fluid balance

fluid balance

1. FLUID BALANCE S.YASITHA

2. OBJECTIVES Define Fluid balance Fluid distribution Fluid intake Fluid output Factors affecting fluid balance Problems of fluid balance Fluid balance assessment

3. INTRODUCTION FLUIDS: Water is the substantial proportion of the body weight. In fact, about 60% of the body weight of an adult man is water. Women typically have less water than men. The fluid means water that contains dissolved or suspended substances such as glucose ,mineral salts and proteins.

4. FLUID DISTRIBUITION:

5. MOVEMENT OF FLUIDS Fluid circulates between compartments by diffusion . This is “the random movement of particles from regions where they are highly concentrated to areas of low concentration. Movement continues until the concentration is equally distributed”. This is normally a passive process but it can be facilitated by a carrier molecule , usually a specialist protein. Fluid also moves by osmosis , defined by Montague et al as “the flow of water across a semipermeable membrane from a dilute solution to a more concentrated solution until stability is reached”.

6. FLUID BALANCE DEFINITION: Fluid homeostasis is the dynamic interplay of three process: - Fluid intake and absorption - Fluid distribution - Fluid output To maintain fluid balance, fluid intake must be equal to fluid output. -Because some of the normal daily fluid output [ e.g., urine, sweat] is a hypotonic salt solution, people must have equivalent fluid intake of hypotonic sodium-containing fluid [water plus foods with some salt] to maintain fluid balance [intake =output]

7. FLUID INTAKE: Fluid intake occurs orally through drinking but also through eating because most foods contain some water . Food metabolism creates additional water. Average fluid intake from these routes for healthy adults is about 2300ml, this amount can vary widely, depending on exercise habits, preferences and the environment. Other routes of fluid intake includes IV, rectal [e.g., enemas] and irrigation of body cavities that can absorb fluid.

8. REGULATION OF FLUID INPUT: Plasma Osmolality - most important regulator -controls the water balance by stimulating thirst centre and antidiuretic hormone [ADH] secretion through osmoreceptors situated in hypothalamus. Blood Volume - A change in blood volume is detected by volume receptors present in atria. When blood volume is low, impulses is sent to the hypothalamus and pituitary to secrete ADH. -This cause conservation of water by kidneys.

9. FLUID OUtPUT : Fluid output normally occurs through four organs the skin, lungs, gastrointestinal [GI] tract and kidneys. Examples of abnormal fluid output include vomiting, wound drainage or hemorrhage. Insensible [not visible] loss of water is through the skin and lungs which is continuous. It increases when a person has fever or a recent burn to the skin. Sweat, which is visible and contain sodium, occurs intermittently and increases fluid output substantially.

10. REGULATION OF FLUID OUTPUT: Kidney -major regulator -they respond to hormones that influence urine production. Drinking of water is necessary since there is obligatory water loses due to insensible water loses[ through skin]. The GI tract plays vital role in fluid balance. Approximately 3 to 6L of fluid moves into the GI tract daily and returns to the ECF. The average adult normally excretes only 100ml of fluid each day through feces. However diarrhea cause large fluid output.

11. NORMAL [PER DAY] PROLONGED HEAVY EXERCISE[PER HOUR] FLUID INTAKE[Fluid ingested] Oral 1100-1400 ml 280-1100 ml/ hr Foods 800-1000 ml Highly variable Metabolism 300 ml 16-50 ml/ hr TOTAL 2200-2700 ml 300-1150 ml/ hr FLUID OUTPUT Skin[insensible and sweat] 500-600 ml 300-2100 ml/ hr Insensible lungs 400 ml 20 ml/ hr Gastrointestinal 100-200 ml Negligible, unless diarrhea during exercise Urine 1200-1500 ml 20-100 ml/ hr , depending on hydration status TOTAL 2200-2700 ml 340-3120 ml/ hr Rehydration with Na+ containing fluid necessary after prolonged vigorous exercise HEALTHY ADULT AVERAGE FLUID INTAKE AND OUTPUT

12. Factors affecting fluid balance: Lifestyle factors: - Nutrition -Exercise -Stress Physiological factors: -Cardiovascular -Respiratory -Gastrointestinal -Renal -Integumentary -Trauma

13. Developmental factors: -Infants and children -Adolescents and middle-aged adults - Older adults Clinical factors: -Surgery -Chemotherapy -Medications -Gastrointestinal intubation -Intravenous therapy

14. PROBLEMS OF FLUID BALANCE EXCESS OF FLUID VOLUME -Hypervolemia -Water intoxication DEFICIENT OF FLUID VOLUME -Hypovolemia -Dehydration

15. Why it is important to maintain fluid balance in the body? Maintenance of an adequate fluid balance is vital to health. Inadequate fluid intake or excessive fluid loss can lead to dehydration, which in turn can affect cardiac and renal function and electrolyte management. Inadequate urine production can lead to volume overload, renal failure and electrolyte toxicity.

16. FLUID ASSESSMENT Scales and Pilsworth identified three elements to assess fluid balance and hydration status. They are; -Clinical assessment -Review of fluid balance charts -Review of blood chemistry Clinical assessment -The elasticity of skin, or turgor, is an indicator of fluid status in most patients. -Assessing skin turgor is a quick and simple test performed by pinching a fold of skin. - In well hydrated person, the skin will immediately fall back to its normal position when released. Fluid balance charts -Monitoring a patient’s fluid balance to prevent dehydration or overhydration is a relatively simple task, but fluid balance recording is notorious for being inadequately or inaccurately completed.

17. Blood chemistry The analysis of blood chemistry may be useful in the assessment of hydration status, the evidence surrounding this is equivocal. According to Wolfson , sodium, potassium, chloride, bicarbonate, blood urea nitrogen (BUN) are helpful blood electrolytes to measure when determining hydration status. Importance of fluid balance chart The aim of a fluid balance charts is to keep an accurate record of a patients fluid input and output and to identify any deficiency in their body.

18. SUMMARY Fluid balance is the balance of the input and output of fluids in the body to allow metabolic processes to function To assess fluid balance, nurses need to know about fluid compartments in the body and how fluid moves between these compartments Dehydration is defined as a 1% or greater loss of body mass as a result of fluid loss. Symptoms include impaired cognitive function, headaches, fatigue and dry skin. Severe dehydration can lead to hypovolemic shock, organ failure and death. The three elements to assessing fluid balance and hydration status are: clinical assessment, body weight and urine output; review of fluid balance charts and review of blood chemistry Fluid balance recording is often inadequate or inaccurate often because of staff shortages, lack of training or lack of time.

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