Hanna D. Golab

Processing and transfusion of residual cardiopulmonary bypass volume: effects on haemostasis, complement activation, postoperative blood loss and transfusion volume.

The aim of this prospective randomized study was to compare the effects of the transfusion of unprocessed and cell saver-processed residual cardiopulmonary bypass (CPB) volume on haemostasis, complement activation, postoperative blood loss and transfusion requirements after elective cardiac surgery. Blood samples were taken at eight points in time, perioperatively. Haematological data, including haemoglobin, haematocrit and platelet counts as well as coagulation parameters, including activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen and the fibrinolytic parameter D-dimers, were measured from each blood sample. For the assessment of complement activation, the total complement CH50 was analysed. In addition, postoperative blood loss and transfusion requirements were measured during the first 24 hours, postoperatively. The results of the study showed impaired haemostasis after the transfusion of both unprocessed and processed CPB volume. No significant differences were found between the groups in the measured coagulation parameters. Nor was a significant difference found in the complement concentration. However, in patients trans-fused with unprocessed CPB volume, a significantly (p = 0.019) higher amount of blood loss was found, postoperatively. In the same group of patients, the number of units of allogeneic erythrocyte concentrate suspension transfused was also significantly (p = 0.023) higher during the first 24 hours, postoperatively, compared to the patients transfused with processed CPB blood. The number of units of fresh frozen plasma and platelet suspension transfused was not significantly different between the groups. In conclusion, processing CPB volume in combination with processing peroperative blood loss may result in reducing the volume of transfusion needed of allogeneic blood products.

Intraoperative cell salvage in infants undergoing elective cardiac surgery: a prospective trial

BACKGROUND For a long time intraoperative cell salvage was considered not to be applicable in paediatric patients due to technical limitations. Recently, new autotransfusion devices with small volume centrifugal bowls and dedicated paediatric systems allow efficient blood salvage in small children. The purpose of this prospective non-randomised study was to determine the impact of intraoperative cell salvage on postoperative allogeneic blood products transfusion in infant patients undergoing cardiac surgery with cardiopulmonary bypass. METHODS Two consecutive cohorts (122 patients) were studied. The first cohort underwent procedures between January 2004 and July 2005 with only blood salvage from the residual volume. The second cohort consisted of patients operated on from August 2005 to December 2006, with additional use of intraoperative cell salvage. The following variables were analysed: peri- and postoperative blood loss, transfusion of homologous blood products and cell salvage product, haematological and coagulation data, measured before, during and after the operation. RESULTS Additional intraoperative cell salvage significantly enhanced the amount of cell saving product available for transfusion (183+/-56 ml vs 152+/-57 ml, p=0.003) and significantly more patients in this group received the cell saving product postoperatively. Consequently, allogeneic blood transfusion was significantly reduced in volume as well as in frequency. We did not observe any adverse effects of intraoperative cell salvage. CONCLUSION Intraoperative cell salvage, employed as an adjuvant technique to the residual volume salvage in infants undergoing first time cardiac surgery with cardiopulmonary bypass, was a safe and effective method to reduce postoperative allogeneic blood transfusion. Considering current cell salvage related expense and the cost reduction achieved by diminished allogeneic transfusion, intraoperative cell salvage in infants demonstrated no economic benefit.

Specific requirements for bloodless cardiopulmonary bypass in neonates and infants; a review

A miniaturized cardiopulmonary bypass circuit enables the safe performance, in selected pediatric patients, of bloodless open heart surgery. As the latest survival rates in neonatal and infant cardiac surgery have become satisfactory, investigators have concentrated upon the improvement of existing procedures. Institutional guidelines and multidisciplinary efforts undertaken in the pre- and postoperative periods are of great importance, concerning bloodless CPB and should be seriously pursued by all involved caregivers. This review reflects upon the selective, most relevant requirements for success of asanguinous neonatal and infant CPB: acceptable level of hemodilution during the CPB, patient preoperative hematocrit value and volume of CPB circuit. We present an assessment of practical measures that were also adapted in our institution to achieve an asanguinous CPB for neonatal and infant patients.

Small, smaller, smallest. Steps towards bloodless neonatal and infant cardiopulmonary bypass

In open heart surgery in neonates and small children, the cardiopulmonary bypass circuit surface and the priming volume are relatively large in relation to patient size and blood volume. Therefore, the use of allogeneic blood is inevitable to maintain the optimal hematocrit level during bypass. To avoid the deleterious effects of blood transfusion, as well as to reduce the contact surface of blood with artificial materials, we stepwise reduced the bypass circuit size. Use of the commercially available minimized elements and an adjusted set-up of the system allowed us to reduce usage of allogeneic blood in the prime and during the bypass. However, other supplemental measures are needed to obtain asanguineous cardiopulmonary bypass for neonatal and infant patients.

Risk factors for low colloid osmotic pressure during infant cardiopulmonary bypass with a colloidal prime

Extensive variations of colloid osmotic pressure (COP) measured in the priming as well as during infant cardiopulmonary bypass motivated us to audit clinical and laboratory data to identify the risk factors for low COP at the end of bypass. Data of 73 consecutive infant patients with body weight <10 kg, who underwent elective, first time open-heart surgery between March 2005 and December 2006 were examined. The following variables were analyzed: COP, blood loss, transfusion requirements and hematological data. Univariate and multivariate analysis of risk factors for low COP (<15 mmHg) was performed. Forty-eight percent of patients had COP <15 mmHg at the end of bypass. Those patients had significantly lower COP before start of bypass, during, and at the end of the operation. Significant univariate predictors of low COP at the end of bypass were: lower patient weight; lower COP before start of bypass, lower priming COP and larger volume of cardioplegia received into the circulation. After multivariable analysis, lower patient COP before bypass remained the only significant predictor for low COP at the end of bypass. Pre-bypass crystalloid dilution during induction should be avoided, as this is the most important cause of low COP during the bypass. Priming COP and COP management strategy should be adapted to the individual patient demand.

Washing of irradiated red blood cells in paediatric cardiopulmonary bypass: is it clinically useful? A retrospective audit

OBJECTIVE Despite the introduction of smaller cardiopulmonary bypass (CPB) circuits for paediatrics, it is frequently necessary to add irradiated red blood cell concentrate (IRBC) to maintain adequate haemoglobin levels and the oxygen carrying capacity. Irradiation of blood weakens the cell membranes and results in an increase of lactate and potassium concentration. In addition, prolonged shelf time of IRBC may enhance its lactate level. To avoid the adverse effects of increased lactate and potassium concentration during paediatric bypass, prewashing of homologous blood in a cell-saving device was implemented at our institution. A retrospective audit of clinical data was performed to assess the relevance of this method. METHODS Preceding the introduction of the blood pre-washing, we investigated 14 units of IRBC for lactate, potassium levels and shelf time. Afterwards, we evaluated the CPB and laboratory data from 69 patients with body weight <10 kg and the lactate levels in the priming of the bypass circuit. RESULTS The shelf time of blood units was 7.6 ± 2.7 days (minimum 5, maximum 14 days) with lactate concentration of 12.6 ± 2 mmol/land potassium concentration of 16.2 ± 4.7 mmol/l. In the priming after pre-washing, the lactate concentration was significantly lower than the standard priming (2.5 ± 0.9 vs 4.5 ± 20 mmol/l, p = 0.002). At the start of bypass, the lactate concentration after pre-washing was still lower (1.5 ± 0.4 vs 1.9 ± 0.9 mmol/l; p = 0.04), but at the end of bypass we detected a significant increase of lactate in the pre-washed group (1.5 ± 0.4 vs 2.2 ± 1.1 mmol/l, p = 0.01). There was no significant difference between the groups at the end of bypass (1.8 ± 0.9 vs 2.2. ± 1.1 mmol/l, p = 0.17). Other clinical and patient data were not significantly different. CONCLUSIONS Our retrospective audit shows that pre-washing of IRBCs is not associated with decreased lactate levels at the end of CPB compared with standard use of IRBCs, suggesting that the added value of pre-washing of IRBCs on minimisation of lactate levels during CPB remains doubtful.

Does pharmacotherapy influence the inflammatory responses during cardiopulmonary bypass in children

Abstract: Cardiopulmonary bypass (CPB) induces a systemic inflammatory response syndrome (SIRS) by factors such as contact of the blood with the foreign surface of the extracorporeal circuit, hypothermia, reduction of pulmonary blood flow during CPB and endotoxemia. SIRS is maintained in the postoperative phase, co-occurring with a counter anti-inflammatory response syndrome. Research on the effects of drugs administered before the surgery, especially in the induction phase of anesthesia, as well as drugs used during extracorporeal circulation, has revealed that they greatly influence these postoperative inflammatory responses. A better understanding of these processes may not only improve postoperative recovery but also enable tailor-made pharmacotherapy, with both health and economic benefits. In this review, we describe the pathophysiology of SIRS and counter anti-inflammatory response syndrome in the light of CPB in children and the influence of drugs used on these syndromes.

The influence of oxygen delivery during cardiopulmonary bypass on the incidence of delirium in CABG patients; a retrospective study

Introduction: Postoperative delirium is the most common neurological complication of cardiac surgery. Hypoxia has been shown to increase the risk of postoperative delirium. The possibility to continuously monitor oxygen delivery (DO2) during cardiopulmonary bypass (CPB) offers an adequate approximation of the oxygen status in a patient. This study investigates the role of oxygen delivery during cardiopulmonary bypass in the incidence of postoperative delirium. Methods: Three hundred and fifty-seven adult patients who underwent normothermic coronary artery bypass grafting (CABG) surgery were included in this retrospective study. The nadir indexed DO2 (DO2i) value on bypass, the total time under the critical DO2i level and the area under the curve (AUC) for critical DO2i were determined. Delirium was identified by the postoperative administration of haloperidol. Results: The mean nadir DO2i significantly differed, comparing the group of patients with postoperative delirium to the group without. Multivariate analysis only identified age, pre-existing cognitive impairment, preoperative kidney dysfunction and cross-clamp time as independent risk factors for delirium. The results also indicated that patients of older age were more sensitive to a declined DO2i. Conclusion: A low DO2i during cardiopulmonary bypass is significantly associated with the incidence of postoperative delirium in CABG patients. However, the role of DO2 as an independent predictor of delirium could not be proven.

Clinical outcome and blood transfusion after infant cardiac surgery with a routine use of conventional ultrafiltration.

Objective Priming-related hemodilution is the culprit behind excessive body water accumulation, postoperative coagulopathy and enhanced blood transfusion in infant cardiac surgery patients. In this retrospective, observational study, clinical data were analyzed to assess the effect of conventional ultrafiltration on allogenic blood transfusion and patient clinical outcome. Methods All infants with a bodyweight up to 10 kg who underwent consequent cardiac surgery in 2011 and 2012 were eligible for the audit. Seventy patients, operated in accordance with existing pediatric protocol, enrolled in the control group. The study group consisted of 55 patients who were operated employing conventional ultrafiltration during bypass and recently adjusted hematocrit targets. The following variables were primarily investigated: hematocrit and colloid osmotic pressure value, total volume of blood products transfused and duration of postoperative mechanical ventilation. Secondary outcome measures were: postoperative urine production, postoperative blood loss, length of stay at the intensive care unit and hospital stay. Results There were no significant differences between the groups in relation to demographics or hematological and cardiopulmonary bypass data. The ultrafiltration volume removed from circulation during bypass in the study group was 171 ± 99 ml. No significant difference between the groups was found with regard to the total allogenic blood transfusion (study group 216 ± 92 ml versus control group 191 ±93 ml; p = 0.136). All recorded clinical end points, duration of mechanical ventilation, duration of chest tube in situ, stay in ICU and stay in hospital, were similar between the groups. Conclusions Routine use of conventional ultrafiltration during the cardiac surgery for patients with a bodyweight less than 10 kg was a safe technique that allowed us to achieve higher hematocrit levels at the end of the operation without additional transfusions of allogenic blood. On the other hand, ultrafiltration did not improve the clinical end points.