To verify the correct placement of an endotracheal tube (ET) after insertion, the best initial action by the nurse is to:

Mean arterial pressure (MAP) is a measure of the average pressure within the arteries during one cardiac cycle. It represents the perfusion pressure that drives blood flow to organs and tissues. MAP is calculated using the formula:
MAP = Diastolic blood pressure + 1/3 (Systolic blood pressure - Diastolic blood pressure)
Blood loss, particularly in cases of significant hemorrhage, leads to a decrease in blood volume. When blood volume decreases, there is less circulating blood available to generate pressure within the arterial system. This reduction in blood volume results in decreased MAP.
Therefore, in the case of massive blood loss after trauma, the student can correlate it with a lower blood volume, which in turn leads to a lower MAP. The decrease in blood volume reduces the perfusion pressure, compromising organ and tissue perfusion
A. It causes vasoconstriction and increased MAP in (option A) is incorrect because: While vasoconstriction can occur as a compensatory mechanism to maintain blood pressure, it does not necessarily lead to an increased MAP in the context of significant blood loss.
C. It raises cardiac output and MAP in (option C) is incorrect because Blood loss typically leads to a reduction in cardiac output due to decreased blood volume. Therefore, it does not raise cardiac output and MAP.
D. There is no direct correlation to MAP in (option D) is incorrect because: There is indeed a direct correlation between blood loss and MAP. As blood volume decreases, MAP decreases as well.
Therefore, the correct correlation between blood loss and MAP is that lower blood volume lowers MAP.

In this scenario, the patient's signs and symptoms suggest a state of shock, which can be caused by various factors, such as hypovolemia, cardiac dysfunction, or systemic vasodilation. The first priority in managing a patient in shock is to ensure adequate oxygenation and tissue perfusion. Administering oxygen at 100% per non-rebreather mask helps improve oxygen delivery to the tissues and supports vital organ function.
A. Placing the patient on a continuous cardiac monitor in (option A) is incorrect because it is an important step to monitor the patient's heart rhythm and identify any abnormalities. However, providing oxygen should take priority to address the potential hypoxemia and tissue hypoperfusion.
C. Inserting two 14-gauge IV catheters in (option C) is incorrect because it is crucial for establishing large-bore access for fluid resuscitation and medication administration. While it is an important step, addressing oxygenation takes precedence.
D. Drawing blood to type and crossmatch for transfusions in (option D) is incorrect because it is an important step in managing a patient in shock who may require blood products. However, ensuring adequate oxygenation through oxygen administration is the immediate priority.
Therefore, the nurse should act first on the order to administer oxygen at 100% per non-rebreather mask to support the patient's oxygenation and tissue perfusion.