Antibiotic Use in Surgical Patients: Preventing SSI and Addressing Resistance, Esquemas y mapas conceptuales de Economía

¡Descarga Antibiotic Use in Surgical Patients: Preventing SSI and Addressing Resistance y más Esquemas y mapas conceptuales en PDF de Economía solo en Docsity! Ask the Expert Surgery Peer Reviewed Antibiotics in Surgical Patients Laurent Findji, DMV, MS, MRCVS, DECVS VRCC Veterinary Referrals Essex, United Kingdom You have asked… When should antibiotics be used to prevent surgical site infection (SSI)? The expert says… A ntibiotic use in surgical patients is aimed at preventing SSIs or treating known preexisting infections. In the latter case, antibiotic administration should follow general principles of appropriate antimicrobial therapy, which are beyond the scope of this article.1 Antibiotic use is not innocuous, despite minimal adverse effects. Inappropriate antibiotic use can result in a high risk for therapeutic failure and emerging bacterial resistance, affecting both the patient and its environment. Because bacterial resistance is a major public health concern, veteri- nary professionals need to demonstrate responsibility and dedication to avoid antibiotic misuse or face limitations and loss of privilege in prescribing these drugs. It is, therefore, each veterinari- an’s duty to critically review antibiotic use according to the best available evidence. Antibiotics & SSI Risks The preliminary step in judicious antibiotic administration is to understand what can be expected from their use. SSI development depends on several factors: the amount and nature (virulence) of bacterial contamination, local conditions (wound), and susceptibility of the host (patient). Thus, prevention of SSI must be seen as a chain of factors, including patient condition, surgical preparation, antimicrobial administration strategy, potential for contamination in the surgical environment, and wound condition (depends on the quality of surgical technique). The strength of this chain is limited by its weakest link. Increasing the antibiotics administered (ie, type, dose, duration) to patients involved in excessively traumatic surgical procedures or when poor aseptic technique has been used will not necessarily lower the SSI rates but can favor bacte- rial resistance and clinical adverse effects. Similarly, using antibiotics locally within the peritoneal Antibiotic use is not innocuous, despite minimal adverse effects. MORE SSI = surgical site infection May 2014 • Clinician’s Brief 19 Ask the Expert concentrations are decreased and surgeons must consider one additional antibiotic administration after fluid replacement.6 In prophylaxis, as no infection is present, the antibiotic must target the pathogens most likely to contaminate the wound. Antimicrobial therapy, meanwhile, refers to the treatment of an existing infection and consists of administering antibiotics tar- geted at the main infectious pathogens, until the infection is reduced enough to be eliminated by the host’s defenses. Typi- cally, antibiotics are given before, during, and for several days after surgery. For patients already on antibiotics, the necessity and timing of perioperative antibiotic administration must be determined on an individual basis: the sensitivity of expected pathogens to the antibiotic and its pharmacokinetics should be considered to ensure that effective concentrations are present in tissues before potential contamination. Current Recommendations Antibiotics do not only affect pathogens. Broad-spectrum anti- biotics can alter normal microbial flora in unpredictable ways, possibly promoting bacterial resistance in some of its compo- nents.7 To limit this adverse effect, narrow-spectrum (vs wide- spectrum) antibiotics are preferred when possible to limit resistance or development of resistance.7 Only first-generation, narrow-spectrum antibiotics active against the main SSI patho- gens in small animals (eg, Staphylococcus spp, Escherichia coli, Pasteurella spp) should be used, particularly for prophylaxis. Newer, broad-spectrum antibiotics (eg, fluoroquinolones) should be avoided for prophylaxis to reduce the emergence of resistant bacterial strains.8 Intraoperative wound contamination cannot be avoided. Two studies found that suction tips were contaminated in 44% and and thoracic cavities is not recommended, as these agents induce local inflammation and have not proven beneficial.2,3 Perioperative antibiotics are an adjunct to (ie, not a substitute for) proper surgical preparation and technique. Advanced sur- gical experience (implying lesser surgical trauma), may con- found the potential effect of antimicrobial prophylaxis.2,3 Unfortunately, antibiotics are often prescribed to compensate for insufficient surgical preparation or intraoperative care. Every effort should be made to strengthen all links of the chain equally. The surgeon must strictly adhere to the rules of asepsis and strive to minimize surgical trauma while implementing a sensible approach to antibiotic use. Antimicrobial Prophylaxis & Therapy Antimicrobial prophylaxis refers to the use of antibiotics to pre- vent an expected infection caused by contamination. For pro- phylaxis, appropriate antibiotic concentrations must be present in exposed tissues at contamination and for a few hours after, but not before or beyond contamination. Given the pharmaco- kinetics of most antibiotics, this means that they are best given intravenously within an hour before skin incision and repeated as necessary to maintain sufficient antibiotic levels in the tis- sues throughout the procedure and for a few hours following it. Studies have shown that administration of antibiotics after contamination (eg, after surgery) is ineffective and may even increase the risk for SSI.4,5 Typically, antibiotics are given at anesthetic induction (ie, ~30 minutes before incision) and readministered q90min during the procedure. When the surgery ends slightly before scheduled readministration, antibiotics should be administered as if the surgery was not finished. If orthopedic implants are used, pro- longing the series of administration for a few hours (≤24) after surgery is sometimes recommended. In case of massive fluid replacement for blood loss (≥20–25 mL/kg), antibiotic tissue Antimicrobial prophylaxis refers to prevention of an expected infection caused by contamination. Antimicrobial therapy refers to treatment of an existing infection. 20 cliniciansbrief.com • May 2014