2. Antecubital Fossa + Intraarterial injection

triangular intermuscular depression on the anterior surface of the elbow joint base of the triangle is formed by the line which joins the medial and lateral epicondyles of the humerus The lateral side of the triangle is formed by the medial edge of the brachioradialis muscle, while the medial side is formed by the lateral border of the pronator teres The floor consists of the brachialis and supinator muscles. The roof (from above down) comprises skin, subcutaneous tissue and the deep fascia, which includes the bicipital aponeurosis.

Within the fossa lie the tendon of the biceps muscle and the terminal part of the brachial artery, which lies in the centre of the fossa prior to its division into the radial and ulnar arteries opposite the neck of the radius. It also contains the associated veins and the median and radial nerves.

Cephalic vein: this drains the radial side of the forearm, and ascends over the lateral side of the fossa to lie in a groove along the lateral edge of the biceps join the axillary vein @ pec major Basilic vein: this drains the ulnar side of the forearm and rises along the medial border of biceps to pierce the deep fascia in the middle upper arm before going on to form the axillary vein. Median cubital vein: this originates from the cephalic vein distal to the lateral epicondyle, and then runs upwards and medially across the antecubital fossa to join the basilic vein above the elbow.

One potential hazard is inadvertent puncture or injection into the brachial artery. The danger of this happening is lessened by the presence of the bicipital aponeurosis, which is an extension of the medial lower border of the muscle and tendon of biceps. The lateral cutaneous nerve of the forearm crosses the fascia of the roof of the fossa and, although it lies deep to the cephalic vein, may still be vulnerable to damage from a needle or cannula Long lines can be inserted via the antecubital veins, which offer a safer route to the central veins. Although cannulation at the elbow may be simple, the acute curve at the clavipectoral fascia may prevent a long venous catheter from gaining access to the central venous circulation.

intra-arterial catheter is mistaken for a venous cannula, when there is anomalous vascular anatomy such as an aberrant radial artery that can be mistaken for the cephalic vein at the wrist or when the arterial pulsation is so feeble in a hypotensive patient that the vessel is thought to be a vein. the awake patient, severe pain in the hand is a cardinal feature. In the anaesthetized or sedated patient, there may be ischaemic colour changes in the distal limb which, because of arterial spasm, may be pale, mottled or cyanosed. Thrombosis may follow. The degree of damage depends on the substance injected.

Thiopental causes substantial damage because at body pH it precipitates into crystals which occlude small arterial vessels and provoke intense vasospasm mediated via local noradrenaline release. In contrast, propofol does not cause the same problems and is relatively innocuous in comparison. Any such injection, however, should be treated as for the worst-case scenario, because clinical experience of intra-arterial injection of many drugs is limited.

arterial thrombosis and extremity ischaemia puts tissue at risk of necrosis, and so anti-coagulation is an important priority. Intravenous heparin 500–1,000 units would be a typical initial dose following which warm NaCl 0.9% can be infused in an attempt to dilute whatever substance has been injected into the artery. Arterial spasm can be treated with papaverine 40–80 mg Dexamethasone 8 mg given immediately may reduce arterial oedema. Perfusion can be enhanced by sympatholysis, either by a stellate ganglion block (which is quick to perform) or via a brachial plexus block using a catheter technique to provide continuous analgesia. Maintenance anticoagulation is recommended for up to 14 days, and hyperbaric oxygen has also been suggested as a means of minimizing final ischaemic damage.