ABG Flashcards
What is the pH of arterial blood versus venous blood?
Arterial blood pH ranges from 7.35 -7.45
Venous blood pH ranges from 7.31-7.41
What is the acid-base balance?
The acid-base balance is a result of processes that carefully regulate hydrogen ion production and elimination. Body fluid pH is a measure of the bodies fluids free hydrogen ion level
True or false
Because it is calculated in negative logarithm units, the value of pH is inversely related to the level of free hydrogen ions. In other words, the lower the pH value of the fluid, the higher the level of free ions in that fluid
True
Keeping the pH of the blood within normal range is important because changes from the normal interfere with many functions such as…
- Changing the shape and reducing the function of hormones and enzymes
- Changing the distribution of other electrolytes, causing fluid and electrolyte imbalances
- Changing excitable membranes, making the heart, nerves, muscle, G.I. track either less or more active than normal
- Decreasing effectiveness of drugs
What are acids?
Acids are substances that release hydrogen ions when dissolved in water. And acid in solution increases the amount of free hydrogen ions in that solution
What are bases?
The base is a substance that binds free hydrogen ions in solution. Thus bases are hydrogen acceptors that lower the amount of free hydrogen ions in solution.
What are buffers?
Buffers are critically keeping body fluid pH a normal levels because they can react in two ways, either as an acid or the base. Buffers always try to bring the fluid as close as possible to the normal body fluid pH of 7.35 to 7.45
What is the most common base and common acid in the human body?
The most common base is bicarbonate
The most common acid is carbonic acid
What does that carbonic anhydrase equation show?
This equation, driven by the enzyme carbonic anhydrase, shows how hydrogen ion levels and carbon dioxide levels are DIRECTLY related to one another, so that any increase in one causes an equal increase in the other
True or false
Carbonic acid is not stable, and the body needs to keep a 1:20 ratio of carbonic acid to bicarbonate
True
True or false
The carbon dioxide content of the fluid is directly related to the amount of hydrogen ions in the fluid
True
What is the normal O2 level in an adult?
80-100 mm Hg
What is the normal CO2 level in an adult?
Arterial: 35-45 mm Hg
Venous: 40-50 mm Hg
What is the normal level of bicarbonate in an adult?
Arterial: 21-28 mm Hg
Venous: 24-29 mm Hg
What is the CO2 and pH correlation of the body?
Whenever the CO2 level changes, the pH changes to the same degree, in the opposite direction. So when the CO2 level of a liquid increases, pH drops indicating more free hydrogen ions or more acidic. On the other hand, when the CO2 level the liquid decreases, the pH arises, indicated you were free hydrogen ions or more alkaline.
What is the main buffer of the ECF?
Bicarbonate, It is kept at a level 20 times greater than that of carbonic acid
What is one factor that determines blood pH?
How much CO2 is produced by body cells during metabolism versus how rapidly that CO2 is removed by breathing
What does protein breakdown form?
Sulfuric acid
How is lactic acid formed?
Incomplete breakdown of glucose, which occurs whenever cells metabolize under anaerobic conditions, forms lactic acid
What is the first, second and third line of defense against changes in the amount of free hydrogen ions?
Buffers are the first line of defense
The respiratory system is the second line of defense
The kidneys are the third line of defense
What are buffers composed of?
Buffers are composed of chemicals are proteins
What are chemical buffers?
Chemical buffers are paired mixtures, usually a week base and an acid salt. The two most common chemical buffers are bicarbonate and phosphate.
What are protein buffers?
Protein buffers are the most common buffers. extracellular buffers are albumin and globulins. A major cell protein buffer is hemoglobin
True or false
Hemoglobin buffers hydrogen ions directly and also buffers acids formed during the production of carbon dioxide
True
True or false
Because CO2 is converted into hydrogen ions through the carbonic anhydrase reaction, the CO2 level is directly related to the hydrogen ion level
True
What actions do the kidneys take when the blood pH is not normal?
- The kidneys move bicarbonate
- Form acids
- Form ammonia
What is the first kidney pH control action?
Kidney movement of bicarbonate is the first kidney pH control action. It occurs in the kidney tubule in two ways, 1. kidney movement of bicarbonate produced elsewhere in the body and 2. kidney movement of bicarbonate produced in the kidneys.
What is the second kidney pH control action?
The formation of acids. It occurs through the phosphate buffer and system inside of cells of the kidney tubule.
What is the third kidney pH control action?
Formation of ammonium is the third kidney pH control action. Ammonia which is converted during a normal protein breakdown, is converted into ammonium. The ammonia is first secreted into the urine, working combine with excess hydrogen ions to form ammonium. The ammonium traps the hydrogen ions in that allows them to be excreted in the urine. The result of the loss of hydrogen ions in an increase in blood PH
True or false
A pH below 6.9 or above 7.8 is usually fatal
True
How did the kidneys compensate when the blood pH is acidic?
To oppose this process, the kidney excretes more hydrogen ions increases the reabsorption of bicarbonate back into the blood
A patient with COPD has just developed respiratory distress. Vital signs are; pulse ox 88% on 2 L nasal cannula oxygen; dyspnea at rest; respirations 32 per min. The patient reports shortness of breath. Which statements apply to this clinical situation?
- Interference in alveolar capillary diffusion results in carbon dioxide retention
- The nurse should instruct the patient to use pursed lip breathing
- Interference in alveolar capillary diffusion results in acidemia
In the case of the previous question, what is the priority order of actions the nurse takes to manage this patient?
- Call the respiratory therapist
- Delegate the monitoring of vital signs to unlicensed personnel
- Page the physician immediately
- Document the incident in the patients chart
A patient with bilateral lower lobe pneumonia is diagnosed to have respiratory acidosis based on arterial blood gas results. What is this patients likely cause of respiratory acidosis?
Under elimination of carbon dioxide from the lungs
A patient is admitted to the hospital for diabetic ketoacidosis. What may likely occur with this patient?
- Metabolic acidosis
- Excessive oxidation of fatty acids
- Overproduction of hydrogen ions
A patient who recently emigrated to the US from germany, but speaks fluent english, has been admitted to the ER with diabetic ketoacidosis. On intake assessment, the patient cannot recall the medications she takes. What actions does the nurse take?
- Instruct the patient to compare a hospital list of medications to her home medications when she is discharged home
- Ask the patient or SO about the patients typical 24 hour home meal plan
- Have a social worker assess if the patient has insurance or money to pay for medications
A patient who has pancreatitis with nausea and vomiting will likely have which related alterations in acid base balance?
- Metabolic acidosis
- Serum pH value that is directly related to the concentration of hydrogen ions
- Underproduction of bicarbonate
Which statements correctly apply to acid base balance in the body?
- Renal mechanisms are stronger in regulating acid base balance but slower to respond than respiratory mechanisms
- The immediate binding of excess hydrogen ions occurs primarily in the RBCs
- Acid base balance occurs through control of hydrogen ion production and elimination
An increase in the CO2 level causes the free hydrogen level to increase and the pH to decrease, or become more……
Acidic
The ratio between carbonic acid and bicarbonate should remain at……
1:20
In the healthy person, the kidneys control……levels and the lungs control…..levels
The kidneys control bicarbonate levels and the lungs control CO2 levels
Base accepts..
Base accepts hydrogen ions
Acid…
Acid donates the hydrogen ion
What is formed in the body as a result of metabolism?
Acid
What releases or binds hydrogen ions into/from a fluid
Buffers
Measure of the bodys free hydrogen ion level
pH
What is H2CO3?
An acid
What increases as the amount of base increases?
pH
Hemoglobin is a…
buffer
Chemoreceptors response to increase in CO2
Respiratory
Binding of hydrogen ions to phosphate ions to form H2PO4
Renal
Reabsorbs HCO3
Renal
Binds H with HCO3
Chemical
Binds H with hemoglobin
Protein
Response occurs within minutes
Respiratory
The early stage of incomplete breakdown of glucose occurs whenever cells metabolize under anaerobic conditions to form lactic acid. Based on this knowledge of pathophysiology, which conditions could cause the patient to develop acidosis?
- Sepsis
- Hypovolemic shock
- Hypoventilation
Which patient with the highest risk for acidosis must the nurse care for first?
Patient with COPD, pulse ox 88% on 2 L oxygen
A patients ABG results show an increase in pH. Which condition is most likely to contribute to this lab value?
Nasogastric suction
Which patient is most likely to have a decrease in bicarbonate?
Patient with pancreatitis
A patient has a new onset of shallow and slow respirations. While the patients body attempts to compensate, what happens to the patients pH level?
Decreases
A patient is at risk for acid base imbalance. Which lab value indicates that the patient is acidotic?
pH is 7.30
Which type of medication increases an older adult patients risk for acid base imbalance?
Diuretics
The nurse is giving discharge instructions about medication to an older, forgetful patient, and the daughter whom the patient lives with at home. What does the nurse do to facilitate medication compliance?
- Find out how the patient organizes his or her medications at home
- Included the daughter in the discharge instructions
- Have the social worker ask the patient about his or her ability to pay for medication
- Suggest that the patient use a weekly pill organizer and have the daughter supervise medication admin.
Diabetic ketoacidosis
Hydrogen ion production
Renal failure
Hydrogen ion elimination
and base production
Dehydration
Base production
Seizures
Hydrogen ion production
Pancreatic insufficiency
Base production
Diarrhea
Base elimination
Airway obstruction examples
- Asthma
2. Bronchiolitis
Inadequate chest expansion exampes
- Muscular dystrophy
- Ascites
- Flail chest
- Hemothorax
- Hyperkalemia
Respiratory depression examples
- Morphine infusion
2. Stroke
Altered alveolar capillary diffusion examples
- Pulmonary embolus
2. Pneumonia
Which medication usage could cause metabolic acidosis?
Aspirin overdose
Which nursing assessment finding indicates a worsening of respiratory acidosis?
Use of accessory respiratory muscles
Which patient is most likely to have respiratory acidosis?
Patient with multiple rib fractures
Which patient requires assessment related to inadequate chest expansion, which places the patient at risk for respiratory acidosis?
- Patient with emphysema
2. Severely obese patient on prolonged bedrest
The nurse reviews the ECG and cardiovascular status of a patient. Which findings are early changes associated with mild acidosis?
Increased heart rate and increased cardiac output
The nurse is assessing a patient with an acid base imbalance by using gordons functional health patterns. What primary areas are affected?
- Activity exercise
- Elimination
- Cognitive perceptual
The nurse is testing the muscle strength of a patient at risk for acid base imbalance. Which technique does the nurse use to test arm strength?
The patient flexes the arms against the chest, the nurse tries to pull the arms from the chest
The nurse assesses an acidotic patients lower extremities for strength has a part of the shift assessment. What finding is the nurse expect to see?
Bilateral weakness
The nurse observes tall peaked T waves on the ECG of a patient with metabolic acidosis. Before notifying the healthcare provider, the nurse also assesses the results of which lab test?
Serum potassium
.Kussmaul respirations are signs of…
Metabolic acidosis
Shallow, rapid respirations are signs of…
Respiratory acidosis
Warm, flushed skin is a sign of…
Metabolic acidosis
Skin pale to cyanotic is a sign of…
Respiratory acidosis
Elevated PaCO2 levels is a sign of..
Respiratory acidosis
Decreased bicarbonate is a sign of…
Metabolic acidosis
What plan of care for patients metabolic ketoacidosis?
- Monitor ABG levels for decreasing pH level
- Maintains patent IV access
- Administer fluids as prescribed
- Monitor determinants of tissue oxygen delivery, such as hemoglobins
- Monitor loss of bicarbonate through the G.I. tract such as diarrhea
What is the priority intervention for patient with diabetic ketoacidosis?
Administer insulin
Which statement made by the patient indicates that here she may have an alkaline condition?
I have tingling in my fingers and toes