Perfusion
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During cardiopulmonary bypass, the perfusionist maintains physiological parameters laid down in protocols; this is his or her performance capability. In order to assess his or her performance we need to be able to analyse these physiological parameters objectively. We defined six parameters, pH, BE, PaCO2, PaO2, ACT and oesophageal temperature and gave them ideal values of 7.40+/-0.05, 0.0+/-2.5 mmol/l, 39.0+/-3.0 mmHg, 150+/-50 mmHg, 540+/-60 s and 37.2+/-0.2 degrees C, respectively. ⋯ We then analysed what percentage of our 100 patients fell within each score range for each of the six parameters. This is an efficient means in analysing whether the perfusionist abides by the protocols, what quality is supplied to the patient, does he or she react when he or she is faced with parameters that are out of range and finally advocating in-line blood gas monitoring. This is another step towards our goal of total quality management.
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An experiment to study the role of contact-activation leukocyte sequestration in the formation of ischaemia-reperfusion injury (I-R injury) was carried out. The study was conducted using light and electron microscopic analyses in an ovine cardiopulmonary bypass (CPB) model using a membrane oxygenator. Five adult sheep were used in the study. ⋯ Neither significant differences in the transpulmonary gradients of leukocytes nor a significant complement activation, expressed by C3a levels, was observed. The MDA level did not display a significant change related to lung reperfusion despite an increase in MDA after the start of CPB. These findings indicate that I-R injury during CPB may not be from complement-activation leukocyte sequestration, but from another source of oxygen free radicals related to CPB.
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Randomized Controlled Trial Clinical Trial
The effects of leucodepletion in patients who develop the systemic inflammatory response syndrome following cardiopulmonary bypass.
The development of the systemic inflammatory response syndrome (SIRS) is associated with increased morbidity and mortality. Numerous anticytokine trials have failed to demonstrate any outcome benefit and there has been little evidence of improvement in the prognosis of this condition over the past 20 years. This study examines the effect of using a white cell filter designed to remove polymorphonuclear cells (PMNs) in patients who developed SIRS 36 h after cardiopulmonary bypass (CPB). ⋯ Leucofiltration safely and effectively removes circulating PMNs from patients with SIRS following CPB. This may result in improved pulmonary and renal function in these patients. Further studies are required of the kinetics and phenotypic characteristics of PMN removal by leucofiltration and a larger multicentre study will be necessary to determine whether this novel therapy has a significant outcome benefit in critically ill patients with SIRS.
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Randomized Controlled Trial Clinical Trial
Systemic leukocyte filtration during cardiopulmonary bypass.
Cardiopulmonary bypass (CPB) induces a whole body inflammatory response leading to postoperative lung dysfunction. Activated leukocytes may play a role in the pathogenesis of pulmonary dysfunction. We evaluated postoperative lung function after the use of leukocyte-depleting filters incorporated in the extracorporeal circuit during CPB. ⋯ There was no difference in intubation time between the two groups (16.4 h for group C vs 11.2 h for group F). Pulmonary function tested by pulmonary respiratory index [RI = partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2 x 100)] did not show significant difference between the two groups, either arriving in the ICU (group C RI 265 vs group F RI 322), or after 3 h (group RI 304 vs group F RI 305) or after 6 h (group C RI 292 vs group F RI 319). Leukocyte-depleting filters reduce with blood cells count during CPB, but, in this study, WBC depletion did not significantly improve clinical conditions or laboratory finding.