In this episode I’ll:
1. Discuss an article about antibiotic stewardship in aspiration pneumonia.
2. Answer the drug information question “How long will urine stay green after a patient receives methylene blue?”
3. Share a resource on critical care toxicology.
Article
Lead author: Jean Baptiste Lascarrou
Published in Critical Care Medicine August 2017
Background
Empiric antibiotics for aspiration pneumonia are frequently given. However many aspiration events result not in infection but in pneumonitis. Previous pneumonia guidelines have been largely silent on the issue of when to use and when to withhold antibiotics for aspiration pneumonia.
Methods
The authors conducted a prospective observational study to determine the proportion of patients with microbiologically documented bacterial aspiration pneumonia. 250 comatose, ventilated patients were included. Patients with aspiration syndrome underwent telescopic plugged catheter sampling during bronchoscopy before starting antibiotic treatment. Antibiotics were stopped when cultures were negative.
Results
92 patients had aspiration syndrome, and 43 of these patients had bacterial aspiration pneumonia. Of the 49 patients with negative cultures, 33 had antibiotics stopped, and 16 had antibiotics continued for other infections. Of the 33 patients who had antibiotics stopped, only 2 went on to show signs of lung infection. Outcomes such as mortality, mechanical ventilation duration, and ICU length of stay did not differ between the patients with bacterial aspiration pneumonia and the patients with negative cultures.
Conclusion
The authors concluded:
Among comatose patients receiving mechanical ventilation, those without clinical, laboratory, or radiologic evidence of bacterial aspiration pneumonia did not require antibiotics. In those with suspected bacterial aspiration pneumonia, stopping empirical antibiotic therapy when routine telescopic plugged catheter sampling recovered no microorganisms was nearly always effective. This strategy may be a valid alternative to routine full-course antibiotic therapy. Only half the patients with suspected bacterial aspiration pneumonia had this diagnosis confirmed by telescopic plugged catheter sampling.
Discussion
This is a key study for pharmacists interested in antimicrobial stewardship because current pneumonia guidelines do not strongly address the problem of over use of antibiotics in aspiration pneumonia. Often, aspiration pneumonia is noninfectious, and this study represents a method that worked in a single center to differentiate aspiration pneumonia from pneumonitis and d/c antibiotics before a full course of therapy is given.
Drug information question
Q: How long will urine stay green after a patient receives methylene blue?
A: Possibly beyond 24 hours.
Methylene blue’s metabolite leucomethylene blue is excreted primarily in the urine. It combines with yellow pigment in urine to form green urine. In a patient with normal renal function, urine may remain green for as little as 10 hours after receiving methylene blue. However, in patients with impaired renal function green urine may persist after 24 hours.
Resource
The resource for this episode is the second edition of Critical Care Toxicology. This book provides a fully comprehensive resource for managing the post emergency/treatment stage of acute poisoning. Chapters incorporate evidence-based paradigms with up-to-date citations from the original medical literature. Topic areas covered include diagnosis and management of the critically poisoned patient, including pediatric patients and poisoning in pregnancy; toxic syndromes including hepatotoxic and pulmonary syndromes as well as poisonings from medications, drugs of abuse, chemical and biological agents.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
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