Lab 2 test= Reference ranges and their expected changes in various conditions!

Question 1

What is the blood pH reference range?

Answer 1

When pH is between 7.35-7.45 the state is compensated

(acidosis: <7.4 and alkalosis: >7.4).

This is the blood pH reference range.

Question 2

The reference range for anion gap

Answer 2

8-16 mmol/L

Question 3

Parameters and reference range:
The partial pressure of oxygen (mmHg, kPa)

Answer 3

pO2

• *arterial: 88-118 mmHg
  venous: 35-45 mmHg**

Indicates the ability of the lungs to oxygenate blood.

Question 4

Parameters and reference range:
The partial pressure of carbon dioxide (mmHg, kPa)

Answer 4

• *arterial: 35-45 mmHg
  venous: 35-45 mmHg**

Indicates the ability of the alveolar gas exchange to remove
the CO2.
It is directly proportional to the rate of CO2 production,
and inversely proportional to alveolar ventilation.

Question 5

Parameters and reference range:
**SAT (%)**
oxygen saturation (%)

Answer 5

• *venous: 70-80%
  arterial: 90-100%**

oxygen saturation (%); calculated from Hb and pO2
Indicates the fraction of oxygen-saturated hemoglobin
relative to total hemoglobin in the blood.

Question 6

Fraction of inspired oxygen
FiO2

Answer 6

Room air: 0.209 (20.9%)

O2 enriched: 0.21-1.0

>0.5 risk of O2 toxicity

It is the assumed % of O2 concentration participating in
gas exchange in the alveoli.

Question 7

Partial CO2 pressure (mmHg, kPa),

respiratory parameter

Answer 7

pCO2
40 mmHg
(35-45)

Question 8

**HCO3-**
Standard bicarbonate (HCO3-) concentration (mmol/l)

Answer 8

21-24 mmol/l

Bicarbonate concentration of plasma, if the blood is
equilibrated to 40 mmHg pCO2 on 37 °C - it`s value
depends on pCO2 - metabolic parameter

Question 9

ABE
Actual base excess (or demand) or residue (mmol/l)

Answer 9

±3.5 mmol/l

Titratable acidity or basicity; the amount of acid or base
needed to equilibrate blood to pH: 7.4 (pCO2 is stabilized
at 40 mmHg/l on 37 oC) , metabolic parameter

Question 10

TCO2
Total CO2 concentration in plasma (mmol/l)

Answer 10

23-30 mmol/l

i.e. CO2 content
of blood liberated by strong acid. TCO2 is 5% higher than
plasma HCO3
-
. TCO2 gives no direct information about
respiratory function. TCO2 may be ignored, when HCO3
-
result is presented

Question 11

SBE
Standard or in vivo base excess (base demand)

Answer 11

±3 mmol/l

Standard or in vivo base excess (base demand), residue in
the whole extracellular space, metabolic parameter

Question 12

Normal anion gap
(hyperchloraemic)
Diarrhoea

Answer 12

HCO3- Loss

Question 13

Normal anion gap
(hyperchloraemic)

Early kidney failure

Answer 13

H+ retention, decreased ammonia excretion

Question 14

Normal anion gap
(hyperchloraemic)
Renal tubular acidosis

Answer 14

Proximal (Fanconi syndrome) or distal tubular defect

Question 15

Normal anion gap
(hyperchloraemic)
Acidifying substances

Answer 15

NH4Cl

Question 16

Increased anion gap

(normochloraemic)

Azotaemia or uraemia

Answer 16

Advanced kidney failure – organic acid accumulation

Question 17

Increased anion gap
Lactacidosis

Answer 17

Shock, hypovolaemia, poor tissue perfusion, tissue necrosis

Question 18

Increased anion gap
Ketoacidosis

Answer 18

Diabetic ketoacidosis – increased hepatic production of ketone bodies

Question 19

Increased anion gap
Toxicosis

Answer 19

Ethylene glycol toxicosis (also alcohol)

Question 20

Normal anion gap
(hyperchloraemic)
Name cases

Answer 20

Diarrhoea
Early kidney failure
Renal tubular acidosis
Acidifying substances

Question 21

Increased anion gap
(normochloraemic)

Answer 21

Azotaemia or uraemia
Lactacidosis
Ketoacidosis
Toxicosis

Question 22

Metabolic alkalaemia/alkalosis
Ranges

pH
HCO3
BE

Answer 22

pH > 7.4
HCO3- > 28 mmol/l
BE > +3.5 mmol/l

Question 23

Metabolic alkalaemia/alkalosis
effects

Answer 23

 Breathing-depression
 Muscle weakness – hypokalaemia
 hypocalcemia due to the increased Ca2+ binding ability of albumin
 Ammonia toxicosis
 Arrhythmia,
 Paradoxical aciduria

Question 24

Respiratory acidaemia/acidosis
ranges
pH
pCO2
pO2

Answer 24

pH < 7.4
pCO2 > 40 mmHg
pO2 < 40 mmHg

Question 25

Respiratory acidaemia/acidosis
effects

Answer 25

Dyspnoea,
cyanosis,
suffocation,
muscle weakness,
tiredness.

Question 26

Respiratory alkalemia/alkalosis
ranges
pH
pCO2
pO2

Answer 26

pH > 7.4
pCO2 < 40 mmHg
pO2 > 40 mmHg

Question 27

Respiratory alkalaemia/alkalosis
Effects:

Answer 27

**Hyperoxia, the decreased pCO2 : pO2 ratio may lead to apnoea

increased elimination of HCO3
- by the kidneys**

Question 28

Hypoxaemia

Answer 28

(<60 mmHg)

Question 29

hyperoxaemia;

Answer 29

for CO2
hypocapnia or hypercapnia are used.

Question 30

When may cyanosis be detectable?

Answer 30

Under 40-50 mmHg

Question 31

Hypoventilation:

Answer 31

pCO2 > 45 mmHg
(most reliable in arterial blood sample)

• Hypoxemia +-: depends on the degree of hypercapnia, and the FiO2.
• *- low O2 saturation** (depends also on blood Hb concentration, RBC count!)

Question 32

Hypoventilation:
Effects

Answer 32

dyspnoea,
cyanosis
 mildly anxiolytic/sedating treatment

Question 33

Hyperventilation

Answer 33

**PaCO2 < 35mmHg

Hyperoxaemia: usually present together with increased SAT.**

Question 34

Hyperventilation
Causes:

Answer 34

Causes:
 iatrogenic: forced ventilation during anesthesia
(also high FiO2)
 seizures, epilepsy
 excitation
(mild frequently visiting the vet, extreme e.g. shock after accident)
 compensation of severe metabolic acidosis:
Kussmaul-type breathing.

Question 35

Causes of hypoventilation

Answer 35

Causes:
 upper airway obstruction
 pleural effusion
 drugs or disorder affecting central control of respiration e.g. general anaesthesia
 neuromuscular disease, which affects on the respiratory system, also muscle weakness
e.g. hypokalaemia
 overcompensation of metabolic alkalosis

Question 36

Causes of Respiratory alkalemia/alkalosis

Answer 36

Causes:
Increased loss of CO2: hyperventilation
 excitation
 forced ventilation (anaesthesia)
 epileptiform seizures
 fever, hyperthermia
 interstitial lung disease

Question 37

Causes of Respiratory acidaemia/acidosis

Answer 37

Causes:
Upper airway obstruction
 Pleural cavity disease: pleural effusion, pneumothorax

 Pulmonary disease:

• severe pneumonia,
• pulmonary edema,
• diffuse lung metastasis,
• pulmonary thromboembolism

Depression of central control of respiration:

• drugs,
• toxins,
• brainstem disease

 Neuromuscular depression of respiratory muscles

 Muscle weakness e.g. muscle weakness in hypokalaemia
Cardiopulmonary arrest

Question 38

Causes of Metabolic alkalaemia/alkalosis

Answer 38

Causes:
 Increased alkaline intake:overdose of bicarbonates, or feedingrotten food

 Increased ruminal alkaline production:

- high protein intake,

- low carbohydrate intake,

- anorexia,

- hypomotility

 Decreased hepatic ammonia catabolism (liver failure)

 Increased acid loss:

- vomiting,

- gastric dilatation volvulus syndrome,

- abomasal displacement

 Ion exchange: hypokalaemia: due to Henle loop diuretics remember H+/K+ pump!!
(paradoxical aciduria, see Pathophysiology lecture notes!!)

Question 39

Causes of Metabolic acidaemia/acidosis

Answer 39

• * HCO3
• loss: diarrhea, ileus, kidney tubular disturbance**
• * increased acid intake:** i.e. fruits, too acidic silage, an overdose of
• *acidifying drugs** (ammonium chloride), even vitamin C if long term high doses!

 increased acid production e.g. increased lactic acid production, due to anaerobic glycolysis, frequent in anorectic, weak animals

 in cattle grain overdose, leading to volatile acid overproduction

 increased ketogenesis, leading to ketosis due to relative or objective starvation or diabetes mellitus

 decreased acid excretion: renal failure

 ion exchange: hyperkalaemia, remember the H/K pump!!

 some xenobiotic: ethylene-glycol toxicosis: metabolites are acidic molecules, leading to metabolic acidosis, and finally renal failure will worsen it

Question 40

Effects of Metabolic acidaemia/acidosis

Answer 40

Effects:
 Kussmaul-type breathing - hyperventilation (not panting!!)

 Hypercalcaemia: increased mobilisation from bones in case of long term acidosis
(TCa), and decreased binding of calcium ions to albumin (Ca2+)

 Vomiting, depression

 Hyperkalaemia: decreased cardiac muscle activity; sinoatrial, or atrioventricular
block, bradycardia.

 In urine: titratable acidity increases (except for the processes of renal origin)

Question 41

Most importaint buffersystem

Answer 41

carbonic acid-bicarbonate buffer system:

Question 42

What forms the vital buffer system

Answer 42

The kidneys and the lungs