Editing Shock (section)

=== '''Obstructive''' ===

** Tamponade
*** Rapid accumulation of pericardial fluid results in compression to cardiac chambers and subsequent diastolic failure (reduced preload)
*** Cardiac output reduces
*** Compensatory tachycardia to attempt to overcome the reduced output
** Tension pneumothorax
*** Increased intra-thoracic pressure compresses the mediastinal structures and prevents filling of SVC and IVC, leading to reduced preload
*** There is also increased pulmonary vascular resistance
*** Cardiac output is compromised
** PE
*** Increased pulmonary vascular resistance due to a combination of mechanical obstruction and hypoxic vasoconstriction
*** Increased right ventricular afterload compromises right-sided output, and prevents downstream left ventricular filling, which results in reduced overall cardiac output