Immune response in the surgical patient: effect of anesthesia and blood transfusion

Anesthesiology has progressed spectacularly over the last two decades, largely parallel to developments in basic and clinically applied sciences such as immunology. The anesthesiologist's involvement now extends to all matters involved in perioperative care. Surgery, anesthetic procedures themselves, and other associated techniques such as blood transfusion all alter the patient's immune response and all fall within the range of procedures monitored by the anesthesiologist. The repercussions on the patient are important, given that alterations suppose increased risk of postoperative infection and increased recurrence of neoplastic disease. The present article reviews available knowledge on how and to what extent the patient's immune status is affected in the perioperative period. Generally, surgery and anesthesia induce immune system depression. It is possible to demonstrate a decrease in the number and activity of circulating immune cells and alterations of various types in interleukins and in protein synthesis during acute phase response. Research in this field is complex given that the individual effect of each factor involved is difficult to measure and experimental or clinical designs usually yield only biased views. Replacement of lost red blood cells is another factor leading to immunological changes. New anesthetic techniques, the optimization of methods already in use, and the development of modern, less immunodepressant drugs and of alternatives to homologous blood transfusion are all solutions that have been proposed. This is an exciting field of study in which today, perhaps more than ever, the anesthesiologist has a critical role to play.     

Massive transfusion of blood in the surgical patient

Hemorrhage remains a leading cause of morbidity and death in both civilian and military trauma. Restoration of effective end-organ perfusion by stopping hemorrhage and restoring intravascular volume in such a way as to minimize acidosis, hypothermia, and coagulopathy, almost always requires the use of blood and/or blood-component therapy. The best method to manage life-threatening hemorrhage is to avoid the circumstance that prompted it or to mitigate blood loss early in the injury cycle; otherwise, blood replacement must suffice. This article reviews current understanding of massive transfusion, along with its attendant unintended consequences, in the management of patients with profound hemorrhage.     

The effect of neuraxial blocks on surgical blood loss and blood transfusion requirements: a meta-analysis

PURPOSE: The aim of this study was to evaluate the effect of neuraxial blocks on surgical blood losses and on the number of patients requiring blood transfusion. METHODS: A search of the American National Library of Medicine's PubMed up to November 12, 2004, was performed. Twenty-four studies could be kept for analysis. RESULTS: Regional anesthesia reduced the number of transfused patients for total hip replacement (P = 0.0009) and spinal fusion (P = 0.04). A reduction of measured blood loss that did not lead to a reduction in the number of transfused patients was also found for fractured hip surgery (P < 0.0001), lumbar disk surgery (P = 0.01), peripheral vascular surgery (P = 0.03), retropubic prostatectomy (P = 0.02), cesarean section (P < 0.0001), and bowel surgery (P = 0.0008). In summary neuraxial blocks have a clear and definite effect on surgical blood loss, but this effect do not usually lead to a reduction in the number of transfused patients except for patients undergoing total hip replacement and spinal fusion.     

The effect of blood transfusion on immunological response in mice]

Recent clinical and experimental studies have suggested that blood transfusion decreased immunological responsiveness. In order to investigate this mechanism, we performed following studies. In vivo experiments, we investigated the effect of blood transfusion on tumor growth and survival rate in mice, and added the comparative studies about the timing of blood transfusion and blood cell component transfusion. In vitro experiments, we studied on the responses of CTL and NK activity by the experimental model of postoperative blood transfusion. These experiments led to the following results: 1) Accelerated tumor growth and reduced survival rate were observed in allogeneic transfused mice. 2) These effects were seen independently of the timing of blood transfusion. 3) A transfusion of lymphocytes was capable of inducing this effect of blood transfusion. 4) Blood transfusion induced both suppression of anti-tumor CTL, TNP-CTL and NK activity. 5) The suppression of CTL was mediated by suppressor cells. From these results, it was suggested that allogenic blood transfusion induced immunosuppression in mice independently of its timing.     

Anaemia and blood transfusion: incorporating patient blood management

Both red blood cell (RBC) transfusion and anaemia or low haematocrit increase morbidity and mortality associated with surgery. Chronic anaemia in the elective patient carries a small risk in non-haemorrhagic surgery. Where bleeding is anticipated anaemia should be treated medically to avoid (RBC) transfusion which will increase the risk to the patient. Major bleeding (MB) has the biggest impact on adverse outcomes. Acute anaemia is caused by surgical bleeding and requires RBC transfusion to keep the haematocrit (Hct) above 21% and haemoglobin (Hb) above 7 g/dl in patients without coronary artery disease (CAD) and between Hct 24–27% or Hb >8 g/dl in patients with CAD. Having a patient blood management programme can mitigate the problem. Medical, surgical and anaesthetic planning are paramount to avoid bleeding and transfusion which together have a significant impact on adverse outcomes for the patient.     

The effect of spinal anesthesia on blood transfusion rate in total joint arthroplasty.

BACKGROUND: Total joint arthroplasty (TJA) patients often receive allogeneic blood transfusion. The use of regional anesthesia (RA) is thought to protect against the need for blood transfusion, but many randomized trials of RA in TJA have not reached this conclusion unanimously. We sought to describe the effect of RA on allogeneic transfusion in a large retrospective TJA series. METHODS: We examined data from all TJAs performed in Edmonton, Alberta, in the year 2000 (n = 1875) and used logistic regression modelling to determine the relation between the use of RA and allogeneic transfusion. RESULTS: Twenty-eight percent of TJA subjects received an allogeneic transfusion. Transfusion was independently associated with increasing age, decreasing body mass, decreasing preoperative hemoglobin, female sex, increased comorbidity and prolonged operative time. After controlling for these factors, we found that the use of RA (in the form of spinal anesthesia) compared with general anesthesia reduced the odds ratio (OR) for transfusion to 0.729 (95% confidence interval [CI] 0.559-0.949). This represents the combination of a strong relation between RA and transfusion prevention in hip arthroplasty (OR 0.646, 95% CI 0.443-0.944) and a nonsignificant relation in knee arthroplasty (OR 0.825, 95% CI 0.564-1.208). CONCLUSION: The use of spinal anesthesia protects against allogeneic transfusion in arthroplasty of the hip but not the knee. This is consistent with what is known about the hemodynamic consequences of spinal anesthesia.     

回收式自体输血与异体输血对机体炎症反应的影响

背景 自体血回输在围术期应用日益广泛.自体血和异体血输注均会对机体的炎症反应产生一定的影响.目的 对两种输血方式后机体炎症因子的变化进行对比,阐述围术期两种输血方式对患者的影响. 内容 异体血在输注过程中产生大量炎症因子,如白细胞介素(interleukin,IL)-2、IL-6、IL-8、IL-10、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)等,引起机体炎症反应,可能是术后并发症的重要原因.自体血在回收、过滤的过程中同样会产生一定量的炎症因子. 趋向 对骨科自体血及异体血应用进行对比,研究两种输血方式对机体炎症反应的影响.     

Immune thrombocytopenia: surgical therapy and predictors of response

We have reviewed 40 patients with immune thrombocytopenia purpura (ITP) to assess current methods of preparation for surgery and to evaluate perioperative complications and response to splenectomy. Twenty-one patients had chronic ITP (greater than 1 year duration) and 19 patients had severe acute thrombocytopenia (platelet counts less than 10,000). A progression of methods of pretreatment was seen in the 10-year period reviewed. Seventeen patients received no treatment before admission for surgery, and 10 of these received platelet transfusions. Seventeen patients received steroids immediately preceding surgery; 16 of these responded and 1 received a platelet transfusion. Recently, 5 patients received intravenous gamma globulin (IgG) preceding surgery with all patients responding and none receiving platelet transfusions. One patient received a combination of steroids and IgG with good response and did not require platelet transfusion. No major postoperative complications occurred (ie, pancreatitis, small bowel obstruction, or sepsis) except for one patient requiring a secondary exploration for an accessory spleen and recurrent thrombocytopenia. Eight patients (20%), 6 with severe ITP and 2 with chronic ITP (5 males and 3 females) developed recurrence of thrombocytopenia following surgery up to 1 1/2 years after splenectomy. These patients all required further medical therapy. Three additional patients (2 chronic and 1 severe) developed thrombocytopenia following viral illnesses, but required no further therapy. Of the 8 surgical failures, 4 failed to respond to prior treatment with steroids, 1 to IgG, and 2 failed to respond to combination therapy, while one surgical failure responded to both steroid and combination therapy. Of the responders to splenectomy (32 patients), only 3 failed to respond to prior treatment with steroids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of blood transfusion and anesthesia on resistance to bacterial peritonitis

Patients who undergo gastrointestinal operations and require prolonged anesthesia or blood transfusions have been reported to have a higher incidence of infectious complications. A rat peritonitis model was used to determine if the increased rate of infection was due to the severity of their underlying disease process or to possible immunosuppressive effects of transfusions and anesthesia. Four hundred adult Lewis rats were divided into four groups. Each group received either 0.5 ml of allogeneic blood, 0.5 ml of syngeneic blood, metaphane anesthesia, or 1.5 ml of saline. They were challenged with either 1 × 10⁸ or 1 × 10⁷, Escherichia coli on the day of transfusion or 4 days after transfusion. Survival rates and mean survival times were determined. Syngeneic transfusions were found not to significantly impair survival. Anesthesia administration resulted in a moderate impairment in survival. Allogeneic blood transfusions caused the most severe impairment with a greater than 50% decrease in survival rates compared to controls in three of the four groups tested. Blood transfusions would thus appear to impair resistance to bacterial infections to an even greater degree than anesthesia. Unnecessary transfusions should therefore be avoided.     

输血不足与输血过量对外科病人的影响

输血是临床常用的治疗手段，合理输血能有效解除病人痛苦、挽救病人生命，而输血不足、输血过多都将对机体产生不利影响，甚至导致严重的、危及生命的并发症。