock.

• History: trauma, infection, immunosuppression, corticosteroid use, exposure to allergen, chest pain, toxic ingestions.
• Head to toe examination.
• Point of care ultrasound (FAST, RUSH).
  • Recent systematic review suggests ultrasound measurement of IVC is not a reliable indicator of volume status.
• Suggested initial investigations.
  • Blood tests: ABG, lactate, CBC, serum chemistry, LFT, troponin, BNP, coagulation studies.
  • ECG – ACS.
  • CXR – heart failure or pneumonia.
  • CT scan depending on working differential.
• Consider placing arterial line and/or central line.

5. Reassess indicators of adequate hemodynamic support.

• MAP > 65 with clinical signs of adequate tissue perfusion (mental status, skin appearance, urine output).
• Decreasing serial lactate measurements.

6. Transition to ICU.

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5. Evans, Laura1; Rhodes, Andrew2; Alhazzani, Waleed3; Antonelli, Massimo4; Coopersmith, Craig M.5; French, Craig6; Machado, Flávia R.7; Mcintyre, Lauralyn8; Ostermann, Marlies9; Prescott, Hallie C.10; Schorr, Christa11; Simpson, Steven12; Wiersinga, W. Joost13; Alshamsi, Fayez14; Angus, Derek C.15; Arabi, Yaseen16; Azevedo, Luciano17; Beale, Richard18; Beilman, Gregory19; Belley-Cote, Emilie20; Burry, Lisa21; Cecconi, Maurizio22; Centofanti, John23; Coz Yataco, Angel24; De Waele, Jan25; Dellinger, R. Phillip26; Doi, Kent27; Du, Bin28; Estenssoro, Elisa29; Ferrer, Ricard30; Gomersall, Charles31; Hodgson, Carol32; Hylander Møller, Morten33; Iwashyna, Theodore34; Jacob, Shevin35; Kleinpell, Ruth36; Klompas, Michael37; Koh, Younsuck38; Kumar, Anand39; Kwizera, Arthur40; Lobo, Suzana41; Masur, Henry42; McGloughlin, Steven43; Mehta, Sangeeta44; Mehta, Yatin45; Mer, Mervyn46; Nunnally, Mark47; Oczkowski, Simon48; Osborn, Tiffany49; Papathanassoglou, Elizabeth50; Perner, Anders51; Puskarich, Michael52; Roberts, Jason53; Schweickert, William54; Seckel, Maureen55; Sevransky, Jonathan56; Sprung, Charles L.57; Welte, Tobias58; Zimmerman, Janice59; Levy, Mitchell60 Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021, Critical Care Medicine: November 2021 – Volume 49 – Issue 11 – p e1063-e1143

   doi: 10.1097/CCM.0000000000005337

   
   

1. Approach to shock

    

   
   

2. Rapid Ultrasound for Shock and Hypotension – the RUSH Exam