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Mark Klimek Lecture Notes
LECTURE 1: Acid Base Balance & Ventilator
Interpreting blood gases
(remember the rules of the B’s)
• If the pH and the bicarb are both in the same direction then it’s metaBolic
(Bicarb Both Bolic), if they are in different directions then it is respiratory
• If bicarb is normal and the pH is low or high then its respiratory
• You will be given 8 values for arterial blood gas, always first look at the pH
and the bicarb first
• You get acidosis and alkalosis from the pH
LABS: ABG’s
The normal pH is 7.35-7.45
The normal bicarb is 22-26 (the bicarb years where you make all the decisions
[22-26 years old], or 2+2+2=6)
The normal CO2 is 35-45 (same as pH)
Signs and Symptoms with ABG’s
• As the pH goes up so does my patient
o If the pH goes up, every system in your body gets more
irritable/hyperexcitable
• As the pH goes down so does my patient
o If the pH goes down, systems in your body shut down
• Except for potassium- When pH goes down, potassium goes up
• If the pH goes up (alkalosis): you will find irritability, hyperreflexia (3&4),
tachypnea, tachycardia, borborygmi (increased bowel sounds), seizure (need
suctioning at the bed side because they can seize and aspirate)
• If pH goes down (acidosis): hyporeflexia, bradycardia, lethargy, obtunded,
paralytic ileus, coma, respiratory arrest (need bag-mask ventilation bag at
bedside for respiratory arrest), +1 reflexes
• MACkussmal- compensatory and respiratory pattern for only acid base
disorder: MAC- Metabolic ACidosis
, 2
Respiratory Acidosis multiple choice example: What would you see with a
patient who is in respiratory acidosis?
a. +1 reflex,
b. diarrhea,
c. adynamic ileus (no movement),
d. spasm,
e. urinary retention,
f. paraxysmol atrial tachycardia,
g. second degree lovitz, type 2 heart block (impulse is being slowed),
h. hypokalemia
LAB: REFLEXES
0&1-hyporeflexia
2-normal
3&4- hyperreflexia
EXAMPLE: (In general what do pain meds do?
ANSWER: They sedate you, they are CNS depressants: lethargy, lucidity, reflexes at
+1, hyporeflexia, obtundent
Causes of Acid Base Imbalance
• Don’t get signs and symptoms mixed up with causation!!!
• What causes something is the opposite of what the signs and symptoms are
o EXAMPLE: diarrhea will cause a metabolic acidosis but once you get
acidotic, it will shut your bowels down and you will get a paralytic ileus.
• The first question you should ask yourself if the scenario involves a lung
problem.
o Is it a respiratory problem? BUT remember it can still be respiratory
acidosis/alkalosis…
• Next question you ask yourself…
o is the client overventilating or underventilating?
o If the patient is overventilating pick alkalosis
o If they are underventilating pick acidosis
• If the client is overventilating.. it has an attachment to the word- alkalosis
(because they are both OVER)… ventilating OVER becomes respiratory
ALKALOSIS
, 3
• If the client is undeventilating.. it has an attachment to the word- acidosis
(because they are both UNDER)- ventilating UNDER becomes respiratory
ACIDOSIS
Examples:
1) A woman is overzealously using her breathing techniques during labor, what
acid base disorder will she exhibit? Overventilation
o Respiratory Alkalosis
2) A child is near drowning, what acid base disorder would it be?
Underventilating
o Respiratory Acidosis
3) Your patient has emphysema, what acid base disorder would it be?
Underventilating
o Respiratory Acidosis
Ventilating does not mean respiratory rate.. respiratory rate is irrelevant-
ventilation has to do with gas exchange!!
Examples:
1) Patient has pneumonia in 4 lobes of the lung, breathing at 50/min and their
SO2 is at 78 on 8 liters per max
o Explanation: Breathing really fast while still having a low O2 level
means that the patient is still underventilating because respiratory
rate has nothing to do with it. Everyone pays so much attention to
rate when they should be paying closer attention to the SO2.
o If your SO2 is good and you are breathing slow, you are fine but if
your SO2 is low and you’re breathing fast, you are actually
underventilating. A lot of times the respiratory rate compensates-
pay attention to SO2!!!
2) Patient is on a PCA pump, what acid base imbalance would tell you they need
to come off that thing?
o A PCA pump depresses respirations. So, patients need to come off
of it as soon as possible because if they were getting too much it
would make their respiratory rate go really down which would
, 4
make the patient underventilate so the answer would be
respiratory acidosis.
o So respiratory acidosis would tell you that you need to come off
the PCA pump.
What if its not lung?
It would be Metabolic.
Only one scenario that you will answer metabolic alkalosis: if the patient has
prolonged gastric vomiting or suctioning
pick metabolic alkalosis.. Why?
o Pt is losing acid... pt will become basic
Otherwise everything else that is not lung or the above, pick metabolic
acidosis
Ex.
1) Patient had GI surgery and has had an NG tube to low intermittent gone post
suctioning for 3 days, what acid base disorder would he most likely exhibit?
o Metabolic alkalosis
2) Patient has hyper emesis gravidarum , what acid base disorder are they going
to exhibit
o Metabolic alkalosis
3) Continuation: Pt is going to be dehydrated- what acid base disorder would
they have?
o Metabolic acidosis
4) Pt has acute renal failure, what acid base disorder would this be?
o Metabolic acidosis- its not lung or vomiting or suctioning so it has to
be metabolic acidosis
5) A pt with infantile diarrhea would have what acid base disorder?
o Metabolic acidosis
6) A pt with third degree burns over 60 percent of the body?
Mark Klimek Lecture Notes
LECTURE 1: Acid Base Balance & Ventilator
Interpreting blood gases
(remember the rules of the B’s)
• If the pH and the bicarb are both in the same direction then it’s metaBolic
(Bicarb Both Bolic), if they are in different directions then it is respiratory
• If bicarb is normal and the pH is low or high then its respiratory
• You will be given 8 values for arterial blood gas, always first look at the pH
and the bicarb first
• You get acidosis and alkalosis from the pH
LABS: ABG’s
The normal pH is 7.35-7.45
The normal bicarb is 22-26 (the bicarb years where you make all the decisions
[22-26 years old], or 2+2+2=6)
The normal CO2 is 35-45 (same as pH)
Signs and Symptoms with ABG’s
• As the pH goes up so does my patient
o If the pH goes up, every system in your body gets more
irritable/hyperexcitable
• As the pH goes down so does my patient
o If the pH goes down, systems in your body shut down
• Except for potassium- When pH goes down, potassium goes up
• If the pH goes up (alkalosis): you will find irritability, hyperreflexia (3&4),
tachypnea, tachycardia, borborygmi (increased bowel sounds), seizure (need
suctioning at the bed side because they can seize and aspirate)
• If pH goes down (acidosis): hyporeflexia, bradycardia, lethargy, obtunded,
paralytic ileus, coma, respiratory arrest (need bag-mask ventilation bag at
bedside for respiratory arrest), +1 reflexes
• MACkussmal- compensatory and respiratory pattern for only acid base
disorder: MAC- Metabolic ACidosis
, 2
Respiratory Acidosis multiple choice example: What would you see with a
patient who is in respiratory acidosis?
a. +1 reflex,
b. diarrhea,
c. adynamic ileus (no movement),
d. spasm,
e. urinary retention,
f. paraxysmol atrial tachycardia,
g. second degree lovitz, type 2 heart block (impulse is being slowed),
h. hypokalemia
LAB: REFLEXES
0&1-hyporeflexia
2-normal
3&4- hyperreflexia
EXAMPLE: (In general what do pain meds do?
ANSWER: They sedate you, they are CNS depressants: lethargy, lucidity, reflexes at
+1, hyporeflexia, obtundent
Causes of Acid Base Imbalance
• Don’t get signs and symptoms mixed up with causation!!!
• What causes something is the opposite of what the signs and symptoms are
o EXAMPLE: diarrhea will cause a metabolic acidosis but once you get
acidotic, it will shut your bowels down and you will get a paralytic ileus.
• The first question you should ask yourself if the scenario involves a lung
problem.
o Is it a respiratory problem? BUT remember it can still be respiratory
acidosis/alkalosis…
• Next question you ask yourself…
o is the client overventilating or underventilating?
o If the patient is overventilating pick alkalosis
o If they are underventilating pick acidosis
• If the client is overventilating.. it has an attachment to the word- alkalosis
(because they are both OVER)… ventilating OVER becomes respiratory
ALKALOSIS
, 3
• If the client is undeventilating.. it has an attachment to the word- acidosis
(because they are both UNDER)- ventilating UNDER becomes respiratory
ACIDOSIS
Examples:
1) A woman is overzealously using her breathing techniques during labor, what
acid base disorder will she exhibit? Overventilation
o Respiratory Alkalosis
2) A child is near drowning, what acid base disorder would it be?
Underventilating
o Respiratory Acidosis
3) Your patient has emphysema, what acid base disorder would it be?
Underventilating
o Respiratory Acidosis
Ventilating does not mean respiratory rate.. respiratory rate is irrelevant-
ventilation has to do with gas exchange!!
Examples:
1) Patient has pneumonia in 4 lobes of the lung, breathing at 50/min and their
SO2 is at 78 on 8 liters per max
o Explanation: Breathing really fast while still having a low O2 level
means that the patient is still underventilating because respiratory
rate has nothing to do with it. Everyone pays so much attention to
rate when they should be paying closer attention to the SO2.
o If your SO2 is good and you are breathing slow, you are fine but if
your SO2 is low and you’re breathing fast, you are actually
underventilating. A lot of times the respiratory rate compensates-
pay attention to SO2!!!
2) Patient is on a PCA pump, what acid base imbalance would tell you they need
to come off that thing?
o A PCA pump depresses respirations. So, patients need to come off
of it as soon as possible because if they were getting too much it
would make their respiratory rate go really down which would
, 4
make the patient underventilate so the answer would be
respiratory acidosis.
o So respiratory acidosis would tell you that you need to come off
the PCA pump.
What if its not lung?
It would be Metabolic.
Only one scenario that you will answer metabolic alkalosis: if the patient has
prolonged gastric vomiting or suctioning
pick metabolic alkalosis.. Why?
o Pt is losing acid... pt will become basic
Otherwise everything else that is not lung or the above, pick metabolic
acidosis
Ex.
1) Patient had GI surgery and has had an NG tube to low intermittent gone post
suctioning for 3 days, what acid base disorder would he most likely exhibit?
o Metabolic alkalosis
2) Patient has hyper emesis gravidarum , what acid base disorder are they going
to exhibit
o Metabolic alkalosis
3) Continuation: Pt is going to be dehydrated- what acid base disorder would
they have?
o Metabolic acidosis
4) Pt has acute renal failure, what acid base disorder would this be?
o Metabolic acidosis- its not lung or vomiting or suctioning so it has to
be metabolic acidosis
5) A pt with infantile diarrhea would have what acid base disorder?
o Metabolic acidosis
6) A pt with third degree burns over 60 percent of the body?
