In: COPD3 May 2014
Intraoperatively, there are factors related to the conduct of the operation and the pathophysiologic state of CPB that directly and indirectly impact on pulmonary function. The pump itself, for example, has been implicated in postoperative respiratory dysfunction. Roller-head pumps and centrifugal pumps both cause blood trauma that results in the liberation of vasoactive substances that have deleterious pulmonary and systemic effects. In addition, the sequestration of leukocytes and the effects of platelets in the lungs are other contributing causes of postoperative complications. The use of leukocyte filters and ultrafiltration during CPB remains controversial in the prevention of these problems. The oxygenators, perhaps the most important culprit in postoperative pulmonary dysfunction from the equipment standpoint, come in two varieties: bubble and membrane. Although there is little difference when the CPB time is short, membrane oxygenators cause less problems when CPB times are between 2 and 3 h. At our institution, we use roller-head pumps and membrane oxygenators and could not observe an appreciable difference in outcome compared with our affiliate hospital in which centrifugal pumps and membrane oxygenators are utilized. Finally, the issue of ITA graft as a contributing factor in postoperative respiratory disability has been described. Several authors have argued that takedown of the ITA, opening of the pleura, and placement of a thoracostomy tubes all contribute to postoperative discomfort which, in COPD patients, translates into worse pulmonary function. Others have not found this to be the case. Although we did not directly compare COPD patients with ITA grafts and those without, it is our impression that this was not a major factor. Rather, we were more concerned with avoiding injury to the phrenic nerve during ITA harvesting, since a paralyzed hemidiaphragm in a COPD patient can be disastrous. Thus, we avoid ice slush in the pericardium and take particular care during dissection of the ITA at the subclavian artery where the phrenic nerve is vulnerable. generic amaryl
Blog invites submissions of review articles, reports on clinical techniques, case reports, conference summaries, and articles of opinion pertinent to the control of pain and anxiety in dentistry.