Fluids And Electrolytes

Celso M. Fidel, MD,FPCS,FPSGS Diplomate Philippine Board of Surgery FLUIDS AND ELECTROLYTES

INTRODUCTION  HOMEOSTASIS is determined by:  Individual’s Intake and output  Carefully and precisely regulated by the body during Health  One of the most critical aspects of patient’s care is management of the body composition of fluids and electrolytes

INTRODUCTION  Situations that impose a great impact on physiology of body fluid & electrolytes:  Diseases  Injuries  Operative Trauma  In disease states --- regulatory mechanisms often becomes impaired & IMBALANCES occur

INTRODUCTION  Thorough understanding of the mechanisms of fluids and electrolytes and certain metabolic responses is essential to the care of surgical patients  SURGEONS encounter these PROBLEMS:  Additional stress of SURGERY  Use of tubes that drain fluids  Patient’s inability to tolerate oral intake of fluids and nutrients

BODY WATER  Water constitutes between 50% to 70%TB Wt.  Average Normal Values Young Adult Male 60% of body wt. Young Adult Female 50% of body wt.  Total Body Water (% TBW) decreases steadily and significantly with age:  52% in males  47% in females

BODY WATER  Highest proportion of TB water :  Infants 75% to 80% of body weight  One Year Old averages 65% of BWt.  Lean individuals has greater proportion of water to TBW than the obese

FUNCTIONAL COMPARTMENT OF BODY FLUIDS  INTRACELLULAR  fluid w/in the body’s diverse cell population represent---- 40%  largest proportion ---- skeletal muscle  principal CATION----- K (potassium)‏  principal ANION ------ phosphates & proteins

FUNCTIONAL COMPARTMENT OF BODY FLUIDS  EXTRACELLULAR  Represents----- 20% of the BW  Two major subdivisions  plasma volume----- 5% of BW  Interstitial( extravascular ) 15% of BW

FUNCTIONAL COMPARTMENT OF BODY FLUIDS  EXTRACELLULAR  Non-functioning components----1%-2% B wt.  Connective tissue water  Cerebrospinal fluid  Joint fluids  The principal CATION----- Na+( Sodium)‏  The principal ANION------- Cl (Chloride and bicarbonates

FUNCTIONAL COMPARTMENT OF BODY FLUIDS  Gibbs-Donnan Equilibrium----- The product of concentration of any pair of diffusable cation and anion on one side of a semi-permeable membrane will equal the product of the same pair of ions on the other side

FUNCTIONAL COMPARTMENT OF BODY FLUIDS  TWO THIRDS RULE  Determination of the exact size of any one of the 3 compartments is virtually impossible  Total Body Compartment is approximately 2/3 of BODY Weight

FUNCTIONAL COMPARTMENT OF BODY FLUIDS  TWO THIRDS RULE  Of this 2/3; 2/3 is INTRACELLULAR & 1/3 is EXTRACELLULAR  Of the extracellular portion 2/3 is INTERSTITIAL & 1/3 intravascular

REPLACEMENT OF WATER  By Ingestion  By Metabolism-----combustion of foodstuff:  Each 100 calories of  FAT  CARBOHYDRATES  PROTEINS VITAL NEEDS W/C DEMANDS continuous water EXPENDITURE  Removal of Body Heat ----800cc ( SKIN AND LUNGS) 600-1000 >>>> RANGE DAILY RELEASES 14 CC OF WATER

 VITAL NEEDS W/C DEMANDS continuous water EXPENDITURE  Excretion of UREA, METABOLIC PRODUCTS & MINERAL SALTS  1200 mOsm of solute have to be excreted daily  A good kidney can CONCENTRATE urine up to 1400 mOsm solute

 VITAL NEEDS W/C DEMANDS continuous water EXPENDITURE  Average Adult excretes 900 cc H20/day  Normal H20 loss in Urine----800-1500cc/ day  Normal Na+ loss-----10-100 mEq/ liter of urine

Normal Daily Losses 1. GIT 100-200 ml loss in stools 2. GUT 1000- 1500 ml loss in urine 3. Insensible 600-800 ml in adults (divided equally between lungs and skin) a better term would be imperceptible loss

Abnormal Losses of Water 1. Fever - 10% increase insensible loss per degree above 37 C. 2. Tachypnea –doubling RR 50% increase resp. L 3. Evaporation- Sweating, ventilator, open wounds 4. GI –Fistula, Diarrhea, Tube drainage 5. Third space – Interstitium of lungs, bowel, soft tissues 6. Intraoperative losses

Tonicity  Body Fluids ---- composed of water and substances dissolved in it  Total number of particles in solution are constant throughout the body, although the nature of the individual solute varies in different parts of the body  Tonicity( property derived from the number of particles in solution) Normal----300 mOsm/L

Tonicity  In PLASMA 280 is due to ELECTROLYTES  1/2 --- 140 mOsm is coming from Na+  1/2 --- 140 mOsm from Chlorides & Bicarbonates  Crystalloids:  Sugar  Urea 10-20 mOsm  Creatinine  Protein ------ 2 mOsm

Electrolytes, What are They ?  Group of compounds-----DISSOCIATES in solution to form “IONS’ after the greek for “ GOING”  These ions each carry an electrical charge; example; NaCl -----dissolved in water provides Na+ ---- carries a positive charge Cl- -----carries a negative charge

Electrolytes, What are They ?  Those IONS carrying a (+) charge migrated to FARADAY’s (-) electrode or “CATHODE” were called ”Cations” after the Greek for “DOWN”  Those IONS carrying a (-) charge migrated to FARADAY’s (+) electrode or “ANODE” were called ”anions” after the Greek for “UP”

Electrolytes, What are They ?  Cations in the body; Na+, K+, Ca++, Mg++  Anions in the body include ; Cl-, HCO3-, HPO4=, SO4=; ions of inorganic acids such as:  Lactate  Pyruvate  Aceto-Acetate  Proteinates

Electrolytes, What are They ?  Each of the water compartments of the body contains electrolytes. However the composition and concentration of these electrolytes in the water of each compartment differ from that of the others.

Electrolytes, What are They ?  Physiologic and Chemical Activity of electrolytes are proportional to:  Number of particles present per unit volume ( MOLES or MILLIMOLES)‏  No. of electrical charges per unit volume ( Equivalents or Milliequivalents per liter)‏

Electrolytes, What are They ?  mEq/L=mgs./L X val. divided by the atomic Wt. = mgs/ 1000cc X Valence Atomic Weight  OSMOLARITY >>>expression of concentration of ions and proteins in solution in body water.  Water moves freely in the body to prevent the development of any compartmentalized osmolar concentration difference.

Electrolytes, What are They ?  Electrolyte Concentration in Serum Na+ -------- 135-145 mEq/ liter K+ -------- 3.5-5.5 mEq/liter Cl- ----- 85-115 mEq/liter HCO3- ---- 22-29 mEq/liter Mg++ ---- 1.5-2.5 mEq/liter Ca++ ---- 4-5.5 mEq/liter

ELECTROLYTE COMPOSITION OF BODY FLUIDS Na+ K+ H+ Cl- HCO3 Proteins PO4 SO4- Plasma 142 4.5 100 25 16 2 1 Gastric Low Acid 45 30 70 120 25 High Acid 100 45 0.015 115 30 Intestinal Juice 120 20 30 Bile 140 5 40 Pancreatic Juice 130 15 80 Intracellular 10 150 5 10 60 100 20

NORMAL DAILY FLUID& ELECTROLYTE LOSSES AND REQUIREMENTS  LOSSES/ 24 hours  Substances Urine Skin Lungs Feces Total  WATER 1200-1500 200-400 500-700 100-200 2300-2600  SODIUM 100 mEq 40 mEq/liter 80-100 mEq  POTASSIUM 100 mEq 80-100mEq  CHLORIDES 150 mEq 40 mEq/ liter 100-150 mEq  REQUIREMENTS  WATER 35 ml/ kg. body weight PEDIATRICS 100 ml/kg first 10 kg. body weight 50 ml/kg next 10 kg. “ “ 20 ml/kg for each additional body weight  SODIUM 1 mEq/kg body weight  POTASSIUM “ “ “ “  CHLORIDE 1.5 mEq/ kg. body weight  HCO3 0.5 “ “ “ “

THE IONS  SODIUM  Principal Cation of extracellular fluid  Normal requirement is met by the average diet  Average intake----- 100 mgs daily  Sweat conc. -----27mEq/ L is to 100mEq /L  Total secretion---Alimentary Tract 1000-1200 mEq  ADH of Pituitary promotes Na+ excretion from the kidney to some extent & to markedly favor water resorption from the distal tubules.

THE IONS  POTASSIUM (cation)‏  Major exchangeable portion lies within the cell  Daily turnover of K+ requirement represents 1.5 to 5% of the total K+ content of the body.  Normal 70 kg. man----- 3,200 mEq  Average woman--------- 2,300mEq  Normal requirement met by average diet  Gastric Juice Content----15-40mEq/liter  Healthy cell maintains high K+ & low Na+ conc.  Patient under stress of disease or in the postop. period>> Normal Kidney excretes 80-90 mEq/day

THE IONS  POTASSIUM (cation)‏  At 7 mEq/L in Serum----- elevation of T waves on Electro Cardio Gram  At 8-10 mEq/L ------Arrhythmia & Heart Block  CHLORIDE (ANION)‏  Na+ to Cl- ratio is 3:2 in serum & extracellular compartment  It follows changes in Na+ concentration EXCEPT in GASTRIC OBSTRUCTION;  Chloride is low  Na+ is normal  Alkalosis is severe

DIAGNOSIS OF IMBALANCES  It is the center of any scheme of FLUID and ELECTROLYTE Balance  Nature of imbalances and approximate magnitude are based on:  History  Clinical Signs and Symptoms  Certain Laboratory Studies  Past Clinical Experience

DIAGNOSIS OF IMBALANCES  CLUES FROM THE HISTORY  In Gastric Outlet Obstruction present in  Duodenal Ulcer will produce  Pyloric Stenosis alkalosis (loss of Chloride & K+; Hypokalemia; loss of H20 & Na+)‏  Vomiting secondary to a cause other than gastric Outlet Obstruction:  Loss of H2O If there is a shift in ACID  Loss of Na+ BASE balance, it is towards  Loss of K+ METABOLIC ACIDOSIS vomiting

DIAGNOSIS OF IMBALANCES  CLUES FROM THE HISTORY  Diarrhea secondary to:  Cholera Loss of  Ulcerative Colitis H20, K+, ACIDOSIS  Ileostomy dysfunction Na+  Burns produces acute loss of PLASMA & Extra- cellular fluid (Water, Proteins, and Na+)‏  Sweating if excessive causes appreciable loss of both Na+ & H20------ Shrinkage of Extracellular Fluid Volume -------VASCULAR COLLAPSE

DIAGNOSIS OF IMBALANCES  P.E. should give attention to:  BODY WEIGHT  Weight gain >>>H20 retention  Weight loss 300-500 gms./day expected in postoperative Patients.>>>> In excess of 300- 500 gms/ day indicates H20 loss.  Tissue Turgor >>Decrease in T T in volume of the Interstitial Fluid compartment of ECF ( Na+ dependent)‏  Skin Turgor>> useful indicator of diminished interstitial fluid volume

DIAGNOSIS OF IMBALANCES  P.E. should give attention to:  Tissue turgor  Tongue>> most reliable indicator forT.T  Normally it has a single “Median Furrow”  Additional furrows parallel to the median furrow appears with decrease interstitial volume and a need for Na+  Moisture of the axilla and groin . Dry but other- wise normal axilla----H20 deficit, at least 150cc  Jugular Veins ------Normally it fills to the anterior border of the sternocleidomastoid muscle when the patient is supine.

DIAGNOSIS OF IMBALANCES  P.E. should give attention to:  Blood Pressure and Pulse  Tachypnea>> earliest sign of decrease BVolume  Postural Hypotension Need for Blood & Na  Hypotension when Supine containing fluid  Edema and Rales  Pitting Edema>>> Na+ increase >> 400 mEq  Rales>> Acute increase in Volume by at least 1500cc

DIAGNOSIS OF IMBALANCES  LABORATORY TESTS & Other PARAMETERS  Hematocrit  Urine Specific Gravity  Na+ levels in serum and urine  CVP monitoring  Pulmonary Wedge Pressure

DIAGNOSIS OF IMBALANCES  LABORATORY TESTS & Other PARAMETERS  Hematocrit  Urine Specific Gravity  Na+ levels in serum and urine  CVP monitoring  Pulmonary Wedge Pressure  Determining the Amount of the Deficit  A Vol(H2O) deficit---- Estimate from patient’s Body Wt.& appearance or from the serum Sodium level. The hematocrit gives also useful information.

DIAGNOSIS OF IMBALANCES  CLINICAL ESTIMATES  MILD Dehydration----- Patient losses 3% of the Body Weight ----- THIRSTY  MODERATE Dehydration ------ Patient losses 6% of the Body Wt. Clinical signs of dehydration are Evident:  Marked Thirst and Dry Mouth  No groin and axillary Sweat  Loss of Skin Turgor .

DIAGNOSIS OF IMBALANCES  CLINICAL ESTIMATES  SEVERE Dehydration------Patient losses 10% of Body Weight:  Clinical signs of Dehydration are marked.  Hypotension may be present  Patient may be confused & delirious.  BODY WATER CALCULATIONS  Body H20 = Normal Serum Na+ X normal B H20 Measured Na+ value

DIAGNOSIS OF IMBALANCES  Electrolyte deficits. They are calculated after the lab results for Na+. K, Cl, and NaHC03 are in.  NaCl & HCO3 deficit are calculated using foll: DEFICIT= NORMAL VOLUME –OBSERVED BODY VOLUME x ELECTROLYTE DISTRIBUTION IN BODY COMP% x BODY WT(KG) WHERE: NA DISTRIBUTION = 60 % CL “ 20 % HCO3 “ 5O%

DIAGNOSIS OF IMBALANCES  Electrolyte deficits.  The K+ deficit is figured differently w/normal Blood pH:  For every 1.0 mEq/L decrease in concentration at or above 3.0 mEq----consider the total body deficit as 100-200 mEq.  For every1.0 mEq/L decrease in the K+ conc. below 3.0 mEq/L -----consider the total body deficit as another 300-400 mEq.

DIAGNOSIS OF IMBALANCES  ABNORMAL PATTERNS in Fluids & Electrolytes  Disorders of composition & concentration  Disorders of Volume  Disorders of Acid-Base Balance CLINICAL STATES  HYPONATREMIA  HYPERCLOREMIA  HYPERNATREMIA  ACID BASE BALANCE  ISOTONIC DEHYDRATION  HYPOKALEMIA  HYPERKALEMIA

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  Pathophysiology  Hypovolemic or Isovolemic  Mechanism:  Loss of Na+ containing fluid and replacement with salt free fluid( isovolemic)‏  Salt free fluid and administration in excess in the absence of salt loss ( dilutional Hyponatremia)‏

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  Causes  Loss of fluid with high Na+ content:  Fistula  Ngt Drainage  Vomiting  Diarrhea  Excessive URINE Na+ wastage  Diuretics  Chronic Nephritis  Adrenal Cortical Insufficiency as in Addison’s disease  Over infusion of salt free fluid ( dilutional Hyponatremia)‏

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  Causes cont’d  Loss of Extracellular Fluid:  Externally:  Burns  Marked Sweating  Internally as in Third Space loss:  Peritonitis  Ascites  Ileus  Pancreatitis

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  Clinical Presentation  Accumulation of intracellular fluid could cause CNS symptoms:  Serum Na+ below 130 mEq/Liter ( Mild)‏  “ “ “ 113 “ “ (Severe)‏  CNS depression, Confusion, Somnolence  Signs of Increase Intracranial pressure  OLIGURIC Renal Failure in Severe Hyponatremia

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  Management  Repeated Na+ determination; other Electrolytes  H20 deprivation, Use diuretics  Administer Na+ containing Fluids  Sodium must be Titrated slowly back to Normal

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  “ Sample CASE” A muscular 50 year old man with polycystic kidney disease presents w/ hypotension, confusion, oliguria, and no axillary sweat. Past medical record reveals that he has polyuria has been eating a low salt diet because of mild hypertension. BUN has been stable at 40mgs/dL;Blood CO2 is 15mmol/L (Metabolic Acidosis) and Na+ level of 120mEq/L.Body Weight is 90kgs; Urine output- 170ml/day GIVEN: Na+ deficit =140mEq – 120mEq = 20mEq/L Total Body H20 = 90kgs X 60 = 54 L Fluid Loss = 10% (Clinical Findings)‏ First Step: COMPUTE for Hypotonic Na+ deficit Hypotonic Na+ deficit = Na+ deficit X TBW = 20mEq X 54 L =1080(Hypotonic Na+ def.)‏

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  “ Sample CASE” 2 nd Step : COMPUTE for the isotonic Na+ deficit Find out the Isotonic Fluid loss or How much fluid is necessary to revert to ISOTONIC STATE . Formula ISOTONIC FLUID LOSS =Weight X % of FLUID LOSS 90 Kgs. X 10% (9 Liters)‏ Then compute for isotonic Na+ deficit Formula: Isotonic Na+ Loss X NORMAL Na+ level 9 Liters X 140mEq = 1260mEq Total Na+ REQUIREMENT: Hypotonic Na+ Deficit + Isotonic Na+ deficit + Daily requirement 1080mEq + 1260mEq + 75mEq = 2415mEq Initially only ½ is given so divide it by 2 =1207.5 mEq

DIAGNOSIS OF IMBALANCES  HYPONATREMIA  “ Sample CASE” 3 rd Step: COMPUTE for the 24 hours H20 requirement The daily H20 requirement in an OLIGURIC patient is reduced: FORMULA 0.2 ml/kg body wt. + preceeding 24 hour Urine Output +10% for every rise of 1 degree in body temp. =(0.2ml X 90 X 24) + 170 =602 ml/day 24 HOUR H20 requirement = Isotonic Fluid loss(9 L) + 600 = 4.8 Liters 2 4 th Step: Compute for Bicarbonate. The ideal replacement solution should contain a NaCl ratio of 1.4:1 particularly if the patient is ACIDOTIC.

DIAGNOSIS OF IMBALANCES  HYP0NATREMIA  “ Sample CASE” 4 th Step: Compute for Bicarbonate. The ideal replacement solution should contain a NaCl ratio of 1.4:1 particularly if the patient is ACIDOTIC. Sub- Step: Compute for Chloride Requirement 1.4 = 1245 X= 1245 =890 mEq as NaCl 1 X(mEq) 1.4  The Bicarbonate requirement is thus: 1245- 890 =355 mEq of HCO3  PATIENT’S FLUID & ELECTROLYTE REQUIREMENT  4.8 liters of 5% Dextrose in 0.9 % NaCl Add 8 vials of Na2CO3 (44 mEq/50 cc)‏ Plus 200 cc of 5% NaCl injection

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  Pathophysiology ECF Hyperosmolarity= shift of H20 from cell----  --  ECF-  More Fluid ---  DEHYDRATION Increased Intracellular Osmolality --  CNS effects:  Fever  Hallucination  Delirium

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  Causes  Prolonged Fever  Large surface Burns --  3-5 Liters loss/day  Tachypnea – Do Tube Tracheostomy  Renal Damage  Loss of Solute  Urine High Output Failure  Desert Exposure  Drinking Salt H2O

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  Management  Gradual Reduction of Serum Na+  Rehydrate patient with salt Free H20  Formula: 70 kg patient with Na+ of 160mEq Total Body Water 60% X 70kgs = 42 Liters= Current Body Water 140 =0.87 or 0.9 16 0.9 X 42 =37.8 Liters current Body Water 42L- 37.8= 4.2 Liters ( water Needed)‏

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  “ Sample CASE” A moderately lean woman with esophageal stricture has a serum Na+ level of 160mEq /L (normal is 140mEq). Her present weight is 70kgs.  HER REQUIREMENTS WOULD BE CALCULATED AS FOLLOWS:  Current Body Water 140mEq =7/8 =87.5 % of normal 160mEq  WATER Loss>>> 100%- 87.5% =12.5% of water  PATIENT’S NORMAL total BODY WATER 70 X 60% = 42 Liters  H20 DEFICIT 42 L X 12.5% = 5.3 Liters

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  “ Sample CASE ” A moderately lean woman with esophageal stricture has a serum Na+ level of 160mEq /L (normal is 140mEq). Her present weight is 70kgs.  HER Fluid REQUIREMENT 2.7 + 2.4 = 5.1 L of fluid needed in the next 24 hours containing 70mEq of Na+ FORMULA USED: ½ H20 Deficit + normal daily fluid requirement ½ H2O Deficit + ( 35cc X70 kgs.) 2.4 Liters

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  Example If the same patient has diarrhea as well as esophageal stricture and has persisted with weakness, confusion; hypotension  CALCULATIONS WOULD BE AS FOLLOWS  Present Body Water 140 =7/8 = 87% of NORMAL 160  Water Loss 100-87.5 =12.5%  Patient’s Normal Body Water =70kgs X 60% = 42 Liters  H20 Deficit: 42 L X 12.5% =5.3 Liters  CLINICAL Findings shows 10% dehydration CALCULATIONS should be changed

DIAGNOSIS OF IMBALANCES  HYPERNATREMIA  Example If the same patient has diarrhea as well as esophageal stricture and has persisted with weakness, confusion; hypotension  CLINICAL Findings shows 10% dehydration CALCULATIONS should be changed  FLUID LOSS 10% of 70kgs = 7 liters  ISOTONIC Fluid loss = 7 – 5.3 =1.7 Liters  Na+ loss in Isotonic Fluid = 1.7 L X 140mEq = 238mEq  24 Hour Fluid Requirement= ½ H20 deficit + Normal Body Fluid = ½ of 7( 7/2) +2.4 = 5.9 L  24 Hour Na+ Requirement = ½ Na+ deficit + 70 =189mEq  This can be given as: 4 liters of 5% Dextrose in Water plus 1200 cc of NORMAL Saline Solution

DIAGNOSIS OF IMBALANCES  ISOTONIC DEHYDRATION  The Serum Na+ Concentration is Normal  “ EXAMPLE” A short obese alcoholic patient presents with  Vomiting due to gastritis  102 F fever due to pneumonitis  Complaining of thirst  Has dry mouth  No groin or Axillary Sweat  Alert and Normotensive  Weight of 100kgs.  Serum Na+ is 140mEq/L  Serum K+ 3mEq/L

DIAGNOSIS OF IMBALANCES  ISOTONIC DEHYDRATION  FLUID and ELECTROLYTE Requirement  Fluid Loss = 6% (based on Clinical Findings)‏  Isotonic Fluid loss 100kgs X 6% = 6 Liters  Na+ loss (in isotonic fluid) 140mEq X 6=840mEq  24 hours Na+ Requirement 840 + 100mEq = 520mEq 2  24 hour Fluid Requirement 6 + 4.9 L =7.9 L 2

DIAGNOSIS OF IMBALANCES  ISOTONIC DEHYDRATION  FLUID and ELECTROLYTE Requirement  EXPLANATIONS:  The daily requirement is 4.9 instead of 3.5 because of the patient’s fever. Each 1 degree rise in temperature increase by at least 10%  Fluid and Na+ replacement can be given as:  3 Liters of 5% dextrose in Normal Saline  2 Liters of 5% dextrose in water  200cc of Normal saline  KCl should be added as indicated at ½ of the DEFICIT plus the the daily requirement (100mEq) provided urine flow is adequate.  KCl should be divided among the solutions

DIAGNOSIS OF IMBALANCES  HYPOKALEMIA  CAUSES.  Chronic Pyloric Obstruction  Ulcerative Colitis  Prolonged Vomiting  Fistula  Diarrhea  Diuretic Therapy  Nephritis  Adrenal Hyperactivity( Stress; Cushing’s Syndrome)‏  PATHOPHYSIOLOGY  Loss of GASTRIC JUICE --  minimal loss of K+ --  Loss of Cl.---  insufficient Cl. For renal Tubular reabsorption of Na+ Loss of Na+ ions>>>Adrenal and Renal mechanisms will conserve Na+>>>and add in exchange K+ and H+ are excreted>>>>>>HYPOKALEMIA

DIAGNOSIS OF IMBALANCES  HYPOKALEMIA  CLINICAL FEATURES  Less than 3.5mEq/L in serum  Associated with:  Diuretics  Metabolic Alkalosis  Aldosterone Secretion  GIT losses

DIAGNOSIS OF IMBALANCES  HYPOKALEMIA  CLINICAL FEATURES  Prolonged Ileus, Hyporeflexia, Paralysis  Increased sensitivity to digitalis  Favors ALKALOSIS (because of Acid loss) and alkalosis DECREASE K+  ECG shows Prolonged QT; Depressed ST; T Wave inversion  Early Signs of K+ Depletion:  Malaise and Weakness  Paralytic Ileus and Distention  Muscular Paresis

DIAGNOSIS OF IMBALANCES  HYPOKALEMIA MANAGEMENT  Add KCl to IV Solution but not to exceed 20mEq/hour  Usual Daily Requirement is 40mEq/day  CONTRAINDICATIONS TO K+ THERAPY  UNTREATED Adrenal Insufficiency  UNTREATED Renal Failure  TEMPORARY Renal Shutdown

DIAGNOSIS OF IMBALANCES  HYPERKALEMIA CLINICAL FEATURES  Serum K+ 6mEq/L or over

DIAGNOSIS OF IMBALANCES  HYPERKALEMIA CLINICAL FEATURES  Seen in:  Renal Failure  Massive injury like Burns  Acidosis and Low Flow States  Massive GI Hemorrhage  Administration of K+

DIAGNOSIS OF IMBALANCES  HYPERKALEMIA CLINICAL FEATURES  Manifested as : 1. Nausea 2. Vomiting 3. Diarrhea 4. Heart BLOCK 5. Loss of Digitalis Effect 6. CARDIAC ARREST

DIAGNOSIS OF IMBALANCES  HYPERKALEMIA PATHOPHYSIOLOGY  In Renal Failure K+ cannot be Excreted, there will be >>accumulation in PLASMA.  In Renal Failure >>>>The Failure to excrete H+ will shift H+ into Cell to maintain pH>>>>K+ will leave cell>>>PLASMA Hyperkalemia.  ECG will show peaked T Waves ,Wide QRS

DIAGNOSIS OF IMBALANCES  HYPERKALEMIA MANAGEMENT The principle is to shift back K+ into the cell. 1. Na2C03 given to combat Acidosis>>K+ ion to back into the cell in exchange of H+ 2. IV glucose with insulin>> K+ taken up into the cell w/ each molecule of glucose that enters the cell. 3. Dialysis 4. Exchange Resin 5. Diminished uptake of K+

DIAGNOSIS OF IMBALANCES  HYPOCHLOREMIA CLINICAL FEATURES  Sodium Chloride is below 85mEq/Liter  Seen in Upper GI Obstruction w/ vomiting. One may loss as much as 120-130mEq/day  Hypochloremia in itself does not produce striking Clinical Changes.

DIAGNOSIS OF IMBALANCES  HYPOCHLOREMIA PATHOPHYSIOLOGY  Diuretics >> cause increase loss of Chloride thru Kidney>> Urinary Concentration of Chlorides higher than Sodium Concentration.  MANAGEMENT  Treat with KCl solution  May use NH4Cl or 0.1 N HCl (ideal for hypochloremia due to metabolic Alkalosis )‏

DIAGNOSIS OF IMBALANCES  HYPERCHLOREMIA CLINICAL FEATURES  Chloride above 105mEq/L  Seen in Hypernatremia  Seen in Uretero Intestinal Anastomosis  Seen in Obstructive Uropathy  Excessive intake of NH4Cl

DIAGNOSIS OF IMBALANCES  HYPERCHLOREMIA PATHOPHYSIOLOGY  Uretero Intestinal Anastomosis>>>Reabsorption by bowel>>>Accumulation of Cl in excess of Na+ ion ( potentiated by Renal Insufficiency)‏  Associated w/ Metabolic Acidosis  MANAGEMENT  Correct Associated Abnormalities  Remove Salt ( Ammonium)‏  Allow Kidneys to Compensate

PRINCIPLES OF ACID BASE BALANCE  Normal H+ ion concentration in Extracellular fluid is maintained at pH 7.36-7.42  Daily Metabolic products are H+ and CO2  To keep the pH constant, Acids are neutralized by two mechanisms:  Buffer System of Body Fluids  Regulatory functions of the LUNGS & KIDNEY  Most important Buffer System is the Bicarbonate Carbonic Acid System H2CO3 HCO3 + H+

PRINCIPLES OF ACID BASE BALANCE pH is determined by ratio of base bicarbonate to carbonic Acid: HCO3 pH = Pk LOG H2CO3 ( HENDERSON HASSELBACH’S EQUATION)‏  Carbonic Acid (H2CO3) is a function of the dissolved CO2. This is determined by the pCO2 of Blood & is regulated rapidly and accurately by the LUNGS Bicarbonate(HCO3) of blood is controlled by the rate of its renal secretion .

PRINCIPLES OF ACID BASE BALANCE  At pH 7.4 ratio of Carbonate to Carbonic Acid is 20:1  In METABOLIC ACID BASE Shifts, effects on buffer system is on LEVEL of BICARBONATE INCREASED: Increased Bicarbonate = ALKALOSIS Decreased “ = ACIDOSIS

PRINCIPLES OF ACID BASE BALANCE  In METABOLIC ACID BASE shifts = LUNGS compensates:  Metabolic Acidosis>> Increased Ventilation >> more CO2 released less H2CO3  Metabolic Alkalosis>> Decreased Ventilation > more CO2 retained >> Increased H2CO3  IN RESPIRATORY ACID BASE shifts the effect on the buffer system is a GAIN or LOSS of CARBONIC ACID  Compensatory Mechanism is via the KIDNEYS by retaining or Excreting BICARBONATES

PRINCIPLES OF ACID BASE BALANCE  Respiratory Acidosis = Increased H2CO3 Compensated by RENAL RETENTION OF BICARBONATE  Respiratory Alkalosis = Decreased H2CO3 is Compensated by RENAL EXCRETION of BICARBONATE  Serum HCO3 20 pH = Kidney Serum H2CO3 1 Lungs

PRINCIPLES OF ACID BASE BALANCE   To Follow Acid Base Changes KNOW:  Signs and Symptoms  Pathophysiology  Plasma pH  Arterial pCO2  Total Extractable CO2 measured as venous CO2 content corrected to pCO2 of 40mm Hg

PRINCIPLES OF ACID BASE BALANCE   METABOLIC ACIDOSIS  Clinical Aspects  Excess H+ in plasma>>Fall in pH >>Diminished>> Plasma Bicarbonates seen in:  Loss of fluid rich in Na2CO3  Adrenal Insufficiency>> Renal loss of Na2C03  Low flow state >>>Lactic Acid  Diabetes Mellitus

PRINCIPLES OF ACID BASE BALANCE   METABOLIC ACIDOSIS  Pathophysiology  Increased rate & depth of breathing> Decrease plasma pC02>>>Decrease H2CO3 with return of pH to normal  Laboratory Findings  pH below 7.38  HCO3 less than 24mEq/minute  Arterial pCO2 40mmHg  Acidic Urine w/ low Na+ content

PRINCIPLES OF ACID BASE BALANCE   METABOLIC ACIDOSIS  Management  Treat Cause  Adjustment to respirator (if patient is attached to one). Increased RATE decrease arterial pCO2.  METABOLIC ALKALOSIS  Clinical Aspects  HCl loss due to vomiting, gastric drainage  Loss of K+ and Cl- in urine

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Clinical Aspects cont’d  Diuretics  Adrenal Steroids  Administration of Na2CO3 or Sodium Citrate (in blood transfusion)‏  Pathophysiology  Due to uncompensated loss of Acids or retention of Bases

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Pathophysiology  In Metabolic Alkalosis Increase urinary K+ loss>>H+ and Na+ ion enter the cell>> Decrease of Extracellular H+ ion concentration>> further >>increase in Alkalosis.

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Pathophysiology  LUNG Compensation: Hypoventilation>>> CO2 accumulation>> Increased Carbonic Acid.

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Pathophysiology RENAL Compensation: Increased Excretion of Bicarbonat e in ALKALINE Urine

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Condition is usually seen in:  Multiple Transfusion  Hyperventilation  Volume Reduction  Increased Aldosterone Secretion  Administration of Large volume of Ringer’s Lactate

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Laboratory Findings: 1. Blood pH Higher than 7.44 2. HCO3= Higher than 28mEq/L 3. Arterial PCO2= 40 in the presence of Respiratory Compensation

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Management  Replace lost Na+, Cl, and K+ ions  Lower pH by using of 0.1 N HCl  In moderately severe Alkalosis where there is Increased Renal K+ excretion, permit the tubule to retain H+ (treat) w/ IV KCl  Severe METABOLIC ALKALOSIS is the only good indication for the administration of NH4CL

PRINCIPLES OF ACID BASE BALANCE  METABOLIC ALKALOSIS  Severe METABOLIC ALKALOSIS is the only good indication for the administration of NH4CL

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ACIDOSIS  Clinical Aspects  It is caused by Pulmonary Insufficiency 1. Failure to excrete CO2 via the Lungs with normal efficiency as in: a. Pneumonia b. Emphysema c. Fibrosis

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ACIDOSIS  Clinical Aspects  It is caused by Pulmonary Insufficiency 2. Hypoventilation caused by a. Pulmonary Edema b. Injury c. Post op. Atelectasis d. Drugs e. Poor Ventilation( Respirator)‏

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ACIDOSIS  Clinical Aspects  Manifested by: 1. Somnolence 2. Confusion 3. Coma due to CO2 Narcosis

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ACIDOSIS  Pathophysiology  Compensatory Mechanism: 1. Increase Tubular reabsorption of Na+ and bicarbonate by Kidneys 2. Increase excretion of H+ ions

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ACIDOSIS  Laboratory Findings 1. Blood pH below 7.38 2. Arterial pCO2 over 50mm Hg 3. Acute Respiratory Acidosis= Plasma H2CO3 not increased 4. In Chronic state it’s elevated to 20mEq/L

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ACIDOSIS  Management  Control ventilation to increase inspired 02>>> Return of Arterial Blood Gas to Normal  Careful and slow correction of pH and pCO2 so as not to produce rapid changes with associated Cardiac instability

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ALKALOSIS  Clinical Features  Due to Hyperventilation seen in: 1. Pulmonary Infection 2. Hysteria 3. CNS Injury 4. Occasionally during Anesthesia 5. Fever 6. Pain 7. Apprehension 8. Salicylate Poisoning

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ALKALOSIS Pathophysiology  Hyperventilation leads to Decrease in Alveolar CO2 concentration>>> Decrease in serum H2CO3  Compensatory Mechanism: RENAL increase tubular excretion of Na2CO3

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ALKALOSIS  Laboratory Findings : 1. Blood pH more than 7.46 2. Arterial pCO2 is lower than 36mm Hg. 3. With renal compensation Bicarbonate level will fall 4. Urinary Na+ concentration is high

PRINCIPLES OF ACID BASE BALANCE  RESPIRATORY ALKALOSIS  Management  Directed at its initiating Causes  Note:  Mild respiratory alkalosis is common postoperative problem  Associated muscle irritability or frank tetany especially if serum calcium++ level is low  Corrected by administration of calcium salts Calcium Chloride, Calcium Gluconate

PRINCIPLES OF ACID BASE BALANCE  FORMULA FOR Acid Base Imbalance Serum HCO3 = 20 Serum H2CO3 1  in the numerator 20/1 to 10/1 >Met. ACIDOSIS  in the numerator 20/1 to 30/1 >Met. ALKALOSIS  in the denominator 20/1 to 20/2>>Resp Acidosis  in the denominator 20/1 to 20/.5 > R. Alkalosis

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  PRIORITIES 1. Correct SHOCK and restore Blood Volume>>Normal 2. Restore Colloid Osmotic Pressure 3. Correct Acid Base Imbalance 4. Restore Blood Osmolality 5. Correct K+ deficit 6. Correct Total Body Electrolytes disturbance (static debt) and establish daily maintenance

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  DEFICIT CORRECTION  Fluid and Electrolyte Therapy to Correct existing Deficit. Examples :  Blood volume deficit in Acute or Chronic Blood loss.  Extracellular or Intracellular deficit in dehydration  Deficit correction is added to maintenance and replacement therapy in order to restore H20, salt balance  Deficit correction is also Top priority in Fluid and Electrolyte therapy

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY Necessary to Replace Abnormal (continuing) losses from or within the body. Example via drainage tubes.

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY  Gastrointestinal Losses  If these are purely gastric( succus gastricus); A solution providing 0.45% NaCl mEq plus 40 mEq of KCl per liter is used for replacement.

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY  Gastrointestinal Losses  If the fluid lost contains intestinal (succus entericus) Lactated Ringer’s solution plus 10 mEq KCl per liter is used .

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY  Third Space Loss 1. The amount of loss varies with the magnitude of injury. 2. Lactated Ringer’s solution plus Albumin is used.

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY  Continuing losses require volume for volume replacement and added to maintenance requirements.  Replacement Therapy has second priority in Fluids & Electrolyte Therapy

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  MAINTENANCE THERAPY  Clinical Example: Average size 60kgs woman has an Elective Cholecystectomy. No drainage tubes.  Patient’s Normal Daily Requirements  H2O : 35ml/kgs X 60 >>> 2100 cc  Na+ : 1mEq/kgs X 60 >>> 60mEq  K+ : 1mEq/kgs X 60 >>> 60mEq  Cl- : 1.5mEq/mEq X 60 >>> 90mEq  HCO3-: 0.5mEq/mEq X 60 >>> 30mEq

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  MAINTENANCE THERAPY Methods to calculate H20 maintenance requirement 1. Utilization of body water as a guide for H20 Ex. 70 kg. x 0.5 x 24 hrs + 500ml/24 hrs = 1340ml/24hrs 2. It can be based on patient’s weight (Pediatric Patients)‏ 100 ml/kg for the first 10 kg of body weight 50 ml/kg for the next 10 kg of body weight 20 ml/kg for each additional kg of body weight

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  MAINTENANCE THERAPY Methods to calculate H20 maintenance requirement 3. A given amount of water /kg body wt. can be used. (35 ml/kg/24 hours)‏ 4. A given amount of fluid regardless of wt. (125ml/hr)‏

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  MAINTENANCE THERAPY  IV Fluids would be as follows: 1. 1000 ml of 5% Dextrose in H2O + 40mEq Kcl 2. 650 ml of 5% Dextrose in H20 + 20mEq KCl 3. 450 ml of 5% Dextrose in Lactated Ringer’s solution

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  MAINTENANCE THERAPY  This would provide:  2100 ml of Water  58.5mEq of Na+( 4.5 X 1.3mEq/dl LR  61.8mEq of K+ (60mEq from KCl+1.8mEq  109mEq of Cl( 60mEq from KCl + 49mEq  12.6mEq of HCO3( 4.5 X 2.8mEq/dl LR

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY  The same patient develops ileus. NGT was placed. Over 24 hours 1600 ml NGT bile stained fluid was collected. Normal serum electrolytes.  For replacement she would require: 1600 ml D5LR solution +10mEq of KCl

PRINCIPLES OF MANAGING FLUID, ELECTROLYTE AND ACID BASE IMBALANCE  REPLACEMENT THERAPY Her maintenance requirement would be the same  1000 ml of 5% Dextrose in H2O + 30mEq Kcl  1000 ml of 5% Dextrose in H20 + 30mEq KCl  2 liters of 5% Dextrose in Lactated Ringer’s solution + 10mEq KCl to each liter.  Run at 170ml/hr( 400 maintenance 600 Replacement)‏

OTHER COMMONLY USED FLUIDS SOLUTIONS NA+ CONTENT Cl CONTENT USES 3% NaCl INJ. 51 51 For symptomatic Na deficit 5% NACl INJ 85 85 SAME AS ABOVE 14.9% KCl INJ 20 cc ampule 40 40 Additive for K+ Correction & maintenance 7.5% NA2CO3 44.6 44.6 HCO3 Additive for GI Losses; Correct Metabolic Acidosis

COMMONLY USED PARENTERAL SOLUTIONS SOLNS. Na+ K+ Cl- HCO3- Ca++ Principal Uses 0.9 NaCl 154 154 Correction of Hyponatremia ECF Replacement 0.45NaCl 77 77 Na+ Maintenance; Gastric Fluid Replacement Lactated Ringer’s Solution 130 4 109 28 9 Best ECF Replacement; Correction of Isoosmolar Deficit 5% Dextrose In Water Correction of insensible water loss; Maintenance and Correction of Hyperosmolar Dehydration

Fluids And Electrolytes

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Fluids And Electrolytes