3.4. Topical (inhaled) antibiotics
Three retrospective cohort studies evaluated the use of nebulised antimicrobials in paediatric tracheostomy patients32–36. Of these studies, one assessed the use of prophylactic nebulised antimicrobials34,36, one nebulised antimicrobials in the context of LRTIs32,33and one reported possible safety concerns regarding the ongoing use of nebulised tobramycin in paediatric tracheostomy patients35.
A small retrospective cohort study of 22 tracheostomised children looked at the use of nebulised antimicrobials to manage persistent bacterial lower airway colonisation following LRTI according to the results of the tracheal aspirate cultures33. There was no control group and no standard antimicrobial regimen: 14 received gentamicin and 8 received colistin, median antibiotic duration was 3.5 months. Nebulised antimicrobials reduced median bacterial colony count at the 12th month after the start of the nebulised antimicrobials (105 colony-forming unit (CFU)/ml vs. 104 CFU/ml; p = 0.02). The median number of hospitalisations following treatment with nebulised antimicrobials decreased from 2 (range 1–3.5) to 1 (range 0–1.5) (p = 0.04). Additionally, duration of intensive care admissions reduced significantly from 89.5 days (range 43–82.5 days) to 25 days (range 7.75–62.75 days) after starting nebulised antimicrobials (p=0.028). Gentamicin resistance was noted during treatment in almost a third of patients (n=6).
Prophylactic inhaled antimicrobials have also shown some promise in a small retrospective case series of six tracheostomised children, which trialled the use of either inhaled colomycin or tobramycin for a median of 74 days (range 22-173 days)34. Although they reported a reduction in median days of systemic antimicrobial use (18 vs 2 days) and episodes of LRTI (2 vs 1 episode) in the 3-months pre-treatment versus 3-months post-treatment, neither finding was statistically significant.
Inhaled antimicrobials appear to have a good safety profile; however, Hughes et al. did highlight the need for caution in using inhaled tobramycin in paediatric patients with concomitant renal disease35. In their retrospective cohort of 12 tracheostomy-dependent paediatric patients, 11 had undetectable trough concentrations (defined as <0.6 mcg/mL), whilst one patient with known polycystic kidney disease had a steady-state trough concentration of 2.1 mcg/mL after only 5 doses of inhaled tobramycin.