ABG Flashcards
What is normal pH?
7.35-7.45
What pH is considered perfect?
7.4
Acidic pH
< 7.35
Base/Alkalosis pH
> 7.45
PaCO2 normal
35-45
PaCO2 BASE/ALKALOSIS
< 35
PaCO2 Acidic
> 45
HCO3 normal
22-26
HCO3 Acidic
<22
HCP3 Alkalosis/Base
> 26
PaO2 normal
80-100
PaO2
- mild hypoxemia
70-79
PaO2
- moderate hypoxemia
60-69
PaO2
- severe hypoxemia
<60
SaO2 normal
> 95 %
What are the steps to Analyzing ABG?
1) Determine Acidosis or Alkalosis using pH level
2) Determine respiratory effect on the body using PaCO2
3) Determine metabolic effect on the body using HCO3
4) Determine compensation
5) Determine oxygenation
Homeostasis is the
acid/base balance
How do you determine compensation in an ABG?
Take the unused value and interpret if it is abnormal or in the normal range.
If the value is within the normal range
If the value is abnormal, then compensation is occuring
Partial compensation = abnormal pH
Full compensation = normal pH
DM ABG
Metabolic acidosis
esp. DKA (3Ps, Kussmaul’s breathing as compensation)
- give insulin drip and fluids
COPD ABG
respiratory acidosis
- pursed lip breathing to breath out CO2
Is acid/base balance a disease?
no it is never alone and is caused by something
When do you trust the SpO2 monitor due to its unreliability?
When observing the patient and the s/s or lack of s/s corroborate with each other
ABG is used to determine what
oxygenation status
acid-base balance (compensation)
ABG is used along with what to determine oxygenation?
pulse ox
What systems are used to help compensate acid/base imbalance?
Buffer system
Respiratory
Renal
Buffer system
if the other is out of balance the other system will respond by lowering or raising their molecules
Respiratory system on acid/base balance
lungs help breathe faster or slower based on what you need
Renal system on acid/base balance
take 2-3 days to help and get out the bad stuff
PaO2
partial oxygenation in the arterial blood
SaO2
tissue oxygenation perfusion
PaCO2
partial pressure of CO2 in the arterial line (ACID)
pH measures
H+ ion concentration
CO2 is the what component of our blood gas
acid
What is the fastest way of changing our pH?
CO2 - respiratory
12-24 hours
What do the lungs do to compensate for acidosis?
RR and depth will increase
- CO2 “blow off”
What do the lungs do to compensate for alkalosis?
RR and depth will decrease
- CO2 retained
The renal system is what component of our blood gas?
base
How long does the renal system take to respond to an imbalance?
hours to days (2-3 days)
Which system has the quickest response time to an acid/base imbalance?
Respiratory system
What do the kidneys do to compensate for acidosis?
H+ ions will be excreted and HCO3- will be retained
What do the kidneys do to compensate for alkalosis?
H+ ions will be retained and HCO3- will be excreted
ROME
Respiratory Opposite
Metabolic Equal
Respiratory Alkalosis
pH and PaCO2 LEVELS
pH high
CO2 low
Respiratory Acidosis
pH and PaCO2 LEVELS
pH low
CO2 high
Metabolic Acidosis
pH and HCO3 LEVELS
pH low
HCO3 low
Metabolic Alkalosis
pH and HCO3 LEVELS
pH high
HCO3 high
CO2 forms what when dissolved in the blood
carbonic acid
high CO2 lowers pH
CO2 level if hyperventilattion
<35 alkalosis
CO2 level if hypoventilation
> 45 acidosis
What causes respiratory acidosis?
Head trauma
over sedation
NM disorders
COPD
Pain from Rib fx
Respiratory arrest/problems (pneumonia - fluid in lungs alveoli sticky/ atelectasis/ ashtma)
What causes respiratory alkalosis?
Pregnancy and labor
pulmonary emboli
acute asthma
nervousness, anxiety, fear
high altitude
Hyperventilation and mechanical ventilation
Respiratory Acidosis S/S
hypoventilation - hypoxia
rapid, shallow RR
low BP with vasodilation
dyspnea
HA
Hyperkalemia
- dysrhythmias
drowsy, dizzy, disorientation
muscle weakness, hyperreflexia
What is happening in respiratory acidosis?
build up of CO2 in the blood due to shallow RR
Tx for Respiratory Acidosis causes
Asthma (AIMS)
- O2 6L if not helping then move on to simple mask 6L, then NRB 10L then mechanical ventilators)
TCDB and IS - tighten airway and get fluid off
elevated HOB
Sodium Bicarbonate
Tx the cause
Respiratory Alkalosis S/S
seizures
rapid, deep RR
hyperventilation
tachycardia
low/normal BP
hypokalemia
numb and tingling of extremities
lethargy and confusion
light headedness
N/V
Respiratory Alkalosis Tx
cause
- Anxiety: Benzos and Ativan
HCO3 acidosis level
<22
HCO3 alkalosis level
> 26
The “seesaw effect” refers to
Respiratory effect
The “elevator” effect refers to
Metabolic effects
Metabolic Acidosis causes
DKA , hypermetabolism
Renal insufficiency/failure
Incomplete metabolism of carbs (lactic acidosis)
Salicylate intoxication
Severe diarrhea, fistulas
Malnutrition, liver failure
High fat diet
Metabolic Alkalosis causes
excessive vomiting
ingestion of excess sodium bicarb
prolonged gastric lavage/ suctioning
administer of potent diuretics
Metabolic Acidosis S/S
HA
low BP
Hyperkalemia
muscle twitching
warm, flushed skin (vasodilation)
N/V
low muscle tone/reflexes
(confusion, increase drowsiness)
Kussmaul respirations (compensatory hyperventilation)
Tx for metabolic acidosis from DKA
insulin drips and fluid
check glucose every hour
O2
possible Bicarbonate
Metabolic alkalosis s/s
restlessness followed by lethargy
dysrhythmias (tachycardia)
compensatory hypoventilation
confusion (low LOC, dizzy, irritable)
N/V/D
tremors, muscle cramps, tingling of fingers and toes
hypokalemia
How can you prevent/tx of metabolic alkalosis
suction on INT
fluid/electrolyte imbalance
hemodialysis
A 55 year-old is recovering from an exploratory laparotomy in the PACU. The nurse notices the patient’s RR is 7/ minute, demonstrates shallow breathing and has no response to stimuli. The nurse assesses the ABC’s and obtains a STAT ABG.
pH = 7.15
PaCO2 = 68
HCO3 = 22 mEq/L
PaO2 = 68 mmHg
Uncompensated Respiratory Acidosis with Moderate Hypoxemia
A 79 year-old is admitted to the emergency room with nausea, vomiting and abdominal pain that has developed diarrhea after eating a 3 week old sandwich.
pH= 7.55
PaCO2 = 48
HCO3 = 47.2
PaO2 = 57.7
Partially Compensated Metabolic Alkalosis with Severe Hypoxemia
A 65 year-old is admitted to the emergency room with inability to urinate and admits to taking an unknown number of aspirin over the last 24-hour period because of a severe headache. Vital signs are: T=98.5, Pulse= 92, RR=30 and deep. Routine blood test and ABG reveals:
pH= 7.37
PaCO2= 30
HCO3 = 17
PaO2 = 80
Fully Compensated Metabolic Acidosis with Normal Oxygenation
Mrs. Puffer is a 35-year-old single mother. She reports to the ED in the early morning with shortness of breath. She has cyanosis of the lips. She has had a productive cough for 2 weeks. Her temperature is 102.2, blood pressure 110/76, heart rate 108, respirations 32, rapid and shallow. Breath sounds are diminished in both bases, with coarse rhonchi in the upper lobes. Chest X-ray indicates bilateral pneumonia.
ABG results are:
pH= 7.44
PaCO2= 28
HCO3= 21
PaO2= 54
What does the S/S and ABG show?
How can you tx this patient?
Respiratory Alkalosis
Fully compensated
Severe hypoxemia
- Tx pneumonia with TCDB, IS, O2, antibiotics, sodium bicarbonate, albuterol
Mr. Worried is a 52-year-old widower. He is retired and living alone. He enters the ED complaining of shortness of breath and tingling in fingers. His breathing is shallow and rapid. He denies diabetes; blood sugar is normal. There are no EKG changes. He has no significant respiratory or cardiac history. He takes several antianxiety medications. He says he has had anxiety attacks before. While being worked up for chest pain an ABG is done and results are:
pH= 7.48
PaCO2= 28
HCO3= 22
PaO2= 85
What does the S/S and ABG show?
How can you tx this patient?
Respiratory Acidosis
Fully compensated
Normal oxygenation
Anxiety attack - Ativan
You are the critical care nurse about to receive Mr. Sweet, a 24-year-old being admitted for DKA (diabetic ketoacidosis). In report you learn that his blood glucose on arrival was 780. He received 10 unites of regular insulin IV X2 doses in the ED.
ABG results are:
pH= 7.33
PaCO2= 25
HCO3=12
PaO2= 89
What does the S/S and ABG show?
How can you tx this patient?
Metabolic Acidosis
Partially compensated
Normal oxygenation
Mrs. Dobins was found pulseless and not breathing this morning. After a couple minutes of CPR she has a pulse of 50 bpm and starts breathing on her own; but remains unresponsive with no gag reflex. A blood gas is obtained and the results include:
pH = 6.89
CO2 = 70
p02 = 42
HC03 = 13
Pa02 = 50%
What does the S/S and ABG show?
How can you tx this patient?
Respiratory Acidosis
Partially compensated
Severe hypoxemia
You find Mr. Simmons to be in respiratory distress. He was admitted with shortness of breath and productive cough X1 week and has been diagnosed with pneumonia. He has a history of Type-I diabetes mellitus and his blood glucose is 583 and he is now febrile. His ABG shows:
pH = 7.00
C02 = 59
p02 = 86
HC03 = 14
Sa02 = 91%
What does the S/S and ABG show?
How can you tx this patient?
Respiratory Acidosis
Partially compensated
Normal oxygenation
