Dear Eric. Thank you so much for your kind and wise comments and for your encouragement. We value our fellow diving physician's input and thoughtful comments. Again, thank you so much. Kind regards, Frans

Hi Gabi, thanks for engaging. You raise several valid points. A major element of this discussion revolves around the risk of seizures associated with bupropion and the risk of an instructor with bipolar disorder possibly putting his students at risk. First, a quick note on Bupropion: Bupropion has been linked to an increased risk of seizures (from 1/1000 on lower doses to 4/1000 on 450 mg). Certain people are more susceptible, such as those with a history of seizures, eating disorders, or those withdrawing from alcohol or sedatives. Numerous case reports and ongoing surveillance have documented seizures in patients taking bupropion, often associated with dose increases or existing risk factors. While the exact cause is unclear, it’s believed that bupropion's impact on brain chemicals may trigger seizures. Despite its benefits, it's important to be aware of this risk and use the medication cautiously. Given that seizures have a high risk of drowning underwater, this is not an insignificant risk. The additional confounding factor is being an instructor. In DAN Southern Africa, we consider Bupropion use a contra-indication to diving. It has also been ruled as unsuitable for Commercial Divers and Pilots. Thank you for your suggestions for mitigating the risk of using a divemaster. Kind regards, Frans

Hi Imam. Thank you for asking. If I understand your question correctly, my response would be that our lungs are compressible, and a dive cylinder is not. However, when we breathe compressed gas underwater, the gas pressure in our lungs must be at ambient pressure for us to breathe easily on demand. The gas in the cylinder is not compressed, but the amount of gas extracted from a dive cylinder would be greater the deeper we dive. I hope that addresses your question. I hope this translation in Bengali will be accurate - only you would know: হাই ইমাম। জিজ্ঞাসা করার জন্য ধন্যবাদ। যদি আমি আপনার প্রশ্নটি সঠিকভাবে বুঝে থাকি, তবে আমার উত্তর হবে যে আমাদের ফুসফুস সংকোচনযোগ্য এবং ডাইভ সিলিন্ডার তা নয়। তবে, যখন আমরা পানির নিচে সংকুচিত গ্যাস শ্বাস নিই, তখন আমাদের ফুসফুসে থাকা গ্যাসের চাপ আমাদের সহজে শ্বাস নিতে পারার জন্য পরিবেষ্টিত চাপের সাথে সামঞ্জস্যপূর্ণ হতে হবে। সিলিন্ডারের গ্যাস সংকুচিত নয়, কিন্তু আমরা যত গভীরে ডুব দেব, ডাইভ সিলিন্ডার থেকে তত বেশি গ্যাস বের করা হবে। আশা করি এটা আপনার প্রশ্নের উত্তর দেয়।.

Dear Darren, thank you for your comment. Indeed -- in addition to the risk of low blood glucose, scuba divers with diabetes should be concerned about secondary complications like heart disease, kidney disease, and neuropathy. Diabetic retinopathy is not worsened by the elevated pressures while diving, but visual acuity remains a safety concern. The pressure in the eye generally increases in proportion to other body fluids. However, if the face mask is not equalized, suction on the eye can cause issues like rupture of a weak cornea. Retinal detachment could be a concern, but other impacts on the retina are not considered significant. Thank you for your comments. Kind regards, Frans

Thanks for the great question: The evolving nature of CPR guidelines is primarily due to continuous research and advancements in medical science. The American Heart Association (AHA) and other global health organizations regularly review and update their guidelines based on the latest evidence and studies on cardiac arrest and resuscitation. Here are some reasons why CPR details have changed over the years: (1) Improved Understanding: Our knowledge of human physiology and the mechanics of cardiac arrest improves over time. New research can provide insights into more effective ways to perform CPR. (2) Technological Advances: Better monitoring and diagnostic tools help researchers understand the impact of different CPR techniques, leading to more refined and effective guidelines. (3) Statistical Data: Ongoing analysis of survival rates and outcomes from real-life CPR cases helps in identifying best practices and areas needing improvement. (4) Global Collaboration: Collaboration between various health organizations worldwide leads to a consensus on the most effective practices, which are then adopted and recommended universally. Regarding your observations about the DAN (Divers Alert Network) video and its lack of specific compression numbers, here are a few points: (1) General Principles Over Specifics: Some training materials focus on the general principles of CPR rather than specific numbers to emphasize the importance of high-quality, uninterrupted chest compressions over precise counting. (2) Context-Specific Guidance: CPR guidelines might differ slightly depending on the context, such as land-based emergencies versus water rescues. For instance, in water rescues, the priority is often to remove the person from the water safely before starting CPR, which might affect how and when compressions and breaths are given. (3) Current Guidelines: As of 2024, organizations like the AHA recommend 100-120 compressions per minute for adult CPR, with rescue breaths still considered important, especially for situations like drowning where the primary issue is often hypoxia (lack of oxygen). (4) DAN and Rescue Breaths: In water rescue scenarios, rescue breaths are crucial since drowning victims typically suffer from a lack of oxygen. DAN and other water rescue training emphasize the importance of providing rescue breaths as soon as it is safe and feasible to do so. This might involve giving breaths while still in the water if it can be done safely. Since you are about to take a CPR course provided by your workplace, you will likely receive the most current and context-specific guidance. It's a good opportunity to ask the instructors about any differences between land-based and water-rescue CPR techniques and how they align with the latest research and guidelines. Thank you again for some great questions!

Thank you for pointing out these crucial considerations, Kambiz. It's indeed vital to recognize that diving while experiencing uncontrolled manic or depressive states is highly unsafe, particularly during manic episodes, due to the potential for risky behaviors. Additionally, the effects of certain medications can increase the risk of drowning and make diving in hazardous conditions even more dangerous. Ensuring that any diver is both mentally stable and not adversely affected by medication is essential. I also agree that it would be highly exceptional for an Instructor to be approved to provide instruction with a confirmed diagnosis of Bipolar Disorder treated with medication -- for the safety of both the instructor and their students. Your insights highlight important safety protocols that must be adhered to in diving instruction. Thank you so much, Dr Frans Cronje

Thank you Kambiz. Yes, my personal advice would be conservative, as you suggested. If the individual is stabilized on medication with a better safety profile than bupropion, I will reconsider. This is the type of situation I would not make an individual decision on fitness. I would solicit the opinions of diving medical colleagues to have a consensus verdict. Thank you again.

Thank you for sharing your thoughtful perspective, Tanja. It's understandable to have concerns about the safety of both the instructor and the students in such situations. Your points about the importance of ensuring an instructor is not prone to risky or reckless behavior during a period of instability are well-taken. Educating potential students about the instructor's condition is a considerate approach, allowing them to make informed decisions. Additionally, respecting the personal autonomy of the instructor to dive, as long as it doesn't endanger others, is a balanced view. Whether it is possible to allow Instructors to dive with any potentially unstable mental health problem poses various challenges, including liability for the dive operator or resort. It's clear that your reflections come from a place of care and a desire to prioritize safety, which is essential in this context. Please read my response to Kambiz's comment below for additional information. Kind regards, Dr Frans Cronje

Hi Tanja, I like your succinct summary. A good track record of medication stability and safety, disclosure of the condition, and avoiding endangering others would be three important governing principles. The challenge would be the practical implementation. Thank you for your valuable perspectives!

Interesting question. Inner Ear Barotrauma almost never occurs without concurrent straining maneuvers to equalize (i.e., forced prolonged Valsava maneuvers). Even elevator descents from the tallest skyscrapers in the world are unlikely to require such strainful efforts. One scenario in which inner ear barotrauma may occur is if there is a sudden rise in intracranial pressure after there has been a mild prior episode of inner ear barotrauma. For instance: We had this happen to a fireman. He had struggled to equalize the ear during a dive, and the next day, after carrying and nearly tripping with a patient on a stretcher, he developed sudden vertigo and deafness. This delayed form of inner ear barotrauma is rare, but it can occur. I am not sure if I have addressed your answer satisfactorily, so please refine your question if you need more information. All the best, Dr Frans Cronje

​@DrFJCronje hello Dr Frans, 4 years ago I had bacterial sinusitis from an Oro-Antral fistula after tooth #2 was extracted. The infection spread to both ears (I lost 95 percent of my hearing in one ear for a few hours and then I had pain in both eats with popping and crackling). I got tinnitus from this and in a desperate attempt to resolve my tinnitus I did the Valsalva maneuver a few times. While doing the valsalva maneuver I would: pinch my nose and close my mouth and slow to moderately blow out my nose to open my eustachian tubes. I would hear one open then I would continue to to do the valsalva maneuver until I heard the 2nd ear pop... then I would keep blowing a little longer then I would hear a weird noise from either my tympanic membrane expanding like a sail on a sailboat, my ossicular chain moving or both. I have normal audiograms but I have permanent bilateral high pitched tinnitus and my voice permanently and subjectively sounds like a broken speaker. What kind of damage could I have done to my inner ear? I never had vertigo. I eventually saw a few Nuerotologists to rule out Lateral/horizontal Semicircular Canal Dehiscence Syndrome (at John's Hopkins here in the states). Again , could I have caused permanent damage from doing the valsalva when I never ruptured my Tympanic membrane or my round or oval windows? I was 43 when this happened. Perfect hearing before the infection. My voice subjectively has sounded distorted eversince all those events occured 4 years ago. My voice sounds 85 percent normal with intermittent cacophony that shadows my voice and that occasionally gives me the nails-on-a-chalkboard like sensation. My recorded voice sounds normal to me (my normal recorded voice). My voice sounds the same to everyone but myself. I don't know if the damage in my maxillary sinus cavity could still be causing this OR if there is permanent damage to my inner ear? I have normal vemp tests, normal ABR, normal audiograms, normal CT scans and a normal MRI. I have been depressed and in severe distress over this everyday since this happened. What is your opinion what happened? Thanks

Same happens with me

Thanks for the comments. I agree that if you struggle with external otitis the Pro Ear mask or Docs Pro Plugs are very helpful! Dr Frans Cronje

It’s not always simple - it’s been a problem for me for 200+ dives, and Doc’s Proplugs are the solution for me - my one ear canal just traps water.

@@gavinsmith28 sorry to hear that, my father told me how to take care of it when i first started to swim.

@@garyengelman7867 different people have different issues….

Hi Matthew. I am fascinated by the remedy you suggest. Could you provide some more details? Do you mean you fill the external ear canal with warm water? If so, it may be that the heating of the middle ear space through the paper-thin eardrum alleviates a bit of the reverse block, but I must say, I have not heard about this remedy before. Well, we keep learning every day. Dr Frans Cronje

Hi Christian, thanks for the question. It really depends on why the air got there. If it is due to a rib injury, it may just need to heal. If it happened without explanation, then there may be a problem. Feel free to clarify. Dr Frans Cronje

Dear Darth. Thank you for your important question. The short answer is that anything that causes the alveolar of the long to rupture into communal clusters causes blebs and predisposes a person to a spontaneous pneumothorax, as these blebs are more prone to abnormal expansion according to La Place's Law. This may be due to connective tissue abnormalities (like Marphan or Ehlers-Danlos Syndromes) or toxic and fibrotic processes (like silicosis and smoking). Here is a comprehensive article that discusses the topic more exhaustively. Blunt force trauma to the chest may also cause blebs, so we are always wary of letting someone after a motor vehicle accident go back to diving without a chest X-ray. Many people have blebs that do not seem to cause difficulties. During the COVID-19 pandemic, many people had high-resolution CT scans. Pulmonary blebs were seen so commonly that they were not even reported later. Our pragmatic approach is that lungs without obvious abnormalities on a Chest X-ray may be assumed to be 'normal.' However, once there has been a suspicious event or if there are underlying / predisposing factors, a high-resolution CT scan is the best test to look at the structure. Lung function in the form of body plethysmography can identify possibly suspicious abnormalities, but CT remains the gold standard. Blebs, alone, are not always a contraindication to diving. Blebs in the upper parts of the lung are sometimes considered to not be dangerous. However, blebs in the parts of the lung that have high circulation are at risk of suffering gas embolism or rupture. So, these may be disqualifying. Here is the comprehensive article: www.ncbi.nlm.nih.gov/pmc/articles/PMC5569604/. Kind regards, Dr Frans Cronje

Dear Filip. Thank you for your question. The answer is not quite so simple in your case as it seems to have developed fairly late. My recommendation would be to see a Pulmonologist and have full body plethysmography and a high resolution CT of the chest. This might indicate how likely it is for you to develop another spontaneous pneumothorax, what the risk of arterial gas embolism is, whether free diving might put you at risk by precipitating another event. I would also recommend you refrain from any diving until these questions have been answered. Hope that helps! Take care. Dr Frans Cronje

Glad you enjoyed it!

Thank you for your support and faith in the DAN service.

Glad you enjoyed it

Thank you for your question! Dental implants usually do not entrap bubbles. The highest risk for dental pain or tooth implosion or explosion is poor fillings. Crowns and veneers are usually not a problem. The critical issue is entrapped gas or, more specifically, a type of one-way collection of gas under a lousy filling. It is undoubtedly advisable to wait a few days after dental surgery (until completely pain-free) or a filling (at least 48 hours after or 24 hours after the analgesic/local anaesthetic has worn off) and resuming diving. Fresh fillings (especially amalgam ones (which are becoming less common) can conduct cold temperatures from the water or inhaled cold gas/air) and cause discomfort, but a well-performed filling is typically not a problem. If there are doubts, a routine dental X-ray (panorex) can identify trapped bubbles under poor or decayed fillings. Thanks for your comments that allowed us to post this expansion on the topic. Dr Frans Cronje

Thank you for your response.

Dear Christa. Thank you for your comments. Importantly, there is, of course, a distinction between a dental filling (especially a poor or decayed one) and a dental implant. Dental implants involve screwing a titanium-threaded prosthesis into the mandible or maxilla and, after a rest (osseointegration period), attaching the tooth cap or dental appliance. Dental implants usually do not entrap bubbles. The highest risk for dental pain or tooth implosion or explosion is poor fillings. It is undoubtedly advisable to wait a few days after dental surgery (until completely pain-free) or a filling (at least 48 hours after or 24 hours after the analgesic/local anaesthetic has worn off) and resuming diving. Fresh fillings (especially amalgam ones (which are becoming less common) can conduct cold temperatures from the water or inhaled cold gas/air) and cause discomfort, but a well-performed filling is typically not a problem. If there are doubts, a routine dental X-ray (panorex) can identify trapped bubbles under poor or decayed fillings. Thanks for your comments that allowed us to post this expansion on the topic. Dr Frans Cronje

Thank you for your response.

Sorry about that. Here is the link dan.org/alert-diver/article/gradient-factors/