[Lymphocyte subpopulations in controlled hypotension with sodium nitroprusside].
OBJECTIVE
Induced hypotension is an anaesthesiological method to reduce blood loss in surgical patients. The aim of this study was to investigate whether induced hypotension with sodium nitroprusside (SNP) causes changes in lymphocyte subpopulations.


METHODS
In a prospective randomised evaluation 30 patients undergoing elective oto-rhino-laryngological interventions were studied. In 15 patients SNP was administered to reduce the mean arterial pressure to 50 mmHg. There was a control group of another 15 patients. Anaesthesia was induced with etomidate and maintained with isoflurane. At 7 a.m. on the day of operation (T1), 10 minutes after induction of anaesthesia (T2), 60 minutes after T2 (T3, end of SNP-infusion), 120 minutes (T4) after T2; 180 minutes (T5) after T2, and at 7 a.m. on the following morning (T6) blood samples were taken. A new method (whole blood) was used to mark 6 different lymphocyte subpopulations with monoclonal antibodies which were measured by flow cytometry.


RESULTS
In both groups a significant decrease in total lymphocyte count (from 32.7 x 10(9) cells/l preoperatively to 13 x 10(9) cells/l the following morning in the SNP-group and from 31 x 10(9) cells/l to 14.2 x 10(9) cells/l the following morning in the control group) was observed. In the SNP-group the HLA-DR positive T-lymphocytes increased from 11.8% at T1 to 19.2% at T5 and 22.3% at T6. No statistically significant changes were found in percentage of T-, T4-, T8-, B-lymphocytes and natural killer cells.


CONCLUSIONS
The increase in the percentage of activated T-lymphocytes is possibly due to an activation of the sympatho-adrenergic system after sodium nitroprusside-infusion and a subsequent redistribution of these cells from other organs (bone marrow, spleen, lymph nodes). The cell-mediated and the humoral immunity are not altered by induced hypotension. In discussing this result, the age of the patients, the extent of the surgical trauma, the anaesthesiological procedure and the methodological aspects in the lymphocyte assay should be taken into consideration.
Heesen
M
M
Abteilung Anaesthesiologie und Operative Intensivmedizin am Klinikum, Justus-Liebig-Universität Giessen.
Dietrich
G V
GV
Eistert
B
B
Kulozik
U
U
Boldt
J
J
Glanz
H
H
Hempelmann
G
G
D000293:Adolescent; D000768:Anesthesia, General; D005045:Etomidate; D005260:Female; D006801:Humans; D007023:Hypotension, Controlled; D007530:Isoflurane; D007958:Leukocyte Count / Q000187:drug effects; D016131:Lymphocyte Subsets / Q000187:drug effects* / Q000276:immunology; D008297:Male; D009599:Nitroprusside / Q000008:administration & dosage / Q000009:adverse effects*; D010038:Otorhinolaryngologic Diseases / Q000276:immunology / Q000601:surgery
D009599:Nitroprusside; D007530:Isoflurane; D005045:Etomidate
Untersuchung über Lymphozyten-Subpopulationen unter kontrollierter Hypotension mit Nitroprussidnatrium.