Predicted Exam Questions Flashcards
What is the principle of a TCI device?
delivery of a variable-rate infusion to achieve and maintain a constant, calculated target concentration.
How is the maintenance rate of TCI calculated?
Ongoing infusion rate is calculated to take into account the loss of drug from the central compartment due to both distribution and elimination.
How much, in %, of potassium is within the ECF?
2%
Which organ contributes the most to K+ buffering?
skeletal muscle, due to its largest intravascular volume
List hormones that regular body potassium
insulin
adrenaline
Hydrogen ion -> increase in ECF hydrogen is associated with a net movement of K+ out of the cell
Aldosterone
Renal K+ handling influenced by?
- Dietary intake -> increases ROMK and increased Na/K ATPase activity of intercalated A cells
- plasma potassium -> directly proportional to filtered load
- Aldosterone -> directly via K+ increase -> stimulates ROMK in principal cells
- ATII -> Inhibition of K+ excretion by decreasing ROMK activity in principal cells
- High sodium delivery to DCT stimulated K+ secretion
How does high Na+ delivery increase K+ secretion
influence on both principal and intercalated cells
Principal: sodium entry -> depolarisation -> drive K+ out of cell via electrical gradient. Na/K ATPase channel increase K+ pumped into cells
Intercalated cells -> activation of BK channels
Why is oxygen paramagnetic?
It is attracted by magnetic field
Most other molecules are repelled
It’s due to the unpaired electrons in the outer shells of the oxygen atoms.
List some techniques used for temperature measurement
- liquid expansion thermometer.
- Gas expansion thermometer
- Bimetallic strips: two metals with different coefficient of thermal expansion.
- Infrared thermometer
- Thermistor: resistance increases linearly with temperature.
Why is mercury chosen for liquid expansion thermometer?
linear expansion over the temperature of interest
How does infrared thermometer work?
Relies on pyroelectric effect - the generation of a temporary polarisation in the molecules of substances when they are exposed to certain frequencies.
Potential difference generated is proportional to change in temp.
What is dew point?
the temperature the air needs to be cooled to in order to achieve a relative humidity of 100%
What is the definitive diagnosis of MH?
exposure of muscle biopsy to halothane and caffeine
Boundary of femoral triangle
superiorly bound by inguinal ligament
medially by adductor longs
laterally by sartorius
Describe the insertion point of femoral CVC
1cm inferior to the inguinal ligament
1cm medial to the maximal pulse of the femoral artery
