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Journal update monthly top five
  1. Robert Hirst1,
  2. Hannah Courtney2,
  3. Tom Dickinson3,
  4. Stephanie Milne4,
  5. Kieran McDonnell5,
  6. Sally Wright1,
  7. Francesca Hinds3,
  8. Jonathan Benger6,7
  1. 1 Emergency Department, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
  2. 2 Emergency Department, Great Western Hospital Foundation NHS Trust, Swindon, UK
  3. 3 Emergency Department, Musgrove Park Hospital, Taunton, UK
  4. 4 Gloucestershire Royal Hospital, Gloucester, UK
  5. 5 Great Western Hospital Foundation NHS Trust, Swindon, UK
  6. 6 Faculty of Health and Life Sciences, University of the West of England, Bristol, UK
  7. 7 University of the West of England, Bristol, UK
  1. Correspondence to Dr Robert Hirst, Emergency Department, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol BS2 8HW, UK; robert.hirst{at}

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This month’s update is by the Research in Emergency care, Avon Collaborative Hub based in Bristol. We used a multimodal search strategy, drawing on free open-access medical education resources and literature searches. We identified the five most interesting and relevant papers (decided by consensus) and highlight the main findings, key limitations and clinical bottom line for each paper.

The papers are ranked as:

  • Worth a peek—interesting, but not yet ready for prime time.

  • Head turner—new concepts.

  • Game changer—this paper could/should change practice.

Low perfusion and missed diagnosis of hypoxemia by pulse oximetry in darkly pigmented skin: A prospective study by Gudelunas et al.

Topic: diagnostics

Rating: game changer

Retrospective studies have suggested pulse oximetry readings may overestimate oxygen saturation (SpO2) in patients with darkly pigmented skin, resulting in higher rates of occult hypoxaemia.1

This prospective study evaluated the accuracy of two different pulse oximeters in 146 recruited subjects who were categorised into different skin pigment groups: 43 dark, 78 medium and 25 light skin tones. Researchers collected data from 9763 paired pulse oximetry readings (SpO2) and arterial oxygen saturation (SaO2) during induced controlled hypoxaemia (SaO2 68–100%) in healthy volunteers. Perfusion index (PI) was measured with low perfusion defined as PI <1%. The primary analysis aimed to understand how pulse oximeter accuracy varied across different skin pigment categories, considering PI, degree of hypoxaemia, age and sex.

The study found skin pigment, PI and degree of hypoxaemia all contributed to pulse oximeter bias (the difference between SpO2 and SaO2). In medium and darkly pigmented subjects, bias increased with degree of hypoxaemia and low perfusion. The combined frequency of missed hypoxaemia was 1.1% for light, 8.2% in medium and 21.1% in dark skin. Limitations included evaluating only two pulse oximeters. Additionally, the study focused on healthy individuals in controlled laboratory conditions and the findings might not translate to critically ill patients or dynamic oxygenation states.

Bottom line

Hypoxaemia …

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  • Contributors All authors played a part in the literature search, creation, writing and editing of this manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; internally peer reviewed.