Autotransfusion after open heart surgery: the oxygen delivery capacity of shed mediastinal blood is maintained.

Autotransfusion of mediastinal shed blood after open heart surgery has become a common and accepted procedure in reducing the need for homologous transfusion during the last 15 years. The objectives of the present study were to investigate the oxygen delivery capacity of autotransfused shed mediastinal blood, compared to patient-blood, during cardiopulmonary bypass and in the postoperative period. Ten consecutive patients undergoing elective cardiac surgery were studied. Mediastinal shed blood was collected in the cardiotomy reservoir and retransfused during the first 18 postoperative hours. The oxygen delivery capacity of the blood to the tissues was calculated by use of the oxygen status algorithm (OSA 2.0) programme and measurement of the 2,3-diphosphoglycerate (2,3-DPG) concentration. Autotransfusion volume ranged from 450-1530 ml per patient (median 824 ml). Shed blood had a mean haemoglobin level of 8.8 g/dl and 7.4 g/dl at 1 h and 6 h of autotransfusion, respectively. There were no significant changes of 2,3-DPG concentration in the patient-blood during cardiopulmonary bypass or after autotransfusion compared to preoperative values. P50 for oxygen (3.6 and 3.6 kPa) and 2,3-DPG concentrations (5.3 and 5.1 mikromol/ml erythrocyte) in shed mediastinal blood (1h and 6h postoperatively) were not significantly different compared to patient-blood. The results demonstrate that the oxygen delivery capacity of shed mediastinal blood is maintained and that the oxygen affinity of patient-blood is not influenced by autotransfusion.

Lung function and radiographic signs of pulmonary fibrosis in oil exposed workers in a cable manufacturing company: a follow up study.

Thirty seven workers employed for at least three years in oil impregnation of cables during 1963-83 were followed up in 1990 to study the development of pulmonary fibrosis and consequences for lung function. They had been exposed to concentrations of mineral oil vapours of 50-100 mg/m3, and concentrations of oil mist of 0.5-1.5 mg/m3. All 29 living persons were traced. For each person one control matched for age, height, and smoking habits was selected. Among 25 workers followed up with radiographic studies, 10 cases of pulmonary fibrosis were found, by contrast with one case in the control group (p less than 0.01). Chest radiographs from 1979-80 and 1989-90 were reviewed. The profusion of small opacities increased in seven of 16 persons during 10 years without exposure. Seventeen workers had lung function tests. The bellows function (VC, FEV1, MVV) and lung volumes (TLC, RV) did not differ from those in the matched controls (p greater than 0.05), but the carbon monoxide transfer factor (TLCO) was decreased. The largest reduction of TLCO (1.5 mmol/kPa/min) was found among workers exposed for 10 years or more (p less than 0.05). Arterial blood gases were not affected at rest, but during maximum tread mill exercise, PO2 and HbO2 were reduced in exposed workers compared with controls, particularly among those exposed for at least 10 years (p less than 0.05). Exposure to low viscosity oil mist and vapour is the most plausible cause of the fibrosis. Unaffected bellows function, reduced TLCO, and decreased arterial blood oxygen during exercise is compatible with peribronchiolar fibrosis.

Effect of iron treatment on erythrocyte parameters in postnatal anemia of the pig.

The development of postnatal anemia and the preventive and curative effect of iron supplementation were examined in 34 piglets from three litters of Norwegian Landrace pigs. A prostaglandin analog was given on day 111 or 112 of pregnancy, and the piglets were removed by caesarean section. Seventeen piglets were given 180 mg iron as colloidal ferridextran subcutaneously at birth (0 = day group); the remaining 17 were given the same amount on day 13 (13-day group). The piglets had access to a milk substitute from day 1 to day 7 and pelleted food for piglets after day 13. From about 4 weeks of age the piglets ate considerable amounts of pellets. The red blood cell count (RBC) and hemoglobin concentration (Hb) at birth were 3.2 +/- 0.4 (SD) x 10(12)/L and 80.4 +/- 8.1 x 10(12) g/L, respectively. In both groups Hb, RBC, mean corpuscular volume (MCV), and particularly packed cell volume (PCV) decreased markedly the first day after birth. In the 13-day group there was a further decrease until treatment with iron on day 13. Injection with iron on day 13 led to a rapid increase in the above mentioned parameters, with statistically significant increases for Hb, PCV, and MCV four days after treatment. The calculated mass of hemoglobin was fairly constant until treatment in the 13-day group. In the group given iron at birth the data obtained indicate that the amount of iron given is insufficient to sustain a production of normal-sized erythrocytes with a normal mean corpuscular hemoglobin concentration for more than approximately 21 days. Furthermore, the present study also indicates that MCV is a sensitive indicator of iron availability in piglets.

Regulation of erythropoiesis in suckling rabbits with and without postnatal anemia: partial suppression of production/release of erythropoiesis stimulating factor(s) by iron supplements.

The postnatal anemia in rabbits is accompanied by a marked rise in the plasma erythropoiesis stimulating factor(s) (ESF). The purpose of this study was to establish whether the increase in plasma ESF is only related to the anemia, or whether other mechanisms also are involved. Two matched groups of rabbits were studied from the 15th to the 36th day after birth. One group received iron parenterally and had no postnatal fall in hemoglobin concentration (Hb), the other developed the usual anemia. In both groups plasma ESF was undetectable on the 15th day, and also on the 22nd day, despite a marked fall in Hb in the untreated group and rise in the iron-treated group. Thereafter plasma ESF showed a slight, continuous rise in the nonanemic rabbits, in contrast to a marked, transient rise with maximum on the 29th day in the untreated group. On the 36th day there was no difference between the groups. In the iron-treated group the reticulocyte production rate remained unchanged, while the Hb mass rose continuously. In the untreated animals there was an initial decline in reticulocyte production rate, while Hb mass showed a slight increase. From the 29th day, however, reticulocyte production rate rose to the same level as in the iron-treated group and Hb mass rose markedly. In conclusion, the rise in plasma ESF during the postnatal anemia in rabbits is only in part related to the low Hb. Hypoxia-independent mechanisms, probably related to the growth and maturation per se also are involved. The lack of erythropoietic response to the rise in plasma ESF is due to lack of available iron.

Erythrocyte 2,3-diphosphoglycerate, PO250%, and available oxygen in young rabbits with and without postnatal fall in hemoglobin.

We determined erythrocyte 2,3-diphosphoglycerate (2,3-DPG), PO250%, whole blood hemoglobin concentration, and available O2 from the 12th to the 30th d after birth in two matched groups of young rabbits. One group received iron parenterally on the 12th, 15th, and 18th d and the other received no iron supplement. In the untreated group there was a marked fall in hemoglobin concentration from the 12th to the 22nd d and thereafter a marked increase to the initial level on the 30th d whereas the iron-treated animals showed a marked rise in hemoglobin concentration from the 12th to the 22nd d, and a subsequent, slight decline from the 22nd to the 30th d. The average values of PO250% and 2,3-DPG, and the changes in PO250% and 2,3-DPG were virtually identical for both groups. During the first period (12-22 d) there was a marked rise in both 2,3-DPG and PO250% whereas in the second period (22-30 d) there was a somewhat smaller rise in 2,3-DPG and only a slight tendency toward a further rise in PO250%. In the untreated animals "available O2," reflecting the O2 delivery capacity of the blood, remained unchanged during the period of fall in hemoglobin concentration and showed a rise during the second period. In the iron-treated animals "available O2" rose markedly during the first period, with iron-treatment, and remained unchanged during the second period. We conclude that the marked postnatal rise in 2,3-DPG and PO250% in the rabbit seems to be independent of the changes in the hemoglobin concentration.

Erythrocyte 2,3-DPG, PO2 50% and available O2 during the early post-natal fall in hemoglobin in rabbits.

Erythrocyte 2,3-DPG, PO2 50%, whole blood hemoglobin and available O2, and fixed acid Bohr effect were studied during the first 10 days after birth in rapidly growing suckling rabbits. The post-natal fall in hemoglobin concentration was accompanied by a marked rise in erythrocyte 2,3-DPG and a gradual increase in PO2 50%. The rise in PO2 50% was sufficient to keep the available O2 of the blood unchanged throughout the observation period. The observations show that a 2,3-DPG mediated rise in PO2 50% very effectively contributes to maintenance of adequate tissue oxygenation during the post-natal fall in hemoglobin. The rise in 2,3-DPG and and PO2 50% may be due to the ordinary hypoxia-induced shift to the right of the hemoglobin O2 dissociation curve, as observed under other circumstances when blood hemoglobin is rapidly reduced, but the very marked rise in 2,3-DPG and the very low delta PO2 50%/delta 2,3-DPG ratio suggest that the rise may as well be due to hypoxia independent, pre-programmed processes. The fixed acid Bohr effect was essentially the same in newborn and adult rabbits, and was uninfluenced by large variations in 2,3-DPG.

Relationship between urine flow, glomerular filtration, and urine solute concentrations during prolonged heavy exercise.

Serum and urine electrolytes, creatinine, and urea were determined in 21 well-trained men, aged 21-56 years, in connection with a 70-km cross-country ski race, lasting 4.39-6.52 h, leading to slight dehydration. Although the race urine flow was low, averaging 0.41 (0.1-0.9) ml/min, the average urine concentrations of urea, Na, Ca, Mg, Cl and P were markedly lower than during the preceding night, while the concentrations of K and creatinine were higher, the total of measured solutes being 621 nmol/l, compared with 911 nmol/l during the preceding night. Decreasing urine flow and endogenous creatinine clearance were accompanied by a falling urine solute concentration, particularly when the race creatinine clearance decreased to below 70 ml/min, mainly due to a fall in the urea, Na, and Cl concentrations. Thus, a decrease in the glomerular filtration rate was accompanied by a progressive decline in the urine concentrating ability.