د .علي كاظم الحيدر Dr. Ali Kadhim Lec. ( 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 ml via 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 . Calcium : ( serum level 2.2 – 2.6 mmol / lit ) . Serum level modified by ( affected ) . vit. D. , paracthromone hormone , calcitonin , renal and bowel functions hypocalcemia can be treated by oral calcium gluconate and if severe we use I.V. calcium glucorate 10% slowly or with I.V. fluid .