Endocrine profiles for outcome prediction from the intensive care unit

Association of thyroid hormones and thyroid-stimulating hormone with mortality in adults admitted to the intensive care unit: A systematic review and meta-analysis

BACKGROUND

Thyroid hormones (THs) and thyroid-stimulating hormone (TSH) seem to show high potential in predicting the clinical death outcome of patients admitted to the intensive care unit (ICU). However, diverse studies on this topic are conflicting.

METHODS

A search was conducted by two investigators involved in this research in the PubMed, Embase, and Cochrane databases (all last launched on July 12, 2021). The quality of the included studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale (NOS). Subgroup analyses were performed to determine the sources of heterogeneity. Sensitivity and publication bias analyses were also assessed.

RESULTS

A total of 27 studies (4970 participants) were included based on the eligibility criteria. Compared with survivors, nonsurvivors were found to have lower levels of THs (T3, T4, fT3, and fT4), whereas no significant difference was found in TSH levels (13 studies for T3: standardized mean differences [SMD], -0.78; 95% CI, -1.36 to -0.20; I2 = 96%; p = 0.008; 11 studies for T4: SMD = -0.79; 95% CI, -1.31 to -0.28; I2 =95%; p = 0.0002; 14 studies for fT3: SMD = -0.76; 95% CI, -1.21 to -0.32; I2 = 95%; p = 0.0008; 17 studies for fT4: SMD = -0.60; 95% CI, -0.99 to -0.22; I2 = 95%; p = 0.002; 20 studies for TSH: SMD = 0.00; 93% CI, -0.29 to 0.29; I2 = 93%; p = 0.98).

CONCLUSION

Nonsurvivors were associated with lower levels of THs (T3, T4, fT3, and fT4) than survivors. THs show great application potential in predicting ICU patients' death outcomes and improving already widely used prognostic scores in the ICU (ie, Acute Physiological and Chronic Health Evaluation [APACHE] II and Therapeutic Intervention Scoring System).

Cortisol and adrenocorticotropic hormone concentrations in horses with systemic inflammatory response syndrome

Background

Plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations increase with illness‐associated stress. Dynamics of plasma ACTH and serum cortisol concentrations in adult horses with systemic illness are undocumented.

Hypothesis/Objective

To determine whether ACTH and cortisol concentrations and the ACTH/cortisol ratio vary with survival, the presence of systemic inflammatory response syndrome (SIRS), or ischemic gastrointestinal lesions at admission, or throughout hospitalization.

Animals

One hundred fifty‐one adult horses.

Methods

Prospective study measuring serum cortisol and plasma ACTH at admission and on days 2, 4, and 6 of hospitalization. Horses were grouped by outcome (survival, SIRS status, number of SIRS criteria [SIRS score], SIRS severity group, and the presence of an ischemic lesion). Differences between groups and over time for ACTH, cortisol, and ACTH/cortisol ratio were investigated with a mixed effect model. Receiving operator characteristic curves and odds ratios were calculated for survival and ischemia.

Results

In all groups, ACTH, cortisol, and ACTH/cortisol ratio significantly decreased over time (P < .0001). ACTH, cortisol, and ACTH/cortisol ratio were higher at admission in nonsurvivors, and ACTH and cortisol were higher in horses with ischemic lesions (P < .01). Horses with ACTH above reference interval at admission were 6.10 (2.73‐13.68 [95% confidence interval]) times less likely to survive (P < .0001). No significant difference in ACTH, cortisol, and ACTH/cortisol ratio between horses with different SIRS status, scores, or groups were detected, although nonsurvivors had a higher SIRS score (P < .0001).

Conclusions and Clinical Importance

Pituitary and adrenal responses are altered in nonsurviving horses and those with an ischemic gastrointestinal lesion.

Investigation of serum cortisol concentration as a potential prognostic marker in hospitalized dogs: a prospective observational study in a primary care animal hospital

BACKGROUND

Dogs with various medical diseases are usually treated at hospitals; however, the prognostic markers in dogs remain unknown. The aim of this study was to investigate the ability of serum cortisol concentration (SCC) to predict the prognosis of dogs with medical diseases. At 0 and 24 h after hospitalization, the neutrophil count, lymphocyte count, blood glucose concentration, and SCC were measured. Survival for 30 days from the time of hospitalization was investigated, and the dogs were divided into a survivor group and a non-survivor group.

RESULTS

The neutrophil count at 24 h, SCC at 24 h, increase in SCC from 0 to 24 h (Inc-SCC), and the rate of increase in SCC from 0 to 24 h (R-Inc-SCC) were significantly higher in the non-survivor group than in the survivor group. The area under the receiver operating characteristic (ROC) curve values for the neutrophil count at 24 h, SCC at 24 h, Inc-SCC, and R-Inc-SCC were 0.695, 0.72, 0.63, and 0.66, respectively. Using the highest area under the ROC curve value, the sensitivity and specificity of SCC at a cutoff level of 6.6 μg/dL for predicting mortality were 89.5 and 61.9%, respectively. Moreover, the Kaplan-Meier curves confirmed the significant prognostic influence of SCC at 24 h.

CONCLUSIONS

SCC as a marker of stress is a useful biomarker for predicting the prognosis of dogs with medical diseases requiring hospital treatment.

The protective effect of different airway humidification liquids to lung after tracheotomy in traumatic brain injury: The role of pulmonary surfactant protein-A (SP-A)

The purpose of this study was to establish a rat model of a brain injury with tracheotomy and compared the wetting effects of different airway humidification liquids, afterward, the best airway humidification liquid was selected for the clinical trial, thus providing a theoretical basis for selecting a proper airway humidification liquid in a clinical setting. Rats were divided into a sham group, group A (0.9% NaCl), group B (0.45% NaCl), group C (0.9% NaCl+ambroxol) and group D (0.9% NaCl+Pulmicort). An established rat model of traumatic brain injury with tracheotomy was used. Brain tissue samples were taken to determine water content, while lung tissue samples were taken to determine wet/dry weight ratio (W/D), histological changes and expression levels of SP-A mRNA and SP-A protein. 30 patients with brain injury and tracheotomy were selected and divided into two groups based on the airway humidification liquid instilled in the trachea tube, 0.45% NaCl and 0.9% NaCl+ambroxol. Blood was then extracted from the patients to measure the levels of SP-A, interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor-α (TNF-α). The difference between group C and other groups in lung W/D and expression levels of SP-A mRNA and SP-A protein was significant (P<0.05). In comparison, the histological changes showed that the lung tissue damage was smallest in group C compared to the three other groups. Aspect of patients, 0.45% NaCl group and 0.9% NaCl+ambroxol group were significantly different in the levels of SP-A, IL-6, IL-8 and TNF-α (P<0.01). In the present study, 0.9% NaCl+ambroxol promote the synthesis and secretion of pulmonary surfactant, and has anti-inflammatory and antioxidant effects, which inhibit the release of inflammatory factors and cytokines, making it an ideal airway humidification liquid.

The utility of the corticotropin test to diagnose adrenal insufficiency in critical illness: an update

OBJECTIVE

One of the most common dynamic testing procedures for assessment of adrenocortical function is the standard corticotropin or the cosyntropin test. The aim of this review was to examine the evidence base underlying the corticotropin test in the management of the critically ill patient.

DATA SYNTHESIS

The principle behind the corticotropin test is the demonstration of an inappropriately low cortisol production in response to exogenous ACTH, a situation analogous to physiological stress. The corticotropin test was originally described in nonstressed subjects, and its applicability and interpretation in the setting of critical illness continues to generate controversy. Attempting to determine the prevalence of an abnormal corticotropin test in critical illness is complicated by the use of different end-points and different populations. Moreover, the test result is also influenced by the assay used for measurement of plasma cortisol. Trials assessing the relationship between corticotropin response and severity of stress and organ dysfunction have produced divergent results, which may reflect differences in the methodology and the association being measured. Moreover, controversy exists with respect to the methodology and the interpretation with respect to the following variables: dose of corticotropin, end-points for assessment of total or free cortisol, effect of plasma cortisol variability, adrenal blood flow and its equivalence with other tests of adrenocortical function.

CONCLUSIONS

The corticotropin test is used widely in the evaluation of adrenocortical function in the endocrine clinics. Its role in the critically ill patient is less well established. Several confounding variables exist and to have a 'one-size-fits-all' approach with a single end-point in the face of several methodological and pathophysiological confounders may be flawed and may result in the institution of inappropriate therapy. The current evidence does not support the use of the corticotrophin test in critical illness to assess adrenocortical function and guiding steroid therapy in critical illness.

Increased Total Serum Random Cortisol Levels Predict Mortality in Critically Ill Trauma Patients

Dysfunction in the hypothalamopituitary adrenal axis is thought to exist; however, there continues to be controversy about what level of serum cortisol corresponds to adrenal insufficiency. Few studies have focused on the significance of serum random cortisol in the critically ill trauma patient. Trauma patients with total serum random cortisol levels drawn in the intensive care unit within the first seven days of hospitalization were retrospectively reviewed. The primary outcome measured was in-hospital mortality. Two hundred forty-two patients were analyzed. Non-survivors had significantly higher mean cortisol levels than survivors (28.7 ± 15.80 mg/dL vs 22.9 ± 12.35 mg/dL, P = 0.01). Patients with cortisol 30 mg/dL or greater were more likely to die with odds ratio of 2.7 (95% confidence interval [CI], 1.5 to 5). The odds ratio increased to 4.0 and 3.8 (95% CI, 1.4 to 11.4 and 1.3 to 10.9) when cortisol was drawn on hospital Day 2 and Days 3 through 7, respectively. Among nonsurvivors, patients with an injury severity score less than 25 had significantly higher cortisol levels than patients with an Injury Severity Score 25 or higher (35.3 ± 19.21 mg/dL vs 25.7 ± 13.21 mg/dL, P = 0.009). Patients with massive transfusion, traumatic brain injury, spinal cord injury, or solid organ injury did not have significantly different cortisol levels. The covariate-adjusted area under the receiver operating characteristic curve indicated that cortisol level has a 77 per cent accuracy in differentiating survivors from nonsurvivors. Higher cortisol levels were predictive of mortality in critically ill trauma patients. Whether serum cortisol level is a marker that can be modified remains an area of interest for future study.

Relative adrenal insufficiency in critically ill patient after rapid sequence intubation: KETASED ancillary study

PURPOSE

Relative adrenal insufficiency (RAI) has been reported as a predictor of mortality in septic patient; however, its effects on mortality and outcomes for critically ill patients remain debatable. The objective of this study was to assess the effect of RAI on prognostic outcomes in patients after out-of-hospital rapid sequence intubation (RSI) and factors associated with the onset of RAI.

PATIENTS AND METHODS

A prespecified ancillary study of KETASED, a randomized prospective multicenter trial, was conducted. Three hundred ten patients who underwent RSI in an out-of-hospital setting had baseline cortisol and adrenocorticotropic hormone response test measurements within 24 hours of intensive care unit admission and were included.

RESULTS

The mean (SD) age was 55 (19) years, with a mean (SD) Sequential Organ Failure Assessment score of 9 (4). Two hundred forty-seven (69%) patients presented with RAI. Baseline characteristics were similar between patients with and without RAI, except for the use of etomidate as a sedative agent (63% of patients with RAI vs 21%, P<.001), and history of chronic kidney disease. There was no difference in terms of 28-day mortality between the 2 groups (21% vs 19%, P=.65) and in terms of other 28-day prognosis end points.

CONCLUSION

In critically ill patients who require RSI, RAI is common and is not associated with worsened outcomes in our cohort.

Traumatic brain injury in rats induces lung injury and systemic immune suppression

Traumatic brain injury (TBI) is frequently complicated by acute lung injury, which is predictive for poor outcome. However, it is unclear whether lung injury develops independently or as a result of mechanical ventilation after TBI. Further, TBI is strongly associated with the development of pneumonia, suggesting a specific vulnerability for the development of nosocomial infections in the lung after TBI. In this study, we evaluated whether indeed pulmonary injury and immune suppression develop spontaneously in an animal model of mild TBI (mTBI). TBI was induced in male PVG rats by closed-head trauma using a weight-drop device. Subsequently, we evaluated the effects of this on the lungs as well as on the excitability of the systemic immune system. Finally, we performed an experiment in which TBI was followed by induction of pneumonitis and evaluated whether TBI affects the severity of subsequent pneumonitis induced by intratracheal instillation of heat-killed Staphylococcus aureus. mTBI resulted in significant lung injury, as evidenced by pulmonary edema, protein leakage to the alveolar compartment, and increased concentrations of interleukin-1 and -6 in broncho alveolar lavage fluid (all p<0.05 vs. sham-treated animals). Further, after TBI, the release of tumor necrosis factor alpha was decreased when whole blood was stimulated ex vivo (p<0.05 TBI vs. sham), indicating systemic immune suppression. When TBI was followed by pneumonitis, the severity of subsequent pneumonitis was not different in rats previously subjected to TBI or sham treatment (p>0.05), suggesting that systemic immune suppression is not translated toward the pulmonary compartment in this specific model. We here show that during mild experimental TBI, acute pulmonary injury, as well as a decrease in the excitability of the systemic immune system, can be observed.

Nonthyroidal illness syndrome in enterocutaneous fistulas

BACKGROUND

The aim of this study was to investigate the incidence, etiology, clinical outcomes, and prognosis of nonthyroidal illness syndrome (NTIS) in patients with enterocutaneous fistulas.

METHODS

We prospectively collected 226 patients with enterocutaneous fistulas. Demographics, Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment scores, C-reactive protein, body mass index, albumin, and thyroidal hormones were evaluated for each patient.

RESULTS

The incidence of NTIS was 57.5% in patients with enterocutaneous fistulas. Age and the APACHE II and Sequential Organ Failure Assessment scores were significantly higher, whereas albumin was lower in the NTIS group compared with those in the euthyroid group. A decreased sum activity of deiodinases and a reduced ratio of total thyroxin/free thyroxin and total triiodothyronine/free triiodothyronine were observed in the NTIS group. Patients with NTIS suffered longer durations in the intensive care unit and higher possibilities of mechanical ventilation. The cumulative survival rate was significantly lower in the NTIS group.

CONCLUSIONS

NTIS was common, and patients with NTIS displayed worse clinical outcome and prognosis. A hypodeiodination condition and a potential thyroid hormone-binding dysfunction may play a role in the etiology of NTIS. A low serum albumin concentration and a high APACHE II score were risk factors of NTIS in enterocutaneous fistulas.

Adrenal insufficiency in cardiothoracic patients: an evaluation of the corticotrophin stimulation test and other diagnostic methods

PURPOSE

The purposes of the study were to determine the incidence of adrenal insufficiency (AI) using several published techniques, compare the response rates using a low-dose (LD) corticotropin (ACTH) stimulation test vs a standard dose (SD), and identify the technique that is most closely related to vasopressor use.

MATERIALS AND METHODS

Consecutive adult patients who were undergoing open heart surgery for CAD or valvular disease were prospectively enrolled. Exclusion criteria included history of steroid use, operative steroid, or etomidate administration. Postoperatively, each patient underwent ACTH stimulation with 1 μg (LD) and 249 μg (SD), 60 minutes apart. Agreement among the tests was evaluated, and vasopressor use was compared between groups.

RESULTS

There were 40 patients evaluated. The incidence of AI based on operative change, postoperative values, and LD-ACTH and SD-ACTH tests was 53%, 38%, 60%, and 38%, respectively. Agreement between the LD- and SD-ACTH tests was 73% (κ = 0.476, P = .001). There was a significant difference in the need for (93% vs 52%, P = .013) and duration (18.9 [0-180.6] vs 0.6 [0-73.2] hours, P = .003) of vasopressor therapy in patients with and without AI but only using the SD-ACTH definition.

CONCLUSION

The incidence of AI will vary greatly based on technique used for diagnosis. The SD-ACTH stimulation test should be used to determine AI in open heart patients postoperatively because of the close association with vasopressor usage.

Adrenocortical (dys)function in septic shock - a sick euadrenal state

A central feature of the endocrine pathophysiology of septic shock is thought to be the existence of adrenal dysfunction. Based on changes in glucocorticoid secretion and responsiveness, protein binding, and activity. These changes have been described by the terms "Relative Adrenal Insufficiency" (RAI), or "Critical Illness Related Corticosteroid Insufficiency" (CIRCI), and form part of the rationale for trials of glucocorticoid treatment in septic shock. Diagnostic criteria for these conditions have been based on plasma cortisol profiles and have proven notoriously difficult to establish. The uncertainty in this area arises from the inability of current tests to clearly identify who is truly glucocorticoid "deficient" at a cellular level, and hence who requires supplemental glucocorticoid administration. Emerging data suggest that there may be abnormalities in the tissue activity of glucocorticoids in patients with severe sepsis and plasma profiles may not be reliable indicators of tissue glucocorticoid activity, We put forward an alternative point of view, that is the spectrum of adrenocortical dysfunction in sepsis - plasma and tissue, can be grouped under the umbrella of a "sick euadrenal syndrome" rather than an adrenocortical insufficiency.

Drug-induced endocrine disorders in the intensive care unit

The neuroendocrine response to critical illness is key to the maintenance of homeostasis. Many of the drugs administered routinely in the intensive care unit significantly impact the neuroendocrine system. These agents can disrupt the hypothalamic-pituitary-adrenal axis, cause thyroid abnormalities, and result in dysglycemia. Herein, we review major drug-induced endocrine disorders and highlight some of the controversies that remain in this area. We also discuss some of the more rare drug-induced syndromes that have been described in the intensive care unit. Drugs that may result in an intensive care unit admission secondary to an endocrine-related adverse event are also included. Unfortunately, very few studies have systematically addressed drug-induced endocrine disorders in the critically ill. Timely identification and appropriate management of drug-induced endocrine adverse events may potentially improve outcomes in the critically ill. However, more research is needed to fully understand the impact of medications on endocrine function in the intensive care unit.

Relative adrenal insufficiency in the intensive care population; background and critical appraisal of the evidence

Dysfunction of the hypothalamo-pituitary adrenal axis has become a central feature in descriptions of the pathophysiology of sepsis. However; despite hundreds of published articles including literature reviews and consensus statements, controversy still exists regarding the fundamental nature of the disorder and its relevance to clinical management. Often referred to as 'relative adrenal insufficiency', a recent consensus conference has proposed the alternate term 'critical illness related corticosteroid insufficiency' and suggested diagnostic criteria of a delta serum cortisol of less than 9 microg/l after adrenocorticotrophic hormone administration or a random total cortisol of under 10 microg/l. This review attempts to establish a critical reappraisal of the evidence for the existence of relative adrenal insufficiency/critical illness related corticosteroid insufficiency in patients with sepsis and examines the background, controversies and possibilities for future research into the condition.

Nonthyroidal illness syndrome and prolonged mechanical ventilation in patients admitted to the ICU

BACKGROUND

The effect of the nonthyroidal illness syndrome (NTIS) on the duration of mechanical ventilation (MV) has not been extensively investigated. This study aims to determine whether the NTIS is associated with the duration of MV in patients admitted to the ICU.

METHODS

We evaluated all patients admitted over a 6-year period to our ICU who underwent invasive MV and had measurement of serum free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) performed in the first 4 days after ICU admission and, subsequently, at least every 8 days during the time they received MV. The primary outcome measure was prolonged MV (PMV), which was defined as dependence on MV for > 13 days.

RESULTS

Two hundred sixty-four patients were included. Fifty-six patients (normal-hormone group) had normal thyroid function test results, whereas 208 patients (low-fT3 group) had, at least in one hormone dosage, low levels of fT3 with normal (n = 145)/low (n = 63) levels of fT4 and normal (n = 189)/low (n = 19) levels of TSH. Patients in the low-fT3 group showed significantly higher mortality and simplified acute physiology score II, and significantly longer duration of MV and ICU length of stay compared with the normal-hormone group. Two of the variables studied were associated with PMV, as follows: the NTIS (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.18 to 4.29; p = 0.01); and the presence of pneumonia (OR, 1.17; 95% CI, 1.06 to 3.01; p = 0.03).

CONCLUSION

The NTIS represents a risk factor for PMV in mechanically ventilated, critically ill patients.

Pituitary-adrenal function in dogs with acute critical illness

OBJECTIVE

To evaluate pituitary-adrenal function in critically ill dogs with sepsis, severe trauma, and gastric dilatation-volvulus (GDV).

DESIGN

Cohort study.

ANIMALS

31 ill dogs admitted to an intensive care unit (ICU) at Washington State University or the University of Pennsylvania; all dogs had acute critical illness for < 48 hours prior to admission.

PROCEDURES

Baseline and ACTH-stimulated serum cortisol concentrations and baseline plasma ACTH concentrations were assayed for each dog within 24 hours after admission to the ICU. The change in cortisol concentrations (Delta-cortisol) was calculated for each dog. Morbidity and mortality data were recorded for each patient.

RESULTS

Overall, 17 of 31 (55%) acutely critically ill dogs had at least 1 biochemical abnormality suggestive of adrenal gland or pituitary gland insufficiency. Only 1 (3%) dog had an exaggerated response to ACTH stimulation. Dogs with Delta-cortisol < or = 83 nmol/L were 5.7 times as likely to be receiving vasopressors as were dogs with Delta-cortisol > 83 nmol/L. No differences were detected among dogs with sepsis, severe trauma, or GDV with respect to mean baseline and ACTH-stimulated serum cortisol concentrations, Delta-cortisol, and baseline plasma ACTH concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Biochemical abnormalities of the hypothalamic-pituitary-adrenal axis indicative of adrenal gland or pituitary gland insufficiency were common in critically ill dogs, whereas exaggerated responses to ACTH administration were uncommon. Acutely ill dogs with Delta-cortisol < or = 83 nmol/L may be more likely to require vasopressors as part of the treatment plan.

Sympathetic modulation of immunity: relevance to disease

Optimal host defense against pathogens requires cross-talk between the nervous and immune systems. This paper reviews sympathetic-immune interaction, one major communication pathway, and its importance for health and disease. Sympathetic innervation of primary and secondary immune organs is described, as well as evidence for neurotransmission with cells of the immune system as targets. Most research thus far has focused on neural-immune modulation in secondary lymphoid organs, has revealed complex sympathetic modulation resulting in both potentiation and inhibition of immune functions. SNS-immune interaction may enhance immune readiness during disease- or injury-induced 'fight' responses. Research also indicate that dysregulation of the SNS can significantly affect the progression of immune-mediated diseases. However, a better understanding of neural-immune interactions is needed to develop strategies for treatment of immune-mediated diseases that are designed to return homeostasis and restore normal functioning neural-immune networks.

A prospective study on adrenal cortex responses and outcome prediction in acute critical illness: results from a large cohort of 203 mixed ICU patients

OBJECTIVE

To assess whether adrenal cortex hormones predict ICU mortality in acute, mixed, critically ill patients.

DESIGN AND SETTING

Prospective study in consecutive intensive care patients in the general ICU of a teaching hospital.

PATIENTS

203 severely ill patients with multiple trauma (n = 93), medical (n = 57), or surgical (n = 53) critical states.

MEASUREMENTS AND RESULTS

Within 24 h of admission in the ICU a morning blood sample was obtained to measure baseline cortisol, corticotropin (ACTH), and dehydropiandrosterone sulfate (DHEAS). Subsequently a low-dose (1 microg) ACTH test was performed to determine stimulated cortisol. The incremental rise in cortisol was defined as stimulated minus baseline cortisol. Overall, 149 patients survived and 54 died. Nonsurvivors were older and in a more severe critical state, as reflected by higher SOFA and APACHE II scores. Nonsurvivors had a lower incremental rise in cortisol (5.0 vs. 8.3 microg/dl and lower DHEAS (1065 vs. 1642 ng/ml) than survivors. The two groups had similar baseline and stimulated cortisol. Multivariate logistic regression analysis revealed that age (odds ratio 1.02), SOFA score (1.36), and the incremental rise in cortisol (0.88) were independent predictors for poor outcome.

CONCLUSIONS

In general ICU patients a blunted cortisol response to ACTH within 24 h of admission is an independent predictor for poor outcome. In contrast, baseline cortisol or adrenal androgens are not of prognostic significance.

Relative adrenal insufficiency: an identifiable entity in nonseptic critically ill patients?

OBJECTIVE

To determine whether relative adrenal insufficiency (RAI) can be identified in nonseptic hypotensive patients in the intensive care unit (ICU).

DESIGN

Retrospective study in a medical-surgical ICU of a university hospital.

PATIENTS

One hundred and seventy-two nonseptic ICU patients (51% after trauma or surgery), who underwent a short 250 microg ACTH test because of > 6 h hypotension or vasopressor/inotropic therapy.

MEASUREMENTS

On the test day, the Simplified Acute Physiology Score II (SAPS II) and Sequential Organ Failure Assessment (SOFA) score were calculated to estimate disease severity. The ICU mortality until day 28 was recorded. Best discriminative levels of baseline cortisol, increases and peaks were established using receiver operating characteristic curves. These and corticosteroid treatment (in n = 112, 65%), among other variables, were examined by multiple logistic regression and Cox proportional hazard regression analyses to find independent predictors of ICU mortality until day 28.

RESULTS

ICU mortality until day 28 was 23%. Nonsurvivors had higher SAPS II and SOFA scores. Baseline cortisol levels correlated directly with albumin levels and SAPS II. In the multivariate analyses, a cortisol baseline > 475 nmol/l and cortisol increase < 200 nmol/l predicted mortality, largely dependent on disease severity but independent of albumin levels. Corticosteroid (hydrocortisone) treatment was not associated with an improved outcome, regardless of the ACTH test results.

CONCLUSION

In nonseptic hypotensive ICU patients, a low cortisol/ACTH response and treatment with corticosteroids do not contribute to mortality prediction by severity of disease. The data thus argue against RAI identifiable by cortisol/ACTH testing and necessitating corticosteroid substitution treatment in these patients.

[The euthyroid sick syndrome in severe acute illness]

OBJECTIVE

To describe euthyroid sick syndrome (ESS) and its different clinical variants in severe acute illness.

DESIGN

This prospective cohort study examined hormone results and outcome for patients admitted to our intensive care unit (ICU).

METHODS

In this heterogeneous group of 108 patients from our ICU we analyzed the prevalence of ESS and its influence on mortality and sought to determine if any thyroid indicators had a prognostic value.

RESULTS

The prevalence of ESS was similar to that described by other authors (68.5% for ESS type I, 15.7% for type II and 1.9% for type III). Patients developed thyroid alterations on their third day of hospitalization and those with ESS type II had a higher mortality rate. The only thyroid indicator with prognostic value was a reverse triiodothyronine (rT3) value exceeding 0.61 ng/mL.

CONCLUSION

Severe acute illness induced the thyroid alterations known as ESS. Type I had the highest prevalence, but type II was correlated with a higher mortality rate. The only thyroid indicator with a prognostic value was rT3.

Clinical review: thyroid hormone replacement in children after cardiac surgery--is it worth a try?

Cardiac surgery using cardiopulmonary bypass produces a generalized systemic inflammatory response, resulting in increased postoperative morbidity and mortality. Under these circumstances, a typical pattern of thyroid abnormalities is seen in the absence of primary disease, defined as sick euthyroid syndrome (SES). The presence of postoperative SES mainly in small children and neonates exposed to long bypass times and the pharmacological profile of thyroid hormones and their effects on the cardiovascular physiology make supplementation therapy an attractive treatment option to improve postoperative morbidity and mortality. Many studies have been performed with conflicting results. In this article, we review the important literature on the development of SES in paediatric postoperative cardiac patients, analyse the existing information on thyroid hormone replacement therapy in this patient group and try to summarize the findings for a recommendation.

Do we have reliable biochemical markers to predict the outcome of critical illness?

Current outcome prediction in critically ill patients relies on the art of clinical judgement and/or the science of prognostication using illness severity scores. The biochemical processes underlying critical illness have increasingly been unravelled. Several biochemical markers reflecting the process of inflammation, immune dysfunction, impaired tissue oxygenation and endocrine alterations have been evaluated for their predictive power in small subpopulations of critically ill patients. However, none of these parameters has been validated in large populations of unselected ICU patients as has been done for the illness severity and organ failure scores. A simple biochemical predictor of ICU mortality will probably remain elusive because the processes underlying critical illness are very complex and heterogeneous. Future prognostic models will need to be far more sophisticated.

Outcome in elderly patients with severe infection is influenced by sex hormones but not gender

OBJECTIVE

The influence of gender as a prognostic variable in patients with severe infections is still controversial. Sex steroid hormones have an important impact on the immune system and vice versa, and prospective studies on the hormonal changes during severe infection are lacking. The objective was to compare the influences of gender and adrenal sex steroid hormone levels on hospital mortality rate in patients with infections.

DESIGN

Prospective observational study conducted between January 1995 and December 2000.

SETTING

University-based level I intensive care unit.

PATIENTS

Included were 208 males and 100 females with severe infection at admission to the ICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mortality rate during hospitalization was analyzed for correlation to gender and the levels of testosterone, 17beta-estradiol, and progesterone; source and clinical signs of infection; Acute Physiology and Chronic Health Evaluation II score; or age. There were no differences in demographic or infectious characteristics between males and females; the survival rate was similar. Males had significantly reduced testosterone levels. Elevation of the steroid hormones 17beta-estradiol (1.5-fold), progesterone (5-fold), and cortisol (1.5-fold) occurred in both genders to the same extent. In addition, testosterone was elevated in septic females and correlated with 17beta-estradiol. Nonsurvivors of both genders had significantly elevated 17beta-estradiol levels. Progesterone was particularly high in nonsurviving males, whereas testosterone was elevated in nonsurviving females. Mortality rate was correlated with high 17beta-estradiol and progesterone in males but with 17beta-estradiol and testosterone in females. Cortisol or dehydroepiandrostenedione sulfate levels were not associated with mortality rates.

CONCLUSIONS

In elderly patients with infections, mortality was not dependent on gender but was correlated with elevated 17beta-estradiol in both genders, with elevated progesterone in males and elevated testosterone in females. Although the latter sex hormones may derive from the adrenals, cortisol levels were only moderately increased and not associated with survival. The high 17beta-estradiol concentrations implicate an increased aromatase activity. Therefore, other pathways of sex steroid production must be involved.

Predictive value of thyroid hormones on the first day in adult respiratory distress syndrome patients admitted to ICU: comparison with SOFA and APACHE II scores

BACKGROUND

Thyroid hormone dysfunction could affect outcome and increase mortality in critical illness. Therefore, in a prospective, observational study we analyzed and compared the prognostic accuracy of free tri-iodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), along with the APACHE II and SOFA scoring systems in predicting intensive care unit (ICU) mortality in critically ill patients.

PATIENTS AND METHODS

Physiology scores were calculated for the first 24 hours after ICU admission in 206 patients with acute respiratory distress syndrome. APACHE II and SOFA scores were employed to determine the initial severity of illness. Thyroid hormones were measured within the first 24 hours. Logistic regression models were created for APACHE II scores, SOFA scores, and thyroid hormone levels. The models predicted high- and low-risk subgroups. Models that showed a good fit were stratified by Kaplan-Meier survival curves.

RESULTS

There were 98 (47.6%) survivors and 108 (52.4%) non-survivors. The survivors had a lower APACHE II score (11.50 vs 15.82, P < 0.0005), a lower SOFA score (6.06 vs 9.42, P < 0.0005), a younger age (57 vs 70 years, P = 0.008), a shorter ICU stay (13 vs 16 days, P = 0.012), and a higher fT3 level (2.18 vs 1.72 pg/mL, P = 0.002) than non-survivors. ICU survival was most closely predicted by a model that included age and fT3 and a model that included APACHE II and APACHE II*sex.

CONCLUSION

In critically ill patients, serum fT3 concentrations markedly decreased after ICU admission among non-survivors. According to our findings, fT3 levels might have additive discriminatory power to age, SOFA and APACHE II scores in predicting short-term mortality in ARDS patients admitted to ICU.

Cortisol changes among patients with septic shock and the relationship to ICU and hospital stay

OBJECTIVE

To evaluate adrenal function in patients with severe sepsis or septic shock.

DESIGN

A prospective study of unstimulated and high-dose ACTH stimulated cortisol levels on days 1 and 2 following ICU admission and day 28 or last day of hospitalization (herein day 28).

SETTING

General intensive care unit.

PATIENTS

34 septic patients.

INTERVENTIONS

On days 1, 2, and 28 of sepsis unstimulated and ACTH stimulated cortisol levels were evaluated. End-points were length of ICU and hospital stay and 28 day all cause mortality.

MEASUREMENTS AND RESULTS

Eight patients on days 1 and 2 had criteria of adrenal insufficiency defined as unstimulated cortisol levels less than 15 microg/dl. Patients with unstimulated cortisol levels less than 15 microg/dl on day 1 or change of 9 microg/dl or less had longer ICU stays. Patients with unstimulated cortisol levels less than 15 microg/dl on day 1 also demonstrated longer hospital stay. On day 1 regression analysis revealed that unstimulated cortisol levels had a significant inverse correlation with length of ICU and hospital stay. The proportional change between unstimulated cortisol and post-ACTH cortisol (Delta%) is a new modality; the higher this Delta% value, the longer is the patient's ICU and hospital stay. A significant positive correlation was found in survivors when comparing unstimulated cortisol vs. day 28 changes.

CONCLUSIONS

The present study highlights the wide range of cortisol levels among patients with sepsis. We observed a difference in cortisol response pattern between survivors and nonsurvivors on day 28. The proportional change between unstimulated cortisol and post-ACTH cortisol was used as a method to evaluate the relative change in cortisol levels between patients.

The Endocrine Response to Critical Illness: Update and Implications for Emergency Medicine

This review will provide an updated overview of the neuroendocrine response to critical illness. Specifically, the current evidence for "stress steroid" administration will be examined, as well as interventional glucose control during critical illness. The emergency physician will also find relevance in the alterations of thyroid hormones that occur in the face of severe illness or trauma.

Thyroid hormone levels improve the prediction of mortality among patients admitted to the intensive care unit

OBJECTIVE

As hormones are strongly associated with mortality in critically ill patients, we investigated whether mortality prediction based on the Acute Physiology and Chronic Health Evaluation (APACHE) is improved by combining this score with hormone measurements.

DESIGN AND SETTING

Intensive care units in three hospitals.

PATIENTS AND PARTICIPANTS

113 patients admitted to.

MEASUREMENTS

Within the first hour after ICU admission we measured total triiodothyronine, total thyroxine, free thyroxine, thyrotropin, cortisol, growth hormone, dehydroepiandrosterone, and prolactin levels and administered the APACHE. Patients were followed until they died or were discharged from the ICU.

RESULTS

The best logistic regression model for ICU mortality included the APACHE score and thyroid-stimulating hormone and triiodothyronine levels. This model had an area under the receiver operating characteristic curve of 0.88, significantly higher than the APACHE score alone with 0.75. The model with hormone levels and APACHE score was also significantly better calibrated than the model with only the APACHE score.

CONCLUSIONS

The addition of thyroid hormones to the APACHE score improves the prediction of mortality for ICU patients.

Thyroid function and ioduria in infants after cardiac surgery: comparison of patients with primary and delayed sternal closure

OBJECTIVES

Thyroid hormone alterations after cardiac surgery may be aggravated by the use of iodine antiseptics. We evaluated thyroid function and ioduria in infants with delayed sternal closure (DSC) who are exposed to povidone-iodine for sternal wound protection and compared them with findings in infants after primary sternal closure.

DESIGN

Prospective clinical study.

SETTING

Pediatric cardiac intensive care unit.

PATIENTS

Ninety-three infants after cardiac surgery using cardiopulmonary bypass, 60 of them with primary sternal closure and 33 of them with delayed sternal closure.

MEASUREMENTS AND MAIN RESULTS

Thyroid hormones were studied in patients with primary sternal closure immediately after surgery, 5 days and 19 days after surgery, in patients with DSC immediately after surgery, immediately after sternal closure, and 2 wks after sternal closure. Ioduria was evaluated on the first, third, and fifth postoperative days after cardiac surgery with primary sternal closure and immediately after DSC. In both groups of patients, low total triiodothyronine, total thyroxine, thyroxine-binding globulin levels, high reverse triiodothyronine levels, and normal free triiodothyronine, free thyroxine, and thyroid-stimulating hormone levels were recorded immediately after surgery. Concentrations of total triiodothyronine and thyroid-stimulating hormone were lower in the patients with DSC. Five days after primary sternal closure and 2 wks after DSC, all thyroid hormone levels were normal for age. Ioduria after DSC was higher than ioduria after primary sternal closure.

CONCLUSIONS

Patients with DSC compared with patients with primary sternal closure display more profound thyroid suppression in the immediate postoperative period. The use of povidone-iodine adhesive drapes with single povidone-iodine mediastinal irrigation in patients with DSC is associated with significant iodine absorption but no significant thyroid dysfunction.

Cytokine dysregulation, inflammation and well-being

Cytokines mediate and control immune and inflammatory responses. Complex interactions exist between cytokines, inflammation and the adaptive responses in maintaining homeostasis, health, and well-being. Like the stress response, the inflammatory reaction is crucial for survival and is meant to be tailored to the stimulus and time. A full-fledged systemic inflammatory reaction results in stimulation of four major programs: the acute-phase reaction, the sickness syndrome, the pain program, and the stress response, mediated by the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Common human diseases such as atopy/allergy, autoimmunity, chronic infections and sepsis are characterized by a dysregulation of the pro- versus anti-inflammatory and T helper (Th)1 versus Th2 cytokine balance. Recent evidence also indicates the involvement of pro-inflammatory cytokines in the pathogenesis of atherosclerosis and major depression, and conditions such as visceral-type obesity, metabolic syndrome and sleep disturbances. During inflammation, the activation of the stress system, through induction of a Th2 shift, protects the organism from systemic 'overshooting' with Th1/pro-inflammatory cytokines. Under certain conditions, however, stress hormones may actually facilitate inflammation through induction of interleukin (IL)-1, IL-6, IL-8, IL-18, tumor necrosis factor-alpha and C-reactive protein production and through activation of the corticotropin-releasing hormone/substance P-histamine axis. Thus, a dysfunctional neuroendocrine-immune interface associated with abnormalities of the 'systemic anti-inflammatory feedback' and/or 'hyperactivity' of the local pro-inflammatory factors may play a role in the pathogenesis of atopic/allergic and autoimmune diseases, obesity, depression, and atherosclerosis. These abnormalities and the failure of the adaptive systems to resolve inflammation affect the well-being of the individual, including behavioral parameters, quality of life and sleep, as well as indices of metabolic and cardiovascular health. These hypotheses require further investigation, but the answers should provide critical insights into mechanisms underlying a variety of common human immune-related diseases.

Role of Corticosteroids in Septic Shock

OBJECTIVE

To highlight the role of relative adrenal insufficiency in the outcome of critically ill patients with sepsis and systematically review the literature regarding the use of corticosteroids for management of severe sepsis/septic shock.

DATA SOURCES

A computerized search of MEDLINE, EMBASE, and the Cochrane Database was undertaken from 1966 to March 2003 using the search terms intensive care unit, critical care, corticosteroids, glucocorticoids, adrenal insufficiency, sepsis, and septic shock. Bibliographies of all articles retrieved were searched for relevant articles not identified by the computerized search.

DATA EXTRACTION/SYNTHESIS

Six trials were identified after publication of the meta-analyses (1995), with a total of 505 patients. The results of these trials in septic shock suggest that low-dose corticosteroids can reduce vasopressor requirements and hasten reversal of shock. Some of these trials suggested a possible mortality benefit from therapy, and no trial demonstrated an increase in mortality or significant adverse effects. The benefit of this therapy may depend on the presence of relative adrenal insufficiency, as identified by the adrenocorticotropic hormone stimulation test.

CONCLUSIONS

Low-dose corticosteroids should be administered to patients with septic shock empirically, but should be discontinued if relative adrenal insufficiency is not confirmed.

Cortisol levels and mortality in severe sepsis

OBJECTIVE

Serum cortisol levels rise in response to the stress of critical illness but the optimal range of serum cortisol in such settings is not clearly defined. The objectives of this study were to determine the range of serum cortisol levels in a group of medical intensive care unit patients with severe sepsis/septic shock using uniform criteria, and to correlate serum cortisol levels to mortality.

DESIGN AND PATIENTS

In a prospective observational fashion, 100 medical intensive care unit patients at Northwestern Memorial Hospital in Chicago were enrolled within 48 h of developing severe sepsis/septic shock as defined by the American College of Chest Physicians/Society of Critical Care Medicine.

MEASUREMENTS

A serum cortisol level was measured during the morning hours in the first 48 h of developing severe sepsis/septic shock. The severity of critical illness was measured by the Acute Physiology and Chronic Health Evaluation II (APACHE II) score.

RESULTS

The average patient age was 63 +/- 17 years, 54 patients were men. The average APACHE II score for all patients was 23 +/- 7. In-hospital and 90-day mortality were 51% and 60%, respectively. Four patient groups were defined a priori based on morning serum cortisol levels and their in-hospital mortalities were as follows: group 1 (cortisol < or = 345 nmol/l), n = 11, mortality 54%; group 2 (cortisol 345-552 nmol/l), n = 19, mortality 53%; group 3 (cortisol 552-1242 nmol/l), n = 54, mortality 41%; and group 4 (cortisol > or = 1242 nmol/l), n = 16, mortality 81% (P < 0.01).

CONCLUSIONS

Cortisol levels were elevated in most patients with septic shock. Cortisol levels less than 552 nmol/l occurred in 30% of patients with septic shock but the mortality in these patients was not significantly increased. Serum cortisol levels > or = 1242 nmol/l were associated with significantly higher mortality.

Glucocorticoids and acute lung injury

OBJECTIVES

To describe hypothalamic-pituitary-adrenal (HPA) activation and the role of glucocorticoids in immune modulation during critical illness, and to review clinical trials of pharmacologic and "replacement"' doses of glucocorticoids in early and late acute respiratory distress syndrome (ARDS) and sepsis.

DATA EXTRACTION AND SYNTHESIS

Selected review of published literature (1963 to present), clinical trials, and meta-analyses.

DATA SUMMARY

HPA axis activation is an important component of the compensatory anti-inflammatory response to critical illness. Cortisol supports vascular tone and endothelial integrity, modulates a large number of proinflammatory cytokines, and suppresses phospholipase A(2), cyclo-oxygenase, and nitric oxide synthase. Cortisol has putative antifibrotic activities, including inhibition of fibroblast growth and collagen deposition and stimulation of T-cell and monocyte apoptosis. During critical illness, neurohumoral factors, cytokines, endothelin, and atrial natriuretic peptide all may participate in HPA axis activation, resulting in elevated plasma cortisol production and plasma concentrations. In general, cortisol concentrations correlate with severity of illness, and higher plasma concentrations are associated with a poorer outcome. Failure of adrenocorticotropic hormone to augment plasma cortisol appears to be a poor prognostic finding in vasopressor-dependent sepsis and may indicate "relative adrenal insufficiency." Replacement glucocorticoid/mineralocorticoid therapy over 7 days appears to be beneficial in such individuals. However, a meta-analysis of high-dose, short-course glucocorticoid treatment involving 1,297 patients with sepsis enrolled in nine trials showed a trend toward harm, and four trials in patients with, or at risk for, ARDS showed no benefit or a greater likelihood of progression to ARDS. In contrast, observational studies and one small randomized controlled trial suggest that lower pharmacologic doses of glucocorticoids given late (>1 wk) in the course of ARDS may be beneficial. The National Heart, Lung, and Blood Institute's ARDS Network currently is testing the use of methylprednisolone in late ARDS. This study was reviewed by an independent data safety monitoring board for safety and efficacy after enrolling 60 and 120 patients and is currently ongoing.

CONCLUSION

Current evidence indicates that short-duration, high-dose glucocorticoid therapy is not effective for early ARDS or severe sepsis. One small randomized, controlled trial suggests that moderate doses of glucocorticoids may be beneficial for patients with late ARDS; a much larger randomized controlled trial is ongoing. Some patients with pressor-dependent severe sepsis appear to have relative adrenal insufficiency and benefit from replacement glucocorticoid/mineralocorticoid therapy. The accuracy of the diagnostic criteria for, and the prevalence of, relative adrenal insufficiency in patients with acute lung injury/ARDS is unknown. It is also unclear whether such a response, if present, predisposes patients to ongoing lung inflammation and the development of late fibroproliferative ARDS, or if it is predictive of a beneficial response to steroids. Studies of HPA axis activation and the role of relative adrenal insufficiency on the outcome of patients with acute lung injury are needed.

Relevance of neuropeptide Y for the neuroimmune crosstalk

Both cellular and humoral functions of the immune system are modulated by the sympathetic nervous system (SNS). This interaction is mainly mediated by the release of catecholamines (CA) and their receptor-specific action on immune cells. However, neuropeptide Y (NPY), also present in sympathetic nerve terminals, is released upon SNS-stimulation. NPY modulates potent immunological effects in vitro and in vivo, such as differentiation of T helper cells, monocyte mediator release, NK cell activation, and immune cell redistribution. In addition to this direct action within the neuroimmune crosstalk, NPY is also able to modulate the immunomodulatory effects of other neurotransmitters, thereby acting as a neuroimmune co-transmitter. This review will discuss key findings from recent studies, provide implications for the clinical situation, and integrate the pleiotropic functions of NPY in the context of neuroimmune interactions.

The adrenal response after severe trauma

BACKGROUND

The integrity of the hypothalamic-pituitary-adrenal axis is a major determinant of the host response to stress. Relative adrenal insufficiency has been implicated in poor outcome from systemic inflammatory states; however, whether low endogenous glucocorticoid levels are adaptive or pathologic remains controversial. The purpose of this study was to prospectively evaluate the cortisol response and determine the incidence of occult adrenal insufficiency after severe trauma.

METHODS

Over an 18-month period, 22 severely injured patients admitted to the surgical intensive care unit of our level 1 trauma center were prospectively identified and followed. Demographic and outcome data were tabulated. In addition, random serum cortisol levels were obtained on days 0, 5, and 10 after injury. Relative adrenal insufficiency was defined as a random serum cortisol level less than 18 microg/dL.

RESULTS

Mean baseline cortisol levels were elevated (35 +/- 3 microg/dL) and significantly declined over the next 10 days (day 5: 24 +/- 2 microg/dL; and day 10: 22 +/- 2 microg/dL; P <0.01). Thirteen of 22 (60%) patients had random serum cortisol levels less than 18 microg/dL. Only 1 of the 2 patients who died had a serum cortisol level less than 18 microg/dL. The mean cortisol levels at baseline were higher in the 2 patients who died compared with those who survived but this was not statistically significant (43.4 +/- 8.8 microg/dL versus 35.0 +/- 3.6 microg/dL, P = 0.5).

CONCLUSIONS

Serum cortisol levels increased immediately and gradually returned towards normal after severe trauma. Occult adrenal insufficiency was common (60%) in this small group of severely injured patients. This did not, however, affect mortality in these patients. Further study is needed to delineate the role of occult adrenal insufficiency after severe injury.

Stress-dose corticosteroid therapy for sepsis and acute lung injury or acute respiratory distress syndrome in critically ill adults

Sepsis and acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) are associated with high mortality rates despite recent therapeutic advances. Both disease states involve uncontrolled host defense responses that lead to inflammation, endothelial damage, enhanced coagulation, diminished fibrinolysis and fibroproliferation to produce microthrombi, and relative adrenal insufficiency. Corticosteroids inhibit the host defense response and may offer an inexpensive therapeutic option. Results of several randomized, double-blind studies demonstrated no survival benefit and higher secondary infection rates when supraphysiologic doses of corticosteroids were administered for less than 24 hours. Recently, the emphasis of research for corticosteroid therapy has involved adrenocortical replacement dosage regimens administered for several days to weeks, with doses corresponding to the stress level of the disease. Stress-dose therapy with hydrocortisone in patients with septic shock who require vasopressor support, especially if adrenal insufficiency is present, accelerates hemodynamic stability and reduces mortality. The frequency of gastrointestinal hemorrhage was higher with corticosteroid therapy than with placebo, but the occurrence of secondary infections was similar to that of placebo. The only randomized, double-blind study that evaluated stress-dose methylprednisolone therapy for ARDS was terminated early after only 24 patients were enrolled because therapy with methylprednisolone was associated with enhanced survival despite higher secondary infection rates. A multicenter study investigating stress-dose methylprednisolone for ARDS is under way and should provide valuable information. Sufficient data support stress-dose hydrocortisone therapy for vasopressor-dependent septic shock. Stress-dose methylprednisolone therapy for ALI-ARDS requires further study but may be warranted in cases of refractory infection-induced ARDS when impending mortality is likely.

Endocrine and metabolic issues in the management of the chronically critically ill patient

The metabolic syndrome of chronic critical illness (CCI) consists of multisystem organ dysfunction resulting from the initial acute injury and chronic immune-neuroendocrine axis activation, adult kwashiorkor-like malnutrition, and prolonged immobilization with suppression of the PTH-vitamin D axis and hyper-resorptive metabolic bone disease. CCI patients can also present unique challenges in the management of diabetes mellitus, thyroid and adrenal diseases, electrolyte abnormalities and hypogonadism.

Pituitary ACTH and adrenocortical secretion in critically ill dogs

OBJECTIVE

To evaluate pituitary-adrenal function in a population of critically ill dogs by measuring serial plasma concentrations of basal cortisol, ACTH-stimulated cortisol, and endogenous ACTH.

DESIGN

Prospective study.

ANIMALS

20 critically ill dogs admitted to an intensive care unit (ICU).

PROCEDURE

Basal plasma cortisol, ACTH-stimulated cortisol, and endogenous ACTH concentrations were measured for each dog within 24 hours of admission and daily until death, euthanasia, or discharge from the ICU. Established reference ranges for healthy dogs were used for comparison. Survival prediction index (SPI) scores were calculated for each dog within 24 hours of admission.

RESULTS

No significant difference was found between initial concentrations of basal cortisol, ACTH-stimulated cortisol, and endogenous ACTH in 13 dogs that survived and those in 7 dogs that died. High initial basal endogenous ACTH concentrations were correlated with subsequent high values. Low basal ACTH-stimulated cortisol concentrations were predictive of higher subsequent values. All basal and ACTH-stimulated cortisol concentrations were within or above the reference range in the 52 plasma samples collected from the 20 dogs during hospitalization. The SPI scores correlated with outcome (ie, alive or dead), but none of the plasma hormone concentrations correlated with SPI score or outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicate that none of the critically ill dogs in our study population developed adrenal insufficiency during hospitalization in the ICU.

Early IL-6 plasma concentrations correlate with severity of brain injury and pneumonia in brain-injured patients

BACKGROUND

Brain injury as well as early inflammatory and endocrine responses were found to be indicators for infectious complications in patients with multiple injuries. In this context, brain-derived inflammatory response as well as centrally triggered neuroendocrine activation and systemic immunodepression seem to be of major importance. Therefore, we hypothesize that a circulating index of inflammatory or endocrine function measured soon after brain injury (in patients with admission Glasgow Coma Scale [GCS] score of 4-7) would discriminate severe from moderate injury as indexed by GCS status on postinjury day 7.

METHODS

In a retrospective study, 25 patients with either acute traumatic brain injury or cerebral hemorrhage and an initial GCS score of 4 to 7 were examined. Blood samples were obtained at different time points, and different immune variables and neuroendocrine hormones were determined. According to the GCS score on day 7, patients were divided into two groups (GCS score > or = 8, moderate brain injury; and GCS score < 8, severe brain injury or patients who died within the first week) for comparison of variables. Concluding from the results of this retrospective analysis, in a prospective study patients (n = 26) were divided into two groups according to their interleukin (IL)-6 plasma concentrations on day 1 (IL-6 > or = 100 pg/mL and IL 6 < 100 pg/mL). After 7 days, the GCS score, the infection rate, and the mortality were compared between these two groups.

RESULTS

In the retrospective study, we could show that severe brain injury (as assessed by GCS score and mortality on day 7) was associated with high plasma levels of pro- and anti-inflammatory cytokines, acute phase proteins, and neuroendocrine hormones within 2 to 6 hours after the acute event. Among the investigated variables, elevated IL-6 plasma concentrations were stable up to 1 day after the acute event with a high predictive value with regard to the short-term prognosis and incidence of infectious complications within the first week. Because of this stability during the first 24 hours, we selected IL-6 for further studies. In the prospective study with a calculated cut-off IL-6 plasma concentration of 100 pg/mL on day 1, the predictive value of this parameter regarding the severity of the brain injury was fully confirmed (positive predictive value, 0.94; this value represents the observed pretest probability of 0.62). All patients who died (n = 5) or developed infectious complications within the first week (n = 8) showed plasma IL-6 levels > or = 100 pg/mL on day 1.

CONCLUSION

The IL-6 plasma level 1 day after the acute event with a cut-off of 100 pg/mL (Immulite) seems to be a predictor for short-term prognosis and infectious complications in brain-injured patients.