Tag Archives: antibiotics

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SCIP: Importance Of Prophylactic Antibiotics In Trauma Laparotomy

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Quite a lot of research has been done on the efficacy of prophylactic antibiotics in the prevention of infectious complications after surgical procedures. Antibiotics are now routinely given prior to most elective surgical procedures. In the US, the Centers for Medicare and Medicaid Services has formalized this into part of the Surgical Care Improvement Project (SCIP), which mandates the use of an appropriate antibiotic within 1 hour preop and stopping it within 24 hours postop.

But what about emergent cases, like trauma laparotomy? Ensuring timely antibiotic administration is difficult due to the rapid events leading up to the operation. And sometimes it is not clear whether a hollow viscus injury has occurred until after start of operation, so the antibiotic choice may change in the middle of the case.

Two busy urban trauma centers with high penetrating injury rates looked at one year of experience in patients undergoing trauma laparotomy. They compared surgical site infections (SSI) in patients who received SCIP-compliant antibiotic administration vs those who did not. 

Key findings:

  • Patient mix was 30% blunt, 44% gunshot, 27% stab wounds
  • There were 151 SCIP-compliant patients and 155 noncompliant ones
  • Half of the noncompliant group did not receive the appropriate antibiotic (usually Cefazolin in hollow viscus injury), and half had antibiotics given for more than 24 hours
  • SCIP-compliant patients had significantly fewer wound infections and shorter length of stay. Mortality was the same.

Bottom line: I recommend adhering to SCIP prophylactic antibiotic guidelines for trauma laparotomy. There is no reason why this subset of patients should be treated any differently, and this study presents evidence that it is beneficial. Using the SCIP guidelines in emergent surgery reinforces the usual preop routine in hospitals that have already embraced them. In general, blunt trauma patients undergoing laparotomy should receive prophylaxis that covers skin organisms. Since penetrating trauma has a much higher chance of involving the intestinal tract, broader spectrum antibiotics should be selected. In either case, use the antibiotic that has been selected for this purpose by your hospital. And be sure they are stopped during the first 24 hours.

Reference: “SCIP"ping antibiotic prophylaxis guidelines in trauma: the consequences of noncompliance. J Trauma 73(2):452-456, 2012.

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Antibiotics For Ventriculostomy

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There is some variability in how neurosurgeons manage ventriculostomy when it comes to antibiotic coverage. The catheter can become a conduit for bacterial infections of the meninges or brain, which can be life threatening. Most neurosurgeons will begin coverage at the time of catheter insertion, but the duration of treatment varies. What is the right answer, if any?

As is typical with most things related to head trauma, there are not a lot of good studies out there. Columbia University published a fairly comprehensive review of previous studies last year to help clarify this issue. They applied rigorous criteria to identify 10 relevant studies (3 randomized clinical trials and 7 observational studies) out of a pool of 347. Yes folks, this gives you an idea of how tough it is to answer good clinical questions from the stuff that gets published.

The study found that the use of either prophylactic antibiotics or antibiotic-coated external ventricular drains (EVD) decreased the number of infections by 68%. This result was consistent across both study designs. The authors could not show that one mode of antibiotic administration (systemic vs catheter coating) was better than the other. About half of the studies used antibiotics for the duration of the catheter; the other half did not specify.

Bottom line: Head injury patients with an EVD should receive antibiotics, either systemically or as a coating on the EVD catheter itself. Although not entirely clear, they should probably be given for the entire time the catheter is in place. Judgment must be used if this will be a long time, because there may be other adverse effects from giving long term antibiotics.

Reference: Prevention of Ventriculostomy-Related Infections With Prophylactic Antibiotics and Antibiotic-Coated External Ventricular Drains: A Systematic Review. Neurosurgery 68(4):996-1005, 2011.

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A New Method For Killing Antibiotic Resistant Bacteria

IBM and the Institute for Bioengineering and Nanotechnology have developed a novel way of wiping out antibiotic resistant bacteria like MRSA. They created a type of nanoparticle that is activated by contact with water. When this occurs, it self-assembles into a new polymer structure that is attracted to infected cells and bacteria, but not healthy cells.

Changes in electrostatic charge on the cell surface attracts the nanoparticles, which then physically break through the cell walls and membranes of bacteria. The nanoparticles then degrade and are excreted.

Bottom line: This is a very exciting line of research. Bacteria multiply and evolve rapidly, sharing genetic information that allows them to change their biochemistry and become resistant to our usual antibiotics. Since the destructive process used by these nanoparticles is purely physical and not biochemical, it will be extremely difficult for any type of resistance to develop. This is an important advance in our efforts to control pathogens.

Reference: Biodegradable nanostructures with selective lysis of microbial membranes. Nature Chemistry, April 3, 2011 (online).