In this episode I’ll:
1. Discuss an article about whether aspirin affects mortality in staph aureus bloodstream infection
2. Answer the drug information question “Why is phenylephrine such a bad vasopressor to use in sepsis?”
3. Share a resource for finding medical information on social media
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Lead author: Michael Osthoff
Published in Critical Care Medicine April 2016
Experimental and observational studies provide evidence of a direct antistaphylococcal effect of aspirin. Several studies have analyzed the association between aspirin use and outcomes in intensive care patients with systemic inflammatory response syndrome and the prevention of catheter associated S. aureus bloodstream infections.
The investigators’ goal was to estimate the effect of low-dose aspirin therapy on mortality in bloodstream infections caused by S. aureus compared with Escherichia coli. The study was a retrospective cohort study of 838 and 602 episodes of S. aureus and E. coli bloodstream infection in a Swiss tertiary referral center. Adult patients with S. aureus and E. coli bloodstream infection, respectively, were categorized according to low-dose aspirin therapy use and non-use before bacteremia.
S. aureus bloodstream infection cases and controls were equally matched for relevant confounders except treatment with statins, which was strongly associated with a low-dose aspirin use. At day 30, 12.1% of cases and 27.4% of controls had died. Low-dose aspirin use was associated with a reduced 30-day all-cause mortality in multivariate analysis of matched patients and also of the entire cohort after adjustment. In contrast, low-dose aspirin use was not associated with the primary endpoint in patients with E. coli bloodstream infection.
The authors concluded that low-dose aspirin at the time of bloodstream infection was strongly associated with a reduced short-term mortality in patients with S. aureus bloodstream infection. Future studies are required to investigate if early low-dose aspirin is a suitable treatment in patients with S. aureus bloodstream infection.
This retrospective study provides great evidence for the need to do a prospective evaluation of aspirin in S. aureus bloodstream infection. One important limitation of this study is that all patients in the aspirin use group were already on low-dose aspirin before the onset of S. aureus bloodstream infection. It is unknown whether treatment with low-dose aspirin after the onset of S. aureus bloodstream infection will affect mortality. The potential for non-antibiotics to have beneficial effects on mortality from S. aureus bloodstream infection is exciting, but I’ll need to see prospective data before using this in any of my patients.
Drug information question
Q: Why is phenylephrine such a bad vasopressor to use in sepsis?
A: The problem with phenylephrine is that it reduces venous return to the heart.
— Pharmacy Joe (@PharmacyJoe) February 17, 2016
I discussed vasopressors in more detail back in episode 5. Phenylephrine is a pure alpha agonist that Increases blood pressure by vasoconstriction. After a transient increase in preload, phenylephrine results in an increased venous resistance which decreases venous return to the heart. Decreased venous return is already a problem in septic patients, and phenylephrine can actually worsen the situation.
Twitter hashtags are a great way to filter pharmacy & medical discussion on twitter. Many experts are accessible on this platform and engage with those that interact with them. One of the nice things about Twitter is that you can watch the conversation without having to create a twitter account. One of my favorite hashtags to watch is the “#FOAMed” hashtag which stands for Free Open Access Medical education. To see the conversation taking place just go to twitter.com/hashtag/FOAMed. Whenever I am using social or non-traditional media for learning purposes, keep in mind that there is no editor guaranteeing the legitimacy of the content you find. The onus is yours to determine whether the source is credible.
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.