Administration of medications to reduce consciousness or induce sleep in patients suffering from refractory symptoms that are difficult to control is becoming more common in the palliative care setting, particularly in the end-of-life care. Palliative sedation refers to the intentional administration of medications that reduce the patient’s level of consciousness in situations where death is imminent (hours to days) in order to relieve their intolerable and intractable suffering. It involves the use of appropriate, carefully selected and dosed medications, and it is aimed at relieving suffering and not ending the patient’s life.
From the Canadian legal and ethical standpoints, medical practitioners have the obligation to offer or use palliative sedation in justified situations, when the patient’s suffering is intolerable and symptoms are refractory. This responsibility is often neglected either for fear of being accused of shortening the patient’s life, when palliative sedation is confused with euthanasia, or due to the lack of skills in administering sedation. Nevertheless, palliative sedation may have 2 kinds of effects: beneficial, of relieving refractory symptoms, and adverse, as deep sedation makes it impossible for patients to communicate, maintain interpersonal contacts, eat, or drink, and this may potentially contribute to an unintended shortening of their life if no artificial nutrition or hydration is offered.
Palliative sedation is distinct and different from euthanasia or physician-assisted suicide. The intent in palliative sedation is to provide comfort to a patient who has not responded to therapies that allow them to be awake, alert, and comfortable. The intent in euthanasia and physician-assisted suicide is to end a person’s life. In much of the world, including Canada, euthanasia and physician-assisted suicide is not legal. Palliative sedation is legal and can be performed in hospital and outpatient settings with the right family and nursing support.
Indications for sedation in palliative care:
1) Relief of distressing and intolerable symptoms that are refractory to all other forms of treatment. Such symptoms may include dyspnea, anxiety or panic attacks, agitated delirium, pain, persistent nausea and hiccups, myoclonus, or seizures.
2) Brief painful procedures: Insertion of a central venous catheter or an epidural catheter, some nursing interventions (eg, related to pressure ulcers).
1. The decision to administer sedation should be preceded by a thorough clinical assessment, which includes the patient’s general clinical status, possible alternative therapies, and reversibility of symptoms.
2. In competent and conscious patients, informed consent must be obtained. This requires holding a frank discussion with the patient to explain the aims and methods used in sedation. It is important to make the patient aware that sedation impairs consciousness, induces deep sleep (making communication with family or caregivers impossible), prohibits any involvement in making decisions or in preparations for the end of life, and may shorten their life. Any decisions around other aspects of care, such as artificial hydration or nutrition, have to be made prior to initiating sedation. Goals of care have to be focused on comfort, and do-not-resuscitate (DNR) and allow-natural-death (AND) orders have to be documented on the chart. The patient should be aware of imminent death and have the opportunity to say goodbye to family or caregivers before sedation is instituted. If the patient’s condition makes obtaining an informed consent impossible, the consent should be sought from a substitute decision-maker (SDM), such as the family or an appointed power of attorney, who needs to be fully aware of the consequences of sedation. If the patient requires urgent suppression of consciousness (in case of a massive hemorrhage or choking/respiratory distress), sedation may be used for the immediate relief of suffering without the consent of the patient, family, or caregivers.
3. It is recommended that all patients being considered for palliative sedation have a consultation with a palliative care physician to ensure that all possible treatment strategies have been tried prior to initiation of sedation. The administration of palliative sedation should be guided by a physician experienced in this procedure. This is typically a palliative care physician, anesthesiologist, or critical care physician.
4. Pain management should be continued (usually with opioids [see Pain Management: Basic Principles]) throughout sedation.
5. Sedatives are administered in a continuous IV or continuous subcutaneous infusion or via repeated injections (every 4 hours and as needed) to maintain sedation.
6. Sedation should be assessed as needed, usually several times a day but at least daily. Particular focus should be paid to the depth of sedation (the patient being roused by painful stimuli) and effectiveness (presence of distressing symptoms). The goal of sedation with any medication is to ensure comfort. There is usually no need for routine administration of oxygen, monitoring oxygen saturation (SaO2), or routine vital sign checks.
1. Midazolam: A short-acting benzodiazepine with sedative, anxiolytic, hypnotic, and skeletal muscle relaxing properties. Start with an IV or subcutaneous injection of 0.25 to 1 mg followed by a continuous infusion at the rate of 0.25 to 1 mg/h (or higher if needed). Higher initial doses (2.5-5 mg) may be needed in severely distressed patients (such as those with agitated delirium). Patients who have been receiving benzodiazepines prior to initiation of sedation should start at doses at least equivalent to their baseline dose. The onset of action is within 1 to 3 minutes (IV) or 10 to 15 minutes (subcutaneous administration). The duration of action is 15 to 30 minutes after discontinuation of infusion. Depending on dose and infusion rate, midazolam may lead to central respiratory depression, particularly when used in combination with opioids. The duration of action may be markedly prolonged with repeated intermittent injections.
2. Methotrimeprazine: A sedating neuroleptic useful for agitated delirium. The initial dose is 6.25 to 12.5 mg in subcutaneous injections every 8 hours and then as needed; the dose may need to be titrated up to 25 to 50 mg. The agent suppresses nausea and vomiting and may have weak analgesic properties, but it also lowers the seizure threshold and has potential extrapyramidal adverse effects.
3. Phenobarbital: A sedating anticonvulsant useful for all types of seizures and as a third-line sedating agent. Doses range between 30 and 120 mg subcutaneously every 8 to 12 hours and then as needed.
4. Propofol: An anesthetic agent recommended in patients not responding to other therapies. Propofol should be used in the hospital setting only (in many hospitals it can be used exclusively in critical care areas). Initial doses of 2.5 to 5 mg are administered every 90 seconds to 2 minutes and followed by a continuous IV infusion at the rate of 10 to 70 mg/h. The onset of action is within several seconds and duration of action is 2 to 3 minutes. Propofol also suppresses vomiting and hiccups.
5. Haloperidol: Haloperidol may be used in addition to midazolam for delirium and nausea or emesis. The initial doses are 0.5 to 2 mg in subcutaneous intermittent injections every 4 to 6 hours. Haloperidol is not recommended as a single agent for palliative sedation as it is not a sedating neuroleptic and with high doses potentially increases the risk of extrapyramidal adverse effects.
Opioids should not be used for sedation. While it is important to initiate and continue them along with sedatives to ensure comfort and analgesia, opioids are not appropriate as the single agent for inducing palliative sedation as sedating doses cause many adverse effects.