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Utility of venous blood gases for the assessment of traumatic shock: a prospective observational study
  1. Andrew R Coggins1,2,
  2. Nurojan Vivekanandamoorthy3,
  3. Karen Byth4,
  4. Tabish Aleemullah3,
  5. Selwyn T Selvendran3,
  6. Rachel J Watkins3,
  7. Amith L Shetty2,
  8. Lorraine Devjak5,
  9. Jeremy M Hsu3,6
  1. 1Emergency Medicine, Westmead Hospital, Westmead, New South Wales, Australia
  2. 2Discipline of Emergency Medicine, The University of Sydney Westmead Clinical School, Sydney, New South Wales, Australia
  3. 3Department of Trauma, Westmead Hospital, Westmead, New South Wales, Australia
  4. 4Biostatistics Department, NHMRC Clinical Trials Centre, Camperdown, New South Wales, Australia
  5. 5Nursing Resources, Westmead Hospital, Westmead, New South Wales, Australia
  6. 6Discipline of Surgery, The University of Sydney Westmead Clinical School, Sydney, New South Wales, Australia
  1. Correspondence to Dr Andrew R Coggins, Emergency Medicine, Westmead Hospital, Westmead, NSW 2151, Australia; andrew.coggins{at}health.nsw.gov.au

Abstract

Background ABG samples are often obtained in trauma patients to assess shock severity. Venous blood gas (VBG) sampling, which is less invasive, has been widely used to assess other forms of shock. The study aim was to determine the agreement between VBG and ABG measurements in trauma.

Methods Patients were enrolled at an Australian trauma centre between October 2016 and October 2018. Bland-Altman limits of agreement (LOA) between paired blood gas samples taken <30 min apart were used to quantify the extent of agreement. The impact of using only VBG measurements was considered using an a priori plan. Cases where venous sampling failed to detect ‘concerning levels’ were flagged using evidence-based cut-offs: pH ≤7.2, base deficit (BD) ≤−6, bicarbonate <21 and lactate ≥4. Case summaries these patients were assessed by independent trauma clinicians as to whether an ABG would change expected management.

Results During the study period 176 major trauma patients had valid paired blood gas samples available for analysis. The median time difference between paired measurements was 11 min (IQR 6–17). There was a predominance of men (81.8%) and blunt trauma (92.0%). Median Injury Severity Score was 13 (range 1–75) and inpatient mortality was 6.3%. Mean difference (ABG−VBG) and LOA between paired arterial and venous measurements were 0.036 (LOA −0.048 to 0.120) for pH, −1.27 mmol/L (LOA −4.35 to 1.81) for BD, −0.64 mmol/L (LOA −1.86 to 0.57) for lactate and −1.97 mmol/L (LOA −5.49 to 1.55) for bicarbonate. Independent assessment of the VBG ‘false negative’ cases (n=20) suggested an ABG would change circulatory management in two cases.

Conclusions In trauma patients VBG and ABG parameters displayed suboptimal agreement. However, in cases flagged as VBG ‘false negative’ independent review indicated that the availability of an ABG was unlikely to change management.

  • trauma
  • assessment
  • majot trauma management

Data availability statement

Non-digital materials supporting this study are stored securely by the corresponding author. Data are available from the author (ARC) on request.

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Data availability statement

Non-digital materials supporting this study are stored securely by the corresponding author. Data are available from the author (ARC) on request.

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Footnotes

  • Handling editor Edward Carlton

  • Twitter @coggi33

  • Contributors JH, ALS, STS and RJW implemented, conceived and designed the study. ARC, RJW, TA and NV collated and the data. KB, LD and ARC analysed the data. All authors contributed to the data acquisition, manuscript preparation and subsequent revisions.

  • 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; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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