Local infiltration

Lignocaine 0.5-2% is often used but it is effective in more dilute solution. The effect is prolonged if it is given in adrenaline solution, up to 1 in 200 000, which causes vasoconstriction and also reduces bleeding. No more than 3 mg/kg body weight should be used, except when given with adrenaline, in which case up to 7 mg/kg body weight may be given. However, adrenaline must be avoided if the local blood supply is prejudiced. Lignocaine anaesthesia lasts up to 90 min. This may be extended by adding 0.25% bupivacaine to 0.5% lignocaine.

If the operation site is painful or tender, a bleb is first raised in normal skin a short distance away, such as 1 cm. The needle is inserted and anaesthetic gently injected as the tender area is approached. The local anaesthetic spreads ahead of the needle. Initially the solution is infiltrated superficially to produce a wheal along the line of the proposed incision.

If the exposure is deepened, infiltration is taken progressively deeper to create a field block. The injection is given slowly to avoid pain caused by hydrostatic pressure. Each time the needle is in a new area, aspiration is performed to guard against intravenous injection. It is often wise to inject deeper progressively as the operation proceeds, rather than attempt a complete field block at the beginning.

Figure 6.1. Blocking digital nerves in the web space to avoid raising tissue tension.

Local infiltration of anaesthetic agent is commonly used to enable the manipulation of fractures. Perhaps the commonest such use is for setting recently acquired Colles' fracture of the wrist. The level of the fractured radius is identified and infiltration of the fracture haematoma with 10-15 ml of plain, 1% lignocaine can begin. After 10 min, the fracture may be reduced.

The amount of anaesthetic agent used should be checked constantly to ensure the maximum amount has not been exceeded. The patient should be asked to report pain or untoward symptoms and signs of cerebral toxity such as drowsiness and slurred speech, and myocardial depression, such as slowing or irregularity of the pulse, should be closely monitored.

Sufficient time (5-10 min for lignocaine and up to 20 min for bupivacaine) should be allowed for the anaesthetic to act before starting the operation. It should be explained to the patient that touch sensation remains after pain sensation has been abolished, but discomfort or pain should be reported as soon as it is felt. Additional anaesthetic should be retained to use if there is discomfort.

11 Habits To Make or Break For Soft Flawless Skin

11 Habits To Make or Break For Soft Flawless Skin

Habits to Break and Habits to Maintain for Dazzling Skin. As you all know, our skin is the obvious appearance of who or what we are, or perhaps would like to be. However, it is more than just a simple mask.

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