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Errors and inaccuracies in internet medical calculator applications: an example using oxygenation index
  1. Tallal Hussain1,
  2. Ian Braithwaite2,
  3. Stephen Hancock2
  1. 1 Paediatric Intensive Care Unit (L47), Leeds General Infirmary, Leeds, UK
  2. 2 Embrace Yorkshire and Humber Infant and Children’s Transport Service, Sheffield Children’s NHS Foundation Trust, Sheffield, UK
  1. Correspondence to Dr Tallal Hussain, Paediatric Intensive Care Unit (L47), Leeds General Infirmary, Leeds LS1 3EX, UK; Tallal.Hussain{at}

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The oxygenation index (OI) is a measure of the efficiency of oxygen exchange by the lungs. The pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FiO2) ratio is an alternative way of describing the severity of pulmonary dysfunction in ventilated patients. However, it does not take the mean airway pressure (MAP) into account, and therefore the OI is considered to be a more specific representation of oxygenation dysfunction.1

Box 1

Calculating the OI

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  • FiO2, fraction of inspired oxygen (%); MAP, mean airway pressure; OI, oxygenation index; PaO2, pressure of arterial oxygen.

The OI can be calculated using the formula in box 1. The PaO2 value should be obtained from an arterial blood gas sample. The units are important. The original references require the PaO2 to be in mmHg and the MAP in cmH2O.2 Although awkward in terms of the International System …

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  • Contributors TH and IB contributed to the acquisition of data from the internet websites and mobile phone applications, including the results and relevant findings. SH contributed to data analysis and interpretation. The review was drafted by TH and revised for important intellectual content by IB and SH. TH, IB and SH have contributed equally to the final approval of this case report.

  • Competing interests None declared.

  • Patient consent Not required.

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