Acid Base Balance

Acid–base balance

the process of

regulating the pH, bicarbonate concentration,

and partial pressure of carbon dioxide of body

fluids

Scope (acidotic (lower than normal pH) to optimal balance (normal pH and other parameters) in the middle and alkalotic

(higher than normal pH) on the other end

Acid-Base Balance

 Expected in all well

individuals

 Requires normal

physiological functioning

 Indication of homeostasis

Acid-Base Imbalance

 Develops as a

complication of another

underlying condition

 Never considered

“normal,” but may be

“expected” if a chronic

condition (e.g.,

compensation) is present

Acid Production and Excretion

 Cellular metabolism produces acids

 Carbonic acid goes to lungs for excretion

 Metabolic acids go to kidneys for excretion

Review of Respiratory and Renal

Systems Anatomy and Physiology

 Lungs

 Kidneys

Optimal Acid-Base Balance

 Acid excretion keeps pace with acid

production

 Buffers are not overwhelmed

 The blood pH is maintained in the normal

range of 7.35 to 7.45

Acidosis

 Caused by:

- Retention of too much acid

-Loss of too much base

 Respiratory acidosis

-CO2 retention

 Metabolic acidosis

-HCO3 loss or H+ retention

Alkalosis

 Caused by:

-Retention of too much base

- Loss of too much acid

 Respiratory acidosis

- CO2 loss

 Metabolic acidosis

-HCO3 excess or H+ loss

Consequences:

Impaired Cellular and Organ

Function

 When compensatory mechanisms fail, the

following physiological consequences occur:

 Altered cell function, especially in the brain when

CO 2 crosses the blood–brain barrier

 Change in intracellular enzyme activity resulting in

cell dysfunction

 Acidosis: decreases the level of consciousness

(LOC)

 Alkalosis: decreases the LOC and has other

neurological manifestations; may cause

dysrhythmias

Risk Factors

All individuals are at risk, regardless of age,

race, or socioeconomic status. Those at

greatest risk have one of four risk factors:

 Excessive production or intake of metabolic acid

 Altered acid buffering due to loss or gain of

bicarbonate

 Altered acid excretion

 Abnormal shift of H+ into cells

 Very young and very old at greatest risk

 Very young:

-Immature lungs, kidneys, thermoregulation, and

metabolic processes

-Degree of risk varies based on weight and

gestational age at birth

 Very old:

-Decreased renal reserve

-Ability to correct and compensate for imbalance

less effective

Primary Prevention

-Prevent risk factors of health conditions and

situations that can cause acid–base

imbalances. A few examples include:

 Healthy eating habits

 Safe weight loss

 Smoking prevention or cessation

 Poison control measures

 Safe food handling