Question: If one who rejects use of a ventilator (e.g. upon contracting COVID-19) dies later, is this considered as taking one’s life?
Answer: What this question is asking for is a simple ‘yes’ or ‘no’ answer. However, as real life is complex, the actual answer that depends on specific conditions, would hinge upon the following considerations.
 If there is a relatively higher chance of recovery with use of a ventilator, to not use it is unwise, in principle similar to indirect or eventual suicide, thus breaking the First Precept. This is so as it endangers one’s life needlessly. (e.g. Many COVID-19 patients do recover with use of ventilators, along with other medical methods.)
 If there is fear or dread of uncomfortable and indefinite intubation, it should be noted that depending on one’s condition, not all ventilator usage requires intubation, thus not necessarily being invasive in nature. (The above picture is an example.)
 If there is intubation for ventilation, it does not always mean that it will definitely be for the rest of one’s life, or that there is no more hope of long-term survival. According to a study on ‘The Long-Term Survival of  Successfully Weaned Prolonged Mechanical Ventilation Patients’, ‘The 1-, 2-, 3-, 4- and 5-year survival rates of successfully weaned PMV (Prolonged Mechanical Ventilation) patients were 32.5%, 28.0%, 24.9%, 23.9%, and 21.3%, respectively.’
 Only when there is relatively lower chance of meaningful recovery, with death possibly or highly imminent, while creating needless pain and discomfort, that continually prevents peace of mind for guided practice of mindfulness of Buddha, can there be consideration of rejection of ‘extraordinary’ ways to stay alive. (On recovery possibilities, always consult the qualified doctors in charge.)
 If already on some form of life support (including intubation for ventilation), for example, due to default emergency medical practice, it should be noted that this can ‘buy’ some crucial extra time for sufficient practice, before auspicious departure occurs ‘naturally’. The following related case should be studied carefully before making any rash life or death decision: https://purelanders.com/2021/08/how-my-mother-departed-for-pure-land-smoothly-without-turning-off-life-support.
The above considerations should be openly and detailedly discussed with immediate family members and close friends in ‘peace’ times, in case related medical emergencies do occur.