The nurse is caring for a patient with a radial arterial line. Prior to obtaining a reading, which action is most appropriate?

Choice A rationale

Preload refers to the degree of stretch of the cardiac myocytes at the end of diastole, which is directly related to the volume of blood in the ventricles. In a patient with significant fluid loss from vomiting, diarrhea, and gastrointestinal bleeding, the intravascular volume is severely depleted. This leads to decreased venous return and low preload. Administering a fluid bolus increases the circulating volume, thereby improving preload and subsequent cardiac output.

Choice B rationale

Afterload represents the resistance the heart must pump against to eject blood into the systemic circulation. While systemic vascular resistance may increase as a compensatory mechanism in hypovolemia, a fluid bolus is not primarily intended to decrease afterload. In fact, increasing volume does not directly lower the resistance of the vessels. The primary goal in a bleeding and dehydrated patient is to restore the volume that contributes to the initial filling of the heart.

Choice C rationale

Increased preload is the desired result of the fluid bolus, not the underlying issue being treated. The patient currently suffers from a lack of volume, so their preload is low. If the preload were already increased, as seen in fluid overload or congestive heart failure, a fluid bolus would be contraindicated as it would worsen pulmonary edema and cardiac strain. The clinician uses the pulmonary artery catheter to confirm that low pressures indicate a need for volume.

Choice D rationale

Increased afterload occurs when the blood vessels are constricted, making it harder for the heart to pump. This is common in hypertensive crises or as a late response to shock. However, this patient has lost fluids and blood, which naturally points to a volume deficit. Treating increased afterload would involve vasodilators, not a fluid bolus. The clinical history of gastrointestinal loss clearly identifies a volume deficit as the primary pathological state requiring immediate fluid resuscitation.

Choice A rationale

Administering sedative or paralytic agents is typically performed prior to or during the actual intubation process to facilitate tube passage and prevent airway trauma. Once the tube is inserted and the cuff is inflated, the priority shifts to verification of placement rather than further sedation. Giving these drugs after insertion does not provide any diagnostic data regarding whether the tube is in the trachea or the esophagus.

Choice B rationale

A chest x-ray is the definitive gold standard for confirming the depth of endotracheal tube placement. It ensures the distal tip of the tube is positioned approximately 2 to 5 cm above the carina. While other methods confirm the tube is in the trachea, the x-ray is essential to ensure it has not migrated into the right mainstem bronchus, which would cause unilateral lung expansion and potential collapse.

Choice C rationale

End-tidal carbon dioxide detection provides immediate physiological feedback that the tube is located within the respiratory tract. Since CO2 is a byproduct of alveolar gas exchange, its presence in exhaled air indicates the tube is in the trachea rather than the esophagus. A colorimetric changer or capnography waveform is a primary tool used immediately after intubation to rule out esophageal placement before further interventions are performed.

Choice D rationale

Auscultation is a critical immediate step to verify bilateral lung expansion and rule out unintentional esophageal or endobronchial intubation. The nurse should listen for equal breath sounds over the midaxillary lines and ensure there are no gurgling sounds over the epigastrium. Epigastric sounds suggest the tube is in the stomach. Breath sounds must be assessed early to ensure both lungs are being ventilated prior to securing the device.

Choice E rationale

Arterial blood gases are useful for evaluating the long-term effectiveness of ventilation and oxygenation after the patient is stabilized on a ventilator. However, they are not used for the initial confirmation of tube placement because the results take too long to obtain. Verification must be instantaneous using physical assessment and CO2 detection to prevent hypoxia. Normal pH is 7.35 to 7.45, and normal PaO2 is 80 to 100 mmHg.