Effects On CVS,CNS And Ventilation

Question 0

Propofol

Answer 0

CNS

1. Decrease in CBF
2. Decrease in cerebral oxygen consumption
3. Decrease in intercranial pressure
4. Neuroprotective
5. Anticonvulsant

CVS:

1. Causes vasodilatation both in arteries and veins
2. Decreases pre-load
3. Does not affect cardiac output
4. Numbs the baroreflex effect of heart, heart rate will not pick up in response to decrease in bp
5. Watch out in elderly as they are already hypovolemic too and now you are causing vasodilation

Ventilation:

1. Causes vasodilatation both in arteries and veins
2. Decreases pre-load
3. Does not affect cardiac output
4. Numbs the Ventilatory response to hypercapnia

Question 1

Midazolam

Answer 1

CNS: decreases blood flow and o2 consumption (cerebral metabolism of O2) does NOT decrease ICP, it is NOT Neuroprotective

CVS: When you use Midazolam for induction (0.1-0.3 mg/kg) (Note: not when you use it for anxiolysis, sedation of amnesia 1-2mg) produces a decrease in your BP (SVR X CO) Midazolam does not effect your cardiac output, it effects your SVR by causing vasodilatation.
Note: Cardiac output is the amount of blood (L/min) pumped by heart every min. It is Defined by CO: HRXSV
The chance of causing Midazolam induced hypotension is more likely in hopovolemic patients
Respiratory system:
Generally when you use it for anxiolysis, amnesia and sedation there is minimal depression of ventilation (1-2 mg)
When you use it for induction (0.1-0.3 mg/kg) a rapid intravenous injection and give you apnea especially if you have opioids on board
NOTE: Benzos decrease the ventilatory response to carbon dioxide, this is usually minimal unless you have opioids on board