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Intramuscular Injections. Injection of substance directly in muscle, for forms of medicine used delivered in small amounts. Indications: Where IV administration is not available. Drugs with specific actions on muscles. A longer half life is needed eg. Morphine for anaesthesia.
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Injection of substance directly in muscle, for forms of medicine used delivered in small amounts Indications: • Where IV administration is not available. • Drugs with specific actions on muscles. • A longer half life is needed eg. Morphine for anaesthesia
Complications & contraindications • Damage to the sciatic nerve. (Upper outer quadrant) • Injection fibrosis - causes inability to flex muscle drug is administered to. • Thrombocytopenia (low platelets) and coagulopathy (bleeding) can lead to hematomas. • Local sepsis • Arterial/IV injection • Infection
Method • Check identity of patient and contents and expiry date of drugs • Insert needle into syringe, and fill with the required amount of drug. Tap syringe to bring any air bubbles to the top and push the air out. • Choose a suitable injection site and inspect for signs of inflammation, swelling, infections or lesions • 5 main sites: • Upper arm (deltoid) – vaccines • Dorsogluteal (gluteus maximus) • Ventrogluteal(gluteus medius) • Vastus lateralis (quadriceps femoris) outer side of femur • Rectus femoris (anterior quadriceps) – self administration or infants
Method continued... • Swab site with alcohol and let it dry (bactericidal and decreases pain) • Pull skin laterally and insert needle in one swift motion at 90°, aspirate to avoid an intravenous placement, if blood is drawn in, restart with new medication and slowly inject the drug. • Remove needle and apply a pressure gauze and observe for signs of an adverse reaction. Moving the skin may distract from the intended needle destination, therefore visualise and aim for the underlying muscle about to receive the injection. http://www.youtube.com/watch?v=nA8i9eYW0_M
Injection of substance into the subcutaneous tissue – layer of skin directly below the dermis and epidermis. Indications • When drug is desired to have a slow, sustained absorption effect • Local anaesthesia • Administration of vaccines and medicines such as insulin and morphine
Complications & Contraindications • Avoid using the same site repetitively which can cause lumps or dents (lypodystrophies – loss or degeneration of fat) from forming. • Accidental IV, ID, IM injections
Method • Check identity of patient and contents and expiry date of drugs • Insert needle into syringe, and fill with the required amount of drug. Tap syringe to bring any air bubbles to the top and push the air out. • Choose a suitable injection site and inspect for signs of inflammation, swelling, infections or lesions • 4 main sites: • Upper arm outer area • Abdomen – above and below waist, except around navel • Anterior thigh – midway of outer side • Upper area of butt – behind hip bone
Method continued ... • When repeated injections are needed use a hidden site to cover bruises – but the same area at the same time each day to reduce changes in the action of the insulin • Swab site with alcohol and let it dry (bactericidal and decreases pain) • Gently pinch skin to elevate subcutaneous fat and separate it from underlying muscle. • Insert the needle at a 30° angle and inject the drug – aspiration before injecting the drug is unnecessary as can increase the risk of local hematoma formation for heparin. http://www.youtube.com/watch?v=bxdYGXKz1iA
Used when performing invasive medical procedures except in life saving procedures. Contraindications • Patient refusal – but many can be persuaded • Allergy – rare • DO NOT USE adrenaline containing LA on digits or penis – vasoconstriction can lead to ischaemia and necrosis. • Anticoagulated patients have a tendency to bleed if a vessel is punctured. • Infection at intended site may make it more painful and spread. • Broken needles • Acute systemic toxicity – CNS, CVS – when plasma conc., exceeds toxic limit.
Mechanism of action • LA block fast sodium channels in nerve axons preventing propagation of nerve impulse • Pain nerves are usually smaller and non myelinated fibres so are blocked faster than larger myelinated fibres (motor, proprioception, touch)
Parenteral LA • Injected subcutaneously • Onset of effect is 2 minutes, but duration varies depending on the drug. • LA solutions are alkaline pH 10/11 therefore are more painful • A less painful approach would be ID (instant anaesthesia) • Avoid intra vascular injection, so aspirate first.
