Texas Heart Institute journal
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Early mobilization and aggressive physical therapy are essential in patients who receive left ventricular assist devices (LVADs) due to long-term, end-stage heart failure. Some of these patients remain ventilator dependent for quite some time after device implantation. We report our regimen of mobilization with the aid of a portable ventilator, in patients with cardiac cachexia and LVAD implantation. ⋯ There were significant functional gains during the period of prolonged mechanical ventilation. The patient was able to walk up to 600 feet by the time he was weaned from the ventilator and transferred out of the intensive care unit. He underwent successful heart transplantation 6 weeks after being weaned from the ventilator We believe that improving the mobility of LVAD patients who require mechanical ventilation has the potential both to facilitate ventilator weaning and to improve the outcomes of transplantation.
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Randomized Controlled Trial Comparative Study
Myocardial injury in coronary artery bypass grafting: On-pump versus off-pump comparison by measuring heart-type fatty-acid-binding protein release.
This prospective study uses heart-type fatty-acid-binding protein (hFABP) and creatine kinase-MB (CK-MB) release to compare myocardial injury in on-pump versus off-pump coronary artery bypass grafting (CABG). Fifty patients were randomly assigned to on-pump or off-pump CABG. The hFABP and CK-MB concentrations were measured in serial venous blood samples drawn before heparinization in both groups and after aortic unclamping at 1, 2, 4, 8, 24, 48, and 72 hours in the on-pump group. ⋯ In all patients, hFABP levels peaked as early as 1 hour after declamping (on-pump group) or 2 hours after the last distal anastomosis (off-pump group), whereas CK-MB peaked only at 4 hours after declamping (on-pump group) or 24 hours after the last distal anastomosis (off-pump group). The lower release of hFABP and CK-MB in the off-pump CABG group indicates that on-pump CABG with cardioplegic arrest causes more myocardial damage than does off-pump CABG. Heart-type fatty-acid-binding protein is a more rapid marker of perioperative myocardial damage, peaks earlier than CK-MB, and may predict the requirement for intensive monitoring for postoperative myocardial infarction.
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Randomized Controlled Trial Comparative Study
Continuous insulin infusion improves postoperative glucose control in patients with diabetes mellitus undergoing coronary artery bypass surgery.
Postoperative glucose control directly affects the incidence of deep sternal wound infection and death after patients with diabetes have undergone coronary artery bypass grafting. We compared the effect upon glucose control of continuous insulin infusion with that of glucometer-guided insulin injection after coronary artery bypass. Our prospective, randomized, controlled study involved patients with diabetes mellitus who underwent coronary artery bypass grafting in our hospital from January 2001 through January 2003. ⋯ Satisfactory blood glucose levels were achieved in significantly more patients undergoing infusion than injection (64.7% vs 28.6%, P <0.001). In the injection group, significantly more blood glucose measurements were required to achieve control (23.4 vs 16.5, P=0.001), and good control was attained much sooner in the infusion group (21.4 vs 30.5 hr, P=0.013). We conclude that continuous insulin infusion provides better control of postoperative blood glucose levels after coronary artery bypass grafting in patients with diabetes than does glucometer-guided insulin injection.
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There is an interest in the use of high thoracic epidural anesthesia in cardiac surgery, because experimental and clinical studies have suggested that central neuroaxial blockade attenuates the response to surgical stress and improves myocardial metabolism and perioperative analgesia-thus enabling earlier extubation and a smoother postoperative course. Matters of major concern in the adoption of high thoracic epidural anesthesia in cardiac surgery are neurologic injury secondary to neuroaxial hematoma and hypotension secondary to sympatholysis. The risk associated with possible neuraxial hematoma caused by high thoracic epidural anesthesia has been thoroughly investigated and largely discounted, but scant attention has been devoted to the onset of hypotensive episodes in the same setting. ⋯ Among the patient variables that we tested in a multivariate logistic-regression model, only female sex was found to be significantly correlated with hypotension. In order to decrease the incidence and severity of hypotensive episodes resulting from anesthetic blockade, anesthesiologists need to monitor, with special care, women patients who are under high thoracic epidural anesthesia. Further studies are needed in order to determine why women undergoing open heart surgery under high thoracic epidural anesthesia are at a relatively greater risk of hypotension.
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In order to determine the temporal pattern of weaning from mechanical ventilation for patients undergoing prolonged mechanical ventilation after cardiac surgery, we performed a retrospective review of 21 patients' weaning courses at our long-term acute care hospital. Using multiple regression analysis of an estimate of individual patients' percentage of mechanical ventilator support per day (%MVSD), we determined that 14 of 21 patients (67%) showed a statistically significant quadratic or cubic relationship between time and % MVSD. These patients showed little or no improvement in their ventilator dependence until a point in time when, abruptly, they began to make rapid progress (a "wean turning point"), after which they progressed to discontinuation of mechanical ventilation in a relatively short period of time. ⋯ Most patients in the study group weaned from the ventilator through a specific temporal pattern that is newly described herein. Data analysis suggested that the mechanism for the development of a wean turning point was improvement of pulmonary mechanics rather than improvement in gas exchange or respiratory load. Although these observations need to be confirmed by a prospective trial, they may have implications for weaning cardiac surgery patients from prolonged mechanical ventilation, and possibly for weaning a broader group of patients who require prolonged mechanical ventilation.