[Risk factors of surgical wound infection]

The risk of developing a surgical wound infection depends on the balance between factors determining the number of bacteria contaminating the wound and factors determining the resistance of the wound against infection. Some of these factors are responsive to interventive strategies, aiming at lowering the frequency of surgical wound infection. It has been shown, that the use of prophylactic antibiotics and ultraclean-air operation room techniques are beneficial in certain types of surgery, while the use of blood transfusion increases the risk of wound infection. Evidence suggests that the use of laparoscopic techniques in abdominal surgery will decrease the risk of infection. Research in immunological factors and hypoxia have not yet contributed any clinically applicable types of prophylactic strategies.

Urinary thromboxane B2 as an indicator of acute rejection in human liver transplantation

Urinary thromboxane B2 (u-TXB2) was measured and analyzed after a human liver transplantation in 28 patients (30 transplantations) who underwent an orthotopic liver transplantation. Our results showed that the u-TXB2 levels exceeded 3.0 micrograms/mmol creatinine in only 2 of the 13 cases that had a favorable postoperative course. In 10 of the 11 episodes of acute rejection, the u-TXB2 levels exceeded 3.0 micrograms/mmol creatinine. In 6 episodes of acute rejection, the TXB2 levels were more than 5.0. In 4 out of 6 episodes of infection unassociated with rejection, the u-TXB2 values were between 3.0 and 4.9 micrograms/mmol creatinine. In 2 episodes of liver necrosis the TXB2 value reached 5.3 in one and 0.9 in the other. In conclusion, the u-TXB2 level was observed to be elevated in cases of acute rejection, infection, or necrosis. The diagnosis of acute rejection on the basis of u-TXB2 showed a sensitivity of 58.8%, a specificity of 93.3%, and an accuracy of 75.0% for a threshold level of 3.0 micrograms/mmol creatinine, and a sensitivity of 85.7%, a specificity of 79.2%, and an accuracy of 80.6% for a threshold level of TXB2 of 5.0 micrograms/mmol creatinine. These results indicate that the serial determination of u-TXB2 is a useful diagnostic means for predicting acute rejection after liver transplantation.

Defective neutrophil actin polymerisation and chemotaxis in stressed newborns

Abnormalities of polymorphonuclear leukocyte (PMN) function contribute to high rates of postoperative infection in the newborn and to the vulnerability of newborns to overwhelming bacterial and fungal sepsis. The authors investigated (1) the effects of major surgery and sepsis on PMN chemotaxis in the newborn and (2) the role of cytoskeletal rearrangements in regulating chemotaxis. The subjects studied included newborns with sepsis (n = 16), newborns who underwent major surgery (n = 7), healthy full-term newborns (n = 21), and healthy adult volunteers (n = 28). Peak actin polymerisation was diminished in all newborns (relative to the adults) after stimulation with formyl methionyl leucyl phenylalanine (FMLP) (10 nmol/L), and with zymosan activated serum (ZAS) (10%). Major surgery and sepsis in newborns caused no further reduction in actin polymerisation. Changes in PMN shape after stimulation with FMLP were reduced in the newborns. PMN chemotaxis was significantly lower in healthy newborns than in adults (17 +/- 4 microns v 24 +/- 5 microns; P < .0001) and was even lower in septic newborns (11 +/- 4 microns; P < .005). Surgery and anaesthesia did not alter chemotaxis.

[Evaluation of the effectiveness of immunomodulators in the treatment of patients with postoperative suppurative-septic complications]

The influence of immunoactive medicines on the cell immunity have been studied. There were differences in reaction to T-activin and Thymalin between various patients with septic postoperative complications. Thymalin stimulated T-cells while acting with immunoglobulins or immune plasmas only. T-activin led to the increase in the number of T-lymphocytes and B-lymphocytes independently of it's cooperation with the vaccines. The stimulating effect of myelopid demonstrated itself by increase in the number of B-lymphocytes and immunoglobulins M and G after 14 days of treatment. The positive clinical effect was more impressive when immunomodulators were used in combinations with the vaccines; still it did not correlate completely with the dynamics of the cell immunity parameters.

[Effect of surgical trauma on NK cell activity in esophageal carcinoma after transmediastinal dissection vs. transthoracic en bloc resection]

In order to assess the impact of surgical trauma involved in the therapy of esophageal carcinoma on the cellular immune system, a perspective study was performed involving perioperative hematological parameters. The activity of natural killer cells and the serum concentrations of interleukin-2, interleukin-6 and TNF-alpha were measured in 12 cases of transmediastinal dissection and 10 cases of transthoracic en bloc esophageal resection and compared to values of a control group of thoracic and abdominal surgical patients with non-malignant maladies. Natural killer cells assume a central role in the non-specific immunological response in tumor patients. Their main function is the destruction of tumor cells via cytotoxic activities amplified by the release of interleukin-2 and TNF-alpha. Natural killer cell activity was measured prior to surgery and on postoperative days 4 and 10 using a standardized europium chloride release assay, utilizing K562 target cells. Lymphokines interleukin-2, interleukin-6, and TNF-alpha were also measured on postoperative days 1 and 7 using standardized ELISA assays. The activity of natural killer cells in our patient group sank significantly (P < 0.05) on postoperative day 4 and likewise in the control group and both study groups, activity sank to the original values. In the control group, natural killer cell activity averaged 45% of preoperative values, in comparison with an average of 63% following transmediastinal esophageal carcinoma resection (one cavity procedure), and transthoracic en bloc resection (two cavity procedure). On postoperative day 10, all groups displayed a significant reacceleration of natural killer cell activity (P < 0.05). Whereas transthoracic en bloc resection patients only reached 61% of preoperative values, transmediastinal dissection patients assumed 75%, and 77% was achieved by control group members. Transthoracic en bloc resection of the esophagus led to a more extreme reduction in cytotoxic cellular activity owing to the greater surgical trauma. Suppression of the immunological tumor resistance, especially in the vulnerable perisurgical phase, can have an indirect negative effect on the manifestation risk of hematogenic metastases owing to intraoperative tumor cell dissemination resulting from tumor manipulation and may thus be prognostically relevant.

Postoperative infection following orthopaedic surgery in human immunodeficiency virus-infected hemophiliacs with CD4 counts < or = 200/mm3

Human immunodeficiency virus-infected hemophiliacs are at risk for bacterial and opportunistic infections with worsening immunosuppression. Thus, the risk of postoperative infection following orthopaedic surgery is of considerable concern. A survey of United States hemophilia treatment centers was conducted to determine the incidence of postoperative infection in human immunodeficiency virus-positive hemophiliacs with CD4 counts of 200 mm3 or less undergoing orthopaedic surgery. A total of 115 centers from 37 states reported that postoperative infection occurred in 10 (15.1%) of 66 patients undergoing 74 orthopaedic procedures, between several weeks and 5 months following surgery. In five (50%), pre-operative infection preceded postoperative joint infection. Staphylococcus was the most common organism isolated in a prosthetic joint infection, in 6 of 10 (60.0%), and the knee was the most commonly affected joint, in 9 of 10 (90.0%). Joint arthroplasty appeared to have 10 times the risk of nonarthroplasty procedures for postoperative infection (9 of 34 [26.5%] and 1 of 40 [2.5%], respectively, P < .01). Two subjects developed chronic osteomyelitis. The rate of postoperative infection in human immunodeficiency virus-positive hemophiliacs with CD4 counts of 200/mm3 or less appears to be high, when compared with the general population. Early, vigorous treatment should be instituted for suspected infection, antibiotic prophylaxis considered for invasive procedures, and surgical intervention individualized based on the balance of risks and benefits.

Infective complications after minor operations in patients infected with HIV: role of CD4 lymphocytes in prognosis

OBJECTIVE

To find out the incidence of wound infection in patients with HIV and reduced counts of CD4 lymphocytes.

DESIGN

Open study.

SETTING

University hospital, Spain.

SUBJECTS

70 patients with HIV infection and enlarged lymph nodes.

INTERVENTIONS

Biopsy of lymph nodes and withdrawal of a sample of blood for counts of CD4 lymphocytes and neutrophils.

MAIN OUTCOME MEASURE

Development of infection at the biopsy site, and correlation of infecting organism with culture taken at the time of biopsy.

RESULTS

Patients were divided into three groups depending on their CD4 count: more than 500 cells/ml (n = 26), 200-500 cells/ml (n = 24), and less than 200 cells/ml (n = 20). Their neutrophil counts were 5.1, 3.8, and 2.5 x 10(9)/1, respectively. There were found four wound infections (6%); 2 were in the group with more than 500 CD4 cells/ml, and these were caused by Staphylococcus aureus (which had been grown from nodes in 6 patients at the time of biopsy). The other 2 were in the group with less than 500 cells/ml and these were caused by Mycobacterium tuberculosis; cultures of the nodes had shown Staphylococcus epidermidis (n = 3) and M tuberculosis (n = 17). There were no infections in the group with 200-500 CD4 cells/ml, in which S epidermidis (n = 5) and M tuberculosis (n = 8) had been cultured from the lymph nodes.

CONCLUSIONS

The CD4 count was of no prognostic importance in the development of wound infection, but severe depression of the CD4 count may increase the risk of atypical wound infections.

Surgery and the release of a neutrophil Fc gamma receptor

BACKGROUND

The fact that the incidence and mortality from postsurgical sepsis have remained unchanged over the past 15 years raises the possibility that some patients possess an idiosyncratic predisposition to the development of a postoperative sepsis response. Genetic polymorphisms of the neutrophil receptor for immunoglobulin G, CD16, are known, and their inheritance is associated with functional differences in neutrophil phagocytosis. The present studies were designed to provide preliminary data on the effects of surgery on the level of expression of CD16 and its metabolism preparatory to detailed examination of the relationship of these polymorphisms to sepsis responses.

PATIENTS AND METHODS

Neutrophil CD16 expression was measured by flow cytometry before and after operation in patients undergoing major resectional surgery of the digestive tract. Assays were performed on whole blood preparations as well as on isolated and activated neutrophil preparations from these patients.

RESULTS

Neutrophil CD16 expression was constitutively higher both before and after surgery in patients who developed a postoperative sepsis response than in those who did not. Surgery had no effect on the level of surface neutrophil CD16 expression in either group. Surgery depleted intracellular CD16 stores despite the maintenance of a constant level of CD16 on the neutrophil surface, membrane-bound CD16 being more readily cleaved by physiological neutrophil activators after surgery than before surgery.

CONCLUSIONS

The intrinsic level of expression and postsurgical metabolism of neutrophil CD16 may be an important component of the predisposition of some patients to develop infection or sepsis after injury. Further studies of the distribution of CD16 allotypes and neutrophil function among surgical patients are warranted.

Alterations in lymphocyte subsets as prognosticators of postoperative infections

OBJECTIVE

To evaluate changes in lymphocyte subsets after major abdominal and thoracic operations, and to correlate changes with the development of clinically relevant infections postoperatively.

DESIGN

Open study.

SETTING

University hospital, Italy.

SUBJECTS

33 patients who were to undergo major abdominal or thoracic operations.

INTERVENTIONS

Lymphocyte subsets were measured by cytofluorimetry before operation and 1, 3, 5, and 7 days postoperatively.

MAIN OUTCOME MEASURES

Correlation between changes in the number of lymphocyte subsets and development of infection.

RESULTS

Lymphocyte subsets were within the reference range in all patients before operation. 10/33 Patients developed infections (pneumonia, bacteraemia, or wound or urinary tract infections) between the second and the ninth days postoperatively (30%). On day 1 the numbers of all lymphocyte subsets had decreased significantly compared with the preoperative measurements in all patients (CD3 p < 0.01, CD4 p < 0.001, and CD8 p < 0.05). The reduction in CD3 was significantly greater in the group that developed infections (p < 0.001). Among patients who did not develop infections the numbers of lymphocyte subsets had returned to the reference range within a week of operation whereas among patients who developed infections they remained depressed (p < 0.05).

CONCLUSION

The synchronous reduction in numbers of all lymphocyte subsets on the first day postoperatively to below 50% of the reference range (CD3 to < 600/microliters, CD4 to < 400/microliters, and CD8 to < 250/microliters) predicted the development of infection postoperatively with an accuracy of 89%, a sensitivity of 80%, and a specificity of 96%.

[Blood-saving surgery]

Trauma, blood loss and autologous blood transfusions induce a variety of changes in the reactivity of patients' immune systems. In clinical studies the differentiation of these effects is difficult. Association between autologous blood transfusion and postoperative infection is highly likely. In surgical oncology blood transfusions are associated with poor prognosis, but probably this is more because of the circumstances that necessitate them.

[Candida infection in surgery]

Candida sepsis in surgical patients is rare, but accounting for a high lethality. The diagnosis of a candidemia is based by most authors upon two positive blood cultures in 24 h or on proof of fungi in an organ parenchyma or a normally sterile body cavity. The risk factors for the development of a candida sepsis are administration of broad spectrum antibiotics, invasive monitoring, underlying diseases affecting the immune response and surgery itself. We have checked the charts of 22,740 patients of our clinic from 1987-1992. We found 11 patients (6 male, 5 female) with a mean age of 53.2 (34-76) years with a candida sepsis. The known risk factors for the development of a candida sepsis could be confirmed: broad spectrum antibiotics 100%, invasive monitoring 100%, condition after operation 64%, nasogastric tube 54%, condition after endoscopy 45%, steroid medication 36%. Lethality was 27% (3/11); two out of three patients with a multiple organ system failure died. Recently, it has been shown that mortality was associated with older age and concomitant multiple organ system failure. The treatment of choice for fungal sepsis is intravenous amphotericin B. Finally therapeutic guidelines, the indication for a selective bowel decontamination and the question of prophylaxis with antifungal agents in all postoperative patients are discussed.

Infections in the immunocompromised patient

Specific microorganisms have certain types of host defenses directed at them. Inhibition of different host defenses, therefore, leads to an increased risk of the host for infection with different organisms. This article discusses the types of infections present in immunocompromised patients as well as a general approach to diagnosis and treatment.

Nutrition and infection

It is now apparent that nutritional status has a profound impact on immune function and that the immune system may be modulated by the use of specific modes of nutritional support. In selected malnourished or severely injured patients, early nutritional support has been shown to improve outcome and decrease the incidence of infectious complications following major surgery or trauma. Enteral feedings appear to support the immune system better than parenteral feedings. TPN, although a potentially life-saving modality, should not be used indiscriminantly and should be limited to those severely malnourished or injured patients who are incapable of tolerating enteral feedings. The patient's metabolic needs should be assessed as accurately as possible, and the appropriate combination of substrates should be provided according to the patient's level of hypermetabolism. Overfeeding should be avoided. A number of nutritional substrates have been identified which may potentially modulate specific aspects of immune function. Among these, glutamine, arginine, and omega-3 fatty acids have demonstrated potential clinical usefulness. Iron deficiency appears to be a normal host defense response to infection or trauma and should not be compromised by attempts at iron replacement therapy. In summary, optimal nutritional support of the surgical patient supports the immune system and reduces the morbidity and mortality associated with severe malnutrition or injury.

Local immune inflammatory response to infected total hip and knee replacements

We studied the tissue response for periprosthetic pseudosynovial tissue in seven patients with a purulent endoprosthetic infection and six patients with common prosthesis loosening, using specific monoclonal antibodies in avidin-biotin-peroxidase complex staining. In infected cases, proline 4-hydroxylase positive fibroblasts dominated the stroma of the vascularized periprosthetic connective tissue, whereas diffuse local infiltrations of mononuclear cells characterized the cellular histological overview. Local cellular response consisted of CD11b and MHC locus II antigen-positive immunoreactive monocytes/macrophages and of T lymphocytes, mostly of the CD4 subset. Only a few CD25-positive cells could be detected. The local cellular response in six patients with prosthesis loosening of nonbacterial origin was mild, showing a sparse perivascular infiltration of CD11b- and Ia-positive monocytes/macrophages and CD4/CD8-positive T lymphocytes in a proportion of 2:1. Only occasional CD15- or lactoferrin-positive neutrophils and CD25-positive lymphocytes could be detected. Our results from chronically infected joint replacements suggest that neutrophils, being virtually absent in the tissue compartment, do not contribute to pathological events in the "pseudojoint" cavity, whereas local tissue response consists of a mononuclear inflammatory cell reaction of a macrophage-dependent foreign-body type.

[Initial experience with monoclonal antibodies in therapy of life threatening nosocomial infections in the neonatal period]

Despite the use of modern broad spectrum antibiotics nosocomial infections are an unsolved problem, especially in the field of neonatal intensive care (preterm babies and newborns). In patients with septic shock human monoclonal antibodies in combination with appropriate antibiotics have proven effective and compatible for children older than one year. So far, there have been no reports in the literature on the application of such kind of antiendotoxin immunotherapy for pre-term babies and newborns. We describe the effectiveness of monoclonal antibodies in two newborns. Already 12 respectively 16 hours after application of the human monoclonal IgM antibodies (Centoxin) and appropriate antibiotics, the clinical condition of our patients stabilized. Consecutively further clinical symptoms improved rapidly.

[Determination of antimicrobial activity of wound discharge for assessing wound healing]

The authors studied the dynamics of changes of antimicrobial activity of the wound discharge in 70 patients, aged from 18 to 83 years, who underwent operations for emergency diseases of the abdominal organs with postoperative suppuration of the wound. The study was conducted at the peak of suppuration, in the regeneration phase, and before closure of the wound with sutures. The antimicrobial activity of the wound discharge was found to be low at the peak of wound suppuration with marked necrotic changes of the tissues, as well as in poor granulations, and good in uncomplicated course of the wound process. Changes of antimicrobial activity of the wound discharge, both in uncomplicated and complicated course of the wound process, correlated with the clinical signs of healing. The obtained data make in possible to determine antimicrobial activity of the wound discharge for evaluation of healing, prognostication of bacterial complications in the wound, and control over the efficacy of the treatment.

[Blood transfusion increases the risk of surgical infection]

In a prospective randomized trial the frequency of infectious complications and natural killer cell function were investigated in 197 patients undergoing elective colorectal surgery and having either no blood transfusion (n = 93), transfusion with whole blood (n = 56), or filtered blood free from leucocytes (n = 48). Postoperative infections developed in 13 patients transfused with whole blood (23%), in one patient transfused with blood free from leucocytes (2%) and in two non-transfused patients (2%) (p < 0.01). Natural killer cell function was significantly (p < 0.001) impaired up to 30 days after surgery in patients transfused with whole blood. These data provide a strong case against the use of whole blood transfusion in patients undergoing elective colorectal surgery.

[The role of tissue lymphocytes in the healing of suppurative wounds in the maxillofacial area]

The authors have followed up the time course of lymphocytes during healing of postoperative wounds of the face and neck. Three waves of lymphocyte activation and proliferation were distinguished. The first wave preceded the macrophagal stage of an inflammatory reaction, the second the fibroblastic regeneration phase, and the third anticipated wound epithelialization.

[Clinical effects of blood transfusion-associated immune modulation on outcome of tumor surgery]

Extended experimental studies revealed different immunological mechanisms which are possibly responsible for blood transfusion-associated immunosuppressive conditions. To expect a clinical impact of these mechanisms on the course of tumor disease, it is necessary to postulate (1) that immunological mechanisms have a significant role in controlling tumor growth and (2) that blood transfusion-induced immunmodulation is long lasting. Both postulates are supported by recent reports and are the rationales of clinical studies indicating that blood transfusion is a risk factor for postoperative infections and tumor recurrence. Since all studies have been retrospective or uncontrolled, we performed a prospective controlled study in randomized groups of patients suffering from colorectal cancer and compared the effects of allogeneic and autologous blood transfusions. The results indicate that patients treated with allogeneic blood transfusion had significantly higher rates of postoperative infectious complications than patients who received autologous blood. Our preliminary follow-up observations found a trend towards higher tumor-free survival in patients treated with autologous blood which is statistically significant in subgroup analysis.

Bronchoalveolar lavage and transbronchial lung biopsy during acute rejection and infection in heart-lung transplant patients. Studies of cell counts, lymphocyte phenotypes, and expression of HLA-DR and interleukin-2 receptor

The total and differential cell counts of 135 bronchoalveolar lavages (BAL) in 48 heart-lung transplant (HLT) patients were compared with the histologic findings in concurrent transbronchial lung biopsies (TBBs). Counts of CD3+, CD4+, and CD8+ lymphocytes were recorded, and a semiquantitative assessment of HLA-DR and interleukin-2 receptor (IL-2R) expression was made on 29 occasions. There were five diagnostic categories: normal (n = 8), acute rejection (ALR) (n = 57), treated rejection (TR) (n = 19), infection (INF) (n = 24), and chronic rejection (CR) (n = 24). Total cell counts in INF were significantly higher than counts in all the other diagnostic groups. The highest BAL lymphocyte counts, significantly higher than in INF, were found in ALR because of increased CD8+ cells, exceeding 15% in 13 of 57 BALs. TBBs in ALR by contrast showed significantly increased numbers of both CD8+ and CD4+ cells. High dose corticosteroid treatment of ALR caused a fall in cellularity of BAL and TBB specimens but not always to values seen when patients were well. During INF and CR, significantly increased numbers of PMNs were seen in the BAL. HLA-DR and IL-2R expression was enhanced in cells of BAL and TBB in all complications. BAL can only supplement at present histologic examination of TBB in the diagnosis of complications after HLT.

[Opportunistic infections in patients with disordered immune status]

Dysfunction of the immune system can result in opportunistic infections, which are frequently responsible for high morbidity and mortality. With regard to surgery, opportunistic infections are found in specific risk groups, including individuals with tumors, AIDS, thermic or mechanical trauma and organ transplantation. These infections can be caused by bacteria, fungi, viruses and protozoa. If there are indications of a possible opportunistic infection, a rapid diagnosis is required, followed by immediate therapeutic intervention.