Background and objective Laboratory stress studies found that acute psychological stresses may elicit changes in leukocyte numbers similar to those occurring in physical stresses. Both types of stress evoke – mainly by release of catecholamines – leukocytosis resulting from a release of natural killer cells (NK-cells), of CD8+ T-cells, of monocytes and of neutrophils. However, there is little proof that laboratory stress models can be applied to daily clinical routines. As a likely inductor of an immunological stress response the setting of retrobulbar anaesthesia prior to intraocular surgery permits the study of a short-term painful anaesthetic procedure under highly standardized conditions. This was examined in 16 female patients.

Methods Counts of leukocyte subsets, serum cortisol and cardiovascular variables were measured 30 min and 1 min prior to retrobulbar anaesthesia as well as 2, 15 and 45 min afterwards.

Results The setting of retrobulbar anaesthesia induced an increase in total leukocytes [+380 cells μL−1; P < 0.01 (means; significance level)] mainly due to rising counts of neutrophils (+241 cells μL−1, P < 0.01). Of all lymphocyte subpopulations, natural killer cells increased most markedly (+64 cells μL−1; P < 0.01). Furthermore, the retrobulbar block induced an increase in systolic arterial pressure (+15.2 mmHg; P < 0.01).

Conclusion These changes in immunological and cardiovascular variables are considered to be elements of a sympatho-adrenal stress reaction; catecholamines are considered to induce a demargination of leukocytes by binding to β2-adrenoceptors and by modifying the avidity state of adhesion molecules.