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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1978-6-28
pubmed:abstractText
The effects on metabolism and red cell function of blood levels of thiocyanate (SCN-) and cyanide (CN-) were studied in 42 patients undergoing surgery under controlled hypotension (CH) induced by sodium nitroprusside (SNP). The mean dosage of SNP administered was 21.38 mg (SD = 12). The durating of perfusion was 121 minutes (SD = 11). All operations were performed under neuroleptanalgesia without complications. No tachyphylaxis was encountered. Under SNP a slight increase of blood SCN- (from 13.9 mg/l +/- 1.1 to 23 mg/l +/- 2.6) was found. Blood levels of CN- are increased mostly in the red cell, the mean value being 0.300 mg/l +/- 0.10 for whole blood after two hours of perfusion. This value decreased when perfusion was stopped. All blood samples were negative for methaemoglobin and cyanmethaemoglobin. Carbonic anhydrase activity was not modified, CN- toxicity levels for this enzyme being 50 times higher than those found during our study. 2,3-DPG levels did not vary. Blood gases, acid-base balance and Davo2 did not change significantly, although a slight increase in blood lactate was measured. As shown by this study, appreciable amounts of CN- are detected in blood during SNP perfusion while SCN- stays at relatively low levels. Fortunately most of the CN- released from SNP moves into the red cell and does not alter its functions at clinical concentrations. The low plasma concentration of CN- is not sufficient to cause important metabolic disturbances. However, dosages of SNP higher than those administered during this study could increase the blood and tissue CN- to toxic levels. A toxicity study shows that, during a relatively short period of time, SNP dosage should not exceed 1.16 mg/kg or a maximum of 10 microgram/kg/min for a period of two hours.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0008-2856
pubmed:author
pubmed:issnType
Print
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
92-105
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1978
pubmed:articleTitle
Nitroprusside, its metabolites and red cell function.
pubmed:publicationType
Journal Article