A 47-year-old man is hospitalized due to worsening shortness of breath over the last 2 days. He complains of orthopnea requiring 2 pillows to sleep. The patient has a history of coronary artery disease and underwent coronary artery bypass grafting 2 years ago. He has been nonadherent with his medications.
His temperature is 98.6° F (37° C) , blood pressure is 157/90 mm Hg, pulse is 113/min, and respirations are 34/min. Pulse oximetry shows 88% on 100% O₂ non-rebreather face mask. He appears to be in respiratory distress and is using accessory muscles of respiration. Jugular venous pressure is estimated at 12 cm H₂O. Examination shows a third heart sound and bibasilar crackles. There is 1+ pitting peripheral edema bilaterally to the shins.
The patient's chest-x ray is shown below.

ECG shows sinus tachycardia with nonspecific T-wave changes.
Which of the following best describes how noninvasive positive pressure would benefit this patient?

Question

A 47-year-old man is hospitalized due to worsening shortness of breath over the last 2 days. He complains of orthopnea requiring 2 pillows to sleep. The patient has a history of coronary artery disease and underwent coronary artery bypass grafting 2 years ago. He has been nonadherent with his medications.
His temperature is 98.6° F (37° C) , blood pressure is 157/90 mm Hg, pulse is 113/min, and respirations are 34/min. Pulse oximetry shows 88% on 100% O₂ non-rebreather face mask. He appears to be in respiratory distress and is using accessory muscles of respiration. Jugular venous pressure is estimated at 12 cm H₂O. Examination shows a third heart sound and bibasilar crackles. There is 1+ pitting peripheral edema bilaterally to the shins.
The patient's chest-x ray is shown below.

ECG shows sinus tachycardia with nonspecific T-wave changes.
Which of the following best describes how noninvasive positive pressure would benefit this patient?

Quizplus · Accepted Answer

This patient has acute decompensated heart failure (ADHF), likely due to reduced left ventricular systolic function, as evidenced by cardiomegaly on imaging. The reduced cardiac output increases left ventricular filling pressures and left atrial pressure (increased preload). The elevated pressures are eventually transmitted to the pulmonary capillaries, leading to fluid transudation. Patients with cardiogenic pulmonary edema who continue to have respiratory distress, respiratory acidosis, and/or hypoxia while on a non-rebreather face mask delivering 100% oxygen should be placed on noninvasive positive-pressure ventilation (NPPV). NPPV in cardiogenic pulmonary edema patients decreases the need for intubation and enhances oxygenation via improvements in respiratory and cardiac parameters. noninvasive positive-pressure ventilation (NPPV) NPPV increases intrathoracic pressure; this results in reduced venous return, decreased right and left ventricular preload, and improved cardiac output (via the Frank-Starling relationship). NPPV also reduces LV afterload as the high intrathoracic pressure has a squeezing effect on the left ventricle, augmenting ventricular contraction. There is a subsequent reduction in the pressure gradient between the left ventricle and aorta, reducing the work (afterload) required for contraction (Choice D). NPPV augments inspiratory and expiratory flow, decreasing the work of breathing. Specifically, it unloads (and augments) the inspiratory muscles, increasing tidal volume and functional residual capacity (Choice A). Further, by re-expanding flooded alveoli, NPPV decreases dead space ventilation. There is a resultant reduction in the amount of ventilation/perfusion mismatch and improvements in alveolar (and therefore minute) ventilation (Choices B and E). Educational objective: Noninvasive positive-pressure ventilation in cardiogenic pulmonary edema patients enhances oxygenation via improvements in respiratory (↓dead space ventilation, ↑tidal volume, ↑alveolar/minute ventilation) and cardiac indices (↓preload, ↓afterload). __________ References: Noninvasive ventilation in acute cardiogenic pulmonary edema. (http://www.ncbi.nlm.nih.gov/pubmed/18614781)

A 47-Year-Old Man Is Hospitalized Due to Worsening Shortness of Breath