Evaluation and treatment of cancer-related fluid deficits: volume depletion and dehydration

Abstract

Fluid deficits should be divided into two categories (dehydration and volume depletion) according to pathophysiology and into 3 categories (hyponatremic, hypernatremic, and isotonic) according to the plasma sodium concentration. Dehydration (total water deficit especially intracellular) is always hypernatremic, while volume depletion (intravascular water and sodium deficit) is either hyponatremic, hypernatremic, or isotonic. There are no clear clinical differences among the various categories, but a delay of capillary refill, tachycardia, and orthostatic hypotension are more common with early volume depletion. An Evans blue and mannitol test can be used to distinguish between hypernatremic volume depletion and dehydration. Careful clinical assessment and laboratory tests (especially serum sodium) are the key to diagnosis and effective management. According to the type (hypernatremic, hyponatremic, or isotonic), severity of fluid deficit, and associated symptoms, oral or parenteral fluid should be given along with treatment of the underlying cause. In hemodynamically compromised individuals with orthostatic hypotension and oliguria, replacement with isotonic saline until hemodynamic stabilization is crucial. Terminal hydration is still controversial. Important ethical principles govern clinical decision-making about hydration at the end of life.

Delirium and dehydration: some fluid for thought?

“…The general use of the term 'dehydration' to mean volume depletion and hypovolemia as well is erroneous, even though each of these is also associated with a fluid deficit state [60,63,92]. Dehydration refers specifically to a deficit in total body water, which affects the intracellular and interstitial spaces.…”

“…The high risk of fluid deficit in this population is well recognized [21,47,53,94,108], especially in the presence of one or more of the factors listed in Table 3. Even the process of water restriction prior to laboratory procedures has been suggested as a risk factor [92]. A study of elderly patients suggested that female gender, age over 85 years old, presence of more than four chronic medical conditions or acute diagnoses, use of more than four medications, use of laxatives, and bedridden status were all associated with biochemical markers of fluid deficit (sodium levels greater than 150 mmol/l, or blood urea nitrogen/creatinine ratio greater than 25) [53].…”

“…Formulae designed for estimation of the deficit are often of limited use in advanced disease, and as their discussion is beyond the scope of this review the reader is referred to other texts [91,92]. A number of potential explanations have been proposed for the general finding that lower hydration volumes are needed in patients with advanced cancer than in the general medical population [98].…”

Artificial nutrition and hydration in terminal cancer patients: the real and the ideal

“…Thus, these issues remain a room for debates. Physicians are still confused when they are faced with this problem [13][14][15][16][17][18]. For example, according to the study of Tatsuya Marita et al [19], 72% of Japanese physicians believe that it is difficult to adequately determine the medical indications for intravenous hydration.…”

Health effects of desalinated water: Role of electrolyte disturbance in cancer development

“…Many patients with cancer do not fit this physiological pattern (healthy individual phenotype). On the contrary, most patients with cancer suffer from hyponatremia rather than hypernatremia, due to low sodium and serum osmolality (Sarhill et al, 2001;Davis et al, 2009;Nwosu et al, 2013). In many instances, the cancer is accompanied by the syndrome of inappropriate antidiuresis (SIADH).…”