Surface and soluble triggering receptor expressed on myeloid cells-1: expression patterns in murine sepsis

OBJECTIVE

To examine the expression patterns of the triggering receptor expressed on myeloid cells (TREM)-1 during experimental septic shock.

DESIGN

Animal study.

SETTING

Animal research laboratory.

SUBJECTS

Male BALB/c mice, 7-9 wks of age.

INTERVENTIONS

Septic shock was induced by cecal ligation and puncture in eight mice. Eight additional animals were sham-operated and served as a control group. All animals were resuscitated by fluid infusion and administered antibiotics. Kill was performed under anesthesia 12, 24, or 48 hrs later.

MEASUREMENTS AND MAIN RESULTS

Surface expression of TREM-1 was analyzed using flow cytometry on peripheral blood cells, peritoneal macrophages and neutrophils, splenic macrophages, and Kupffer cells. Gene expression was also studied in these same cells using reverse transcription-polymerase chain reaction. Tumor necrosis factor-alpha, interleukin-1beta, and soluble TREM-1 concentrations were determined in plasma and peritoneal lavage fluid. Sepsis strongly induced TREM-1 gene expression, which translated into an up-regulation of TREM-1 surface expression on neutrophils and monocytes/macrophages both at the focus on infection as well as distally. Moreover, sepsis induced the release of significant levels of soluble TREM-1. Plasma soluble TREM-1 concentrations negatively correlated with tumor necrosis factor-alpha and interleukin-1beta levels at 12 hrs.

CONCLUSIONS

These results provide new information as to the regulation of TREM-1 during sepsis. Considering that both cell-surface and soluble TREM-1 were strongly up-regulated during infection, this study may add support to the putative usefulness of TREM-1 as a diagnostic tool.

Symptoms of anxiety and depression in family members of intensive care unit patients before discharge or death. A prospective multicenter study

STUDY OBJECTIVES

More than two thirds of family members visiting intensive care unit (ICU) patients have symptoms of anxiety or depression during the first days of hospitalization. Identifying determinants of these symptoms would help caregivers support families at patient discharge or when death is imminent.

DESIGN AND SETTING

Prospective multicenter study including 78 ICUs (1184 beds) in France.

PARTICIPANTS

Family members completed the Hospital Anxiety and Depression Scale on the day of patient discharge or death to allow evaluation of the prevalence and potential factors associated with symptoms of anxiety and depression.

RESULTS

Three hundred fifty-seven patients were included in the study, and 544 family members completed the Hospital Anxiety and Depression Scale. Symptoms of anxiety and depression were found in 73.4% and 35.3% of family members, respectively; 75.5% of family members and 82.7% of spouses had symptoms of anxiety or depression (P = .007). Symptoms of depression were more prevalent in family members of nonsurvivors (48.2%) than of survivors (32.7%) (P = .008). The multivariate model identified 3 groups of factors associated with symptoms: (1) patient-related: severity as assessed by the Simplified Acute Physiology Score II (odds ratio [OR] 1.017 per point) and patient age (OR 0.984 per year) predicted anxiety, and Simplified Acute Physiology Score II (OR, 1.015 per point), patient death (OR 2.092), and patient age (OR 0.981) predicted depression; (2) family-related: the spouse predicted anxiety (OR 2.085); and (3) ICU-related: a room with more than 1 bed (OR 1.539) predicted depression.

CONCLUSION

The prevalence of symptoms of anxiety and depression remains high at the end of the ICU stay, whether the patient is well enough to be discharged or is near death.

Time-course of sTREM (soluble triggering receptor expressed on myeloid cells)-1, procalcitonin, and C-reactive protein plasma concentrations during sepsis

OBJECTIVE

To describe the course of plasma sTREM (soluble triggering receptor expressed on myeloid cells)-1, procalcitonin (PCT), and C-reactive protein (CRP) concentrations during sepsis and their clinical informative value in predicting outcome.

DESIGN

Prospective, noninterventional study.

SETTING

Medical adult intensive care unit at a university hospital in France.

PATIENTS

Sixty-three critically ill patients with sepsis, severe sepsis, or septic shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Soluble TREM-1 concentrations were significantly lower at admission in nonsurvivors (n = 21) than in survivors (n = 42) (94 [30-258] vs. 154 [52-435] pg/mL, p = .02), whereas PCT levels were higher among nonsurvivors (19.2 [0.3-179] vs. 2.4 (0-254) pg/mL, p = .001). CRP levels did not differ between the two groups of patients. Plasma PCT and CRP decreased during the 14-day period of study in both survivors and nonsurvivors. Conversely, sTREM-1 plasma concentrations remained stable or even increased in nonsurviving patients and decreased in survivors. An elevated baseline sTREM-1 level was found to be an independent protective factor with an odds of dying of 0.1 (95% confidence interval, 0.1-0.8).

CONCLUSION

A progressive decline of plasma sTREM-1 concentration indicates a favorable clinical evolution during the recovery phase of sepsis. In addition, baseline sTREM-1 level may prove useful in predicting outcome of septic patients.

Surface triggering receptor expressed on myeloid cells 1 expression patterns in septic shock

OBJECTIVE

To analyze the pattern of cell-surface expression of the triggering receptor expressed on myeloid cells (TREM) 1 during septic shock.

DESIGN AND SETTING

Prospective clinical study in an adult 16-bed medical ICU.

PATIENTS AND METHODS

25 septic shock patients, 15 patients with shock of noninfectious origin and 7 healthy volunteers. Arterial blood was drawn within 12 h of admission and subjected to flow cytometry analysis after staining with anti-TREM-1 and anti-CD14 antibodies. Repeated sampling was performed on days 2, 3, 5, 7, and 14 in septic shock patients.

RESULTS

Monocytic TREM-1 expression was significantly higher in septic shock patients (mean fluorescence intensity 2.3+/-0.2) than in nonseptic patients (1.0+/-0.1), and healthy volunteers (1.0+/-0.1). There was no difference in monocytic TREM-1 expression between nonseptic patients and healthy volunteers or between any of the three groups with respect to TREM-1 expression on neutrophils. The time course of TREM-1 expression on monocytes diverged significantly by day 3 between survivors and ns.

CONCLUSIONS

The specificity of TREM-1 regulation by infection is highlighted. Moreover, surface TREM-1 expression on monocytes may prove useful in allowing the follow-up of septic patients during the course of the disease.

Relation between muscle Na+K+ ATPase activity and raised lactate concentrations in septic shock: a prospective study

BACKGROUND

Hyperlactataemia during septic shock is often viewed as evidence of tissue hypoxia. However, this blood disorder is not usually correlated with indicators of perfusion or diminished with increased oxygen delivery. Muscles can generate lactate under aerobic conditions in a process linking glycolytic ATP supply to stimulation of Na+K+ ATPase. Using in-vivo microdialysis, we tested whether inhibition of Na+K+ ATPase can reduce muscle lactate.

METHODS

In 14 patients with septic shock, two microdialysis probes were inserted into the quadriceps muscles and infused with lactate-free Ringer's solution in the absence or presence of 10(-7) mol/L ouabain, a specific inhibitor of Na+K+ ATPase. We measured lactate and pyruvate concentrations in both the dialysate fluid and arterial blood samples.

FINDINGS

All patients had increased blood lactate concentrations (mean 4.0 mmol/L; SD 2.1). Lactate and pyruvate concentrations were consistently higher in muscle than in arteries during the study period, with a mean positive gradient of 1.98 mmol/L (SD 0.2; p=0.001) and 230 micromol/L (30; p=0.01), respectively. Ouabain infusion stopped over production of muscle lactate and pyruvate (p=0.0001). Muscle lactate to pyruvate ratios remained unchanged during ouabain infusion with no differences between blood and muscle.

INTERPRETATION

Skeletal muscle could be a leading source of lactate formation as a result of exaggerated aerobic glycolysis through Na+K+ ATPase stimulation during septic shock. Lactate clearance as an end-point of resuscitation could therefore prove useful.

RELEVANCE TO CLINICAL PRACTICE

In patients with septic shock, a high lactate concentration should be interpreted as a marker of disease, portending a bad outcome. The presence of hyperlactataemia in resuscitated septic patients should not be taken as proof of oxygen debt needing increases in systemic or regional oxygen transport to supranormal values. Lactate, instead of being regarded only as a marker of hypoxia, might be an important metabolic signal.

Risk factors of relative adrenocortical deficiency in intensive care patients needing mechanical ventilation

OBJECTIVE

To study the factors associated with relative adrenocortical deficiency in mechanically ventilated, critically ill patients.

DESIGN AND SETTING

Prospective observational study in a multidisciplinary ICU of a university-affiliated teaching hospital.

PATIENTS

Sixty-two consecutive, acutely ill patients needing mechanical ventilation for more than 24 h.

MEASUREMENTS AND RESULTS

A high-dose short corticotropin test 24 h after endotracheal intubation. Relative adrenocortical deficiency ("nonresponder" group of patients) was defined by a rise in cortisol less than 90 microg/l after stimulation. Twenty-seven patients were classified as nonresponders and 35 as responders. On univariate analysis nonresponders were more often men, had lower mean arterial pressure, required vasoactive agents more often, had lower creatinine clearance, higher SAPS II, higher organ dysfunction scores, and received etomidate as a single bolus for endotracheal intubation more often than responders. On multivariate analysis, only etomidate administration was related to relative adrenocortical deficiency (OR 12.21; 95% CI 2.99-49.74) while female gender was protective (OR 0.13; 95% CI 0.03-0.57).

CONCLUSIONS

A single bolus infusion of etomidate could be a major risk factor for the development of relative adrenocortical deficiency in ICU patients for at least 24 h after administration. Female gender is an independent protective factor.

Comparison of intravenous and intra-arterial urokinase thrombolysis for acute ischaemic stroke

Intravenous fibrinolysis (IVF) with rt-PA (alteplase) provides significant benefits in acute ischaemic stroke when it is given within the first three hours following stroke onset. Intra-arterial fibrinolysis (IAF) with pro-urokinase in PROACT II study provides quite the same benefit in the first 6 hours. IVF and IAF have never been compared. To compare the efficacy and safety of IVF and IAF with urokinase given within the first 6 hours of acute ischaemic stroke. Patients fulfilling the selection criteria were randomly assigned to receive urokinase 900,000 units via intravenous or intra-arterial routes. This randomised monocentre study was done between December 1995 and August 1997. The primary outcome was defined as the number of patients with a modified Rankin score of 2 or less. Secondary outcomes included mortality, frequency of symptomatic intracranial haemorrhage (SIH), neurological and functional scores. Fourteen patients were given IVF and 13 IAF. The study was terminated by the National Health Authorities when 27 patients had been included because of the mortality rate. Seven patients (26%) died, 4 in the IV group (oedematous infarct in 3 and recurrence in 1), 3 in the IA group (SIH in 2, and oedematous infarct in 1). Patients given IVF were treated significantly earlier (4:16 h vs 5:24 h; p=.007). Although IA patients showed greater and earlier improvement there was no significant difference in primary and secondary outcomes. Because of premature termination, the trial was too small to provide any reliable and conclusive results. Intra-arterial fibrinolysis began significantly later than IV fibrinolysis but it gave non-significantly better results in this prematurely terminated study.

A soluble form of the triggering receptor expressed on myeloid cells-1 modulates the inflammatory response in murine sepsis

The triggering receptor expressed on myeloid cells (TREM)-1 is a recently discovered receptor expressed on the surface of neutrophils and a subset of monocytes. Engagement of TREM-1 has been reported to trigger the synthesis of proinflammatory cytokines in the presence of microbial products. Previously, we have identified a soluble form of TREM-1 (sTREM-1) and observed significant levels in serum samples from septic shock patients but not controls. Here, we investigated its putative role in the modulation of inflammation during sepsis. We observed that sTREM-1 was secreted by monocytes activated in vitro by LPS and in the serum of animals involved in an experimental model of septic shock. Both in vitro and in vivo, a synthetic peptide mimicking a short highly conserved domain of sTREM-1 appeared to attenuate cytokine production by human monocytes and protect septic animals from hyper-responsiveness and death. This peptide seemed to be efficient not only in preventing but also in down-modulating the deleterious effects of proinflammatory cytokines. These data suggest that in vivo modulation of TREM-1 by sTREM peptide might be a suitable therapeutic tool for the treatment of sepsis.

A soluble form of the triggering receptor expressed on myeloid cells-1 modulates the inflammatory response in murine sepsis

The triggering receptor expressed on myeloid cells (TREM)-1 is a recently discovered receptor expressed on the surface of neutrophils and a subset of monocytes. Engagement of TREM-1 has been reported to trigger the synthesis of proinflammatory cytokines in the presence of microbial products. Previously, we have identified a soluble form of TREM-1 (sTREM-1) and observed significant levels in serum samples from septic shock patients but not controls. Here, we investigated its putative role in the modulation of inflammation during sepsis. We observed that sTREM-1 was secreted by monocytes activated in vitro by LPS and in the serum of animals involved in an experimental model of septic shock. Both in vitro and in vivo, a synthetic peptide mimicking a short highly conserved domain of sTREM-1 appeared to attenuate cytokine production by human monocytes and protect septic animals from hyper-responsiveness and death. This peptide seemed to be efficient not only in preventing but also in down-modulating the deleterious effects of proinflammatory cytokines. These data suggest that in vivo modulation of TREM-1 by sTREM peptide might be a suitable therapeutic tool for the treatment of sepsis.

Spectrum of acute allergic diseases in an emergency department: an evaluation of one years' experience

OBJECTIVE

There is limited available literature on the incidence of allergic diseases in ED. The objective of this study was to investigate the clinical records of patients admitted to the ED with a suspected allergic reaction.

METHODS

A 1 year retrospective study was carried out and data were collected from the patients' computerized medical reports.

RESULTS

A total of 324 patients were admitted for an allergic event. Of those, 165 patients (50.9%) were female and their mean age was 55 +/- 18.5 years. Diagnoses included: asthma in 100 patients (30.9%); hymenoptera allergy in 78 patients (24.1%); food allergy in 31 patients (9.5%); drug allergy in 25 patients (7.7%); and allergic conjunctivitis in 12 patients (3.7%). No diagnosis was found in the medical records of 78 patients (24.1%). Anaphylactic shock was observed in 12 patients (3.7%) with a diagnosis of food allergy (six cases), drug allergy (three cases) and hymenoptera allergy (three cases). Ninety patients (27.7%) were hospitalized in the following units: 38 in allergy unit (42.2%); 20 in intensive care unit (22.2%); 10 in pulmonary unit (11.1%); eight in the dermatology unit (8.9%); six in the internal medicine unit (6.7%); and eight in other units (8.9%). Overall, 42 patients (12.9%) were evaluated by an allergologist after ED discharge with positive allergy results in 28 cases (66.6%).

CONCLUSIONS

Acute allergic diseases are not rare in ED, representing 1% of the annual visits in our series. A low rate of allergologist referral was observed. Emergency physicians must work closely with allergologists to ensure a better evaluation, long-term care and preventive management of patients with allergic diseases admitted to the ED.

Plasma level of a triggering receptor expressed on myeloid cells-1: its diagnostic accuracy in patients with suspected sepsis

BACKGROUND

Previous experimental studies have suggested that the triggering receptor expressed on myeloid cells-1 (TREM-1) is specifically upregulated in the presence of microbial products.

OBJECTIVE

To evaluate the diagnostic value of plasma levels of the soluble form of TREM-1 in patients admitted with clinical suspicion of infection.

DESIGN

Prospective, noninterventional study conducted between July and September 2003.

SETTING

Medical adult intensive care unit at a university hospital in France.

PARTICIPANTS

76 consecutive newly admitted patients who presented with clinically suspected infection and fulfilled at least 2 criteria of the systemic inflammatory response syndrome.

MEASUREMENTS

Sensitivity and specificity of plasma soluble TREM-1 levels at admission for the diagnosis of infection. Two independent intensivists blinded to the results of soluble TREM-1 assays retrospectively classified patients as having the systemic inflammatory response syndrome, sepsis, severe sepsis, or septic shock.

RESULTS

The systemic inflammatory response syndrome was diagnosed in 29 patients (38%), and sepsis, severe sepsis, or septic shock was diagnosed in the remaining 47 (62%). A plasma soluble TREM-1 level higher than 60 ng/mL was more accurate than any other clinical or laboratory finding for indicating infection (sensitivity, 96% [95% CI, 92% to 100%]; specificity, 89% [CI, 82% to 95%]; positive likelihood ratio, 8.6 [CI, 3.8 to 21.5]; negative likelihood ratio, 0.04 [CI, 0.01 to 0.2]).

LIMITATIONS

The study did not enroll patients with mild infections not requiring intensive care unit hospitalization, patients older than 80 years of age, or patients who were immunocompromised.

CONCLUSION

In newly admitted critically ill patients, measurement of plasma levels of soluble TREM-1 could help to rapidly identify those with infection.

Soluble triggering receptor expressed on myeloid cells and the diagnosis of pneumonia

BACKGROUND

The diagnosis and treatment of bacterial pneumonia in patients who are receiving mechanical ventilation remain a difficult challenge. The triggering receptor expressed on myeloid cells (TREM-1) is a member of the immunoglobulin superfamily, and its expression on phagocytes is specifically up-regulated by microbial products. The presence of soluble TREM-1 (sTREM-1) in bronchoalveolar-lavage fluid from patients receiving mechanical ventilation may be an indicator of pneumonia.

METHODS

We conducted a prospective study of 148 patients receiving mechanical ventilation in whom infectious pneumonia was suspected. A rapid immunoblot technique was used to measure sTREM-1 in bronchoalveolar-lavage fluid. Two independent intensivists who were unaware of the results of the sTREM-1 assay determined whether community-acquired pneumonia and ventilator-associated pneumonia were present or absent.

RESULTS

The final diagnosis was community-acquired pneumonia in 38 patients, ventilator-associated pneumonia in 46 patients, and no pneumonia in 64 patients. The presence of sTREM-1 by itself was more accurate than any clinical findings or laboratory values in identifying the presence of bacterial or fungal pneumonia (likelihood ratio, 10.38; sensitivity, 98 percent; specificity, 90 percent). In multiple logistic-regression analysis, the presence of sTREM-1 was the strongest independent predictor of pneumonia (odds ratio, 41.5).

CONCLUSIONS

In patients receiving mechanical ventilation, rapid detection of sTREM-1 in bronchoalveolar-lavage fluid may be useful in establishing or excluding the diagnosis of bacterial or fungal pneumonia.

Corticosteroids for treating severe sepsis and septic shock

BACKGROUND

Sepsis may be complicated by impaired corticosteroid production. Giving corticosteroids could potentially benefit patients.

OBJECTIVES

To examine the effects of corticosteroids on death at one month in patients with severe sepsis and septic shock.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group's trial register (August 2003), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2003), MEDLINE (August 2003), EMBASE (August 2003), LILACS (August 2003), reference lists of articles, and also contacted trial authors.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of corticosteroids versus placebo or supportive treatment in severe sepsis and septic shock.

DATA COLLECTION AND ANALYSIS

Two pairs of reviewers agreed the eligibility of trials. One reviewer extracted data, which was checked by the other reviewers and the primary author of the paper whenever possible. We obtained some missing data from the trial authors. We assessed trial methodological quality.

MAIN RESULTS

We identified 15 trials (n =2023). Corticosteroids did not change 28-day all-cause mortality (15 trials, n = 2022, relative risk (RR) 0.92, 95% confidence interval (CI) 0.75 to 1.14; random effects model) and hospital mortality (13 trials, n = 1418, RR 0.89, 95% CI 0.71 to 1.11; random effects model); however, there was statistically significant heterogeneity, with some evidence that this was related to the dosing strategy. Corticosteroids reduced intensive care unit mortality (4 trials, n = 425, RR 0.83, 95% CI 0.70 to 0.97), increased the proportion of shock reversal by day 7 (6 trials, n = 728, RR 1.22, 95% CI 1.06 to 1.40) and by day 28 (4 trials, n = 425, RR 1.26, 95% CI 1.04 to 1.52), without increasing the rate of gastroduodenal bleeding (10 trials, n = 1321, RR 1.16, 95% CI 0.82 to 1.65), superinfection (12 trials, n = 1705, RR 0.93, 95% CI 0.73 to 1.18), and of hyperglycaemia (6 trials, n = 608, RR 1.22, 0.84 to 1.78).

REVIEWER'S CONCLUSIONS

Overall, corticosteroids did not change 28-day mortality and hospital mortality in severe sepsis and septic shock. Long course of low dose corticosteroids reduced 28-day all-cause mortality, and intensive care unit and hospital mortality.

Adult presentation of MCAD deficiency revealed by coma and severe arrythmias

We report the case of a 33-year-old man who presented with headaches and vomiting. Soon after admission he became drowsy and agitated, developed ventricular tachycardia and his neurological state worsened (Glasgow coma score 6). Blood analysis showed respiratory alkalosis, hyperlactacidemia (8 mmol/l), hyperammonemia (390 micro mol/l) and hypoglycaemia (2.4 mmol/l). Subsequently, he developed supraventricular tachycardia, ventricular tachycardia and ultimately ventricular fibrillation resulting in cardiac arrest, which was successfully treated. A CT scan of the head revealed cerebral oedema. Whilst in the intensive care unit, he developed renal failure and rhabdomyolysis. The metabolic abnormalities seen at the time of admission normalised within 48 h with IV glucose infusion. Biological investigations, including urinary organic acids and plasma acylcarnitines, showed results compatible with MCAD deficiency. Mutation analysis revealed the patient was homozygous for the classical mutation A985G. This is one of only a few reports of severe cardiac arrhythmia in an adult due to MCAD deficiency. This condition is probably under-diagnosed in adult patients with acute neurological and/or cardiac presentations.

Comparative effects of dexamethasone and L-canavanine in experimental septic shock

Glucocorticoids can reverse hemodynamic disturbances and dependence on catecholamines in septic shock. The relevant beneficial mechanisms of steroids in septic shock are unknown, although inducible nitric oxide synthase could account for them. The aim of this study was to compare the effects of dexamethasone, a glucocorticoid and L-canavanine, a selective inhibitor of inducible nitric oxide synthase, in a rodent model of sepsis. Mean arterial pressure was restored by dexamethasone and L-canavanine administration at 24 h, no longer at 30 h. Dexamethasone but not L-canavanine improved aortic blood flow at 24 and 30 h. Although both dexamethasone and L-canavanine administration significantly reduced nitrite/nitrate production, and improved survival, steroids did better for survival. In conclusion, dexamethasone and L-canavanine displayed similar vasopressor effects. In addition, steroids improved blood flow suggesting that steroid-induced hemodynamic improvement in sepsis is not solely due to inhibition of inducible nitric oxide synthase.

Opinions about surrogate designation: a population survey in France

OBJECTIVE

Many patients go through periods when they are too ill to give consent or to participate in decisions. When this occurs, patient autonomy is best maintained when a surrogate designated by the patient and familiar with his or her values can speak for the patient. The objective of this study was to determine whether people who are not yet ill are ready to accept surrogate designation. Attitudes toward family participation in care were explored also.

DESIGN

Population survey by telephone. Because refusal of life-sustaining treatment is a dramatic example of patient autonomy, the survey used questions about ICU admission.

SETTING

General population in France.

SUBJECTS

Representative random sample of 8000 residents of France aged 18 yrs or more.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The survey investigated attitudes.

RESULTS

Most respondents said they would like to designate a surrogate (7205 [90%]) and to have their family share in their care (6691 [84%] for bathing, 5629 [70%] for feeding, and 4139 [52%] for tracheal suctioning) and in decisions about their management (6120 [76%]). Among respondents with a spouse, 79% said they would designate the spouse to speak for them. The attitudes were not influenced by ethnicity, religion or education level.

CONCLUSIONS

Most people living in France would want a surrogate to represent them should they be incompetent and admitted to an ICU. Primary care physicians should inform their patients about the benefits of discussing illness-related issues among friends and family.

Effects of epinephrine and norepinephrine on hemodynamics, oxidative metabolism, and organ energetics in endotoxemic rats

OBJECTIVE

To determine whether epinephrine increases lactate concentration in sepsis through hypoxia or through a particular thermogenic or metabolic pathway.

DESIGN

Prospective, controlled experimental study in rats.

SETTING

Experimental laboratory in a university teaching hospital.

INTERVENTIONS

Three groups of anesthetized, mechanically ventilated male Wistar rats received an intravenous infusion of 15 mg/kg Escherichia coli O127:B8 endotoxin. Rats were treated after 90 min by epinephrine ( n=14), norepinephrine ( n=14), or hydroxyethyl starch ( n=14). Three groups of six rats served as time-matched control groups and received saline, epinephrine, or norepinephrine from 90 to 180 degrees min. Mean arterial pressure, aortic, renal, mesenteric and femoral blood flow, arterial blood gases, lactate, pyruvate, and nitrate were measured at baseline and 90 and 180 min after endotoxin challenge. At the end of experiments biopsy samples were taken from the liver, heart, muscle, kidney, and small intestine for tissue adenine nucleotide and lactate/pyruvate measurements.

MEASUREMENTS AND RESULTS

Endotoxin induced a decrease in mean arterial pressure and in aortic, mesenteric, and renal blood flow. Plasmatic and tissue lactate increased with a high lactate/pyruvate (L/P) ratio. ATP decreased in liver, kidney, and heart. The ATP/ADP ratio did not change, and phosphocreatinine decreased in all organs. Epinephrine and norepinephrine increased mean arterial pressure to baseline values. Epinephrine increased aortic blood flow while renal blood low decreased with both drugs. Plasmatic lactate increased with a stable L/P ratio with epinephrine and did not change with norepinephrine compared to endotoxin values. Nevertheless epinephrine and norepinephrine when compared to endotoxin values did not change tissue L/P ratios or ATP concentration in muscle, heart, gut, or liver. In kidney both drugs decreased ATP concentration.

CONCLUSIONS

Our data demonstrate in a rat model of endotoxemia that epinephrine-induced hyperlactatemia is not related to cellular hypoxia.

Gastric capnometry with air-automated tonometry predicts outcome in critically ill patients

CONTEXT

Contrary to tonometer gastric intramucosal pH, there is currently no validated threshold prognostic value for Pco2 gap (tonometer gastric mucosal Pco2 minus arterial Pco2) in the critically ill patient.

OBJECTIVE

To demonstrate a relationship between Pco2 gap and mortality in mechanically ventilated patients.

DESIGN AND SETTING

Inception cohort study from a 9-month prospective survey of 95 consecutively ventilated critically ill patients in a teaching hospital.

PATIENTS

All the ventilated patients of the intensive care unit were included at their admission.

MEASUREMENTS AND MAIN RESULTS

Gastric Pco2 using regional capnometry with air-automated tonometry, arterial gas, lactate, and organ system failure score were measured at admission and after 6, 12, 24, 48, 72, 96, and 120 hrs. For the entire population, the 28-day mortality was 44%. In multivariate analysis, independent predictors of death were organ system failure score (odds ratio, 2.12; 95% confidence interval, 1.02-3.14), 24-hr Pco2 gap (odds ratio, 1.57; 95% confidence interval, 1.10-2.24), and 24-hr lactate (odds ratio, 1.48; 95% confidence interval, 1.06-2.05). We found a threshold value of 20 mm Hg for Pco2 gap and 2.5 mmol/L for lactate, which was associated with a sensitivity of 0.70 and 0.72, respectively, and a specificity of 0.72 and 0.73, respectively.

CONCLUSION

The Pco2 gap is a marker of mortality in ventilated patients in the intensive care unit.

Baseline cortisol levels, cortisol response to corticotropin, and prognosis in late septic shock

The prognostic value of basal and corticotropin-stimulated cortisol concentration in patients with sepsis remains a controversial issue. In a retrospective cohort study, 82 consecutive patients with septic shock underwent a short corticotropin test performed more than 24 h after the onset of vasopressor therapy. Forty-one (50%) patients died within 28 days after the onset of septic shock. The mean (SD) basal cortisol level was 22.7 (10.6) microg/dL. With threshold values of 7 and 9 microg/dL maximal increases in cortisol level, 28 (34%) and 31 (38%) patients were, respectively, classified as nonresponders to the short corticotropin test. On multivariate analysis, a cortisol level >20 microg/dL (P = 0.0002), a maximal response to corticotropin <9 microg/dL (P = 0.044), abnormal lactate values (P = 0.0098), and positive blood cultures (P = 0.004) were independent predictors of 28-day mortality. In conclusion, high basal cortisol and low increase on corticotropin stimulation are predictors of a poor outcome in late septic shock. The underlying mechanisms of these prognostic patterns remain to be elucidated.

Effect of treatment with low doses of hydrocortisone and fludrocortisone on mortality in patients with septic shock

CONTEXT

Septic shock may be associated with relative adrenal insufficiency. Thus, a replacement therapy of low doses of corticosteroids has been proposed to treat septic shock.

OBJECTIVE

To assess whether low doses of corticosteroids improve 28-day survival in patients with septic shock and relative adrenal insufficiency.

DESIGN AND SETTING

Placebo-controlled, randomized, double-blind, parallel-group trial performed in 19 intensive care units in France from October 9, 1995, to February 23, 1999.

PATIENTS

Three hundred adult patients who fulfilled usual criteria for septic shock were enrolled after undergoing a short corticotropin test.

INTERVENTION

Patients were randomly assigned to receive either hydrocortisone (50-mg intravenous bolus every 6 hours) and fludrocortisone (50- micro g tablet once daily) (n = 151) or matching placebos (n = 149) for 7 days.

MAIN OUTCOME MEASURE

Twenty-eight-day survival distribution in patients with relative adrenal insufficiency (nonresponders to the corticotropin test).

RESULTS

One patient from the corticosteroid group was excluded from analyses because of consent withdrawal. There were 229 nonresponders to the corticotropin test (placebo, 115; corticosteroids, 114) and 70 responders to the corticotropin test (placebo, 34; corticosteroids, 36). In nonresponders, there were 73 deaths (63%) in the placebo group and 60 deaths (53%) in the corticosteroid group (hazard ratio, 0.67; 95% confidence interval, 0.47-0.95; P =.02). Vasopressor therapy was withdrawn within 28 days in 46 patients (40%) in the placebo group and in 65 patients (57%) in the corticosteroid group (hazard ratio, 1.91; 95% confidence interval, 1.29-2.84; P =.001). There was no significant difference between groups in responders. Adverse events rates were similar in the 2 groups.

CONCLUSION

In our trial, a 7-day treatment with low doses of hydrocortisone and fludrocortisone significantly reduced the risk of death in patients with septic shock and relative adrenal insufficiency without increasing adverse events.

[Role of plasminogen activators in the treatment of deep venous thrombosis]

In deep vein thrombosis, thrombolytic agents can improve vein patency more rapidly than conventional anticoagulant therapy. The clinical benefit of thrombolytic use would be a reduction in the incidence and severity of the postthrombotic syndrome and limb salvage in "phlegmatia caerulea". A literature review suggests that streptokinase and rt-PA do better than heparin regarding vein patency. A clinical benefit on postthrombotic syndrome can only be suggested by available evidence. The risk of major bleeding is increased by thrombolytic agents as compared with heparin. Mortality for cerebral bleeding is about 0.5%. Currently, thrombolytic therapy is only recommended for limb salvage in phlegmatia caerulea.

Impact of a family information leaflet on effectiveness of information provided to family members of intensive care unit patients: a multicenter, prospective, randomized, controlled trial

Comprehension and satisfaction are relevant criteria for evaluating the effectiveness of information provided to family members of intensive care unit (ICU) patients. We performed a prospective randomized trial in 34 French ICUs to compare comprehension of diagnosis, prognosis, treatment, and satisfaction with information provided by ICU caregivers, in ICU patient family representatives who did (n = 87) or did not (n = 88) receive a family information leaflet (FIL) in addition to standard information. An FIL designed specifically for this study was delivered at the first visit of the family representative: it provided general information on the ICU and hospital, the name of the ICU physician caring for the patient, a diagram of a typical ICU room with the names of all the devices, and a glossary of 12 terms commonly used in ICUs. Characteristics of the ICUs, patients, and family representatives were similar in the two groups. The FIL reduced the proportion of family members with poor comprehension from 40.9% to 11.5% (p < 0.0001). In the representatives with good comprehension, the FIL was associated with significantly better satisfaction (21 [18 to 24, quartiles] versus 27 [24 to 29, quartiles], p = 0.01). These results indicate that ICU caregivers should consider using an FIL to improve the effectiveness of the information they impart to families.

[New techniques in artificial ventilation]

In recent years, considerable improvement has been achieved in the field of mechanical ventilation. A lot of experimental and clinical research has been done to reduce the adverse effects of mechanical ventilation. It is currently of importance that high volumes and pressures have been demonstrated as sources of alveolar-capillary membrane injury in lungs. In the acute respiratory distress syndrome, mechanical ventilator settings have evolved from the goal of strict correction of gas exchange towards a lung-protective strategy where priority is given to tidal volumes limitation and alveolar recruitment. Pressure-assisted ventilatory modes, such as pressure support have been introduced, resulting in better patient-ventilator synchronisation, good tolerance and easier weaning process. Pressure support is also a largely used mode in noninvasive ventilation which has been proved to improve outcome in chronic obstructive pulmonary diseases.