Septic shock in patients with high-severity HAP
For patients with high-severity HAP who have septic shock, consider adding vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) and an aminoglycoside for resistant gram-negative bacteria.
The choice of aminoglycoside may be influenced by several factors, including:
- the spectrum of activity
- the availability of aminoglycoside therapeutic drug monitoring
- whether the laboratory reports aminoglycoside susceptibility
- drug cost.
There are limited clinical data to support tobramycin over gentamicin; however, the minimum inhibitory concentration (MIC) for tobramycin is slightly lower than gentamicin in vitro (particularly for P. aeruginosa) and has a greater likelihood of target attainment.
Generally, either gentamicin or tobramycin can be used in patients with high-severity HAP who have septic shock but, in some patients, one aminoglycoside may be preferred to another:
- For patients with chronic suppurative lung disease (eg bronchiectasis) who have known respiratory colonisation with P. aeruginosa, tobramycin is preferred to gentamicin.
- For patients in whom infection with P. aeruginosa is considered likely, tobramycin is preferred to gentamicin.
- For all other patients, either gentamicin or tobramycin is usually preferred to amikacin. However, the antibiotic susceptibility of resistant gram-negative bacteria varies. When choosing an aminoglycoside, consider local epidemiology and whether the patient has risk factors for infection with a multidrug-resistant gram-negative bacterium. Also consider whether there is a risk of infection with a pathogen resistant to aminoglycosides – seek expert advice to guide antimicrobial choice but do not delay administration of an aminoglycoside in the interim. For amikacin dosing, see Amikacin initial dose calculator for adults or Initial aminoglycoside dosage for treating infection in children 1 month to younger than 18 years for children.
Consider adding an aminoglycoside (gentamicin or tobramycin) plus vancomycin to the empirical therapy regimen for high-severity HAP. In adults and children, use:
1gentamicin intravenously; see Principles of aminoglycoside use for prescribing considerations and subsequent dosing gentamicin gentamicin gentamicin
adult: see Gentamicin initial dose calculator for adults for initial dose
child younger than 18 years: 7 mg/kg as an initial dose1
OR
1tobramycin intravenously; see Principles of aminoglycoside use for prescribing considerations and subsequent dosing tobramycin tobramycin tobramycin
adult: see Tobramycin initial dose calculator for adults for initial dose
child younger than 18 years: 7 mg/kg as an initial dose1
PLUS with either of the above regimens
vancomycin intravenously vancomycin vancomycin vancomycin
adult: 25 mg/kg (actual body weight) rounded up to nearest 125 mg, up to 3 g, as a loading dose. See Calculated vancomycin loading dosage in critically ill adults for calculated weight-based loading doses. Subsequent doses are dependent on weight and kidney function; see Intermittent vancomycin dosing for critically ill adults
child: for initial dosing, see Intermittent vancomycin dosing for young infants and children.
Review therapy at 24 to 48 hours. Consider stopping the aminoglycoside or vancomycin based on the results of investigations – see Review of patients with high-severity HAP.