Anaesthesia for extremity injuries

*notes taken from local master student program

Overview

· Extremity injuries can be life-threatening because of associated vascular injuries and secondary infectious complications.

Problems

Hemorrhage

· Vascular injuries can lead to massive hemorrhage and threaten extremity viability.

· For example, a femoral fracture can be associated with 2–3 units of occult blood loss, and closed pelvic fractures can cause even more occult blood loss resulting in hypovolemic shock.

· Delay of treatment or indiscriminate positioning can worsen dislocations and further compromise neurovascular bundles.

Fat emboli

· Fat emboli are associated with pelvic and long-bone fractures and may cause pulmonary insufficiency, dysrhythmias, skin petechiae, and mental deterioration within 1–3 days after the traumatic event (see Chapter 40).

· The laboratory diagnosis of fat embolism depends on elevation of serum lipase, fat in the urine, and thrombocytopenia.

Compartment syndrome

· A compartment syndrome can also occur following large intramuscular hematomas, crush injuries, fractures, and amputation injuries.

· An increase in internal fascial pressure together with a reduced arterial pressure results in ischemia, tissue hypoxia, and progressive swelling.

Rhabdomyolysis and renal failure

· As previously discussed, rhabdomyolysis and renal failure may result.

· Reperfusion when blood pressure is restored can aggravate the injury and edema.

· The forearm and lower leg are most at risk.

· The diagnosis may be made clinically or based on direct measurement of compartment pressures: greater than 45 mm Hg or within 10–30 mm Hg of diastolic blood pressure.

· Early fasciotomy to save the limb is recommended.

· Modern surgical techniques frequently allow the reimplantation of severed extremities and digits (see Chapter 40).

· A cooled, amputated, limb part may be reimplanted up to 20 h following amputation; a noncooled part has to be implanted within 6 h.

· If the injury is isolated, a regional technique (eg, brachial or interscalene plexus block) is often recommended to increase peripheral blood flow by interrupting sympathetic innervation.

· During general anesthesia, the patient should be kept warm, and emergence shivering must be avoided to maximize perfusion.