Critical Care

Question 1

Definition of low BP in shock

Answer 1

systolic BP <90 OR MAP <65 for 1h+, OR need for vasoconstrictors to maintain BPs above this, OR reduction in systolic of 40 from baseline, despite adequate fluid resus

Question 2

Normal blood glucose

Answer 2

4-5.4mmol/L

Question 3

How to calculate maintenance fluid requirements

Answer 3

4, 2, 1
4ml/kg/hr for first 10kg
2ml/kg/hr for second 10kg
1ml/kg/hr for every 1kg after that (over 20)

Question 4

Normal ventilation:perfusion ratio (in health)

Answer 4

0.95

Question 5

What is shunt?

Answer 5

an area with no ventilation but preserved bloodflow

Question 6

What is the Haldane effect?

Answer 6

deoxygenated Hb has a higher CO2 buffering capacity than oxygenated Hb - favours CO2 pickup in systemic venous circulation, and CO2 offloading in the lungs

not 100% sure about this (see oxygen therapy notes)

Question 7

What is the Bohr effect?

Answer 7

more chronic exposure to hypoxia will increase 2,3-DPG in RBCs - shifts dissociation curve to the right, increasing oxygen delivery to tissues