Detection and evaluation of persisting stress-induced hormonal disturbances by a post stress provocation test in humans

Stress during simulated emergency transportation in a rescue helicopter: cross-correlation between stress hormones, vital functions and subjective well-being

Vital functions and stress hormone levels during simulated emergency helicopter transport in healthy volunteers. Twenty-three volunteers were subjected to a simulated 15 minute rescue helicopter transport. We determined vital functions, ACTH, cortisol and prolactin during the flight and filled in a standardized questionnaire before and after the flight. Data were analysed descriptively, by means of cross tabulation, Spearman rank correlation and cross-correlation technique. During take-off we recorded a significant increase of vital parameters such as heart rate. Prolactin concentration rose slightly after the start. Maximum cortisol and ACTH levels were found before take-off and then they decreased gradually. As expected, ACTH and cortisol cross-correlated significantly without any relevant time lag. Test items showed a feeling of fear and concern before take off. After the flight the volunteers reported having less stress than expected. Particularly, diastolic blood pressure and prolactin levels were markedly associated with questionnaire items such as behaviour of the staff or nausea. Heart rate significantly correlated with anxiety scores. Helicopter transportation induced a marked stress reaction in healthy volunteers, which speaks in favour of smooth transports in modern helicopters and adequate behaviour towards the patient of the staff.

Interdependency of the oxidizability of lipoproteins and peroxidase activity with base excess, HCO3, pH and magnesium in human venous and capillary blood

As continuous production of free radicals and reactive oxygen species is a normal metabolic process, increased metabolism during exercise/workload should increase free radical generation and oxidative stress. Oxidative stress intensity should then depend on the intensity of metabolic stress effects. Intensity of stress is usually reflected in norepinephrine (NE) levels, which correlate linearly and significantly with changes in blood gases, blood buffer systems, blood electrolytes, blood glucose and lactate [Porta, S., Leitner, G., Heidinger, D., Lang, T., Weiss, U., Smolle, K.H., Hasiba, K., 1997. Magnesium während der Alpinausbildung bringt um 30% bessere Energieverwertung. Magnesium-Bulletin 19(2), 59-61]. Those parameters were used in an open study design to screen 64 subjects for metabolic stress effects along with their antioxidative capacity using both venous and capillary blood. To compare venous and capillary blood, we took venous blood samples from 12 healthy volunteers and capillary blood from 52 other healthy subjects. To show whether free radical changes indeed go along with metabolic stress effects, we tried to quantify relations between metabolic stress effects and oxidative stress by linear correlations. In conclusion, both venous and capillary blood are suitable for determining at least those parameters of the oxidative state that we used. All significant correlations of peroxidase activity and oxidation lag time (OLT) with pH, bicarbonate (HCO3), base excess (BE) and magnesium (Mg) indicate that free radical production increases with metabolism. Those relationships could help to evaluate the oxidative state more precisely.

Emergency medical service transport-induced stress? An experimental approach with healthy volunteers

This randomized controlled trial was designed to evaluate the effects of simulated emergency medical service (EMS) transport related stress on hemodynamic variables, and catecholamine plasma levels. A total of 32 healthy male volunteers were randomized to being carried by paramedics from a third-floor apartment through a staircase with subsequent high-speed EMS transport with lights and sirens (stress; n = 16); or sitting on a chair for 5 min, and lying on a stretcher for 15 min (control; n = 16). Blood samples and hemodynamic variables were taken in the apartment before transfer, at the ground floor, and at the end of EMS transport in the stress group, and at corresponding time points in the control group. The stress versus control group had both significantly (P < 0.05) higher mean +/- SEM epinephrine (71 +/- 7 versus 37 +/- 3 pg/ml), and norepinephrine (397 +/- 29 versus 299 +/- 28 pg/ml) plasma levels after transport through the staircase. After EMS transport, the stress versus control group had significantly higher epinephrine (48 +/-6 versus 32 +/- 2 pg/ml), but not norepinephrine (214 +/- 20 versus 264 +/- 31 pg/ml) plasma levels. Heart rate increased significantly from 72 +/- 2 to 84 +/- 3 bpm after staircase transport, but not during and after EMS transport. In conclusion, volunteers being carried by paramedics through a staircase had a significant discharge of both epinephrine and norepinephrine resulting in increased heart rate, but only elevated epinephrine plasma levels during EMS transport. Transport through a staircase may reflect more stress than emergency EMS transport.

Liver ischemia, catecholamines and preoperative condition influencing postoperative tachycardia in liver surgery

The aim of our study was to assess the influence of intraoperative hypoxic stress -unavoidably brought about by so called Pringle maneuver - on free and conjugated catecholamines during major hepatic resection. Judging from earlier results of fatigue-experiments in rats we also wanted to check the relationship between of poor general preoperative condition and conspicuously low triglyceride serum concentrations. The study included 26 patients with primary and secondary liver tumors. The mean age was 54 years (range 27-79). Twenty-one patients had segmental liver resections, 3 had hemihepatectomies and 2 hydatid cysts were treated by cystectomy. Blood samples were taken 2 days before and throughout surgery. Catecholamine plasma values were determined by high performance liquid chromatography. Statistical comparisons were made by t-test, ANOVA and chi square test. Free plasma catecholamines increased significantly during prolonged intraoperative ischemia (Pringle time 50-125 minutes). Patients with elevated intraoperative catecholamines had a significant correlation to postoperative episodes of tachycardia, and prolonged hospital stay. On the other hand, we could also see postoperative tachycardias in patients with short Pringle times (18-49 minutes) but with decreased preoperative serum triglycerides as an indicator of chronic stress and reduced general condition. Intraoperative hypoxic stress is associated with increased catecholamine values. Elevated catecholamines may well cause postoperative sinus-tachycardias (mean 20 hours) and are strongly related to postoperative liver failure and prolonged hospital stay.

Temporary increase of plasma epinephrine affects stress responses 24 h later

The impact of temporary (24 h) implantation of epinephrine tables on catecholamine responses to handling and immobilization 24 h later was investigated in rats. Free plasma epinephrine responded with an increase to both types of stress (77% and 326%, respectively) while controls showed a weaker response to immobilization. The basal level of free plasma norepinephrine was reduced (46% vs. controls) after epinephrine pretreatment, but neither handling nor immobilization had a specific effect on this parameter. In contrast, the basal level of free plasma dopamine was increased after epinephrine pretreatment (183%); however, as with free norepinephrine, there was no specific effect of handling or immobilization. Conjugated plasma epinephrine was significantly lowered after epinephrine pretreatment (44% vs. controls). It did not respond specifically to handling or immobilization except for a stronger response after 20 min of immobilization. Conjugated norepinephrine showed no specific response, but increased nonspecifically after extended immobilization. Conjugated dopamine was lowered (30%-48%) in the E-treated group and did not respond to stress at any time. Thus, a temporary elevation of free plasma epinephrine affected, differentially, basal levels and stress responses of free and conjugated catecholamines 24 h later.