Overview and Implications
Shock is a condition of inadequate tissue perfusion. It is a clinical state that occurs when a mismatch arises between oxygen supply and metabolic demand, resulting in cellular hypoxia. If not recognized and treated appropriately, shock will ultimately progress to organ failure (Broussard & Ural, 2018; Gaieski & Mikkelsen, 2018; Vincent et al. 2013). It is one of the leading causes of death in hospitalized patients (Nichol & Ahmed, 2014).
There are several types of shock that a patient may experience during or after a procedure. Shock may be present when cardiac output is either decreased (low-flow) or increased (high-flow); examples of
low-flow shock states are hypovolemic, cardiac and obstructive shock, whereas a
high-flow shock state occurs in cases of distributive shock (Cecconi, 2014).
Table 1 below was created by Dr. Denny Laporta at the Jewish General Hospital, McGill University in Quebec (Laporta, 2018). The table summarizes the various types of shock that may be encountered in the peri-procedure period. In
hypovolemic shock the reduced cardiac output is due to a reduction in circulating volume and consequent venous return. It may be due to
hemorrhage or when large volumes of fluid are lost perioperatively – expectedly or unexpectedly.
Cardiogenic shock refers to cardiac pump failure. In other words, the heart is unable to pump enough blood to meet the body's demand for oxygen. Cardiogenic shock is most often caused by myocardial infarction, which may in turn be precipitated by physiologic stress associated with a procedure. Cardiac valvular disease or cardiomyopathy may also be contributing causes.
Distributive shock is when blood vessels dilate inappropriately, or more seriously, dilate and leak. Severe sepsis is the predominant form of distributive shock. Other disorders characterized by an acute and intense systemic inflammatory response (SIRS) such as anaphylaxis, comprise most – but not all - of the other causes of distributive shock occurring in the peri-procedure period.
Table 1: Examples of shock1 occurring during or after a procedure
|Bleeding||Myocardial Infarction||Pulmonary embolism||Septic syndrome|
Excess loss of non-blood fluid
- Cardiomyopathy (hypertrophic dilated)
Other (non-infectious) causes of systemic inflammatory response (SIRS)
- Transfusion reaction
|| ||Cardiac tamponade|
Other adverse drug reactions
|| || ||Spinal shock (neuraxial blockade)|
|| || ||Adrenal insufficiency (chronic steroid use)|
|| || |
- Liver failure
- Thyroid storm
1These may occur as single causes or in combination
Reduce the incidence of procedure-associated shock.
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