FLUIDS, ELECTROLYTES, WATER AND ACID – BASE BALANCE

1. FLUIDS, ELECTROLYTES, WATER AND ACID – BASE BALANCE NRS 105 Collings 2011

2. DISTRIBUTION OF BODY FLUIDS INTRACELLULAR INSIDE THE CELL EXTRACELLULAR OUTSIDE THE CELL INTRAVASCULAR INSIDE THE VESSELS (ARTERIES AND VEINS) INTERSTITIAL NOT IN THE CELL, NOT IN THE VESSELS BETWEEN THE CELL (contains LYMPH) TRANSCELLULAR CSF, PLEURAL FLUID, INTRAOCCULAR, GI, PERITONEAL, SYNOVIAL NRS 105 Collings 2011

3. BODY FLUID COMPARTMENTS NRS 105 Collings 2011

4. ELECTROLYTES IN BODY FLUIDS NORMAL VALUES SODIUM (Na+) 135–145 mEq/L POTASSIUM (K+) 3.5 – 5.0 mEq/L IONIZED CALCIUM (Ca++) 4.5 – 5.5mg/dl BICARBONATE (HCO3) 22 – 26 mEq/L CHLORIDE (Cl--) 95 – 105mEq/L MAGNESIUM (Mg++) 1.5 – 2.5mEq/L PHOSPHATE (PO4---) 2.8 – 4.5mg/dl NRS 105 Collings 2011

5. MEASUREMENTS OF ELECTROLYTES mEq/L MILLIEQUIVALENTS PER LITER THE NUMBER OF GRAMS OF A GIVEN ELECTROLYTE DISSOLVED IN A LITER OF PLASMA NRS 105 Collings 2011

6. VOCABULARY REVIEW ANIONS [-] Cl-, HCO3-, PO4 3- CATIONS [+]; Na+, K+ Ca+, Mg SOLUTE e.g. electrolyte SOLVENT e.g. water DIFFUSION: random movement of solute equalizes distribution of solute FILTRATION: water and ‘lytes move together across membrane under pressure; capillaries NRS 105 Collings 2011

7. VOCABULARY REVIEW • OSMOSIS: movement of H2O across membrane [less to more] to equalize ion concentration • OSMOTIC PRESSURE: drawing power to H2O; albumin pulls H2O into intravascular space • ISOTONIC: same osmolarity as plasma; NS • HYPERTONIC: higher osmotic pressure – pulls fluid from cells • HYPOTONIC: low osmotic pressure; 0.45% NS moves fluid into cells • HYDROSTATIC PRESSURE: determines direction of filtration – high to low [capillaries] NRS 105 Collings 2011

8. OSMOSIS MOVEMENT OF A SOLVENT (WATER) ACROSS A SEMIPERMEABLE MEMBRANE MOVES FROM AN AREA OF LESSER SOLUTE CONCENTRATION (ELECTROLYTE) TO AN AREA OF GREATER SOLUTE CONTRATION NRS 105 Collings 2011

9. NRS 105 Collings 2011

10. OSMOTIC PRESSURE THE DRAWING POWER OF WATER A HIGHLY CONCENTRATED FLUID HAS HIGH OSMOTIC PRESSURE – DRAWS WATER TO IT WORKS TO ATTAIN EQUILIBRIUM (BALANCE) OSMOLARITY DESCRIBES THE CONCENTRATION OF SOLUTIONS – THE NUMBER OF MOLECULES PER LITER OF SOLUTION NRS 105 Collings 2011

11. IV SOLUTIONS ISOTONIC SOLUTIONS THE SAME CONCENTRATION (OSMOLARITY) AS BLOOD PLASMA e.g. NS 0.9% no change; ↑volume HYPOTONIC SOLUTION A SOLUTION OF LOWER OSMOTIC PRESSURE – LOWER CONCENTRATION OF SOLUTES THAN BLOOD PLASMA e.g. ½ NS 0.45%, pulls fluid out of cells HYPERTONIC SOLUTION A SOLUTION OF HIGHER OSMOTIC PRESSURE (MORE CONCENTRATED THAN BLOOD PLASMA) e.g. D5NS – pulls fluid from cells NRS 105 Collings 2011

12. DIFFUSION RANDOM MOVEMENT OF A SOLUTE (ELECTROLYTE, GAS) ACROSS A SEMI-PERMEABLE MEMBRANE CREAM IN COFFEE OXYGEN, CARBON DIOXIDE BETWEEN ALVEOLI AND BLOOD VESSELS MOVES FROM AREAS OF HIGH CONCENTRATION TO AN AREA OF LOWER CONCENTRATION ACROSS A CONCENTRATION GRADIENT NRS 105 Collings 2011

13. NRS 105 Collings 2011 NRS 105.320 W2009

14. ACTIVE TRANSPORT REQUIRES METABOLIC ACTIVITY AND USES ENERGY TO MOVE SUBSTANCES ACROSS CELL MEMBRANES. ENABLES LARGER SUBSTANCES TO MOVE INTO CELLS MOLECULES CAN ALSO MOVE TO AN AREA OF HIGHER CONCENTRATION (UPHILL) SODIUM, POTASSIUM PUMP POTASSIUM PUMPED IN SODIUM PUMPED OUT NRS 105 Collings 2011

15. NRS 105 Collings 2011

16. FILTRATION WATER AND SUBSTANCES MOVE TOGETHER ACROSS A MEMBRANE BECAUSE OF FLUID PRESSURE OCCURS IN CAPILLARY BEDS MOVEMENT FROM AN AREA OF HIGHER PRESSURE TO AN AREA OF LOWER PRESSURE (HYDROSTATIC PRESSURE) B/P changes – e.g. hemorrhage, ICP NRS 105 Collings 2011

17. NRS 105 Collings 2011

18. REGULATION OF BODY FLUIDS HOMEOSTASIS IS MAINTAINED THROUGH FLUID INTAKE HORMONAL REGULATION FLUID OUTPUT NRS 105 Collings 2011

19. FLUID INTAKE Thirst control center located in the hypothalamus Osmoreceptors monitor serum osmolarity When osmolarity increases [blood more concentrated] thirst sensation Salt increases serum osmolarity Protective against dehydration High glucose also increases serum osmolarity Symptoms of diabetes NRS 105 Collings 2011

20. FLUID INTAKE AVERAGE ADULT INTAKE 2200 – 2700 ml PER DAY ORAL 1100 – 1400 ml PER DAY SOLID FOODS 800 – 1000 ml PER DAY OXIDATIVE METABOLISM – 300 ml PER DAY NRS 105 Collings 2011

21. HORMONAL REGULATION ADH (ANTIDIURETIC HORMONE) STORED IN THE POSTERIOR PITUITARY AND RELEASED IN RESPONSE TO SERUM OSMOLARITY Prevents diuresis – saves water PAIN, STRESS, CIRCULATING BLOOD VOLUME AFFECT THE RELEASE OF ADH ↑ IN ADH = ↓ IN URINE OUTPUT NRS 105 Collings 2011

22. HORMONAL REGULATION RENIN-ANGIOTENSIN-ALDOSTERONE INITIATED BY A CHANGE IN RENAL PERFUSION RENIN, PRODUCED BY KIDNEYS, IS RELEASED IN RESPONSE TO LOW PERFUSION RELATED TO A DECREASE IN EXTRACELLULAR VOLUME RENIN PRODUCES ANGIOTENSIN I ANGIOTENSIN I QUICKLY COVERTED TO ANGIOTENSIN II ANGIOTENSIN II IS A POTENT selective VASOCONSTRICTOR ALSO INCREASES RENAL PERFUSION ↑ blood flow to kidneys Stimulate release of Aldosterone NRS 105 Collings 2011

23. HORMONAL REGULATION ALDOSTERONE ACTS ON THE DISTAL PROTION OF THE RENAL TUBLES TO INCREASE THE REABSORPTION OF SODIUM AND THE SECRETION AND EXCRETION OF POTASSIUM AND HYDROGEN WATER IS RETAINED BECAUSE SODIUM IS RETAINED Sodium & water retained → restored blood volume [protective] HTN, plaque, etc same cycle [edema] NRS 105 Collings 2011

24. HORMONAL REGULATION ATRIAL NATRIURETIC PEPTIDE (ANP) ANP IS A HORMONE SECRETED FROM ATRIAL CELLS OF THE HEART IN RESPONSE TO ATRIAL STRETCHING AND AN INCREASE IN CIRCULATING BLOOD VOLUME ANP acts as a diuretic, causes Na+ loss, inhibits thirst decreased blood volume Protective if blood volume high Not protective in cardiac disease [Na+ imbalance] NRS 105 Collings 2011

25. FLUID OUTPUT REGULATION ORGANS OF WATER LOSS KIDNEY LUNGS SKIN GI TRACT NRS 105 Collings 2011

26. FLUID OUTPUT REGULATION KIDNEYS MAJOR REGULATORY ORGANS OF FLUID BALANCE RECEIVE ABOUT 180 LITERS OF PLASMA TO FILTER EACH DAY 1200 – 1500 ml OF URINE PRODUCED EACH DAY URINE VOLUME CHANGES RELATED TO VARIATION ON THE AMOUNT AND TYPE OF FLUIDS INGESTED Minimum volume of urine to excrete wastes [e.g. urea] is about 400 ml/ day NRS 105 Collings 2011

27. FLUID OUTPUT REGULATION SKIN INSENSIBLE WATER LOSS OCCURS THROUGH THE SKIN AND LUNGS SENSIBLE WATER LOSS EXCESS PERSPIRATION (CAN BE SENSIBLE OR INSENSIBLE) INSENSIBLE + SENSIBLE FLUID LOSS THROUGH THE SKIN 500 – 600ml EACH DAY NRS 105 Collings 2011

28. FLUID OUTPUT REGULATION LUNGS EXPIRE APPROXIMATELY 500 ml OF WATER DAILY INCEASE IN WATER LOSS RELATED TO ADMINISTRATION OF OXYGEN Clients on high O2 need extra fluids to compensate NRS 105 Collings 2011

29. FLUID OUTPUT REGULATION GI TRACT 3 – 6 LITERS OF ISOTONIC FLUID MOVES INTO THE GI TRACT AND THEN RETURNS TO THE EXTRACELLULAR FLUID SPACE Vomiting increases GI losses + electrolytes 200 ml OF FLUID IS LOST IN THE FECES EACH DAY DIARRHEA CAN INCREASE THIS LOSS NRS 105 Collings 2011

30. REGULATION OF ELECTROLYTES MAJOR CATIONS IN BODY FLUIDS SODIUM (Na+) POTASSIUM (K+) CALCIUM (Ca++) MAGNESIUM (Mg++) NRS 105 Collings 2011

31. REGULATION OF ELECTROLYTES SODIUM REGULATION MOST ABUNDANT CATION IN THE EXTRACELLULAR FLUID MAJOR CONTRIBUTOR TO MAINTAINING WATER BALANCE NERVE TRANSMISSION ** LOC, peripheral REGULATION OF ACID-BASE BALANCE CONTRIBUTES TO CELLULAR CHEMICAL REACTIONS SODIUM IS TAKEN IN VIA FOOD AND BALANCE IS MAINTAINED THROUGH ALDOSTERONE NRS 105 Collings 2011

32. REGULATION OF ELECTROLYTES POTASSIUM REGULATION MAJOR ELECTROLYTE AND PRINCIPLE CATION IN THE INTRACELLULAR FLUID REGULATES METABOLIC ACTIVITIES REQUIRED FOR GLYCOGEN DEPOSITS IN THE LIVER AND SKELETAL MUSCLE REQUIRED FOR TRANSMISSION OF NERVE IMPULSES, NORMAL CARDIAC CONDUCTION AND NORMAL SMOOTH AND SKELETAL MUSCLE CONTRACTION REGULATED BY DIETARY INTAKE AND RENAL EXCRETION NRS 105 Collings 2011

33. REGULATION OF ELECTROLYTES CALCIUM REGULATION STORED IN THE BONE, PLASMA AND BODY CELLS 99% OF CALCIUM IS IN THE BONES AND TEETH 1% IS IN EXTRACELLULAR FLUID 50% OF CALCIUM IN THE EXTRACELLULAR FLUID IS BOUND TO PROTEIN (ALBUMIN) 40% IS FREE IONIZED CALCIUM May be measured as Ionized or total Ca NRS 105 Collings 2011

34. REGULATION OF ELECTROLYTES CALCIUM REGULATION CALCIUM IS NECESSARY FOR BONE AND TEETH FORMATION BLOOD CLOTTING HORMONE SECRETION CELL MEMBRANE INTEGRITY CARDIAC CONDUCTION TRANSMISSION OF NERVE IMPULSES MUSCLE CONTRACTION NRS 105 Collings 2011

35. REGULATION OF ELECTROLYTES MAGNESIUM ESSENTIAL FOR ENZYME ACTIVITIES NEUROCHEMICAL ACTIVITIES CARDIAC AND SKELETAL MUSCLE EXCITABILITY REGULATION DIETARY RENAL PARATHYROID HORMONE 50 – 60% OF MAGNESIUM CONTAINED IN BONES 1% IN EXTRACELLULAR FLUID;MINIMAL AMOUNT IN CELL NRS 105 Collings 2011

36. REGULATION OF ELECTROLYTES ANIONS CHLORIDE (Cl-) BICARBONATE (HCO3-) PHOSPHATE (PO4---) NRS 105 Collings 2011

37. REGULATION OF ELECTROLYTES CHLORIDE REGULATION MAJOR ANION IN ECF CHLORIDE FOLLOWS SODIUM REGULATED BY DIETARY INTAKE AND THE KIDNEYS NRS 105 Collings 2011

38. REGULATION OF ELECTROLYTES • BICARBONATE REGULATION • MAJOR CHEMICAL BUFFER WITHIN THE BODY • FOUND IN BOTH ECF AND ICF • ESSENTIAL TO ACID-BASE BALANCE • REGULATED BY THE KIDNEYS NRS 105 Collings 2011

39. REGULATION OF ELECTROLYTES • PHOSPHORUS – PHOSPHATE REGULATION (TERMS USED INTERCHANGEABLY) • BUFFER ANION FOUND MOSTLY IN ECF • MAINTAINS BONES AND TEETH • INVERSE RELATIONSHIP BETWEEN PHOSPHATE AND CALCIUM • PHOSPHATE ALSO PROMOTES NORMAL NEUROMUSCULAR FUNCTION NRS 105 Collings 2011

40. REGULATION OF ACID-BASE BALANCE • VOCABULARY • BUFFER • A SUBSTANCE THAT CAN EITHER ABSORB OR RELEASE A HYDROGEN ION (H+) • ARTERIAL pH REFLECTS THE CONCENTRATION OF HYDROGEN IONS IN THE BLOOD • THE pH SCALE • MEASURES THE ACIDITY OR ALKALINITY OF A FLUID • NORMAL RANGE FOR ARTERIAL BLOOD 7.35 – 7.45 NRS 105 Collings 2011

41. REGULATION OF ACID-BASE BALANCE • BIOLOGICAL REGULATION OF Ph • BUFFERING SYSTEMS • HYDROGEN IONS ARE ABSORBED OR RELEASED BY THE CELLS • SWITCH PLACES WITH POTASSIUM • HEMOGLOBIN-OXYHEMOGLOBIN SYSTEM • CHLORIDE SHIFT WITHIN RBCs NRS 105 Collings 2011

42. REGULATION OF ACID-BASE BALANCE • PHYSIOLOGICAL: Lungs, Kidneys • LUNGS Early response • ↑ HYDROGEN & CARBON DIOXIDE [acidosis] Stimulates ↑ Respiratory rate, depth → exhaled CO2 • ↓ Co2 & H+ [alkalosis] → retain CO2 by ↓RR • EXAMPLES • DIABETIC KETOACIDOSIS • CO2 RETAINING PATIENTS WITH COPD NRS 105 Collings 2011

43. Acid – Base Regulation - Kidneys • Takes longer/lasts longer • Hours to days • Increased or decreased production of Bicarb, excretion of H+ by ammonia formation, phosphoric acid • Acid excess [acidosis] → reabsorption of bicarb, • Phosphate + H+ = H3PO4 and NH3- + H+ = NH4 → excretion of H+, lowers acid NRS 105 Collings 2011

44. ELECTROLYTE IMBALANCES • SODIUM IMBALANCE • HYPONATREMIA [< 135mEq/L serum Na] • GI LOSSES [vomiting/diarrhea] • KIDNEY DISEASE • SKIN LOSS – PERSPIRATION • PSYCHOGENIC POLYDYPSIA • SIADH (SYNDROME OF INAPPROPRIATE ADH) NRS 105 Collings 2011

45. ELECTROLYTE IMBALANCES • SODIUM IMBALANCES • HYPERNATREMIA [>145mEq/L] • EXCESS SALT INTAKE • INFUSION OF HYPERTONIC SALINE ( 3%, 5%) • EXCESS ALDOSTERONE • DIABETES INSIPIDUS [low ADH/thirst/dilute urine excreted – Na+ not excreted] • DEHYDRATION [H2O follows Na+, but Na+ does not follow H2O] NRS 105 Collings 2011

46. ELECTROLYTE IMBALANCES • POTASSIUM • HYPOKALEMIA [<3.5mEq/L] • Common, affects cardiac conductivity/ function • POTASSIUM WASTING DIURETICS • DIARRHEA, VOMITING • ALKALOSIS [shifts into cells in exchange for H+] • EXCESSIVE ALDOSTERONE SECRETION • POLYURIA • EXCESSIVE PERSPIRATION • TREATMENT OF DKA WITH INSULIN [decreases serum potassium by redistributing it into cells] NRS 105 Collings 2011

47. ELECTROLYTE IMBALANCES • POTASSIUM K+ • HYPERKALEMIA [>5mEq/L] • Cardiac conduction, altered ECG, arrest • RENAL FAILURE • FLUID VOLUME DEFICIT • CELL DAMAGE FROM BURNS, TRAUMA • ADRENAL INSUFFICIENCY • RAPID INFUSION OF STORED BLOOD • POTASSIUM SPARING DIURETICS • SALT SUBSTITUTES NRS 105 Collings 2011

48. ELECTROLYTE IMBALANCES • Hypocalcemia [ionized Ca < 4.5 mEq/L OR total serum Ca < 8.5mEq/L] • Illnesses affecting thyroid, parathyroid • Renal failure [not excreting Phosphate] alcoholics, pancreatitis • Neuromuscular and Cardiac sx • ↑↑reflexes, cramps, numbness/tingling NRS 105 Collings 2011

49. ELECTROLYTE IMBALANCES • Hypercalcemia [serum Ionized Ca+ > 5.5 or total serum Ca > 10.5 mEq/L] • Immobility, osteoporosis, neoplasm → bone loss of Ca into blood • Kidney stones, ↓ reflexes, N&V NRS 105 Collings 2011

50. ELECTROLYTE IMBALANCES • Magnesium [1.5-2.5 mEq/L] • Malnutrition, malabsorption → ↓Mg [looks like ↓Ca] ↓ ↓ - Mg hyperactive reflexes • Excess intake + renal problems → ↑Mg, ↓HR, RR, B/P, DTR ↓ [e.g. Sulfate in L&D] • Chloride • Follows Na+, Acid/base imbalance NRS 105 Collings 2011