<s>[INST] My fathering 84 and was diagnosed with COPD. He sleeps about 15 hours a day and is beginning to be confused about daily things such as what day it is, where he is supposed to be going etc. He is also continuously cold and has tingling in his hands. His doctor says he doesnt need oxygen but it sounds like CO2 retention to me. An advice? [/INST] Hello I have gone through your question and understand your concern. COPD patients often suffer with hypercarbia that is CO2 retention. Let me explain to you the cause of symptoms in brief for better understanding. Due to decreased alveolar function (lung function) from COPD carbon dioxide is retained in body leading to increased CO2 in blood. Once the CO2 levels increases, blood starts binding more to CO2 than oxygen and thus pH of blood changes to acidic leading to respiratory acidosis. Decreased oxygenation to tissue leads to poor tissue function causing mental confusion, tremors, slow breathing and eventually causes permanent damage to vital tissues like brain. This may lead to coma or sudden death due to respiratory failure. Oxygenation along with monitoring of vitals with regular arterial blood gas test is necessary for patients going into symptoms of CO2 retention. Kindly seek medical help, you may even consider setting up oxygen line and supply at home for patients with COPD. Good luck. Hope your concern is answered. Thank you. </s>