Questions and Answers
Diprivan Questions and Answers - Propofol, TCI (target controlled infusion)
1. Q: What pharmaceutical methods have been used to reduce the incidence of pain on injection on induction of anaesthesia with propofol??2. Q:What are the side effects if any of inadvertent intra-arterial infusion of propofol?
4. Q: Will any electrical equipment in the OR interfere with the functioning of `Diprifusor` TCI?
5. Q: Is propofol suitable for use in asthmatic patients ?
6. Q: Can propofol be diluted in 10% glucose solution ?
7. Q: What drugs can be co-administered with `Diprivan` through a Y-piece connector ?
8. Q: Does haemodialysis or haemofiltration affect the blood concentration of propofol ?
9. Q: Propofol has been reported to turn urine green, what information is available in the medical literature ?
10. Q: Does the Diprivan pre-filled syringe contain silicone and if so how much?
11. Q: How sterile is the pre-filled syringe?
12. Q: What is the mechanism of the antimicrobial action of EDTA?
13. Q: Are there any reports of Diprivan causing corrosion of infusion equipment?
14. Q: Is there any Gluten in Diprivan?
15. Q: Does Diprivan contain any mercuric compounds or are they involved in the manufacture? Is it suitable for use in patients with a known allergy to mercury containing compounds?
16. Q: Is the dose of Diprivan, required to induce and maintain anaesthesia, affected by the alcohol intake of patients?
17. Q: How do you determine the Keo for Diprivan and what is its value?
18. Q: Can lidocaine be added to overcome pain on injection when using Diprifusor TCI?
19. Q: Should actual or lean body weight be used when inputting weight data for an obese patient into the "Diprifusor" pump?
20. Q. Will any electrical equipment in the OR interfere with the functioning of "Diprifusor" TCI?
21. Q: What is the calorific value of Diprivan?
22. Q: What non-pharmaceutical methods have been used to reduce the incidence of pain on injection on induction of anaesthesia with propofol?
23. Q: Why is it necessary to shake a vial or ampuole of Diprivan before use?
1. Q: What pharmaceutical methods have been used to reduce the incidence of pain on injection on induction of anaesthesia with propofol?
A: A number of pharmaceutical methods have been used to reduce pain on injection including local anaesthetics (lignocaine, prilocaine, procaine alizapride and possibly EMLA cream), opioids (fentanyl, alfentanyl and pethidine), labetalol, metoclopramide,ketamine, nitroglycerine, aspirin and lipids. The most commonly used methods employ either lignocaine or the opioid analgesics.
Effects of local anaesthetics
Lignocaine (Lidocaine)
Gehan et al (AN18465) showed that lignocaine at a dose of 0.1 mg/kg or greater administered with 2.5mg/kg propofol at induction significantly reduced the incidence of pain on injection. Similar results have been demonstrated in a number of studies where lignocaine has either been mixed with propofol or administered separately. Stafford et al (AN18471), Newcombe (AN17350), Johnson et al (AN15320), Ewart and Whitwam (AN14678),Morton (AN13875), Goodrum et al (AN11927), Helbo-Hansen et al (AN9548) and Barker and Kamath (AN7173).
Prilocaine
1% prilocaine reduced propofol injection pain from 89% (saline control) to 69% (Eriksson AN34612)
Procaine
Nicol et al (AN19315) showed that there was no statistical difference between 2% procaine and 2% lignocaine in their ability to reduce propofol injection pain when administered through small peripheral veins.
EMLA
EMLA cream is a topical anaesthetic commonly used for the insertion of intravenous catheters and needles in children. The patients usually receive the EMLA Cream (2.5% lignocaine, 2.5% prilocaine) 1 h prior prior to surgery. It is not known what effect this has on the incidence of pain during induction of anaesthesia with Diprivan. However it would be predicted that EMLA would have some beneficial effect on the burning sensation produced by `Diprivan` around the site of injection.
Alizapride
1% lignocaine or 25mg alizapride (a benzamide derivative structurally related to procainamide with anti-emetic properties) administered immediately before propofol injection reduced propofol injection pain from 78%(placebo) to 18% and 56% respectively. The greater effect of lignocaine was statistically significant (Zaouk et al AN27473).
Effect of opioid analgesics
Fentanyl
2mcg/Kg fentanyl given intravenously immediately before propofol reduced propofol injection pain from 93% (Saline placebo) to 36% in 28 children (Chessa AN32441).
Alfentanil
Pre-treatment with 1mg alfentanil reduced pain on injection with propofol from 67% in the placebo saline group to 24%. Premixing `Diprivan` with 40 mg lignocaine reduced the incidence to 13%. (Nathanson et al AN40670). Fletcher et al (AN30457) showed that administration of 1 mg alfentanil 15 s before propofol reduced the incidence of propofol injection pain from 84% to 36%. In contrast Dru et al (AN24543) showed that there was no noticeable reduction in pain when alfentanil was given intravenously just before or after propofol but when it was given 3 min before propofol pain was reduced. In addition Hiller and Saarnivaara (AN24063) showed that although 10-20 mcg alfentanil reduced propofol injection pain it was not as effective as 1% lignocaine.
Pethidine
Pretreatment with either 25 mg pethidine or 10 mg lignocaine reduced pain on injection with propofol from 64% in the placebo saline group to 35% and 44% in the pethidine and lignocaine groups respectively.(Lyons et al AN40473)
Effect of other drugs
Labetalol
10 mg labetalol was as effective as lignocaine, 20 mg, in reducing propofol induced pain on injection in 102 patients. 89% of patients receiving placebo saline experienced pain in contrast to 17% on labetalol and 13% on lignocaine (Khalid AN 41559).
Metoclopramide
20mg lignocaine and 10mg metoclopramide when administered intravenously after a rubber tourniquet for one minute reduced propofol injection pain from 67% in the placebo saline group to 10% and 15% respectively (Maroof et al AN35457). Mecklem (AN33333) showed that mixing propofol with 20mg metoclopramide was as effective as mixing propofol with 1% lignocaine in reducing propofol injection pain. Similar results were obtained by Ganta and Fee(AN24580)
Ketamine
20 mg ketamine injected while venous drainage was occluded for 1 min significantly reduced the incidence (and severity) of propofol injection site pain from 85% in the control group to 7%. No postoperative hallucinations were reported after ketamine (Khalid AN35329).
Nitroglycerine
A strip of ointment containing 5 mg nitroglycerine applied over the back of one hand 20 min prior to induction with propofol reduced propofol injection pain from 67% (placebo) to 36%. No patient had headache or postural hypotension (Wilkinson et al AN29819).
Aspirin
Aspirin