November 2002

Dear Readers: Here's the Article for this Month:

Name of article:

Delirium and dehydration: some fluid for thought?

Author(s): Peter G. Lawlor

Reference: Support Care Cancer 2002; 10: 445-454

Abstract:

The Author shows us delirium in all its complexity as a heterogenous neuro-psychiatric syndrome, as a frequent complication in advanced cancer patients (28-40% on admission to institutional care and most patients in their last hours/days of life) and as a distressing symptom both for the patient as well as the family and the health care staff.

In the revision, the etiology and pathophysiology of delirium is amply dealt with, as well as its clinical manifestations and the importance of early diagnosis and assessment.

However, the aim of Lawlor’s paper, is to examine the association between the prevention and the treatment of delirium and assisted (artificial) hydration, according to the recent data of the literature.

In order to let us understand whether to hydrate the patient, how much fluid to administer daily and through which administration route (intravenous, enteral, subcutaneous, rectal), the Author describes the homeostatic mechanisms of fluid balance, the pathophysiology and pathogenesis of the fluid deficit state and the assessment of such deficit.

As the administration of high doses of opioid analgesics and the reduced renal elimination of them or of their metabolites can cause neurotoxicity (delirium, myoclonus, hyperalgesia, allodynia and even seizures), the association between administration of the different types of opioids, the fluid balance and the pathogenesis of delirium is reported.

Data of literature show a link between delirium and dehydration but the relative proportions of "cause" and "effect" to be attributed to fluid deficit are not often clear.

How and when to decide if assisted hydration is appropriate or not in the treatment of delirium?

The decisional process is often difficult and comprises scientific evidence, ethical issues and the communication with the cognitively intact patients and/or their family.

Although the studies carried out in cancer patients and in the elderly population show that the artificial hydration plays a role in contributing towards the prevention, the onset and development of delirium, the informed consent of the patient and/or the family will result in an ethical and individualized approach regarding the appropriate use of assisted hydration.

Because delirium is a multifactorial symptom, assisted hydration associated with other therapeutical interventions (opioid switching, reduced opioid dose, haloperidol administration) are highly recommended.

The type of fluid to administer depends on the sodium and water depletion and the quantity of fluid is indicated as being 1 litre/day. The administration route of the fluids must be personalized also taking into account the setting of care.

In the patients without a central venous catheter or without a nasogastric tube, the administration via hypodermoclysis (continuous subcutaneous infusion) is simple and highly recommended.

Why I chose this Article:

The role of assisted hydration is still controversial in the Palliative Care setting.

Over the years, we have passed from an aggressive "hospital model" where, from the birth to the death and in any stage of the oncological disease, the patient was artificially hydrated.

The "hospice model" recommends a conservative approach where assisted hydration is not used in terminal cancer patients because it is considered unnecessary, distressing and uncomfortable for the patients. The "individualized model" shows the way of a tailored-approach, individualized for each single patient, where, assisted hydration, is delivered in a comprehensive management of the symptoms referred by the patients, taking into account the stage of the disease, the clinical conditions and the ethical issues.

As regards the prevention and the treatment of delirium, the assisted hydration plays its role in association with other therapeutical interventions.

Regards,

Carla Ripamonti, MD
Member of the Board of Directors, IAHPC