Effect of Dexmedetomidine and Bupivacaine for Paravertebral Block

Fracture femur is a common injury which is associated with excruciating pain . This pain is one of the most important causes of postoperative morbidity and mortality when it is insufficiently treated pain. Pain induces neuroendocrine stress response causing problems like as reduction in vital capacity, pneumonia, tachycardia, hypertension, myocardial ischemia and even infarction. These problems can be prevented by successful management of postoperative pain.

In patients with proximal femoral fracture, the use of paravertebral blockade produces reliable level of analgesia without need for additional nursing skills or monitoring in the postoperative period. Paravertebral blockade by injection local anesthetic solution alongside the vertebral column produces ipsilateral analgesia.

Currently available local anesthetics as bupivacaine may not provide reliable periods of analgesia resulting in block resolution before the period of worst postoperative pain. The use of a large volume of local anesthetic is one of methods to overcome this problem that may lengthen the duration of analgesia but at increased risk of local anesthetic toxicity. Adding adjuvants is another potential alternative.

Dexmedetomidine, a selective α 2 agonist, has been used to prolong the duration of analgesia of nerve blocks. Dexmedetomidine has also been reported to enhance central and peripheral nerve blockade. Alpha adrenoceptors located at the nerve endings have a possible role in the analgesic mechanisms by preventing norepinephrine release. The spinal mechanism is the principle mechanism for the analgesic action of dexmedetomidine.