د .علي كاظم الحيدر
Dr. Ali KadhimLec. ( 2 )
Fluid Balance
Fluid intake : derived from 2 sources :
- Exogenous : 2 – 3 liters per day .
Water from beverage 1200 ml
Water from solid food 1000 ml .
- Endogenous from oxidation of ingested food . 300 – 500 ml / day .
Fluid output
via the urine 1500 mlvia the lungs about 400 ml / insensible losses
via the skin about 500 ml / insensible losses .
via faces 100 ml .
Infants and children requirement much more than the adults because of larger surface area and increased metabolic activity .
Water depletion :
Due to diminished intake because of lack of availability or inability to swallow ( painful mouth and pharynx diseases ) or due to esophageal obstruction . Also tracheotomy causes pure water depletion .Clinical features ( c.f. ) , weakness and intense thirst . Urine output is diminished and specific gravity is increased .
Water intoxication :
either due to excessive a mounts of water or low-sodium or hypotonic solutions are taken by any route . Common cause after operations in the use of excess 5% glucose solutions , colorectal washouts with plain water , instead of saline during total bowel wash-through prior to colonic surgery also during transurethral resection of the prostate ( TURP ) from irrigation fluid .Another cause ( SIADH ) : Syndrome of inappropriate antidiuretic hormone secretion occurs with lung cancer , empyema , lober pneumonia and head injury .
C. features : drowsiness , weakness , s.t. convulsions and coma , nausea and vomiting .
Lab. Investigations show decrease haematocrit , serum sodium and other electrolytes .Treatment :
Water restriction , if no response transfer the patient to the intensive care unit ( ICU ) for more monitoring and control the use of diuretics should be with reservation .Electrolyte Balance :
Sodium balance : ( serum sodium 137 – 147 mmol/lit )Total body sodium about 5000 mmol . , sodium imbalance is a cause of surgical disaster . Limit sodium input after surgery . Sodium is under the control of adrenal corticoid hormone ( Aldosterone is powerful conserver )
Sodium depletion ( hyponatraemia )
Causes : - Intestinal obstruction due to vomiting or aspiration .
- Fistulae ( external ) : duodinal , biliary , pancretric , jejunal )
- Severe diarrhea ( dysentery , cholera , ulcerative colitis )
- SIADH
- Post-operative fluid therapy .
Clinical features :
Sunken eyes and the face is drawn .The tongue is coated and dry .
In infants , the anterior fontanelle is depressed .
The skin is dry and wrinkled .
Peripheral veins are contracted with dark blood .
Urine is scanty with increased specific gravity .
Decreased blood pressure .
Lab. : investigations : normal or low S. sodium with decrease urine output and increase sodium loss .
Sodium Excess ( hypernatraemia )
The major cause is to give much 0.9% saline solution ( I.V. ) in the early postoperative period .Clinical features :
Slight face puffiness .
Pitting oedema ( sacrum ) .
Increase body wt.
Signs of over hydration in infancy ( tense fontanelle odema , increase w.t. much urination ) .
Potassium balance : ( Serum k 3.5 – 5.3 mmol / lit. )
Intracellular cation and mainly present in the skeletal muscles .Potassium depletion :
After trauma , there is increase renal excretion of potassium , also after surgery . Sudden hypokalaemia occurs in patients with diabetic coma treated with insulin and saline solutions .Gradual hypokalamia occurs after surgery in patients using diuretics .
Diarrhea due to ulcerative colitis and villous tumours of the rectum and external fistulae of G.I.T are causes of hypokalamia .
Another cause : prolonged gastro duodenal aspiration , also it common after the post operative period after bowel resection .
Clinical features :
Increased risk of cardiac arrhythmias , severe hypok . may cause slurred speech , muscular speech , muscular hypotonia , depressed reflexes and abdominal distension due to paralytic ileus . weakness of respiratory muscles.Diagnosis : by S. potassium level and ECG ( shows prolonged GT interval and ST depression with T wave inversion ) .
Treatment :
Food rich in K like milk , meat , fruit honey .Oral potassium chloride tablets .
Severe hypokalamia indicate slow intravenous K in fluid therapy under ECG control and daily checking with good urine output .
Potassium deficit can be restarted by adding 40 mmol of KCL to each litre of 5% glucose , glucose – saline or 0.9 % normal saline , should be given 6 or 8 hourly .