The nurse is admitting a patient who is complaining of chest pain to the emergency department.
Which information collected by the nurse suggests that the pain is caused by an acute myocardial infarction?

Choice A rationale

Tracheal deviation is a classic and late sign of a tension pneumothorax, which is a life-threatening emergency. In a mediastinal context, shift of the trachea indicates significant pressure buildup in the thoracic cavity that can compress the heart and great vessels, leading to obstructive shock. This requires immediate needle decompression or chest tube adjustment. Normal tracheal position is midline, and any shift suggests a rapid compromise of respiratory and circulatory function necessitating urgent medical intervention.

Choice B rationale

Production of pink, frothy sputum often suggests pulmonary edema or minor airway irritation, but it is not the most acute finding specifically related to a mediastinal chest tube. While it requires assessment of oxygenation and heart failure markers, it does not represent the same immediate mechanical failure as a tension pneumothorax or massive hemorrhage. The nurse should monitor the patient's lung sounds and oxygen saturation, but other choices represent more direct and catastrophic complications.

Choice C rationale

Pain at the insertion site is an expected finding following the placement of a chest tube due to the stimulation of intercostal nerves and parietal pleura. While the nurse should provide adequate analgesia to facilitate deep breathing and prevent atelectasis, it is not an emergency requiring immediate intervention. Assessing the nature of the pain is important to rule out new complications, but it does not take priority over signs of hemodynamic or respiratory collapse in this scenario.

Choice D rationale

Sudden onset of shortness of breath is a hallmark sign of a recurring pneumothorax, tube occlusion, or pulmonary embolism. Rapid respiratory distress indicates that gas exchange is severely compromised, and the nurse must immediately assess breath sounds and the integrity of the chest drainage system. Rapid intervention is required to ensure the lung remains expanded and the patient is ventilated. This symptom reflects an acute change in clinical status that can lead to respiratory failure if ignored.

Choice E rationale

Drainage greater than 100 ml/hr from a mediastinal chest tube is a significant finding that may indicate active postoperative bleeding. While some drainage is expected, a rate exceeding this threshold requires immediate notification of the surgeon as the patient may require a return to the operating room for hemostasis. Excessive blood loss can lead to hypovolemic shock. Monitoring the trend of drainage is a standard nursing responsibility, and this specific volume is a widely recognized trigger for intervention.

Choice A rationale

Anxiety and fear typically trigger a sympathetic nervous system response, leading to an increased respiratory rate or hyperventilation. Hyperventilation results in the excessive elimination of carbon dioxide from the lungs, which decreases the partial pressure of arterial carbon dioxide. This process leads to respiratory alkalosis rather than acidosis. Therefore, psychological distress is a physiological driver for an alkaline state in the blood rather than the accumulation of carbonic acid seen in acidosis.

Choice B rationale

Central nervous system depression involves a decrease in the activity of the medullary respiratory centers, leading to hypoventilation. When the rate and depth of breathing are insufficient, the body cannot effectively clear carbon dioxide, which is a byproduct of cellular metabolism. This CO2 reacts with water to form carbonic acid, thereby lowering the systemic pH. Consequently, any condition that suppresses the brain's drive to breathe will directly contribute to the development of respiratory acidosis.

Choice C rationale

Diabetic ketoacidosis is a metabolic derangement characterized by the overproduction of ketone bodies, which are acidic. This condition leads to a primary decrease in bicarbonate levels and a drop in pH, which is classified as metabolic acidosis. While the respiratory system may attempt to compensate through Kussmaul respirations to blow off CO2, the underlying pathology is not a respiratory failure to clear CO2 but rather a metabolic accumulation of non-volatile organic acids.

Choice D rationale

Nasogastric suctioning involves the removal of gastric secretions, which are highly acidic due to the presence of hydrochloric acid. When these hydrogen ions are lost from the body in large quantities, it results in a relative excess of bicarbonate in the blood. This shift in the acid-base balance leads to metabolic alkalosis. Because the primary cause is the loss of gastric acid rather than a pulmonary ventilation defect, it cannot cause respiratory acidosis.

Choice E rationale

An overdose of sedatives, such as opioids or benzodiazepines, significantly slows the respiratory drive by affecting the central nervous system. This pharmacological suppression results in alveolar hypoventilation, where the exchange of gases is inadequate to meet metabolic demands. As carbon dioxide levels rise in the blood, the resulting hypercapnia leads to a decrease in pH. This is a classic etiology of respiratory acidosis, as the lungs fail to excrete the acid-forming gas.