A 58-year-old man with a history of chronic obstructive pulmonary disease develops acute respiratory distress syndrome secondary to community-acquired pneumonia. He has been stable on mechanical ventilation with peak and plateau pressures

Question

A 58-year-old man with a history of chronic obstructive pulmonary disease develops acute respiratory distress syndrome secondary to community-acquired pneumonia. He has been stable on mechanical ventilation with peak and plateau pressures <30 cm H₂O, and his oxygen requirements have decreased over the past 2 days.
On his third day in the intensive care unit, he is ventilated on assist control mode, with a respiratory rate of 16/min, positive end-expiratory pressure of 10 cm H₂O, and FiO₂ of 0.6 (60%) . The patient's peak pressure ventilator alarm has been on for the past 10 minutes and his respirations appear more labored. Pulse has increased from 85 to 120/min, and respiratory rate has increased from 16 to 32/min. The peak pressure is 44 cm H₂O and the plateau pressure is 24 cm H₂O. On chest auscultation, breath sounds are coarse and mildly decreased on the left side.
Which of the following actions would be most likely to improve the patient's current symptoms?

Quizplus · Accepted Answer

11ec193a_971d_4ca2_853d_556d244e9a90_MD0002_00 Measurement of airway pressures can be useful in the management of mechanically ventilated patients: The peak airway pressure is the maximum pressure measured as the tidal volume is being delivered. It equals the sum of the resistive pressure (flow × resistance) and the plateau pressure. (Peak airway pressure = resistive pressure + plateau pressure). Peak pressures are dynamic pressures that measure the resistance to flow of air delivered from the ventilator and the amount of pressure needed to inflate the lung. Peak airway pressure is ideally maintained ≤35 cm H₂O to minimize risk of barotrauma.The plateau pressure is the pressure measured during an inspiratory hold maneuver, when pulmonary airflow and therefore resistive pressure are both 0. It equals the sum of the elastic pressure (elastance × tidal volume) and positive end-expiratory pressure. (Plateau pressure = elastic pressure + positive end-expiratory pressure). Plateau pressures are static lung pressures that give an estimate of lung compliance; a typical goal is ≤30 cm H₂O. Because elastance and compliance are inversely related, decreased compliance (eg, pulmonary fibrosis) causes stiffer lungs and higher elastic pressure. The peak airway pressure is the maximum pressure measured as the tidal volume is being delivered. It equals the sum of the resistive pressure (flow × resistance) and the plateau pressure. (Peak airway pressure = resistive pressure + plateau pressure). Peak pressures are dynamic pressures that measure the resistance to flow of air delivered from the ventilator and the amount of pressure needed to inflate the lung. Peak airway pressure is ideally maintained ≤35 cm H₂O to minimize risk of barotrauma. The peak airway pressure is the maximum pressure measured as the tidal volume is being delivered. It equals the sum of the resistive pressure (flow × resistance) and the plateau pressure. (Peak airway pressure = resistive pressure + plateau pressure). Peak pressures are dynamic pressures that measure the resistance to flow of air delivered from the ventilator and the amount of pressure needed to inflate the lung. Peak airway pressure is ideally maintained ≤35 cm H₂O to minimize risk of barotrauma. The plateau pressure is the pressure measured during an inspiratory hold maneuver, when pulmonary airflow and therefore resistive pressure are both 0. It equals the sum of the elastic pressure (elastance × tidal volume) and positive end-expiratory pressure. (Plateau pressure = elastic pressure + positive end-expiratory pressure). Plateau pressures are static lung pressures that give an estimate of lung compliance; a typical goal is ≤30 cm H₂O. Because elastance and compliance are inversely related, decreased compliance (eg, pulmonary fibrosis) causes stiffer lungs and higher elastic pressure. The plateau pressure is the pressure measured during an inspiratory hold maneuver, when pulmonary airflow and therefore resistive pressure are both 0. It equals the sum of the elastic pressure (elastance × tidal volume) and positive end-expiratory pressure. (Plateau pressure = elastic pressure + positive end-expiratory pressure). Plateau pressures are static lung pressures that give an estimate of lung compliance; a typical goal is ≤30 cm H₂O. Because elastance and compliance are inversely related, decreased compliance (eg, pulmonary fibrosis) causes stiffer lungs and higher elastic pressure. Increased peak pressure associated with an unchanged plateau pressure, as seen in this patient, suggests a pathologic process causing increased airway resistance without a change in lung compliance. The most likely cause of increased resistance to flow in this patient is a mucus plug, which may be improved with airway or endotracheal tube suctioning. (Choices B and C) Bronchospasm and the patient biting on the endotracheal tube are other causes of elevated peak pressures without an increase in plateau pressures. However, bronchospasm is expected to cause wheezing on examination. Increasing the sedation can help prevent biting of the endotracheal tube, but a mucus plug is more likely in this patient with unilateral decreased breath sounds and evidence of respiratory distress (eg, tachypnea). (Choices D and E) Intravenous furosemide and needle decompression of the left chest are treatments for pulmonary edema and tension pneumothorax, respectively. These conditions lead to decreased pulmonary compliance and would be suggested by an elevation in both plateau and peak airway pressures. Educational objective: Peak and plateau pressures are derived from the ventilator according to the different clinical states of the airway, lung, and chest wall. Peak pressures, also known as dynamic pressures, measure the resistance to flow of air delivered from the ventilator and the amount of pressure needed to inflate the lung. Plateau pressures are static lung pressures, measured during an inspiratory hold, that give an estimate of lung compliance. __________ References: Mechanical ventilation. (http://www.ncbi.nlm.nih.gov/pubmed/18655948)

A 58-Year-Old Man with a History of Chronic Obstructive Pulmonary