Final answer:
When systolic blood pressure falls below 80 mmHg in hypovolemic shock, the first step is to call for help, with subsequent management including administering oxygen, fluids, and potentially elevating the legs.
Step-by-step explanation:
If the systolic blood pressure falls below 80 mmHg in a patient experiencing hypovolemic shock, the first course of action would commonly be to call for help. Hypovolemic shock is typically caused by hemorrhage or fluid losses and is characterized by a rapid heart rate and low blood pressure. Immediate medical assistance is crucial to properly manage the patient's condition. Administering oxygen and fluids may be part of the subsequent treatment, and elevating the legs can help increase venous return to the heart; however, getting professional help is pivotal in coordinating these efforts safely and effectively.