We all know what snoring is, but do we understand what snoring means? I know that there will be snoring experts out there. I hope to find someone who can explain the pathophysiology of snoring in acute respiratory failure. Let us focus on the basics: what causes the sound of snoring? It is the sound caused by air flowing past relaxed tissues in the upper respiratory tract producing vibrations. It is primarily the uvula and the soft palate that can relax enough to partially block the airway in the supine position. This results in an irregular airflow and the vibrations. I can understand that, but what about snoring if the patient is prone? A fascinating aside here is that astronauts have reported snoring in space!

What is the relevance to this case?

If a person is snoring that means they are breathing. If they are breathing and their skin is of a normal colour does that suggest that they are oxygenating the tissues? This was the situation described by the support staff who were tidying up the operating room and observing the patient. All sedation had been stopped and there were no active drugs in the system when toxicology was reported at the post-mortem.

So how does this fit in with the prosecution case?

The prosecution case is that the patient was so heavily sedated that she developed respiratory failure leading to hypoxic hypoxia and cardiac arrest and death. So, although she was no longer sedated, she had suffered terminal damage to her brain from hypoxia and died as a result.

I feel very uncomfortable when I hear this type of explanation, which is selective in facts and ignores some key elements of the clinical picture. The reason I find this so disturbing is that I was taught extremely well at medical school and one of the key messages is not to be selective when assessing symptoms and signs to determine a diagnosis. The temptation of the junior medical student is always to make a number of diagnoses each based on a selective combination of clinical features. No! The professor would say. The good doctor tries to make a single diagnosis which explains all the clinical features. In the course of background reading for this short blog I came across a book, Improving Diagnosis in Health Care. Chapter two, The Diagnostic Process is available online: (https://www.ncbi.nlm.nih.gov/books/NBK338593/). It is interesting to read this in the context of having graduated over forty years ago. Yes, medicine has become ever more complex and the diagnostic toolbox ever more sophisticated, but the fundamental lesson appears unchanged; try to achieve a single diagnosis to explain the range of clinical features.

Back to snoring. It is a sign of life, not death, and is very different from the ‘death rattles’ associated with the final hours of a patient dying with broncho-pneumonia (infection in the lung tissues). So, I am putting this out there.

Snoring. Normal skin colour. Is this to be expected in a patient who has been overdosed with sedative drugs and has developed a terminal respiratory failure?

This is not my field of expertise.

Andrew Burd (Prof)

The Chinese University of Hong Kong.

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