Björn Petruson, Göteborg, has devoted his professional life to nasal diseases. As a professor and senior physician at the ENT Clinic at Sahlgrenska University Hospital, his life has centred around treating patients, lecturing, researching and supervising post-graduate students.

Björn Petruson has written textbooks on the nose, developed pharmaceuticals and other treatment methods for various conditions in the nose and written a number of scientific and medical history books and articles.

As a medical consultant at Pharmacure AB, Björn Petruson guarantees the quality and scientific rigour of the company’s nasal products and product information. In this interview, he answers a number of topical questions about the nose, its function and illnesses.

Björn Petruson, how do human beings actually benefit from having a nose? Isn’t it just as easy to breathe through the mouth?

“To begin with, the nose is our organ of smell. Without the ability to smell, our lives would be far less enjoyable – and far more dangerous! “Breathing in through the nose has many positive effects. Jon Lundberg, Professor of Pharmacology at the Karolinska Institute in Stockholm, has demonstrated that the gas molecule, nitrogen oxide, which forms in the nasal sinus, has a positive effect on the blood vessels in the lungs.
“The blood vessels dilate and oxygenation improves. The longer competitors in the Vasa Ski Race, the Stockholm Marathon or other demanding sporting events can breathe through their mouths, the better.”

You mentioned the Vasa Ski Race. It can be quite cold at the start in Sälen. Is breathing through the nose also recommended at low temperatures?

“Absolutely. Breathing in through the nose humidifies and heats the air in a phenomenally effective way. It takes just five 100ths of a second for the air temperature to be raised from zero to 30 degrees while covering a distance of just seven centimetres. Breathing in cold air through the mouth, on the other hand, increases the risk of asthma, otherwise known as cold-induced asthma.”

What happens to the outdoor humidity at low temperatures?

“The lower the temperature, the drier the air. The drier the air, the greater the problems caused by dry mucous membranes in the nose. Problems caused by dry nasal mucous membranes are very common in the inland regions of Norrland in northern Sweden, for example. However, the relative humidity is low not only when it is cold outdoors but also in an indoor climate that is regulated by air conditioning. A flight to Thailand or the USA can also dry out the nasal mucous membranes. The air on board aircraft is very dry.
“Not everything can be blamed on the environment, however. Elderly people, and women in particular, develop dry mucous membranes as part of the ageing process.
“In addition to its ability to heat and humidify, the nose is also able to cleanse the air we inhale from particles in the air. All of us have worked in a dusty environment at some time and then blown our noses. Our handkerchiefs reveal just how much air pollution remains in the nose. Breathing in through the mouth does not have the same ‘filter effect’ as breathing through the nose.”

Snoring, overweight, blood oxygenation and the risk of heart attacks – could you explain how they are related?

“Snoring is a common phenomenon among people who are overweight. The reason is that the overweight, the ‘fat’, is located not just around the waist but also in the palate. When the size of the soft palate increases and reduces the air passages, inhalation is more difficult and the oxygenation of the blood in the lungs is therefore reduced. Snorers, especially the ones who stop breathing for short periods during sleep (otherwise known as sleep apnea), risk suffering heart attacks.
“It goes without saying that the best remedy is to change lifestyle and reduce body weight by not eating and drinking as much.”

Is nasal congestion as a result of a deviation in the septum a common complaint?

“Yes, this is a deviation that is well known to every ear, nose and throat doctor. It causes problems of different kinds for the patient, such as snoring, an increased tendency to develop nasal congestion in conjunction with allergies and so on. There are two main causes of septum deviation: damage during delivery and being exposed to violence later in life.
“As I wrote in the introduction to my surgical guide Med kniven i näsan (With a knife in the nose), interventions in the nose are not easy to perform. The area for surgery is very restricted and deep, making things difficult for one surgeon and naturally even more difficult for two. The intervention always takes place via the nostrils. The results are good, however; most patients are cured of their problems.”

Nosebleeds are one of your areas of research. How common are they?

“Studies reveal that four per cent of people in Sweden suffer from nosebleeds once or more every year. That is one person in every 25, which is quite a lot.
“You are correct in saying that I am interested in nosebleeds. My dissertation in 1974 focused on the problem from one particular angle – namely the coagulation capability of the blood. This interest eventually led to a new way of treating nosebleeds, Nozohaem®, which is in the process of being launched in Sweden and internationally.
“Nozohaem® originates from a clinical trial that was conducted several years ago in Göteborg in which it was shown that the placebo was more effective than the active substance.
“This clinical trial compared a gel containing a fibrinolysis inhibitor with a placebo, a 10-per cent solution of the simplest conceivable amino acid, glycine. The results revealed that glycine had a far greater haemostatic effect than the fibrinolysis inhibitor, which naturally never became a pharmaceutical.
“With my understanding of the way blood coagulants are formed and broken down, I quickly realised that glycine is one of the main constituents of collagen (connective tissue), which is needed to start the blood coagulation process.
¬“So this failure became a success, which is not an unusual phenomenon in medical research

Finally, a linguistic question. The “ceiling” of the nose, the bone that separates the nose from the brain, is called the ethmoid bone. Can you explain why?

“The word ethmoid comes from the Greek and means ‘sieve-like’. In ancient Egypt, people believed that the heart was the centre of the body and the seat of the soul. The brain’s sole task was to produce mucus to keep the nose moist.
“The belief that nasal mucus was produced by the brain and then dropped or was sieved through the opening at the top of the nose persisted for centuries.
“It was not until the 17th century that the Englishman Richard Lower, who was training to be a doctor, showed that this was not the case. He conducted an experiment which involved injecting ink into the cerebral fluid of animals and he revealed that that the ink was transported away, but not via the nose. None of the injected ink was found there.”