FLUIDS, ELECTROLYTES, WATER AND ACID – BASE BALANCE

NRS 105 Collings 2011NRS 105 Collings 201104/22/23 1

FLUIDS, ELECTROLYTES, FLUIDS, ELECTROLYTES, WATER AND WATER AND

ACID – BASE BALANCEACID – BASE BALANCE


DISTRIBUTION OF BODY DISTRIBUTION OF BODY FLUIDSFLUIDS

• INTRACELLULARINTRACELLULAR– INSIDE THE CELLINSIDE THE CELL

• EXTRACELLULAREXTRACELLULAR– OUTSIDE THE CELLOUTSIDE THE CELL

•INTRAVASCULARINTRAVASCULAR– INSIDE THE VESSELS (ARTERIES AND VEINS)INSIDE THE VESSELS (ARTERIES AND VEINS)

•INTERSTITIALINTERSTITIAL– NOT IN THE CELL, NOT IN THE VESSELSNOT IN THE CELL, NOT IN THE VESSELS– BETWEEN THE CELL (contains LYMPH)BETWEEN THE CELL (contains LYMPH)

•TRANSCELLULARTRANSCELLULAR– CSF, PLEURAL FLUID, INTRAOCCULAR, GI, CSF, PLEURAL FLUID, INTRAOCCULAR, GI,

PERITONEAL, SYNOVIALPERITONEAL, SYNOVIAL


BODY FLUID BODY FLUID COMPARTMENTS COMPARTMENTS


ELECTROLYTES IN BODY ELECTROLYTES IN BODY FLUIDSFLUIDS

• NORMAL VALUESNORMAL VALUES– SODIUM (Na+)SODIUM (Na+) 135–145 mEq/L135–145 mEq/L– POTASSIUMPOTASSIUM (K+)(K+) 3.5 – 5.0 mEq/L3.5 – 5.0 mEq/L– IONIZED CALCIUM (Ca++)IONIZED CALCIUM (Ca++) 4.5 – 5.5mg/dl4.5 – 5.5mg/dl

– BICARBONATE (HCOBICARBONATE (HCO33)) 22 – 26 mEq/L22 – 26 mEq/L

– CHLORIDE (ClCHLORIDE (Cl----)) 95 – 105mEq/L95 – 105mEq/L– MAGNESIUM (Mg++)MAGNESIUM (Mg++) 1.5 – 2.5mEq/L1.5 – 2.5mEq/L

– PHOSPHATE (POPHOSPHATE (PO44------)) 2.8 – 4.5mg/dl2.8 – 4.5mg/dl


MEASUREMENTS OF MEASUREMENTS OF ELECTROLYTESELECTROLYTES

• mEq/L mEq/L – MILLIEQUIVALENTS PER LITERMILLIEQUIVALENTS PER LITER– THE NUMBER OF GRAMS OF A GIVEN THE NUMBER OF GRAMS OF A GIVEN

ELECTROLYTE DISSOLVED IN A LITER OF ELECTROLYTE DISSOLVED IN A LITER OF PLASMAPLASMA


VOCABULARY REVIEWVOCABULARY 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 2011NRS 105 Collings 2011

VOCABULARY REVIEWVOCABULARY REVIEW• OSMOSIS: movement of H2O across OSMOSIS: movement of H2O across

membrane [less to more] to equalize ion membrane [less to more] to equalize ion concentrationconcentration

• OSMOTIC PRESSURE: drawing power to H2O; OSMOTIC PRESSURE: drawing power to H2O; albumin pulls H2O into intravascular space albumin pulls H2O into intravascular space

• ISOTONIC: same osmolarity as plasma; NSISOTONIC: same osmolarity as plasma; NS• HYPERTONIC: higher osmotic pressure – pulls HYPERTONIC: higher osmotic pressure – pulls

fluid from cellsfluid from cells• HYPOTONIC: low osmotic pressure; 0.45% NS HYPOTONIC: low osmotic pressure; 0.45% NS

moves fluid into cellsmoves fluid into cells• HYDROSTATIC PRESSURE: determines HYDROSTATIC PRESSURE: determines

direction of filtration – high to low [capillaries] direction of filtration – high to low [capillaries]

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OSMOSISOSMOSIS

• MOVEMENT OF A SOLVENT (WATER) MOVEMENT OF A SOLVENT (WATER) ACROSS A SEMIPERMEABLE ACROSS A SEMIPERMEABLE MEMBRANEMEMBRANE

• MOVES FROM AN AREA OF LESSER MOVES FROM AN AREA OF LESSER SOLUTE CONCENTRATION SOLUTE CONCENTRATION (ELECTROLYTE) TO AN AREA OF (ELECTROLYTE) TO AN AREA OF GREATER SOLUTE CONTRATIONGREATER SOLUTE CONTRATION


OSMOTIC PRESSUREOSMOTIC PRESSURE

• THE DRAWING POWER OF WATERTHE DRAWING POWER OF WATER– A HIGHLY CONCENTRATED FLUID HAS A HIGHLY CONCENTRATED FLUID HAS

HIGH OSMOTIC PRESSURE – DRAWS HIGH OSMOTIC PRESSURE – DRAWS WATER TO ITWATER TO IT•WORKS TO ATTAIN EQUILIBRIUM (BALANCE)WORKS TO ATTAIN EQUILIBRIUM (BALANCE)

• OSMOLARITYOSMOLARITY– DESCRIBES THE CONCENTRATION OF DESCRIBES THE CONCENTRATION OF

SOLUTIONS – THE NUMBER OF SOLUTIONS – THE NUMBER OF MOLECULES PER LITER OF SOLUTIONMOLECULES PER LITER OF SOLUTION


IV SOLUTIONSIV SOLUTIONS• ISOTONIC SOLUTIONSISOTONIC SOLUTIONS

– THE SAME CONCENTRATION (OSMOLARITY) AS BLOOD PLASMA e.g. NS 0.9% no change; ↑volume

• HYPOTONIC SOLUTIONHYPOTONIC 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 SOLUTIONHYPERTONIC SOLUTION– A SOLUTION OF HIGHER OSMOTIC PRESSURE

(MORE CONCENTRATED THAN BLOOD PLASMA) e.g. D5NS – pulls fluid from cells


DIFFUSIONDIFFUSION

• RANDOM MOVEMENT OF A SOLUTE RANDOM MOVEMENT OF A SOLUTE (ELECTROLYTE, GAS) ACROSS A SEMI-(ELECTROLYTE, GAS) ACROSS A SEMI-PERMEABLE MEMBRANEPERMEABLE MEMBRANE– CREAM IN COFFEECREAM IN COFFEE– OXYGEN, CARBON DIOXIDE BETWEEN OXYGEN, CARBON DIOXIDE BETWEEN

ALVEOLI AND BLOOD VESSELSALVEOLI AND BLOOD VESSELS•MOVES FROM AREAS OF HIGH CONCENTRATION MOVES FROM AREAS OF HIGH CONCENTRATION

TO AN AREA OF LOWER CONCENTRATION TO AN AREA OF LOWER CONCENTRATION ACROSS A CONCENTRATION GRADIENTACROSS A CONCENTRATION GRADIENT

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ACTIVE TRANSPORTACTIVE TRANSPORT• REQUIRES METABOLIC ACTIVITY AND REQUIRES METABOLIC ACTIVITY AND

USES ENERGY TO MOVE SUBSTANCES USES ENERGY TO MOVE SUBSTANCES ACROSS CELL MEMBRANES.ACROSS CELL MEMBRANES.– ENABLES LARGER SUBSTANCES TO MOVE ENABLES LARGER SUBSTANCES TO MOVE

INTO CELLSINTO CELLS– MOLECULES CAN ALSO MOVE TO AN AREA MOLECULES CAN ALSO MOVE TO AN AREA

OF HIGHER CONCENTRATION (UPHILL)OF HIGHER CONCENTRATION (UPHILL)– SODIUM, POTASSIUM PUMP SODIUM, POTASSIUM PUMP

•POTASSIUM PUMPED INPOTASSIUM PUMPED IN•SODIUM PUMPED OUTSODIUM PUMPED OUT


FILTRATIONFILTRATION

• WATER AND SUBSTANCES MOVE WATER AND SUBSTANCES MOVE TOGETHER ACROSS A MEMBRANE TOGETHER ACROSS A MEMBRANE BECAUSE OF FLUID PRESSUREBECAUSE OF FLUID PRESSURE– OCCURS IN CAPILLARY BEDSOCCURS IN CAPILLARY BEDS– MOVEMENT FROM AN AREA OF HIGHER MOVEMENT FROM AN AREA OF HIGHER

PRESSURE TO AN AREA OF LOWER PRESSURE TO AN AREA OF LOWER PRESSURE (HYDROSTATIC PRESSURE)PRESSURE (HYDROSTATIC PRESSURE)

– B/P changes – e.g. hemorrhage, ICP B/P changes – e.g. hemorrhage, ICP


REGULATION OF BODY REGULATION OF BODY FLUIDSFLUIDS

• HOMEOSTASIS IS MAINTAINED HOMEOSTASIS IS MAINTAINED THROUGHTHROUGH– FLUID INTAKEFLUID INTAKE– HORMONAL REGULATIONHORMONAL REGULATION– FLUID OUTPUTFLUID OUTPUT


FLUID INTAKEFLUID INTAKE

• Thirst control center located in the Thirst control center located in the hypothalamushypothalamus– Osmoreceptors monitor serum osmolarityOsmoreceptors monitor serum osmolarity– When osmolarity increases [blood more When osmolarity increases [blood more

concentrated]concentrated] thirst sensation thirst sensation•Salt increases serum osmolaritySalt increases serum osmolarity

– Protective against dehydrationProtective against dehydration

•High glucose also increases serum osmolarityHigh glucose also increases serum osmolarity– Symptoms of diabetesSymptoms of diabetes


FLUID INTAKEFLUID INTAKE

• AVERAGE ADULT INTAKE AVERAGE ADULT INTAKE – 2200 – 2700 ml PER DAY2200 – 2700 ml PER DAY

•ORAL 1100 – 1400 ml PER DAYORAL 1100 – 1400 ml PER DAY

•SOLID FOODS 800 – 1000 ml PER DAYSOLID FOODS 800 – 1000 ml PER DAY

•OXIDATIVE METABOLISM – 300 ml PER DAY OXIDATIVE METABOLISM – 300 ml PER DAY


HORMONAL REGULATIONHORMONAL REGULATION

• ADH (ANTIDIURETIC HORMONE)ADH (ANTIDIURETIC HORMONE)– STORED IN THE POSTERIOR PITUITARY STORED IN THE POSTERIOR PITUITARY

AND RELEASED IN RESPONSE TO SERUM AND RELEASED IN RESPONSE TO SERUM OSMOLARITYOSMOLARITY

– Prevents diuresis – saves waterPrevents diuresis – saves water– PAIN, STRESS, CIRCULATING BLOOD PAIN, STRESS, CIRCULATING BLOOD

VOLUME AFFECT THE RELEASE OF ADHVOLUME AFFECT THE RELEASE OF ADH• ↑ ↑ IN ADH = IN ADH = ↓ ↓ IN URINE OUTPUTIN URINE OUTPUT


HORMONAL REGULATIONHORMONAL REGULATION• RENIN-ANGIOTENSIN-ALDOSTERONE RENIN-ANGIOTENSIN-ALDOSTERONE

– INITIATED BY A CHANGE IN RENAL PERFUSIONINITIATED BY A CHANGE IN RENAL PERFUSION•RENIN, PRODUCED BY KIDNEYS, IS RELEASED IN RENIN, PRODUCED BY KIDNEYS, IS RELEASED IN

RESPONSE TO LOW PERFUSION RELATED TO A RESPONSE TO LOW PERFUSION RELATED TO A DECREASE IN EXTRACELLULAR VOLUMEDECREASE IN EXTRACELLULAR VOLUME

– RENIN PRODUCES ANGIOTENSIN IRENIN PRODUCES ANGIOTENSIN I– ANGIOTENSIN I QUICKLY COVERTED TO ANGIOTENSIN IIANGIOTENSIN I QUICKLY COVERTED TO ANGIOTENSIN II– ANGIOTENSIN II IS A POTENT ANGIOTENSIN II IS A POTENT selectiveselective

VASOCONSTRICTORVASOCONSTRICTOR– ALSO INCREASES RENAL PERFUSIONALSO INCREASES RENAL PERFUSION

• ↑ ↑ blood flow to kidneysblood flow to kidneys

• Stimulate release of AldosteroneStimulate release of Aldosterone


HORMONAL REGULATIONHORMONAL REGULATION• ALDOSTERONEALDOSTERONE

– ACTS ON THE DISTAL PROTION OF THE ACTS ON THE DISTAL PROTION OF THE RENAL TUBLES TO INCREASE THE RENAL TUBLES TO INCREASE THE REABSORPTION OF SODIUM AND THE REABSORPTION OF SODIUM AND THE SECRETION AND EXCRETION OF SECRETION AND EXCRETION OF POTASSIUM AND HYDROGENPOTASSIUM AND HYDROGEN

– WATER IS RETAINED BECAUSE SODIUM IS RETAINED

– Sodium & water retained Sodium & water retained → restored blood → restored blood volume [protective]volume [protective]

– HTN, plaque, etcHTN, plaque, etc same cycle [edema] same cycle [edema]


HORMONAL REGULATIONHORMONAL REGULATION• ATRIAL NATRIURETIC PEPTIDE (ANP)ATRIAL NATRIURETIC PEPTIDE (ANP)

– ANP IS A HORMONE SECRETED FROM ATRIAL ANP IS A HORMONE SECRETED FROM ATRIAL CELLS OF THE HEART IN RESPONSE TO CELLS OF THE HEART IN RESPONSE TO ATRIAL STRETCHING AND AN INCREASE IN ATRIAL STRETCHING AND AN INCREASE IN CIRCULATING BLOOD VOLUMECIRCULATING BLOOD VOLUME

– ANP acts as a diuretic, causes Na+ loss, ANP acts as a diuretic, causes Na+ loss, inhibits thirst inhibits thirst decreased blood volumedecreased blood volume•Protective if blood volume highProtective if blood volume high

•Not protective in cardiac disease [Na+ Not protective in cardiac disease [Na+ imbalance]imbalance]


FLUID OUTPUT REGULATIONFLUID OUTPUT REGULATION

• ORGANS OF WATER LOSSORGANS OF WATER LOSS– KIDNEYKIDNEY– LUNGSLUNGS– SKINSKIN– GI TRACTGI TRACT


FLUID OUTPUT REGULATIONFLUID OUTPUT REGULATION• KIDNEYSKIDNEYS

– MAJOR REGULATORY ORGANS OF FLUID BALANCE•RECEIVE ABOUT 180 LITERS OF PLASMA TO RECEIVE ABOUT 180 LITERS OF PLASMA TO

FILTER EACH DAYFILTER EACH DAY•1200 – 1500 ml OF URINE PRODUCED EACH 1200 – 1500 ml OF URINE PRODUCED EACH

DAYDAY•URINE VOLUME CHANGES RELATED TO URINE VOLUME CHANGES RELATED TO

VARIATION ON THE AMOUNT AND TYPE OF VARIATION ON THE AMOUNT AND TYPE OF FLUIDS INGESTEDFLUIDS INGESTED

•Minimum volume of urine to excrete wastes Minimum volume of urine to excrete wastes [e.g. urea] is about 400 ml/ day[e.g. urea] is about 400 ml/ day



• SKINSKIN– INSENSIBLE WATER LOSSINSENSIBLE WATER LOSS

•OCCURS THROUGH THE SKIN AND LUNGSOCCURS THROUGH THE SKIN AND LUNGS

– SENSIBLE WATER LOSSSENSIBLE WATER LOSS•EXCESS PERSPIRATION (CAN BE SENSIBLE EXCESS PERSPIRATION (CAN BE SENSIBLE

OR INSENSIBLE)OR INSENSIBLE)

– INSENSIBLE + SENSIBLE FLUID LOSS INSENSIBLE + SENSIBLE FLUID LOSS THROUGH THE SKINTHROUGH THE SKIN

– 500 – 600ml EACH DAY500 – 600ml EACH DAY



• LUNGSLUNGS– EXPIRE APPROXIMATELY 500 ml OF EXPIRE APPROXIMATELY 500 ml OF

WATER DAILYWATER DAILY• INCEASE IN WATER LOSS RELATED TO INCEASE IN WATER LOSS RELATED TO

ADMINISTRATION OF OXYGENADMINISTRATION OF OXYGEN

•Clients on high O2 need extra fluids to Clients on high O2 need extra fluids to compensatecompensate



• GI TRACTGI TRACT– 3 – 6 LITERS OF ISOTONIC FLUID MOVES 3 – 6 LITERS OF ISOTONIC FLUID MOVES

INTO THE GI TRACT AND THEN RETURNS INTO THE GI TRACT AND THEN RETURNS TO THE EXTRACELLULAR FLUID SPACETO THE EXTRACELLULAR FLUID SPACE•Vomiting increases GI losses + electrolytesVomiting increases GI losses + electrolytes

– 200 ml OF FLUID IS LOST IN THE FECES 200 ml OF FLUID IS LOST IN THE FECES EACH DAYEACH DAY•DIARRHEA CAN INCREASE THIS LOSS DIARRHEA CAN INCREASE THIS LOSS


REGULATION OF REGULATION OF ELECTROLYTESELECTROLYTES

• MAJOR CATIONS IN BODY FLUIDSMAJOR CATIONS IN BODY FLUIDS– SODIUM (Na+)SODIUM (Na+)– POTASSIUM (K+)POTASSIUM (K+)– CALCIUM (Ca++)CALCIUM (Ca++)– MAGNESIUM (Mg++)MAGNESIUM (Mg++)



• SODIUM REGULATIONSODIUM REGULATION– MOST ABUNDANT CATION IN THE MOST ABUNDANT CATION IN THE

EXTRACELLULAR FLUIDEXTRACELLULAR FLUID– MAJOR CONTRIBUTOR TO MAINTAINING WATER MAJOR CONTRIBUTOR TO MAINTAINING WATER

BALANCEBALANCE•NERVE TRANSMISSION ** LOC, peripheralNERVE TRANSMISSION ** LOC, peripheral

•REGULATION OF ACID-BASE BALANCEREGULATION OF ACID-BASE BALANCE

•CONTRIBUTES TO CELLULAR CHEMICAL REACTIONSCONTRIBUTES TO CELLULAR CHEMICAL REACTIONS

– SODIUM IS TAKEN IN VIA FOOD AND BALANCE IS SODIUM IS TAKEN IN VIA FOOD AND BALANCE IS MAINTAINED THROUGH ALDOSTERONEMAINTAINED THROUGH ALDOSTERONE


REGULATION OF ELECTROLYTESREGULATION OF ELECTROLYTES

• POTASSIUM REGULATIONPOTASSIUM REGULATION– MAJOR ELECTROLYTE AND PRINCIPLE

CATION IN THE INTRACELLULAR FLUID– REGULATES METABOLIC ACTIVITIESREGULATES METABOLIC ACTIVITIES– REQUIRED FOR GLYCOGEN DEPOSITS IN THE REQUIRED FOR GLYCOGEN DEPOSITS IN THE

LIVER AND SKELETAL MUSCLELIVER AND SKELETAL MUSCLE– REQUIRED FOR TRANSMISSION OF NERVE REQUIRED FOR TRANSMISSION OF NERVE

IMPULSES, NORMAL CARDIAC CONDUCTION AND IMPULSES, NORMAL CARDIAC CONDUCTION AND NORMAL SMOOTH AND SKELETAL MUSCLE NORMAL SMOOTH AND SKELETAL MUSCLE CONTRACTIONCONTRACTION

– REGULATED BY DIETARY INTAKE AND RENAL REGULATED BY DIETARY INTAKE AND RENAL EXCRETIONEXCRETION



• CALCIUM REGULATIONCALCIUM REGULATION– STORED IN THE BONE, PLASMA AND BODY STORED IN THE BONE, PLASMA AND BODY

CELLSCELLS•99% OF CALCIUM IS IN THE BONES AND TEETH99% OF CALCIUM IS IN THE BONES AND TEETH

•1% IS IN EXTRACELLULAR FLUID1% IS IN EXTRACELLULAR FLUID– 50% OF CALCIUM IN THE EXTRACELLULAR FLUID IS 50% OF CALCIUM IN THE EXTRACELLULAR FLUID IS

BOUND TO PROTEIN (ALBUMIN)BOUND TO PROTEIN (ALBUMIN)

•40% IS FREE IONIZED CALCIUM 40% IS FREE IONIZED CALCIUM

– May be measured as Ionized or total CaMay be measured as Ionized or total Ca



• CALCIUM REGULATIONCALCIUM REGULATION– CALCIUM IS NECESSARY FOR CALCIUM IS NECESSARY FOR

•BONE AND TEETH FORMATIONBONE AND TEETH FORMATION

•BLOOD CLOTTINGBLOOD CLOTTING

•HORMONE SECRETIONHORMONE SECRETION

•CELL MEMBRANE INTEGRITYCELL MEMBRANE INTEGRITY

•CARDIAC CONDUCTIONCARDIAC CONDUCTION

•TRANSMISSION OF NERVE IMPULSESTRANSMISSION OF NERVE IMPULSES

•MUSCLE CONTRACTIONMUSCLE CONTRACTION



• MAGNESIUM MAGNESIUM – ESSENTIAL FOR ENZYME ACTIVITIESESSENTIAL FOR ENZYME ACTIVITIES– NEUROCHEMICAL ACTIVITIESNEUROCHEMICAL ACTIVITIES– CARDIAC AND SKELETAL MUSCLE EXCITABILITYCARDIAC AND SKELETAL MUSCLE EXCITABILITY– REGULATIONREGULATION

•DIETARYDIETARY•RENALRENAL•PARATHYROID HORMONEPARATHYROID HORMONE

– 50 – 60% OF MAGNESIUM CONTAINED IN BONES50 – 60% OF MAGNESIUM CONTAINED IN BONES•1% IN EXTRACELLULAR FLUID;MINIMAL AMOUNT IN 1% IN EXTRACELLULAR FLUID;MINIMAL AMOUNT IN

CELLCELL



• ANIONSANIONS– CHLORIDE (ClCHLORIDE (Cl--))

– BICARBONATE (HCOBICARBONATE (HCO33--))

– PHOSPHATE (POPHOSPHATE (PO44------))



• CHLORIDE REGULATIONCHLORIDE REGULATION– MAJOR ANION IN ECFMAJOR ANION IN ECF– CHLORIDE FOLLOWS SODIUMCHLORIDE FOLLOWS SODIUM– REGULATED BY DIETARY INTAKE AND REGULATED BY DIETARY INTAKE AND

THE KIDNEYSTHE KIDNEYS



• BICARBONATE REGULATIONBICARBONATE REGULATION– MAJOR CHEMICAL BUFFER WITHIN THE MAJOR CHEMICAL BUFFER WITHIN THE

BODYBODY– FOUND IN BOTH ECF AND ICFFOUND IN BOTH ECF AND ICF– ESSENTIAL TO ACID-BASE BALANCEESSENTIAL TO ACID-BASE BALANCE– REGULATED BY THE KIDNEYSREGULATED BY THE KIDNEYS

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• PHOSPHORUS – PHOSPHATE PHOSPHORUS – PHOSPHATE REGULATION (TERMS USED REGULATION (TERMS USED INTERCHANGEABLY)INTERCHANGEABLY)

•BUFFER ANION FOUND MOSTLY IN ECFBUFFER ANION FOUND MOSTLY IN ECF

•MAINTAINS BONES AND TEETHMAINTAINS BONES AND TEETH

• INVERSE RELATIONSHIP BETWEEN INVERSE RELATIONSHIP BETWEEN PHOSPHATE AND CALCIUMPHOSPHATE AND CALCIUM

•PHOSPHATE ALSO PROMOTES NORMAL PHOSPHATE ALSO PROMOTES NORMAL NEUROMUSCULAR FUNCTIONNEUROMUSCULAR FUNCTION

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REGULATION OF REGULATION OF ACID-BASE BALANCEACID-BASE BALANCE

• VOCABULARYVOCABULARY– BUFFERBUFFER

• A SUBSTANCE THAT CAN EITHER ABSORB OR RELEASE A SUBSTANCE THAT CAN EITHER ABSORB OR RELEASE A HYDROGEN ION (H+)A HYDROGEN ION (H+)

– ARTERIAL pH REFLECTS THE CONCENTRATION ARTERIAL pH REFLECTS THE CONCENTRATION OF HYDROGEN IONS IN THE BLOODOF HYDROGEN IONS IN THE BLOOD

– THE pH SCALETHE pH SCALE• MEASURES THE ACIDITY OR ALKALINITY OF A FLUIDMEASURES THE ACIDITY OR ALKALINITY OF A FLUID

• NORMAL RANGE FOR ARTERIAL BLOOD 7.35 – 7.45NORMAL RANGE FOR ARTERIAL BLOOD 7.35 – 7.45

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• BIOLOGICAL REGULATION OF PhBIOLOGICAL REGULATION OF Ph– BUFFERING SYSTEMSBUFFERING SYSTEMS

•HYDROGEN IONS ARE ABSORBED OR HYDROGEN IONS ARE ABSORBED OR RELEASED BY THE CELLSRELEASED BY THE CELLS

– SWITCH PLACES WITH POTASSIUMSWITCH PLACES WITH POTASSIUM

•HEMOGLOBIN-OXYHEMOGLOBIN SYSTEMHEMOGLOBIN-OXYHEMOGLOBIN SYSTEM

•CHLORIDE SHIFT WITHIN RBCsCHLORIDE SHIFT WITHIN RBCs

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• PHYSIOLOGICAL: Lungs, KidneysPHYSIOLOGICAL: Lungs, Kidneys– LUNGS Early response LUNGS Early response

• ↑ ↑ HYDROGEN & CARBON DIOXIDE [acidosis] HYDROGEN & CARBON DIOXIDE [acidosis] Stimulates Stimulates ↑ ↑ Respiratory rate, depth Respiratory rate, depth → exhaled → exhaled CO2CO2

• ↓ ↓ Co2 & H+ [alkalosis] → retain CO2 by ↓RRCo2 & H+ [alkalosis] → retain CO2 by ↓RR

• EXAMPLESEXAMPLES– DIABETIC KETOACIDOSISDIABETIC KETOACIDOSIS– CO2 RETAINING PATIENTS WITH COPDCO2 RETAINING PATIENTS WITH COPD

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Acid – Base Regulation - Acid – Base Regulation - KidneysKidneys• Takes longer/lasts longerTakes longer/lasts longer

– Hours to daysHours to days

• Increased or decreased production of Increased or decreased production of Bicarb, excretion of H+ by ammonia Bicarb, excretion of H+ by ammonia formation, phosphoric acidformation, phosphoric acid

• Acid excess [acidosis] → reabsorption Acid excess [acidosis] → reabsorption of bicarb, of bicarb,

• Phosphate + H+ = H3PO4 and NH3- + Phosphate + H+ = H3PO4 and NH3- + H+ = NH4 → excretion of H+, lowers H+ = NH4 → excretion of H+, lowers acidacid

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ELECTROLYTE IMBALANCESELECTROLYTE IMBALANCES

• SODIUMSODIUM IMBALANCE IMBALANCE– HYPONATREMIAHYPONATREMIA [< 135mEq/L serum Na] [< 135mEq/L serum Na]

•GI LOSSES [vomiting/diarrhea]GI LOSSES [vomiting/diarrhea]

•KIDNEY DISEASEKIDNEY DISEASE

•SKIN LOSS – PERSPIRATIONSKIN LOSS – PERSPIRATION

•PSYCHOGENIC POLYDYPSIAPSYCHOGENIC POLYDYPSIA

•SIADH (SYNDROME OF INAPPROPRIATE ADH)SIADH (SYNDROME OF INAPPROPRIATE ADH)

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• SODIUMSODIUM IMBALANCES IMBALANCES– HYPERNATREMIA HYPERNATREMIA [>145mEq/L][>145mEq/L]

•EXCESS SALT INTAKEEXCESS SALT INTAKE

• INFUSION OF HYPERTONIC SALINE ( 3%, 5%)INFUSION OF HYPERTONIC SALINE ( 3%, 5%)

•EXCESS ALDOSTERONEEXCESS ALDOSTERONE

•DIABETES INSIPIDUS [low ADH/thirst/dilute DIABETES INSIPIDUS [low ADH/thirst/dilute urine excreted – Na+ not excreted]urine excreted – Na+ not excreted]

•DEHYDRATION [H2O follows Na+, but Na+ DEHYDRATION [H2O follows Na+, but Na+ does not follow H2O]does not follow H2O]

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ELECTROLYTE IMBALANCESELECTROLYTE IMBALANCES• POTASSIUMPOTASSIUM

– HYPOKALEMIAHYPOKALEMIA [<3.5mEq/L] [<3.5mEq/L]– Common, affects cardiac conductivity/ functionCommon, affects cardiac conductivity/ function

•POTASSIUM WASTING DIURETICSPOTASSIUM WASTING DIURETICS

•DIARRHEA, VOMITINGDIARRHEA, VOMITING

•ALKALOSIS [shifts into cells in exchange for H+]ALKALOSIS [shifts into cells in exchange for H+]

•EXCESSIVE ALDOSTERONE SECRETIONEXCESSIVE ALDOSTERONE SECRETION

•POLYURIAPOLYURIA

•EXCESSIVE PERSPIRATIONEXCESSIVE PERSPIRATION

•TREATMENT OF DKA WITH INSULIN [decreases serum TREATMENT OF DKA WITH INSULIN [decreases serum potassium by redistributing it into cells]potassium by redistributing it into cells]

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ELECTROLYTE IMBALANCESELECTROLYTE IMBALANCES• POTASSIUM K+POTASSIUM K+

– HYPERKALEMIAHYPERKALEMIA[>5mEq/L][>5mEq/L]– Cardiac conduction, altered ECG, arrestCardiac conduction, altered ECG, arrest

•RENAL FAILURERENAL FAILURE

•FLUID VOLUME DEFICITFLUID VOLUME DEFICIT

•CELL DAMAGE FROM BURNS, TRAUMACELL DAMAGE FROM BURNS, TRAUMA

•ADRENAL INSUFFICIENCYADRENAL INSUFFICIENCY

•RAPID INFUSION OF STORED BLOODRAPID INFUSION OF STORED BLOOD

•POTASSIUM SPARING DIURETICSPOTASSIUM SPARING DIURETICS

•SALT SUBSTITUTESSALT SUBSTITUTES

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• HypocalcemiaHypocalcemia [ionized Ca < 4.5 mEq/L [ionized Ca < 4.5 mEq/L OR total serum Ca < 8.5mEq/L]OR total serum Ca < 8.5mEq/L]

• Illnesses affecting thyroid, parathyroidIllnesses affecting thyroid, parathyroid

• Renal failure [not excreting Phosphate] Renal failure [not excreting Phosphate] alcoholics, pancreatitisalcoholics, pancreatitis

• Neuromuscular and Cardiac sxNeuromuscular and Cardiac sx

• ↑↑↑↑reflexes, cramps, reflexes, cramps, numbness/tinglingnumbness/tingling

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• HypercalcemiaHypercalcemia [serum Ionized Ca+ > [serum Ionized Ca+ > 5.5 or total serum Ca > 10.5 mEq/L]5.5 or total serum Ca > 10.5 mEq/L]– Immobility, osteoporosis, neoplasm → Immobility, osteoporosis, neoplasm →

bone loss of Ca into bloodbone loss of Ca into blood– Kidney stones, ↓ reflexes, N&VKidney stones, ↓ reflexes, N&V

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• MagnesiumMagnesium [1.5-2.5 mEq/L] [1.5-2.5 mEq/L]– Malnutrition, malabsorption → ↓Mg [looks Malnutrition, malabsorption → ↓Mg [looks

like ↓Ca] ↓ ↓ - Mg hyperactive reflexeslike ↓Ca] ↓ ↓ - Mg hyperactive reflexes– Excess intake + renal problems → ↑Mg, Excess intake + renal problems → ↑Mg,

↓HR, RR, B/P, DTR ↓ [e.g. Sulfate in L&D]↓HR, RR, B/P, DTR ↓ [e.g. Sulfate in L&D]

• ChlorideChloride– Follows Na+, Acid/base imbalanceFollows Na+, Acid/base imbalance

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TYPES OF ACID-BASE TYPES OF ACID-BASE IMBALANCEIMBALANCE

• RESPIRATORYRESPIRATORY ACIDOSIS ACIDOSIS

• RESPIRATORY RESPIRATORY ALKALOSISALKALOSIS

• METABOLICMETABOLIC ACIDOSIS ACIDOSIS

• METABOLIC METABOLIC ALKALOSISALKALOSIS

Name reflects underlying cause, Name reflects underlying cause, compensationcompensation

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Blood Gases & Acid/Base Blood Gases & Acid/Base BalanceBalance

• Normal arterial blood pH: 7.35-7.45Normal arterial blood pH: 7.35-7.45

• Acidosis: pH < 7.35Acidosis: pH < 7.35

• Alkalosis: pH > 7.45Alkalosis: pH > 7.45

• Respiratory Acidosis/AlkalosisRespiratory Acidosis/Alkalosis– Reflected in PaCO2: [35-45 mg Hg]Reflected in PaCO2: [35-45 mg Hg]

• resp rate from any cause blows off CO2resp rate from any cause blows off CO2

• Resp rate from any cause conserves CO2Resp rate from any cause conserves CO2

– Compensation is via kidneysCompensation is via kidneys

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Blood Gas & Acid/Base Blood Gas & Acid/Base BalanceBalance• Metabolic Acidosis/AlkalosisMetabolic Acidosis/Alkalosis

– Base Excess: amount of buffer [Hgb & Base Excess: amount of buffer [Hgb & bicarb]bicarb]

– Norm: -2mEq/L - +2mEq/L [HCO3- 22-26]Norm: -2mEq/L - +2mEq/L [HCO3- 22-26]– Alkalosis: BE > +2mEq/L or Bicarb>26 Alkalosis: BE > +2mEq/L or Bicarb>26

•[[from acid loss/ vomiting, gastric suctionfrom acid loss/ vomiting, gastric suction]]

– Acidosis: BE< -2 mEq/L or Bicarb < 22 Acidosis: BE< -2 mEq/L or Bicarb < 22 •[[e.g. from diarrhea, renal diseasee.g. from diarrhea, renal disease]]

– CompensationCompensation is via Respiratory system is via Respiratory system

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Nursing Process: Nursing Process: AssessmentAssessment• History, risk factorsHistory, risk factors::

– surgery, burns, renal, respiratory or cardiac surgery, burns, renal, respiratory or cardiac disease, GI distress, diet/fluid intakedisease, GI distress, diet/fluid intake

• Age Age – Infants - ↑ percentage of body is H2OInfants - ↑ percentage of body is H2O

• Infants/children have low tolerance for changeInfants/children have low tolerance for change

– Adolescents – sports, recreational drugsAdolescents – sports, recreational drugs– Older adults - ↓ kidney fx, ↓ compensationOlder adults - ↓ kidney fx, ↓ compensation

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Nursing Process: Nursing Process: AssessmentAssessment • EnvironmentalEnvironmental factors [e.g. sweating] factors [e.g. sweating]

• DietDiet: intake, change: intake, change

• LifestyleLifestyle: etoh, smoking: etoh, smoking

• MedicationsMedications: diuretics, steroids, opioids, : diuretics, steroids, opioids, ABX, GI meds, NSAIDS, ecstasyABX, GI meds, NSAIDS, ecstasy

• AssessmentAssessment::– s/sx of hydration [skin, mm, pulses] wt s/sx of hydration [skin, mm, pulses] wt

[rapid change = fluid], I&O, Labs[rapid change = fluid], I&O, Labs

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Nursing ProcessNursing Process: Diagnosis: Diagnosis• [Risk for] Deficient Fluid Volume[Risk for] Deficient Fluid Volume r/t vomiting r/t vomiting

AEB skin tenting, ↑ HR, dry mucous membranesAEB skin tenting, ↑ HR, dry mucous membranes

• Decreased cardiac outputDecreased cardiac output r/t low circulating r/t low circulating blood volume AEB weak pulses, orthostatic hypotensionblood volume AEB weak pulses, orthostatic hypotension

• Excess fluid volumeExcess fluid volume r/t excess intake of free water r/t excess intake of free water AEB bounding pulse, 2 lb wt gain in 24 hrsAEB bounding pulse, 2 lb wt gain in 24 hrs

• Impaired gas exchangeImpaired gas exchange r/t high respiratory rate r/t high respiratory rate 22° to acid-base imbalance AEB dizziness, confusion° to acid-base imbalance AEB dizziness, confusion

• Disturbed sensory perceptionDisturbed sensory perception [tactile] r/t [tactile] r/t altered calcium level 2° to pancreatitis AEB numbness in altered calcium level 2° to pancreatitis AEB numbness in hands & feet, serum Ca 3.8mEq/Lhands & feet, serum Ca 3.8mEq/L

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Nursing ProcessNursing Process: Goals: Goals

• Pt will demonstrate moist mucous Pt will demonstrate moist mucous membranes, balanced I&O and membranes, balanced I&O and stable weight within 48 hoursstable weight within 48 hours

• Pt will demonstrate serum electrolyte Pt will demonstrate serum electrolyte levels WNL within 24levels WNL within 24 hourshours

• Pt will limit dietary fluids to 600 ml Pt will limit dietary fluids to 600 ml [per cardiac diet orders] daily this [per cardiac diet orders] daily this weekweek

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Nursing ProcessNursing Process: : InterventionsInterventions• Strict I&O [document!] dailyStrict I&O [document!] daily• Offer 240ml of fluid of choice 1 hr after Offer 240ml of fluid of choice 1 hr after

mealsmeals• Monitor daily serum electrolytes, wtMonitor daily serum electrolytes, wt• Assist pt to select foods within Assist pt to select foods within

prescribed diet plan [e.g. fluid-prescribed diet plan [e.g. fluid-restricted]restricted]

• Administer IV solutions per ordersAdminister IV solutions per orders• Teach client/ family to recognize Teach client/ family to recognize

acidosis s/sx this a.m.acidosis s/sx this a.m.04/22/2304/22/23 5858


Nursing ProcessNursing Process: Evaluation: Evaluation

• Goal met/not met/partially met?Goal met/not met/partially met?

• How do you know?How do you know?

• Continue or revise planContinue or revise plan

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Questions?Questions?

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FLUIDS, ELECTROLYTES, WATER AND ACID – BASE BALANCE

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