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Acid base disorders
BY : MUHANNAD ALI ASIRI432800225
Acid base balance
Acid-base balance refers to the mechanisms in the body uses to keep its fluids close to normal pH (that is, neither basic nor acidic) so that the body can function normally.
Arterial blood pH is normally : between 7.35 and 7.45
What is acid base balance
Why is acid-base balance important?
Because any disturbance in ph range effect on multi system and process in body as : Enzyme systems, oxygenation, muscle, nerve and metabolic functions of the body work best within a specific pH range.
Definition of acid-base disorders
An acid base disorder is a change in the normal value of extracellular pH that may result when renal or respiratory function is abnormal or when an acid or base load overwhelms excretion capacity .
Effects of acidosis: 1-depresses CNS2-decrease plumonary blood flow3-arrhythmias4-hyperkalemia
Effect of alkalosis :1- decrease cerbral blood flow2-seaizures3-arrhythmias
How to recognize abnormal acid- base? normal range
Abnormal ph (7.35-7.45)
Abnormal Hco 3 (22-24 mEq / L)
Abnormal pCO2 ( 35-40 mm Hg)
Abnormal anion gap (10-14 mEq / L )
REMEMBER
HCO3 level indication of METABOLIC problem
pCO2 level indication of RESPIRTORY problem
Henderson-hasselbach equation
[H+] = 24 ×
PCO2HCO3
-
Relationship between [H+] & CO2 & HCO3-
CO2 [H+]
CO2 [H+] (Positive
relationship)
HCO3- [H+]
HCO3- [H+] (Inverse
relationship)
Relationship between [H+] & pHpH [H+] pH [H+]
7.807.75
1618
7.307.25
5056
7.707.65
2022
7.207.15
6371
7.607.55
2528
7.107.00
7989
7.507.45
3235
6.956.90
100112
7.407.35
4045
6.856.80
141159
Relationship between [H+] & CO2 & HCO3- & ph
CO2 [H+] pH (respiratory acidosis)
CO2 [H+] pH (respiratory alkalosis)
HCO3 - [H+] pH
(metabolic alkalosis) HCO3
- [H+] pH (metabolic acidosis)
Some Causes of acid base disturbance (generally)Dm (m a)Shock ( septic,hypovolemic,cardognic) (m a)Renal failure (m a)Vomiting (m al)Diuretics (m al)Asthma (r al)Hyperventilation syndrome (r al)Copd (r a)Myasthenia gravis (r a)
Response to acid – base disturbance:H +
loadECF lung ICF Renal
Bone
Buffers
Mainly
Hco3
co2
Respiratory
controlCe
llular Hpo4
(weak)
H+ excret
ion
bicarbonat
e reabsorptio
n
Releas
e bon
e salt
H +
-K+
exchange
Ca2 ++H2PO4
In chroni
c metab
olic acidosi
s
H2CO3 CO2
Acid excretion
Hyperventilation
hyopventilation
Immediately minute
s
hours days Very slow
Compensatory MechanismsCompensation is the body’s way of restoring
a normal blood pH
Compensation DOES NOT treat the root of the problem – the reason for the acid-base imbalance is STILL THERE!!!
Simple vs Mixed acid base distrbance
Simple When compensation is appropriate
MixedWhen compensation is inappropriate
Remember: If abnormal ph (7.35-7.45) Acidosis or AlkalosisIf abnormal Hco3 Metabolic causeIf abnormal pCO2 Respiratory cause
TYPESMETOBLIC ACDOSISMETOBLIC ALKLOSISRESPIRTORY ACDOSISRESPIRTORY ALKLOSIS