The famous painting 'Girl with a Pearl Earring' (Meisje met de parel) by Johannes Vermeer has been in the Mauritshuis in The Hague since 1902. The painting has stimulated much interest and was the inspiration of a bestselling novel by Tracy Chevalier. Painted around 1665 it shows a girl under a blue and yellow headscarf with a mysterious and enchanting gaze. On her ear hangs a glittering jewel, a pearl. But despite the name of the painting is the girl really wearing a pearl? Recently Vincent Icke, professor of theoretical astronomy at Leiden University, has challenged this idea. His hypothesis, that the pearl is not a pearl at all, is based on the observation of reflections from the painting. Since pearls consist of thin layers of calcite they should scatter light of different wavelengths to create a soft white pearly lustre. In contrast the jewel in the painting has a bright reflection in the left corner and causes a reflection in the girl's collar. The dark part of the earring resembles the girl's skin and rather than pearl perhaps it is a silver or polished pewter earring.
What has this got to do with cardiology? Sometimes it is necessary to challenge the accepted view and take a closer look to reflect on where truth lies. Take the use of adrenaline in cardiac arrest. Ask anyone and they will tell you that during cardiac arrest you need to give adrenaline. If you have ever given adrenaline in this situation you will testify to its effects on blood pressure. For this reason adrenaline is regarded as essential for successful return of circulation after cardiac arrest. However recently people have started to challenge this idea and ask whether adrenaline is really that useful.
A recent study looked at the relationship between pre-hospital use of adrenaline and survival in people with out-of-hospital cardiac arrest. There were 1,556 patients of which 73% received adrenaline and 17% of these had a good outcome versus 63% of those who did not receive adrenaline. The adverse effects of adrenaline were observed regardless of length of resuscitation or in-hospital interventions performed. The adjusted odds ratio of intact survival was 0.48 for 1 mg of adrenaline, 0.30 for 2 to 5 mg and 0.23 for >5 mg. Therefore in a large group of patients who achieved return of circulation, pre-hospital use of adrenaline was consistently associated with a lower chance of survival.
Taken together with other observational studies there is now a randomised controlled trial called PARAMEDIC2 which will administer adrenaline or placebo to cardiac arrest patients and should help to address the question of whether it is help or harm in cardiac arrest. It is worth remembering that before the 1950's adrenaline and other pressor agents were used as standard treatment for all types of shock and it wasn't until later that there came an understanding that this was harmful and that fluid resuscitation was in fact required in most cases.
Dr Richard Bogle
The opinions expressed in this blog are strictly those of the author and should not be construed as the opinion or policy of my employers nor recommendations for your care or anyone else's. Always seek professional guidance instead.