DAN® medical information specialists and researchers answer your dive medicine questions.
Q: During dive training in the pool, I couldn’t breathe after clearing my mask with my regulator in my mouth. After surfacing, I took six to eight wheezing breaths and then could breathe normally again. It’s possible I inhaled water during the exercise, but my instructor and I could not recall when or how that would have happened. Someone at the training center suggested that something might be wrong with my epiglottis. Is there a way to inspect the epiglottis to ensure it is functioning properly? What causes it to relax and open back up?
A: It is not uncommon for new divers to have some anxiety when fully removing their mask underwater. When you expose your nose to the water, it’s natural to feel uncomfortable if water enters the nasopharynx. Our bodies are trained not to take a breath while underwater, but it is possible if you can relax and focus on breathing through your regulator.
If water entered the larynx, the epiglottis’ natural response would be to close the airways to prevent aspiration. The larynx would reflexively trigger coughing to expel the fluid, or you would try to remove the fluid through exhalation. Even a small amount of fluid can induce laryngospasm, which will stimulate this powerful reflex.
This passage from Marieb and Hoehn’s Human Anatomy and Physiology is a good overview of how the epiglottis works: “When only air is flowing into the larynx, the inlet to the larynx is wide open and the free edge of the epiglottis projects upward. During swallowing, the larynx is pulled superiorly and the epiglottis tips to cover the laryngeal inlet. Because this action keeps food out of the lower respiratory passages, the epiglottis has been called the guardian of the airways. Anything other than air entering the larynx initiates the cough reflex to expel
the substance.”
Another possibility is that you had an anxiety-induced laryngospasm, which can be triggered by discomfort, panic, or high anxiety. Some physicians think this spasm is part of the body’s natural defense against accidental drowning or suffocation and may be part of the body’s response to fluid in the larynx.
Your breathing problem may be an issue with your comfort level and experience, but it’s possible there are other complications we cannot identify based on the information you provided. Discuss these concerns with your physician, and request a fitness-to-dive evaluation to ensure that you have no physical contraindications to dive activity. Your physician may refer you to an ENT for further investigation, if needed.
If your physician clears you for diving, we recommend that you complete additional, rigorous pool time to work on skills with your instructor before proceeding any further in your training.
— Ben Strelnick, NREMT, W-EMT
Q: Can someone diagnosed with pulmonary hypertension become a diver?
A: Pulmonary hypertension is considered a severe risk condition, and diving is not recommended for anyone with this diagnosis. Endurance disciplines such as diving, which are likely to pose the highest hemodynamic demands and require a high physical fitness level, are challenging for people with pulmonary hypertension. The stress that diving puts on the lungs and the right side of the heart may be too much for such an individual. Concerns of congestive heart failure or immersion-induced pulmonary edema are just two significant risk factors.
A person’s preexisting condition and exercise intolerance will affect the heart and lungs’ ability to perform underwater. Various factors while underwater lead to intravascular volume shifts to the central circulation involving the heart, coronary vessels, and lungs. In a healthy state, this increase in fluid usually causes no problem, but a person with pulmonary hypertension will struggle, sometimes even at rest, to keep up with the right ventricle’s increased workload as it tries to overcome the elevated pressure within the pulmonary vessels.
— Shannon Sunset, NCPT, NREMT
Q: I sustained a concussion a few weeks ago. When can I return to diving?
A: Given that your injury occurred a few weeks ago, it is still too early in your recovery to give specific return-to-dive recommendations. Diving may be possible for you, but whether it’s safe is not a quick and easy answer because there are many additional factors to consider regarding a concussion. If you experienced a loss of consciousness (LOC) that caused you to fall or that otherwise led to your concussion, however, you should seek further evaluation to determine the cause of that LOC and if that condition is compatible with diving.
The risk of seizures is one of the biggest concerns for determining fitness to dive after a head injury. The recommended waiting period before returning to diving varies depending on the degree of injury, recovery period, and seizure risk. Return to diving is based on your symptom-free recovery and evaluation by your physician team.
The best recommendation is to focus on your recovery and not resume diving during this period. Determining your seizure risk after your head injury is necessary before consideration for a return to diving. Once you are completely healed and released by your physician team for full, unrestricted activity, seek a fitness-to-dive evaluation with a physician who is knowledgeable in dive medicine before attempting to dive.
— Anne Strysniewicz, AEMT, DMT
Q: I have Marfan syndrome and would like information from someone who specializes in diving and its associated risks. My cardiologist has recommended against diving, but people with Marfan syndrome usually have limited physical activity, so I was not surprised. I have been treated my whole life and maintain a very active lifestyle, including swimming, water polo, basketball, and marathon running, against all recommendations. What are the risks for someone with Marfan diving, and is there anything I can do to mitigate them?
Marfan syndrome has an extensive spectrum of presentation from mild to severe and requires your physician team’s assessment. Many factors may have influenced your cardiologist’s recommendation against diving despite the active physical activities that you describe.
Physicians will carefully separate the list of appropriate activities. Diving affects various body systems, so the extra stress on systems that Marfan syndrome affects is an important consideration. The following are a few specific conditions to consider:
- Dilation and dissection of the aorta: Fluid changes that occur while diving may stress the aorta.
- Cardiac valvular conditions, cardiomyopathy, and dysrhythmias: These potential problems are often more significant if they occur underwater.
- Pneumothorax: Marfan syndrome can have a higher association with pneumothorax. There can be a risk of spontaneous pneumothorax (collapsed lung) with little or no inciting event. Although problematic on land, it is life-threatening while diving. Pulmonary barotrauma can cause a collapse of anyone’s lung. Upon ascent, trapped air expands and may cause a collapsed lung to develop into a tension pneumothorax, a medical emergency in which air cannot escape the pleural space around the affected lung, increasing
the risk of a pulmonary overinflation syndrome such as arterial gas embolism. - Scoliosis: Spine curvature has been associated with Marfan syndrome. Depending on the severity, scoliosis may cause a reduced exercise tolerance, making routine dive activities such as carrying gear, climbing a boat ladder, or swimming against a current more difficult.
- Spinal dura: There may be changes to the spine’s dura that can result in pain and headache. These changes may have a confounding impact on the diagnosis of spinal decompression illness (DCI).
- Thermal regulation: Wearing thermal protection can delay the core temperature drop from immersion in water, but you will eventually cool, and self-regulation may be difficult. You should review temperature regulation with your physician.
Medications and your baseline wellness are also worth reviewing. Some medications may have adverse reactions that may be a contraindication to diving. Your daily wellness is a necessary consideration, as are any regularly occurring pain or deficits that may make diagnosing DCI difficult. It’s essential to have an open discussion with your treating physician and follow their recommendations.
— Robert Soncini, NR-P, DMT