Venous and arterial base deficits: Do these agree in occult shock and in the elderly? A Bland-Altman analysis

Samuel Lunenfeld Research Centre (Y.Y.W.), University of Toronto, Toronto, Ontario, Canada
The journal of trauma and acute care surgery 03/2013; 74(3):936-9. DOI: 10.1097/TA.0b013e318282747a
Source: PubMed


Trauma centers are increasingly advocating the replacement of arterial blood gas measurements with venous blood gas measurements for simplification of base deficit (BD) determination. These values have never been demonstrated to agree in important trauma populations, such as for patients in occult shock (OS) or the elderly. The goal of this study was to investigate the level of agreement between venous and arterial BDs from blood gases in critically ill or injured patients, specifically in OS and the elderly.
This is a retrospective, consecutive, cohort study using matched pairs of venous and arterial blood gases from patients admitted to the Trauma and Neurosurgery Intensive Care Unit in a Level I trauma center in Toronto, Ontario, Canada. Agreement between near simultaneous arterial and venous BD was calculated using the Bland-Altman method. McNemar's test was used for differences in BDs in the presence or absence of OS and in elderly patients.
BDs for 466 arterial and venous samples from 72 patients were compared pairwise. There was no significant difference between samples (p = 0.88). Ninety-eight percent of samples were within 3.0 mmol/L of each other. No significant differences were detected between venous and arterial BD in the presence of OS or in the elderly (p = 0.72 and p = 0.25, respectively).
Arterial and venous BDs agree, including in the presence of OS and in the elderly. Consideration may be given to venous sampling both in the intensive care unit or in other areas of care, such as the trauma bay.
Diagnostic study, level III.

1 Follower
15 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Severity assessment in trauma patients is mandatory. It started during initial phone call that alerts emergency services when a trauma occurred. On-call physician assesses severity based on witness-provided information, to adapt emergency response (paramedics, emergency physicians). Initial severity assessment is subsequently improved based on first-responder provided informations. Whenever information comes, it helps providing adequate therapeutics and orientating the patient to the appropriate hospital. Severity assessment is based upon pre-trauma medical conditions, mechanism of injury, anatomical lesions and their consequences on physiology. Severity information can be summarized using scores, yet those are not used in France, except for post-hoc scientific purposes. Triage is usually performed using algorithms. Whatever the way triage is performed, triage tools are based on mortality as main judgement criterion. Other criteria should be considered, such as therapeutics requirements. The benefit of biomarkers of ultrasonography at prehospital setting remains to be assessed.
    No preview · Article · Jul 2013 · Annales francaises d'anesthesie et de reanimation
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background and objectives: To carry out a cross-sectional survey of the medical literature on laboratory research papers published later than 2012 and available in the common search engines (PubMed, Google Scholar) on the quality of statistical reporting of method comparison studies using Bland-Altman (B-A) analysis. Methods: Fifty clinical studies were identified which had undertaken method comparison of laboratory analytes using B-A. The reporting of B-A was evaluated using a predesigned checklist with following six items: (1) correct representation of x-axis on B-A plot, (2) representation and correct definition of limits of agreement (LOA), (3) reporting of confidence interval (CI) of LOA, (4) comparison of LOA with a priori defined clinical criteria, (5) evaluation of the pattern of the relationship between difference (y-axis) and average (x-axis) and (6) measures of repeatability. Results and interpretation: The x-axis and LOA were presented correctly in 94%, comparison with a priori clinical criteria in 74%, CI reporting in 6%, evaluation of pattern in 28% and repeatability assessment in 38% of studies. Conclusions: There is incomplete reporting of B-A in published clinical studies. Despite its simplicity, B-A appears not to be completely understood by researchers, reviewers and editors of journals. There appear to be differences in the reporting of B-A between laboratory medicine journals and other clinical journals. A uniform reporting of B-A method will enhance the generalizability of results.
    No preview · Article · Sep 2014 · Annals of Clinical Biochemistry