Final answer:
To determine the effectiveness of treatment for a patient in acute respiratory failure on mechanical ventilation, a nurse should assess the Arterial blood gases (ABGs), as they provide the most direct information regarding respiratory function and gas exchange.
Step-by-step explanation:
The best method for a nurse to use to determine the effectiveness of the current treatment regimen for a client in acute respiratory failure who is receiving mechanical ventilation is to assess the Arterial blood gases (ABGs). ABGs are a crucial diagnostic tool because they provide specific information on the patient's oxygenation status, carbon dioxide levels, and acid-base balance. This detailed information is essential for managing patients who are critically ill and have compromised respiratory function. While assessing blood pressure, capillary refill, and heart rate are important for monitoring the patient's overall cardiovascular status, they do not offer direct insight into the effectiveness of the mechanical ventilation on gas exchange.
Tests like pulse oximetry can also be used to measure the oxygen level in the blood, but ABGs give a more comprehensive evaluation of the patient's respiratory function. Since ABGs provide direct measurements of the pH, partial pressure of oxygen (PaO2), and partial pressure of carbon dioxide (PaCO2), they are considered the gold standard for determining the adequacy of ventilation and oxygenation in patients on mechanical ventilation.