Find answers to the most frequently asked questions about diving medicine.
After an intense cold, during the first dive, I felt a severe pain in the middle of the brow, above my right eye and when I came to the surface, I saw that my mask was full of blood. Why did this happen and what should I do?
This problem is the 2nd most frequent of occurrence for divers, after the problem of equalization of the ears. It is also, practically, an equalization concerning the cavities filled with air that we have in the area of our forehead that are called frontal sinuses.
These are part of a complex system of air cavities that lie inside our head which are called paranasal cavities.
We don’t know the reason why God , in his infinite wisdom and love, has decided to construct us with a hollow forehead. We have confused him a little bit with our evolution and our decision to return to the sea so that he forgot to re-gift us with extra underwater skills.
There are various theories to explain why these air cavities exist within us.
reduction in head weight, which has allowed the human species to stand on both legs.
heat dissipation of the brain
function as a voice echo (which is why when we suffer for example from sinusitis, our voice is altered, among other things)
protection of soft molecules such as the brain, the eye or optic nerve, in case of an accident, with injury to the visceral skull, in a way which reminds us of the car’s airbag and the spatial network of its framework , which is deformed in a controlled manner to protect the valuable contents of the cabin, meaning us.
These cavities (sinuses, frontal sinuses, ethmoid cells, sphenoid sinuses ), communicate with the nose through very small openings. They are coated internally with a thin membrane, called mucosa and its main job is to produce mucus.
Normally, the daily production of mucus is about 1.5 liters, but it is not perceptible because it is in fine liquid form and moves with the help of thin hair, from the inner part of the sinuses to the lateral wall of the nose and from there to the throat where it is swallowed.
We realize that we do have mucus, when it increases in quantity or it becomes denser and sticky, so it does not move efficiently from our frontal respiratory epithelium and stagnates, causing us discomfort.
When we have a common cold or we suffer from an allergy, our nasal mucosa swells, increasing the amount and density of the mucus it produces.
Along with it, the mucosa that covers our nasal cavities also inflates. This gains clinical importance when it involves the mucosa of the sinus ostium( opening), an ostium that completely gets blocked and obstructs the free movement of air and mucus.
The concentration of mucus inside the sinus and its subsequent infection lead to the appearance of symptoms of acute sinusitis (headache, weight on the face, malaise, fever, etc.). The difficulty in the circulation of air through the swollen and clogged ostium is precisely the cause of the problem described.
In the diving phase we are obliged to send air in order to equalize the pressure in all of our air containing cavities, which happens when we equalize the air of the mask. If the frontal sinus ostium is closed, we feel a sharp pain in the eyebrow due to the difference in pressure manifesting itself from the very first meter of depth. What we should do is to stop diving immediately and make sure we contact our doctor in order to start medication.
If we insist on blowing, it is possible to violate the valve mechanism created by the swollen mucous membrane of the orifice, often by tearing it. This rupture may not occur only in the descent phase, but may happen also in the ascend reverse block phase (reverse block) . This explains the appearance of blood on the mask, which we will see as soon as we return to the surface.
The bleeding is not severe and usually stops on its own. This type of mucosal ruptures, however, especially when repeated, can lead to adhesions and permanent blockage of the sinus . The devastating consequence of this is our permanent expulsion from the wet field, unless we undergo surgery to re-open the obstructed ostium.
Even if modern surgery, using endoscopes, balloons and navigators, (image 4) has made things painless and much easier than the not-so-distant past, isn’t it much better to prevent something than trying to heal it?
So in order to avoid the permanent creation of thick mucosa, which can clog the sinuses, we thoroughly treat every episode of rhinitis or rhinosinusitis, for a sufficient period of time after attenuation of clinical symptoms.
We do not dive when we suffer from a common cold or an acute phase of allergic rhinitis.
We stop diving immediately, as soon as we find difficulty or inability to send air into one of our nasal cavities or if we feel intense, excruciating pain on the face.
The presence of blood in our mask should not leave us indifferent. We have to trace its origin.
And as the old ones used to say, a stitch in time saves nine.
Is it safe to use nasal decongestants to when diving?
First of all, I would like us to get to know, within a few lines, this group of medicine, widely used by underwater hunters. Anticholinergic or sympathomimetic substances are used as decongestants of the nasal mucosa, which cause the small arteries to constrict and reduce blood flow to the erectile tissue.
They are applied locally (inside the nose) in the form of nasal drops, sprays, ointment or gel or administered systematically orally. Ephedrine, phenylephrine, oxymetazolin, xylometazolin, nafazolin and ipratropio bromide belong to the first category. As for the second category, concerning oral medicines, various combinations of sympathomimetic amines with antihistamines are marketed.
The addition of antihistamines is justified by their atropinic action, which inhibits nasal secretions and their sedative action, which, although desirable during the night, can cause, on the other hand, sleepiness or slowdown of reflexes during the daytime.
This problem has been addressed to be solved, not with absolute success though, by the production of new generation of antihistamines, which certainly cause less repression than the corresponding older drugs.
These drugs are used to treat problems connected with the upper respiratory system (rhinorrhea, nasal congestion, sneezing), caused by conditions such as common cold, allergic or vasomotor rhinitis, etc.
The presence of edematous (swollen) mucosa in our nose, with increased, sometimes thin and sometimes thickened secretions (mucus), which can come out of our nostrils or flow back to our nose and throat or just standing and filling the cavities and corridors of our nose is a very serious problem for diving. This is because the dense mucus and swollen mucosa, narrow or completely block the openings of our paranasal cavities (sinuses, frontal sinuses, ethnoid cells, sphenoid sinuses) and lead us to possible barotraumas, while on the other side, the stenosis or obstruction of the eustachian tube, will lead to difficulty or inability to equalise thus to barotraumas of the ear.
So the use of these drugs, which deflate swollen mucous membranes and cause a decrease in nasal secretions, would seem like a miracle for our soul, a soul which perceives diving in the endless blue like an ideal lifeline. This beautiful theory though hides traps, which must be recognized, so that we can avoid them.
As with all medicines, each drug in this category has its own characteristics, one of which is its half-life, a parameter that determines how long it lasts on our nasal mucosa. . And this is a parameter which has general validity, but is also modified by the individuality and degree of activity of the person at a given time, as well as other parameters, some of which have not been studied at all, such as the effect of hyperbaric environment.
Simply put, the drug that has reduced or eliminated the swelling of our mucous membranes will at some point abandon us. This can occur abruptly or gradually and can lead to mucosal swelling like before the use of the drug or even greater due to the rebound effect (a familiar term in basketball).
If we let a basketball fall gently out of our hand, it will bounce to a height less than the original. But if we send it with force to meet the floor, it bounces to a higher height.
This is exactly what drugs of this class do in the nasal mucosa. Imagine what could happen if the edema returned to a greater degree than the original, finding us in an emerging phase, where the expanding-from the drop of barometric pressure-air, the one that fills the skull’s air cavities, will try to escape from the openings that will constrict or get blocked by edema or mucus.
The air, obeying the laws of physics, will forcefully attempt to find or even worse to create an escape route (drum, inner ear, even meninges and brains), with results ranging from very unpleasant to tragic.
And if the scuba diver has a hope of salvation, to stop the surfacing process and return to the previous depth, attempting again a very slow rise, perhaps giving the air time and way to escape from its natural path, the free diver has practically none. There are no tricks at such a difficult time to help the air find the right way to the surface.
Fear of causing a reverse block during the emergence phase, is therefore the first major objection to the use of decongestant drugs.
In addition, as stated on their packaging, this kind of medicine should only be used for a few days. However, the relief and temporary ease they provide to the diver make him prone to repeated and continuous use of them, violating this basic safety rule.
With constant use, addiction is caused. The effect of the drug diminishes gradually and increases the need for an ever-increasing dose. The final outcome is vasomotor rhinitis, a condition characterized by lesions of the mucous membrane with congestion and nose bleeding. ‘A third argument against the use of antihistamines we take orally is based on the fact that these can cause drowsiness, blurring of mental alertness, decreased critical ability and decreased reflexes, conditions that are not welcome in the hostile environment we will attempt.
In addition, as already mentioned, no experiments have been performed on any drug in order to study its action in the hyperbaric environment, meaning the seabed. Unfortunately we, the diving population, consist a very small group, indifferent to the global pharmaceutical community, for her to spend valuable (!) money on research on the impact of depth on pharmacokinetics.
This does not mean at all that we will exclude from the diving activity people with mild chronic conditions for which medication is taken.
In consultation with the doctor of the respective specialty or with the diving physician, the dosage adjustment and timing of taking the drug will be decided in relation to the dive.
The same applies to chronic or seasonal diseases, which require the use of nasal decongestants. We do not exclude, for example, from diving, people suffering from allergic rhinitis. However, we adjust the doses and time of taking their medicines in order to reduce or eliminate the risk. We take our antihistamine earlier in the afternoon rather than late at night (with caution when driving) and preferably use saline to do nasal washes, rather than sprays.
In case of nasal spray use, this should be done a few minutes before diving, keeping in mind that fishing should only last 2-3 hours, never more than that, even if we feel well, to avoid the risk of the rebound phenomenon and the reverse block that follows.
We will not dive when we are in the acute phase of allergic rhinitis, with severe nasal congestion and abundant nasal secretions, as well as when we have a cold.
We make daily use of nasal rinses with normal saline or sterile seawater, to remove mucus and all the inhaled pollutants and allergens that stick on them.
We do not hesitate to cancel an excursion when we are not feeling well.
Our favorite activity requires us to be perfectly healthy and in excellent physical condition, to always reward us in a unique magical way.
Can I dive, wearing earplugs in my ears, so that I don’t have to equalize the pressure on my ears?
The answer to this very important question is definitely NO. We are in a hurry to answer it bluntly and with clarity, although it is appropriate to analyze it in detail below, to avoid any misunderstandings, which could lead to tragic consequences.
If we place a watertight earplug in our external auditory canal (as shown in Figure 1) and attempt to dive from the surface (pressure 1 atm) to a depth of 10 meters (pressure 2 atm), then we will have created the following situation:
Between the earplug (b) and the tympanic membrane, we have isolated a closed cavity (c) containing air. This cavity has a solid and rigid bone wall, covered with skin. At one end it is tightly blocked by the ear plug while at the other end it has our elastic tympanic membrane.
At a depth of 10 meters, the external pressure of the earplug (a) is 2 atm, similar to the pressure of our inner ear (f), which due to the fact that it is filled with liquid, its pressure is always equal to the pressure of the rest of our body’s tissues, the pressure of depth. The pressure of space (c) is constantly 1 atm.
What happens here depends on what we choose to do for our middle ear space (e). If we try to equalize (as shown in Figure 2), that is send air to the middle ear, through the eustachian tube (g), by increasing the pressure to 2 atm, we will have created a pressure difference equal to 1 atm on either side of the drum, which exceeds its elasticity limits and will pierce it inside out.
If on the other hand we decide not to equalize and keep the surface pressure (1 atm) in our middle ear, then our drum will have the same pressure on both sides and will not be at risk of rupture. However, an undesirable 1 atm pressure difference will be created, on either side of the membrane of the round window, which is another hymen of the ear smaller in diameter, whose job is to seal the fluid space of our inner ear. This difference in pressure is capable of tearing this membrane and the inner ear fluids will get spilled into the middle ear.
This rupture of the membrane of the round window is a much more severe form of barotrauma than rupture of the eardrum, a real medical emergency that must be treated immediately, within the first hours or days of its occurrence, otherwise it will lead to partial or total hearing loss. It manifests with hearing loss, which we will feel as if having a plug in the ear, with a whistle in the ear that did not exist before, and may be accompanied by varying intensity of dizziness, with or without nausea and vomiting.
In conclusion, by wearing a watertight earplug and attempting to dive, we are called to choose between two situations, a bad one and an even worse one. So completely forget about using them and focus on your equalizations so that you can always return to the surface with no less than two ears.