Final answer:
The 4. intra-aortic balloon pump is a mechanical device that can increase coronary perfusion, cardiac output, and decrease myocardial workload and oxygen consumption in a patient with cardiogenic shock.
Step-by-step explanation:
The mechanical device that increases coronary perfusion and cardiac output while decreasing myocardial workload and oxygen consumption in a client with cardiogenic shock is the 4. intra-aortic balloon pump.
When in place, the intra-aortic balloon pump inflates during diastole and deflates during systole. This helps to increase coronary perfusion, improve cardiac output, and reduce the workload on the heart.
By reducing myocardial workload and oxygen consumption, the intra-aortic balloon pump can assist in stabilizing a patient in cardiogenic shock.
Other devices like the cardiac pacemaker, hypothermia-hyperthermia machine, and defibrillator may have their own uses in managing certain cardiac conditions, but they do not specifically address all the aspects mentioned in the question about cardiogenic shock.