Thorax 63:289-290 doi:10.1136/thx.2007.091223
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Simple, easily memorised “rules of thumb” for the rapid assessment of physiological compensation for respiratory acid-base disorders

  1. J K Baillie
  1. Dr J K Baillie, Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, 54 Little France Drive, Edinburgh EH16 5SA, UK; j.k.baillie{at}

    Respiratory acidosis and alkalosis are associated with compensatory physiological changes, including extracellular and intracellular buffering, and altered renal ion handling. In clinical practice, mixed acid-base disturbances may be misdiagnosed if the expected magnitude of compensation for a primary respiratory disorder is not known.

    The ability to assess physiological compensation rapidly for acid-base disorders can be achieved either through intuition gained after many years of clinical experience, by use of a graph or nomogram,1 or through the application of one of the published formulae for predicting compensation.2 3 However, nomograms are often not readily available in clinical environments, and the most accurate formulae are complex and difficult to memorise reliably.

    A comprehensive summary of previously published measurements of metabolic compensation …