lung overexpansion

[GJ DIVER]

Hi, I'm new to this forum and new to diving and am hoping to get some input on what I hope is not a silly question. On one of my first dives while working on fine tuning my bouyancy control I used what was taught in class namely to breath in to rise a little and then hover . The natural progression of events was to breath in some, not enough, breath in some more, still not enough until I had a full lung then of course I would start rising, only a little, but a few feet none the less. We never dove below 25' and were down ~30 min. so classic DCS was doubtful. After surfacing I had fatigue ,dizzyness,and the next day and for several days aches and chest pains.At the time it seemed these could also have been attributed to my arthritis, the cold weather and water, and the Dramamine I had taken. It wasn't until later I started thinking that what I explained earlier could have caused some mild or maybe not so mild "lung overexpansion". Even if not is this a procedure I should be worried about .

 

[WreckWriter]

I'm not a doc but sounds like CO2 buildup to me.

Tom

 

[BillP]

Howdy GJ Diver:

Welcome to the board! It's a good question, but there's no way to really give a good answer on an Internet message board. There are just too many variables to know what happened.

First, you bring up an important procedural concern. Yes, in diving you can inhale to ascend and exhale to descend. If you're properly neutrally buoyant to begin with you shouldn't have to have a "full lung" to ascend and it can be dangerous to try. Other divers and instructors can probably give you some technique tips if you're interested enough to post in the "Basic Scuba Discussion" forum.

You're right that "classic DCS" is unlikely after a 30min 25ft dive. You're also right that a primary concern with ascending with a "full lung" is a lung overexpansion injury- particularly if you're shallow where relative volume changes are greater. The effects of a lung overexpansion injury are usually noticed quite soon after the ascent. Dizziness can be a symptom of an arterial gas embolism from a lung overexpansion injury, and chest pain or tightness can be a symptom of lung barotrauma.

But usually those symptoms are associated with other signs of injury in cases of lung overexpansion, and other less serious causes can create the very same symptoms. For example, it's quite common for new divers to suffer mild middle ear barotrauma that can cause a feeling of dizziness after diving. Hauling gear, breathing cold air, breathing deeply when your not used to it can cause chest discomfort. When the cause is in question only a medical evaluation by medical personnel who know what to look for can tell the difference.

Sorry to not be more specific.

HTH,

Bill

The above information is intended for discussion purposes only and is not meant as specific medical advice for any individual.

 

[Laurence Stein DDS]

Welcome GJ Diver,

Just a comment on the bouyancy technique you discribed.

When done properly, this is indeed very useful. If properly weighted, and if PRIMARY neutral bouyancy is achieved, small additions or subtraction from the lung volume can allow for very precise control.

However, if this technique is used to achieve primary neutral bouyancy, then the technique is being misused. You shouldn't have to use a full lung full of air to begin to rise.

Another part of this technique is that while inhaling or exhaling to control bouyancy, you never seal the airway with the glottis, or simply, hold your breath, once you have made an adjustment to your bouyancy by this technique. You must inhale or exhale and allow the airway to remain open. If you pause the breath, the airway must still remain open by consciously using your breathing muscles to hold that chest position.

This is a fine distinction between holding your breath, in which the glottis is closed, and holding you inspiratory position of the chest, in which the glottis is open. While holding the position, air may still move between the lungs and the outside--this is the way to help prevent respiratory barotrauma.

BTW, this is not a silly question.

Have a happy new year.

Larry Stein

 

[GJ DIVER]

THANKS FOR YOUR RESPONSES. TOOTH DOCS REMARKS ON KEEPING THE GLOTIS OPEN TOOK A COUPLE OF MINUTES TO VIZUALISE BUT MAKES PERFECT SENSE ONCE I RELATED IT TO THE HUMMING PRACTICE TAUGHT IN CLASS. AT THE TIME I THOUGHT THAT WAS TAUGHT SIMPLY TO RELEASE AIR FROM THE LUNGS TO EQUALIZE LUNG PRESSURE. IT PROBABLY DOES BUT MORE IMPORTANTLY IT APPEARS TO BE IMMPOSSIBLE TO CLOSE THE GLOTTIS WHILE HUMMING. SEEMS THIS COULD BE A POINT IF A LITTLE MORE DETAILED IN THE PADI BOOK WOULD GO A LONG WAY TOWARDS UNDERSTANDING THE PROCESS OF TRAPPING AIR (OR NOT)IN THE LUNGS.