Blood transfusion during versus after cardiopulmonary bypass is associated with postoperative morbidity in neonates undergoing cardiac surgery.

INTRODUCTION: Cardiac surgery on neonates for the correction of congenital heart defects is usually associated with the transfusion of packed red blood cells (PRBCs) into the cardiopulmonary bypass (CPB) circuit. We hypothesised that such transfusions of stored PRBCs directly into the arterial system may increase postoperative morbidity when compared to intravenous transfusion. PATIENTS AND METHODS: In this retrospective cohort study, data from 122 consecutive neonates who received transfusions of PRBCs in the course of corrective surgery for congenital heart defects were analysed. Group assignment was according to the timing of the first transfusion: during CPB (On-CPB) or after weaning from CPB (Post-CPB). Chi Square and rank sum tests were applied to compare clinical characteristics. Times until extubation and release from the intensive care unit were analysed by Kaplan-Meier curves and by multivariate Cox regression. RESULTS: Transfusion of PRBCs during CPB was associated with greater 48 hour blood loss (mean±standard deviation, 86±125 versus 32±16 mL/kg, p<0.001), longer duration of mechanical ventilation (214±268 versus 99±75 h, p<0.001) and longer stay on the intensive care unit (10.9±12.1 versus 5.3±3.5 days, p<0.001). However, the groups also differed in many characteristics, such as bodyweight, complexity of surgery or preoperative haemoglobin concentration, which may also affect outcome. Yet, multivariate analyses confirmed an independent association of transfusion On-CPB with an adverse clinical outcome. CONCLUSIONS: Our results are consistent with the hypothesis that the transfusion of PRBCs during CPB may increase postoperative morbidity. However, due to the limitations of this retrospective analysis, further studies are needed to confirm a causal relationship between the timing of the transfusion and the clinical outcome and to elucidate putative mechanisms of such an association.

Circulatory arrest and renal function in open-heart surgery on infants.

This study was designed to evaluate the impact of circulatory arrest on renal function in open-heart surgery on infants. Renal function was described by diuresis, urine/plasma creatinine ratio, creatinine clearance, urinary albumin, and N-acetyl-beta-D-glucosaminidase measurements. Seven patients who underwent circulatory arrest (group 1) were compared with 37 patients operated on with cardiopulmonary bypass without circulatory arrest (group 2). In group 1, bypass time was 164 minutes and the lowest body temperature was 25.6 degrees C (median), compared with 106 minutes and 31.3 degrees C in group 2 (p < 0.05). Although diuresis and creatinine clearance revealed no differences between the groups, urine measurements, which had normal values before cardiopulmonary bypass, increased during reperfusion to 58.6 (range 16.2-75.5) mg gCrea(-1) albumin and to 14.8 (range 1.6-21.8) U gCrea(-1) N-acetyl-beta-D-glucosaminidase in group 1, compared with 8.1 (range 0-127.7) mg gCrea(-1) and 1.9 (range 0-47.8) U gCrea(-1) in group 2 (p < 0.05). Thus, deep hypothermic circulatory arrest (DHCA) subjected the kidney to ischemia reperfusion injury. Although the findings are mild and do not indicate severe ischemic renal damage, potential renal damage by DHCA should be taken into account when planning surgical procedures for congenital heart disease patients with additional risks of acute renal failure.

Hemorheology and renal function during cardiopulmonary bypass in infants.

BACKGROUND: Acute renal failure is an occasional complication after cardiopulmonary bypass in infants. Whereas it is well known that postoperative hemodynamics inflict acute renal failure, the influence of extracorporeal circulation on the kidney is less clear. Moreover, changes in blood viscosity occur during and after surgery, which may influence renal dysfunction. For this reason, we investigated the impact of blood viscosity on renal function during cardiopulmonary bypass. METHODS: In 34 patients weighting less than 10 kg, we performed repeated analysis of urine, blood, and plasma viscosity. RESULTS: Polyuria and proteinuria that appeared during cardiopulmonary bypass indicated an elevated transglomerular filtration gradient, which recovered within 24 hours. The appearance of N-acetyl-beta-D-glucosaminidase in the urine, and elevated excretion of sodium, were additionally indicative of mild tubular damage. Elevation of blood viscosity during hypothermic perfusion showed a statistical correlation with proteinuria and N-acetyl-beta-D-glucosaminidaseuria. With hypothermia, the relation of blood viscosity to plasma viscosity became stronger, while the relation to the hematocrit decreased compared to normothermia. CONCLUSIONS: During cardiopulmonary bypass perfusion, the kidney can be stressed by proteinuria and mild tubular damage. Our data provide evidence that the kidneys can be protected by improved blood viscosity during cardioplegia, but this needs confirmation in a prospective interventional study.

Dynamic changes in cerebral oxygenation related to deep hypothermia and circulatory arrest evaluated by near-infrared spectroscopy.

BACKGROUND: Total circulatory arrest in deep hypothermia, which is used in corrective surgery of complex cardiovascular malformations, has been said to cause brain injury. Near-infrared spectroscopy (NIRS) is a new non-invasive method that potentially monitors changes in cerebral oxygenation and tissue oxygen utilisation. The aim of this experimental study in rabbits was to evaluate the change in intravascular and intracellular oxygenation patterns during cooling, deep hypothermic circulatory arrest and rewarming using a commercially available NIRS-cerebral oximeter. METHODS: Ten New Zealand White male rabbits (weight, 3.1+/-0.25 kg BW) were included in this study. All animals underwent cardiopulmonary bypass (CPB), cooling to a rectal temperature below 15 degrees C, 60 min of deep hypothermic circulatory arrest (DHCA) followed by reperfusion and rewarming. Cerebral oxyhaemoglobin (HbO2), deoxyhaemoglobin (HHb) and cytochrome oxidase aa3 (CytOxaa3) concentrations were continuously measured during the entire procedure using the Cerebral RedOx Monitor 2020 (Criticon cerebral redox monitor 2020, Johnson & Johnson Medical). Total haemoglobin concentration (tHb) and regional cerebral oxygen saturation (rSO2) values were calculated by integrated algorithm. RESULTS: In all animals an initial increase of oxygenated haemoglobin (HbO2, rSO2) and a fall in deoxygenated haemoglobin (HHb) were found during cooling on bypass. A slight decrease in CytOxaa3 signal was observed in response to initial cooling. Variation in intravascular haemoglobin oxygenation parameters (HbO2, HHb) were related to haemodynamic changes associated with fluid loading, initiation and termination of CPB, bypass flow rate and cooling and rewarming. When the pump flow was stopped all NIRS parameters, except the HHb value, decreased precipitously during the DHCA-period (P<0.01). After reperfusion and rewarming, all haemoglobin oxygen saturation readings returned nearly to pre-CPB levels (P=0.09), but the CytOxaa3 was still significantly lower than the pre-CPB levels (P<0.05). CONCLUSION: The change in the NIRS-derived haemoglobin oxygenation parameters may reflect physiological changes in systemic and cerebral haemodynamics. CytOxaa3 values may represent related effects on cellular oxygenation. Thus, continuous, real-time NIRS-monitoring may identify critical periods with inadequate brain tissue oxygenation, particularly during DHCA. The neurological implications of the observed changes in NIRS oxygenation parameters, however, require further quantitative morphological evaluation of the brain in animals surviving a longer reperfusion and observation period.

Saving the world by teaching behavior analysis: a behavioral systems approach.

This article presents a behavioral systems approach to organizational design and applies that approach to the teaching of behavior analysis. This systems approach consists of three components: goal-directed systems design, behavioral systems engineering, and performance management. This systems approach is applied to the Education Board and Teaching Behavior Analysis Special Interest Group of the Association for Behavior Analysis, with a conclusion that we need to emphasize the recruitment of students and the placement and maintenance of alumni. This systems approach is also applied at the scale of the individual faculty member running a university-based training system and is seen to generate special approaches to textbook preparation, undergraduate research, colloquium and conference attendance, career counseling, preparation for graduate examinations, graduate training and graduate seminars, and classroom alternatives to the traditional lecture.

Total hip arthroplasties in the elderly. Morbidity, mortality, and cost effectiveness.

Forty-two patients older than 80 years were treated with hip arthroplasty from 1980 to 1986. Seventy-five percent experienced a complication. The most common complications were excessive bleeding, postoperative confusion, urinary tract infection, and dislocation. Hospital stay averaged 16 days and was more prolonged in 14 patients. There was one postoperative death. The survival time of the other 41 patients currently ranges from nine months to eight years. At this time, 50% are alive and functional at an average of five-years follow-up evaluation. Comparing the cost of hip arthroplasty to the cost of nursing home placement, the procedure is clearly cost effective.

Classification and management of acetabular abnormalities in total hip arthroplasty.

Total hip arthroplasty, for both primary and revision operations, frequently involves bony abnormalities of the acetabulum. No standard nomenclature currently exists for the definition of acetabular deficiencies. A classification system is presented to assist in the preoperative evaluation and to provide a treatment protocol for these defects.

Mycotic aneurysm of the external iliac artery caused by migration of a total hip prosthesis.

A 77-year-old patient had a mycotic aneurysm of the left external iliac artery secondary to migration of a total hip prosthesis. Symptoms included pain, numbness, decreased hip motion, and a temperature of 38.5 degrees. The left leg was shortened, externally rotated, and swollen. There was anterior thigh hypoesthesia and quadriceps paralysis. A pulsatile mass in the lower left quadrant of the abdomen emitted a thrill and a loud bruit. A preoperative arteriogram facilitated diagnosis and planning of surgery. A transpubic femorofemoral bypass graft was used to reroute blood to the left lower limb, avoiding vascular reconstruction in the area of the aneurysm, a suspected site of infection. A false aneurysm was determined and was then isolated. The prosthesis was removed. During this operation, the acetabular component was found freely mobile within the false aneurysm. Cultures of the removed vascular tissue grew Staphylococcus epidermidis. An arteriogram should be obtained prior to operation for any medial intrapelvic displacement of a total hip prosthesis to diagnose the extent of vascular involvement. Physical examination may not reveal the aneurysm, but signs of neuropathy or venous thrombosis may suggest this diagnosis.