Im sorry to hear about your mother.
Now Ativan or for that matter any benzodiazepine can be dangerous in a patient with COPD, simply because it can cause respiratory depression , secondly if a patients age is greater than 60 years there is a tendency for it to be accumulated inside the body and then excreted much more slowly than in patients who are younger. In addition if your mother had a slight kidney issue that would also increase the time it would take for the drug to be excreted out of the body. Now Considering her situation after the ativan was used, it is possible that any of the above three scenarios occurred in her case. Now Ativan is a relatively short acting drug however if benzodiazepines are to be used in patients who may have a tendency to lapse into an altered state of consciousness, then midazolam is preferred because it is the shortest acting drug and will leave the body much sooner than any of the other BDZs.
Now apart from the coma it is possible that your mother also developed some respiratory depression due to the rapid administration of ativan or rather frequent administration of ativan, if that happened then she would have started to retain carbondioxide in her body, which patients of COPD tend to do if they are having an acute attack. This accumulation of CO2 would have led to further worsening of the conscious level. That is why patients with acute exacerabation of COPD in the ICU are always given benzodiazepines cautiously, and only if there is an antidote close by. Also patients above the age of 60 are preferred to give other agents like propofol which leave the body much quicker, provided there blood pressure is normal.
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