ABGs Flashcards
Normal pH
7.35-7.45
Normal PaCO2
35-45
- resp parameter
Normal HCO3
24-29
- metabolic parameter
- calc on the ABG OR on a chem panel as a serum CO2
Primary event
What causes the A/B imbalance
- hypovent, hypervent, vom
Primary disorder
What results from the primary event
- resp acidosis, met acidosis, etc
Metabolic imbalance
Problem of bicarb and kidneys
- chx in H+ or bicarb ions
Arterial blood gas labs
- pH (7.35-7.45)
- PaCO2 (partial pressure of CO2 in artery)
- HCO3 (calculated value)
Venous blood gas values
- pH (7.31-7.41)
- PvCO2 (partial pressure of CO2 in vein)–41-51
- HCO3 (calculated value)
Basic metabolic panel (BMP) aka chem panel labs
Serum CO2 = HCO3 level (24-29)
Respiratory imbalance
- H2CO3 changes secondary to resp alterations (lungs)
- resp problem in nature
- inc/dec in CO2
- change in ventilation
ROME
Respiratory Opposite, Metabolic Equal
Metabolic alkalosis
- too much bicarb or not enough carbonic acid
- pH inc, PaCO2 neutral, HCO3 inc
- excess intake of bicarb or alka seltzer, prolonged vom, NG suction, diuretics
- causes hypokalemia causing H+ to shift out the ICF and K into cell
Metabolic alkalosis CM
- CNS over-excitability
- Confusion
- Tremors
- Muscle cramps
- Paresthesias:
- tingling of fingers and toes,
perioral - Coma
- N/V/D
- Resp depression
Respiratory alkalosis
H2CO3 deficit in ECF
- caused by hyperventilation like anxiety attack, inc metabolic demand like sepsis, meds, hypoxia, PE or lung disease, CNS lesions, ventilator, head injury
- pH inc, PaCO2 dec, HCO3 neutral
Respiratory alkalosis CM
- CNS over-excitability
- Tachypnea
- Light headedness
- Confusion, blurred vison
- Paresthsia -Numbness of hands and
feet, perioral - Hyperactive reflexes, seizures
- Coma
Tx for respiratory alkalosis
Nonrebreather, dec RR, calm pt
Respiratory acidosis
- excess H2CO3 (excess H+)
- hypoventilation, OD, not breathing enough, anesthesia, narcotics, head injury, pain, pulmonary dx, liver fail, airway obs
Tx for resp acidosis
Vent, NOT bicarb
Respiratory acidosis CM
- hypoventilation
- dyspnea
- respiratory distress
- shallow respirations
- H/A, restlessness,
confusion - tachycardia,
arrhythmias - LOC, stupor, coma
Acute vs chronic resp acidosis labs
Acute: pH dec, PaCO2 inc, HCO3 neutral
Chronic: pH neutral, HCO3 inc
Metabolic acidosis
- HCO3 deficit in ECF (excess acids added or bicarb lost)
- pH dec, PaCO2 neutral, HCO3 dec
- DKA, impair renal, chronic d, salicylate OD, accum lactic acid, cardiac arrest, ketosis, fistula, shock, starvation
Metabolic acidosis CM
- CNS
- Lethargy, drowsiness
- Confusion
- Tremors, muscle cramps
- Paresthesias:
- Tingling of fingers or toes,
perioral - Hypotension
- Hyperkalemia
- Deep breathing
- Kussmaul respirations (DKA)
- Fruity Odor Breath (DKA)
Steps of interpreting ABGs
- Acid or base problem
- Look at CO2 (if opp, resp prob)
- Look at bicarb
- Look at compensation
If uncompensated…
pH is abnormal
If partially compensated…
pH is abnormal, both other numbers are abnormal
If compensated, pH…
Is normal but others are abnormal
If corrected…
All normal; doesn’t always occur (COPD)
tm for met acidosis
sodium bicarb, rapid acting ins
tm for met alkalosis
PPI or H2r antag
