ABG Flashcards
What is a buffer?
a chemical system that prevents radical change in fluid pH by dampening the change in hydrogen ion concentration when there is excess acid or base
What is normal pH that they body depends on?
7.35 - 7.45 but the best possible pH is 7.4
What is pH?
concentration of hydrogen ions
pH and hydrogen are…
inversely related
As hydrogen concentration goes up, pH goes down
Why is acid base balance necessary?
To maintain homeostasis
All cells depend on it
Drastic fluctuations either acidic or alcalotic can lead to life-threatening disorders
How does the body maintain a pH between 7.35-7.45
Hemeostatic mechanisms and respiratory system like exhaling CO2, buffer system and the renal system
Low pH
Acidic, less than 7.35, increase in hydrogen ions
High pH
alkaline, more than 7.45, decreases in hydrogen irons
Acidosis
blood pH below 7.35. more acid or less base
Alkalosis
blood pH above 7.45, less acid or more base
a base will…
neutralize an acid and promote the excretion of acid
What are some examples of health problems that lead to acid/base imbalance?
Diabetes, COPD, kidney disease
Is an acid/base imbalance a disease?
No, it is a manifestation of an underlying health problem and should be considered in any patient with a serious illness
An acid..
fors hydrogen ions in solution
How do the lung help maintain normal pH?
The lungs blow off or retain CO2
How does the buffer system maintain normal pH?
CO2 is generated in the tissues and transported in plasma as bicarb, the RBC’s hemoglobin buffers hydrogen
How do the kidneys help maintain normal pH?
Kidney reabsorb filtered bicarb in the proximal tubules and generate new bicarb in the distal tubules, where there is a net secretion of hydrogen ion
Kidneys also excrete H+
Kussmauls respirations are
deep rapid breathing
Buffers
- first life of defense
- chemical actions
- Change acids, or neutralize acids
- Can also release H+ if needed
Respiratory system
Changing the level of CO2
- hypercarbic drive
- hypoxic drive
Renal
Change level of HCO3
-kidneys regulate H+ ions or bicarb ions
Hypoventilation
acidosis
CNS depression in both acidosis and alkalosis
HA, weakness, leathery, confusion, can lead to coma and death
Alkalosis and electrolytes
hypocalcemia –> muscles cramping, numbness, tetany
Example of how the body compensates with metabolic acidosis
deep rapid respirations
Why is the potassium level altered in a patient with acid-base imbalance?
In alkalosis, potassium is shifts into the cells for hydrogen. This decreases the potassium in the ECF –> hypokalemia
What does an arterial blood gas tell you?
- Hypoxemia
- Acid base disorder
- pH
- Patients ability to compensate
- O2 status
Respiratory acidosis
- Low pH
- High CO2
- Build up of CO2: caused by pulmonary issues or hypoventilation
- Accumulation/excess of CO2 in blood –> increase H+ –> decreased pH
Respiratory alkalosis
- High pH
- Low CO2
- CO2 deficit due to hyperventilation
- Decreased CO2 in blood –> decrease H+ –> increased pH
Metabolic acidosis
- Acids accumulate d/t ketoacidosis, lactic acids OR bicarb is lost
- pH is low
- HCO3 is low
- CO2 could be normal
Metabolic alkalosis
- Loss of acids d/t gastric loss OR increase in HCO3
- Could be d/t an increase in intake of HCO3
- High pH
What are the degrees of compensation are?
compensated, partially compensated, or uncompensated
How do you determine the level of compensation
pH, PaCO2, and HCO3 are analyzed
How does the body compensate for a metabolic acid-base disorder?
Respiratory system may compensate by retaining or removing CO2.
Respiratory compensation is rapid
How does the body compensate for a respiratory acid-base disorder?
Renal system may compensate by excreting or retaining hydrogen and bicarb.
Renal compensation is slow and can take up to 24 hours
What acid-base imbalance do you expect when a patient has prolonged diarrhea?
Loss of HCO3
Metabolic acidosis
Dehydration
What will the body due to compensate after the patient get metabolic acidosis from diarrhea?
Lungs: increase RR to blow off CO2
Kidneys: retain HCO3 and excrete H+
How does renal disease affect acid-base imbalances?
kidneys have poor reabsorption of HCO3 and secrete H+
What acid-base imbalance do you expect if your patient has prolong vomiting?
Loss of acids
Metabolic alkalosis
What will the body do to compensate after the patient get metabolic alkalosis from vomiting?
Lungs: decrease or maintain regular RR
Kidneys: excrete HCO3 and retain H+
What is the priority nursing intervention if your patient have metabolic acidosis
Perform medication reconciliation
Assess the client’s strength in the extremities.
Obtain a diet history for the past 3 days.
Initiate cardiac monitoring.
Initiate cardiac monitoring.
