1. Acid-Base Basics Chemistry of Life
Like fluid and electrolytes, acid-base balance is very important to your nursing practice. So when it comes to acids and bases, the difference b/w life and death is balance. It is crucial to maintain acid-base balance because cell enzymes function within a very narrow pH range. The body’s acid-base balance depends on some delicately balanced chemical reactions.
For example, postop patients can easily develop respiratory acidosis; a hysterical patient may develop respiratory alkalosis, a client with DM can develop metabolic acidosis and a pregnant female can develop metabolic alkalosis.
To function, the body is constantly working to maintain a balance (homeostasis) between acids and bases. Without balance, cells cannot function properly.

2. Acid-Base Balance: Basics Chemistry Facts
Acids   
                       
Acid gives up a hydrogen ion
Proton donors [H+]
A base/alkali accepts a hydrogen ion
Proton acceptor [H+]
Major base in the body: BICARBONATE (HCO3)
Acids react w/carbonates & bicarbonate to form CARBON DIOXIDE
Carbon Dioxide
Major lung chemical [acid]
Acids react with bases to form H2O and a salt = Neutralization reaction because both the Acid and Base are neutralized
i.e. Carbonic acid= HCO3 + H+ = Carbon dioxide + Water
Release/donate H ions when
Dissolved in H2O.
Bases
                        
Before assessing a patient’s acid-base balance, you need to understand how Hydrogen (H+) affects acids, bases and ph. The acidity or alkalinity
of a solution depends on its H ion concentration. The acidity or alkalinity of a solution depends on its H ion concentration.
ACIDS: AN ACID IS A SUBSTANCE THAT CAN DONATE HYDROGEN TO A BASE. EX: HCL ACID, NITRIC ACID, CARBONIC ACID (H2CO3).
Q: WHAT MAKES AN ACID AN ACID? THE HYDROGEN ION (H+). Release H ions when dissolved in H2O.
BASE: A BASE IS A SUBSTANCE THAT CAN ACCEPT OR BIND HYDROGEN (H+). EX: AMMONIA, LACTATE ACETATE, BICARBONATE
Q: WHAT MAKES A BASE A BASE? THE BICARBONATE ION (HCO3-). HYDROGEN ACCEPTOR
BICARBONATE (HCO3-): MAJOR KIDNEY CHEMICAL. MOST COMMON BASE IN HUMAN BODY
Q: IF MANY H+ IONS ARE PRESENT IN A LIQUID, IS THIS LIQUID AN ACID OR BASE? AN ACID
Q: WHAT HAPPENS TO THE PH OF THIS LIQUID?
A: THE PH DECREASES. THE MORE ACIDIC A SOLUTION, THE LOWER THE PH. THE GREATER THE CONCENTRATION OF H+, THE MORE ACIDIC, THE LOWER THE PH. The more H ions present, the more acidic the fluid.
Q: DOES THIS LIQUID, IF INFUSED INTO A PATIENT, MAKE THE PATIENT ACIDIC (ACIDOTIC) OR BASIC (ALKALOTIC)?
A: ACIDOTIC, BECAUSE H+ IONS ARE ACIDIC
An increase in H ion concentration leads to ACIDITY; a decrease leads to ALKALINITY
A reaction of an acid and a base to form water and a salt is neutralization reaction because both the acid and base are neutralized

3. Homeostatic MechanismsPh
Body fluid ph: measure of the body’s fluid free H+ ion level
Buffer systems [chemical]
Bicarbonate
Phosphate
Protein/Hemoglobin
Kidneys
Lungs
These homeostatic mechanisms help keep the ph within a normal range ( ). This value has the narrowest range of normal and the tightest control mechanism of all body fluids.
pH refers to the concentration of Hydrogen [H] in a solution. The higher the concentration of H ions in a solution, the lower the pH. The opposite, higher pH indicates a lower concentration of H ions in a solution.
The body has three mechanisms by which it regulates acid-base balance to maintain the arterial pH between 7.35 to When pH rises or falls, three regulatory systems come into play.
Buffer systems, respiratory and kidneys systems are the 3 mechanism that help balance pH
Chemical buffers act immediately to protect tissues and cells. These buffers instantly combine with the offending acid or base neutralizing harmful effects until other regulator take over.
Respiratory system uses hypoventilation or hyperventilation as needed to regulate excretion or retention of acids within minutes of a change in pH & reaches maximum effectiveness in hours
The kidneys kick in by excreting or retaining acids and bases as needed. Renal regulation can restore normal hydrogen ion concentration within hours or days. It takes the renal response takes 2 to 3 days to respond maximally, but the kidneys can maintain balance indefinitely in chronic imbalances

4. pH Concentration of hydrogen (H) in a solution
A chemically neutral solution has a pH of 7.00
Normal body pH is 7.35–7.45
Below 7.25 or above 7.55 is considered life-threatening
Above 7.8 (alkalosis) or below 6.8 (acidosis) usually is fatal
7.4 indicates a ratio of 20 parts bicarbonate [base] to 1 part carbonic acid
Measured on a scale from ) [acidic] to 14 [very alkalotic]. pH reflects overall H+ concentration in body fluids. PH of a solution can range from 1-14.
THE HIGHER THE AMOUNT OF H+ IN THE BLOOD, THE LOWER THE PH: Acidity : Increase in H+ concentration = Acidity.
THE LOWER THE NUMBER OF H+, THE HIGHER THE PH. (Alkaline)
THE NORMAL PH OF ARTERIAL BLOOD IS SLIGHTLY HIGHER ALKALINE THAN VENUS AND HAS A NORMAL RANGE OF 7.35 TO FOR NORMAL ENZYME AND CELL FUNCTION AND NORMAL METABOLISM, THE BLOOD’S PH MUST REMAIN IN THIS NARROW RANGE.
IF THE BLOOD IS ACIDIC, THE FORCE OF CARDIAC CONTRACTION DIMINISHES.
IF BLOOD IS ALKALINE, NEUROMUSCULAR FUNCTION BECOMES IMPAIRED.
A BLOOD PH BELOW 6.8 OR ABOVE 7.8 IS USUALLY FATAL IF UNTREATED.
Generally pH is maintained in a ratio of 20 parts HCO3 to 1 part carbonic acid

5. Buffer Systems Buffers-
Chemically change strong acids into weaker acids or to bind acids to neutralize their effect
Primary regulator of acid-base balance
Function:
Minimize effect of acids on blood pH
Three other buffer systems in the body include
Phosphate, Protein/Hemoglobin
Buffer pairs circulating in the blood respond to pH changes very quickly. immediate response
examples
a. carbonic acid ---> bicarbonate
1. interstitial fluid and plasma buffering
Bicarbonate-carbonic acid buffer system is responsible for more than half of the buffering.
Buffers act chemically to change strong acids into weaker acids or to bind acids to neutralize their effect.
They react either as an acid (releasing a H+ ion) or as a base (bind a H+ ion).
Attempt to bring fluid as close as possible to normal body fluid pH (7.35 to 7.45)
Phosphate is active in ICF. Acts in the same manner as the bicarbonate system
Reacts w/either an acid or base to form compounds that will slightly alter pH
This system proves effective especially in renal tubules where phosphates exist in greater concentration: Urine buffering:  Na2 HPO4  +  H+  ---->  NaH2 PO4  +  Na+
Protein is a mix of plasma proteins and globin-Work in and out of cell, in other words, ICF and ECF proteins.
Most plentiful buffers in body
Composed of Hemogobin & other proteins
Behave chemically like bicarbonate.
They bind w/acids and bases to neutralize them
Example: in RBC: Hgb combines w/Hydrogem ions to act as a buffer

6. Acid-Base Regulation: Buffer System
Bicarbonate buffer systems
Body’s primary buffer system
Buffers blood and interstitial fluids
Bicarbonate-carbonic BS
Buffer system maintains 20:1 ratio between bicarbonate & carbonic acid & normal pH
Bicarbonate buffer system is the body’s primary buffer system
Mainly responsible for buffering blood and interstitial fluid. This system relies on a series of chemical reactions in which pair of weak acids and bases such as carbonic acid and bicarbonate combine with stronger acids such HCL and bases to weaken them.
Bicarbonate–carbonic acid buffer system is responsible for more than half of the buffering
Normally, ECF has a ratio of 20 parts bicarbonate to 1 part carbonic acid. The bicarbonate and carbonic system must be carefully controlled to maintain this ratio. If it is either increased or decreased, the 20:1 ratio is no longer in effect.
In this process, the buffer system maintains the 20:1 ratio between bicarbonate and carbonic acid and the normal ph.
Main buffer of the ECF
Once in ECF, it is kept at a level 20 times greater than that of carbonic acid
Bicarbonate-carbonic acid: 20 parts to 1 part (20:1) should be maintained always.
Most common base in human body fluids: bicarbonate (HCO3-)
Most common acid: carbonic acid

7. Respiratory Buffer: Lungs
Under control of _________: control/regulate blood levels of CO2 & the H2CO3 content
CO2: powerful stimulator of resp. center
Chemoreceptors (Brain):
Sense pH change & vary rate & depth of breathing to regulate CO2 levels
Hypoventilate & hyperventilate
respiratory acidosis and alkalosis
To assess effectiveness of ventilation: PaCO2 (Partial pressure of carbon dioxide in arterial blood)
Normal PaCO2 : mm Hg
THE SECOND LINE OF DEFENSE AGAINST ACID-BASE IMBALANCES IS THE RESPIRATORY SYSTEM.
LUNGS: Under the control of CNS (MEDULLA), the lungs control/regulate blood levels of CO2 & thus the carbonic acid (H2CO3) content of ECF.
Chemoreceptors in the medulla of the brain sense those pH changes and vary the rate and depth of breathing to compensate.
The respiratory system alters the breathing rate and depth. Because carbon dioxide dissolves in blood and combines w/water to form CARBONIC ACID, retaining or blowing CO2 helps retain or eliminate acids from the body.
THE LUNGS ADJUST VENTILATION IN RESPONSE TO THE AMOUNT OF CO2 IN THE BLOOD.
A rise in PaCO2: powerful stimulator of resp. center.
DO THE LUNGS COMPENSATE QUICKLY? YES THEY DO. Respond in minutes & reach maximum effectiveness in hours.

8. RR CO2 CO2 & Hyperventilation pH Blowing off CO2
As the amount of CO2 begins to rise above normal in the brain, blood and tissues, these central receptors trigger the neurons to increase the rate and depth of breathing; this is called HYPERVENTILATION. As a result, more CO2 is “blown off” from the lungs and the amount of CO2 (carbonic acid level) in ECF decreases. When the amount of arterial CO2 returns to normal, the rate and depth of breathing return to levels that are normal for the person.
[Breathing faster or deeper eliminates more carbon dioxide from the lungs. The more carbon dioxide that is lost, the less carbonic acid that is made and, as a result, pH rises. The body detects that pH change and reduces carbon dioxide excretion by breathing slower or less deeply.]
DURING HYPERVENTILATION, THE BODY COMPENSATES WITH QUICK, DEEP, RAPID BREATHING, SO THE MORE CO2 THAT IS LOST, THE LESS CARBONIC ACID (H2CO3) THAT IS MADE, AND AS A RESULT THE PH WILL RISE.
**REMEMBER: FASTER, DEEPER BREATHING ELIMINATES CO2 FROM THE LUNGS, WITH LESS H2CO3 BEING FORMED, SO THE PH WILL RISE. PATIENT’S RATE OF BREATHING INCREASES (RR), SO THE BODY “BLOWS OFF” CO2 THEREBY LEADING TO A DROP OR DECREASE IN CO2 LEVEL.
ACID-BASE: RESPIRATORY ALKALOSIS (Carbonic acid deficit)- Any clinical condition that increases respiratory rate or depth [Primary sign] can cause the lungs to eliminate, or blow off, carbon dioxide. Because carbon dioxide is an acid, eliminating it causes a decrease in PaCO2 along with an increase in pH-alkalosis.
A major effect of alkalosis is hyperexcitability of the nervous system. Peripheral nerves are affected first, resulting in spontaneous nervous stimulation of muscles. Spasms and tetanic contractions and possibly extreme nervousness or convulsions result. Severe alkalosis can cause death as a result of tetany of the respiratory muscles.
CO2

9. CO2 RR CO2 & Hypoventilation pH Body retains
If the amount of ECF free hydrogen ions is too low, then the amount of CO2 also is too low. Central receptors sense these low CO2 levels and stop or slow the neuron activity in the respiratory centers of the brain, decreasing the rate and depth of breathing (hypoventilation). As a result, less CO2 is lost through the lungs and more CO2 is retained in arterial blood. [Respirations are inhibited if the center senses low H or CO2 levels]
DURING HYPOVENTILATION, THE BODY COMPENSATES WITH SLOW, SHALLOW BREATHING CAUSING MORE CO2 TO BE RETAINED, too much carbonic acid, THEREBY CAUSING THE PH TO DROP. REMEMBER THAT THE SLOWER, SHALLOWER BREATHING WILL REDUCE CO2 EXCRETION, LEADING TO A FALL IN PH.
HOW DO THE KIDNEYS HELP? KIDNEYS TRY TO COMPENSATE FOR A DROP IN PH BY HOLDING ON TO BICARBONATE (HCO3).
PATIENT’S RATE OF BREATHING SLOWS, THE BODY WILL “RETAIN/HOLD” CO2 & WHEN THIS HAPPENS, THE LEVEL OF CO2 WILL INCREASE.
ACID-BASE: R. ACIDOSIS (Carbonic acid excess)-When a patient hypoventilates, [ALVEOLAR HYPOVENTILATION] carbon dioxide builds up in the bloodstream and pH drops below normal. Alveolar hypoventilation occurs because the body cannot rid the itself of enough CO2 to maintain a heatlhy ph. Compromise in the essentials of breathing will cause a respiratory acidosis. Think BREATHING!
The major effect of acidosis is depression of the central nervous system. When the pH of the blood falls below 7.35, the central nervous system malfunctions, and the individual becomes disoriented and possibly comatose as the condition worsens.
Body retains RR

10. Renal Control: Kidney Kidneys: 3rd line of defense
Movement of bicarbonate: 1st renal control mechanism
Change the excretion rate of acids and the production and absorption of bicarbonate ion
Formation of acids: 2nd renal control [phosphate buffering system]
Formation of ammonium: 3rd renal control
Slow to compensate but are the most effective compensating mechanism
The kidneys serve as yet another mechanism for maintaining acid-base balance in the body. They can reabsorb [retain] acids and bases or excrete them into urine. They can also produce bicarbonate to replenish lost supplies. Such adjustments to pH can take the kidneys hours or days to complete. As with other acid-base regulatory systems, the effectiveness of the kidneys changes with age.
The kidneys also regulate the bicarbonate level, which reflects the metabolic component of acid-base balance. Normally, the bicarbonate level is reported with arterial blood gas (ABG) results. The normal bicarbonate level is 22 to 26 mEq/L.
Under normal conditions, the kidneys reabsorb and conserve all of the bicarbonate they filter. The kidneys can generate additional bicarbonate and eliminate excess H+ ions as compensation for acidosis.
The concentration of bicarbonate in the plasma is regulated by the kidneys.
So, essentially the kidneys excrete or retain hydrogen ions and form or excrete bicarbonate ions in response to the pH of the blood.
They can reabsorb acids and bases or excrete them into urine. They can also produce bicarbonate to replenish lost supplies. Such adjustments to ph can take the kidneys hours or days to compete.
If the blood contains too much acid, or not enough base, pH drops and kidneys reabsorb sodium bicarbonate. The kidneys also excrete hydrogen along with phosphate or ammonia. Although urine tends to be acidic because the body usually produces slightly more acids than bases, in such situation, urine becomes more acidic than normal.
If blood contains more base and less acid, pH rises. The kidneys compensate by excreting HCO3 and retaining more H ions. As a result, urine becomes more alkaline and blood HCO3 level drops. Conversely, if blood contains less HCO3 and more acid, pH drops.
Ammonia (NH3), which is formed during normal protein breakdown, is converted into ammonium (NH4). The ammonia is secreted into the urine, where it can combine with H+ ions to form ammonium. Ammonium traps the H+ ions and then allows them to be excreted in the urine. Result: loss of H+ ion and increase in blood ph.

11. Helping Out: Bicarbonate System
Lungs assist by:
______________________________
Kidneys: __________________________
HOW DO THESE TWO SYSTEMS HELP OUT THE BICARBONATE SYSTEM?
LUNGS: HELP OUT BY REGULATING THE PRODUCTION OF H2CO3 (CARBONIC ACID)
KIDNEYS: HELP OUT BY REGULATING THE PRODUCTION OF HCO3 (BICARBONATE)

12. Fast Slow Acid – Base Balance CO2 + H20 H2CO3 H+ + HCO3- Lungs Kidneys
Metabolic
Respiratory
If the respiratory system disturbs the acid-base balance, the kidneys compensate by altering levels of bicarbonate and hydrogen ions.
When PaCO2 is high (a state of acidosis), the kidneys retain bicarbonate and excrete more acid to raise the pH.
When PaCO2 is low (a state of alkalosis), the kidneys excrete bicarbonate and hold on to more acid to lower the pH
If metabolic disturbance is the primary cause of an acid-base imbalance, the lungs compensate in one of two ways.
When a lack of HCO3 causes acidosis, the lungs increase rate of breathing, which blows off CO2 and helps to raise the pH to normal.
When an excess of HCO3 causes alkalosis, the lungs decrease the rate of breathing, which retains CO2 and helps lower ph.
Fast
Slow

13. ACID-BASE IMBALANCE What Happens? When either the HCO3- or H2CO3
increases or decreases resulting in 1:20 ratio no longer being maintained:
ACID-BASE IMBALANCE
A primary disease or process may alter the other side of the ratio (i.e. CO2 retention in pulmonary disease). The compensatory process attempts to maintain the other side of the ratio (increased renal bicarbonate reabsorption).When the mechanism fails, an acid-base imbalance results.
Respiratory imbalances affect carbonic acid concentrations. Metabolic imbalance affect the base bicarbonate.
Acidosis can cause an increase in Carbonic acid (respiratory acidosis) or a decreases in bicarbonate (m. acidosis)
Alkalosis can be caused by a decrease in carbonic acid (respiratory alkalosis) or an increase in bicarbonate (m. alkalosis)

14. pH: 7.35-7.45 PaCO2: 35-45 mm Hg HCO3: 22-26 mEq/L Acid-Base Balance
pH is an expression of the extent to which the blood is alkaline or acid. Normal value: 7,35 to 7.45
PaCO2: Partial pressure [P] of carbon dioxide [CO2] in arterial blood [A]: Normal values: mm Hg-This indicates the amount of carbon dioxide in the blood.
HCO3: Level of plasma bicarbonate. An indicator of metabolic acid-base status. Normal value: mEq/L.

15. Base deficit/Excess:-2 to +2 mEq/L SaO2 saturation: >95% to 100%
Acid-Base Balance
Base deficit/Excess:-2 to +2 mEq/L
SaO2 saturation: >95% to 100%
PaO2: mm Hg
BASE DEFICIT & BASE EXCESS: Amount of blood buffer.: IT IS WHAT MUST BE ADDED TO RESTORE A NORMAL PH. In other words, it indicates the amount of excess or insufficient level of bicarbonate in the system
The BD/BE is a quick indication of the metabolic component of the patient's condition. A value outside of the normal range (-2 to +2 mEq) suggests a metabolic cause for the abnormality.
The base excess is defined as the amount of H+ ions that would be required to return the pH of the blood to 7.35 if the pCO2 were adjusted to normal.
Alkalosis is present when this value is abnormally high and an Acidosis is present when this value is abnormally low.
PaO2 [partial pressure [P] of oxygen [O] in arterial blood]: reflects body’s ability to pick up O2 from the blood or the amount of O2 in the blood.
Low PaO2=hypoxemia & can cause HYPERVENTILATION.
VALUE ALSO GIVE INDICATIONS IN ORDER TO MAKE THE NECESSARY ADJUSTMENTS IN THE CONCENTRATION OF O2 BEING ADMINISTERED TO THE PATIENT.
SaO2[arterial oxygen saturation]: measures % of available HBG which is fully saturated/combined with O2.
Both PaO2 & SaO2 give information about the patient’s oxygenation.

16. Factors Affecting Acid-Base/Body Fluids/E-Lytes
Age
Gender & body size
Illness
Medical dx, meds & surgery

17. ALKALOSIS: PH & HCO3 TRAVEL TOGETHER: ELEVATOR EFFECT: GOING UP (ALKALOSIS); GOING DOWN (ACIDOSIS).
ACIDOSIS: SEESAW EFFECT: ONE GOES UP, THE OTHER GOES DOWN.
PH DROPS (RESPIRATORY ACIDOSIS) & CO2 (INCREASES)
PH INCREASES (RESP. ALKALOSIS) & CO2 (DECREASES)
Respiratory imbalance: affect carbonic acid concentrations
Metabolic imbalances: affect base bicarbonate
Memory jogger
Remember, PaCO2 and pH move in opposite directions. If PaCO2 rise,then pH falls, and vice versa

19. Elevator Effect

20. Anion Gap Cation-anion difference
Relationship among body cations (+) & anions (-)
Helpful in dx & treating acidotic conditions
Increases in gap = too much acid in blood (acidosis) due to
i.e. DKA, Lactic acidosis
When acid is added to the body, the H ion increases and the HCO3 decreases. In addition, the concentration of the anion, which is associated with acid, increases. This change in the anion concentration provides a convenient way to analyze and help determine the causes of a metabolic acidosis by calculating what is called the anion gap.
AG is the relationship among the body’s cation’s and anions.
[+] Charged Cations: Ca, Mg, K, Ma [-] charged Anions: HCO3, CL, Ph
Na accounts for more than 90% of the circulating cations.
CL & HCO3 account for 85% of the counterbalancing anions.
HOW IS ANION GAP MEASURED? Anion gap is measured after taking a blood sample. One way to calculate the anion gap is to add the number of chloride and bicarbonate anions together and subtract them from the number of sodium cations. Sodium and potassium are two of the most important elements in the body. By subtracting the chloride and bicarbonate anions from the sodium cation, the resulting measurement provides an estimate of the total amount of anions in the blood (besides chloride and bicarbonate anions).
WHY IS IT HELPFUL TO MEASURE ANION GAP? Measuring anion gap helps to diagnose and treat a condition known as acidosis. Acidosis is when there is too much acid in the blood. There are many different types of acidosis, and each type is named for its cause

21. Looking at the “+” & “-” Side of Things
CATIONS
ANIONS
“+” charged ion
Types
____, ____
____ , ____
[-] charged ion
Types
______
A cation is an atom or a molecule which is positively charged, i.e. has more number of protons than electrons.
Examples: Ca+, Mg+, K+, Na+, Iron (Fe2+), and Lead (Pb2+)
An anion is an atom or a molecule which is negatively charged, i.e. has more number of electrons than protons.
Examples: HCO-3, Cl-, Ph-
Anion: A Negative ION

22. Anion Gap 140 – (25+105)= 140 - (130) = 12 mEq/L GAP= 10 (Normal)
Normal value: 8-16 mEq/L
Calculation of anion gap: based on Na, Cl, HCO3:
In the example, the chloride level is 105 mEq/L, the bicarbonate levelis 25 mEq/L, and the sodium level is 140 mEq/L. To find the anion gap, first add the chloride and bicarbonate levels to get a total of 130 mEq/L. Then subtract that total from the sodium level of 140 mEq/L, which leaves 10mEq/L
High anion: metabolic acidosis
Hyperchloremic m. acidosis aka: Normal anion gas acidosis: caused by loss of HCO3 ions via the kidney or GI tract with a corresponding increase in Cl ions.
CL level > 106 mEq/L
Important in analyzing acid-base disorders

23. Anion Gap High Anion gap m. acidosis
Too much acid accumulated
Seen with Lactic acidosi, DKA, Hyperchloremia
Normal anion gap [aka as hyperchloremic m. acidosis]
Direct loss of HCO3 ion
Diarrhea, fistula (GI) or renal causes
Abnormally low gap: HYPONATREMIA, multiple myeloma [Bone Cancer]
An increase in the anion gap that's greater than 14 mEq/L indicates an increase in the percentage of one or more unmeasured anions in the bloodstream. Increases can occur with acidotic conditions characterized by higher-than-normal amounts of organic acids. Such conditions include lactic acidosis and ketoacidosis. Clinically: 2 forms m. acidosis exist according to the serum anion gap
An anion gap occurs because not all electrolytes are measured.
HIGH Anion gap acidosis: TOO MUCH ACID
Excess accumulation of fixed acid
A high anion gap will be present regardless of what the pH and HCO3 are. Seen with Hyperchloremia.
The anion gap remains normal for certain other conditions, including hyperchloremic acidosis,renal tubular acidosis, and severe bicarbonate-wasting conditions, such as biliary or pancreatic fistulas and poorly functioning ileal loops.
A normal anion gap in a patient with m. acidosis indicates that the acidosis is most likely caused by a loss of bicarbonate ions by the kidneys or the GI tract. In either case, a corresponding increase in CL ions also occurs. Chloride can increase in response to the kidneys excretion of bicarbonate.
Normal Anion gap [aka as Hyperchloremic m. acidosis]: LOSS of HCO3
Results from a direct loss of HCO3 ions: Diarrhea, fistula [GI] or renal causes
A fistula is an abnormal connection between an organ, vessel, or intestine and another structure. Fistulas are usually the result of injury or surgery. It can also result from infection or inflammation.
Abnormally Low gap: Hyponatremia or possible Multiple myeloma [bone marrow CA].