Effects of anesthesia and operation on the classical pathway of complement activation

Cholecystectomy in a patient with paroxysmal nocturnal haemoglobinuria undergoing ravulizumab maintenance treatment

A 47-year-old male with paroxysmal nocturnal haemoglobinuria (PNH) controlled with routine ravulizumab administration suffered a massive haemolytic crisis due to choledocholithiasis. Laparoscopic cholecystectomy was performed 6 weeks after a regular ravulizumab infusion. After surgery, the patient presented with anaemia without marked elevation in lactate dehydrogenase and required two blood transfusions. Tumour necrosis factor-α increased more than twofold with reticulocyte suppression after surgery, suggesting the involvement of myelosuppressive cytokines. This case suggests that laparoscopic surgery may be safely performed in patients with PNH receiving ravulizumab maintenance treatment. However, attention should be paid to postoperative anaemia, regardless of breakthrough haemolysis.

An IgG-induced neutrophil activation pathway contributes to human drug-induced anaphylaxis

Anaphylaxis is a systemic acute hypersensitivity reaction that is considered to depend on allergen-specific immunoglobulin E (IgE) antibodies and histamine release by mast cells and basophils. Nevertheless, allergen-specific IgG antibodies have been proposed to contribute when the allergen is an abundant circulating large molecule, e.g., after infusions of therapeutic antibodies or dextran. Data from animal models demonstrate a pathway involving platelet-activating factor (PAF) release by monocytes/macrophages and neutrophils activated via their Fc gamma receptors (FcγRs). We hypothesized that such a pathway may also apply to small drugs and could be responsible for non–IgE-mediated anaphylaxis and influence anaphylaxis severity in humans. We prospectively conducted a multicentric study of 86 patients with suspected anaphylaxis to neuromuscular-blocking agents (NMBAs) during general anesthesia and 86 matched controls. We found that concentrations of anti-NMBA IgG and markers of FcγR activation, PAF release, and neutrophil activation correlated with anaphylaxis severity. Neutrophils underwent degranulation and NETosis early after anaphylaxis onset, and plasma-purified anti-NMBA IgG triggered neutrophil activation ex vivo in the presence of NMBA. Neutrophil activation could also be observed in patients lacking evidence of classical IgE-dependent anaphylaxis. This study supports the existence of an IgG-neutrophil pathway in human NMBA-induced anaphylaxis, which may aggravate anaphylaxis in combination with the IgE pathway or underlie anaphylaxis in the absence of specific IgE. These results reconcile clinical and experimental data on the role of antibody classes in anaphylaxis and could inform diagnostic approaches to NMBA-induced acute hypersensitivity reactions.

Hemolytic reaction in the washed salvaged blood of a patient with paroxysmal nocturnal hemoglobinuria

Background

In patients with paroxysmal nocturnal hemoglobinuria (PNH), the membrane-attack complex (MAC) formed on red blood cells (RBCs) causes hemolysis due to the patient’s own activated complement system by an infection, inflammation, or surgical stress. The efficacy of transfusion therapy for patients with PNH has been documented, but no studies have focused on the perioperative use of salvaged autologous blood in patients with PNH.

Case presentation

A 71-year-old man underwent total hip replacement surgery. An autologous blood salvage device was put in place due to the large bleeding volume and the existence of an irregular antibody. The potassium concentration in the transfer bag of salvaged RBCs after the wash process was high at 6.2 mmol/L, although the washing generally removes > 90% of the potassium from the blood. This may have been caused by continued hemolysis even after the wash process. Once activated, the complement in patients with PNH forms the MAC on the RBCs, and the hemolytic reaction may not be stopped even with RBC washing.

Conclusions

Packed RBCs, instead of salvaged autologous RBCs, should be used for transfusions in patients with PNH. The use of salvaged autologous RBCs in patients with PNH should be limited to critical situations, such as massive bleeding. Physicians should note that the hemolytic reaction may be present inside the transfer bag even after the wash process.

The management of Cesarean delivery in a parturient with paroxysmal nocturnal hemoglobinuria complicated by severe preeclampsia

PURPOSE

To describe the anesthetic and peripartum management of a parturient with paroxysmal nocturnal hemoglobinuria complicated by severe preeclampsia, review the pathophysiology of this condition, rationale for thromboembolic prophylaxis, and its implications on the choice of labour analgesia and anesthesia.

CLINICAL FEATURES

A 35-yr-old primigravida was diagnosed with paroxysmal nocturnal hemoglobinuria at 18 weeks gestation following new onset pancytopenia. Venous thromboembolic prophylaxis with low molecular weight heparin (LMWH) was started, and continued despite a persistent thrombocytopenia. At 34 weeks, labour was induced after she developed signs of severe preeclampsia, and intravenous magnesium sulfate therapy was commenced. The use of a twice daily dosing regime of LMWH, along with severe thrombocytopenia contraindicated neuraxial anesthesia. As a result, labour analgesia was provided with an intravenous patient-controlled analgesia system with fentanyl. The patient subsequently had an uneventful Cesarean delivery under general anesthesia. Anticoagulation with LMWH was restarted postoperatively, and continued for six weeks postpartum. She was discharged home on day 20 postpartum, on oral prednisolone under the care of the hematologists.

CONCLUSION

Paroxysmal nocturnal hemoglobinuria is associated with an increased risk of venous thromboembolism, and so anticoagulation therapy assumes primary importance. The use of LMWH for prophylaxis in combination with thrombocytopenia may contraindicate neuraxial anesthesia. General anesthesia should be aimed at preventing or exacerbating complement mediated intravascular hemolysis.

The anesthetic management of a patient with paroxysmal nocturnal hemoglobinuria

IMPLICATIONS

This case report describes the anesthetic considerations for a patient with paroxysmal nocturnal hemoglobinuria. Specific strategies to be applied in the perioperative period to prevent hemolytic episodes and venous thrombosis are also discussed.

Alterations in the course of acid-induced lung injury in rats after general anesthesia: volatile anesthetics versus ketamine

Pulmonary aspiration of gastric acid is a complication that occurs during anesthesia. The effects of the often used anesthetics on the inflammatory response after aspiration of acid are not known. We examined the effects of three different inhaled anesthetics--halothane, enflurane, and isoflurane--as well as parenteral ketamine, on the associated immediate mortality, alveolar protein leakage, and morphometric changes after intrapulmonary instillation of acidic solution in rats. Animals in deep state of anesthesia had a higher mortality after the instillation of acidic solutions than those in lighter stages (82.5% vs 31.6%). Protein leakage over 5 h was greater in the animals receiving volatile anesthetics (range 0.9-1.2) compared with those receiving ketamine (0.6 +/- 0.05). Desferoxamine did not decrease protein leakage in acid-injured animals (1.1 +/- 0.06 vs 1.02 +/- 0.08). Furthermore, volatile anesthetics resulted in an increase in the acute inflammatory response and leukocytic infiltration compared with ketamine in acid-injured lungs. We conclude that the administration of inhaled anesthetics was associated with exacerbation of an acute inflammatory response after aspiration of acidic solution. Lung injury was not increased with ketamine anesthesia. This difference was the result of the hypotensive effects of inhaled anesthetics.

IMPLICATIONS

This study reveals that the use of inhaled anesthetics aggravates inflammation secondary to gastric aspiration and should be avoided on diagnosis of the situation.

Perioperative complement activation in neonates under halothane or fentanyl anaesthesia

We investigated perioperative changes in complement activation in 18 neonates undergoing elective abdominal surgery with or without thoracotomy by measuring plasma concentrations of C3a and C5a, and leucocyte counts in peripheral blood. The 18 neonates, ranging in age from 1 to 17 days, were randomly divided into two groups according to type of anaesthetic procedures; the "halothane group" consisted of nine neonates in whom general anaesthesia was maintained with halothane and nitrous oxide (N2O) in oxygen, while the "fentanyl group" consisted of nine neonates in whom general anaesthesia was maintained with fentanyl and N2O in oxygen. Plasma C3a and C5a concentrations were higher in the fentanyl group than in the halothane group during the perioperative period. We have demonstrated that abdominal surgical trauma caused complement activation even in neonates undergoing the fentanyl rather than the halothane anaesthesia. Further studies are required to elucidate the precise mechanisms and the clinical implication of perioperative complement activation in neonates.

Effects of anaesthesia and surgery on the immune response

Alterations have been found to occur in every component of immune response during anaesthesia and surgery. These alterations represent the body's general physiological responses and are mainly dependent on the extent of surgery, as well as other factors such as the patient's age and health status, medication and blood transfusion. Anaesthetic and operative complications have profound effects on these responses. Basically, the immune response to anaesthesia and surgery is a beneficial reaction, needed in local host defences and wound healing and in preventing the body from making autoantibodies against its own tissues. The responses may, however, contribute to the development of postoperative infections and spread of malignant disease. During uncomplicated conventional surgery, the immune response usually passes clinically unnoticed without any harmful effects. Absent responses and excessively high responses, on the other hand, harm the patient. Our understanding of immunological phenomena and our possibilities of controlling mediator activation are now lagging behind the technical advances made in operative treatment. If we want to decrease operative morbidity and mortality to below their present levels, more attention should be directed to immune responses to major surgery, injuries and operative complications with massive mediator release which place the surgical patient at risk. Experimental evidence suggests that results of treatment in injured and operated patients can in the future be improved by controlling immune responses and their mediator systems. Our current level of knowledge of immune responses is already helping us to avoid many immune-mediated complications. However, routine interference with these responses is not indicated.

Percutaneous transluminal coronary angioplasty in a patient with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PHN) is an acquired chronic hemolytic anemia associated with an unusual susceptibility to hemolytic crisis, infection, and venous thrombosis which would be aggravated by a number of factors including surgery. We report a case of PHN undergoing percutaneous transluminal coronary angioplasty and discuss the corresponding perioperative management.

Paroxysmal nocturnal haemoglobinuria. Peri-operative management of a patient with Budd-Chiari syndrome

The peri-operative management of a patient with paroxysmal nocturnal haemoglobinuria and associated hypoplastic anaemia, who underwent successful elective surgery for the complication of Budd-Chiari syndrome, is described. Anaesthesia in patients with paroxysmal nocturnal haemoglobinuria should be based on drugs and materials least likely to cause complement activation. The reasons for use of a technique based on benzodiazepines, opioids, isoflurane and the avoidance of nitrous oxide are discussed.