Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Regulation of Acid-Base BalanceSlide 26Slide 27Acid-Base RegulatorsSlide 29Slide 30Slide 31Slide 32Slide 33AcidosisAcid-Base BalanceBreakdown of ABGsABGsSlide 38Slide 39Slide 40Slide 41Slide 42Slide 43Acid-Base ImbalancesRespiratory AcidosisRespiratory Acidosis CausesSlide 47Respiratory AcidosisRespiratory AlkalosisSlide 50Slide 51Metabolic AcidosisSlide 53Metabolic AlkalosisSlide 55QuestionSlide 57Slide 58Slide 59Slide 60Let’s reviewRegulation of Acid-Base Balance•Buffering systems neutralize acids & bases & include lungs & renals•Buffer—substance or a group of substances that can absorb or release H+ to correct an acid-base imbalance •Arterial pH indirect measurement of H+ ionRegulation of Acid-Base Balance•pH reflection of balance between CO2 (lungs) & HCO3- (renal)•Acidosis–Increased amount of H+ ions–Normal pH 7.35-7.45–pH = 7 is neutral–pH < 7 is acid–pH > 7 is alkalineRegulation of Acid-Base BalanceAB balance exists when the rate at which the body produces acid or bases = the rate at which the acids or bases are excretedNormal hydrogen ion level is necessary to maintain cell membrane integrity & speed of cellular enzymatic actionsAcid-Base Regulators•Chemical regulation–Largest chemical buffer in ECF is carbonic acid/bicarb buffer system–First buffer system to react–Reacts in seconds–Lungs control excretion of carbon dioxideAcid-Base Regulators•Kidneys control excretion of hydrogen & bicarbonate ions•ECF becomes more acidic pH decreases•ECF receives more base substances, pH risesAcid-Base Regulators•Biological Regulation–Occurs after chemical buffering–Occurs hydrogen ions are absorbed or released by cells–Hydrogen ion + charged & must be exchanged with another + charged ion—frequently K+•Conditions that produce excess acidH+ ion enter cellpotassium ion leaves cellenters ECFelevated K+ levelsAcid-Base Regulators•Biological buffer–Hemoglobin-oxyhemoglobin system–CO2 diffuses to RBCforms carbonic aciddissociates to H+ & HCO3+ ionsH+ ions attach to hemoglobinHCO3+ available for buffering •Chloride shift in RBCs–Bld oxygenated in lungs, bicarb diffuses into cellchloride travels from hemoglobin to plasma to maintain electrical neutralityAcid-Base Regulators•Physiological regulation–Lungs & kidneys–If diseased is no longer effective for regulation–Lungs adapt rapidly to imbalance–Increased H+ & CO2 ions stimulate respirationMetabolic acidosisresp increasegreater amt CO2 exhaleddecreased acidic levelAcid-Base Regulators•Physiological Regulation–Kidneys take a few hrs to several days to regulate acid-base balance–Inc or dec HCO3+ production–Certain amino acids in renal tubules change to ammonia NH3- & excreted by kidneysAcidosisAcid-Base Balance•Acid-base balance is regulated by the body’s ability to maintain arterial pH 7.35-7.45•Checked by ABGs•Deviation from normal value indicates experiencing an acid-base imbalanceBreakdown of ABGs•pH –Measures H+ ions concentration in body fluids–Slight change can be life threatening–Acidic—increase in H+ ions–Alkaline—decrease in H+ ionsABGsPaCO2Partial pressure of carbon dioxide in arterial bldReflection of depth of pulmonary ventilationNormal 35-45 mm Hg**Hyperventilation PaCO2 < 35 mm HgCarbon dioxide is exhaled & amt decABGs•**hypoventilation–PaCO2 is > 45 mm Hg–Less carbon dioxide is exhaled–Increasing concentration of carbon dioxideABGsPaO2Parital pressure of O2 in arterial bldNormal 80-100 mm HgN0 primary role in A-B regulation when normallPaO2 < 60 causes anaerobic metabolism—produces lactic acid—metabolic acidosisABGs•Oxygen Saturation–When hemoglobin is saturated with O2–Normall 95-99%–Changes in temp,PaCO2 & pH affect oxygenABGs•Base Excess–Amt of blood buffer–Normal +/- 2 mEq/L–High value—alkalosis•Citrate excess from rapid blood transfusions•IV HCO3 infusion DKA\•Ingestion large amt bicarb solutions (antacids)ABGs•Base excess–Low value—acidosis•Lg amts of bicarb ion excretion•ie: diarrhea–ABGs•Bicarbonate–Major renal component–Kidneys excrete & retain to maintain normal balance–Principal buffer ECF–Normal 22-26 mEq/L–Metabolic acidosis < 22 mEq/L–Metabolic alkalosis > 26 mEq/LAcid-Base Imbalances •Either respiratory or metabolic, depend on their underlying cause•Corrects AB imbalances through process known as compensationRespiratory AcidosispH < 7.35PaCO2 >45 mm HgPaO2 < 80 mm HgBicarb level normal if uncompensatedBicarb level > 26 mEq/L if compensatedHypoventilationCSF & brain cells become acidicneurological changes hypoxemiafurther neurological impairmentHyperkalemia & hypercalcemia can occurKidneys hold to bicarb & release hydrogen ions UA—may take 24 hrsRespiratory Acidosis Causes•Hypoventilation resulting primary respiratory problems–Chest wall injury–Respiratory failure–Cystic fibrosis–Pneumonia –Atelectasis (obstruction of small airways often caused by mucus)•Hypoventilation resulting from factors other than resp system–Obesity–Head injury–Drug overdose (OD) with resp depressant–Paralysis of resp muscles caused by neurological alterationsRespiratory AcidosisS/SConvulsionComaMuscular twitchingConfusionDizzinessLethargy HAWarm flushed skinVentricular dysrhythmiaRespiratory Alkalosis•pH >7.45•PaCO2 <35 mm Hg•PaO2 normal•HCO3 nl if short-lived or uncompensated•HCO3 <22 mm Hg if compensated•Begins outside resp system ie: anxiety, panic attack OR within resp system ie: initial phase of asthma attack•Body does not usually compensate because pH returns to nl before kidneys can respondRespiratory AlkalosisCausesSalicylate overdoesAnxietyHypermetabolic states ie: fever, exerciseCNS disorders ie: head injury, infectionsAsthmaPneumoniaInappropriate vent settingsS/SConfusionDizzinessConvulsionsComaTachypneaNumbness/tingling of extremitiesdysrhythmiasMetabolic AcidosisHigh acid content of bldLoss of HCO3pH <7.35PaCO2 normal if uncompensated<35 mm Hg if compensatedPaO2 normal or increasedHCO3 < 22 mEq/LO2 Sat normalMetabolic Alkalosis•pH