A 38-year-old woman in the intensive care unit is evaluated for worsening hypoxia. The patient was admitted a week ago due to dyspnea and nonproductive cough. At that time, diffuse crackles were found on lung examination, and chest x-ray revealed bilateral infiltrates. The patient smoked crack cocaine and used intravenous heroin prior to symptom onset. She required endotracheal intubation due to hypoxic respiratory failure and has been mechanically ventilated. Her respiratory condition has gradually improved over the past week, but in the last 2 days she has required a higher fraction of inspired oxygen. The patient has also had increased tracheobronchial secretions. Temperature is 38.9 C (102 F), blood pressure is 112/71 mm Hg, pulse is 114/min, and respirations are 22/min. Central venous pressure is 8 cm H₂O. Lung auscultation reveals bilateral crackles. Heart sounds are normal with no murmur or gallop. The abdomen is soft and nondistended with normoactive bowel sounds. She has no dependent edema or skin rash. Ventilator settings, arterial blood gases, and laboratory results are as follows: Repeat chest x-ray reveals asymmetric worsening of the lung infiltrate. Which of the following is the best next step in management of this patient?

Question

Quizplus · Accepted Answer

Explanation: 11ec2b69_c07e_5d53_8f63_57d3642203b7_MD0005_00 This patient initially had acute respiratory distress syndrome (ARDS), likely due to crack cocaine inhalation. The new onset of fever, increased secretions, worsening pulmonary infiltrates, and increased requirement for ventilatory support are consistent with ventilator-associated pneumonia (VAP), a common complication of ARDS. VAP can develop after ≥48 hours of mechanical ventilation and is most commonly caused by microaspiration of virulent oropharyngeal organisms (eg, Escherichia coli, Streptococcus species). Other signs of VAP include leukocytosis, tachypnea, and decreased oxygenation. Due to the nonspecific nature of its presentation and the increasing prevalence of drug-resistant organisms, respiratory sampling is necessary to confirm the diagnosis and appropriately tailor antibiotic therapy. Options include bronchoalveolar lavage or tracheobronchial aspiration. Once sampling has been performed, empiric antibiotics can be initiated while awaiting culture data. The specific regimen depends on individual risk factors for multidrug-resistant organisms and typically includes gram-positive and gram-negative coverage. Patients with risk factors for resistant pathogens should receive coverage for methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. (Choice A) CT pulmonary angiography would be the next step to diagnose acute pulmonary embolism, which more commonly presents with tachycardia, tachypnea, and hypoxia. However, this patient's high fever, leukocytosis, increased tracheobronchial secretions, and worsening pulmonary infiltrates are better explained by VAP. (Choice B) Although negative fluid balance is associated with improved mortality in ARDS, the current decompensation is consistent with sepsis due to VAP, for which diuresis with furosemide is relatively contraindicated. Moreover, this patient does not have elevated central venous pressure, extra heart sounds, or dependent edema, making volume overload unlikely. (Choice C) Mechanical ventilation with patients in prone position may have mortality benefits in severe ARDS, likely due to enhanced gas exchange (through improvements in lung perfusion and transpulmonary pressure differences). However, it is generally reserved for those in whom ventilator settings have been maximized (eg, fraction of inspired oxygen of 100%) and is associated with complications (eg, nerve compression, tube dislodgment). (Choice D) Systemic corticosteroids for the treatment of ARDS remain controversial, but they have no role in the treatment of VAP. Educational objective: Ventilator-associated pneumonia is associated with fever, increased secretions, worsening pulmonary infiltrates, and increased requirements for ventilatory support occurring ≥48 hours after mechanical ventilation. Respiratory sampling is necessary to confirm the diagnosis and appropriately tailor an antibiotic regimen. References: Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society. (http://www.ncbi.nlm.nih.gov/pubmed/27418577) Ventilator-associated pneumonia. (http://www.ncbi.nlm.nih.gov/pubmed/25279009)

A 38-Year-Old Woman in the Intensive Care Unit Is Evaluated