For cells to function optimally a steady balance between the acids and the bases is necessary Acidbase balance represents homeostasis of hydrogen H ion concentration in body fluids ID: 912229
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Slide1
Acid base balance
Slide2Slide3Key points
For cells to function optimally, a steady balance between the acids and the bases is necessary.Acid-base balance represents homeostasis of hydrogen (H+) ion concentration in body fluids. Minor changes in hydrogen concentration have major effects on normal
cellular function
.
Arterial pH is an indirect measurement of hydrogen ion concentration and
is a
result of respiratory and renal compensational function
.
Arterial blood
gases (ABGs
) are most commonly used to evaluate acid-base balance.
Slide4Key points
The pH is the expression of the balance between carbon dioxide (CO2), which is regulated by the lungs, and bicarbonate (HCO3-), a base regulated by the kidneys.Acid-base balance is maintained by chemical, respiratory, and renal processes.
Chemical
and protein buffers:
Are the first line of defense.
Either bind or release hydrogen ions as needed.
Respond quickly to changes in
pH.
Slide5Key points
Respiratory buffers:Are the second line of defense.Control the level of hydrogen ions in the blood through the control of CO2 levels.When chemoreceptors sense a change in the level of CO2, they signal the brain to alter the rate and depth of respirations.Hyperventilation = decrease in hydrogen ionsHypoventilation = increase in hydrogen
ions
Slide6Key points
Renal buffers:The kidneys are the third line of defense.This buffering system is much slower to respond, but it is the most effective buffering system with longest duration.The kidneys control the movement of bicarbonate in the urine.
High
hydrogen ions = bicarbonate reabsorption
and production
Low hydrogen ions = bicarbonate excretion
Compensation refers to the process by which the body attempts to
correct
changes
and imbalances in pH levels.
Full compensation occurs when the pH level of the blood returns
to normal
If the pH is not able to normalize, then it is referred to as
partial compensation
.
Slide7Slide8Slide9Slide10Key factors
Acid-base imbalances are a result of insufficient compensation. Respiratory and renal function play a large role in the body’s ability to effectively compensate for acid-base alterations. Organ dysfunction negatively affects acid- base compensation
Slide11Slide12Slide13Slide14Slide15Slide16Slide17Slide18To determine the type of imbalance, follow these steps:
Step 1 Look at pH. If < 7.35, diagnose as acidosis. If > 7.45, diagnose as alkalosis.Step 2 Look at PaCO2 and HCO3 - simultaneously. Determine which one is in the normal range.
Then
, conclude that the other is the indicator of
imbalance
.
Diagnose < 35 or > 45 PaCO2 as respiratory in origin.
Diagnose < 22 or > 26
HCO3 -
as metabolic in origin.
Step 3 Combine diagnoses of Steps 1 and 2 to name the type of
imbalance
Slide19Slide20Slide21Slide22Slide23Slide24Slide25Slide26Step 4 Evaluate the PaO2 and the SaO2.
If the results are below the normal range, the client is hypoxic.Step 5 Determine compensation as follows:Uncompensated: The pH will be abnormal and either the HCO3- or
the PaCO2
will be abnormal.
Partially compensat
ed: The pH,
HCO3-
, and PaCO2 will be abnormal.
Fully compensated
: The pH will be normal, but the PaCO2 and
HCO3-will
both be abnormal.
Then
, looking back at the pH will provide
a clue
as to which system initiated the problem, respiratory or metabolic.
If the pH is < 7.40, think “acidosis” and determine which system
has the
acidosis value. If the pH is > 7.40, think “alkalosis” and
determine which
system has the alkalosis
value
Slide27Slide28Slide29Slide30Slide31NANDA Nursing Diagnoses
Respiratory acidosis/alkalosisImpaired gas exchangeIneffective breathing patternMetabolic acidosis/alkalosisDecreased cardiac output
Slide32Slide33Nursing Interventions
For all acid-base imbalances, it is imperative to treat the underlying cause.Respiratory acidosis: Oxygen therapy, maintain patent airway, and Enhance
gas
exchange
(positioning and breathing techniques,
ventilatory
support, bronchodilators,
mucolytics
).
Respiratory alkalosis:
Oxygen
therapy,
anxiety
reduction interventions,
Rebreathing
techniques.
Slide34Nursing Interventions
Metabolic acidosis: Varies with causes. If DKA, administer insulin; If related to GI losses, administer antidiarrheals and provide rehydration; if serum bicarbonate is low, administer sodium bicarbonate (1 mEq
/kg).
Metabolic alkalosis: Varies with causes.
If
GI losses,
administer
antiemetics
, fluids, and electrolyte replacements;
if related to potassium depletion, discontinue causative agent or potassium-sparing diuretic.
Slide35Complications and Nursing Implications
Convulsions, Coma, and Respiratory ArrestSeizure precautions and managementLife-support interventions
Slide36Slide37