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C-Reactive Protein (CRP) Protocol for the Guidance of Antibiotic Therapy in the NICU Based on the current recommendations to treat stable NICU patients with antibiotics for 48-72 hours with negative blood culture results and 7-14 days for blood-culture positive or clinical probable infection, up to 30 uninfected babies are treated for every infected baby. Potential adverse effects of unnecessary antibiotic usage include short-term (e.g. pain, infection, infiltration) and long-term complications (e.g. NEC, hearing, resistance development). Several studies suggest that serial CRP values (in combination with CBC) may be a useful tool to help the experienced clinician in decision making regarding initiation and duration of antibiotics in stable NICU patients. Using a clinical pathway for neonatal sepsis, which is based primarily on CRP determinations, can minimize antibiotic exposure and shorten hospital stays in term infants. However, there is not an established standard of practice for the use of CRP in VLBW infants. CRP is a nonspecific, acute-phase reactant that is synthesized in hepatocytes under influence of mediators (e.g. IL-6). CRP plays a role in innate immunity and in lipid metabolism. Secretion starts within 4-6 h after stimulation and peaks after 36h. The biological half-time is 19h, 50% reduction/day when acute-phase stimulus resolves. CRP is measured at Vanderbilt by rate nephelometry in the Toxicology laboratory. Approved sources are plasma or serum (approx. 500 μl). CRP is available “24/7” including holidays and the turn-around is approximately 40 min. CRP can be obtained from cord blood since it does not cross the placenta. Maximum cytokine and CRP responses may be lower in preterm compared to term infants, but same cut-off values apply (<10 mg/L). Two CRP levels <10 mg/L obtained 24h apart, 8-48h after presentation, make sepsis unlikely. Best sensitivity can be achieved after three CRP levels <10 mg/L. CRP levels can be influenced by mode of delivery (lowest after c-section, highest after vacuum extraction), days after birth (baseline CRP peaks at 48h of life), type of organism (lower levels with CONS), numerous other factors (increase after surgery / tissue damage / viral illness). Important to know is that CRP levels may not be elevated in overwhelming sepsis with granulocytopenia! The algorithm below helps in guidance of CRP usage. Please remember: It may be harmful to withhold antibiotics based on negative laboratory results if used as the only sign. Clinical experience is still required for making the “right” decision. Using CRP for Early Onset Neonatal Infections Using CRP for Late Onset Neonatal Infections
Literature: 1. Hengst, Advances in Neonatal Care, 2003 2. Ishibashi et al., Clinical Chemistry, 2002 3. Philip & Mills, Pediatrics, 2000 4. Benitz et al., Pediatrics, 1998 5. Franz et al. Pediatrics, 1999 6. Franz et al. Pediatrics, 2000 Last updated 3-2005 Weitkamp/Hamdan/Walsh |