Pain after Cardiac Surgery

Most cardiac operations are performed via median sternotomy and cardiopulmonary bypass. Both thoracic incision and cardiopulmonary bypass cause major disturbances in the homeostasis of the patient. Disruption of the tissues by the incision initiates an immediate neurological reaction perceived as pain and an intense biochemical and cellular response to repair the wound. Cardiopulmonary bypass causes far more serious systemic changes in homeostasis than pain, and that is probably the main reason why cardiac surgery is behind other surgical specialties in the development of minimally invasive procedures. Pain associated with surgical incision is largely self-limited and resolves with time and, luckily, so do the changes caused by cardiopulmonary bypass. Obviously, surgical incisions that cause less tissue damage are associated with lower degrees of pain and metabolic disturbance than larger and more traumatic incisions.

In this issue of the International Journal of Cardiovascular Sciences, Silva and colleagues, from the University of Fortaleza, Brazil, report a comparative study on postoperative pain following conventional median sternotomy and right mini-thoracotomy. The study has limitations because of the sample size (there were only 17 patients in each arm), the endpoint of the study was largely subjective, and patients were not randomized. However, as one would expect, both groups of patients complained of pain in the first three days but fewer patients with mini-thoracotomy complained of pain by the seventh postoperative day. In addition, mini-thoracotomy was associated with pain of lower intensity, fewer sites, and shorter duration than median sternotomy.

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