TABLE 62-1 Important Considerations of Selected Antimicrobial Agents | ||||||||||||||||||||||||
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The Use of Antimicrobials in the Treatment of Infection in the Critically III Patient
The Use of Antimicrobials in the Treatment of Infection in the Critically III Patient
Wayra Salazar-Moreno
David M. Bebinger
I. GENERAL PRINCIPLES
A. Make all reasonable attempts to arrive at a diagnosis for the syndrome encountered.
1. Clinical outcomes improve with targeted treatment for an accurate diagnosis.
2. Use clinical signs and symptoms to develop a differential diagnosis and predict morbidity.
3. Pursue diagnostic studies until an accurate diagnosis is identified.
B. Develop an empiric antimicrobial regimen based upon the differential diagnosis and predicted morbidity.
1. Isolated fever does not require empiric antimicrobial therapy. Patients with vital sign abnormalities have systemic inflammatory response syndrome (SIRS), which can be due to infectious or noninfectious etiologies.
2. Immunocompromised patients and those with signs of vascular collapse or organ dysfunction generally require empiric antimicrobial therapy.
3. Source control is required for optimal care.
a. Remove infected catheters and other nonessential foreign bodies.
b. Drain infected collections (e.g., empyema).
4. Promptly treat patients with sepsis and organ dysfunction with broadspectrum antibiotics.
a. All patients at risk for Staphylococcus aureus disease should be treated empirically for methicillin-resistant Staphylococcus aureus (MRSA).
b. Antimicrobials directed against gram-negative organisms depend on the clinical setting where the infection was acquired, the anatomic site of infection, and local susceptibility patterns (i.e., your hospital antibiogram).
c. Syndromes with an identified source should prompt antibiotic treatment directed at likely pathogens causing the specific type of infection.
C. Dose antimicrobials properly to ensure adequate levels and minimize toxicity.
1. The initial dose should be adequate to reach therapeutic levels quickly, rarely requires dose modification for organ dysfunction, and may need to be increased in septic shock.
2. Modification of subsequent doses may be required in patients with renal or hepatic dysfunction depending on the antimicrobial used.
3. Prescribe with attention to other medications being administered as many antimicrobials have drug-drug interactions.
D. Address dose/duration of therapy on a daily if not a shift-by-shift basis.
1. Discontinue antimicrobials if a noninfectious etiology explains the encountered syndrome.
2. Narrow antimicrobials when a specific organism is isolated and when sensitivity test results become available.
3. Adjust dose as needed when renal or hepatic function changes.
4. Determine the duration of therapy according to established standards.
5. Always discontinue nonessential antimicrobials to prevent toxicity and drug resistance.
II. ETIOLOGY/DIAGNOSIS/TREATMENT
A. Table 62-1 lists commonly used antimicrobials in the ICU setting along with some of their important characteristics.
B. Table 62-2 contains many of the commonly encountered infectious agents in the ICU setting and their preferred drug regimen(s).
