Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine

A review of continuous renal replacement therapy

Patients in the Intensive Care Unit commonly develop acute renal failure (ARF). The kidneys are rarely the only organs failing in these patients. Frequently ARF is part of multiple organ dysfunction syndrome. The choice of dialytic therapy should consider, not only the efficacy of the therapy, but also the undesirable effects such therapy may have on the other failing organs. Intermittent Haemodialysis and Peritoneal Dialysis were the conventional forms of dialysis available. Both are associated with complications which may make them unsuitable for use in the haemodynamically unstable, hypercatabolic patients, seen in the Intensive Care setting. Continuous Renal Replacement Therapy (CRRT) has been introduced in many Intensive Care Units to provide a more stable, flexible form of dialysis. The purpose of this article is to give an overview of the various forms of CRRT and to discuss the advantages of this form of therapy.

A Prediction Rule For Mortality in the Medical Intensive Care Unit Based on Early Acute Organ-System Failure

We evaluated early acute organ-system failure (AOSF) as a predictor of mortality in medical intensive care unit (MICU) patients. Prospective data were obtained on 825 men admitted to a Veterans Administraion (VA) Medical Center MICU. Clinical criteria were used to diagnose the presence of 7 types of AOSF. Of the 2,364 AOSFs detected, 1,847 (78%) were “early” (i.e., detected within the first 48 hours of MICU stay). A random sample of 550 patients was selected for derivation of a prediction rule for MICU mortality based on age and number of early AOSFs. For each additional early AOSF, the adjusted odds of mortality increased by 3.3 (95% confidence interval: 2.7, 4.0; p < 0.0001). When applied to the cross-validation sample of 275 patients, this rule yielded a sensitivity of 77%, a specificity of 86%, and an overall correct classification rate of 82%. These results suggest that a simple rule based on number of AOSFs detected in the early portion of a patient's MICU stay may be a useful predictor of mortality.

The effects of dobutamine therapy in critically ill patients measured by transoesophageal echocardiography and intracardiac monitoring

Fourteen patients with severe hypotension and adult respiratory distress syndrome after trauma (n = 7), general surgery (n = 6) or burns (n = 1) were studied. After volume loading with 6 ml.kg-1 hydroxyethyl starch over 30 min (time I), dobutamine was infused intravenously at 5 micrograms.kg-1.min-1 (time II) and 10 micrograms.kg-1.min-1 (time III). A 5 MHz transoesophageal echocardiographic probe was used to image a standard transgastric short axis view of the left ventricle. Haemodynamic data were obtained from thermodilution studies using pulmonary flotation catheterisation. Echocardiographic measurements (off-line from videotape) and qualitative visual assessment of left ventricular function (visual assessment, on-line) were performed. All measurements were made after fluid replacement, and during infusion of the two dobutamine doses. An improvement in mean systemic arterial blood pressure and mean stroke volume occurred from time I to the end of dobutamine infusion (p < 0.05). All patients, after volume infusion, were normovolaemic according to transoesophageal echocardiography and there was a good correlation between end-diastolic area and stroke volume (r = 0.73). During dobutamine infusion, echocardiographic measurements showed no significant dose-related increase in mean (SD) percentage left ventricular short axis area change from baseline after hydroxyethyl starch (time I: 60 (2); time II: 63 (2); time III: 64 (2)). However, a significant increase in short axis area change was seen in nine of the 14 patients (67%). Analysis of the end-diastolic area/short axis area change relationship revealed a heterogeneous response to dobutamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Corticosteroid rescue treatment of progressive fibroproliferation in late ARDS. Patterns of response and predictors of outcome

Pulmonary fibroproliferation (PFP) is directly or indirectly the leading cause of death in patients with late ARDS. We previously reported our experience using intravenous corticosteroids (IVC) in 8 patients with late ARDS and now have expanded our observation to a total of 25 patients with severe fibroproliferation (mean lung injury score [LIS] 3) and progressive respiratory failure (RF). Thirteen patients had open-lung biopsy before treatment. Patients were started on IVC treatment (IVCT) an average of 15 +/- 7.5 days into mechanical ventilation (MV). Significant physiologic improvement (SPI) to IVCT was defined as a reduction in LIS of greater than 1 point or an increase in PaO2:FIO2 ratio of greater than 100. We observed three patterns of response: rapid responders (RR) had an SPI by day 7 (n = 15); delayed responders (DR) had an SPI by day 14 (n = 6); nonresponders (NR) were without SPI by day 14 (n = 4). Overall the following significant mean changes were seen within 7 days of IVCT: LIS from 3 to 2 (p = 0.001), PaO2:FIO2 from 162 to 234 (p = 0.0004), PEEP from 11 to 6.8 cm H2O (p = 0.001), chest radiograph score from 3.8 to 3.0 (p = 0.009), and VE from 16 to 13.6 L/min (p = 0.01). Development of pneumonia was related to the pattern of response. Surveillance bronchoscopy was effective in identifying pneumonia in eight afebrile patients. Nineteen of 25 (76 percent) patients survived the ICU admission. Comparisons were made between survivors (S) and nonsurvivors (NS) and among the three groups of responders. At the time ARDS developed, no physiologic or demographic variable could discriminate between S and NS. At the time of IVCT, only liver failure was more frequent in nonsurvivors (p = 0.035). Histologic findings at open-lung biopsy and pattern of physiologic response clearly predicted outcome. The presence of preserved alveolar architecture (p = 0.045), myxoid type fibrosis (p = 0.045), coexistent intraluminal bronchiolar fibrosis (p = 0.0045), and lack of arteriolar subintimal fibroproliferation (p = 0.045) separated S from NS. ICU survival rate was 86 percent in responders and 25 percent in nonresponders (p = 0.03). Only one death resulted from refractory respiratory failure.

Decreased production of nitric oxide by human neutrophils during septic multiple organ dysfunction syndrome. Comparison with endotoxin and cytokine effects on normal cells

The objective of this study was to determine nitric oxide (NO) and superoxide anion release (O-2) by neutrophils (PMNs) in the septic multiple organ dysfunction syndrome (MODS) and to compare them with the response of normal cells to lipopolysaccharide (LPS) and cytokines. NO production was measured by the release of nitrites in the medium, its maximal production rate by a modified oxyhemoglobin assay and O-2 by standard methods. Normal cells were incubated with LPS, gamma interferon (IFN-gamma), or tumor necrosis factor (TNF-alpha) alone or in combination. Results showed that PMN release of both NO and O-2 was reduced in septic samples; in contrast, an association of LPS, IFN-gamma, and TNF-alpha promoted maximal NO release by normal cells (40-50%). We conclude that while interaction of normal PMNs with cytokines increases NO and O-2 release, progression of sepsis to a multiple organ dysfunction impairs these responses in both functions.

Critical illness polyneuropathy. A review of the literature, definition and pathophysiology

We present a review of the clinical characteristics, and electromyographical and pathological findings of critical illness polyneuropathy by a comparison of ten studies, leading to a definition. Controversies about the nature of CIP, the interpretation of neurophysiological and pathological findings, and differential diagnoses are discussed.

Proteus mirabilis bacteremia: a review of 176 cases during 1980-1992

Patients with Proteus mirabilis bacteremia at a large community teaching hospital during a 13-year period (1980-1992) were retrospectively reviewed. There were 176 patients whereof 44 (25%) had polymicrobial bacteremia. The median age of patients was 75 years and 64.2% were 70 years or older. Of the patients 56.8% came from a nursing home, 64.2% had an indwelling Foley catheter, and 20.5% nosocomial bacteremia. The most common source of bacteremia was the urinary tract (52.8%) whereas the lower respiratory tract was an uncommon source. Hypotension was present in 30.1% of patients. The overall mortality rate was 29.0% with an attributable mortality rate of 25.6%. The mortality rate of polymicrobial bacteremia (38.6%) was higher than that of monomicrobial bacteremia (25.8%). For patients with monomicrobial bacteremia, significant increase in mortality was found in patients who had nosocomial infection (p < 0.02), whose source of bacteremia was other than the urinary tract (p < 0.01), who had ultimately fatal underlying conditions (p < 0.01), who had hypotension (p < 0.001), who had increase in serum creatinine (p < 0.05), or who had increase in serum bilirubin (p < 0.05).

Evaluation of definitions and parameters for sepsis assessment in patients after cardiac surgery

In 110 patients undergoing elective heart surgery on extracorporeal circulation, various parameters were studied regarding the early assessment of septic complications. In a first step, the Elebute score definition for postoperative sepsis validated in general surgery patients (score > or = 12) could be confirmed in an extended form (> or = 12 on > or = 2 days) for cardiac surgery patients. According to this definition (overall classification accuracy for clinically defined sepsis-related mortality: 94%), septic complications occurred in 16 patients and were associated with a significantly worse prognosis than in non-septic patients (mortality 69% vs. 1%, p < 0.0001). In contrast, SIRS (best classification criterion: positive on > or = 3 days) displayed a lower specificity for clinically defined sepsis-related mortality, at least during the early postoperative course (accuracy: 67%). Based on the Elebute score classification, other more practicable parameters were investigated regarding their usefulness for an early sepsis risk assessment in post cardiac surgical patients. Five additional severity scores (APACHE II, MOF-Goris, HIS, SAPS, SSS) were comparable (ROC area: 0.94 to 0.96) and superior to plasma PMN-elastase and neopterin, haemodynamics and clinical parameters in predicting the risk for septic complications as early as by the first postoperative day.

Acute reversible cardiomyopathy associated with the systemic inflammatory response syndrome

In the absence of ischemic heart disease, severe acute reversible myocardial dysfunction is uncommon, with sepsis most often being implicated in the ICU. We report a 38-year-old woman who developed profound transient myocardial depression due to nonseptic systemic inflammatory response syndrome caused by a necrotic kidney. Hemodynamic parameters and echocardiographic findings improved dramatically following nephrectomy. Other causes of acute myocardial suppression, including electrolyte abnormalities, drugs, catecholamine excess, and endocrine disease were excluded.

Escherichia coli in bacteremia: O-acetylated K1 strains appear to be more virulent than non-O-acetylated K1 strains

A total of 174 blood isolates of Escherichia coli, collected during a 5-year period at the University Hospital Utrecht, were serotyped with rabbit sera against 171 O antigens and 73 capsule (K) antigens. The four most prevalent O-antigen serotypes were O6 (n = 22), O18 (n = 19), O1 (n = 19), and O2 (n = 15). Thirty-one strains were not typeable with any of the O-antigen-typing sera. Of the 148 strains that were subjected to K-antigen serotyping, 34 strains lacked a K antigen and 41 were not typeable with the K-antigen-specific antisera used in the study. K1 was by far the most frequently found K-antigen serotype; this was followed by K2, K53, K5, K13, K7, K(A)28, and K15. Strains possessing a K1 antigen were further classified as either O-acetyl-positive (n = 12) or O-acetyl-negative (n = 21) strains. Retrospective analysis of patients infected with different E. coli isolates--nonencapsulated (n = 23), O-acetylated K1 (n = 12), and non-O-acetylated K1 (n = 21)--revealed clinical differences. More patients suffered from sepsis (94% versus 74%), and a higher rate of mortality was found in the group infected with K1 isolates (18 versus 9%) than in the group infected with nonencapsulated isolates. More patients with severe sepsis (25 versus 10%) and a higher mortality (33 versus 10%) were found in the group infected with O-acetylated K1 isolates than in the group infected with non-O-acetylated isolated. Also, the hospitalization of these patients was prolonged. Thus, O-acetylated E. coli K1 strains seem to be more virulent than non-O-acetylated K1 strains.

Recent developments in our understanding of sepsis: evaluation of anti-endotoxin antibodies and biological response modifiers

Sepsis and septic shock are among the most frequent life-threatening infectious disease problems encountered in emergency medicine practice. This review summarizes the extensive research into the pathophysiology of sepsis, with emphasis on Gram-negative infection. Particular reference is given to the exogenous and endogenous mediators involved in the sepsis cascade. It also critically evaluates new preparations developed to blunt the actions of the exogenous and endogenous mediators responsible for the clinical manifestations comprising this syndrome. Clinical signs likely to be associated with Gram-negative infection are also reviewed, and guidelines are considered for the potential use of newly developed anti-endotoxin antibodies and other biological response modifiers in the treatment of patients with Gram-negative sepsis.

Pneumonia: cause or symptom of postinjury multiple organ failure?

Recent studies have shown that selective gut decontamination can reduce the incidence of pneumonia, but this does not decrease multiple organ failure (MOF) or mortality. These findings have prompted the hypothesis that pneumonia is an inconsequential symptom of MOF. To test this, we prospectively evaluated 123 high-risk trauma patients (mean Injury Severity Score = 36.2 +/- 1.5). Organ dysfunction, scored daily according to a 12-point scale, ultimately developed in 28 (23%) patients. Major infections were diagnosed, based on strict criteria, in 59 patients (48%), and pneumonia developed in 52 patients (43%). Pneumonia was significantly associated with MOF (82% of patients with MOF versus 30% of patients without MOF, p < 0.0001). In 14 (50%) of the patients with MOF, pneumonia preceded a significant rise (greater than or equal to 3) in serial MOF scoring. Of note, 10 (71%) of these patients died. Among the remaining 14 patients with MOF, 10 developed pneumonia, but this was associated with a minimal increase (less than or equal to 2) in MOF scoring (3 patients died). These data, by temporal association with MOF scoring, implicate pneumonia in precipitating or significantly worsening organ failure in 50% of the patients who developed MOF.

Septic shock due to toxoplasmosis in patients infected with the human immunodeficiency virus

PURPOSE

To describe the presentation and clinical course of septic shock due to Toxoplasma gondii in patients infected with the human immunodeficiency virus (HIV).

PATIENTS AND METHODS

From April 1988 to February 1992, nine HIV-infected patients were admitted because of predominant septic shock (7 patients) or developed septic shock in the ICU (2 patients). The recent CD4+ cell count ranged from 2 to 84 x 10(6)/L.

RESULTS

The main clinical features were (1) a history of fever for longer than 15 days, with a recent increase to more than 39.5 degrees C; (2) a recent history of dyspnea (< 15 days, 8 cases; < 7 days, 3 cases); and (3) recent onset of thrombocytopenia (6 of 9 cases). All patients were in shock (hyperkinetic profile in 6 of 7; hypokinetic in 1 of 7), and 8 of 9 were in respiratory distress (ratio of PaO2 over fractional concentration of oxygen in the inspired gas of 117 +/- 23; range, 88 to 155). Chest roentgenograms revealed diffuse alveolar infiltrates in six of nine cases. The serum lactate dehydrogenase (LDH) activity was 6,510 +/- 5,080 IU/L (range, 1,010 to 15,450 IU/L). Serologic tests for T gondii were negative in two cases. Toxoplasma gondii was isolated from lung (9/9), bone marrow (5/7), or blood (2/2). One, 3, and 2 patients had brain, ocular, and myocardial involvement, respectively. No other microbial pathogens were isolated. Seven patients died, 5 less than 3 days after admission.

CONCLUSION

Disseminated toxoplasmosis can cause septic shock in HIV-infected patients. In two cases, the disease was probably a primary infection. The association of high fever, acute dyspnea, recent onset of thrombocytopenia, and a very high level of LDH activity is suggestive of disseminated toxoplasmosis.

Mice lacking the tumour necrosis factor receptor 1 are resistant to TNF-mediated toxicity but highly susceptible to infection by Listeria monocytogenes

Tumour necrosis factor (TNF), jointly referring to TNF alpha and TNF beta, is a central mediator of immune and inflammatory responses; its activities are mediated by two distinct receptors, TNFR1 (p55) and TNFR2 (p75) (reviewed in refs 1-3). The cytoplasmic domains of the TNFRs are unrelated, suggesting that they link to different intracellular signalling pathways. Although most TNF responses have been assigned to one or the other of the TNF receptors (mostly TNFR1), there is no generally accepted model for the physiological role of the two receptor types. To investigate the role of TNFR1 in beneficial and detrimental activities of TNF, we generated TNFR1-deficient mice by gene targeting. We report here that mice homozygous for a disrupted Tnfr1 allele (Tnfr1(0)) are resistant to the lethal effect of low doses of lipopolysaccharide after sensitization with D-galactosamine, but remain sensitive to high doses of lipopolysaccharide. The increased susceptibility of Tnfr1(0)/Tnfr1(0) mutant mice to infection with the facultative intracellular bacterium Listeria monocytogenes indicates an essential role of TNF in nonspecific immunity.

Adult respiratory distress syndrome after radical neck dissection

The clinical management of an unusual case of postoperative ARDS is reported. A few hours following neck surgery and septic insult, the patient developed unexpected ARDS. Aetiologic and supportive treatment were successfully instituted and after 72 hours of intensive therapy, the patient's clinical status improved. The very short time lapse between the septic insult and appearance of ARDS is emphasized. A brief literature review on aetiology, diagnosis and therapy of sepsis, as well as some pertinent aspects concerning the pathogenesis of ARDS and its linkage to sepsis are presented.

Time course of hemostatic abnormalities in sepsis and its relation to outcome

OBJECTIVES

To investigate the time course and the relation to prognosis of coagulation and fibrinolytic abnormalities in patients with septic shock.

PATIENTS AND METHODS

Forty-eight consecutive patients admitted to the medical ICU with the diagnosis of septic shock (diagnosed by defined criteria) were studied. Mortality was 25 of 48. Mean age was 57 +/- 7.3 years. Blood samples were obtained on days 1, 4, and 7 after hospital admission to measure tissue-type plasminogen activator antigen (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitor antigen (PAI-1), plasminogen, alpha 2-antiplasmin, fibrinogen, antithrombin III, protein C, protein S, thrombin-antithrombin complexes (TAT), D-dimer, and von Willebrand factor-related antigen (vWF:Ag).

RESULTS

All patients showed marked abnormalities in both the coagulation and fibrinolytic systems. There were signs of coagulation activation and elevation of both activators and inhibitors of fibrinolysis. Nonsurvivors showed lower levels of protein C and antithrombin III and higher concentration of TAT than survivors. While both t-PA and PAI-1 concentrations were high in survivors and nonsurvivors, only survivors showed a progressive normalization of both parameters during the study period. Low plasminogen levels and plasminogen/alpha 2-antiplasmin ratio were found in both groups, presenting a trend toward normalization only in survivors. The differences reported were not apparent at the time of hospital admission.

CONCLUSIONS

Septic shock is characterized by coagulation activation and fibrinolysis activation and inhibition. Nonsurvivors present a particular hemostatic profile characterized by a more marked activation of coagulation and a more intense inhibition of fibrinolysis. None of the abnormalities studied was significantly different between survivors and nonsurvivors at the time of hospital admission. In the presence of fibrin formation, nonsurvivors present a maintained imbalance in the fibrinolytic response determined by higher PAI-1 plasma concentration, probably contributing to their poor outcome.

Gram-negative sepsis: a dilemma of modern medicine

Gram-negative sepsis is an increasingly common problem, with up to 300,000 cases occurring each year in the United States alone. Despite the ongoing development of new antibiotics, mortality from gram-negative sepsis remains unacceptably high. To stimulate earlier therapeutic intervention by physicians, a new set of broad definitions has been proposed to define the systemic inflammatory response characteristic of sepsis. In this review, the signs and symptoms of this progressive, injurious process are reviewed and its management is discussed, as are the mechanisms by which bacterial endotoxin triggers the biochemical events that lead to such serious complications as shock, adult respiratory distress syndrome, and disseminated intravascular coagulation. These events often occur even when appropriate antimicrobial therapy has been instituted. An increased understanding of the structure of endotoxin and its role in the development of sepsis, together with advances in hybridoma technology, has led to the development of monoclonal antibodies that bind to endotoxin and significantly attenuate its adverse effects. These agents promise to substantially reduce the morbidity and mortality associated with gram-negative sepsis.