Definition The primary physiologic goal when managing a tetralogy spell (cyanosis following a sudden increase in PVR) is reducing the right-to-left shunt (through the VSD), i.e. re-directing blood through the lungs. Pharmacologic management of tetralogy spells include β-blockade, alpha-agonism (increases both PVR and SVR, however if PVR is already elevated, does not have an additional […]