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 feeding**rotten 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 increase**s (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**