Powered Respirators Are Effective, Sustainable, and Cost-Effective Personal Protective Equipment for SARS-CoV-2.

Objectives: The provision of high-quality personal protective equipment (PPE) has been a critical challenge during the COVID-19 pandemic. We evaluated an alternative strategy, mass deployment of a powered air-purifying respirator (PeRSo), in a large university hospital. Methods: We performed prospective user feedback via questionnaires sent to healthcare workers (HCWs) issued PeRSos, economic analysis, and evaluated the real-world impact. Results: Where paired responses were available, PeRSo was preferred over droplet precautions for comfort, patient response, overall experience, and subjective feeling of safety. For all responses, more participants reported the overall experience being rated "Very good" more frequently for PeRSo. The primary limitation identified was impairment of hearing. Economic simulation exercises revealed that the adoption of PeRSo within ICU is associated with net cost savings in the majority of scenarios and savings increased progressively with greater ITU occupancy. In evaluation during the second UK wave, over 3,600 respirators were deployed, all requested by staff, which were associated with a low staff absence relative to most comparator hospitals. Conclusions: Health services should consider a widespread implementation of powered reusable respirators as a safe and sustainable solution for the protection of HCWs as SARS-CoV-2 becomes an endemic viral illness.

An evaluation of the fixed concentration procedure for assessment of acute inhalation toxicity.

Acute inhalation studies are conducted in animals as part of chemical hazard identification and for classification and labelling. Current methods employ death as an endpoint (Organisation for Economic Co-operation and Development (OECD) test guideline (TG) 403 and TG436) while the recently approved fixed concentration procedure (FCP) (OECD TG433) uses fewer animals and replaces lethality as an endpoint with evident toxicity. Evident toxicity is the presence of clinical signs that predict that exposure to the next highest concentration will cause severe toxicity or death in most animals. Approval of TG433 was the result of an international initiative, led by the National Centre for the Replacement, Refinement & Reduction of Animals in Research (NC3Rs), which collected data from six laboratories on clinical signs recorded for inhalation studies on 172 substances. This paper summarises previously published data and describes the additional analyses of the dataset that were essential for approval of the TG.

Influence of provider type (nurse anesthetist or resident physician), staff assignments, and other covariates on daily evaluations of anesthesiologists' quality of supervision.

BACKGROUND: At many U.S. healthcare facilities, supervision of anesthesiology residents and/or Certified Registered Nurse Anesthetists (CRNAs) is a major daily responsibility of anesthesiologists. Our department implemented a daily process by which the supervision provided by each anesthesiologist working in operating rooms was evaluated by the anesthesiology resident(s) and CRNA(s) with whom they worked the previous day. METHODS: Requests for evaluation were sent daily via e-mail to each resident and CRNA after working in an operating room. Supervision scores were analyzed after 6 months, and aligned with the cases' American Society of Anesthesiologists Relative Value Guide units. RESULTS: (1) Mean monthly evaluation completion rates exceeded 85% (residents P = 0.0001, CRNAs P = 0.0005). (2) Pairwise by anesthesiologist, residents and CRNAs mean supervision scores were correlated (P < 0.0001), but residents assigned greater scores than did CRNAs (P < 0.0001). The pairwise differences between residents and CRNAs were heterogeneous among anesthesiologists (P < 0.0001). (3) Anesthesiologist supervision scores provided by residents were: (a) greater when a resident had more units of work that day with the rated anesthesiologist (P < 0.0001), and (b) less when the anesthesiologist had more units of work that same day with other providers (P < 0.0001). However, the relationships were unimportantly small, Kendall τb = +0.083 ± 0.014 (SE) and τb = -0.057 ± 0.014, respectively. The correlations were even less among the CRNAs, τb = -0.029 ± 0.013 and τb = -0.004 ± 0.012, respectively. (4) There also was unimportantly small association between a resident's or CRNA's mean score for an anesthesiologist and the number of days worked together (τb = -0.069 ± 0.023 and τb = +0.038 ± 0.020, respectively). CONCLUSIONS: Although the attributes that residents and CRNA perceive as constituting "supervision" significantly share commonalities, supervision scores should be analyzed separately for residents and CRNAs. Although mean supervision scores differ markedly among anesthesiologists, supervision scores are influenced negligibly by staff assignments (e.g., how busy the anesthesiologist is with other operating rooms).

Detection of mixed infection from bacterial whole genome sequence data allows assessment of its role in Clostridium difficile transmission.

Bacterial whole genome sequencing offers the prospect of rapid and high precision investigation of infectious disease outbreaks. Close genetic relationships between microorganisms isolated from different infected cases suggest transmission is a strong possibility, whereas transmission between cases with genetically distinct bacterial isolates can be excluded. However, undetected mixed infections-infection with ≥2 unrelated strains of the same species where only one is sequenced-potentially impairs exclusion of transmission with certainty, and may therefore limit the utility of this technique. We investigated the problem by developing a computationally efficient method for detecting mixed infection without the need for resource-intensive independent sequencing of multiple bacterial colonies. Given the relatively low density of single nucleotide polymorphisms within bacterial sequence data, direct reconstruction of mixed infection haplotypes from current short-read sequence data is not consistently possible. We therefore use a two-step maximum likelihood-based approach, assuming each sample contains up to two infecting strains. We jointly estimate the proportion of the infection arising from the dominant and minor strains, and the sequence divergence between these strains. In cases where mixed infection is confirmed, the dominant and minor haplotypes are then matched to a database of previously sequenced local isolates. We demonstrate the performance of our algorithm with in silico and in vitro mixed infection experiments, and apply it to transmission of an important healthcare-associated pathogen, Clostridium difficile. Using hospital ward movement data in a previously described stochastic transmission model, 15 pairs of cases enriched for likely transmission events associated with mixed infection were selected. Our method identified four previously undetected mixed infections, and a previously undetected transmission event, but no direct transmission between the pairs of cases under investigation. These results demonstrate that mixed infections can be detected without additional sequencing effort, and this will be important in assessing the extent of cryptic transmission in our hospitals.

A statistical evaluation of the effects of gender differences in assessment of acute inhalation toxicity.

Acute inhalation toxicity of chemicals has conventionally been assessed by the median lethal concentration (LC(50)) test (organisation for economic co-operation and development (OECD) TG 403). Two new methods, the recently adopted acute toxic class method (ATC; OECD TG 436) and a proposed fixed concentration procedure (FCP), have recently been considered, but statistical evaluations of these methods did not investigate the influence of differential sensitivity between male and female rats on the outcomes. This paper presents an analysis of data from the assessment of acute inhalation toxicity for 56 substances. Statistically significant differences between the LC(50) for males and females were found for 16 substances, with greater than 10-fold differences in the LC(50) for two substances. The paper also reports a statistical evaluation of the three test methods in the presence of unanticipated gender differences. With TG 403, a gender difference leads to a slightly greater chance of under-classification. This is also the case for the ATC method, but more pronounced than for TG 403, with misclassification of nearly all substances from Globally Harmonised System (GHS) class 3 into class 4. As the FCP uses females only, if females are more sensitive, the classification is unchanged. If males are more sensitive, the procedure may lead to under-classification. Additional research on modification of the FCP is thus proposed.

Acquisition of Streptococcus pneumoniae and nonspecific morbidity in infants and their families: a cohort study.

BACKGROUND: Most children are believed to acquire Streptococcus pneumoniae asymptomatically, with only a few developing overt S. pneumoniae disease. This study investigates the relationship between acquisition of S. pneumoniae and mild nonspecific infection leading to general practitioner (GP) consultation. METHODS: A prospective birth cohort study of 213 infants assessed at home 9 times during 24 weeks by nasopharyngeal swab and parental interview was conducted. RESULTS: All positive S. pneumoniae swabs (including acquisition and carriage) were significantly associated with GP consultations for infection by the study infant compared with infants with negative swabs [odds ratio (OR), 1.6; 95% confidence interval (CI) 1.1-2.2; P = 0.005]. There was a stronger association with S. pneumoniae acquisition alone (OR 2.1; 95% CI 1.3-3.4; P = 0.001) than with carriage only (OR 1.4; 95% CI 0.9-2.0; P = 0.1). Multivariate analysis confirmed that S. pneumoniae acquisition by the study subject was independently associated with GP consultations: adjusted hazard ratio, 1.8 (95% CI 1.1-2.9); P = 0.02. A similar and independent association was found between S. pneumoniae acquisition by the study subject, and GP consultations for infection by the family (adjusted hazard ratio, 1.8; 95% CI 1.1-2.8; P = 0.01). CONCLUSION: Acquisition of S. pneumoniae by the study infant was significantly associated with GP consultations for infection by the infant or family.