[Pathophysiologic and anesthesiologic characteristics of patients with leukemia]

Leukaemia and its associated therapy result in pathophysiological peculiarities relevant to anaesthesia. Leukaemic patients suffer from anaemia, coagulation disorders, and the consequences of immunosuppression. In addition, some patients show infiltrations of the oropharynx, potentially resulting in difficult intubation and/or pharyngeal haemorrhage. Mediastinal masses can induce complete airway obstruction during general anaesthesia. Patients with a white blood cell count (WBC) greater than 100,000/mm3 (hyperleukocytosis) can suffer from the leukostasis syndrome with acute respiratory failure as well as cerebral vascular occlusions and bleeding due to increased blood viscosity and disturbed microvascular perfusion. Since this syndrome may be triggered by surgery, the WBC should be reduced prior to general anaesthesia in patients with hyperleukocytosis. To avoid development of the leukostasis syndrome, transfusion of packed red cells should be restricted in these patients. Hyperleukocytosis can simulate in-vitro hypoxaemia due to the excessive oxygen consumption of the mass of leukaemic blood cells during routine blood gas analysis. Therapy of leukaemia can lead to the tumor-lysis syndrome with hyperuricaemia, hyperphosphataemia, hyperkalaemia, hypocalcaemia, and hypoglycaemia, and may induce acute renal failure. Since drug interactions have only been evaluated for the combination of two or three drugs, interactions of cytotoxic agents with anaesthetics can hardly be predicted because of the large number of drugs simultaneously administered to leukaemic patients. The heart and lungs are target organs for the acute or chronic side effects of cytotoxic drugs, resulting in non-cardiogenic pulmonary oedema (e.g., cytosine-arabinoside), lung fibrosis (e.g., bleomycin), or arrhythmias and cardiac failure (e.g., adriamycin). The severity of these side effects depends on pre-existing organ disease and only in part on drug dosage. Only HLA- and CMV-compatible blood components should be administered to leukaemic patients. Hyperleukocytosis and the first days of cytotoxic treatment represent relative contraindications to general anaesthesia.