TCI Alfentanil

Maitre Model (based on 45 pts) or Scott Model (based on 12 pts) both 3 compartment models

Maitre assumes a larger central compartment and a greater clearance than Scott

Studies suggest:

  • Both Maitre and Scott models under predict plasma concentrations during infusion
  • Maitre model under predicts plasma concentrations after infusion stopped
  • Whereas Scott Model over predicts plasma concentrations

So Maitre model will:

  • Infuse more drug for given target compared with the Scott model
  • And predicted a faster decrement when the infusion is stopped

Suggested dosing:

Dial up effector site conc. of 100ng/ml, then reduce to 60ng/ml after 5mins

Titrate up and down 10ng/ml based on usual parameters (e.g. HR and BP)

Stop infusion 10-20mins before end of surgery

(NB: after 4hr infusion context sensitive half-time is 60mins!)

Bottom Line:

Use Remifentanil as more haemodynamic stability and less response to laryngoscopy. And it wears off in 10 minutes, irrespective of infusion rate or duration!!

Caveat:

It might be worth trying out alfentanil TCI before remifentanil is completely out of stock!

(And then cancelling the rest of the list while you wait for the patient to start breathing!)

Links:

Dosing Regime Suggestion

Open TCI

TCI pdf

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