E2: Acid-Base Balance

what is the normal range for neutral pH?

7.35 - 7.45

Whats considered Acidic pH?

below 7.35

whats considered alkaline pH?

above 7.45

Whats the normal range for partial pressure carbon dioxide? (PaCO2)

35-45 mmHg

what system regulates PaCO2?

Respiratory, lungs

whats the normal range for HCO3? (carbonic acid)

22 - 26(28) mEq/L

what system regulates HCO3?

renal system, kidneys

what is the normal range for partial pressure of oxygen? (paO2)

80-100 mmHg

what are the only two ways a acidotic state can exist?

too much PaCO2

too little HCO3

what are the only two ways a alkalotic state can exist?

too little PaCO2

too much HCO3

How long does it take for the respiratory response to occur?

1-3 minutes = Quick

what does the respiratory system asses?

amount of carbonic acid (CO2) in the blood

an increased amount of CO2 has what affect on blood and respiratory system?

decreased pH (more acidic)

respiratory system increases RR to get rid of extra CO2

a decreased amount of CO2 has what affect on blood and respiratory system?

increased pH (more alkaline)

respiratory system decreased RR, whats to keep CO2

how long does it take for the renal response to occur?

hours to days = slower

what does the renal system assess?

bicarbonate HCO3 by excreting it or retaining it

Decreased blood pH will cause the renal system to do what?

retain HCO3

Increased blood pH will cause the renal system to do what?

excrete HCO3

what body system changes can occur in a acidic state?

decrease in force of cardiac contraction = decrease in cardiac output

decreased vascular response to catecholamines

decrease medication effects

what body system changes occur in a alkalotic state?

decreased tissue oxygenation, notably to heart and brain

decreased neuro and MSK function

describe Respiratory Acidosis

accumulation of CO2 in the lungs

increase in CO2 in blood = acidic pH

what is the primary cause of respiratory acidosis

hypoventilation

(head injury, impaired respiratory muscle function, actolesis pneumonia, massive PE, rib fx)

what are the s/s for respiratory acidosis?

decreased RR

fatigue

dyspnea

tachycardia, arrythmias

headache

describe respiratory alkalosis

removing too much CO2 from the lungs

what is the primary cause of respiratory alkalosis?

Hyperventilation

(anxiety, fear, fever, sepsis, pregnancy, meds)

what are the s/s of respiratory alkalosis?

arrhythmia’s

palpitations

sweating

lightheadedness

numbness and tingling in fingers and toes

confusion

blurred vision

describe metabolic acidosis

hypoxic tissue beds in the body

base deficit in blood stream or too much acid in blood stream

what is the primary cause of metabolic acidosis

renal failure, diabetes, ketoacidosis, starvation, aspirin intoxication

what are s/s of metabolic acidosis

arrythmias

warm flushed skin

headache

confusion

lethargy

nausea and vomiting

kussmauls RR

describe metabolic alkalosis

excess base or loss of too much acid in the body

what primarily causes metabolic alkalosis?

too many anti-acids, protracted vomiting, gastric suction, diuretics

what are the s/s of metabolic alkalosis?

respiratory depression

dizziness

lethargy

seizures, comas

muscle weakness (including heart)

muscle twitching

cramps,

tetany

nausea and vomiting

PRACTICE: is HCO3 = 32 mEq/L within normal range ? does it indicate more alkaline or acidic pH?

no, high

indicates more alkaline

PRACTICE: is PaCO2 = 32 mmHg within normal range? does it indicate more alkaline or acidic pH?

no, low

indicates more alkaline

PRACTICE: is HCO3 = 19 mEq/L within normal range? does it indicate more alkaline or acidic pH?

no, low

indicates more acidic

PRACTICE: is PaCO2 = 56 mmHg within normal range? does it indicate more alkaline or acidic pH?

no, high

indicates more acidic

PRACTICE:

pH: 7.35

PaCO2: 39 mmHg

HCO3: 24 mEq/L

Name of condition?

Normal

Normal

Normal

N/A

PRACTICE:

pH: 7.30

PaCO2: 53 mmHg

HCO3: 23 mEq/L

Name of Condition?

Acidic

Acidic

Normal

Respiratory Acidosis

PRACTICE:

pH: 7.48

PaCO2: 32 mmHg

HCO3: 22 mEq/L

Name of Condition?

Alkaline

Alkaline

Normal

Respiratory Alkalosis

PRACTICE:

pH: 7.32

PaCO2: 39 mmHg

HCO3: 21 mEq/L

Name of Condition?

Acidic

Normal

Acidic

Metabolic Acidosis

PRACTICE:

pH: 7.52

PaCO2: 37 mmHg

HCO3: 32 mEq/L

Name of Condition?

Alkaline

Normal

Alkaline

Metabolic Alkalosis

what is the normal range for pH? What is the cutoff point?

7.35 - 7.45

7.40

If a acid-base balance is UNCOMPENSATED does it mean its inside or outside the normal range?

Outside!

If a acid-base balance is COMPENSATED does it mean its inside or outside the normal range?

Inside!

If pH is below 7.40, what does that mean?

Acidosis

If pH is above 7.40, what does that mean?

Alkalosis

PRACTICE COMP OR UNCOMP:

pH: 7.50

PaCO2: 37 mmHg

HCO3: 30 mEq/L

Name of Condition?

Alkaline

Normal

Alkaline

Uncompensated Metabolic Alkalosis

PRACTICE COMP OR UNCOMP:

pH: 7.49

PaCO2: 19 mmHg

HCO3: 21 mEq/L

Name of Condition?

Alkaline

Acidic

Alkaline

Uncompensated Respiratory Alkalosis

PRACTICE COMP OR UNCOMP:

pH: 7.37

PaCO2: 32 mmHg

HCO3: 20 mEq/L

Name of Condition?

Normal → Acidic

Alkaline

Acidic

Compensated Metabolic Acidosis

PRACTICE COMP OR UNCOMP:

pH: 7.39

PaCO2: 47 mmHg

HCO3: 50 mEq/L

Name of Condition?

Normal → Acidic

Acidic

Alkaline

Compensated Respiratory Acidosis

PRACTICE COMP OR UNCOMP:

pH: 7.44

PaCO2: 41 mmHg

HCO3: 29 mEq/L

Name of Condition?

Norma → Alkaline

Normal

Alkaline

Compensated Metabolic Alkalosis

What does Hypercapnia mean?

Too much CO2 in the blood stream

What does Hypocapnia mean?

Abnormally low levels of CO2 in blood stream

what does Hypoxia mean?

low levels of O2 in tissues

What does Hypoxemia mean?

low levels of O2 in the blood

what is the 4-5-6-7-8-9 rule?

estimation of PaO2 based on SpO2 measurement

PRACTICE: if SpO2 is 90%, what is PaO2?

60 mmHg

PRACTICE: if SpO2 is 80%, what is PaO2?

50 mmHg

PRACTICE: if SpO2 is 70%, what is PaO2?

40 mmHg

PRACTICE: if SpO2 is 60%, what is PaO2?

30 mmHg

what is the value for No Hypoxemia in PaO2 (mmHg) ( pressure of arterial oxygen)?

80-100 mmHg

O2 Sat: >95%

what is the value for mild hypoxemia in PaO2 (mmHg) (pressure of arterial oxygen)?

60-79 mmHg

O2 Sat: 90-94%

what is the value for moderate hypoxemia in PaCO2 (mmHg) (pressure of arterial oxygen)?

40-59 mmHg

O2 Sat: < 89%

at what O2 values is exercise contraindicated?

Moderate Hypoxemia

40-59 mmHg

O2 Sat: <89%