Adrenaline in LA causes:
High-Yield Explanation
Ans: d (All of the above) Ref: KDT, 6th ed, p. 356; Bailey and Love, 24thed, p. 49* Addition of adrenaline (commonly 1:200000 to 1: 125000 concentration) to the local anaesthetic solution hastens the onset and prolongs the duration of action and permits a higher dose of drug to be used as it is more slowly absorbed into the circulation.* Duration of both sensory and motor blockade is increased by addition of epinephrine to lignocaine* Only sensory block is prolonged if epinephrine is added to bupivacaine with no effect on motor blockade.Contraindications for adrenaline with LAAbsoluteOther contraindicationsVasoconstrictor (adrenaline) should not be added for ring block of:* When other inhalational agents especially halothane which sensitizes myocardium to adrenaline* Myocardial ischemia patients* Hyperthyroid patients * Severe hypertensives* Intravenous regional anaesthesia * In patients taking either monoamine oxidase inhibitor or tricyclic antidepressant drug * Cardiac arrhythmia patients* Patients on beta blockersa. Handsb. Feetc. Fingersd. Toese. Penis (circumcision)f. PinnaNote. * Ropivacaine - Improved cardiovascular safety profile and provide relatively greater sensory th; motor blockade* Prilocaine- Presence of blue - brown skin colour indicates methaemoglobin toxicity* Bupivacaine - Has the highest local tissue irritancy, must never be injected into a vein and is absolutely contraindicated for use in intravenous regional anaesthesia