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Survey of blood gas interpretation
  1. Í O’Sullivan,
  2. R Jeavons
  1. Emergency Department, Bristol Royal Infirmary, Bristol, UK
  1. Correspondence to:
 Dr Íomhar O’ Sullivan
 Emergency Department, Bristol Royal Infirmary, Bristol BS2 8HW; Iomhar.O'

Statistics from

Hospital clinicians frequently request arterial blood gas (ABG) analysis to aid in the diagnosis and management of patients.

We carried out a one-day, survey to see how well ABG’s were interpreted. We asked 66 participants to complete a written questionnaire during their normal working duties. No one declined to take part. Respondents were asked to give the normal ranges for ABG parameters. Five different ABG results were presented and respondents asked to describe (free text) the findings and to give any number of differential diagnoses for each (free text). Responses were scored one point for each correct pH and for identifying correct metabolic/respiratory cause. A further point was awarded if acute, chronic, or compensated/mixed descriptions were correctly used. They received a further single mark for each appropriate differential diagnosis. Test examples had been chosen from real patient data. Correct results had previously been agreed by the surveyors and an independent ITU consultant.

54% of doctors correctly identified the normal range of values. 71% correctly described the abnormality shown in each example. 27% correctly produced two appropriate differential diagnoses. Surgeons and anaesthetists did better than most in the identification of normal ranges and the interpretation of results. ED staff obtained better results when listing potential diagnoses. Of ED staff, best overall results were returned by the three consultant respondents.

Results from this small snapshot survey imply the need for continued education of medical staff in the interpretation of ABG results. Given that only a quarter of our doctors offered correct differential diagnoses, we suggest that teaching should be directed towards the practical clinical use of gases as well as the theoretical background.

Table 1

 Specialty and grade of respondents

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