J. P. Bengtson

Complement activation and reinfusion of wound drainage blood

Eighteen patients undergoing total hip replacement (n = 13) or knee arthroplasty (n = 5) due to osteoarthritis or osteoarthrosis were prospectively studied in an investigation of complement activation and anaphylatoxin release in association with reinfusion of aspirated wound blood. Twelve of the patients needed blood transfusions and received an average of 390 +/- 75 ml (+/- SD) of autologous blood within 45 min. Plasma complement components, anaphylatoxins, and inhibitors were studied 1 min before and 15 min after the start of and 15 min after the completion of autologous transfusion. Samples also were taken from the collected blood, before and after passing it through a microporous filter. Blood gases and systemic complement samples were drawn simultaneously. There were no significant changes in systemic complement variables before, during, or after transfusion of autologous blood. However, in the aspirated blood, increased concentration of anaphylatoxins (C3a and C5a) and terminal complement complexes (TCC) were present (P less than 0.001). There were no differences observed between samples drawn before and after filtration of the blood. The concentration of C5 was less in the collected blood than in the systemic blood (P less than 0.05). No changes in blood gases were observed. This study demonstrated that postoperatively salvaged whole blood underwent anaphylatoxin formation and complement activation. However, after reinfusion of this blood, neither systemic complement activation nor clinical complications were observed.

Complement activation during storage of whole blood, red cells, plasma, and buffy coat

BACKGROUND: The process of separating whole blood into components and the storage of blood components may cause the release of toxic metabolites from the complement cascade. The aim of this study was to determine whether the storage of blood components leads to the activation of the complement cascade and the release of anaphylatoxins.

COMPLEMENT ACTIVATION DURING LIVER TRANSPLANTATION

Twelve patients with end-stage liver disease undergoing liver transplantation were studied regarding complement activation and formation of anaphylatoxins (C3a and C5a) and terminal C5b-9 complement complexes (TCC) after reperfusion of the grafted liver. Blood samples for complement variables (C1INH, C3, C4, C5, C3a, C5a, and TCC) were drawn preoperatively, before the anhepatic phase, 1 min before, and 2, 15, and 60 min after the start of reperfusion of the grafted liver. Activation of complement was observed during the operation. The C1INH, C3, C4, and C5 plasma concentrations decreased during the entire operation while the anaphylatoxin C3a and the terminal C5b-9 complement complex increased after the reperfusion of the grafted liver. Activation of complement with the formation of biologically active substances like anaphylatoxins and terminal C5b-9 complement complexes may be one explanation for circulatory complications often seen in patients undergoing orthotopic liver transplantation.

Neutrophil and macrophage activation and anaphylatoxin formation in orthotopic liver transplantation without the use of veno‐venous bypass

Background. Activation of neutrophils and activation of complement may be an aetiologic factor behind circulatory insufficiency in association with reperfusion of the grafted liver.

Complement system activation during orthotopic liver transplantation in man. Indications of peroperative complement system activation in the gut.

Sixteen patients with acute and chronic liver disease undergoing OLT were studied regarding the role of the liver and the gut in complement activation. Also, the relation between complement activation and clinical manifestations during the liver transplantation reperfusion period was investigated. Blood samples for measurement of complement anaphylatoxin C3a (C3a), complement anaphylatoxin C5a (C5a), and terminal C5b-9 complement complex (TCC) were taken simultaneously from the central venous catheter and the radial arterial line before starting the operative procedure, 1 min before declamping, and 1–2 min, 5 min, 30 min and 6–12 hr after declamping. Simultaneous blood sampling from the radial arterial line, central venous catheter, portal vein, and hepatic vein was performed 1–2 min and 5 min after completed unclamping. Elevated plasma levels of C3a and TCC were found upon reperfusion, while C5a levels remained unchanged throughout the operation compared with the preoperative levels. The levels of C3a in the portal vein were higher compared with the levels in the simultaneously obtained samples from the radial artery. The results indicate complement cascade activation located to the gut during the reperfusion phase of OLT. Seventy-five percent of the patients studied suffered from the postreperfusion syndrome, indicated by profound hypotension upon reperfusion of the transplanted liver. There was a significant correlation between high concentration of C3a anaphylatoxin and development of profound hypotension.

Gas kinetics during nitrous oxide analgesia for labour.

Hypoxaemia may occur after hyperventilation with nitrous oxide during labour. The purpose of this study was to assess whether diffusion hypoxia is a contributory factor. Twenty‐four parturients were randomly allocated to receive 50 or 70% nitrous oxide in oxygen. The median nitrous oxide inhalation time per contraction was 58 s and 33 s, respectively. The end‐tidal carbon dioxide and the minute ventilation remained unchanged. The end‐tidal oxygen concentration was lowest at 120s, reaching 15.4% in both groups. The oxygen saturation did not differ between the groups with a lowest median value of 96% before the start of nitrous oxide inhalation. Two parturients had episodes ofdesaturation. Both had low end‐tidal oxygen concentrations in association with the desaturation but, as the end‐tidal nitrous oxide concentrations were low, the desaturations could not be attributed to diffusion hypoxia.

Autologous blood transfusion in radical hysterectomy with and without erythropoietin therapy.

OBJECTIVE To investigate whether preoperative treatment with erythropoietin facilitates the collection of a sufficient amount of autologous blood in a short period of time. METHODS Forty‐one women scheduled for radical hysterectomy were randomized to preoperative autologous blood donation with or without preoperative recombinant human erythropoietin therapy. All patients were scheduled to deposit three units of blood within 2 weeks before surgery. Hemoglobin, erythrocyte volume fraction, blood cells, iron status, and hemolysis were analyzed before and after surgery. RESULTS Hemoglobin levels decreased continuously in both groups after the first autologous donation until day 1 postoperatively. With erythropoietin therapy, the erythrocyte volume fraction and hemoglobin levels were significantly higher during precollection and day 1 after surgery. Preoperatively, the drop was 12 g/L less in the erythropoietin‐treated group. The additional use of erythropoietin therapy reduced the inability of patients to predeposit blood from 17.8% to 3.4%. CONCLUSION Most women can predeposit three units of whole blood in only 2 weeks without obtaining severe anemia. By treating women with erythropoietin, one out of seven can be prevented from a hemoglobin level below the 100 g/L limit for donation.

End‐tidal to arterial oxygen tension difference as an oxygenation index

Background: “Ideal” alveolar oxygen tension (PAO2) is a calculated entity and the alveolar‐arterial oxygen tension difference (PA‐aO2) is used to evaluate gas exchange function of the lungs. Accurate calculations of PAO2 necessitate measurements of the respiratory exchange ratio (RER), which is less frequently done, and most often approximations are made. The measured end‐tidal oxygen tension (PETO2) is a reflection of the alveolar oxygen tension. The aim was to study the relationship between PAO2 and PETO2, and to see whether the end‐tidal to arterial oxygen tension difference (PET‐aO2) could give the same information about lung function as PA‐aO2.

Recombinant human erythropoietin in preoperative autologous blood donation did not influence the haemoglobin recovery after surgery

Background: Recombinant human erythropoietin in combination with preoperative autologous blood donation is an established regime for avoiding allogenic blood transfusions. The aim of the study was to determine endogenous erythropoietin production and haemoglobin recovery after preoperative autologous blood donation and surgery, with or without recombinant human erythropoietin treatment.

Complement anaphylatoxin C3a and C5a formation in premature children with respiratory distress

Premature children (n=25) with respiratory distress (RD) were studied regarding complement activation and formation of the anaphylatoxins C3a and C5a. Blood samples were drawn on admission to the paediatric intensive care unit. In 18 of the patients RD was accompanied by other perinatal complications like pneumothorax or intracerebral haemorrhages. Seven of the premature children had RD without such complications. Preterm children with RD and with peri- and postnatal complications such as pneumothorax or intracerebral haemorrhage had increased concentrations in plasma of the anaphylatoxins C3a and C5a compared with preterm children with RD without these complications. There was a positive correlation between the plasma C3a and C5a concentrations in the preterm children.