Homeostasis- Isovolemia, Isoionia, Isoosmosis Flashcards
Haematology
In vitro anticoagulation (blood plasma).
Anticoagulant: Na2, K2, Na/K-EDTA (inhibition by irreversibly binding Ca)
Biochem parameters
Measured from serum, using a plain tube or a tube containing clotting activators (Si-oxide/gel).
If measured in plasma -> coagulation is blocked by Heparin
Blood clotting parameters
Anticoagulant: Na2-citrate- 1:9 (& RBC sedimentation test- 1:4).
- Reversible binding of Ca (Ca is always included in the reagent -> restart of the coagulation cascade)
- Least damage on cell metabolism => blood smears, blood transfusion transport bags (max cell life).
Ht/ PCV
Goal: to detect fluid V changes, quantitative changes of RBCs.
Sample: anticoaculated blood (EDTA, heparin)
Method: Microcapillary method / Automated cell counter / Handheld HCT meter
Interpretations:
- Normovolaemic normocythaemia
- Hypovolaemic normocythaemia
- Hypervolaemic normocythaemia
- Polycythaemias: false/ Absolute normovolaemic (physiological, pathological)/ Relative (hypovolaemic)/ complex (hypervolaemic).
- Oligocythaemias (anaemia): false/ Relative hypervolaemic (physiological, pathological)/ Absolute normovolaemic/ complex (hypovolaemic)
Osmolality
270-310 mosmol/kg
Goal: reflects the ion changes of the body (depends on the [] of osmotically active substances & some other small molecules: glucose, KB, urea).
Heparinised plasma (electrolytes), serum.
Mathematically / Osmometer.
Interpretation: Hyperosmolality / Hypoosmolality.
Rapid changes => serious consequences (e.g. hyperglycaemia of DM- if decr too quickly => hypokalaemia, hypophosph, cellular oedema OR incr too quickly => salt poisoning).
Ionogram
[electrolytes] -> basic life processes can occur in the appropriate osmotic environment. (& choose the appropriate fluid therapy).
Sample: heparinised full blood, anticoagulant: Ca equilibrated Na/Li heparinate
Method: ion selective electrodes, spectrophotometry (Cl).
