Which of the following factors can directly affect cardiac output?

D Crackles audible at the lung bases indicate the presence of pulmonary edema or fluid accumulation in the alveoli, which can compromise gas exchange and exacerbate respiratory distress. In a patient with ARDS, crackles suggest worsening pulmonary status and may indicate inadequate ventilation or oxygenation despite mechanical ventilation. Therefore, crackles at the lung bases are the most important finding to report to the healthcare provider as they may indicate a need for adjustments to the ventilator settings or additional interventions to optimize respiratory function and prevent further deterioration.

A respiratory rate of 22 breaths/min may be within an acceptable range, particularly considering that the patient is receiving mechanical ventilation. However, any significant deviation from the baseline respiratory rate or signs of respiratory distress, such as increased work of breathing or accessory muscle use, should be closely monitored and reported promptly.

B A heart rate of 106 beats/min may be within an acceptable range, although it is slightly elevated. Tachycardia can occur due to various factors, including pain, anxiety, fever, or hypoxemia. While tachycardia warrants close monitoring, it may not be the most critical finding to report unless it is associated with hemodynamic instability or other concerning symptoms.

C An oxygen saturation of 99% indicates adequate oxygenation, which is reassuring, particularly in a patient with acute respiratory distress syndrome (ARDS). However, oxygen saturation alone may not reflect the adequacy of ventilation or the severity of the underlying lung injury. Therefore, while oxygen saturation should be monitored closely, it may not be the most critical finding to report unless it declines significantly or is accompanied by other concerning symptoms.

A. Elective cardioversion involves the synchronized delivery of a therapeutic electrical shock to the heart to restore normal sinus rhythm in a patient with a tachyarrhythmia, such as atrial fibrillation or atrial flutter. However, ventricular tachycardia (VT) is a life-threatening arrhythmia characterized by a rapid heart rate originating from the ventricles, and it requires immediate intervention due to the risk of deteriorating into ventricular fibrillation (VF) and cardiac arrest. Therefore, elective cardioversion is not appropriate for treating VT.

B. Defibrillation involves the unsynchronized delivery of a high-energy electrical shock to the heart to terminate life-threatening arrhythmias, such as ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). In the case of a conscious patient with pulse-sustaining ventricular tachycardia, immediate defibrillation may not be necessary. However, if the patient deteriorates into pulseless VT or VF, prompt defibrillation is required to restore normal cardiac rhythm and circulation.

C. Radiofrequency catheter ablation is a procedure performed in a cardiac catheterization lab to treat certain cardiac arrhythmias by delivering radiofrequency energy to the specific area of the heart responsible for the abnormal rhythm. While radiofrequency catheter ablation may be considered for certain types of sustained ventricular tachycardia that are refractory to medical therapy or deemed to be originating from a specific site in the heart, it is not the immediate intervention for hemodynamically unstable ventricular tachycardia.

D. CPR is an emergency procedure performed on individuals experiencing cardiac arrest or a life- threatening medical emergency. In the case of ventricular tachycardia (VT) with a pulse, the patient is still perfusing, and CPR is not indicated. However, if the patient deteriorates into pulseless VT or ventricular fibrillation (VF), CPR may be initiated along with immediate defibrillation.