Obstructive shock

Obstructive Shock
SpecialtyCritical Care
CausesTension pneumothorax; cardiac tamponade; Budd chiari syndrome; pulmonary embolism; abdominal compartment syndrome; severe aortic stenosis; constrictive pericarditis; SVC syndrome
Diagnostic methodThorough history and physical exam; EKG; echocardiogram; X-ray; CT angiogram
Differential diagnosisCardiogenic shock; hypovolemic shock; distributive shock
TreatmentDepends on the cause of the obstruction

Obstructive shock is one of the four types of shock, caused by a physical obstruction in the flow of blood.[1] Obstruction can occur at the level of the great vessels or the heart itself.[2] Causes include pulmonary embolism, cardiac tamponade, and tension pneumothorax.[3] These are all life-threatening. Symptoms may include shortness of breath, weakness, or altered mental status. Low blood pressure and tachycardia are often seen in shock. Other symptoms depend on the underlying cause.[4]

The physiology of obstructive shock is similar to cardiogenic shock. In both types, the heart's output of blood (cardiac output) is decreased. This causes a back-up of blood into the veins entering the right atrium.[3] Jugular venous distension can be observed in the neck. This finding can be seen in obstructive and cardiogenic shock. With the decrease cardiac output, blood flow to vital tissues is decreased. Poor perfusion to organs leads to shock. Due to these similarities, some sources place obstructive shock under the category of cardiogenic shock.[1][5]

However, it is important to distinguish between the two types, because treatment is different.[6] In cardiogenic shock, the problem is in the function of the heart itself. In obstructive shock, the underlying problem is not the pump. Rather, the input into the heart (venous return) is decreased or the pressure against which the heart is pumping (afterload) is higher than normal.[7] Treating the underlying cause can reverse the shock.[1] For example, tension pneumothorax needs rapid needle decompression. This decreases the pressure in the chest. Blood flow to and from the heart is restored, and shock resolves.[8]

  1. ^ a b c Doerschug KC, Schmidt GA (2016). "Shock: Diagnosis and Management.". In Oropello JM, Pastores SM, Kvetan V (eds.). Critical Care. McGraw Hill. ISBN 978-0-07-182081-3.
  2. ^ Weil MH (May 2007). "Shock: Shock and Fluid Resuscitation". Merck Manual Professional. Archived from the original on 12 February 2010.
  3. ^ a b Walley KR (2014). "Shock". In Hall JB, Schmidt GA, Kress JP (eds.). Principles of Critical Care (4th ed.). McGraw Hill. ISBN 978-0-07-173881-1.
  4. ^ Haseer Koya M, Paul M (2021). "Shock". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID 30285387. Retrieved 2021-10-28.
  5. ^ Cotran RS, Kumar V, Fausto N, Robbins SL, Abbas AK (2005). Robbins and Cotran pathologic basis of disease. St. Louis, Mo: Elsevier Saunders. p. 141. ISBN 978-0-7216-0187-8.
  6. ^ Standl T, Annecke T, Cascorbi I, Heller AR, Sabashnikov A, Teske W (November 2018). "The Nomenclature, Definition and Distinction of Types of Shock". Deutsches Ärzteblatt International. 115 (45): 757–768. doi:10.3238/arztebl.2018.0757. PMC 6323133. PMID 30573009.
  7. ^ Funk DJ, Jacobsohn E, Kumar A (February 2013). "Role of the venous return in critical illness and shock: part II-shock and mechanical ventilation". Critical Care Medicine. 41 (2): 573–579. doi:10.1097/CCM.0b013e31827bfc25. PMID 23263572. S2CID 23603180.
  8. ^ Jalota R, Sayad E (2021). "Tension Pneumothorax". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID 32644516. Retrieved 2021-10-26.