Pulmonary Embolism
PE occurs when a thrombus, generally a DVT, breaks loose and becomes lodged in one or more branches of the pulmonary artery. This results in a twofold problem affecting both the pulmonary and cardiac systems. Then lung tissue distal to the blockage becomes infarcted and does not allow blood flow to the regions affected. This causes a V:Q mismatch to occur because, although ventilation to this area occurs, there is no perfusion here, and therefore not gas exchange takes place. The occlusion in the pulmonary artery also affects the heart, in that there is significant increase in the afterload that is placed on the right ventricle. The RV is preload dependent and does not have the muscular development of its left side counterpart. This results in acute right sided heart failure. The body compensates for this by increasing HR and vasoconstricting, however this only works for so long before the RV will fail completely and cardiac arrest may occur.
Common signs and symptoms of PE include:
-Dyspnea
-Sharp, pleuritic chest pain
-Low SPO2 despite clear lung sounds
-Low ETCO2 (remember gas exchange is impaired)
-Hypotension
-Tachycardia
-Potentially ECG changes including: S1Q3T3, T wave inversions in V1 to V3, or T wave inversion in leads III and V1.
-Presence of a DVT or history suggestive of one.
Wells criteria may also be used to risk stratify for PE:
Patients at risk for PE include:
-Pts with prolonged immobility
-Recent surgery
-Pregnancy
-Use of hormone contraceptives
-Cancer patients
Treatment Plan:
-Recognize the signs!
-Supplemental Oxygen
-12-lead to rule out cardiac cause and look for supporting evidence of PE
-IV to support preload for the RV which is under stress.
-RAPID transport. (NOW).
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