...DILUTION of 1:200,000 implies that 1 gm of the drug is dissolved in 200,000 ml of the total volume of the solution.
P.S. THEREFORE, 1 gm = 1,000 mg = 1,000,000 ug (microgram) dissolved in 200,000 ml solution. That is to say, 1,000,000 ug in 200,000 ml. Upon cancelling, 5 zeros from each, it is 10 ug in 2 ml i.e. 5 ug in 1 ml = 5 ug/ml. Now, it is quite understood that a drug having a dilution of 1:200,000 means that the drug is 5 ug/ml. In the ratio 1:200,000 the gm and ml are silent!
Generally, in ENT surgeries in order to induce vasoconstriction such that blood loss is minimal and the absorption of the local anaesthetic like lignocaine is slow and the anaesthetic effect of the local infiltrate into nasal septum or ear canal is prolonged, adrenaline is added to lignocaine in the dilution of 1:200,000.
In the available bottle of 2% lignocaine with ADR, adrenaline is generally 1:80,000. That is to say, 1 gm in 80,000 ml = 1,000,000 ug in 80,000 ml = 100 ug in 8 ml = 12.5 ug in 1 ml = 12.5ug/ml. In terms of percentage, it needs to be expressed as gm% = gm/100 ml. That is to say, 12.5 ug/ml = 1250 ug/100 ml = 1.25 mg/100 ml = 0.0125 gm/100 ml = 0.0125%.
Lignocaine with ADR can be given up to 7 mg/kg, whereas without ADR only 3 mg/kg because without ADR, lignocaine is absorbed faster into systemic circulation and can cause cerebral and cardiovascular toxicity.
When an operation is performed under general anaesthesia, only adrenaline infiltration can suffice for vasoconstriction and bloodless field. An ampoule of ADR contains 1 mg in 1 ml i.e. 1,000 ug in 1 ml = 1,000 ug/ml. Since, ADR is generally infiltrated in a dilution of 1:200,000 = 5 ug/ml, only 0.1 ml (100 ug) ADR from the ampoule needs to be added into 20 ml normal saline to achieve 5 ug/ml dilution = 1:200,000.
The 2% lignocaine implies that 2 gm of lignocaine is diluted in 100 (cent) ml of the solution = 2,000 mg in 100 ml = 20 mg in 1 ml = 20 mg/ml. By denoting as 2%, gm and 100 ml (cent) are missing. When 2% = 20 mg/ml, one needs to just shift the decimal point by one place to the right. For an example if 0.5% Bupivacaine plain is to be used for local infiltration, it implies 5 mg/ml, just shift the decimal point one place to the right to get mg per ml.
A drug like adrenaline is available in an ampoule 1 mg/ml, it can be expressed as 1:1000 because in 1000 ml would contain 1 gm of adrenaline. Similarly, in terms of percentage it can be said to be 0.1% because upon shifting the decimal point by one place, it becomes 1 mg/ml. Conversely, 1 mg in 1 ml = 1000mg in 1000 ml = 1 gm in 1000 ml = 0.1 gm in 100 ml = 0.1 gm in cent (100) ml = 0.1 gm%. = 0.1%.
The Solution to Dilution:
https://emergencypedia.com/2014/01/07/the-solution-to-dilution/
Lignocaine:
https://www.rxlist.com/xylocaine-drug.htm
Adrenaline:
http://www.empr.com/adrenalin/drug/40/
Local anaesthetics:
https://lifeinthefastlane.com/procedures/local-anaesthetic/
P.S. THEREFORE, 1 gm = 1,000 mg = 1,000,000 ug (microgram) dissolved in 200,000 ml solution. That is to say, 1,000,000 ug in 200,000 ml. Upon cancelling, 5 zeros from each, it is 10 ug in 2 ml i.e. 5 ug in 1 ml = 5 ug/ml. Now, it is quite understood that a drug having a dilution of 1:200,000 means that the drug is 5 ug/ml. In the ratio 1:200,000 the gm and ml are silent!
Generally, in ENT surgeries in order to induce vasoconstriction such that blood loss is minimal and the absorption of the local anaesthetic like lignocaine is slow and the anaesthetic effect of the local infiltrate into nasal septum or ear canal is prolonged, adrenaline is added to lignocaine in the dilution of 1:200,000.
In the available bottle of 2% lignocaine with ADR, adrenaline is generally 1:80,000. That is to say, 1 gm in 80,000 ml = 1,000,000 ug in 80,000 ml = 100 ug in 8 ml = 12.5 ug in 1 ml = 12.5ug/ml. In terms of percentage, it needs to be expressed as gm% = gm/100 ml. That is to say, 12.5 ug/ml = 1250 ug/100 ml = 1.25 mg/100 ml = 0.0125 gm/100 ml = 0.0125%.
Lignocaine with ADR can be given up to 7 mg/kg, whereas without ADR only 3 mg/kg because without ADR, lignocaine is absorbed faster into systemic circulation and can cause cerebral and cardiovascular toxicity.
When an operation is performed under general anaesthesia, only adrenaline infiltration can suffice for vasoconstriction and bloodless field. An ampoule of ADR contains 1 mg in 1 ml i.e. 1,000 ug in 1 ml = 1,000 ug/ml. Since, ADR is generally infiltrated in a dilution of 1:200,000 = 5 ug/ml, only 0.1 ml (100 ug) ADR from the ampoule needs to be added into 20 ml normal saline to achieve 5 ug/ml dilution = 1:200,000.
The 2% lignocaine implies that 2 gm of lignocaine is diluted in 100 (cent) ml of the solution = 2,000 mg in 100 ml = 20 mg in 1 ml = 20 mg/ml. By denoting as 2%, gm and 100 ml (cent) are missing. When 2% = 20 mg/ml, one needs to just shift the decimal point by one place to the right. For an example if 0.5% Bupivacaine plain is to be used for local infiltration, it implies 5 mg/ml, just shift the decimal point one place to the right to get mg per ml.
A drug like adrenaline is available in an ampoule 1 mg/ml, it can be expressed as 1:1000 because in 1000 ml would contain 1 gm of adrenaline. Similarly, in terms of percentage it can be said to be 0.1% because upon shifting the decimal point by one place, it becomes 1 mg/ml. Conversely, 1 mg in 1 ml = 1000mg in 1000 ml = 1 gm in 1000 ml = 0.1 gm in 100 ml = 0.1 gm in cent (100) ml = 0.1 gm%. = 0.1%.
The Solution to Dilution:
https://emergencypedia.com/2014/01/07/the-solution-to-dilution/
Lignocaine:
https://www.rxlist.com/xylocaine-drug.htm
Adrenaline:
http://www.empr.com/adrenalin/drug/40/
Local anaesthetics:
https://lifeinthefastlane.com/procedures/local-anaesthetic/
Comments
Post a Comment