Evaluation of a disposable sheath bronchoscope system for use in the deployed field hospital.

At present, UK field hospitals use standard flexible bronchoscopes which require specialised disinfection services that are not integral to the hospital. This leads to prolonged turnover of used bronchoscopes as they have to be sent away to external facilities, which takes 1-3 days and is dependent on air transport to other facilities. In contingency operations, off site sterilisation facilities may not be available. There is a need for a bronchoscope system which can be rapidly cleaned and reused. We evaluated the Vision Sciences EndoSheath Bronchoscopy system, which uses a disposable outer sheath to remove the need for specialised disinfection. We report our experience of using this system in a deployed field hospital in Afghanistan.

Sepsis management in the deployed field hospital.

Sepsis, a syndrome caused by severe infection, affects a small proportion of military casualties but has a significant effect in increasing morbidity and mortality, including causing some preventable deaths. Casualties with abdominal trauma and those with significant tissue loss appear to be at a greater risk of sepsis. In this article, the diagnosis and management of sepsis in military casualties with reference to the Surviving Sepsis Campaign guidelines are examined. We discuss the management considerations specific to military casualties in the deployed setting and also discuss factors affecting evacuation by the UK Royal Air Force Critical Care Air Support Team.

Critical illness in the returning traveller.

A 70 year old man, who had recently travelled in rural Iraq, presented with fevers, rigors, and developed multiorgan failure. An extensive range of diagnostic tests was undertaken in an attempt to identify the cause. He was treated with multi-organ support and a number of antibiotics. Critical illness in the returning traveller presents a number of challenges on the ICU: obtaining adequate history, the potentially broad differential diagnosis, the requirement for numerous and sometimes specialised investigations and risks of infection transmission to staff and other patients. Travellers are more often elderly, more likely to have comorbidities and immunosuppression whilst global disease patterns are changing. Particular consideration should be given to unusual infections and venous thromboembolic disease from prolonged immobility whilst in transit, alongside more commonly encountered diseases. Antimicrobial resistance may be encountered and appropriate infection control is essential for the protection of patients, staff and others. Specialist support is available in the UK via the Imported Fever Service, especially for High Consequence Infectious Diseases. Consideration of non-infectious causes of fever and critical illness in returning travellers is also warranted. Crucially, a multidisciplinary team approach with thorough information gathering, repeated clinical review and judicious use of investigations are essential for optimal patient care.

Impact of ethnicity on the accuracy of measurements of oxygen saturations: A retrospective observational cohort study.

Background: Pulse oximeters are routinely used in community and hospital settings worldwide as a rapid, non-invasive, and readily available bedside tool to approximate blood oxygenation. Potential racial biases in peripheral oxygen saturation (SpO2) measurements may influence the accuracy of pulse oximetry readings and impact clinical decision making. We aimed to assess whether the accuracy of oxygen saturation measured by SpO2, relative to arterial blood gas (SaO2), varies by ethnicity. Methods: In this large retrospective observational cohort study covering four NHS Hospitals serving a large urban population in Birmingham, United Kingdom, consecutive pairs of SpO2 and SaO2 measurements taken on the same patient within an interval of less than 20 min were identified from electronic patient records. Where multiple pairs of measurements were recorded in a spell, only the first was included in the analysis. The differences between SpO2 and SaO2 measurements were compared across groups of self-identified ethnicity. These differences were subsequently adjusted for age, sex, bilirubin, systolic blood pressure, carboxyhaemaglobin saturations and the time interval between SpO2 and SaO2 measurements. Findings: Paired O2 saturation measurements from 16,818 inpatient spells between 1st January 2017 and 18th February 2021 were analysed. The cohort self-identified as being of White (81.2%), Asian (11.7%), Black (4.0%), or Other (3.2%) ethnicities. Across the cohort, SpO2 was statistically significantly higher than SaO2 (p < 0.0001), with medians of 98% (interquartile range [IQR]: 95-100%) vs. 97% (IQR: 96-99%), and a median difference of 0.5% points (pps; 95% confidence interval [CI]: 0.5-0.6). However, the size of this difference varied considerably with the magnitude of SaO2, with SpO2 overestimating by a median by 3.8pp (IQR: 0.4, 8.8) for SaO2 values <90% but underestimating by a median of 0.4pp (IQR: -2.0, 1.4) for an SaO2 of 95%. The differences between SpO2 and SaO2 were also found to vary by ethnicity, with this difference being 0.8pp (95% CI: 0.6-1.0, p < 0.0001) greater in those of Black vs. White ethnicity. These differences resulted in 8.7% vs. 6.1% of Black vs. White patients who were classified as normoxic on SpO2 actually being hypoxic on the gold standard SaO2 (odds ratio: 1.47, 95% CI: 1.09-1.98, p = 0.012). Interpretation: Pulse oximetry may overestimate O2 saturation, and this is possibly more pronounced in patients of Black ethnicity. Prospective studies are urgently warranted to assess the impact of ethnicity on the accuracy of pulse oximetry, to ensure care is optimised for all. Funding: PIONEER, the Health Data Research UK (HDR-UK) Health Data Research Hub in acute care.