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Electrolyte and Fluid Imbalance: Introduction

​Overview and Implications

Electrolyte and Fluid Imbalance

Many adult hospital inpatients require intravenous (IV) fluid therapy to prevent or correct problems with their fluid and/or electrolyte status. This may be because they cannot meet their normal needs through oral or enteral routes (related for example to swallowing problems or gastrointestinal dysfunction) or because they have unusual fluid and/or electrolyte deficits or demands caused by illness or injury (e.g., high gastrointestinal or renal losses). Deciding on the optimal amount and composition of IV fluids and the best rate at which to administer them can be a difficult task. Decisions must be based on careful assessment of the patient's individual needs (National Institute for Health and Care Excellence (NICE) 2013).

Although mismanagement of fluid therapy is rarely reported as being responsible for patient harm, it is likely that as many as one in five patients who receive intravenous (IV) fluids and electrolytes suffer complications or morbidity due to their inappropriate administration. (National Institute for Health and Care Excellence (NICE) 2013/2017),

Potential complications of fluid and electrolyte therapy include:

  • hyponatremia,
  • hypernatremia 
  • hypokalemia
  • hyperkalemia
  • hyperchloraemic acidosis
  • volume overload
  • volume depletion (NICE 2013)

Hospitalized patients require intravenous (IV) fluid and electrolytes for one or more of the following reasons (the 4Rs):

  • Fluid resuscitation 
  • Routine maintenance 
  • Replacement 
  • Redistribution (NICE 2013/2017)

Despite the almost ubiquitous need for, and use of intravenous fluids in acutely ill patients, there has been little consensus on the most appropriate rate of administration and composition of intravenous fluids, and practice patterns with respect to maintenance fluids vary widely (Moritz & Ayus 2015).

According to NICE (2013/2017) the principles underpinning safe and effective IV fluid and electrolyte therapy are: 

  • physiological principles that underpin fluid prescribing
  • pathophysiological changes that affect fluid balance in disease states
  • indications for IV fluid therapy
  • reasons for the choice of the various fluids available and
  • principles of assessing fluid balance

Fluid overload

Fluid overload is a relatively frequent occurrence in critically ill patients and is often a consequence of critical care intervention. It may lead to pulmonary edema and in critically ill patients, fluid overload is independently associated with increased morbidity and mortality as well as increased hospital costs (NICE 2013; Ogbu et al. 2015).

Transfusion-associated circulatory overload (TACO)

TACO is a complication of blood transfusion that is due to impaired cardiac function and/or an excessively rapid rate of transfusion. It occurs in one in 700 transfusion recipients and patients over 70 years of age, infants, and patients with severe euvolemic anemia (hemoglobin <50 g/L), renal impairment, fluid overload, and cardiac dysfunction are particularly susceptible (Callum et al. 2016). The risk factors for TACO include, age over 70 years, history of heart failure, left ventricular dysfunction, history of myocardial infarction, renal dysfunction, and positive fluid balance.  The clinical presentation includes: dyspnea, orthopnea, cyanosis, tachycardia, increased venous pressure and hypertension (Callum et al. 2016).

Hypovolemic shock

In hypovolemia, a patient's fluid needs are not met by oral, enteral or IV intake and the patient will demonstrate features of dehydration on clinical exam, low urine output or concentrated urine and biochemical indicators, such as more than 50 per cent increase in urea or creatinine with no other identifiable cause (NICE, 2013). Patients may exhibit thirst, vomiting, diarrhea, weight loss, dizziness, confusion, somnolence, reduced skin turgor, dry mucous membranes, sunken eyes, reduced capillary refill, tachycardia and postural hypotension (Frost 2015). Hypovolemic shock is an emergency condition in which severe blood and fluid loss make the heart unable to pump enough blood to the body.


Reduce the incidence of harm associated with electrolyte and fluid imbalance. 

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Hospital Harm Measure

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Hospital Harm Measure

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