Pulmonary CCRN study questions (Answered Correctly)

A patient presents with labored breathing and an RR of 40 beats per minute (bpm). The following ABG is obtained: PaO2 68 PaCO2 50 pH 7.34 SaO2 91% HCO3 22 Which of the following is the most accurate interpretation of the above situation? A. Normal ABG for COPD patient B. Respiratory failure due to metabolic acidosis C. Obstructive upper airway most likely causing respiratory failure D. Respiratory failure due to dead space correct answers D Normally, as the minute ventilation (MV) increases, the PaCO2 should decrease. The normal pattern is an inverse relationship. In dead space, the alveolar ventilation decreases even as the respiratory rate increases. This results in an increase in CO2 and an abnormal relationship between MV and PaCO2. The patient has respiratory acidosis, not metabolic acidosis. It is not a normal blood gas for a patient with COPD because the pH is abnormal. There is no indication in this scenario that this would be an upper airway obstruction. What is the compensatory mechanism for VQ shunting? A. Decrease MV B. Bronchoconstriction C. Pulmonary vasoconstriction D. Increase cardiac output correct answers C VQ shunting is perfusion without ventilation. A compensatory mechanism for the VQ shunt is pulmonary vasoconstriction to redistribute blood flow to ventilated alveolar units. In VQ shunts, patients increase their respiratory rate, causing an increase in min- ute ventilation. Bronchoconstriction occurs with dead space in an attempt to shunt ven- tilation to perfused alveoli. An increase in cardiac output can occur in response to tissue hypoxia but is not considered a compensatory mechanism for a pulmonary shunt. Which of the following findings would indicate the presence of obstructive airway disease? A. FEV1/FVC ratio of 60% B. FEV1/FVC ratio 75% to 80% C. FEV1/FVC ratio 80% D. Normal FEV1/FVC ratio correct answers A An obstructive airway disease causes a decrease in FEV1 with a relatively normal FVC resulting in a decrease in the FEV1/FVC ratio. A normal ratio is 75% to 80%. The lower the ratio, the greater the obstruction of airflow. This test is used to assess asthma patients during bronchodilator treatments. A normal FEV1/FVC ratio would indicate a restrictive airway disease. A patient in the ICU is diagnosed with ARDS. The following are the ventilator settings and ABG results: