Hyperbilirubinaemia after major thoracic surgery: comparison between open-heart surgery and oesophagectomy.

BACKGROUND: Hyperbilirubinaemia is a common occurrence in patients who are admitted to intensive care units (ICUs) after major surgery, and it is associated with high mortality. We investigated the incidence of hyperbilirubinaemia after two major types of thoracic surgery: open-heart surgery and oesophagectomy. In order to identify the risk factors associated with hyperbilirubinaemia after major surgery, we compared the incidence after open-heart surgery with that after oesophagectomy. RESULTS: Hyperbilirubinaemia was detected in 51% of the open-heart surgery patients (n = 133) and in 64% in the oesophagectomy group (n = 74). The incidence of hyperbilirubinaemia was significantly related to the duration of surgery (P< 0.05). In the open-heart surgery group, duration of surgery was 465 +/- 24 min for the patients without hyperbilirubinaemia and 571 +/- 26 min for the patients with hyperbilirubinaemia. In the oesophagectomy group, the procedure durations were 415 +/- 17 min and 493 +/- 20 min, respectively. The overall mortality rate was 8% in the open-heart surgery group; the rate was 12% in those with hyperbilirubinaemia, but 5% in those without hyperbilirubinaemia. No members of the oesophagectomy group died, with or without hyperbilirubinaemia. Infection significantly affected both the occurrence of hyperbilirubinaemia and mortality in the open-heart surgery group. In the subgroups from the open-heart surgery group, 5% (three out of 65) of those without hyperbilirubinaemia (or evidence of infection) died; of the patients with hyperbilirubinaemia, 3% (one out of 38) of those without infection died and 23% (seven out of 30) with detected infection died. CONCLUSION: After open-heart surgery and oesophagectomy, approximately half of the patients studied had higher levels of serum total bilirubin. Time spent in surgery was significantly related to the occurrence of hyperbilirubinaemia. Infection significantly affected mortality and total bilirubin levels after open-heart surgery. Control of infection plays a crucial role in the prevention of hyperbilirubinaemia and in reducing mortality.

The influence of surgical stress on T cells: enhancement of early phase lymphocyte activation.

UNLABELLED: For the control of postoperative infection, it may be important to understand the possible influences of surgical stress on the host immune system. To this end, we examined how the early phase of lymphocyte activation was affected in patients after major surgery (eight patients with esophageal carcinoma and six undergoing cardiac surgery) using a flow cytometric assay based on expression of the early activation antigen, CD69. Freshly isolated T cell in preoperative and postoperative samples did not express CD69. When peripheral blood mononuclear cells were stimulated in vitro, the expression of CD69 was greatly enhanced in both CD4 and CD8 T cells, compared with the preoperative samples. The proportion of de novo CD69-expressing cells in the CD4 subset was approximately 3 times (Postoperative Day 1) and 4 times (Postoperative Days 2, 3, 5, and 7) greater than those preoperatively, whereas the proportion of de novo CD69-expressing cells in the CD8 subset was approximately 1.5 times (Postoperative Days 2 and 5) and 2 times (Postoperative Day 3) greater than those preoperatively. The proportion of CD69+ cells was significantly greater in the CD4+ subset than in the CD8+ subset during the postoperative period. IMPLICATIONS: Our results show that major surgical stress enhances the early phase of lymphocyte activation. The augmentation of activation was greater in CD4 (helper) T cells than in CD8 (cytotoxic) T cells.

Up-regulation of Fas ligand (FasL) mRNA expression in peripheral blood mononuclear cells (PBMC) after major surgery.

FasL, which is expressed mainly on activated lymphocytes, can induce apoptosis (programmed cell death) of cells which express Fas. Fas/FasL interaction is primarily beneficial in maintaining immunological and physiological homeostasis by eliminating unnecessary cells. Dysregulation of the interaction, however, leads to tissue damage. We investigated how Fas/FasL levels changed after major surgery. The major aim of this study was to elucidate the involvement of the Fas/FasL system in postoperative inflammation. The investigation involved 10 patients admitted to the intensive care unit after surgery. Although the percentage of Fas+ cells and the amount of Fas expression tended to increase, there was no significant difference between pre- and post-operative samples. In contrast, the levels of FasL mRNA were dramatically up-regulated after operation. Post-operative C-reactive protein (CRP) levels increased and correlated well with FasL levels (r=0.91, P<0.01). Lymphocyte counts decreased after operation and were inversely proportional to FasL levels (r=0.58, P < 0.05). These results suggest that the enhanced FasL expression is likely to be related to systemic inflammatory responses induced during the perioperative period. FasL up-regulation may be involved in the aggravation of tissue damage, including lymphocytopenia, in the early post-operative period.

Rapid screening for Staphylococcus aureus infection by measuring enterotoxin B.

We developed a simple, sensitive laser nephelometric assay (LNA) to detect circulating staphylococcal enterotoxin B (SEB). This assay yields the result within 2 h and needs no special treatment. Influence of protein A, a product generated by Staphylococcus aureus, was negligible in this assay. The levels of SEB in plasma were measured in 28 patients with and without S. aureus infection with the LNA. The levels of SEB in plasma increased significantly in patients with S. aureus infection. We also demonstrated that the levels of SEB in plasma were higher in patients with methicillin-resistant S. aureus infection than in patients with nonresistant staphylococcal infection. Our data indicate that LNA is a useful assay in the early diagnosis of methicillin-resistant S. aureus infection.

Improved high-performance liquid chromatographic determination of amphotericin B in human serum and plasma.

An improved reversed-phase high-performance liquid chromatographic procedure is described for the determination of Amphotericin B (AMB) in human serum and plasma. The procedure involves the addition of the internal standard, p-nitroaniline, to the sample (0.1 ml) followed by protein precipitation with acetonitrile. The supernatant is injected directly onto a C8 chromatographic column and eluted with an acetonitrile-aqueous 0.01 M sodium acetate buffer, pH 7.4, mobile phase. A spectrophotometric detector operated at 405 nm is used. Retention times for internal standard and AMB are 5.2 and 6.6 min, respectively. The assay standard curve is linear between 0.05-2.0 micrograms cm-3. Within- and between-run relative standard deviations (RSD) for high and low concentrations of the drug are less than 5.30%. Analytical recovery of added AMB in serum is 98.4-101.4%. Data obtained by microbiological assay correlated well (r = 0.936) with LC results. Some commonly co-administered drugs and high concentrations of bilirubin are shown not to interfere.

Rapid determination of amphotericin B levels in serum by high-performance liquid chromatography without interference by bilirubin.

A high-performance liquid chromatographic method for the determination of amphotericin B concentrations in human serum without bilirubin interference was developed and compared with a microbiological assay. The high-performance liquid chromatographic assay utilized a reversed-phase trimethyl silica column, simple sample preparation, and visible detection. Reproducibility studies yielded coefficient-of-variation ranges from 1.02 to 2.11% for within-day precision and 2.88 to 4.32% for between-day precision. The correlation coefficient with the microbiological assay was 0.984 for amphotericin B.

Determination of cyclosporin A in whole blood by high-performance liquid chromatography using automated column switching.

A fully automated high-performance liquid chromatographic column-switching system is presented for the determination of cyclosporin A in whole blood. After blood proteins were precipitated with acetonitrile, the supernatant was automatically loaded on to a cyanopropyl column for initial separation, and then the fraction containing cyclosporin A was loaded on to a trimethylsilica column for final separation and quantitation. Cyclosporin A was detected by ultraviolet absorption at 205 nm. The minimum detectable concentration of cyclosporin A was 5 ng/ml in 100 microliter of blood. The coefficient of variation of the method was 1.755, 1.748 and 0.655% in whole blood when spiked at the 170, 425 and 850 ng/ml levels, respectively. One assay was completed in 15 min.

Serial changes in cellular immunity of septic patients with multiple organ-system failure.

Total lymphocyte count, lymphocyte cell-surface markers (OKT3, OKT4, OKT8, and B-1), serum complement factors (C3 and C4), immunoglobulins (IgG, IgA, and IgM), ceruloplasmin (Crl), and transferrin (Trf) were determined weekly for nine septic postoperative patients, all of whom had multiple organ-system failure. The peripheral blood total lymphocyte count, its subpopulation, T-cell subset, and proliferative responses of lymphocyte to phytohemagglutinin (PHA) and concanavalin A (Con A) decreased in all patients. OKT3 and B-1 decreased progressively in the four nonsurvivors compared with the five survivors. Although immunoglobulin levels were within the normal range in both groups, they tended to increase in survivors and decrease in nonsurvivors. Serial levels of C3, C4, Crl, and Trf increased in survivors but did not change in nonsurvivors. T-cell function and antibody-producing activity diminished progressively in nonsurvivors. These changes in cellular immunity may represent another manifestation of multiple organ-system failure during sepsis.

Elimination of false-positive limulus amebocyte lysate tests in patients with hyperlipidemia.

Varying concentrations of lipopolysaccharide (LPS) and mannan suspensions were mixed with either saline or plasma from normal volunteers, heated to 100 degrees C for 10 min, and then subjected to the limulus amebocyte lysate test (LAL). A positive LAL in saline required minimum LPS and mannan concentrations of 10(-11) and 10(-5) g/ml, respectively, while the minimum concentrations premixed with plasma were 10(-13) and 10(-9) g/ml, respectively. Thus, use of plasma instead of saline increased assay sensitivity 100-fold for LPS and 10,000-fold for mannan. In the second part of the experiment, normal plasma was separated into lipid and nonlipid phases by Folch's method. LAL analysis of each phase revealed equal sensitivity for LPS and mannan in the nonlipid phase, but no sensitivity in the lipid extract. Subsequently, 200 ml of a fat emulsion (Intralipos) was administered to the normal volunteers, and LAL and lipid analyses were performed. The LAL turned positive in all volunteers. When LAL was positive, triglycerides (TG), chylomicron (Chyl), and very low-density lipoprotein (VLDL) increased significantly compared with when LAL was negative. It is concluded that plasma lipids increase the sensitivity of LAL and directly activate LAL when TG, Chyl, and VLDL concentrations are high. This effect of plasma lipids on LAL can be eliminated by extracting LPS and mannan in the nonlipid phase.

Determination of complement breakdown fragments C3d and its subfragments in health and disease.

The breakdown products of the third component of complement in approximately 400 samples were measured by rocket immunoelectrophoresis and two-dimensional electrophoresis using the method of Brandslund et al [3]. It was confirmed that the measurement of the C3d level provides useful information on increased C3 consumption irrespective of the synthetic rate. Furthermore, three subfragments with C3d but without C3c antigenicity were distinguished, which were designated as C3d1, C3d2, and C3d3. The subfragment C3d3 which migrated to the most anodal side was a predominant component in the plasma from patients with autoimmune diseases. Little C3d3 subfragment was detected in normal plasma and in normal sera incubated in vitro for 24 hr. Even in the normal sera converted completely in vitro which contained little intact C3, only a limited amount of C3d3 was detected. In the plasma from postsurgical patients in whom activation of the complement system was considered to be in an acute phase, C3d3 was detected, but the C3d2 level was higher than the C3d3 level. In the plasma from patients with systemic lupus erythematosus having the normal C3d level, C3d3 was a major fragment. It is predicted that the preponderant presence of C3d3 in plasma could be the result of chronic continuous complement activation by immune complexes.