2. ACID – BASE BALANCE HOMEOSTASIS Relative [ ] of hydrogen ions
pH – potential hydrogen
Normal pH: – 7.45
<7.35 is acidosis
>7.45 is alkalosis

3. Deviation of 0.4 in either direction can be fatal

4. ACIDOSIS
Metabolic Acidosis
Excessive blood acidity or loss of bicarbonate
Causes
ingestion of something that is or can be metabolized to an acid
such as…..

5. Wood alcohol
Antifreeze
Large doses of ASA
Abnormal metabolism
Advanced stages of shock
Poorly controlled IDDM
Normal levels of acid if kidneys aren’t functioning normally

6. Symptoms
Mild metabolic acidosis may have no sx.
Usually experiences
nausea
vomiting
fatigue
Breathing becomes deeper and slightly faster
As acidosis worsens:

7. Extremely weak and drowsy
May feel confused
Increasingly nauseated
Eventually b/p can fall leading to shock, coma, or death
Treatment:
Depends primarily on the cause
insulin
removing toxic substances

8. RESPIRATORY ACIDOSIS
Build up of CO2 in the blood from poor lung function or slow breathing
Blood becomes acidic -> pH drops  respiratory center in the brain stimulates faster and deeper breathing
Develops when…….

9. Develops when the lungs do not expel CO2 adequately….such as
Emphysema
Chronic bronchitis
Severe pneumonia
Pulmonary edema
Asthma

10. Diseases of the nerves or muscles of the chest
If overly sedated from narcotics and strong sleeping medications that slow respirations
Symptoms:

11. First symptom may be headache and drowsiness
Drowsiness may progress to stupor or coma
ABGs
Treatment…..

12. Aims at improving function of the lungs
i.e. drugs to improve breathing
If acidosis is mild, IV fluid may be all that is needed
If severe; HCO3- (provides only temporary relief and may cause harm by overloading the body with Na+ and H2O

13. Treatment
Slow down rate
Pain relief
Other facts to ponder………….

14. J:\Class Presentations\BA Acid Base Disturbances.doc

15. Life essential functions like K+ and Na+ channels are inactivated by acidosis
A habitually acid pH can directly cause immediate weight gain
Fasting and dieting are known acid producing conditions
One way the body compensates is to deposit excess acid into tissues and joints

16. Acid producing foods create excess mucus, which congests the system and block oxygen from entering

17. ALKALOSIS Overabundance of bicarbonate in the blood
Loss of acid from the blood

18. Respiratory Alkalosis
Low levels of CO2 in the blood that results from rapid or deep breathing
Hyperventilation
anxiety
cirrhosis
low levels of oxygen in the blood
fever
ASA overdose

19. METABOLIC ACIDOSIS
Body looses too much acids
Gain too much base
stomach acid is lost during periods of prolonged vomiting
excessive loss of Na+ or K+ affects the kidney’s ability to control the blood’s acid-base balance
loss of K+ - use of diuretics or corticosteroids

20. Corticosteroids
Steroid hormones
Synthesized from cholesterol
Involved in stress response, immune response, regulation of inflammation, carbohydrate metabolism, protein catabolises blood electrolyte level and behavior

21. Catabolism: breaks down molecules into smaller units and releases energy
Alkalosis may cause:
Irritability
Muscle twitching
Muscle cramps
If severe, prolonged contraction and spasms of muscle (tetnaory)

22. Treatment
Metabolic
Replacing H2O, Na+, and K+ while treating underlying cause
Next: …………..

23. FLUIDS AND ELECTROLYTYES
Water
60% total body weight
Distributed into various compartments, separated by cell membranes
Largest compartment is intracellular environment
ICF
All the fluid found inside body cells
75% of all water is found within this compartment

24. Extracellular compartment
2 divisions
Intravascular fluid
Outside the cells and within the circulatory system. Essentially the same as the blood plasma

25. Interstitial fluid
Outside the cell membranes, not within the circulatory system
TBW
Infants – 75-80%
Infants have less fat. Fat does not absorb water. Less fat, more water

26. Water is essential for high rates of metabolism necessary to promote growth
With age
Loss of muscle mass inc. % of fat
Body’s decreasing ability to regulate fluid levels lower TBW to 45-55%
Elderly and very young are at high risk for dehydration and disorders related to to electrolyte imbalances

27. ELECTROLYTES
Dissociate in electronically charged particles when placed into water
ions
Cations + charge
Anions - charge

28. Cations
Na+
Most prevalent in extracellular fluid
Plays major role in distribution of water
Important in the transmission of nervous impulses

29. K+
Intracellular fluid
Transmission of electrical impulses
Ca++
Major role in muscle contraction
Nervous impulse transmission

30. Mg++
Necessary for several biochemical processes (over 300)
Prevents over excitability of muscles
½ found in bone
½ found predominantly inside cells of tissues and organs
Helps maintain normal nerve and muscle function

31. Regulates heart rhythm
Supports healthy immune system
Keeps bones strong
Helps regulate blood sugar levels
Promotes normal blood pressure
Known to be involved in protein synthesis and metabolism

32. ANIONS
Cl-
Plays a major role in fluid balance and renal function
HCO3-
Principal buffer

33. Phosphate
HPO4-
Body energy stores
Closely associated with Mg++ in renal function
Acts as a buffer primarily in the intracellular space

34. OSMOSIS AND DIFFUSION
Isotonic
When solutions on opposite sides of a semipermiable membrane are equal in [ ]
> on one side – hypertonic
< on one side – hypotonic
Difference in [ ] – osmotic gradient

35. Homeostasis
The tendency to keep the balance of water
electrolytes are = on both sides of the membrane.
Diffusion
Movement from an area of higher [ ] to lower [ ] and does not require energy

36. Osmosis
The passage of any solvent usually water through a membrane
Active Transport
Movement of a substance across the cell membrane against the osmotic gradient or toward the side that already has more of the substance; requires an expenditure of energy

37. Facilitated diffusion
Diffusion of a substance such as glucose that requires the assistance of a helper or carrier protein

38. FLUIDS
COLLOIDS
Contain large proteins
Cannot pass through a capillary membrane
Remains in the circulatory system
Increases volume of blood and fluid contained within the blood vessels

39. CRYSTALLOID
Contain electrolytes and water
Tonicity: number of particles per unit volume
Isotonic
Tonicity equal to blood plasma
Will not cause a significant fluid or electrolyte shift

40. HYPERTONIC
Higher solute [ ] that the cells
Causes fluid shift out of intracellular compartment into extracellualar compartment

41. HYPOTONIC
Lower solute [ ] than the cells
Movement extracellular  intracellular

42. ABGs
Determine pH but also to differentiate respiratory / metabolic acidosis / alkalosis
Norms pH
PaCO
PaO2 greater than 80
HCO

43. PaCO2
Amount of CO2 dissolved in arterial blood
PaO2 amount of oxygen dissolved in arterial blood
HCO3 amount of bicarbonate

44. Interpretation
(R)espirtory (O)pposite, (M)etabolic (E)qual
If the pH is opposite the PaCO2 (high or low) then it’s respiratory if the pH is equal to the HCO3, it is metabolic

45. Problem #1
pH 7.30
PaCO2 50
HCO3 26
PaO2 60
Acidosis or Alkalosis?
Metabolic or Respiratory?
Answer………

46. Respiratory Acidosis
Why?
pH is high indicating Acidosis
pH is low; PaCO2 is high {opposite} indicating this is respiratory
Problem #2

47. pH 7.50
PaCO2 43
HCO3 45
PaO2 80
Acidosis or Alkalosis?
Metabolic or Respiratory?
Answer………

48. Metabolic Alkalosis
Why?
pH is high indicating alkalosis
pH high; HCO3- high {equal}
Indicating this is metabolic
METABOLIC ACIDOSIS