fluid&electrolyte balance

FLUID,ELECTROLYTE AND ACID FLUID,ELECTROLYTE AND ACID FLUID,ELECTROLYTE AND ACID FLUID,ELECTROLYTE AND ACID

BASE BALANCEBASE BALANCEBASE BALANCEBASE BALANCE

FLUID,ELECTROLYTE AND ACID BASE BALANCE

� FLUID IN TAKE :

1) EXOGENOUS – 2 to 3 Litres /24 Hours

WATER REQUIREMENTS OF INFANTS AND CHILDREN ARE RELATIVELY GREATER THAN THOSE OF ADULTS BECAUSE OF

� THE LARGER SURFACE AREA PER UNIT OF BODY WEIGHT THE GREATER METABOLIC ACTIVITY DUE TO GROWTH � THE COMPARATIVELY POOR CONCENTRATING ABILITY OF THE IMMATURE

KIDNEY 2) ENDOGENOUS - Normally Less than 500ml/24 Hour. IT IS RELEASED DURING THE OXIDATION OF INGESTED FOOD. HOWEVER DURING STARVATION,THIS AMOUNT IS SUPLEMENTED BY

WATER RELEASED FROM THE BREAKDOWN OF BODY TISSUES.

FLUID OUT PUT :

LUNGS – 400ml / 24 Hours SKIN – 600ml to 1000ml / 24Hrs FAECES – 60 to 150ml / 24 Hrs URINE – Approx.1500ml 24Hrs

OLIGURIA – >300 ml / 24 Hours ANURIA – Complete absence of Urine

WATER DEPLETION : DIMINSHED INTAKE

PURE WATER DEPLETION

� CLINICAL FEATURES :

WEAKNESS,INTENSE THIRST, SUNKEN EYES, DRY MUCUS MEMBRANES,DECREASED URINE OUTPUT, LOW PULSE PRESSURE, LOW B.P., CONFUSION.

CVP – Normal 3-8 cm H2O.

�TREATMENT : USING NS OR 5%D SOLUTIONS OR APPROPRIATE WATER REPLACEMENT FORMULAS.

WATER INTOXICATION

� TURP SYNDROME � SIADH : SYNDROME OF INAPPROPIATE ANTIDIURETIC

HORMONE SECRETION � COLORECTAL WASH OUTS WITH PLAIN WATER INSTEAD OF

SALINE CLINICAL FEATURES : DROWSINESS, WEAKNESS,

CONVULSIONS AND COMA. NAUSEA AND VOMITING OF CLEAR FLUID, PASSING LARGE

AMOUNT OF DILUTE URINE. � TREATMENT : STOP INTAKE OF WATER.TRANSFER TO ICU.

TREAT WITH DIURETICS OR HYPERTONIC SALINE. � RAPID CHANGES IN SERUM SODIUM CONCENTRATION –

NEURONAL DEMYELINATION.

WATER BALANCE OF A HEALTHY ADULT(70kg)

INTAKE:

WATER FROM BEVERAGE=1200ml

WATER FROM SOLID FOOD=1000ml

WATER FROM OXIDATION=300ml

OUTPUT:

URINE – 1500ml

SKIN – 500ml

INSENSIBLE LOSS

LUNGS – 400ml

FAECES – 100ml

NORMAL VALUES OF SERUM ELECTROLYES

Na+ - 133 to 144mmol/L

K+ - 3.5 to 5.3mmol/L

Cl- - 90 to 110mmol/L

HCO3- -25mmol/L

Ca+ 8 to 10mg/dl.

SODIUM BALANCE

� SODIUM – PRINCIPAL CATION OF ECF. NORMAL VALUE (SERUM) 133-144 mmol/L

� DAILY INTAKE – AVERAGE 1mmol/kg Nacl or 500ml ISOTONIC 0.9% SALINE SOLUTION.

� CONTROL BY ADRENAL GLANDS.

HYPONATREMIA

SERUM SODIUM < 120mmol/L

CAUSES : BOWEL OBSTRUCTION

FISTULAE VOMITING DIARRHOEA.

CLINICAL FEATURES : CONFUSION, LETHARGY, DISORIENTATION

SEVERE(<120 mmol/L)-SEIZURES, COMA.

TREATMENT

HYPOVOLEMIC HYPONATREMIA :

1) GI FLUID OR BLOOD LOSS - REPLACE VOLUME USING

A CRYSTALLOID(0.9%NaCl or RL) OR A COLLOID.

HYPERVOLEMIC HYPONATREMIA :

1) CHF, CIRROHSIS,NEPHROTIC SYNDROME 2) TREAT THE DISORDER 3) Na RESTRICTION 4) DIURETUICS+WATER RESTRICTION

EUVOLEMIC HYPONATREMIA

1) SIADH

2) WATER RESTRICTION TO <1L/day.

RULE OF THUMB : 1. LIMIT THE CHANGE 1mmol/L OF SODIUM TO HALF OF THE

TOTAL DIFFERENCE IN THE FIRST 24 HRS.

2. RELATIVELY SLOW CORRECTION 0.5mmol/L PER Hour.

RAPID CORRECTION – PONTINE DEMYELINATION.

HYPERNATREMIA CAUSES :

� EUVOLEMIC HYPERNATREMIA (PURE WATER LOSS) SWEATING,FEVER,TACHYPNOEA, DIABETES INSIPIDUS.

� HYPOVOLEMIC HYPERNATREMIA (WATER DEFECIET IN EXCESS OF SODIUM DEFECIET) BURNS, FISTULAS

� HYPERVOLEMIC HYPERNATREMIA (SODIUM GAIN IN EXCESS OF WATER GAIN) EXCESSIVE 0.9% SALINE ADMINISTRATION,ADRENAL HYPER

FUNCTION.

CLINICAL FEATURES SIGNS:

PUFFINES OF THE FACE. PITTING OEDEMA – SACRAL REGION, 4.5 Litres OF EXCESS FLUID.

TREATMENT : HYPOVOLEMIC HYPERNATREMIA RESTORE ECF VOLUME BY 5%D OR 0.45%NS HYPERVOLEMIC HYPERNATREMIA DIURETICS DIALYSIS IN PRESENCE OF RENAL FAILURE EUVOLEMIC HYPERNATREMIA WATER REPLACEMENT WITH 5%D

POTASSIUM BALANCE

� POTASSIUM : NORMAL RANGE 3.5 – 5.3 mmol /L POTASSIUM IS ALMOST

ENTIRLY INTRACELLULAR(98%) NORMAL ADULT GETS 1.0 mmol/kg of K+.

FRUIT,MILK AND HONEY ARE RICH SOURCES.

� POTASSIUM DEPLETION : THE AUGMENTED POTASSIUM EXCRETION OF TRAUMA -

DEGREE OF TISSUE DAMAGE IS DIRECTLY PROPORTIONAL TO LOSS, IS GREATEST DURING THE FIRST 24 HRS AND LASTS FOR 3 OR 4 DAYS.

HYPOKALEMIA REVEALS AFTER 48 HRS.

HYPOKALEMIA

� SUDDEN HYPOKALEMIA : DIABETIC COMA, TREATED BY INSULIN AND PROLONGED INFUSION OF SALINE.

� GRADUAL HYPOKALEMIA : DIURETICS DIARRHOEA IBD VILLOUS TUMOURS EXTERNAL FISTULAE(GI)

CLINICAL FEATURES

� CLINICAL FEATURES : LISTLESSNESS,SLURRED SPEECH,MUSCULAR HYPOTONIA,DEPRESSED REFLEXES,ABDOMINAL DISTENTION(PARALYTIC ILEUS) RAPID SHALLOW RESPIRATION.

� DIAGNOSIS BY ECG : PROLONGED QT INTERVAL,DEPRESSION OF ST SEGMENT,FLATTENGING OR INVERSION OF T WAVE

TREATMENT

TREATMENT : ORAL – MILK,MEAT,FRUIT JUICES,HONEY POTASSIUM CHLORIDE 2G ORALLY 6TH HOURLY.

INTRAVENOUS : RAPID CORRECTION-DYSRHYTHMIAS AND CARDIAC ARREST.

40mmol Kcl to EACH 1 LITRE OF 5% D OR DNS OR 0.9% SALINE - 6 TO 8 HOURLY.

HYPERKALEMIA � HYPERKALEMIA : BRADYCARDIC CARDIAC ARREST

� MAJOR CAUSES : RENAL TUBULAR ACIDOSIS

ADDISON’S DISEASE, CONGESTIVE HEART FAILURE.

� DRUGS : DIGOXIN, AMILORIDE, SPIRINOLACTONE,

TRIMETHOPRIM, NSAIDS, CYCLOSPORINE.

TREATMENT 1. CALCIUM GLUCONATE 10 ml OF 10% SOLUTION OVER 2-3

MIN WHEN K+>6.5

2. INSULIN+GLUCOSE 10 units REGULAR IV+50% DEXTROSE

3. NAHCo3 : 90 mmol(2 ampules IV PUSH OVER 5 MIN)

4. KAYEXALATE+SORBITOL

ORAL 30G WITH 20% SORBITOL RECTAL

50G IN 200ml 20% SORBITAL ENEMA RETAIN 45 MIN

5. FUROSEMIDE : 20-40mg 1V PUSH

6. DIALYSIS

CALCIUM BALANCE

� CALCIUM : EXTRA CELLULAR CATION PLASMA CONCENTRATION OF 2.2-2.5mmol/L(8 to 10mg/dl) IT EXIST IN THREE FORMS 1. BOUND TO PROTIEN 2. FREE NON IONISED 3. FREE IONISED LAST FORM : NECESSARY COMPONENT FOR BLOOD COAGULATION AND FOR AFFECTING THE NEURO

MUSCULAR EXCITABILITY

HYPERCALCEMIA � HYPERCALCEMIA : Ca LEVELS>2.9mmol/L(>11.5mg/dl)

� CLINICAL FEATURES : FATIGUE, DEPRESSION, CONFUSION, ANOREXIA, NAUSEA,

CONSTIPATION, POLYURIA, ARRHYTHMIAS SEVERE HYPERCALCEMIA – 3.7 mmol/L(>15mg/dl) MEDICAL EMERGENCY – COMA AND CARDIAC ARREST

� CAUSES : PARATHYROID ADENOMAS, MEN SYNDROMES, MULTIPLE MYELOMAS,

METASTASES(BREAST Ca), LUNG AND KIDNEY MALIGNANCIES, VITAMIN D INTOXICATION.

BONES, STONES, ABDOMIAL GROANS AND PSYCHIC MOANS

TREATMENT : 1. HYDRATION WITH SALINE(6L/day)

2. FORCED DIURESIS-FUROSEMIDE 4-12hourly ALONG WITH AGGRESSIVE HYDRATION

3. BISPHOSPHONATES-PAMIDRONATE 30-90 mg IV OVER 4 HOURS

4. CALCITONIN-2-8 U/kg IV/IM 6-12 hrs

5. GLUCOCORTICOIDS - PREDINSONE 10-25mg qid

6. MITHRAMYCIN

7. DIALYSIS

HYPOCALCEMIA

� CLINICAL FEATURES : PERIPHERAL AND PERIORAL PARESTHESIA, MUSCLE

SPASMS, CARPOPEDAL SPASMS, LARYNGEAL SPASM, SEIZURES, RESPIRATORY ARREST. TETANY. TROUSSEAU’S SIGN, CHEVOSTEK’S SIGN

� CAUSES : BURNS, SEPSIS, ACUTE RENAL FAILURE, MASSIVE BLOOD

TRANSFUSIONS.

� TREATEMENT : 1. 10ml OF 10% Ca gluconate given over 10 min 2. CALCIUM GLUCONATE IV 20 – 50ml OVER 8 HRS

� HYPOPARATHYROIDISM : Ca+VITAMIN D OR CALCITRIOL

MAGNESIUM

INTRA CELLULAR CATION

NORMAL LEVELS – 0.7 – 0.9mmol/L.

20mmol MAGNESIUM SULPHATE ADDED TO 5% D OR NS SOLUTIONS TO TREAT HYPOMAGNESEMIA.

ACID BASE BALANCE

� PH NORMAL RANGE – 7.35 - 7.45

� PH LOW ACIDOSIS

� PH HIGH ALKALOSIS

� PO2 :-NORMAL VALUE - 80-110 mmHg

� PCO2 :-NORMAL VALUE - 35-45 mmHg

� HCO3 :-NORMAL VALUE - 25 mmol/L

PH

PCO2

HCO3

RESPIRATORY

ACIDOSIS

METABOLIC

ACIDOSIS

RESPIRATORY

ALKALOSIS

METABOLIC

ALKALOSIS

NORMAL RANGE OF PH 7.35-7.45

� PCO2 : PARTIAL PRESSURE OF CO2 IN THE BLOOD NORMAL VALUE

35-45mmHg or 4.1-5.6 K Pa � PO2 : PARTIAL PRESSURE OF OXYGEN IN THE BLOOD NORMAL

VALUE - 80-110mmHg or 10.5 – 14.5 KPa � STANDARD BICARBONATE : IS THE CONCENTRATION OF THE SERUM BICARBONATE

AFTER FULLY OXGENATED BLOOD HAS BEEN EQUILIBRATED WITH CO2 at 40mmHg at 380C

NORMAL LEVELS : 22-25mmol/Litre

ALKALOSIS

� METABOLIC ALKALOSIS : BASE EXCESS OR ACID DEFICIT 1. EXCESSIVE INGESTION OF ABSORBABLE ALKALI 2. LOSS OF ACID FROM STOMACH :VOMITING OR

ASPIRATION 3. CORTISONE EXCESS – CUSHING’S SYNDROME � COMPENSATION : A. RETENTION OF CO2 BY LUNGS B. EXCREATION OF BICARBONATE BASE BY THE

KIDNEYS(ALKALINE URINE)

CLINICAL FEATURES

� ALKALOSIS DUE TO LOSS OF ACID,MOST COMMON PYLORIC STENOSIS

� SEVERE ALKALOSIS : CHEYNE STOKES BREATHING WITH PERIODS OF APNOEA (5 TO 30seconds), TETANY.

� RENAL EPITHELIAL DAMAGE – RENAL INSUFFICIENCY.

� TREATMENT :CORRECT THE UNDERLYING CAUSE, ENCOURAGE HIGH URINARY OUTPUT.

� HYPOKALEMIC ALKALOSIS :VOMITING LEADS TO LOSS OF POTASSIUM & LOW SERUM K+ . K+ LEAVES THE CELL TO ENTER THE SERUM IN EXCHANGE FOR Na+ & H+ IONS WHICH CAUSE INTRACELLULAR ACIDOSIS.

� TREATMENT : CORRECT HYPOKALEMIA

IV FLUIDS + 40mmol/L OF KCL IF THE URINE OUTPUT IS ADEQUATE

MORE RAPID CORRECTION WITH ECG MONITERING

RESPIRATORY ALKALOSIS

� PCO2 IS BELOW 35 – 45 mmHg.

� EXCESSIVE PULMONARY VENTILATION.

� HYPER VENTILATION ON AN ANAESTHETIZED PATIENT, HIGH ALTITUDE, HYPER PYREXIA, HYPOTHALAMUS LESION, HYSTERIA.

� COMPENSATION : RENAL EXCREATION OF BICARBONATE.

� ANAESTHESIA ALKALOSIS :PALOR, FALL IN BP, RESPIRATORY ARREST.

� TREATMENT : INSUFFLATION OF CO2.

ACIDOSIS

�METABOLIC ACIDOSIS : EXCESS OF ACID OR DEFECIT OF BASE � INCREASE IN FIXED ACIDS : KETOACIDOSIS, DIABETES OR STARVATION, RENAL

INSUFFICIENCY. IN CARDIAC ARREST, INCREASED LACTIC AND PYRUVIC

ACIDS – ANAEROBIC TISSUE METABOLISM. ACUTE ACIDOSIS PH>7.1 � LOSS OF BASES : SUSTAINED DIARRHOEA, ULCERATIVE COLITIS,

GASTROCOLIC FISTULAE, HIGH INTENSTINAL FISTULAE.

� CLINICAL FEATURES : RAPID,DEEP,NOISY BREATHING. INCREASE IN PH STIMULATION OF

RESPIRATORY CENTRE HYPERPNOEA URINE IS STRONGLY AICIDIC � TREATMENT : 1) CORRECT TISSUE HYPOXIA AND TISSUE PERFUSION FIRST. 2) TREATMENT WITH BICARBONATE SOLUTIONS WILL CORRECT THE MEASURED ACIDOSIS BUT NOT THE PROBLEM ACUTE ACIDOSIS IN M.I. REQUIRES INFUSION OF 50mmol of 8.4% NaHCO3 SOLUTION.

RESPIRATORY ACIDOSIS

� PCO2 THE NORMAL RANGE. � IMPAIRED ALVEOLAR VENTILATION. � PULMONARY DISEASES LIKE CHRONIC BRONCHITIS, EMPHYSEMA ARE

EXAMPLES OF CHRONIC CAUSES � ACUTE CAUSES INCLUDE,CEREBRAL DISEASE,GUILLAINE – BARRE

SYNDROME,MYASTHENIA GRAVIS, CARDIOPULMONARY ARREST � CLINICAL FEATURES : CONFUSION, MYOCLONUS, PAPILLOEDEMA & WARM EXTREMETIES WITH

BOUNDING PULSE. � TREATMENT : TREAT THE UNDERLYING CAUSE. IMPROVE THE VENTILATION. � ACUTE RESPIRATORY ACIDOSIS :ENDO TRACHEAL INTUBATION

+MECHANICAL VENTILATION.

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