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Acid-Base Balance MechanismsBuffer - prevents major changes in ECF by releasing or accepting H ionsBuffer mechanism: first line (takes seconds)1. combine with very strong acids or bases to convert them into weaker acids or bases2. Bicarbonate Buffer System- most important- uses HCO3 & carbonic acid/H2CO3 - (20:1)- closely linked with respiratory & renal mechanisms3. Phosphate Buffer System- more important in intracellular fluids, where concentration is higher- similar to bicarbonate buffer system, only uses phosphate4. Protein Buffer System- hemoglobin, a protein buffer, promotes movement of chloride across RBC membrane in exchange for HCO3

Respiratory mechanism: 2nd line (takes minutes)1. increased respirations liberates more CO2 = increase pH2. decreased respirations conserve more CO2 = decrease pHcarbonic acid (H2CO3) = CO2 + water

Renal mechanism: 3rd line (takes hours-days)1. kidneys secrete H ions & reabsorb bicarbonate ions = increase blood pH2. kidneys form ammonia that combines with H ions to form ammonium ions, which are excreted in the urine in exchange for sodium ions

Review: Acid-Base ImbalancepH – 7.35-7.45pCO2 – measurement of the CO2 pressure that is beingexerted on the plasma- 35-45mmHgPaO2- amount of pressure exerted by O2 on the plasma- 80-100mmHgSaO2- percent of hemoglobin saturated with O2Base excess – amount of HCO3 available in the ECF- -3 to +3

Interpretation Arterial Blood GasesIf acidosis the pH is downIf alkalosis the pH is upThe respiratory function indicator is the PCO2The metabolic function indicator is the HCO3Step 1Look at the pHIs it up or down?If it is up - it reflects alkalosisIf it is down - it reflects acidosisStep 2Look at the PCO2Is it up or down?If it reflects an opposite response as the pH,then you know that the condition is a respiratory imbalanceIf it does not reflect an opposite response as the pH - move to step IIIStep 3Look at the HCO3Does the HCO3 reflect a correspondingresponse with the pHIf it does then the condition is a metabolic imbalance

A. FLUID VOLUME DEFICIT or HYPOVOLEMIADefinition: This is the loss of extra cellular fluid volume that exceeds the intake of fluid. The loss of water and electrolyte is in equal proportion. It canbe called in various terms- vascular, cellular or intracellular dehydration. But the preferred term is hypovolemia.Dehydration refers to loss of WATER alone, with increased solutes concentration and sodium concentration.

Pathophysiology of Fluid Volume Deficit

Etiologic conditions include:a. Vomitingb. Diarrheac. Prolonged GI suctioningd. Increased sweatinge. Inability to gain access to fluidsf. Inadequate fluid intakeg. Massive third spacing

Risk factors are the following:a. Diabetes Insipidusb. Adrenal insufficiencyc. Osmotic diuresisd. Hemorrhagee. Comaf. Third-spacing conditions like ascites, pancreatitis and burns

ASSESSMENT:Physical examinationWeight loss, tented skin turgor, dry mucus membraneHypotensionTachycardiaCool skin, acute weight lossFlat neck veins

Decreased CVPSubjective cuesThirstNausea, anorexiaMuscle weakness and crampsChange in mental state

Laboratory findings1. Elevated BUN due to depletion of fluids or decreased renal perfusion2. Hemoconcentration3. Possible Electrolyte imbalances: Hypokalemia, Hyperkalemia, Hyponatremia, hypernatremia4. Urine specific gravity is increased (concentrated urine) above 1.020NURSING MANAGEMENT1. Assess the ongoing status of the patient by doing an accurate input and output monitoring2. Monitor daily weights. Approximate weight loss 1 kilogram = 1liter!3. Monitor Vital signs, skin and tongue turgor, urinary concentration, mental function and peripheral circulation4. Prevent Fluid Volume Deficit from occurring by identifying risk patients and implement fluid replacement therapy as needed promptly5. Correct fluid Volume Deficit by offering fluids orally if tolerated, anti-emetics if with vomiting, and foods with adequate electrolytes6. Maintain skin integrity7. Provide frequent oral care8. Teach patient to change position slowly to avoid sudden postural hypotension

B. FLUID VOLUME EXCESS: HYPERVOLEMIADefinition : Refers to the isotonic expansion of the ECF caused by the abnormal retention of water and sodiumThere is excessive retention of water and electrolytes in equal proportion. Serum sodium concentration remains NORMALPathophysiology of Fluid Volume ExcessEtiologic conditions and Risks factorsa. Congestive heart failureb. Renal failurec. Excessive fluid intaked. Impaired ability to excrete fluid as in renal disease

e. Cirrhosis of the liverf. Consumption of excessive table saltsg. Administration of excessive IVFh. Abnormal fluid retention

PATHOPHYSIOLOGYExcessive fluid --- expansion of blood volume ----- edema,increased neck vein distention, tachycardia, hypertension.

The Nursing Process in Fluid Volume Excess

ASSESSMENTPhysical ExaminationIncreased weight gainIncreased urine outputMoist crackles in the lungsIncreased CVPDistended neck veins

WheezingDependent edema

Subjective cue/sShortness of breathChange in mental state

Laboratory findings1. BUN and Creatinine levels are LOW because of dilution2. Urine sodium and osmolality decreased (urine becomes diluted)3. CXR may show pulmonary congestion

IMPLEMENTATIONASSIST IN MEDICAL INTERVENTION1. Administer diuretics as prescribed2. Assist in hemodialysis3. Provide dietary restriction of sodium and water

NURSING MANAGEMENT1. Continually assess the patient‟s condition by measuring intake and output, daily weight monitoring, edema assessment and breath sounds2. Prevent Fluid Volume Excess by adhering to diet prescription of low salt- foods.3. Detect and Control Fluid Volume Excess by closely monitoring IVF therapy, administering medications, providing rest periods, placing in semi fowler‟s position for lung expansion and providing frequent skin care for the edema.4. Teach patient about edema, ascites, and fluid therapy. Advise elevation of the extremities, restriction of fluids, necessity of paracentesis, dialysis and diuretic therapy.5. Instruct patient to avoid over-the-counter medications without first checking with the health care provider because they may contain sodium

Name:_________________________________________ Year/Level:______________ Date:____________

QUIZ

Instruction: Read Carefully. Each question in this examination lists 4 possible answers. Choose the One Best answer for each and ENCIRCLE the letter of choice.

Any forms of erasures are not allowed!

1. What is the normal range of carbon dioxide (CO2) in arterial blood?

A.35-45B.22-26

C.7.35-7.45D.not listed

2. What is the normal range of bicarbonate ion (HCO3-) in arterial blood?

A.35-45B.22-26


3. What is the normal range of pH in the body?

A.35-45B.22-26


4. If HCO3- caused the acidosis or the alkalosis, it is what?

A.metabolicB.Respiratory

C.combinedD.none

5. If the CO2 and the HCO3- caused the imbalance, it is what?

A.metabolicB.respiratory

C.combinedD.none

6. If the CO2 caused the acidosis or alkalosis, it is what?

A.metabolicB.respiratory

C.combinedD.none

7. When there is an abnormal pH and change in one blood parameter. It is

A.uncompensatedB.partially compensated

C.fully compensatedD.corrected

8. When all 3 values--- pH, HCO3-, CO2 are abnormal. It is



9. When pH is normal, both HCO3 and CO2 are abnormal. It is



10. When all parameters of pH, HCO3-, and CO2 are normal. It is



11. pH 7.31, CO2 50mmHg, HCO3- 22mEq/L

A.Respiratory acidosis, UncompensatedB.Respiratory alkalosis, Partially compensated

C.Metabolic acidosis, Fully compensatedD.Metabolic alkalosis, Uncompensated

12. pH 7.46, CO2 32mmHg, HCO3- 23mEq/L

A.Respiratory acidosis, Partially compensatedB.Combined, Uncompensated

C.Metabolic alkalosis, UncompensateddD.Respiratory alkalosis, Uncompensated

13. pH 7.30, CO2 46 mmHg, HCO3 16 mEq/L

A.Respiratory alkalosis, Uncompensated B.Combined, Partially compensated

C.Respiratory acidosis, Partially compensated D.Metabolic acidosis, Partially compensated14. pH 7.31, CO2 44 mmHg, HCO3 20 mEq/L

A.Metabolic alkalosis, Fully compensatedB.Metabolic acidosis, Uncompensated

C.Respiratory alkalosis, partially compensatedD.Respiratory acidosis, Uncompensated


A.metabolic alkalosis, partially compensatedB.respiratory acidosis, uncompensated

C.metabolic acidosis, fully compensatedD.respiratory alkalosis, partially compensated


A.metabolic alkalosis, partially compensatedB.respiratory acidosis, uncompensated

C.combined, partially compensatedD.metabolic acidosis, uncompensated

17. Ben has anxiety attack. His ABGs results show he is in respiratory alkalosis. He has just had a car accident. What is your next nursing intervention?

A.Have him breathe into paper bagB.Give him O2

C.Check his temperatureD.Ask him if he is alright

18. A client with pneumonia presents with the following arterial blood gases: pH of 7.28, PaCO2 of 74, HCO3 of 28 mEq/L, and PO2 of 45, which of the following is the most appropriate nursing intervention?

A.Administer a sedativeB.Place client in left lateral position

C.Place client in high-Fowler's positionD.Assist the client to breathe into a paper bag

19. A client with COPD feels short of breath after walking to the bathroom on 2 liters of oxygen nasal cannula. The morning's ABGs were pH of 7.36, PaCO2 of 62, HCO3 of 35 mEq/L, O2 at 88% on 2 liters. Which of the following should be the nurse's first intervention?

A.Call the physician and report the change in client's conditionB.Turn the client's O2 up to 4 liters nasal cannulaC.Encourage the client to sit down and to take deep breaths

D.Encourage the client to rest and to use pursed-lip breathing technique

20. A client who had a recent surgery has been vomiting and becomes dizzy while standing up to go to the bathroom. After assisting the client back to bed, the nurse notes that the blood pressure is 55/30 and the pulse is 140. The nurse hangs which of the following IV fluids to correct this condition?

A.D5.45 NS at 50 ml/hrB.0.9 NS at an open rate

C.D5W at 125 ml/hrD.0.45 NS at open rate

21. A client with renal failure enters the emergency room after skipping three dialysis treatments to visit family out of town. Which set of ABGs would indicate to the nurse that the client is in a state of metabolic acidosis?

A.pH of 7.43, PCO2 of 36, HCO3 of 26B.pH of 7.41, PCO2 of 49, HCO3 of 30

C.pH of 7.33, PCO2 of 35, HCO3 of 17D.pH of 7.25, PCO2 of 56, HCO3 of 28

22. A client with a small bowel obstruction has had an NG tube connected to low intermittent suction for two days. The nurse should monitor for clinical manifestations of which acid-base disorder?

A.Respiratory alkalosisB.Respiratory acidosis

C.Metabolic alkalosisD.Metabolic acidosis

23. A client who suffers from an anxiety disorder is very upset, has a respiratory rate of 32, and is complaining of lightheadedness and tingling in the fingers. ABG values are pH of 7.48, PaCO2 of 29, HCO3 of 24, and O2 is at 93% on room air. The nurse performs which of the following as a priority nursing intervention?

A.Monitor intake and outputB.Encourage client to increase activityC.Institute deep breathing exercises every hourD.Provide reassurance to the client and administer sedatives

41. The nurse writes the nursing problem of "fluid volume excess" (FVE). Which intervention should be included in the plan of care?

A.Change the IV fluid from 0.9% NS to D5W.B.Restrict the client's sodium in the diet.C.Monitor blood glucose levels.D.Prepare the client for hemodialysis.

42. The nurse reviews the laboratory report of a patient with fluid volume deficit. Which of the following laboratory findings will support this condition?

a. WBC count of 9,000b. Creatinine of 1 mg/dl

c. Sodium of 140 mEq/Ld. Hematocrit of 58%

43. Of the following blood gas values, the one the nurse would expect to see in the client with acute renal failure is

a. pH 7.49, HCO3 24, PaCO2 46b. pH 7.49, HCO3 14, PaCO2 30

c. pH 7.26, HCO3 24, PaCO2 46d. pH 7.26, HCO3 14, PaCO2 30

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