Sex and surgical stress

Corticosterone binding globulin regulation and thymus changes after thermal injury in mice

Thermal injury is extremely stressful, and data characterizing the systemic endocrine stress response to this injury are sparse. The objective of this study was to measure the effects of thermal injury on mice on corticosterone (Cort) levels in relation with corticosteroid-binding globulin (CBG) and thymus cell populations. The endocrine stress response was determined by measuring total Cort, free Cort, CBG binding capacity, liver CBG mRNA, and circulating CBG levels at 1, 2, 5, and 10 days postburn. Thymus cell populations were also analyzed. After thermal injury, a rapid increase of total Cort was observed in the first 48 h. This was associated with a decrease of hepatic CBG mRNA, protein levels, and binding capacity. Percentage of free Cort in the burn group peaked at day 2 postburn with a dramatic (+500%) increase. This correlated with a significant decrease of thymus cellularity (50% less). Phenotypic analyses showed that corticosensitive cells were significantly altered. After treatment (5 days), both endocrine and immune parameters returned to control levels. Our results demonstrate that, after a thermal injury, CBG is mainly responsible for Cort's action on corticosensitive immune cells.

Perioperative stress response to carotid endarterectomy: The impact of anesthetic modality

OBJECTIVE

Surgery for extracranial carotid artery disease has been challenged by carotid angioplasty stenting because the latter is less invasive and avoids surgical trauma. In fact, the magnitude of the perioperative stress response evoked by carotid endarterectomy (CEA) has never been evaluated. Our aim was to determine the degree of surgical trauma caused by CEA and to define differences related to the use of locoregional or general anesthesia.

METHODS

We prospectively studied 113 consecutive CEAs performed on 109 patients admitted at a community institutional center. Patients were stratified for demographics and risk factors and operated on under locoregional (LA) or general anesthesia (GA) depending on both the surgeon preference and patient's compliance. Selective carotid shunting was performed for patients who manifested neurologic deficits under LA or had stump pressure values </=30 mm Hg under GA. Markers of the stress response, including cortisol, adrenocorticotropic hormone, prolactin, and C-reactive protein, were measured intraoperatively, before and after carotid artery cross-clamping (CACC), and postoperatively up to the third day after surgery. Hemodynamic variability was assessed during surgery and for 24 hours postoperatively. Operative times were also measured. Surgeons were considered as independent variables for stress response. Statistics were run by means of nonparametric tests and univariate and multivariate analysis with a linear regression model.

RESULTS

CEA was performed under GA in 63 cases (55.8%) and under LA in 50 (44.2%). The two groups were comparable in terms of demographics and risk factors. Intraoperatively, cortisol and adrenocorticotropic hormone levels were significantly higher in the LA group (both P <.001). CACC increased the intraoperative cortisol levels in both the GA (P =.019) and the LA groups (P =.006). However, in patients who underwent carotid shunting, this effect was abolished (GA group, P =.779; LA group, P = 1.0). During the early postoperative period there was no difference between the two groups. On postoperative day 1 the stress response was abolished in both groups. Prolactin levels increased intraoperatively in both the LA and GA groups and returned within preoperative values on postoperative day 1. Prolactin levels were higher in the GA group (P =.003 intraoperatively and P <.001 postoperatively). C-reactive protein significantly increased in both GA and LA groups on postoperative days 1 and 2 and started to decrease on day 3 with no differences between the two groups at any time. Hemodynamic variability and considered risk factors including individual surgeon were not significant variables. Gender-related differences were found only in prolactin secretion. The length of surgery had an impact for procedures that lasted >120 minutes. Three patients experienced an intraoperative neurologic event and had higher post-CACC cortisol values as compared to asymptomatic patients.

CONCLUSIONS

Intraoperative surgical stress was higher under LA and was blunted by carotid shunting under both LA and GA. Within 2 hours after surgery the anesthetic modality no longer had any impact on surgical trauma. The stress response to CEA, regardless of the type of anesthesia, was abolished within 24 hours. Intraoperative stress response, namely hypercortisolemia, directly correlated with subclinical and clinical cerebral hypoperfusion/ischemia during CACC. Hence, attenuation of the stress response to CEA might decrease the incidence of cerebral ischemic events.

Cardiovascular, biochemical, and hormonal responses to intravenous sedation with local analgesia versus general anesthesia in patients undergoing oral surgery

The effects of intravenous conscious sedation and general anesthesia on a number of stress variables were compared in healthy patients undergoing oral surgery. In the intravenous sedation group only the levels of plasma growth hormone and prolactin rose significantly. In the general anesthesia group significant rises were seen in heart rate; systolic blood pressure; mean arterial pressure; levels of plasma adrenaline, adrenocorticotropic hormone, cortisol, and prolactin; and levels of blood glucose, all indicative of a stress response. This study demonstrates that oral surgery under intravenous conscious sedation with local analgesia is associated with less patient stress than is oral surgery under general anesthesia.

Endocrine and metabolic responses after standardized moderate surgical trauma: influence of age and sex

The endocrine and metabolic responses to elective cholecystectomy and the influence of age and sex on this stress response were investigated in 21 patients, eight men and 13 women. The patients were divided into two groups, older (n=10) and younger (n=11) than 55 years respectively. Arterial plasma concentrations of catecholamines, cortisol and free fatty acids as well as serum insulin and arterial blood concentrations of glucose, lactate, glycerol, alanine and 3-hydroxybutyrate were measured preoperatively and 2, 24, 48, 72 and 96 h after the start of surgery. Oxygen uptake and CO2 production were measured and respiratory quotient (RQ) was calculated. All hormones and metabolites except insulin and alanine were significantly elevated immediately after surgery. At 24 h plasma noradrenaline and blood glucose were still significantly increased. Serum insulin was increased at 24 and 48 h. Oxygen uptake and plasma cortisol were significantly elevated throughout the period studied and blood alanine was decreased from 2 to 72 h after surgery. The older group showed a significantly higher increase in noradrenaline and lactate, whereas women preoperatively as well as postoperatively had higher glycerol levels. At the end of the period studied women had higher FFA-levels. We conclude that cholecystectomy evokes a significant endocrine and metabolic response and that some of the variables studied are still significantly altered up to 4 days postoperatively. The influence of age and sex on this stress response is of minor importance.

Peri-operative endocrine effects of etomidate

This study investigated the effects of etomidate on endocrine responses to anaesthesia and surgery. Patients undergoing abdominal hysterectomy received standard anaesthetics of either etomidate for induction with etomidate infusion, or thiopentone and halothane. Etomidate suppressed the secretion of cortisol and aldosterone for between 8 and 22 hours after the end of the etomidate infusion; 11-deoxycortisol secretion was not suppressed during the etomidate infusion, but rose postoperatively; 17 alpha-hydroxyprogesterone suppression also lasted only as long as the etomidate infusion. There were no effects on plasma oestradiol, ACTH, or prolactin, but growth hormone concentrations were elevated in the etomidate group. Etomidate was concluded to have influenced adrenocortical function only, where it probably inhibits 11 beta-hydroxylation, 17 alpha-hydroxylation and other intramitochondrial hydroxylation reactions. There were no clinical sequelae attributable to adrenocortical suppression. The relationship of chemical structure of etomidate and other phenylated imidazoles to inhibition of steroidogenesis is discussed.

Increased cortisol excretion in chronic pain

Urine samples were collected from 67 patients attending a Regional Pain Unit for treatment of chronic pain. Patients treated with steroids or with any signs or symptoms of Cushing's syndrome were excluded. The urine cortisol creatinine ratio was subsequently measured. Values for the urine cortisol/creatinine ratio were elevated in 31% of the patients, and grossly elevated in some. These patients could not be differentiated from those with normal ratios on the basis of pain or mood scores, cause of pain or drug therapy; they tended to have pain of shorter duration. Possible interpretations of these results are discussed.