This study found no causal relationship between cerebral hypoxia and low blood pressure and POCD. Age, duration of anaesthesia, introperative complications, and postoperative infections were found to be associated with POCD. POCD is just as likely to occur after operations under regional anesthesia as under general anesthesia. More likely after major operations than minor operations. More likely after heart operations than other types of surgery. More likely in aged than in younger patients. More likely in older patients with high alcohol intake. People with higher preoperative ASA physical status scores are more likely to develop POCD. People with lower educational level are more likely to develop POCD than those with a higher educational level. People with prior history of a stroke, even though there is complete functional recovery, are more likely to develop POCD. More likely in the elderly with pre-existing declining mental functions, termed mild cognitive impairment (MCI). MCI is a transitional zone between normal mental function and evident Alzheimers disease or other forms of dementia. It is insidious, and seldom recognized, except in retrospect after affected persons are evidently demented. Delirium and severe worsening of mental function is very likely in those with clinically evident Alzheimers disease or other forms of dementia, as well as those with a history of delirium after previous operations. Footnotes
Further reading
"Postoperative cognitive dysfunction" (PDF). {{cite journal}}: Cite journal requires |journal= (help)
Muñoz-Corsini L, Gómez-Arnau J, Porras MC, Galindo S, Jiménez R (May 1997). "Postoperative cognitive dysfunction". Rev Esp Anestesiol Reanim. 44 (5): 191–200. PMID 9280997. Crosby, Gregory; Culley, Deborah J.
Monoclonal gammopathy, also known as paraproteinemia, is the presence of excessive amounts of myeloma protein or monoclonal gamma globulin in the blood. It is usually due to an underlying immunoproliferative disorder or hematologic neoplasms, especially multiple myeloma. It is sometimes considered equivalent to plasma cell dyscrasia. The most common form of the disease is monoclonal gammopathy of undetermined significance. Causes
Causes of paraproteinemia include the following:
Leukemias and lymphomas of various types, but usually B-cell non-Hodgkin lymphomas with a plasma cell component. Myeloma
Plasmacytoma
Lymphoplasmacytic lymphoma
Idiopathic (no discernible cause): some of these will be revealed as leukemias or lymphomas over the years. AL amyloidosis

Diagnosis
These are characterized by the presence of any abnormal protein that is involved in the immune system, which are most often immunoglobulins and are associated with the clonal proliferation of lymphocytes.When a paraproteinemia is present in the blood, there will be a narrow band, or spike, in the serum protein electrophoresis because there will be an excess of production of one protein.There are two large classes of blood proteins: albumin and globulin. They are generally equal in proportion, but albumin is much smaller than globulin, and slightly negatively charged, which leads to an accumulation at the end of the electrophoretic gel. The globulins separate out into three regions on the electrophoretic gel, which are the α band, the β band, and the γ band. The α band can be separated into two components: α1 and α2. The α1 region consists mostly of α1-antitrypsin and α1-acid glycoprotein. The α2 region is mostly haptoglobin, α2-macroglobulin, α2-antiplasmin, and ceruloplasmin.