Diving after pneumonia

[Duke Dive Medicine]

Hi, A lad I know had a fairly nasty bout of pneumonia. He seems to be fully recovered and is back to normal work duties and has no ill effects etc His doctor has allowed him to go back diving but he has to complete a number of dives up to 5metres (4 I think) followed by 2 dives up to a maximum depth of 20 metres. I am unsure if he is allowed to go further. Is this following any sort of protocol? It seems a little strange to me and would love to know the reasoning behind it or if it is just plucked out of the air? Thanks

Not knowing your friend's complete history, all anyone here can do is offer generalities, but for what it's worth:
As @kinoons said, after a serious bout of pneumonia there's a risk of a change to the lung structure that could result in air trapping, but that could lead to pulmonary barotrauma in depths even shallower than 5 meters. As @kinoons also mentioned, it would be reasonable to do a high-resolution CT scan to check for any remaining lung pathology, but if the scan is clear, then there's nothing to suggest that your friend would have problems diving. If the physician is concerned about air trapping, then he/she should not clear your friend to dive at all. A recommendation for test dives with a stepwise increase in depth to see whether he experiences pulmonary barotrauma is reckless at best.

This makes me wonder whether the physician is concerned about CO2 retention. Pneumonia can cause impaired gas exchange in the lungs, which can lead to retention of CO2 in the body. Other diving factors like increased gas density and the work of breathing of the regulator can also cause CO2 retention. Gas density increases with depth, so maybe that's the rationale for the recommendation for starting shallow. Again though, if the physician is concerned about CO2 retention, then the prudent thing to do would be to not clear the individual for diving until that concern has resolved, or perform testing on the surface if there's a facility in that region of the world that has that capability.

Best regards,
DDM

 

[Jonno]

Not knowing your friend's complete history, all anyone here can do is offer generalities, but for what it's worth:
As @kinoons said, after a serious bout of pneumonia there's a risk of a change to the lung structure that could result in air trapping, but that could lead to pulmonary barotrauma in depths even shallower than 5 meters. As @kinoons also mentioned, it would be reasonable to do a high-resolution CT scan to check for any remaining lung pathology, but if the scan is clear, then there's nothing to suggest that your friend would have problems diving. If the physician is concerned about air trapping, then he/she should not clear your friend to dive at all. A recommendation for test dives with a stepwise increase in depth to see whether he experiences pulmonary barotrauma is reckless at best.

This makes me wonder whether the physician is concerned about CO2 retention. Pneumonia can cause impaired gas exchange in the lungs, which can lead to retention of CO2 in the body. Other diving factors like increased gas density and the work of breathing of the regulator can also cause CO2 retention. Gas density increases with depth, so maybe that's the rationale for the recommendation for starting shallow. Again though, if the physician is concerned about CO2 retention, then the prudent thing to do would be to not clear the individual for diving until that concern has resolved, or perform testing on the surface if there's a facility in that region of the world that has that capability.

Best regards,
DDM

Thanks, I really appreciate your response. I was thinking along the lines of it was looking like non-non- destructive testing which I felt was indeed possibly dangerous. I am pretty sure we have the facilities. Thanks again.