The Annals of thoracic surgery
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Warm continuous retrograde cardioplegia is thought to prevent myocardial ischemia. We tested this hypothesis by subjecting canine hearts to 2 hours of either antegrade or retrograde perfusion with normothermic blood cardioplegia. Ischemic alterations were evaluated through the measurement of myocardial pH, tissue levels of adenosine triphosphate and lactate, and the preservation of left ventricular contractility. ⋯ Tissue lactate levels rose to a significantly greater extent during retrograde perfusion and adenosine triphosphate levels declined, although not to a statistically significant degree. Finally, myocardial function, as assessed by the preload recruitable work area, was preserved (103% +/- 20% of baseline) in the antegrade group but was markedly diminished (33% +/- 6%) in retrogradely perfused left ventricles 35 minutes after the aortic cross-clamp was removed. These data suggest that ischemic metabolism and the subsequent alteration of myocardial function take place despite continuous retrograde perfusion with normothermic blood cardioplegia.
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Inadequate cerebral oxygenation during cardiopulmonary bypass may lead to postoperative cognitive dysfunction in patients undergoing cardiac operations. A psychological test battery was administered to 255 patients before cardiac operation and just before hospital discharge. Postoperative impairment was defined as a decline of more than one standard deviation in 20% of tests. ⋯ Factors correlated with jugular bulb saturation at normothermia were cerebral metabolic rate of oxygen consumption (r = -0.6; p < 0.0005), cerebral blood flow (r = 0.4; p < 0.0005), oxygen delivery (r = 0.4; p < 0.0005), and mean arterial pressure (r = 0.15; p < 0.05). Three measures were significantly related to desaturation at normothermia and at hypothermia as well: greater cerebral oxygen extraction, greater arterial-venous oxygen difference, and lower ratio of cerebral blood flow to arterial-venous oxygen difference. We conclude that cerebral venous desaturation occurs during cardiopulmonary bypass in 17% to 23% of people and is associated with impaired postoperative cognitive test performance.
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To evaluate the contribution of the respiratory pattern to the ventilatory response after lung transplantation, we studied the changes in minute ventilation, tidal volume, and respiratory rate during CO2 rebreathing in 14 patients with severe obstructive pulmonary disease, and compared them with 10 normal subjects. Seven patients underwent a bilateral lung transplantation and 7 patients had single-lung transplantation. Single-lung transplant recipients increased their respiratory rate by the last postoperative test compared with either preoperative or initial test periods (0.38 +/- 0.13 versus 0.027 +/- 0.24 or 0.12 +/- 0.08 breaths.min-1.mm Hg-1; p < 0.005). ⋯ The restored ventilatory response by the fourth postoperative week was due to a statistically significant increase in tidal volume for both single and bilateral lung transplant recipients. This study demonstrates that when lung transplant recipients have an appropriate ventilatory response to CO2 rebreathing, single-lung transplant recipients have a respiratory pattern similar to normal; whereas the bilateral lung transplant recipients show the effects of total pulmonary denervation. We conclude that the preserved ventilatory response in lung transplant recipients is composed of a respiratory pattern that is influenced by the presence or absence of vagal inputs.
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A new approach termed "fast-track recovery" ws undertaken at both the Baystate Medical Center and Hartford Hospital. The fast-track protocol involves the following principles: (1) preoperative education; (2) early extubation; (3) methylprednisolone sodium succinate before bypass followed by dexamethasone for 24 hours postoperatively; (4) prophylactic digitalization, metoclopramide HCl, docusate sodium, and ranitidine HCl; (5) accelerated rehabilitation; (6) early discharge; (7) a dedicated fast-track coordinator to perform both daily telephone contact and a 1-week postoperative examination; and (8) a routine 1-month postoperative visit with a PA or MD. To evaluate the effects of this approach on patient care, a retrospective 1-year analysis was undertaken in both institutions with all coronary artery bypass grafting patients compared in a consecutive manner before the origin of the fast-track protocol and subsequent to its beginning. ⋯ There was no increase in morbidity or mortality associated with the fast-track protocol either early or late. Thirty-day hospital readmission was not significantly different between the two groups. Fast-track methodology is effective, and we routinely employ this approach for all patients undergoing cardiopulmonary bypass.
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Video-assisted thoracoscopic technique was evaluated in 28 patients who underwent operation for massive pericardial effusion. Excellent results were obtained using this newly developed approach for inspection of all pericardial surfaces as well as pleural and pulmonary disorders. No perioperative or postoperative complications ensued. ⋯ From our experience, video-assisted thoracoscopy was a safe and effective procedure, especially for those patients with combined pericardial effusion and abnormal pulmonary or pleural pathology in whom subxiphoid pericardial window was not clearly diagnostic at the time of operation. It was effective also in the situation with recurrent or loculated pericardial effusion which allowed localization and drainage of it. We believe that the use of videothoracoscopy to visualize the whole pericardial and pleural cavity will continue to be of great benefit to patients with combined pericardial and pleural/lung diseases.