Shock Series - part 6 of 6 Cardiogenic

Part 6 of 6 -Cardiogenic Shock

Recapping: Shock is a syndrome characterised by poor cellular perfusion. It can be preceded by

1. blood volume loss (Hypovolaemia),
2. obstruction of blood flow into the heart (obstructive),
3. failure to pump (cardiogenic), or
4. available blood being maldistributed (distributive).

In this final instalment we review Cardiogenic shock. As the name implies, cardio (heart)- genic (originates) is a form of shock that results in poor perfusion of cells secondary to the dysfunction of the heart.
Causes of mechanical pump failure are many and varied, but in the context of the trauma patient, a blunt or penetrating injury to the myocardium (heart muscle), or a traumatic myocardial infarction are all examples of a traumatic induced cardiogenic shock.
At the core of this type of shock is a patient with normal vascular tone and normal circulating volume, but with failure to effectively pump blood, cardiac output, blood pressure and tissue perfusion suffers.
Penetrating trauma is a surgical emergency. Ventricular lacerations require repair, and prognosis is poor. With normal healing process post trauma, inflammation causes altered cardiac compliance and force of contraction (inotropy), so outcomes are not good for traumatic cardiogenic shock patients.
Treatment for cardiogenic shock focuses on enhancing contractility, to improve cardiac output.
Positive inotropic infusions such as adrenaline and dopamine are used to increase cardiac contractility.
Anti arrhythmia medication is used to prevent arrhythmias, and nitrates to promote coronary perfusion.
Judicious IV fluids are used, as haemodilution and vascular overload are an unwanted complication.
In Summary:
Cardiogenic shock is a mechanical pump failure resulting in poor cardiac output.
Irrespective of the type of shock, all shock is life threatening. Be it a pump fail, loss of volume, obstruction or one of three types of maldistribution, cellular perfusion suffers, which is fundamentally, and quintessentially; shock.