Saturday, Feb 01, 2014
The Straits Times
By Andy Ho
The National University of Singapore medical school just launched an online casebook about ethical dilemmas that doctors face, including end-of-life issues, which have been on my mind a lot lately.
My mother passed away at 81 less than two weeks ago from end-stage adenocarcinoma of the lung.
Diagnosed 14 months earlier, she was virtually symptom-free for the first 13 months. So she did quite well considering also that the median survival time for such cases is about 8 months.
Locally, lung cancer is the third most common malignancy in women. And the adenocarcinoma variety is the most common form of lung cancer in women, often non-smokers like my mother.
Because the adenocarcinoma often begins in the outer parts of the lungs, symptoms like cough, shortness of breath and blood in the sputum are not common: my mother never had them.
She stayed active and independent until the final month of her life when the cancer started producing the antidiuretic hormone (ADH). In health, it is the pituitary gland in the brain that produces ADH, which normally maintains the delicate balance of water and salt in the body.
When a cancer itself starts producing ADH - this is called the syndrome of inappropriate antidiuretic hormone (SIADH) production - it upsets the body's delicate balance of water and salt. In SIADH, the kidneys stop producing urine, so the body retains too much water and does not have enough salt. At this point, the patient becomes weak, confused, delirious and may fall into a coma.
Because the body retains water excessively in SIADH, the patient is not allowed liquids. At this point, I asked if my very delirious and distressed mother could be sedated continuously until death.
This is called continuous deep sedation (CDS), during which fluids are concurrently discontinued. even if there is no SIADH.
My mother had, on several previous occasions, expressed her wish to many of us separately that she wanted to suffer as little as possible. Hence my request for CDS, to render her unconscious until she died.
But CDS is controversial the world over. A 2013 University of Chicago survey found that 10 per cent of US doctors have carried out the procedure before.
The idea is to make the dying patient - with intractable suffering that cannot be alleviated despite optimal treatment - go into deep sleep. However, in sedating the patient to unconsciousness, the doctor must avoid using so much of the sedative that the patient stops breathing, which might be construed as active euthanasia.
The balancing act is required because the drugs that induce and maintain deep sleep can also suppress the brain centre that controls our automatic breathing. That is, CDS may hasten death unintentionally. But it is still permissible under the doctrine of double effect.
Originally developed in Roman Catholic theology, this doctrine states that an action is morally permissible even though it may also lead to serious harm, such as the death of a human being, because it does much good.
Thus, some consider CDS to be ethically permissible, since sedation for the delirious is par for the course anyway and, used for the dying, can offer much comfort.
However, CDS may also be accompanied by the withholding of hydration, which would make it look like euthanasia by stealth.
The reason given for withholding fluids in CDS is always that it is common practice in palliative care not to rehydrate dying patients. Also, withholding fluids causes them no symptoms of suffering that can be discerned, save for a dry mouth, it is said. It is also claimed that, under the circumstances, fluid withdrawal does not quicken death anyway.
But most family members would beg to differ: water is needed for life, so how could withholding fluids benefit the dying? It certainly can't make the patient more comfortable, one feels.
Some argue, though, that as the body's systems begin shutting down with death approaching in the very ill, the kidneys can no longer excrete the additional fluid that an intravenous (IV) drip delivers. That fluid could pool in the lungs, causing the patient difficulty in breathing, it is argued.
While there is a medical consensus that appropriate sedation does not shorten life per se, there is vigorous disagreement over whether fluids should be concurrently withheld in CDS.
It seems more prudent not to assume that a dangerously ill patient who does not receive hydration should feel no thirst.
In fact, one should assume that she experiences thirst - unless disease has destroyed the centre for thirst (in the part of the brain called the hypothalamus).
Retrospective studies of hydration and thirst in the dying have produced data that is hard to interpret, especially in patients dying of lung cancer with SIADH, like my late mother.
But it would be unethical to do prospective studies on the issue, which would require the random assignment of some dying patients to fluid withdrawal and others to artificial hydration by IV drip, when it is their comfort that should be uppermost.
Therefore, many doctors would set up drips for such hospitalised patients if they can no longer drink (unless there is SIADH).
Clearly, scientists don't yet have a firm grasp of the benefits and harms of dehydration or rehydration in this situation, so clinicians will continue to manage terminal hydration in ways that they are personally comfortable with.
Experience in palliative care - in hospice rather than hospital settings usually - supports the view that most patients with death imminent do die in comfort without drips. But it is hard to believe that they are not also thirsty. Perhaps, being semi-conscious or unconscious on CDS, they just can't communicate their thirst.
Mercifully, my mother passed away in her sleep before a decision on CDS was made for her.
But it still remains for the profession to discuss the issue and come to a consensus on CDS for the terminally ill and also whether it should be accompanied by dehydration or rehydration.