Chief Investigator: Dr Andrew Shepherd
The CApnography VAriation (CAVA) study was a nationwide survey of capnography traces used in airway management in NHS hospitals, in September 2024.
The aim was to ascertain the degree of variation in waveform capnography morphology in the UK, the compliance with the 2023 SALG best practice statement and the governance of waveform capnography between departments in the UK.
Primary objective
To identify the capnography waveforms utilized in anaesthesia practice across the UK.
Secondary objective
To determine what proportion of machines, comply with SALG standards.
Data were received from 138/420 (33%) eligible hospitals, and included 9052 individual capnography waveforms.
The SALG-recommended display is a white, solid, filled-in area graph positioned at the bottom of the monitor screen, but this was not the most common configuration.
The most common capnography display was a white line at the bottom of the screen, followed by the SALG-recommended standard and then a white line in the middle of the screen.
The survey identified variation in capnography waveform colour, waveform type, and screen position, with reported waveform colours including white, yellow, blue, grey, green, cyan, orange, violet and pink.
Waveforms varied between line traces and filled area graphs, creating differences in how the same monitoring parameter is displayed across clinical areas.
The findings showed ongoing national variation in capnography display despite SALG recommendations on standardisation.