The Annals of thoracic surgery
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The etiology and incidence of neurologic injury occurring after cardiac operations employing cardiopulmonary bypass is reviewed. Results of studies demonstrating the role of microemboli generated by pump oxygenators, and evidence for the efficacy of arterial line filtration to decrease delivery of emboli into the cerebral circulation and to decrease postoperative neuropsychological dysfunction, are similarly reviewed. The impact of different strategies for management of pH during moderate hypothermic cardiopulmonary bypass on cerebral blood flow and coupling of cerebral flow and metabolism, as well as their impact on the incidence of postoperative cognitive dysfunction, are also discussed, along with the results of studies examining the efficacy of various agents including thiopental, nimodipine, and nafamostat to decrease cognitive dysfunction subsequent to bypass.
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Comparative Study Clinical Trial
Postoperative pain-related morbidity: video-assisted thoracic surgery versus thoracotomy.
One hundred thirty-eight consecutive, nonrandomized patients, with equivalent demographic and preoperative physiologic parameters, underwent either a video-assisted thoracic surgical (VATS) approach (n = 81) or a limited lateral thoracotomy (LLT) approach (n = 57) to accomplish pulmonary resection for peripheral lung lesions (< or = 3 cm in diameter). Wedge resection was done in 74 VATS patients and 19 LLT patients. Seven patients underwent VATS lobectomy and 38 patients had lobectomy performed through an LLT. ⋯ Shoulder girdle strength was equally impaired at day 3, but function was more improved in VATS patients at 3 weeks (p = 0.01). Patients undergoing wedge resection alone by LLT had greater impairment in early (day 3) pulmonary function (forced expiratory volume in 1 second) (p = 0.002); this difference from VATS was not sustained at 3 weeks. Video-assisted thoracic surgery is associated with reduced pain, shoulder dysfunction, and early pulmonary impairment compared with LLT for select patients requiring pulmonary resection.
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We describe a new noninvasive method using near-infrared spectroscopy for monitoring cerebral hemodynamics during cardiopulmonary bypass in children. All patients were undergoing open heart operations for repair of congenital heart defects. Standardized anesthesia, an alpha-stat method of blood gas management, and nonpulsatile flow were used in all cases. ⋯ During hypothermic bypass (25 degrees C), CBVR was significantly reduced to 0.05 +/- 0.02 mL x 100 g-1 x kPa-1. In addition, there were three values at mean arterial pressure of lower than 40 mm Hg in which CBVR was negative (-0.04 +/- 0.01 mL x 100 g-1 x kPa-1). We conclude that near-infrared spectroscopy is useful for the noninvasive investigation of cerebral hemodynamics during cardiopulmonary bypass.
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Comparative Study
Cerebral lactate release after circulatory arrest but not after low flow in pediatric heart operations.
Arteriovenous (jugular bulb) differences in blood lactate were followed throughout the procedure and until 18 hours postoperatively in 17 children undergoing congenital heart operations during profound hypothermia. Transcranial Doppler sonography was used to monitor changes in blood flow velocity in the middle cerebral artery. Ten children had a period of total circulatory arrest (39 +/- 6 minutes) during profound hypothermia (arrest group). ⋯ Differences in blood lactate level were significantly less than zero (p < 0.05) from the start of rewarming until 3 hours after the end of cardiopulmonary bypass in the arrest group, whereas differences in blood lactate level remained close to zero in the low-flow group. We conclude that circulatory arrest during profound hypothermia is followed by a period with release of lactate from the brain, indicating anaerobic cerebral metabolism and possibly disturbed cerebral aerobic metabolism. This study argues for the avoidance of circulatory arrest whenever possible.
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We investigated the effects of pulsatile flow for retrograde cerebral perfusion under profound hypothermia. Total cardiopulmonary bypass was carried out in adult mongrel dogs to induce hypothermia. One hour of total circulatory arrest was then performed at 20 degrees C in the control group of 6 dogs. ⋯ As for cerebral flow and adenosine triphosphate content, no significant differences could be found between the groups perfused retrogradely with pulsatile or with non-pulsatile flow. Values were always higher, nonetheless, in the groups perfused with pulsatile flow. We conclude that retrograde cerebral perfusion with pulsatile flow, when used under conditions of profound hypothermia, possesses more cerebroprotective effects than does non-pulsatile perfusion or circulatory arrest.