Hyperbarric O2 Therapy (HBO) is proven to be helpful in the surgical care of patients post radiation therapy for head and neck cancer. I have one patient with known COPD who became hypercarbic and somnolent after every HBO treatment requiring BiPAP support for about 2 hours after each session. Simple O2 supplementation was not having this effect. Just HBO.
Hi Paul, Signs of pulmonary oxygen toxicity are irritating cough, a sternal burning sensation etc. Neurological oxtox is very rare and manifests itself as a in chamber convulsion. This sounds more like a patient who depends on his hypoxic drive for ventilation. One HBOT session will give a huge pO2 that will cause hypoventilation long enough to develop hypercapnia that may have resulted in a coma. I would say that HBOT is contraindicated in this case. Interesting problem.
Most likely this patient becomes hypercapnic actually during hyperbaric therapy. There are three reasons why this can occur: (1) increased breathing resistance due to the higher gas density; (2) increased physiological deadspace; (3) inhibition of chemosensitivity by hyperoxia. The fact that it lasts for awhile after treatment is probably a reflection of his high baseline airways resistance.
Hi Paul, I agree with both the above. Once the patient becomes somnolent and hypocapnic with CO2, the condition may be quite persistent (or terminal). We take care to try and filter these customers out. They are rarely good candidates on the balance of risk and benefit.
Dear Paul
What exactly is the need for the HBO therapy? Is the problem one (necrosis?) where some local method may be useful, such as hydrogen peroxide solution (for gargle/local application)? Or some local perfusion method can be devised? Use Erythropoietin and/or packed cell transfusion? Use Allosteric effectors of Hb such as effaproxiral which shifts O2 dissociation curve to right; or PFC or Hb based oxygen carriers?
That you needed the HBO is an indication that the patient is in a poor state, and deserves all possible interventions; I know, Head and neck cancers have been my speciality; and both recurrence and radiation effects as well as effect of surgery in irradiated patients are very heartbreaking events
Narayanan Bhattathiri
My thanks to all of you for your answers. I agree with the idea that this person's hypoxic drive was overwhelmed by the HBO. You've confirmed that no one had cited this as an issue. Be sure I've recommended against it after his second course when he did the same thing. Givens airway stenosis and airway surgery, it was assumed that this was a manifestation of the post surgical effect. Clearly that is not the case. He had his third stage surgery and did fine without the HBO. Of course this is clinical medicine and not SCIENCE! The reason for his getting the HBO in the first place was due to surgery in irradiated tissues. The healing was expected to be very deficient. It was but regardless he has done very well, is eating a largely unrestricted diet PO and breathing well with a good voice. This is the triple-crown of upper aerodigestive laryngeal surgery!
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