Stress doses of hydrocortisone reverse hyperdynamic septic shock: a prospective, randomized, double-blind, single-center study

OBJECTIVE

To investigate the effects of stress doses of hydrocortisone on the duration of vasopressor therapy in human septic shock.

DESIGN

Prospective, randomized, double-blind, single-center study.

SETTING

Twenty-bed multidisciplinary intensive care unit in a 1400-bed university hospital.

PATIENTS

Forty consecutive patients who met the ACCP/SCCM criteria for septic shock. An additional criterion for inclusion in the study was vasopressor support and high-output circulatory failure with a cardiac index of >4 L/min/m2 after fluid resuscitation (pulmonary capillary wedge pressure: 12-15 mm Hg) and without the use of positive inotropes such as dobutamine or dopexamine. The primary study end point was the time to cessation of vasopressor support (norepinephrine or epinephrine in any dose, dopamine > or = 6 microg/kg/min). Secondary study end points were the evolution of hemodynamics and the multiple organ dysfunction syndrome (MODS). The severity of illness at recruitment was graded using the Acute Physiology and Chronic Health Evaluation II and the Simplified Acute Physiology Score II scoring systems. MODS was described by the Sepsis-related Organ Failure Assessment score.

INTERVENTIONS

All eligible patients were prospectively randomized to receive either stress doses of hydrocortisone or placebo. Hydrocortisone was started with a loading dose of 100 mg given within 30 mins and followed by a continuous infusion of 0.18 mg/ kg/hr. When septic shock had been reversed, the dose of hydrocortisone was reduced to 0.08 mg/kg/hr. This dose was kept constant for 6 days. As soon as the underlying infection had been treated successfully or sodium serum concentrations had increased to >155 mmol/L, the hydrocortisone infusion was tapered in steps of 24 mg/day. Physiologic saline solution was the placebo.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic and oxygen-derived variables were measured at previously defined time points over a study period of 5 days. Relevant clinical and laboratory measurements were registered for a study period of 14 days to assess the evolution of organ dysfunction. Baseline data at recruitment did not differ between the two groups. Shock reversal was achieved in 18 of the 20 patients treated with hydrocortisone vs. 16 of the 20 patients treated with placebo. Hydrocortisone significantly reduced the time to cessation of vasopressor support. The median time of vasopressor support was 2 days (1st and 3rd Quartiles, 1 and 6 days) in the hydrocortisone-treated group and 7 days (1st and 3rd Quartiles, 3 and 19 days) in the placebo group (p = .005 Breslow test). There was a trend to earlier resolution of the organ dysfunction syndrome in the hydrocortisone group.

CONCLUSIONS

Infusion of stress doses of hydrocortisone reduced the time to cessation of vasopressor therapy in human septic shock. This was associated with a trend to earlier resolution of sepsis-induced organ dysfunctions. Overall shock reversal and mortality were not significantly different between the groups in this low-sized single-center study.

Health-related quality of life and posttraumatic stress disorder in survivors of the acute respiratory distress syndrome

OBJECTIVES

Despite considerable progress in intensive care management of the acute respiratory distress syndrome (ARDS), little is known about health-related quality of life in long-term survivors. In addition, intensive care treatment can be extremely stressful, and many survivors of ARDS report adverse experiences such as respiratory distress, anxiety, or pain during intensive care unit (ICU) treatment. This study was performed to assess health-related quality of life in survivors of ARDS and to test the hypothesis that adverse experiences during ICU treatment result in posttraumatic stress disorder (PTSD) and negative effects on health-related quality of life.

DESIGN

Retrospective, cohort, case-controlled analyses.

SETTING

A 12-bed multidisciplinary ICU of a tertiary care university hospital, capable of providing extracorporeal life support for adults with severe ARDS.

PATIENTS

We studied 80 patients who were admitted to our hospital from 1985 to 1995 and who survived an episode of ARDS. ARDS was defined according to the criteria of the American-European Consensus Conference on ARDS.

INTERVENTIONS

Health-related quality of life was measured using the Health Status Questionnaire of the self-administered Medical Outcomes Study Short Form Survey that consists of 36 questions (SF-36) and the German version of the Post Traumatic Stress Syndrome 10-Questions Inventory (PTSS-10), a self-report scale for the diagnosis of posttraumatic stress disorder based on the Diagnostic and Statistical Manual (Third Edition) criteria (American Psychiatric Association). The number of adverse experiences (anxiety, respiratory distress, pain, and nightmares) during intensive care was evaluated by means of a structured questionnaire. For each patient with ARDS, three age- and gender-comparable controls were randomly selected from databases providing normal values for the SF-36 and PTSS-10 scores in populations at risk for posttraumatic stress disorder.

MEASUREMENTS AND MAIN RESULTS

Survivors of ARDS showed statistically significant impairments in all eight health dimensions of the SF-36 when compared with normal controls (median reduction 21.3%, p < .006) with maximal impairments in physical function (median reduction 28.9%, p = .000) and a 38% higher frequency of chronic pain (p = .0001). Three of 34 patients reporting none, or one, adverse experience had evidence of posttraumatic stress disorder vs. 19 of 46 patients remembering multiple traumatic episodes (p = .007). Patients reporting multiple adverse experiences described the lowest health-related quality of life, with maximal impairments in psychosocial functioning (p < .005) and only small limitations in physical function.

CONCLUSIONS

Long-term survivors of ARDS describe a good overall health-related quality of life. Major impairments in mental health domains of health-related quality of life are associated with the development of posttraumatic stress disorder and are a possible result of traumatic experiences during ICU therapy.

The effect of stress doses of hydrocortisone during septic shock on posttraumatic stress disorder in survivors

BACKGROUND

Exposure to intense physical and psychological stress during septic shock can result in posttraumatic stress disorder in survivors. Patients with chronic posttraumatic stress disorder often show sustained reductions in serum cortisol concentration. This investigation examines whether increasing serum cortisol levels with hydrocortisone treatment during septic shock reduces the incidence of posttraumatic stress disorder in survivors.

METHODS

Patients (n = 20) were recruited from a prospective, randomized double-blind study on the hemodynamic effects of hydrocortisone during septic shock. Eleven patients had received placebo and nine stress doses of hydrocortisone. Posttraumatic stress disorder was diagnosed 31 months (median) after intensive care unit discharge using SCID-IV (DSM-IV-criteria). Furthermore, the number of categories of traumatic memory from ICU treatment was determined in both groups at that time.

RESULTS

Only one of nine patients from the hydrocortisone group developed posttraumatic stress disorder, compared with seven of 11 patients in the placebo group (p =.02). There was no significant difference with regard to the number of categories of traumatic memory between the hydrocortisone and placebo groups.

CONCLUSIONS

The administration of hydrocortisone during septic shock in a dosage similar to the endogenous maximal production rate was associated with a lower incidence of posttraumatic stress disorder in long-term survivors, which seems to be independent of the number of categories of traumatic memory.

The relationship between cognitive performance and employment and health status in long-term survivors of the acute respiratory distress syndrome: results of an exploratory study

Survivors of acute respiratory distress syndrome (ARDS) are at risk for long-lasting cognitive decline due to hypoxemia, sepsis and/or psychological sequelae associated with aggressive supportive care in the intensive care unit (ICU). We conducted an exploratory study to assess cognitive performance in long-term survivors of ARDS and to investigate how cognitive functioning is related to employment status and health-related quality of life (HRQOL). At median time of 6.0 years after ICU discharge, forty-six ARDS survivors were tested with SKT, a short cognitive performance test for assessing deficits of memory and attention. A measure of HRQOL (SF-36 Health Status Questionnaire) was also administered, and in a brief psychiatric interview, employment status was rated. 23.9% (n=11) of the patients showed cognitive impairments. However, no extreme and severe cognitive deficits were recorded. They primarily revealed low levels of cognitive function in various tasks assessing attention skills. Disability was found in 41.3% (n=19) of the patients. All ARDS survivors with cognitive deficits were disabled, whereas only 22.9% (n=8) of the cognitively not impaired patients gave evidence of disability. The SF-36 values of the ARDS survivors indicated impaired health status on seven out of eight domains when compared to normative population data. Patients with cognitive deficits described the lowest HRQOL with major limitations in the domains role-physical and social functioning when compared to patients without cognitive impairments. In conclusion, long-term ARDS survivors exhibit impaired health status and the presence of cognitive deficits is associated with disability and considerable impairments in HRQOL. More detailed psychiatric research is required to establish the etiology of these cognitive impairments.

Sensitivity and specificity of a screening test to document traumatic experiences and to diagnose post-traumatic stress disorder in ARDS patients after intensive care treatment

OBJECTIVE

Many survivors of critical illness and intensive care unit (ICU) treatment have traumatic memories such as nightmares, panic or pain which can be associated with the development of posttraumatic stress disorder (PTSD). In order to simplify the rapid and early detection of PTSD in such patients, we modified an existing questionnaire for diagnosis of PTSD and validated the instrument in a cohort of ARDS patients after long-term ICU therapy.

DESIGN

Follow-up cohort study.

SETTING

The 20-bed ICU of a university teaching hospital.

PATIENTS

A cohort of 52 long-term survivors of the acute respiratory distress syndrome (ARDS).

INTERVENTIONS AND MEASUREMENTS

The questionnaire was administered to the study cohort at two time points 2 years apart. At the second evaluation, the patients underwent a structured interview with two trained psychiatrists to diagnose PTSD according to Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. The reliability and validity of the questionnaire was then estimated and its specificity, sensitivity and optimal decision threshold determined using receiver operating characteristic (ROC) curve analyses.

RESULTS

The questionnaire showed a high internal consistency (Crohnbach's alpha = 0.93) and a high test-retest reliability (intraclass correlation coefficient alpha = 0.89). There was evidence of construct validity by a linear relationship between scores and the number of traumatic memories from the ICU the patients described (Spearman's rho = 0.48, p < 0.01). Criterion validity was demonstrated by ROC curve analyses resulting in a sensitivity of 77.0% and a specificity of 97.5% for the diagnosis of PTSD.

CONCLUSIONS

The questionnaire was found to be a responsive, valid and reliable instrument to screen survivors of intensive care for PTSD.

Health-related quality of life and post-traumatic stress disorder in patients after cardiac surgery and intensive care treatment

OBJECTIVES

Health-related quality of life and patient satisfaction have become important end points in cardiac surgery. Post-traumatic stress disorder has been described in patients with life-threatening heart disease. In this study, we investigated the occurrence of post-traumatic stress disorder in a sample of patients after cardiac surgery and compared health-related quality of life and patient satisfaction between patients with and without evidence of post-traumatic stress disorder.

METHODS

We studied 80 patients serially admitted to the intensive care unit after cardiac surgery (bypass grafting, n = 51; aortic valve replacement, n = 29). Health-related quality of life was assessed with the use of the SF-36 Health Status Questionnaire. Post-traumatic stress disorder was measured with a previously validated instrument (the Post-Traumatic Stress Syndrome 10-Questions Inventory), and 20 different aspects of life satisfaction were quantified on a scale ranging from 0 to 10. For measurements of health-related quality of life and post-traumatic stress disorder, age- and gender-comparable healthy individuals, as well as patients with cardiovascular diseases, served as control groups.

RESULTS

Patients who had cardiac surgery described high life satisfaction summary scores (156 of a maximum of 200 points) and only small impairments in physical and mental SF-36 summary scores when compared with healthy control groups (median reduction 7.15, P <.05). Patients with evidence of post-traumatic stress disorder (n = 15) reported the lowest SF-36 mental health summary scores when compared with patients without stress disorder (38.3 vs 48.4, P =.004) and rated their life satisfaction lower (121.5 vs 162.0, P =.002).

CONCLUSIONS

Patients who have had cardiac surgery demonstrate a high life satisfaction with an acceptable degree of physical and mental health-related quality of life. Impairments in psychosocial function and life satisfaction were found in a subgroup of patients with evidence of post-traumatic stress disorder.

The effect of stress doses of hydrocortisone during septic shock on posttraumatic stress disorder and health-related quality of life in survivors

OBJECTIVES

The exposure to intense physical and psychological stress during intensive care can result in posttraumatic stress disorder (PTSD) in survivors. Cortisol is a biological stress mediator that can have a protective effect during severe stress. The administration of stress doses of hydrocortisone during treatment in the intensive care unit could theoretically result in a lower incidence of PTSD. We tested this hypothesis in survivors of septic shock.

DESIGN

A retrospective case-controlled analysis.

SETTING

A 20-bed multidisciplinary intensive care unit of a tertiary-care university hospital.

PATIENTS

We identified 27 patients who received standard therapy for septic shock. These patients served as controls and were compared with an equal number of patients who received hydrocortisone in addition to standard treatment. These patients were selected from our database with regard to age (+/-4 yrs), gender, and cause of septic shock to be as similar as possible with control patients.

INTERVENTIONS

Patients from the hydrocortisone group had received stress doses of hydrocortisone (100 mg bolus, followed by 0.18 mg/kg/hr) in addition to standard treatment. Patients from the control group received standard protocol-driven treatment only. PTSD was diagnosed with the Posttraumatic Stress Syndrome-10 inventory, a self-report scale for diagnosis of PTSD. Health-related quality of life was measured using the Medical Outcomes Study Short-Form Survey (Medical Outcomes Trust, Boston, MA), which consists of 36 questions.

MEASUREMENTS AND MAIN RESULTS

Patients who received hydrocortisone during septic shock had a significantly lower incidence of PTSD than patients who received standard treatment only (5 of 27 vs. 16 of 27; p = .01) and had significantly higher scores on the mental health index of the Medical Outcomes Study Short-Form health-related quality-of-life questionnaire (68 vs. 44 points; p = .009).

CONCLUSIONS

Data from this study support the hypothesis that the administration of stress doses of hydrocortisone in doses equivalent to the maximal endocrine secretion rate during septic shock reduces the incidence of PTSD and improves emotional well-being in survivors. This hypothesis should be tested in a prospective randomized trial.

Pulmonary function and health-related quality of life in a sample of long-term survivors of the acute respiratory distress syndrome

OBJECTIVE

We performed a follow-up cohort analysis in order to delineate the correlation between pulmonary function (PF) and health-related quality of life (HRQL) in patients after ARDS.

DESIGN

Follow-up cohort study.

SETTING

A 20-bed ICU of a university teaching hospital.

PATIENTS

A cohort of 50 long-term survivors of ARDS.

MEASUREMENTS AND RESULTS

Measurements of PF (FVC, FEV1, TLC, D(LCO)) and HRQL (SF-36 Health Status Questionnaire) were made 5.5 years (median value) after discharge from the ICU. Impairments in PF (defined as PF results below 80% of the predicted value) were frequent but generally mild. Twenty patients had a single PF impairment (with limitations in FEV1/FVC ratio in 12 patients being the most common), four patients had two (with D(LCO) and FEV1/FVC ratio impairment the most common) and three patients had pathologic results in three PF tests (FEV1/FVC ratio, TLC and capillary pO2 during exercise in one case, FVC, TLC and capillary pO2 during exercise in the second patient and FVC, TLC and D(LCO) in the third). Compared to normal controls, survivors of ARDS showed impairments in all SF-36 health dimensions (p < 0.001). Patients with multiple (> 1) PF impairments described the lowest HRQL with major limitations in all SF-36 categories (p < 0.037) including physical and mental summary scores (36.5 vs 46.9, p = 0.037 and 31.3 vs 51.4, p = 0.003) when compared to patients with no or only one PF impairment.

CONCLUSIONS

Long-term survivors of ARDS have a significant reduction in HRQL and the presence of multiple PF impairments is associated with maximal decrements in HRQL.

A comparison of the adrenocortical response during septic shock and after complete recovery

OBJECTIVE

To compare the adrenocortical response to corticotropin during septic shock and after complete recovery.

DESIGN

Prospective clinical study.

SETTING

Multidisciplinary intensive care unit in a university hospital.

PATIENTS

20 consecutive patients surviving septic shock. All patients met the American College of Chest Physicians/Society of Critical Care Medicine criteria for septic shock. In addition, the presence of high-output circulatory failure with a cardiac index > 41/min per m2 was a criterion for enrollment in the study. Complete recovery from septic shock was defined as discontinuation of any supportive therapies. Severity of illness during septic shock and after recovery was graded using the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system.

INTERVENTIONS

In each patient, two short corticotropin stimulation tests were done during septic shock and after recovery.

MEASUREMENTS AND RESULTS

Basal cortisol levels recorded during septic shock and after recovery did not differ (medians: 18.8 vs 18.9 micrograms/dl). However, the response to corticotropin was significantly attenuated during septic shock when compared with the response after recovery (medians: 7.7 vs 14.7 micrograms/dl; p = 0.02). After recovery, patients' stress response was less, as indicated by a reduction in APACHE II scores (medians: 21 vs 5 points; p < 0.01).

CONCLUSIONS

Adrenocortical response to corticotropin is attenuated in patients with septic shock and high-output circulatory failure compared to the response in the much less stressful condition after recovery. The attenuated adrenocortical responsiveness may be explained by effects of circulating mediators from the systemic inflammatory response.

The Munich Gallbladder Lithotripsy Study. Results of the first 5 years with 711 patients

OBJECTIVE

To evaluate the long-term results of three types of shock wave treatment in patients with radiolucent gallbladder stones.

DESIGN

Cohort study.

SETTING

Single-center trial.

PATIENTS

Of 5824 patients with gallstones, 19% were eligible; 711 patients were treated.

INTERVENTIONS

Patients received extracorporeal shock wave lithotripsy as well as adjuvant therapy with bile acids.

RESULTS

Lithotripsy was done in three ways, using a water-tank lithotriptor (group A), a water-cushion lithotriptor at low energy levels (group B), and a water-cushion lithotriptor at high energy levels (group C). The rate of complete fragment clearance 9 to 12 months after lithotripsy was done differed significantly among the three groups: Among patients with single stones of 20 mm or less in diameter, the rate of fragment clearance for group A was 76%; for group B, it was 60%; and for group C, it was 83% (P = 0.03). Among patients with single stones of 21 to 30 mm, the rate of fragment clearance for group A was 63%; for group B, it was 32%; and for group C, it was 58% (P less than 0.005). Among patients with two or three stones, the rate of fragment clearance for group A was 38%; for group B, it was 16%; and for group C, it was 46% (P = 0.01). Patients with fragments of 3 mm or less 24 hours after lithotripsy was done showed a higher probability of fragment disappearance than did those with larger fragments (P less than 0.001). The clearance rate was higher in patients who were compliant than in those who were noncompliant with bile acid therapy (P less than 0.001). Adverse effects included liver hematoma in 1 patients, biliary pain attacks in 253 patients (36%), mild biliary pancreatitis in 13 patients (2%), and cholestasis in 7 patients (1%). Elective cholecystectomy was done in 16 patients (2%), and endoscopic sphincterotomy was done in 4 patients (1%).

CONCLUSIONS

The rate of complete disappearance of stones after shock wave therapy depends on the size and the number of the initial stones, the diameter of the largest fragment, and the mode of shock wave treatment. Adjuvant therapy with bile acids appears to be important for complete fragment clearance.

Effects of noninvasive positive pressure ventilatory support in non-COPD patients with acute respiratory insufficiency after early extubation

OBJECTIVE

To investigate the effects of noninvasive positive pressure ventilation (NPPV) on pulmonary gas exchange, breathing pattern, intrapulmonary shunt fraction, oxygen consumption, and resting energy expenditure in patients with persistent acute respiratory failure but without chronic obstructive pulmonary disease (COPD) after early extubation.

DESIGN

Prospective study.

SETTING

Multidisciplinary intensive care unit of a university hospital.

PATIENTS

15 patients after prolonged mechanical ventilation (> 72 h) with acute respiratory insufficiency after early extubation.

INTERVENTIONS

Criteria for early extubation were arterial oxygen tension (PaO2) > or = 40 mm Hg (fractional inspired oxygen 0.21), arterial carbon dioxide tension (PaCO2) < or = 55 mm Hg, pH > 7.32, respiratory rate < or = 40 breaths per min, tidal volume (VT) > or = 3 ml/kg, rapid shallow breathing index < or = 190 and negative inspiratory force > or = 20 cmH2O. After extubation, two modes of NPPV were applied [continuous positive airway pressure (CPAP) of 5 cmH2O and pressure support ventilation (PSV) with 15 cmH2O pressure support].

MEASUREMENTS AND MAIN RESULTS

Oxygenation and ventilatory parameters improved during both modes of NPPV (p < 0.05): increase in PaO2 of 11 mm Hg during CPAP and 21 mm Hg during PSV; decrease in intrapulmonary shunt fraction of 7% during CPAP and 12% during PSV; increase in tidal volume of 1 ml/kg during CPAP and 4 ml/kg during PSV; decrease in respiratory rate 6 breaths/min during CPAP and 9 breaths/min during PSV. Oxygen consumption (15% during CPAP, 22% during PSV) and resting energy expenditure (12% during CPAP, 20% during PSV) were reduced (p < 0.05). PaCO2 decreased, whereas minute ventilation and pH increased during PSV (p < 0.05). The median duration of NPPV was 2 days. Two patients had to be reintubated.

CONCLUSIONS

In non-COPD patients with persistent acute respiratory failure after early extubation, NPPV improved pulmonary gas exchange and breathing pattern, decreased intrapulmonary shunt fraction, and reduced the work of breathing.

Extracorporeal shock waves stimulate frog sciatic nerves indirectly via a cavitation-mediated mechanism

Shock waves (SWs) are single pressure pulses with amplitudes up to over 100 MPa, a rise time of only a few nanoseconds, and a short duration of approximately 2 microseconds. Their clinical application for stone destruction causes pain, indicating nerve stimulation by SWs. To examine this phenomenon, sciatic nerves of frogs were exposed to SWs in an organ bath. The SWs were generated with an experimental Dornier lithotripter model XL1 at an operating voltage of 15 kV. The nerves were mounted in a chamber which allowed electrical nerve stimulation and the registration of electrically and SW-induced compound action potentials (SWCAPs). The chamber was filled with frog Ringer's solution. In a standardized protocol. The first experiment established that 95.0 +/- 4.7% of administered SWs induced action potentials which were lower in amplitude (1.45 +/- 1.14 versus 1.95 +/- 0.95 mV, p = 0.004) but similar in shape to electrically induced compound action potentials. In a second experiment, it was shown that the site of origin of the SWCAPs could be correctly determined by simultaneous recording of action potentials at both ends of the nerve. The mechanism of shock wave stimulation was examined by experiments 3 and 4. In experiment 3, in contrast to the previous experiments, SW exposure of the nerves was performed 6 cm outside the shock wave focus. This resulted in a mean probability of inducing a SWCAP of only 4%. After gas bubble administration, this probability increased to 86% for the first SW released immediately after bubble application and declined to 56% for the second, 21% for the third, to 0 for the 10th SW after fluid injection. This indicates that cavitation, the interaction between shock waves and gas bubbles in fluid or tissues, was involved in SWCAP generation. In experiment 4, nerves were again exposed in the focus, however, the Ringer's solution surrounding the nerve was replaced by polyvinyl alcohol (PVA). PVA is a solution with low cavitation activity.In PVA, the excitability was markedly diminished to 11.0 +/- 5.1% compared with 96.0 +/- 4.4% in control nerves exposed in Ringer's solution. In conclusion, bioeffects of SWs on nervous tissue appear to result from cavitation. It is suggested that cavitation is also the underlying mechanism of SW-related pain during extracorporeal SW lithotripsy in clinical medicine.

Effects of exercise stress on the endocannabinoid system in humans under field conditions

The effects of physical exercise stress on the endocannabinoid system in humans are almost unexplored. In this prospective study, we investigated in a crossover design and under field conditions at different altitudes the effects of physical exercise on the endocannabinoid system (ECS) in 12 trained healthy volunteers. For determination of alterations on the ECS three different protocols were analyzed: Protocol A (physical exercise at lower altitude) involved strenuous hiking below 2,100 m, whereas Protocol B (physical exercise by active ascent to high altitude) involved hiking up to 3,196 m, an accommodation at the cottage and a descent the next day. Protocol C (passive ascent) included a helicopter ascent to 3,196 m, an overnight stay at this altitude and a flight back to the base camp the following day. The cumulative hiked altitude in Protocol A and B was comparable (~1,650 m). The blood EC concentrations of anandamide increased significantly in Protocol A/B from baseline (T0) 0.12 ± 0.01/0.16 ± 0.02 (mean ± SEM) to 0.27 ± 0.02/0.42 ± 0.02 after exercise (T1) (p < 0.05). Anandamide levels in Protocol C remained stable at 0.20 ± 0.02. We conclude that the ECS is activated upon strenuous exercise whereas the combination with hypoxic stress further increases its activity. The reduced partial pressure of oxygen at high altitude alone did not affect this system. In summary, physical exercise activates the endocannabinoid system, whereas the combination with high altitude enhances this activation. This discloses new perspectives to adaptation mechanisms to physical exercise.

Application of a fibrinogen-thrombin-collagen-based hemostyptic agent in experimental injuries of liver and spleen

FTCH is a recently developed material which consists of a collagen fleece containing fibrinogen, thrombin, and aprotinin integrated into its surface. FTCH is highly effective in sealing of tissues and in establishing hemostasis. We evaluated FTCH in experimentally produced liver (n = 6) and splenic (n = 12) injuries in 18 adult mongrel dogs. The stability of the parenchymal seal of the splenic injuries was tested by splenic tissue pressure elevation after temporary ligation of the splenic vein. No breakthrough bleeding occurred up to a parenchymal pressure of 16.3 +/- 5 mm Hg. Complete hemostasis was easily achieved in all animals before closure. When the dogs were re-explored postoperatively at intervals of either 14 or 30 days, there was no gross evidence of recurrent bleeding. Histologic examinations demonstrated a partially regenerated capsule covering an unspecific fibrovascular granulation tissue and progressive resorption of FTCH without significant inflammatory response. We conclude the following: FTCH provides adequate hemostatic control of experimental liver and splenic injuries. FTCH has excellent tissue compatibility and can be applied easily and safely to hemorrhaging parenchymal wounds. It will not replace adequate surgical techniques, but could be useful as a quickly available and easily applicable hemostatic means in diffuse or acute bleeding of liver and spleen.

Treatment of depression with methylphenidate in patients difficult to wean from mechanical ventilation in the intensive care unit

BACKGROUND

Mechanical ventilation is often required to support patients in the intensive care unit (ICU) with life-threatening cardiovascular, respiratory, or neuromuscular disorders. Occasionally, difficulties related to weaning patients from this support occur owing to depression. The traditional and newer-generation antidepressant drugs have a relatively long latency of response that interferes with rehabilitation attempts in the ICU. Psychostimulants such as methylphenidate show a rapid onset of antidepressant activity and a benign side effect profile.

METHOD

As consulting psychiatrists in the consultation-liaison service of a university hospital, we treated 7 patients with complex ICU courses presenting prolonged mechanical ventilation and psychomotor retardation associated with markedly depressed mood (DSM-IV criteria) by giving them methylphenidate. Methylphenidate was started on the first day at a dose of 2.5 mg p.o. in the morning and was increased by 2.5 mg each day with twice-a-day dosing in the morning and at noon until the patient responded or showed side effects. A maximum dose of 15 mg/day was not exceeded. Outcome evaluation was performed using the Clinical Global Impressions scale.

RESULTS

Five (71 %) of 7 patients showed marked or moderate improvement in mood and activity within 3 to 4 days, and discontinuation of ventilator support was achieved within 8 to 14 days. Side effects with these 5 patients were not encountered. Of the remaining 2 patients (29%), 1 developed psychomotor agitation and anxiety within 4 days. Another patient showed only minimal improvement with regard to activity.

CONCLUSION

Methylphenidate might be a rapidly effective and safe treatment for depression in difficult-to-wean patients hospitalized for life-threatening medical illness in the ICU. Implications for future research for this population of patients warrant formal randomized, prospective, clinical case-control evaluation.

A beta-adrenergic antagonist reduces traumatic memories and PTSD symptoms in female but not in male patients after cardiac surgery

BACKGROUND

Epinephrine enhances emotional memory whereas beta-adrenoceptor antagonists (beta-blockers, BBs) impair it. However, the effects of BB administration on memory are sex dependent. Therefore, we predicted differential effects of epinephrine and the BB metoprolol given to male and female patients after cardiac surgery (CS) on traumatic memories and post-traumatic stress disorder (PTSD) symptoms.

METHOD

We performed a prospective observational study and determined the number of standardized traumatic memories (NTRM) and PTSD symptom intensity in cardiac surgical patients at 1 day before surgery, and at 1 week and 6 months after the procedure. PTSD symptoms and NTRM were quantified using validated questionnaires. Metoprolol could be administered any time post-operatively.

RESULTS

Baseline NTRM was not significantly different between male (n=95) and female patients (n=33). One week after CS, the NTRM in male patients was significantly higher. Metoprolol had no significant effect in either sex. At 6 months, females with metoprolol (n=18) showed a significantly lower NTRM and significantly lower PTSD symptom scores than females without BBs (n=15, p=0.02). By contrast, the totally administered dosage of epinephrine correlated with NTRM in males (r=0.33, p<0.01) but not in females (r=0.21, p=0.29).

CONCLUSIONS

beta-Adrenergic stimulation with epinephrine enhances memory for adverse experiences in males but not in females whereas beta-blockade selectively reduces memory for post-operative adverse events and PTSD symptoms in females.

Enhanced anandamide plasma levels in patients with complex regional pain syndrome following traumatic injury: a preliminary report

The complex regional pain syndrome (CRPS) is a disabling neuropathic pain condition that may develop following injuries of the extremities. The pathogenesis of this syndrome is not clear; however, it includes complex interactions between the nervous and the immune system resulting in chronic inflammation, pain and trophic changes. This interaction may be mediated by chronic stress which is thought to activate the endogenous cannabinoid (endocannabinoid) system (ECS). We conducted an open, prospective, comparative clinical study to determine plasma level of the endocannabinoid anandamide by high-performance liquid chromatography and a tandem mass spectrometry system in 10 patients with CRPS type I versus 10 age- and sex-matched healthy controls. As compared to healthy controls, CRPS patients showed significantly higher plasma concentrations of anandamide. These results indicate that the peripheral ECS is activated in CRPS. Further studies are warranted to evaluate the role of the ECS in the limitation of inflammation and pain.

520-d Isolation and confinement simulating a flight to Mars reveals heightened immune responses and alterations of leukocyte phenotype

During interplanetary exploration, chronic stress caused by long term isolation and confinement in the spacecraft is one of the major concerns of physical and psychological health of space travelers. And for human on Earth, more and more people live in an isolated condition, which has become a common social problem in modern western society. Collective evidences have indicated prolonged chronic stress could bring big influence to human immune function, which may lead to a variety of health problems. However, to what extent long-term isolation can affect the immune system still remains largely unknow. A simulated 520-d Mars mission provided an extraordinary chance to study the effect of prolonged isolation. Six healthy males participated in this mission and their active neuroendocrine and immune conditions were studied with saliva and blood samples from all participants on chosen time points during the isolation period. As a typical neuroendocrine parameter, stress hormone cortisol was measured in the morning saliva samples. Immune phenotype changes were monitored through peripheral leukocyte phenotype analysis. Using an ex vivo viral infection simulation assay we assessed the immune response changes characterized by the ability to produce representative endogenous pro-inflammatory cytokines. The results of this study revealed elevated cortisol levels, increased lymphocyte amount and heightened immune responses, suggesting that prolonged isolation acting as chronic stressors are able to trigger leukocyte phenotype changes and poorly controlled immune responses.

Effect of anaesthesia and cardiopulmonary bypass on blood endocannabinoid concentrations during cardiac surgery

BACKGROUND

The endocannabinoid system (ECS) is an endogenous signalling system which includes the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) and specific G-protein-coupled endocannabinoid receptors (CB1 and CB2). Recent studies have described important roles of the peripheral ECS in human atherosclerosis, cardiometabolic disorders, heart failure, and systemic inflammation. We sought to study changes in plasma endocannabinoid concentrations during cardiac surgery (CS) under general anaesthesia with isoflurane/sufentanil, and during cardiopulmonary bypass (CPB).

METHODS

We studied 30 patients undergoing CS with CPB. All patients received midazolam and sufentanil for induction and isoflurane and sufentanil for maintenance of general anaesthesia. Blood samples were drawn before and after induction of general anaesthesia, after the beginning of surgery, during and after weaning from CPB, and after admission to intensive care unit (ICU) after surgery. Endocannabinoid measurements were performed by HPLC-tandem mass spectrometry.

RESULTS

Induction of general anaesthesia led to a significant decline in plasma AEA concentrations [from mean (sd) 0.39 (0.03) to 0.27 (0.03) ng ml(-1), P<0.01]. CPB induced a pronounced increase in 2-AG concentrations [from 112.5 (163.5) to 321.0 (120.4) ng ml(-1), P<0.01], whereas AEA concentrations remained persistently low until admission to the ICU. 2-AG concentrations returned to preoperative values after surgery.

CONCLUSIONS

General anaesthesia with isoflurane significantly reduces plasma AEA concentrations. This could be a consequence of stress reduction after loss of consciousness. The significant increase in 2-AG after initiation of CPB may be part of an inflammatory response. These findings suggest that anaesthesia and surgery have differential effects on the ECS which could have substantial clinical consequences.

Patient controlled analgesia for shock wave lithotripsy: the effect of self-administered alfentanil on pain intensity and drug requirement

PURPOSE

Second generation lithotriptors offer immersion-free treatment and a decrease in shock wave induced pain. Pain sensations caused by advanced lithotriptors vary widely and have a significant impact on clinical management. We tested patient controlled analgesia during extracorporeal shock wave lithotripsy (ESWL) and quantified analgesic requirements by means of patient controlled analgesia during ESWL of renal stones.

MATERIALS AND METHODS

Patients with renal stone disease undergoing ESWL were randomized prospectively to receive an alfentanil infusion titrated by 4 different anesthesiologists not otherwise involved in the study (22 controls) or to self-administer alfentanil via a patient controlled infusion pump (22 patients). As a measure of individual pain sensitivity the detection, pain and tolerance thresholds of electrocutaneous sensitivity were determined in all patients.

RESULTS

Alfentanil was used more often in the patient controlled analgesia group than in the control patients (12 versus 8 required the narcotic, respectively, p = 0.226). Patients using patient controlled analgesia needed less drug (0.5 versus 2.15 mg., p = 0.005, median values), tolerated higher discharge voltages and pain intensities, needed significantly fewer shock waves to complete stone fragmentation (1,612 versus 2,105, p = 0.014) and had shorter treatment times (36.9 versus 46.2 minutes, p = 0.069). There was a significant correlation between the duration of shock wave exposure tolerated without analgesia, and pain (p = 0.0009) and tolerance (p = 0.0020) thresholds but not with regard to detection thresholds (p = 0.1400). Male patients showed significantly higher tolerance thresholds to electrocutaneous stimulation (10.2 versus 6.9 mA., p = 0.0238), which corresponded to longer analgesia-free treatment times in male versus female patients (31.7 versus 19.4 minutes, p = 0.0510).

CONCLUSIONS

Patient controlled analgesia increases pain tolerance, decreases narcotic requirements, simplifies ESWL as an outpatient procedure and can be used to quantify analgesic requirements during lithotripsy. Pain and tolerance thresholds of electrocutaneous sensitivity are sensitive markers of pain tolerance during lithotripsy, which may be more pronounced in male patients.

[Health-related quality of life. Long-term survival in patients with ARDS following extracorporeal membrane oxygenation (ECMO)]

Treatment of severe acute respiratory distress syndrome (ARDS) with extracorporeal membrane oxygenation (ECMO) can be lifesaving but requires maximal use of intensive care resources over prolonged periods of time, resulting in high costs. Little is known about the health-related quality of life (HRQL) in long-term survivors. This case-controlled retrospective study was designed to assess the health-related quality of life in long-term survivors of ARDS and ECMO-therapy.

METHODS

14 long-term survivors of ARDS (APACHE II score = 24, Lung Injury Score = 3.25, median values) treated using ECMO between 1992 and 1995 (median time interval between data collection and discharge from the ICU 16 months) and 14 ARDS-patients conventionally treated during the same period (group I) were identified and completed the SF-36 Health Status Questionnaire (Medical Outcome Trust, Boston, USA). 14 healthy subjects (group II) were drawn at random from a large data base generated to provide normal values for the SF-36 in a German population. All three groups were comparable with respect to sex and age.

RESULTS

Long-term survivors of ECMO-therapy reported significant reductions in physical functioning when compared with patients treated by mechanical ventilation alone (group I, -12.5%, p < 0.05) and with healthy controls (group II, -50%, p < 0.05) and showed a higher incidence of chronic physical pain (+5% and +24%, respectively, p < 0.05). There were no differences with regard to the mental health dimensions of the SF-36 (e.g. vitality, mental health index or social functioning) between ECMO-patients and all controls. Nine patients (64.3%) from the ECMO group versus all patients treated conventionally (group I) had full-time employment (p = 0.46, Chi2 test).

CONCLUSIONS

The majority of long-term survivors of ECMO-treatment show good physical and social functioning, including a high rate of employment. The more aggressive approach of ECMO-therapy and a possibly more severe underlying disease process may explain impairments in health-related quality of life outcomes after ECMO-treatment. Despite these limitations, long-term survivors of ECMO-therapy are able to reach a highly satisfactory health-related quality of life.

The effectiveness of a fibrinogen-thrombin-collagen-based hemostatic agent in an experimental arterial bleeding model

The hemostyptic agent used in this study is a recently developed material that consists of a collagen fleece containing fibrinogen, thrombin, and aprotinin integrated into its surface (FTCH) with excellent topical hemostyptic properties. The potential use of this substance for cardiovascular surgery was evaluated in a canine arterial bleeding model, which allowed comparison of the new agent with previously used pure collagen (CHF) as well as study of the hemostyptic under elevated blood pressure conditions. The results revealed that FTCH induced reliable hemostasis in 10-mm injuries of the canine hypogastric artery up to a systolic blood pressure of 260 mmHg, whereas bleeding control by CHF alone was impossible. To assess the long-term reliability of FTCH, the dogs were re-explored at intervals of 14 and 31 days after operation. At relaparotomy, the arteries were patent and there was no evidence of recurrent bleeding, thrombosis formation, or aneurysmatic changes. Histologic examinations showed well-healed vascular lesions covered by cell-depleted collagen tissue and a partially resorped hemostyptic. FTCH will not replace adequate surgical techniques but could be useful as a quickly available and easily applicable hemostatic means in otherwise uncontrollable diffuse or acute bleeding in cardiovascular surgery.

Parabolic flight primes cytotoxic capabilities of polymorphonuclear leucocytes in humans

BACKGROUND

Previously performed in vitro studies suggested that gravitational stress may alter functions of immune cells. This study investigated the in vivo effects of parabolic flight manoeuvres as a short-term model of micro- and hypergravity on the cytotoxic and microbicidal polymorphonuclear leucocyte (PMN) functions as the key element of innate immunity.

MATERIAL AND METHODS

Twenty-one healthy male volunteers underwent 30 subsequent parabolic flight manoeuvres. Each manoeuvre produced 22-s periods of nearly weightlessness close to <<0g>>, with each parabola starting with a pull-up and ending with a pull-out (hypergravity) at 1.8 g for about 20 s each. Blood samples were drawn 24 h prior to take off (T0), after 25-30 parabolas (T1), and 24 h (T2) and 48 h (T3) after flight for determination of (i) leucocyte number and subpopulations, (ii) PMNs' capabilities to produce hydrogen peroxide (H(2)O(2)) and to adhere and phagocytose particles and (iii) plasma cytokines known to prime PMN functions [interleukin-8 (IL-8), tumour necrosis factor-alpha (TNF-alpha), granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF)].

RESULTS

Parabolic flight induced an increase in leucocyte number with a significant elevation of the PMN fraction. The spontaneous H(2)O(2) production by PMNs did not change; however, the capability of PMNs to produce H(2)O(2) in response to soluble stimuli [N-formyl-methionyl-leucyl-phenylalanine (fMLP), fMLP and TNF-alpha, calcium ionophore (A23187), phorbol myristate acetate (PMA)] was increased. Adhesive and phagocytic properties of PMNs were not altered. Regarding priming cytokines, IL-8 and G-CSF were significantly elevated.

CONCLUSIONS

Our data indicate that parabolic flight induces priming of the cytotoxic capabilities of PMNs without affecting microbicidal functions.