de Groot, W. | Search bioRxiv

bioRxiv2024

Using breathing systems in anaesthesia for up to 7 days instead of 24 hours: a comparative microbial safety study

SummaryThe replacement frequency of mechanical ventilators breathing systems used in operating rooms (ORs) currently varies between hospitals. In light of evidence-based decision-making and sustainability efforts, we aim to determine whether 7-day use of breathing systems instead of 24 hours is microbial safe. In this prospective single-centre explorative study, 30mm UniflowTM breathing systems used in eight ORs were included. In four ORs, breathing systems were replaced daily following standard practice. In the remaining four ORs, they were intended for a 7-day use. Breathing systems were sampled daily on three locations of the exterior surface and cultured for the presence of microorganisms. A total of 128 breathing systems were included, 99 from an OR with daily replacement and 29 from an OR with weekly replacement. A total of 604 samples were cultured, of which the majority, 549 (90.9%) cultures were negative. From the 55 (9.1%) positive cultures, the majority (n=49, 70%) were coagulase-negative staphylococci. None of the identified microorganisms were found in consecutive cultures. Cultures from day 2 to 7 did not show a statistically significant increased positivity rate compared to cultures from day 1, respectively 22.9% vs. 24.1%. The weekly replacement regimen, furthermore, decreased the number of breathing systems used with 71%. Our data indicates that use of breathing systems up to seven days remains microbial safe. Additionally, only a minimal number of pathogenic microorganisms were detected, and these were not persistent on the breathing systems. Transitioning from 24-hours to intended 7-day use could significantly reduce costs and CO2 emissions.

microbiology↗

bioRxiv2020

Impact of removing a concrete gas platform on benthic communities in the North Sea

Artificial structures such as offshore oil and gas platforms can significantly alter local species communities. It has been argued that this effect should be considered during decisions over their removal during decommissioning. In the North Sea, leaving such structures in place is prohibited but derogations are allowed for large concrete installations. To assess removal options for one such installation, the Halfweg GBS (gravity-based structure) a concrete platform foundation off the Dutch coast, we studied the resident fouling macrofauna community. The faunal structure, biomass and trophic composition of the Halfweg was then compared with those from the surrounding seabed sediments, other local artificial structures and a natural rocky reef. In total, 65 macrofaunal species were observed on the concrete (52 species), steel legs (32) and surrounding rock dump (44) of Halfweg. Mean Simpson diversity per sample was highest on the rock dump (0.71) but concrete (0.54) and steel (0.60) of the GBS were lower than seabed (0.69). Ten of the species observed on the concrete were not reported on other substrates while 10 of the species were also observed in the surrounding seabed. The GBS structure was numerically dominated by Arthropoda which comprised 98% of the total abundance. Mean ash free dry weight (AFDW) was significantly higher (p<0.001) on the Halfweg substrates (204 g AFDW per m2) than in the surrounding seabed (65 g AFDW per m2). Over 94% of the biomass on Halfweg consisted of the plumose anemone Metridium senile. While common on other reefs, this species was absent from the surrounding seabed. Macrofaunal feeding mechanisms of the concrete and rock dump communities on the GBS were similar to those of nearby sediments, although these differed from those on the Halfweg steel legs. Therefore, the presence of Halfweg alters the local community feeding modes. Multivariate analysis revealed that taxonomic structure of the GBS and other artificial structures significantly differed from that of the sedimentary habitats. Low numbers of non-indigenous species on Halfweg indicated that the structure does not act as a stepping stone for species invasions. Our data show that the Halfweg structures significantly increase local biodiversity and biomass. Removal of the concrete and steel legs of the GBS (leaving the rock dump) will significantly reduce local macrofauna biodiversity. The long-term impact on macrofaunal biomass is low. Leaving the complete Halfweg structure in place will result in an enriched local macrofaunal biodiversity and feeding mode diversity.

ecology↗