Silver-Coated Endotracheal Tubes Cleaned With a Mechanism for Secretion Removal

Abstract

Background: Biofilm on the surface of endotracheal tubes (ETTs) is associated with ventilator-associated pneumonia. The use of silver-coated ETTs has been suggested to reduce the occurrence of ventilator-associated pneumonia by preventing biofilm formation. However, mucus accumulation can reduce the antibacterial activity of silver-coated ETTs by isolating bacterial colonies from the silver surface. We hypothesized that, in mechanically ventilated subjects, periodic removal of secretions through the use of a cleaning device would enhance the antimicrobial properties of silver-coated ETTs and thus reduce bacterial colonization.

Methods: Subjects were randomized to either standard suctioning (blind tracheal suctioning, control group) or blind tracheal suctioning plus cleaning maneuver every 8 h (treatment group). Tracheal aspirates were collected immediately before extubation for microbiological culture. After extubation, ETTs were collected for both cultural and non-cultural microbiological analysis and biofilm isolation.

Results: 39 subjects expected to be ventilated for > 48 h were enrolled; 36 ETTs (18 control, 18 treatment) and 29 tracheal samples (15 control, 14 treatment) were collected. Among the ETTs positive for bacterial colonization (15 vs 9, P = .18), cleaning maneuvers did not reduce microbial load, shown as the decimal logarithm of colony-forming units (CFU) per mL (1.6 ± 1.2 vs 0.9 ± 1.2 logCFU/mL, P = .15). There was a trend toward decreased biofilm deposition (439.5 ± 29.0 vs 288.9 ± 157.7 mg, P = .09) in the treated ETTs. No significant differences were observed in the number of positive tracheal aspirates (13 vs 10, P = .39) or in the microbial load (4.8 ± 4.0 vs 4.2 ± 3.8 logCFU/mL, P = .70) of tracheal secretions. Finally, no differences in the microbial load of Gram-positive organisms, Gram-negative organisms, or yeasts were found between the ETTs and tracheal aspirates of the 2 groups.

Conclusions: In 39 critically-ill subjects intubated with silver-coated ETTs, periodic cleaning maneuvers did not decrease bacterial colonization of the ETTs and did not lower respiratory tract colonization compared to the standard suctioning. (Clinicaltrials.gov registration NCT02120001.).

Keywords: airway management; airway obstruction; biofilms; intubation; pneumonia; ventilation; ventilator-associated pneumonia.

Fig. 1.

Flow chart. ETT = endotracheal tube; CLSM = confocal laser scanning microscopy; FISH = fluorescent in-situ hybridization. * Subject was reintubated in the ICU and completed the study twice; for this subject 2 ETTs were collected.

Fig. 2.

Rates of (A) endotracheal tubes (ETTs) or (B) tracheal sputum microbial colonization by a single versus multiple species.

Fig. 3.

Samples 31 and 32 are from ETTs from the control group. Sample 31 shows Candida glabrata (green) and Staphylococcus spp. (red). Sample 32 shows yeast (green) and Staphylococcus spp. (red). Samples 33 and 41 are from ETTs from the treatment group cleaned with the endOclear device. Sample 33 shows C. glabrata (green) and Staphylococcus spp. (red). Sample 41 shows C. glabrata (green) and Klebsiella pneumoniae (red).