31 The hypotensive/shocked patient and post-cardiac arrest Flashcards
What are peri-arrest, cardiac arrest, PEA and heart attack?
A patient in peri-arrest shows the symptoms and signs of a cardiac arrest but the heart is still beating.
A cardiac arrest is when the heart stops beating, normally caused by VF. This is an electrical issue.
Pulseless electrical activity (PEA) is a type of cardiac arrest in which there is electrical activity, but it is insufficient for contraction, therefore, there is no pulse.
A heart attack is when the flow of blood to the heart is blocked. This is a circulatory issue.
Patients with a cardiac arrest require CPR. VT and VF are shockable rhythms but asystole and PEA are not.
In post-cardiac arrest patients, the assessment of LV function directs the management of HF (e.g. optimal medical therapy).
What is hypovolemic shock?
A critical condition, characterised by hypotension, in which there is a severe loss of blood or fluid which decreases the CO.
What is the FEEL protocol and what is its role?
Th focused echo in emergency life support study uses the PLAX, PSAX, A4C and SC views to diagnose treatable issues in peri-arrest and cardiac-arrest settings. In patients in peri-arrest, the primary window is the subcostal window.
In patients in peri-arrest, TTE is important in identifying the possible reversible causes including pericardial effusion with cardiac tamponade (RA collapse, increased MV and TV E wave respiratory variation and dilated IVC with decreased respiratory collapse), hypovolemia (hyperdynamic heart and collapsed IVC), PE (PA dilatation, RV dilatation, TR, increased RAP and IVC dilatation) and an MI (RWMAs).
In patients with no pulse, TTE is important in identifying if it is true PEA (no contractile activity) or pseudo-PEA (contractile activity), because, if the patient is in PEA following a long resuscitation attempt, it may be time to call the time of death.
What are the echo characteristics of cardiogenic shock, hypovolemic shock and septic shock?
Cardiogenic shock is characterised by a normal or dilated LV (and RV) size, impaired LV (and RV) systolic function with possible RWMAs (if secondary to an MI), increased LV filling pressures and IVC dilatation with decreased inspiratory collapse. The small LV size with hyperdynamic function can cause cavity obliteration and dynamic LVOT obstruction.
Hypovolemic shock is characterised by a small LV size and normal RV size, normal or hyperdynamic LV systolic function with no RWMAs, normal or low LV filling pressures and a small IVC with good inspiratory collapse.
Septic shock is characterised by impaired global LV/RV systolic function, impaired diastolic function and LV/RV filling, ventricular interdependence (septal flattening during diastole), IVC dilatation with decreased inspiratory collapse and the possible presence of a pericardial effusion.
In patients in shock, the assessment of LV function directs the management of inotropes and vasopressors, and the assessment of LV size and IVC size and collapsibility directs the management of fluids.
