ScienceBlog.ie

Propofol is very short acting hypnotic agent used to induce general anesthesia and to maintain patients who are mechanically ventilated. For those of you who have undergone general anesthesia, the milky white liquid is probably the last thing you see prior to being knocked out – as once injected propofol will induce unconsciousness in around 10 seconds. Due to its ability to impair memory while under its influence and its appearance as a white liquid, propofol is jokingly called “milk of amnesia” by medical professionals. Interestingly, Michael called propofol his “milk”.

It has several mechanisms of action, both through potentiation of GABA-A receptor activity, thereby slowing the channel closing time, and also acting as a sodium channel blocker. Recent research has also suggested the endocannabinoid system may contribute significantly to propofol’s anesthetic action and to its unique properties.

So What Went Wrong?

As with most cases of this kind, although propofol was the actual coup de grace, it was the combination of multiple drug interactions which ultimately led to Michael’s death. In a report released today, Michael was actually dosed with a 10-milligram tab of Valium (diazepam, a long-acting benzodiazepine) at 1.30am, followed by injections including two milligrams of lorazepam (a medium-acting benzodiazepine) around 2 a.m., two milligrams of midazolam (an ultra-short-acting benzodiazepine) around 3 a.m., and repeats of each at 5 a.m. and 7.30 a.m. respectively. That’s a lot of benzodiazepines!

Finally, at 10.40am, 25 milligrams of propofol was administered and Michael was dead within 10 minutes, most likely from respiratory depression caused by the interaction of high doses of benzodiazepines and propofol.

Alas, a totally avoidable death due to medical negligence on the part of a physician giving in to the demands of a patient.

- Eamonn

Written by Eamonn O'Raghallaigh

Eamonn holds qualifications in Science from UCD & RCSI and E-Business from NCI. In Life Science Recruitment, he specialises in the recruitment of professionals in the medical affairs and healthcare sectors and also works as an E-Business Consultant for Webscience Ltd.