Steve Jobs died of respiratory arrest caused by pancreatic tumor at about 3 p.m. on Oct. 5 at his home in Palo Alto, Calif., his death certificate revealed. His occupation was filed as entrepreneur in high tech business.

In the document issued by the Santa Clara County Public Health Department in San Jose and obtained by Bloomberg, respiratory arrest was listed as the immediate cause of death, with metastatic pancreas neuroendocrine tumor as the underlying cause. No autopsy was performed.

Respiratory arrest in cancer patients isn't uncommon, even though in many cases it is not the cancer, but the medication used in relieving the cancer pain that results in the cessation of breathing.

Palliative care or pain management involving potentially harmful drugs such as opioids often exhibit side effects of hastening death by causing respiratory depression, according to a paper published by the International Association for Hospice and Palliative Care.

Respiratory depression is potentially life threatening, and it is considered the most serious opioid side effect and is of great concern to physicians and nurses. Opioids can depress both the rate and depth of respiration, says the paper.

However, opioids, including morphine, are used extensively in managing the unbearable pain that is common in cancer patients even when studies have shown that these pain relievers hasten death.

The principle of double effect is used to justify the administration of medication to relieve pain even though it may lead to the unintended, although foreseen, consequence of hastening death by causing respiratory depression, the paper explains the ethical and moral feasibility of pain medication.

Conversely, a considerable number of cancer patients are undertreated for pain, due to the ethically questionable status of the standard pain-killing procedure using opiates.

Walter Issacson, author of Jobs' authorized biography, had said that Jobs was in severe pain weeks prior to his death and was unable to climb the stairs of his house.

Palliative care medication is a comfort mechanism and enables terminally ill patients to spend their last hours with their family and loved ones and ensures a painless death.

None of Jobs' family members or Apple representatives have issued a statement regarding the cause of Jobs' death.