Acute respiratory distress syndrome Flashcards
A 50-year-old woman with no significant medical history is 2-days postoperative after an extensive exploratory laparotomy, a total abdominal hysterectomy and bilateral salpingo-oophorectomy, and an optimal tumor debulking for advanced ovarian carcinoma. You are called to her room because of new onset hypotension, tachycardia, tachypnea, fever (38.9°C or 101.2°F), and an oxygen saturation of 70%. on physical examination, she is alert, oriented, and anxious. The only physical finding is bilateral rales. Her oxygen saturation does not improve with supplemental oxygen. Her arterial blood gas is remarkable for a partial pressure of arterial oxygen (Pao2) of 50 mm Hg. A spiral computed tomography scan does not demonstrate an obvious segmental defect. A chest X-ray is remarkable for diffuse bilateral patchy infiltrates, normal cardiac silhouette, and no evidence of pleural effusions. The most appropriate next step in her management is
(A) an intravenous diuretic (B) mechanical ventilation (C) empiric anticoagulation (D) pulmonary artery catheter (E) broad-spectrum antibiotics
(B) mechanical ventilation
What are the clinical features of acute respiratory distress syndrome?
- CXR with bilateral, diffuse infiltrates
- Ratio of partial pressure of arterial oxygen to fraction of inspired oxygen 200 mmHg or less, regardless of level of positive end expiratory pressure
- Pulmonary capillary wedge pressure <18 mm Hg when no clinical evidence of L heart failure
- Acute onset
What is thought to be the pathophysiology of ARDS development?
Secondary outcome of a systemic inflammatory response: get an inflammatory lung injury (multiple pro-inflammatory cytokines, neutrophil activation) –> diffuse alveolar damage –> accumulation of interstitial and alveolar fluid causing altered gas exchange, increased pulmonary arterial pressure, and reduced pulmonary compliance
What are some of the common predisposing etiologies for ARDS development?
Sepsis, aspiration, pneumonia, trauma, multiple blood transfusions
How does ARDS present clinically?
Starts with pulmonary dysfunction 24-48h after the precipitating event: tachycardia, tachypnea, dyspnea, significant hypoxemia
Labs: ABG often shows an alveolar-arterial gradient and severe hypoxemia
Imaging: CXR shows diffuse, fluffy alveolar infiltrates
How is ARDS treated?
Supportive measures to maintain oxygenation, reduce interstitial fluid, prevent futher injury –> MECHANICAL VENTILATION (try to use lower tidal volumes 6-10 ml/kg, PEEP, lowest inspired fraction of O2 to limit iatrogenic injury)
Try to be conservative with fluid management due to increased pulmonary edema
