Welcome to PICU Doc On Call, a podcast dedicated to current and aspiring intensivists. My name is Pradip Kamat
and my name is Rahul Damania and we come to you from Children's Healthcare of Atlanta Emory University School of Medicine. Today's episode is dedicated to the rational use of antibiotics in the PICU
We are delighted to be joined by two brilliant Pediatric clinical pharmacists Ms Whitney Moore and Ms. Stephanie Yasechko from Children's Healthcare of Atlanta.
I will turn it over to Rahul to start with our patient case...
Case

An 8-year-old female (24 kg, 130 cm) with PMH significant for severe persistent asthma and history of multiple PICU admissions presents to the ED with swelling, redness and inability to bear weight in her (L) lower leg.
Patient had just finished soccer practice the evening prior to her ED visit when she first noticed swelling and redness of her left lower leg. She also had a fever as well as some non-bloody, non-bilious emesis. Her past h/o is significant for poorly controlled asthma with multiple admissions to the PICU.
Upon arrival to the ED, patient's BP was hypotensive, tachycardic, and tachypneic. She was given two 20 mL/kg NS boluses, and blood cultures were drawn in addition to a CBC, BMP, and UA.
Labs were notable for an elevated white count, lactate, and serum Cr. Patient was given a dose of antibiotic, and transported to the PICU for further workup and management.
Whitney and Stephanie welcome to PICU Doc on call.
Thanks Rahul and Pradip for having us. Neither one of us have any financial disclosures or conflicts of interest.
We want to divide today's discussion into 3 segments- antibiotic selection, transition into dosing and end with therapeutic monitoring
Whitney, what are some of the factors to consider prior to choosing an antibiotic regimen in our patient case with a preliminary diagnosis of cellulitis of the left lower extremity with possible sepsis?
Whitney: First and foremost you want to consider your host so really diving deep into the patient’s past medical history and secondly we should consider the likely pathogens that are causing the patient’s infection. In this case given the invasive nature of her infection and recent hospital admissions I would start Vancomycin and Cefepime. Once blood cultures results are back, we can then tailor or narrow her antibiotics based on susceptibilities.

Stephanie what are some of the other factors to consider prior to starting antibiotics in this patient?
Other things to consider include her multiple previous hospitalizations, significant exposure to broad-spectrum antibiotics, whether or not she is immunocompromised, the presence of chronic conditions like lung disease, ventilator/trach dependency, and if patient was a resident of a long term care facility. Additionally any history of organ or bone marrow transplant or malignancy with use of chemotherapy/radiation, and/or a history of growth of multiple drug resistant organisms.

This is an important point - infectious disease is not just about the relevant pathogen or "bug" but it is also about understanding the host status!
Stephanie -why vancomycin and cefepime in this case?
In this patient the major pathogens to consider include: P. aeruginosa (give her multiple previous PICU admissions).
Also she has extensive cellulitis which necessitates antibiotic coverage against Methicillin resistant staph aureus (MRSA) and Streptococcus pyogenes . So our options in this case include vancomycin for broad-spectrum gram positive coverage, and generally either piperacillin/tazobactam or cefepime for broad-spectrum gram negative and pseudomonal coverage.
As you can see by patient’s Scr, it appears that she is presenting in AKI since we have no history of her having any type of renal impairment at baseline; therefore, to minimize additional AKI risk, cefepime would be our most appropriate choice for the time being. There is literature that shows us that the combination of...