Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Sem 1 Theory > Unit 4 - Acid-Base Balance > Flashcards

Unit 4 - Acid-Base Balance Flashcards

1
Q

What is the definition of acid-base balance?

A

Acid-base balance is defined as the process of regulating the pH, bicarbonate concentration, and partial pressure of carbon dioxide of bodily fluids. It is a dynamic interplay between three processes: acid production or intake, acid buffering, and acid excretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is acid?

A

a substance that releases Hydrogen ions (H+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a base?

A

a substance that takes up H+. Bicarbonate (HCO3-) is the most important base in the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is acid production?

A

the generation of acid through cellular metabolism. Our cells continuously generate two kinds of acid during metabolism: carbonic acid (H2CO3) and metabolic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the process of acid intake?

A

involves entry into the body of acids or substances that the body convers to acids (acid precursors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is acid buffering?

A

the process by which bodily fluids resist large changes in pH when acids or bases are added or removed. Body fluids normally have buffers, which are pairs of chemicals that take up H+ or release it to keep pH in the normal range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the process of acid excretion?

A

the removal of acid from the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the range of optimal acid-base balance?

A

7.35 to 7.45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is respiratory acidosis?

A

Respiratory acidosis is excess carbonic acid (measured as elevated PaCO2) in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is respiratory alkalosis?

A

Respiratory alkalosis is too little carbonic acid (measured as decreased PaCO2) in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is metabolic acidosis?

A

Metabolic acidosis is excess metabolic acid (measured as decreased HCO3-) in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is metabolic alkalosis?

A

Metabolic alkalosis is too little acid (measured as increased HCO3-) in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the scope of acid-base balance?

A

It is a continuum from acidotic (lower than normal pH) on one end to optimal balance in the middle and alkaloid (higher than normal pH) on the other end.

There is optimal acid-base balance and two categories of acid-base imbalance: acidosis and alkalosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the normal physiological process of acid-base balance?

A

When optimal acid-base balance is occurring, the buffers are not overwhelmed by the amount of acid that is generated and acid excretion keeps pace with acid production.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is created through acid production?

A

Carbonic acid (H₂CO₃) and metabolic acid (HA).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a metabolic acid?

A

Any acid that is produced by cellular metabolism except carbonic acid.

Examples of metabolic acid are citric acid, pyretic acid, and lactic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the purpose of acid buffering?

A

Buffers help keep the pH of the blood and other body fluids in the normal range despite the metabolic acid continuously produced by the cells. A buffer is a pair of chemicals (a weak acid and its base) that are in equilibrium in a solution. These two parts of a buffer system must be present in a specific ratio to keep the pH normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the most important buffer in the extracellular fluid?

A

The most important buffer in the extracellular fluid is the bicarbonate buffer system, which consists of carbonic acid (the weak acid) and bicarbonate (its base). When the bicarbonate-to-carbonic acid ration is 20 : 1, the blood pH is in the normal range. If the ratio changes, significantly, the blood pH becomes abnormal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the purpose of acid excretion?

A

The two types of acid produced by cellular metabolism differ in that carbonic acid is converted to gases and metabolic acid is not. The lungs excrete the gaseous form of carbonic acid, and the kidneys excrete metabolic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How is carbonic acid excreted?

A

The lungs serve as the excretory organ for carbonic acid. The lungs are not able to excrete metabolic acid because it cannot be converted into a gaseous form. Changes in rate and depth alter the amount of carbonic acid that is excreted. The chemoreceptors influence respiratory rate and depth in response to blood levels of CO2 and H+ and, in some situations, oxygen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does hyperventilation influence carbonic acid excretion?

A

Increased rate and depth of respiration excreted more carbonic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does hypoventilation influence carbonic acid excretion?

A

Decreased rate and depth of respiration excretes less carbonic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When the amount of CO2 increases in the blood, the chemoreceptors…

A

When the amount of CO2 increases in the blood, the chemoreceptors increase the respiratory rate and depth, which excretes more CO2 and H2O (carbonic acid) and helps restore the CO2 level to its normal range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If the blood has too little CO2, the chemoreceptors…

A

If the blood has too little CO2, the chemoreceptors decrease the respiratory rate and depth, which enables CO2 level to rise to its normal range because the cells constantly are producing it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does compensation refer to?

A

moving the pH toward its normal range while making other blood values abnormal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does correction refer to?

A

fixing the problem (excess or insufficient CO₂ in the blood) and returning the blood values to their normal range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

If too much metabolic acid accumulates, the chemoreceptors trigger…

A

 If too much metabolic acid accumulates, the chemoreceptors trigger hyperventilation. This does not correct the problem because the lungs cannot excrete metabolic acid, but hyperventilation removes more carbonic acid from the body, thus making the blood less acidic. The result is too little carbonic acid, which helps balance the too much metabolic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

If too little metabolic acid is present, the chemoreceptors cause…

A

If too little metabolic acid is present, the chemoreceptors cause hypoventilation. This compensatory process moves the pH down toward its normal range by allowing too much carbonic acid to help balance too little metabolic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How is metabolic acid excreted?

A

metabolic acid is excreted through the kidneys

30
Q

How do the kidneys respond to excess carbonic acid?

A

If too much carbonic acid accumulates, the kidneys cannot excrete it, but they can excrete more metabolic acid than usual. This renal response to decreased pH compensates for the problem by causing too little metabolic acid in the blood, which somewhat balances the too much carbonic acid, the renal compensatory response is less secretion of H+ and less generation of NH3. The resulting increase of metabolic acid is an attempt to balance the lack of carbonic acid, normalizing the pH by making other blood values abnormal.

31
Q

What are the physiological differences of acid-balance in infants?

A

Infants have several pertinent physiological differences. An infant has a much greater percentage of total body weight attributed to fluid (75%) compared to an adult (60%), more intracellular fluid and an immature renal system that is inefficient in excreting a sudden acid load. An infant’s metabolic rate is higher and the fluid exchange ratio is far greater than those of an adults. These differences place infants at higher risk for metabolic acidosis, as well as fluid and electrolyte imbalances, compared to older children and adults.

32
Q

What are the physiological differences of acid-balance in older adults?

A

A normal physiological change associated with gaining is reduced size and function of the kidneys, which play a critical role in maintaining acid-base balance. Despite this age-related gradual loss of nephrons, the kidneys of the older adult typically are able to manage their role in fluid, electrolyte, and acid-base balance under normal circumstances. However, older adults have reduced renal reserve. They are less able to excrete a large acid load renally, and their ability to compensate may be less effective. This makes older adults more susceptible to acid-base disturbances, as well as to fluid and electrolyte imbalances.

33
Q

What is acidosis?

A

In a situation of too much acid, the buffers have been overwhelmed and body fluids have too much acid. Acid excretion is not able to keep up with acid production or intake. Conditions of too much acid are called acidosis and are given an additional descriptor that explains whether there is too much carbonic acid or too much metabolic acid.

34
Q

What is alkalosis?

A

In situations of too little acid, the buffers also are not able to keep the pH in the normal range and body fluids do not have enough acid. Too much of the base HCO3- has been added to the buffer system or acid excretion is greater than acid production. Conditions of too little acid are called alkalosis- either respiratory alkalosis when there is too little carbonic acid or metabolic alkalosis when there is too little metabolic acid.

35
Q

What is the stimulus, respiratory response, and renal response of respiratory acidosis?

A
36
Q

What is the stimulus, respiratory response, and renal response of respiratory alkalosis?

A
37
Q

What is the stimulus, respiratory response, and renal response of metabolic acidosis?

A
38
Q

What is the stimulus, respiratory response, and renal response of metabolic alkalosis?

A
39
Q

If the pH falls abnormally low from too much acid…

A

If the pH falls abnormally low from too much acid, both the lungs and the kidneys will excrete more acid, even though only one of the organs will be excreting the type of acid that is excessive. The other organ is compensating. Depending on the time course and severity of the problem, the disruption may be uncompensated, partially compensated, or fully compensated.

40
Q

If a problem with the respiratory system disrupts acid-base balance and the lungs are unable to correct it…

A

If a problem with the respiratory system disrupts acid-base balance and the lungs are unable to correct it, renal compensatory mechanisms adjust the pH toward normal. It takes several days for renal compensatory mechanisms adjust the pH toward normal. It takes several days for renal compensatory mechanisms to become clinically significant; therefore a short-lived respiratory acidosis or alkalosis will not become compensated

41
Q

If a problem with the kidneys disrupts acid-base balance and the kidneys are unable to correct it…

A

if a problem with the kidneys disrupts acid-base balance and the kidneys are unable to correct it, respiratory compensation begins a few minutes after the pH becomes abnormal, so it is common to have some degree of compensation for a disruption of acid-base balance that involves too much or too little metabolic acid. When the disruption is severe, it will be only partially compensated.

42
Q

What populations are at risk for acid-base imbalance?

A

All individuals, regardless of race, culture, age, or socioeconomic status, need optimal acid-base balance for physiological function.

From a population perspective, those at greatest risk for acid-base disturbances are the very young and the very old.

43
Q

Why are pre-term infants at high risk for acid-base imbalance?

A

Preterm infants are at great risk for acid-base disturbances due to immature lungs, kidneys, thermoregulation, and metabolic processes; the degree of risk is largely related to the weight and gestational age at the time of birth

44
Q

Why are term infants at high risk for acid-base imbalance?

A

Term infants also have greater risk than adults due to immature kidneys, elevated metabolic rate, and large fluid exchange ratio.

45
Q

Why are older adults at high risk for acid-base imbalance?

A

Older adults have decreased renal reserve due to a normal gradual loss of nephrons, making their ability to correct and to compensate for imbalances less effective. Thus, they are more susceptible to acid-base disturbances than younger adults.

46
Q

What are the individual risk factors for acid-base imbalance?

A

Acid-base imbalances usually occur as a consequences of another underlying condition. Those at greatest risk for acid-base imbalances are individuals who have at least one of the following risk factors:
o Excessive production or intake of metabolic acid
o Altered acid buffering due to loss or gain of bicarbonate
o Altered acid excretion
o Abnormal shift of H+ into cells

47
Q

What are common underlying conditions that lead to respiratory acidosis?

A
48
Q

What are common underlying conditions that lead to respiratory alkalosis?

A
49
Q

What are common underlying conditions that lead to metabolic alkalosis?

A
50
Q

What are risk factors for excessive production or intake of metabolic acid?

A

Risk factors for excessive production or intake of metabolic acid includes the risk factors for ketoacidosis or poisoning with acids or substances the body converts to acid. The cells cannot stop producing metabolic acid, so decreased acid production is not a risk factor.

51
Q

What are risk factors for altered acid buffering due to loss or gain of bicarbonate?

A

Risk factors for altered acid buffering include prolonged diarrhea and excessive sodium bicarbonate intake in people of any age. These conditions place them at risk for metabolic acidosis or metabolic alkalosis

52
Q

What are risk factors for altered acid excretion?

A

 Risk factors for altered acid excretion include respiratory or other conditions that interfere with the ability to excrete enough carbonic acid, conditions causing hyperventilation that excretes too much carbonic acid, kidneys that are unable to excrete enough metabolic acid, and situations in which the kidneys or repeated episodes of vomiting remove too much metabolic acid from the body.

53
Q

What are risk factors of abnormal shift of H+ into cells?

A

 Factors that shift substantial numbers of H+ into cells can cause too little acid to be in the blood. The most common example in this category of risk factors is hypokalemia (abnormally low plasma potassium concentration). When hypokalemia is present, some potassium ion (K+) leave cells and H+ enter cells to maintain a balance of electrical charge. The result is too little metabolic acid in the blood, known as metabolic alkalosis. The primary risk factor for abnormal shift of H+ into cells is hypokalemia

54
Q

What is included in the history for acid-base imbalance?

A

Acid-base imbalances cause nonspecific signs such as decreased LOC that have many possible causes. It is critical that nurses consider presenting symptoms in the context of other current health conditions. The history focuses on the respiratory, renal, or other conditions that could cause the acid-base problem. The standard questions for any history apply. Other areas to explore in the history include the following:
o Recent history of vomiting or diarrhea (repeated vomiting causes metabolic alkalosis; prolonged diarrhea causes metabolic acidosis)
o Use of heartburn or indigestion medications (a few days of baking soda/sodium bicarbonate ingestion can cause metabolic alkalosis)
o Recent attempts to lose weight and methods employed (high-fat, low-carbohydrate diet or fasting predispose to starvation ketoacidosis)
o Use of medications, dietary supplements, illicit drugs, and alcohol

55
Q

What are the examination findings for acid-base imbalance?

A

Unless the acid-base imbalance is severe, specific signs and symptoms of disrupted acid-base balance often are overshadowed by the clinical manifestations of the underlying cause.

56
Q

What are the common clinical findings and blood gas findings of respiratory acidosis?

A

Common clinical findings: headache, decreased LOC, hypoventilation (cause of problem), cardiac dysrhythmias; if severe, hypotension

Blood gas findings: pH decreased (or low normal if fully compensated); PaCO₂ increased; HCO₃ increased from compensation

57
Q

What are the common clinical findings and blood gas findings of metabolic acidosis?

A

Common clinical findings: hyperventilation (compensatory mechanism), abdominal pain, nausea and vomiting, cardiac dysrhythmias

Blood gas findings: pH decreased (or low if fully compensated); PaCO₂ decreased from compensation; HCO₃ decreased

58
Q

What are the common clinical findings and blood gas findings of respiratory alkalosis?

A

Common clinical findings: excitation and belligerence, lightheadedness, unusual behaviors; followed by decreased LOC if severe, perioral and digital paresthesias carpopedial spasm, tetany; diaphoresis, hyperventilation (cause of problem), cardiac dysrhythmias

Blood gas findings: pH increased; PaCO₂ decreased; HCO₃ decreased if compensation

59
Q

What are the common clinical findings and blood gas findings of metabolic alkalosis?

A

Common clinical findings: excitation followed by decreased LOC if severe; perioral and digital paresthesias, carpopedal spasm; hypoventilation (compensatory mechanism); signs of volume depletion and hypokalemia if present

Blood gas findings: pH increased; PaCO₂ increased from compensation; HCO₃ increased

60
Q

What are the diagnostic tests for acid-base balance?

A

Arterial blood gas measurement is the definitive diagnostic test for acid-base balance. In some settings, venous blood gas values are used instead of arterial. This section provides the conceptual basis for interpreting arterial blood gas results related to acid-base status. The commonly used values are pH, PaCO₂ , HCO₃- concentration, and base excess.

61
Q

Normal pH range

A

The pH of the blood has a normal range of 7.35 to 7.45 in adults, which is slightly alkaline. The normal range is lower in in neonates and infants.

In clinical settings, the term acidemia is used when the pH declines below the lower limit of normal. The term alkalemia denotes a blood pH that is above the normal range.

62
Q

Normal PaCO₂ range

A

The partial pressure of CO2 in the arterial blood. It indicates how well the lungs are excreting carbonic acid (CO2 and H2O). The normal range of PaCO2 is 35 to 45 mm Hg for adults (lower in infants).

Increased PaCO2 level indicates CO2 accumulation in the blood (too much carbonic acid) caused by primary or compensatory hypoventilation; decreased PaCO2 level indicates excessive CO2 excretion (too little carbonic acid) caused by primary or compensatory hyperventilation.

63
Q

Normal HCO₃ concentration

A

The serum HCO₃- concentration indicated how well the kidneys are excreting metabolic acid. The normal adult range is 22 to 26 mEq/L; the range is lower in infants.

Increased HCO₃- concentration indicates that the blood has too little metabolic acid; decreased HCO₃- concentration indicates that the blood has too much metabolic acid.

64
Q

Normal base excess range

A

Base excess, which normally ranges from -2 to +2 mmol/L, is an indicator of how well the buffers are managing metabolic acid. Values less than -2 mmol/L (negative base excess) indicate too much metabolic acid; values greater than +2 mmol/L indicate too little metabolic acid. When people develop metabolic acidosis, clinicians may calculate other values, such as the anion gap and the Stewart strong ion difference, to assist in diagnosing the specific cause

65
Q

Primary prevention for acid-base balance

A

The primary prevention for a disrupted acid-base balance focuses on prevention of the major risk-factors previously discussed rather than on prevention of the disrupted acid-base itself. Many of the primary prevention strategies aimed at specific disease processes and behaviors detrimental to health in general also help to prevent disrupted acid-base balance that can arise from these risk factors.

Ex. discouraging smoking, diabetes management, weight maintenance, hand hygiene, etc.

66
Q

Secondary prevention for acid-base balance

A

Screening measures to detect disrupted acid-base balance are not performed in the general population

67
Q

How does prevention of respiratory disease help to prevent acid-base imbalance?

A

prevention of respiratory diseases helps to prevent risk factors for accumulating too much carbonic acid

68
Q

How does teaching and management of diabetes and weight loss help to prevent acid-base imbalance?

A

Careful diabetes teaching and management help prevent ketoacidosis as well as other complications of diabetes. Teaching people how to lose weight safely without totally eliminating carbohydrates can help to prevent starvation ketoacidosis as well as to achieve weight management goals.

69
Q

How does poison prevention efforts prevent acid-base imbalance?

A

Poison prevention efforts can help prevent excessive ingestion of acids or acid precursors.

70
Q

How does hand washing prevent acid-base imbalance?

A

Instruction regarding hand hygiene and safe food storage helps prevent diarrhea and vomiting—two common risk factors for disrupted acid-base balance

71
Q

Exemplars of Respiratory Acidosis

A

bacterial pneumonia, acute asthma, type B COPD

Sem 1 Theory (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions