My passion, My profession--Anesthesiology: November 2010

EXTRA VASCULAR/SUBCUTANEOUS INJECTION:

Most I/V induction agents (and especially barbiturates because of their alkalinity) are irritant when injected extravascularly.
The extent of pain and damage depends upon the volume and concentration of the injection. These can vary from minor irritation and erythema to sever pain, tissue necrosis to sloughing
Pain can be elevated by infiltrating the area with 1% lignocaine (without vasoconstrictor), the penetration of which can be assisted by addition of hyaluronidase.
Vasodilation and comfort are aided by warm compressed and simple analgesics.

INTRA-ARTERIAL INJECTION:

This can lead to serious damage to the blood supply of the affected limb with permanent ischemic sequelae.
The consequences of intra-arterial injection of other drugs such as antibiotics can be just as disastrous as those of barbiturates
The classic response is immediate and agonizing pain shooting down the arm into hand and fingers. The severity is such that it is unlikely to be caused by any other event during induction
The pain may subsequently last for a short time, be persistent or return later, presumably because of attacks of vascular spasm.
After the pain, the limb blanches, the pulse disappears and the limb then becomes mottled and cyanosed.
An intense chemical arteritis develops and there may be crystal deposition in small vessel.

MANAGEMENT:

On suspicion, immediately stop the injection
Leave the needle or cannula in vein.
Into the artery inject lignocaine 100 mg and papavarine 40 mg in 10-20 ml of saline
Give 4000 IU heparin I/V (unless otherwise contraindicated or unless a sympathetic block is to be done immediately
Keep the limb warm to encourage vasodilation
Consider the sympathectomy by local anesthetic e.g. stellate ganglion block.
Long term management depends upon the extent of damage and may involve limb salvage surgery or plastic reconstruction

My passion, My profession--Anesthesiology