Comparison of four endotracheal tube cleaning protocols in anesthetized dogs.

OBJECTIVE: To compare the efficacy of 4 cleaning protocols applied to endotracheal tubes (ETTs) collected from anesthetized dogs. SAMPLE: 100 ETTs (25 per protocol). PROCEDURES: A 10-question survey designed to determine ETT reuse and cleaning practices was distributed via email to a sample of veterinary anesthesiologists. Informed by survey results, 4 ETT cleaning protocols were selected for use in a prospective clinical study. Dogs were intubated with sterile polyvinyl chloride ETTs. At extubation, each ETT was cultured for bacterial growth, randomly assigned to 1 of 4 protocols [water scrub (P1), detergent scrub (P2), detergent scrub and chlorhexidine gluconate (CHG) soak (P3), or detergent scrub and bleach soak (P4)], and cultured again after drying. Bacterial genera were identified using mass spectrometry and 16s rRNA sequencing. Proportions of ETTs exhibiting no post-cleaning growth were compared between protocols using the Fisher exact test with Bonferroni correction. RESULTS: Half of survey respondents that reused ETTs did not sterilize them before reuse, cleaning methods varied widely, and no reported methods were evidence-based. After use, the number of ETTs exhibiting no post-cleaning bacterial growth were 15/25 (60%), 14/25 (56%), 20/25 (80%), and 17/25 (68%) for protocols P1, P2, P3, and P4, respectively. Pairwise comparisons did not reveal any statistically significant differences between protocols. CLINICAL RELEVANCE: In small animal patients, some veterinary anesthesiologists reuse ETTs without sterilization and cleaning protocols vary widely. No differences between the studied protocols were identified. Further research is necessary to identify a safe, efficacious ETT cleaning protocol for use in small animal practice.

Arctic soil methane sink increases with drier conditions and higher ecosystem respiration.

Arctic wetlands are known methane (CH4) emitters but recent studies suggest that the Arctic CH4 sink strength may be underestimated. Here we explore the capacity of well-drained Arctic soils to consume atmospheric CH4 using >40,000 hourly flux observations and spatially distributed flux measurements from 4 sites and 14 surface types. While consumption of atmospheric CH4 occurred at all sites at rates of 0.092 ± 0.011 mgCH4 m-2 h-1 (mean ± s.e.), CH4 uptake displayed distinct diel and seasonal patterns reflecting ecosystem respiration. Combining in situ flux data with laboratory investigations and a machine learning approach, we find biotic drivers to be highly important. Soil moisture outweighed temperature as an abiotic control and higher CH4 uptake was linked to increased availability of labile carbon. Our findings imply that soil drying and enhanced nutrient supply will promote CH4 uptake by Arctic soils, providing a negative feedback to global climate change.