Cardiovascular management of septic shock

VASOPRESSIN MEDIATES THE PRESSOR EFFECT OF HYPERTONIC SALINE SOLUTION IN ENDOTOXIC SHOCK

The administration of lipopolysaccharide (LPS) to experimental animals results in a septic shock-like syndrome characterized by hypotension, and the hemodynamic management includes the restoration of adequate tissue perfusion by administration of resuscitation fluids to achieve an effective circulating volume. In the present study, we sought to investigate the effects of hypertonic saline solution administration on vasopressin secretion and mean arterial pressure in endotoxic shock. The pressor response to isotonic saline solution (0.9% sodium chloride) or hypertonic saline (7.5% sodium chloride, 4 mL/kg i.v.) was evaluated 4 h after LPS (1.5 mg/kg) administration. At this moment, plasma vasopressin did not differ from control; however, the blood pressure was lower in the LPS-treated group. The hypertonic saline administration was followed by an immediate recovery of blood pressure and also by an increase in plasma vasopressin levels compared with isotonic saline solution. The vasopressin V1 receptor antagonist (10 microg/kg, i.v., 5 min before infusion) blocked the pressor response to hypertonic saline solution. These data suggest that the recovery of blood pressure after hypertonic saline solution administration during endotoxic shock is mediated by vasopressin secretion.

Addition of Vasopressin to Norepinephrine as Independent Predictor of Mortality in Patients with Refractory Septic Shock: An Observational Study

OBJECTIVE

To identify predictors of 28-day mortality among patients with refractory septic shock treated with norepinephrine with or without vasopressin.

DESIGN

Prospective observational cohort study.

SETTING

A 1,200-bed academic medical center.

PATIENTS

One hundred thirty-seven patients with septic shock treated with norepinephrine with or without vasopressin.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 28-day mortality rate was 37.2% (n = 51). By multivariate analysis, significant predictors of death were norepinephrine plus vasopressin administration (adjusted odds ratio [AOR], 13.96; 95% confidence interval [CI] 6.47, 30.08; p = 0.001), lack of goal-directed fluid administration during initial resuscitation (AOR 15.82; 95% CI 6.16, 40.61; p = 0.003), inappropriate initial antimicrobial therapy (AOR 8.95; 95% CI 2.93, 27.33; p = 0.05), and higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (AOR 1.14; 95% CI 1.07, 1.21; p = 0.033). Patients who received norepinephrine plus vasopressin (n = 68) had a significantly higher mortality rate than patients managed with norepinephrine alone (n = 69) 28 days after the initiation of vasopressors (54.4% vs. 20.3%; p < 0.001). This finding was confirmed in patients matched optimally across treatment groups.

CONCLUSIONS

Our study found an association between the use of norepinephrine plus vasopressin and 28-day mortality in refractory septic shock. In view of its known mechanism of action, vasopressin contributed to this excess mortality. Further recommendations regarding the use of vasopressin await the results of large randomized trials evaluating its efficacy and safety for septic shock.

Physiological Monitoring for Critically Ill Patients: Testing a Predictive Model for the Early Detection of Sepsis

• Objective To assess the predictive value for the early detection of sepsis of the physiological monitoring parameters currently recommended by the Surviving Sepsis Campaign.

• Methods The Project IMPACT data set was used to assess whether the physiological parameters of heart rate, mean arterial pressure, body temperature, and respiratory rate can be used to distinguish between critically ill adult patients with and without sepsis in the first 24 hours of admission to an intensive care unit.

• Results All predictor variables used in the analyses differed significantly between patients with sepsis and patients without sepsis. However, only 2 of the predictor variables, mean arterial pressure and high temperature, were independently associated with sepsis. In addition, the temperature mean for hypothermia was significantly lower in patients without sepsis. The odds ratio for having sepsis was 2.126 for patients with a temperature of 38°C or higher, 3.874 for patients with a mean arterial blood pressure of less than 70 mm Hg, and 4.63 times greater for patients who had both of these conditions.

• Conclusions The results support the use of some of the guidelines of the Surviving Sepsis Campaign. However, the lowest mean temperature was significantly less for patients without sepsis than for patients with sepsis, a finding that calls into question the clinical usefulness of using hypothermia as an early predictor of sepsis. Alone the group of variables used is not sufficient for discriminating between critically ill patients with and without sepsis.

Analysis of the evidence for the lower limit of systolic and mean arterial pressure in children

OBJECTIVE

Systolic blood pressure (SBP) and mean arterial pressure (MAP) are essential evaluation elements in ill children, but there is wide variation among different sources defining systolic hypotension in children, and there are no normal reference values for MAP. Our goal was to calculate the 5th percentile SBP and MAP values in children from recently updated data published by the task force working group of the National High Blood Pressure Education Program and compare these values with the lowest limit of acceptable SBP and MAP defined by different sources.

DESIGN

Mathematical analysis of clinical database.

METHODS

The 50th and 95th percentile SBP values from task force data were used to derive the 5th percentile value for children from 1 to 17 yrs of age stratified by height percentiles. MAP values were calculated using a standard mathematical formula. Calculated SBP values were compared with systolic hypotension definitions from other sources. Linear regression analysis was applied to create simple formulas to estimate 5th percentile SBP and 5th and 50th percentile MAP for different age groups at the 50th height percentile.

RESULTS

A 9-21% range in both SBP and MAP values was noted for different height percentiles in the same age groups. The 5th percentile SBP values used to define hypotension by different sources are higher than our calculated values in children but are lower than our calculated values in adolescents. Clinical formulas for calculation of SBP and MAP (mm Hg) in normal children are as follows: SBP (5th percentile at 50th height percentile) = 2 x age in years + 65, MAP (5th percentile at 50th height percentile) = 1.5 x age in years + 40, and MAP (50th percentile at 50th height percentile) = 1.5 x age in years + 55.

CONCLUSION

We developed new estimates for values of 5th percentile SBP and created a table of normal MAP values for reference. SBP is significantly affected by height, which has not been considered previously. Although the estimated lower limits of SBP are lower than currently used to define hypotension, these values are derived from normal healthy children and are likely not appropriate for critically ill children. Our data suggest that the current values for hypotension are not evidence-based and may need to be adjusted for patient height and, most important, for clinical condition. Specifically, we suggest that the definition of hypotension derived from normal children should not be used to define the SBP goal; a higher target SBP is likely appropriate in many critically ill and injured children. Further studies are needed to evaluate the appropriate threshold values of SBP for determining hypotension.

Terlipressin: vasopressin analog and novel drug for septic shock

OBJECTIVE

To review and assess available literature on chemistry, pharmacology, pharmacodynamics, pharmacokinetics, clinical studies, adverse events, drug interactions, and dosing and administration of terlipressin in septic shock.

DATA SOURCES

A literature search of MEDLINE (1966-September 2006), International Pharmaceutical Abstracts (1970-September 2006), and Cochrane database (third quarter 2006) was conducted, using key terms of terlipressin, lypressin, triglycyl-lysine vasopressin, hemodynamic support, septic shock, vasopressor, and V1 receptor agonist. Bibliographies of relevant articles were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

Available English-language literature, including abstracts, animal studies, preclinical studies, clinical trials, and review articles, were examined.

DATA SYNTHESIS

Because of potentially favorable pharmacokinetics versus vasopressin and limited availability of vasopressin in some countries, the effects of terlipressin, a vasopressin analog, have been studied recently for the treatment of septic shock. When administered as a 1-2 mg intravenous dose in patients with septic shock, terlipressin increases mean arterial pressure, urine output, systemic vascular resistance index, pulmonary vascular resistance index, and left and right ventricular stroke work index while decreasing heart rate, cardiac output, lactate, and oxygen delivery and consumption index. It is unclear whether lower doses of terlipressin would produce a similar vasopressor response with fewer cardiopulmonary effects and whether the effects of the drug on oxygen transport indices are detrimental.

CONCLUSIONS

Terlipressin is a promising investigational medication for treatment of septic shock. Small trials have shown terlipressin to have favorable effects on hemodynamics in patients with septic shock refractory to conventional vasopressor treatment. It should be used with extreme caution in patients with underlying cardiac or pulmonary dysfunction. Further studies are needed to verify safety, efficacy, and dosing of terlipressin in patients with septic shock, and its use cannot be recommended in lieu of vasopressin at this time.

Comparison of buccal microcirculation between septic and hemorrhagic shock

OBJECTIVE

Microcirculatory perfusion is disturbed in sepsis, and global hemodynamics does not necessarily reflect microcirculatory blood flow. In this study, we investigated the effect of the same level of mean arterial pressure (MAP) or cardiac index on the changes in buccal microcirculation between septic and hemorrhagic shock.

DESIGN

Prospective, controlled laboratory study.

SETTING

University-affiliated research laboratory.

INTERVENTIONS

A total of 20 Sprague-Dawley rats were divided into four groups: 1) septic shock induced by cecal ligation and perforation: when MAP decreased to 80 mm Hg, saline was infused at a rate of 25 mL.kg.hr for 2 hrs; 2) both time- and MAP-matched hemorrhagic shock: approximately 30% of total blood volume was withdrawn during the corresponding interval, followed by infusion aiming to restore MAP as required when MAP decreased to 80 mm Hg; 3) both time- and cardiac index-matched hemorrhagic shock: approximately 40% of total blood volume was withdrawn during the corresponding interval until MAP decreased to 50 mm Hg, which generally generated a cardiac index similar to those in septic animals, followed by infusion at the same rate for 2 hrs; and 4) sham control: animals underwent the same procedure except no cecal ligation and perforation, bleeding, and infusion.

MEASUREMENTS AND MAIN RESULTS

Buccal microcirculation was visualized with the aid of an orthogonal polarization spectral image device. A semiquantitative score was calculated for vessels of <20 mum, primarily representing the capillaries. Impaired buccal capillary blood flows in septic animals were more severe than those in MAP-matched hemorrhagic animals and were similar to those in cardiac index-matched hemorrhagic animals during the hypoperfusion period before infusion. Significantly improved global hemodynamics after resuscitation cannot effectively improve the buccal capillary blood flows in septic animals, in contrast to those in MAP-matched and cardiac index-matched hemorrhagic animals.

CONCLUSIONS

Impaired microcirculatory alteration in septic shock is more severe than hemorrhagic shock; microcirculation is relatively independent of improved systemic hemodynamics, in contrast to those in hemorrhagic shock.

Arterial Versus Plethysmographic Dynamic Indices to Test Responsiveness for Testing Fluid Administration in Hypotensive Patients: A Clinical Trial

In the present study, we compared indices of respiratory-induced variation obtained from direct arterial blood pressure measurement with analogous indices obtained from the plethysmogram measured by the pulse oximeter to assess the value of these indices for predicting the cardiac output increase in response to a fluid challenge. Thirty-two fluid challenges were performed in 22 hypotensive patients who were also monitored with a pulmonary artery catheter. Hemodynamic and plethysmographic data were collected before and after intravascular volume expansion. Patients were classified as nonresponders if their cardiac index did not increase by 15% from baseline. Nonresponding patients had both lower arterial pulse variation ([10 +/- 4]% vs [19 +/- 13]%, P = 0.020) and lower plethysmographic pulse variation ([12 +/- 7]% vs [21 +/- 14]%, P = 0.034) when compared with responders. Fluid responsiveness was similarly predicted by arterial and plethysmographic pulse variations (area under ROC curve 0.74 vs 0.72, respectively, P = 0.90) and by arterial and plethysmographic systolic variation (area under ROC curve 0.64 vs 0.72, respectively, P = 0.50). Nonresponders were identified by changes in pulse variation both on arterial and plethysmographic waveform (area under ROC curve 0.80 vs 0.87, respectively, P = 0.40) and by changes in arterial and plethysmographic systolic variations (area under ROC curve 0.84 vs 0.80, respectively, P = 0.76). In the population studied, plethysmographic dynamic indices of respiratory-induced variation were just as useful for predicting fluid responsiveness as the analogous indices derived from direct arterial blood pressure measurement. These plethysmographic indices could provide a noninvasive tool for predicting the cardiac output increase by administering fluid.

Dopexamine and norepinephrine versus epinephrine on gastric perfusion in patients with septic shock: a randomized study [NCT00134212]

Introduction

Microcirculatory blood flow, and notably gut perfusion, is important in the development of multiple organ failure in septic shock. We compared the effects of dopexamine and norepinephrine (noradrenaline) with those of epinephrine (adrenaline) on gastric mucosal blood flow (GMBF) in patients with septic shock. The effects of these drugs on oxidative stress were also assessed.

Methods

This was a prospective randomized study performed in a surgical intensive care unit among adults fulfilling usual criteria for septic shock. Systemic and pulmonary hemodynamics, GMBF (laser-Doppler) and malondialdehyde were assessed just before catecholamine infusion (T₀), as soon as mean arterial pressure (MAP) reached 70 to 80 mmHg (T₁), and 2 hours (T₂) and 6 hours (T₃) after T₁. Drugs were titrated from 0.2 μg kg^-1 min^-1 with 0.2 μg kg^-1 min^-1 increments every 3 minutes for epinephrine and norepinephrine, and from 0.5 μg kg^-1 min^-1 with 0.5 μg kg^-1 min^-1 increments every 3 minutes for dopexamine.

Results

Twenty-two patients were included (10 receiving epinephrine, 12 receiving dopexamine–norepinephrine). There was no significant difference between groups on MAP at T₀, T₁, T₂, and T₃. Heart rate and cardiac output increased significantly more with epinephrine than with dopexamine–norepinephrine, whereas. GMBF increased significantly more with dopexamine–norepinephrine than with epinephrine between T₁ and T₃ (median values 106, 137, 133, and 165 versus 76, 91, 90, and 125 units of relative flux at T₀, T₁, T₂ and T₃, respectively). Malondialdehyde similarly increased in both groups between T₁ and T₃.

Conclusion

In septic shock, at doses that induced the same effect on MAP, dopexamine–norepinephrine enhanced GMBF more than epinephrine did. No difference was observed on oxidative stress.

Before–after study of a standardized hospital order set for the management of septic shock*

OBJECTIVE

To evaluate a standardized hospital order set for the management of septic shock in the emergency department.

DESIGN

Before-after study design with prospective consecutive data collection.

SETTING

Emergency department of a 1,200-bed academic medical center.

PATIENTS

A total of 120 patients with septic shock.

INTERVENTIONS

Implementation of a standardized hospital order set for the management of septic shock.

MEASUREMENTS AND MAIN RESULTS

A total of 120 consecutive patients with septic shock were identified. Sixty patients (50.0%) were managed before the implementation of the standardized order set, constituting the before group, and 60 (50.0%) were evaluated after the implementation of the standardized order set, making up the after group. Demographic variables and severity of illness measured by the Acute Physiology and Chronic Health Evaluation II were similar for both groups. Patients in the after group received statistically more intravenous fluids while in the emergency department (2825 +/- 1624 mL vs. 3789 +/- 1730 mL, p = .002), were more likely to receive intravenous fluids of >20 mL/kg body weight before vasopressor administration (58.3% vs. 88.3%, p < .001), and were more likely to be treated with an appropriate initial antimicrobial regimen (71.7% vs. 86.7%, p = .043) compared with patients in the before group. Patients in the after group were less likely to require vasopressor administration at the time of transfer to the intensive care unit (100.0% vs. 71.7%, p < .001), had a shorter hospital length of stay (12.1 +/- 9.2 days vs. 8.9 +/- 7.2 days, p = .038), and a lower risk for 28-day mortality (48.3% vs. 30.0%, p = .040).

CONCLUSIONS

Our study found that the implementation of a standardized order set for the management of septic shock in the emergency department was associated with statistically more rigorous fluid resuscitation of patients, greater administration of appropriate initial antibiotic treatment, and a lower 28-day mortality. These data suggest that the use of standardized order sets for the management of septic shock should be routinely employed.

Adrenal insufficiency in patients with cirrhosis and septic shock: Effect of treatment with hydrocortisone on survival

Relative adrenal insufficiency is frequent in patients with severe sepsis and is associated with hemodynamic instability, renal failure, and increased mortality. This study prospectively evaluated the effects of steroids on shock resolution and hospital survival in a series of 25 consecutive patients with cirrhosis and septic shock (group 1). Adrenal function was evaluated by the short corticotropin test within the first 24 hours of admission. Patients with adrenal insufficiency were treated with stress doses of intravenous hydrocortisone (50 mg/6 h). Data were compared to those obtained from the last 50 consecutive patients with cirrhosis and septic shock admitted to the same intensive care unit in whom adrenal function was not investigated and who did not receive treatment with steroids (group 2). Incidence of adrenal insufficiency in group 1 was 68% (17 patients). Adrenal dysfunction was frequent in patients with advanced cirrhosis (Child C: 76% vs. Child B: 25%, P = .08). Resolution of septic shock (96% vs. 58%, P = .001), survival in the intensive care unit (68% vs. 38%, P = .03), and hospital survival (64% vs. 32%, P = .003) were significantly higher in group 1. The main causes of death in group 1 were hepatorenal syndrome or liver failure (7 of 9 patients). In contrast, refractory shock caused most of the deaths in group 2 (20 of 34 patients). In conclusion, relative adrenal insufficiency is very frequent in patients with advanced cirrhosis and septic shock. Hydrocortisone administration in these patients is associated with a high frequency of shock resolution and high survival rate.

Antimicrobial treatment of sepsis

BACKGROUND

Sepsis is a major cause of morbidity and death in hospitalized patients worldwide and one of the largest current challenges in critical care.

METHOD

Review of the pertinent English-language literature.

RESULTS

Treatment goals conventionally have included maintenance of systemic perfusion and eradication of sources of infection. Initial empiric antimicrobial regimen should be broad enough to cover all likely pathogens, as there is little margin for error in critically ill patients.

CONCLUSION

A multidisciplinary team, including the critical care physician, the microbiologist, the infectious disease specialist, the surgeon, and the clinical pharmacologist, is necessary for optimal patient outcome.

Sepsis-associated myocardial dysfunction: diagnostic and prognostic impact of cardiac troponins and natriuretic peptides

Myocardial dysfunction, which is characterized by transient biventricular impairment of intrinsic myocardial contractility, is a common complication in patients with sepsis. Left ventricular systolic dysfunction is reflected by a reduced left ventricular stroke work index or, less accurately, by an impaired left ventricular ejection fraction (LVEF). Early recognition of myocardial dysfunction is crucial for the administration of the most appropriate therapy. Cardiac troponins and natriuretic peptides are biomarkers that were previously introduced for diagnosis and risk stratification in patients with acute coronary syndrome and congestive heart failure, respectively. However, their prognostic and diagnostic impact in critically ill patients warrants definition. The elevation of cardiac troponin levels in patients with sepsis, severe sepsis, or septic shock has been shown to indicate left ventricular dysfunction and a poor prognosis. Troponin release in this population occurs in the absence of flow-limiting coronary artery disease, suggesting the presence of mechanisms other than thrombotic coronary artery occlusion, probably a transient loss in membrane integrity with subsequent troponin leakage or microvascular thrombotic injury. In contrast to the rather uniform results of studies dealing with cardiac troponins, the impact of raised B-type natriuretic peptide (BNP) levels in patients with sepsis is less clear. The relationship between BNP and both LVEF and left-sided filling pressures is weak, and data on the prognostic impact of high BNP levels in patients with sepsis are conflicting. Mechanisms other than left ventricular wall stress may contribute to BNP release, including right ventricular overload, catecholamine therapy, renal failure, diseases of the CNS, and cytokine up-regulation. Whereas cardiac troponins may be integrated into the monitoring of myocardial dysfunction in patients with severe sepsis or septic shock to identify those patients requiring early and aggressive supportive therapy, the routine use of BNP and other natriuretic peptides in this setting is discouraged at the moment.

Adrenal insufficiency in patients with cirrhosis, severe sepsis and septic shock

Patients with cirrhosis are susceptible to bacterial infection, which can result in circulatory dysfunction, renal failure, hepatic encephalopathy, and a decreased survival rate. Severe sepsis is frequently associated with adrenal insufficiency, which may lead to hemodynamic instability and a poor prognosis. We evaluated adrenal function using short corticotropin stimulation test (SST) in 101 critically ill patients with cirrhosis and severe sepsis. Adrenal insufficiency occurred in 51.48% of patients. The patients with adrenal insufficiency had a higher hospital mortality rate when compared with those with normal adrenal function (80.76% vs. 36.7%, P < .001). The cumulative rates of survival at 90 days were 15.3% and 63.2% for the adrenal insufficiency and normal adrenal function groups, respectively (P < .0001). The hospital survivors had a higher cortisol response to corticotropin (16.2 +/- 8.0 vs. 8.5 +/- 5.9 microg/dL, P < .001). The cortisol response to corticotropin was inversely correlated with various disease severity, Model for End-Stage Liver Disease, and Child-Pugh scores. Acute physiology, age, chronic health evaluation III score, and cortisol increment were independent factors to predict hospital mortality. Mean arterial pressure on the day of SST was lower in patients with adrenal insufficiency (60 +/- 14 vs. 74.5 +/- 13 mm Hg, P < .001), and a higher proportion of these patients required vasopressors (73% vs. 24.48%, P < .001). Mean arterial pressure, serum bilirubin, vasopressor dependency, and bacteremia were independent factors that predicted adrenal insufficiency. In conclusion, adrenal insufficiency is common in critically ill patients with cirrhosis and severe sepsis. It is related to functional liver reserve and disease severity and is associated with hemodynamic instability, renal dysfunction, and increased mortality.

[Non-infective treatments for septic shock]

"Severe sepsis" is defined by organ dysfunction due to infection-induced hypoperfusion. "Septic shock" is defined by hypotension refractory to fluid resuscitation, associated with organ dysfunctions or hypoperfusion. Mortality from severe sepsis and from septic shock is high. Guidelines to help physicians improve the survival of patients with severe sepsis comprise one part of an international project called the Surviving Sepsis Campaign. They bring together treatment innovations based on monitoring aimed at ensuring comprehensive management of tissue oxygen levels (central venous oxygen saturation: SvcO2). They are based on the optimization of early treatment, during the first six hours of severe sepsis, and ensuring no delay in fluid resuscitation. In case of septic shock, fluid resuscitation must be rapidly accompanied by administration of vasoconstrictive catecholamines. Noradrenaline is preferred to dopamine. Dobutamine is recommended when the cardiac index is less than 2.5 L x min(-1) x m(-2). Because of the relative adrenal insufficiency that occurs during septic shock, corticoids are recommended, after a synacthen test. Activated protein C is currently the only therapy produced by biotechnology that reduces mortality from severe sepsis. Global management of septic shock must form an integral part of resuscitation guidelines and include protocols for, among other things, sedation, ventilation, strict glycemic control, and prophylaxis for deep vein thrombosis and stress ulcers.

Low cardiac output syndrome: identification and management

Low cardiac output syndrome (LCOS) is a clinical condition that is caused by a transient decrease in systemic perfusion secondary to myocardial dysfunction. The outcome is an imbalance between oxygen delivery and oxygen consumption at the cellular level which leads to metabolic acidosis. Although LCOS is observed most commonly in patients after cardiac surgery, it may present in various disease processes resulting in cardiac dysfunction. This article provides an overview of the determinants involved in oxygen transport, the physiologic factors influencing cardiovascular function, the assessment of hemodynamic variables, the etiology of LCOS, and management strategies, including a brief review of some pharmacologic agents that are used in the treatment of low cardiac output.

Sepsis progression and outcome: a dynamical model

Background

Sepsis (bloodstream infection) is the leading cause of death in non-surgical intensive care units. It is diagnosed in 750,000 US patients per annum, and has high mortality. Current understanding of sepsis is predominately observational and correlational, with only a partial and incomplete understanding of the physiological dynamics underlying the syndrome. There exists a need for dynamical models of sepsis progression, based upon basic physiologic principles, which could eventually guide hourly treatment decisions.

Results

We present an initial mathematical model of sepsis, based on metabolic rate theory that links basic vascular and immunological dynamics. The model includes the rate of vascular circulation, a surrogate for the metabolic rate that is mechanistically associated with disease progression. We use the mass-specific rate of blood circulation (SRBC), a correlate of the body mass index, to build a differential equation model of circulation, infection, organ damage, and recovery. This introduces a vascular component into an infectious disease model that describes the interaction between a pathogen and the adaptive immune system.

Conclusion

The model predicts that deviations from normal SRBC correlate with disease progression and adverse outcome. We compare the predictions with population mortality data from cardiovascular disease and cancer and show that deviations from normal SRBC correlate with higher mortality rates.

Serum vasopressin concentrations in critically ill patients*

OBJECTIVE

To measure arginine vasopressin (AVP) serum concentrations in critically ill patients.

DESIGN

Prospective study.

SETTING

Twelve-bed general and surgical intensive care unit in a tertiary, university teaching hospital.

PATIENTS

Two-hundred-thirty-nine mixed critically ill patients and 70 healthy volunteers.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic data, hemodynamic variables, vasopressor drug requirements, blood gases, AVP serum concentrations within 24 hrs after admission, multiple organ dysfunction score, and outcome were recorded. Twenty-four hours after admission, study patients had significantly higher AVP concentrations (11.9 +/- 20.6 pg/mL) than healthy controls (0.92 +/- 0.38 pg/mL; p < .001). Males had lower AVP concentrations than females (9.7 +/- 19.5 vs. 15.1 +/- 20.6 pg/mL; p = .014). Patients with hemodynamic dysfunction had higher AVP concentrations than patients without hemodynamic dysfunction (14.1 +/- 27.1 vs. 8.7 +/- 10.8 pg/mL; p = .042). Patients after cardiac surgery (n = 96) had significantly higher AVP concentrations when compared to patients admitted for other diagnoses (n = 143; p < .001). AVP concentrations were inversely correlated with length of stay in the intensive care unit (correlation coefficient, -0.222; p = .002). There was no correlation between serum AVP concentrations and the incidence of shock or specific hemodynamic parameters. Four (1.7%) of the 239 study patients met criteria for an absolute AVP deficiency (AVP, <0.83 pg/mL), and 32 (13.4%) met criteria for a relative AVP deficiency (AVP, <10 pg/mL, and mean arterial pressure, <70 mm Hg). In shock patients, relative AVP deficiency occurred in 22.2% (septic shock), 15.4% (postcardiotomy shock), and 10% (shock due to a severe systemic inflammatory response syndrome) (p = .316).

CONCLUSIONS

AVP serum concentrations 24 hrs after intensive care unit admission were significantly increased in this mixed critically ill patient population. The lack of a correlation between AVP serum concentrations and hemodynamic parameters suggests complex dysfunction of the vasopressinergic system in critical illness. Relative and absolute AVP deficiency may be infrequent entities during acute surgical critical illness, mostly remaining without significant effects on cardiovascular function.

Pulse High-Volume Hemofiltration in Critically Ill Patients: A New Approach for Patients with Septic Shock

Mortality rates in septic shock remain unacceptably high despite advances in our understanding of the syndrome and its treatment. Humoral factors are increasingly recognized to participate in the pathogenesis of septic shock, giving a biological rationale to therapies that might remove varied and potentially dangerous humoral mediators. While plasma water exchange in the form of hemofiltration can remove circulating cytokines in septic patients, the procedure, as routinely performed, does not have a substantial impact on their plasma levels. More intensive plasma water exchange, as high-volume hemofiltration (HVHF)can reduce levels of these mediators and potentially improve clinical outcomes. However, there are concerns about the feasibility and costs of HVHF as a continuous modality--very high volumes are difficult to maintain over 24 hours and solute kinetics are not optimized by this regimen. We propose pulse HVHF (PHVHF)-HVHF of 85 ml/kg/hr for 6-8 hours followed by continuous venovenous hemofiltration (CVVH) of 35 ml/kg/hr for 16-18 hours-as a new method to combine the advantages of HVHFimprove solute kinetics, and minimize logistic problems. We treated 15 critically ill patients with severe sepsis and septic shock using daily PHVHF in order to evaluate the feasibility of the technique, its effects on hemodynamics, and the impact of the treatment on pathologic apoptosis in sepsis. Hemodynamic improvements were obtained after 6 hours of PHVHF and were maintained subsequently by standard CVVHas demonstrated by the reduction in norepinephrine dose. PHVHFbut not CVVHsignificantly reduces apoptotic plasma activity within 1 hour and the pattern was maintained in the following hours. PHVHF appears to be a feasible modality that may provide the same or greater benefits as HVHFwhile reducing the workload and cost.

Arginine vasopressin in 316 patients with advanced vasodilatory shock

OBJECTIVE

To assess the effects of arginine vasopressin (AVP) on hemodynamic, clinical, and laboratory variables and to determine its adverse side effects in advanced vasodilatory shock.

DESIGN

Retrospective study.

PATIENTS

A total of 316 patients.

INTERVENTIONS

AVP infusion (4 units/hr).

MEASUREMENTS AND MAIN RESULTS

Cardiocirculatory, laboratory, and clinical variables were evaluated before, 0.5, 1, 4, 12, 24, 48, and 72 hrs after administration of AVP. AVP increased mean arterial pressure, systemic vascular resistance, and stroke volume index. Heart rate, central venous pressure, mean pulmonary arterial pressure, norepinephrine, milrinone, and epinephrine requirements decreased. There was no difference in the hemodynamic response between patients with septic shock, postcardiotomy shock, or systemic inflammatory response syndrome. Cardiac index decreased in 41.1% of patients during AVP treatment. In patients with hyperdynamic circulation before AVP, cardiac index decreased, whereas it remained uncharged or tended to increase in patients with normodynamic or hypodynamic circulation. During the course of AVP treatment, liver enzymes (28.5% of patients) and total bilirubin concentrations (69.3% of patients) increased, whereas platelet count decreased (73.4% of patients). Simultaneous hemofiltration significantly contributed to the decrease in platelet count (p < .001) and increase in bilirubin (p < .001). Whereas patients with an increase in bilirubin were more likely to die, a decrease in cardiac index or platelet count and an increase in liver enzymes did not affect mortality. Systemic inflammatory response syndrome as admission diagnosis, a high degree of multiple organ dysfunction, and norepinephrine requirements of >0.5 microg x kg x min before AVP treatment were independent risk factors for death from advanced vasodilatory shock treated with AVP. If norepinephrine dosages exceeded 0.6 microg x kg x min before AVP treatment, a substantial increase in mortality occurred.

CONCLUSIONS

Supplementary AVP infusion improved cardiocirculatory function in advanced vasodilatory shock, but an increase in liver enzymes and bilirubin, and a decrease in platelet count occurred during AVP therapy, particularly during simultaneous hemofiltration. Initiation of AVP infusion before norepinephrine requirements exceeding 0.6 microg x kg x min may improve outcome.

New insights into the protein C pathway: potential implications for the biological activities of drotrecogin alfa (activated)

It has been hypothesized that the protein C pathway is a pivotal link between the inflammation and coagulation cascades. The demonstration that a survival benefit is associated with administration of drotrecogin alfa (activated) (recombinant human activated protein C [APC]) in severe sepsis patients has provided new insights into the protein C pathway. APC was originally identified based on its antithrombotic properties, which result from the inhibition of activated Factors V and VIII. In the early 1990s, any potential anti-inflammatory properties of APC were thought to relate primarily to its inhibition of thrombin generation. However, the mid-1990s saw the identification of the endothelial protein C receptor (EPCR), which has subsequently been shown to be neither endothelial specific nor protein C specific, but has a primary function as a cofactor for enhancing the generation of APC or behaving as an APC receptor. Thus, the potential biologic activities of APC can be classed into two categories related either to the limiting of thrombin generation or to cellular effects initiated by binding to the EPCR. Intracellular signaling initiated by binding of APC to its receptor appears to be mediated by interaction with an adjacent protease-activated receptor (PAR), or by indirect activation of the sphingosine 1-phosphate pathway. Based mostly on in vitro studies, binding of APC to its receptor on endothelial cells leads to a decrease in thrombin-induced endothelial permeability injury, while such binding on blood cells, epithelial cells, and neurons has been shown to inhibit chemotaxis, be anti-apoptotic, and be neuroprotective, respectively. In the Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study, drotrecogin alfa (activated) was associated with improved cardiovascular function, respiratory function, and a prevention of hematologic dysfunction. This article discusses the way in which the interactions of APC may alter the microcirculation.

Clinical manifestations of disordered microcirculatory perfusion in severe sepsis

Microcirculatory dysfunction plays a pivotal role in the development of the clinical manifestations of severe sepsis. Prior to the advent of new imaging technologies, clinicians had been limited in their ability to assess the microcirculation at the bedside. Clinical evidence of microcirculatory perfusion has historically been limited to physical examination findings or surrogates that could be derived from global parameters of oxygen transport. This review explores: (1) the clinical manifestations of severe sepsis that can be linked to microcirculatory dysfunction; (2) the relationship between conventional hemodynamic parameters and microcirculatory blood flow indices; (3) the incorporation of microcirculatory function into the definition of 'shock' in the sepsis syndrome; (4) the role of the microcirculation in oxygen transport; and (5) the potential impact of novel sepsis therapies on microcirculatory flow. Although the study of the microcirculation has long been the domain of basic science, newly developed imaging technologies, such as orthogonal polarization spectral imaging, have now given us the ability to directly visualize and analyze microcirculatory blood flow at the bedside, and see the microcirculatory response to therapeutic interventions. Disordered microcirculatory flow can now be associated with systemic inflammation, acute organ dysfunction, and increased mortality. Using new technologies to directly image microcirculatory blood flow will help define the role of microcirculatory dysfunction in oxygen transport and circulatory support in severe sepsis.

Management of septic shock with a norepinephrine-based haemodynamic algorithm

Management of septic shock (SS) with a norepinephrine (noradrenaline)-based haemodynamic algorithm.

INTRODUCTION

The choice of the best vasopressor for haemodynamic management of septic shock is controversial. Nevertheless, very few studies have been focused on evaluating different management algorithms. The aim of this study was to evaluate the performance of a norepinephrine (NE)-based management protocol. Experience with NE as the initial vasopressor, even if not comparative, could bring relevant data for planning future trails. We also wanted to evaluate the compliance of critical care physicians and nurses with haemodynamic management protocol.

PATIENTS AND METHOD

A norepinephrine-based algorithm for the management of septic shock that commands different sequential interventions according to its requirements, was applied prospectively to 100 consecutive septic shock patients.

RESULTS

Norepinephrine was used as the first vasoactive drug in all patients with a maximum dose of 0.31+/-0.3 microg kg(-1)min(-1) and an ICU mortality of 33%. Physicians applied correctly all the steps of the algorithm in 92% of the patients. Applying the algorithm, avoided the use of pulmonary artery catheter in 31 patients and led to use of lower doses of vasoactive agents than in many other clinical experiences.

CONCLUSION

In conclusion, our data support extended use of an algorithm based on norepinephrine for treating septic shock patients. This is the first clinical study that uses NE as the initial vasopressor drug systematically, and although not comparative, the mortality rates adjusted to APACHE II, are comparable to other studies. It also gives support for future clinical trials comparing norepinephrine with dopamine in this setting.

Hemodynamic variables related to outcome in septic shock

OBJECTIVE

To assess the impact of hemodynamic variables on the outcome of critically ill patients in septic shock and to identify the optimal threshold values related to outcome with special reference to continuously monitored mean arterial pressure (MAP) and mixed venous oxygen saturation (SvO2).

DESIGN AND SETTING

Retrospective cohort study in a university hospital intensive care unit (ICU).

PATIENTS

All consecutive 111 patients with septic shock treated in our ICU between 1 Jan. 1999 and 30 Jan. 2002.

MEASUREMENTS AND RESULTS

The data on the hemodynamic and respiratory monitoring and circulation-related laboratory tests over the first 48 h of treatment in the ICU were collected from the clinical data management system. Data from 6 h and 48 h were analyzed separately. The 30-day mortality rate was 33% (36 of 111). Univariate analysis and forward stepwise logistic regression analysis were performed using the 30-day mortality as the primary endpoint. Mean MAP and lactate on arrival during 6 h, while mean MAP, the area of SvO2 under 70%, and mean CVP during 48 h were independently associated with mortality. MAP level of 65 mmHg and SvO2 of 70% had the highest areas under receiver characteristics curves.

CONCLUSIONS

MAP, SvO2, CVP, and initial lactate were independently associated with mortality in septic shock, with threshold values supporting those published in recent guidelines.

Inducible nitric oxide synthase inhibition improves intestinal microcirculatory oxygenation and CO2 balance during endotoxemia in pigs

OBJECTIVE

We examined whether selective inhibition of inducible nitric oxide synthase (iNOS) promotes intestinal microvascular oxygenation (microPO2) and CO2 off-load after endotoxic shock.

DESIGN AND SETTING

Prospective, controlled experimental study in a university animal research laboratory.

SUBJECTS

13 domestic pigs.

INTERVENTIONS

After baseline measurements shock was induced by 1 microg kg-1 h-1 endotoxin until mean arterial pressure fell below 60 mmHg. After 30 min in shock the animals were resuscitated with either fluid alone (control, n=6) or fluid and the iNOS inhibitor N-[3-(aminomethyl)benzyl]acetamidine hydrochloride (1400W, n=7). As final experimental intervention all animals received the nonselective NOS inhibitor L-NAME.

MEASUREMENTS AND RESULTS

Systemic and regional hemodynamic and oxygenation parameters were measured at baseline, during endotoxemia and shock, hourly for 3 h of 1400W therapy, and 30 min after the final L-NAME administration. microPO2 was assessed by the Pd-porphyrin phosphorescence technique, and the arterial to intestinal PCO2 gap was determined by air tonometry. Endotoxemia and shock resulted in a decrease in ileal mucosal and serosal microPO2 and a rise in PCO2 gap. The combination of 1400W and fluid resuscitation, but not fluid alone, normalized both the serosal microPO2 and the intestinal PCO2 gap. Administration of L-NAME decreased cardiac output and oxygen delivery and intestinal microPO2 and blood flow in both groups.

CONCLUSIONS

Partial blockade of NO production by 1400W increased serosal microvascular oxygenation and decreased the intestinal CO2 gap. This findings are consistent with the idea that 1400W corrects pathological flow distribution and regional dysoxia within the intestinal wall following endotoxic shock.

An exaggerated inflammatory response after CLP correlates with a negative outcome

BACKGROUND

Sepsis is the leading cause of morbidity and mortality in the surgical intensive care unit. We postulate that the variable clinical profile of septic patients is the product of multiple factors, including initiating insult, environment, and genetic make-up. This hypothesis was tested by changing the severity of the insult and the genetic background in an experimental murine model of sepsis.

MATERIALS AND METHODS

Eight-week-old, male A/J and C57BL/6J (B6) mice underwent cecal ligation and puncture (CLP). The cecum was ligated just below the ileocecal valve (>1-cm ligation) or 1 cm from the end of the cecum (1-cm ligation) and single punctured using a 16- or 25-gauge needle (CLP16 or CLP25) or double punctured with a 25-gauge needle (CLP25 x 2). Cytokines were measured in plasma samples by ELISA at different time points after CLP.

RESULTS

Elevated TNF-alpha and IL-6 plasma levels were observed in A/J as compared to B6 mice at 10 and 20 h after CLP16 (1-cm ligation). In contrast, IL-10 levels were decreased in A/J versus B6 mice at 6 h but increased at 10 h. After CLP25 and CLP25 x 2 (1-cm ligation), TNF-alpha was significantly increased at 10 h, but there was no difference in IL-10 and IL-6. CLP with >1-cm ligation resulted in increased cytokine expression after CLP25, CLP25 x 2, and CLP16 versus 1-cm ligation. Mortality after CLP16 was significantly higher in B6 mice with >1-cm versus 1-cm ligation. A/J mortality did not differ between the two procedures.

CONCLUSION

Mortality rate and cytokine profiles after CLP vary depending on the insult severity and the genetic make-up.

Increasing mean arterial pressure in patients with septic shock: effects on oxygen variables and renal function

OBJECTIVE

To measure the effects of increasing mean arterial pressure on oxygen variables and renal function in septic shock.

DESIGN

Prospective, open-label, randomized, controlled study.

SETTING

Medical-surgical intensive care unit of a tertiary care teaching hospital.

PATIENTS

Twenty-eight patients with a diagnosis of septic shock who required fluid resuscitation and pressor agents to increase and maintain mean arterial pressure > or =60 mm Hg.

INTERVENTIONS

Patients were treated with fluid and norepinephrine to achieve and maintain a mean arterial pressure of 65 mm Hg. Then they were randomized in two groups: In the first group (control group, n = 14), mean arterial pressure was maintained at 65 mm Hg, and in the second group (n = 14), mean arterial pressure was increased to 85 mm Hg by increasing the dose of norepinephrine.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic variables (mean arterial pressure, heart rate, mean pulmonary artery pressure, pulmonary artery occlusion pressure, cardiac index, systemic vascular resistance index, pulmonary vascular resistance index, left and right ventricular stroke indexes), metabolic variables (oxygen delivery, oxygen consumption-calorimetric method, arterial lactate), and renal function variables (urine flow, serum creatinine, creatinine clearance) were measured. After introduction of norepinephrine, similar values of hemodynamic, metabolic, and renal function variables were obtained in both groups. No changes were observed in group 1 during the study period. Increasing mean arterial pressure from 65 to 85 mm Hg with norepinephrine in group 2 resulted in a significant increase in cardiac index from 4.8 (3.8-6.0) to 5.8 (4.3-6.9) L.min.m. Arterial lactate and oxygen consumption did not change. No changes were observed in renal function variables: urine flow, 63 (14-127) and 70 (15-121) mL; serum creatinine, 170 (117-333) and 153 (112-310) mumol.L; and creatinine clearance, 50 (12-77) and 67 (13-89) mL.min.1.73 m.

CONCLUSIONS

Increasing mean arterial pressure from 65 to 85 mm Hg with norepinephrine neither affects metabolic variables nor improves renal function.

Pulse high-volume haemofiltration for treatment of severe sepsis: effects on hemodynamics and survival

Introduction

Severe sepsis is the leading cause of mortality in critically ill patients. Abnormal concentrations of inflammatory mediators appear to be involved in the pathogenesis of sepsis. Based on the humoral theory of sepsis, a potential therapeutic approach involves high-volume haemofiltration (HVHF), which has exhibited beneficial effects in severe sepsis, improving haemodynamics and unselectively removing proinflammatory and anti-inflammatory mediators. However, concerns have been expressed about the feasibility and costs of continuous HVHF. Here we evaluate a new modality, namely pulse HVHF (PHVHF; 24-hour schedule: HVHF 85 ml/kg per hour for 6–8 hours followed by continuous venovenous haemofiltration 35 ml/kg per hour for 16–18 hours).

Method

Fifteen critically ill patients (seven male; mean Acute Physiology and Chronic Health Evaluation [APACHE] II score 31.2, mean Simplified Acute Physiology Score [SAPS] II 62, and mean Sequential Organ Failure Assessment 14.2) with severe sepsis underwent daily PHVHF. We measured changes in haemodynamic variables and evaluated the dose of noradrenaline required to maintain mean arterial pressure above 70 mmHg during and after pulse therapy at 6 and 12 hours. PHVHF was performed with 250 ml/min blood flow rate. The bicarbonate-based replacement fluid was used at a 1:1 ratio in simultaneous pre-dilution and post-dilution.

Results

No treatment was prematurely discontinued. Haemodynamics were improved by PHVHF, allowing a significant reduction in noradrenaline dose during and at the end of the PHVHF session; this reduction was maintained at 6 and 12 hours after pulse treatment (P = 0.001). There was also an improvement in systolic blood pressure (P = 0.04). There were no changes in temperature, cardiac index, oxygenation, arterial pH or urine output during the period of observation. The mean daily Kt/V was 1.92. Predicted mortality rates were 72% (based on APACHE II score) and 68% (based on SAPS II score), and the observed 28-day mortality was 47%.

Conclusion

PHVHF is a feasible modality and improves haemodynamics both during and after therapy. It may be a beneficial adjuvant treatment for severe sepsis/septic shock in terms of patient survival, and it represents a compromise between continuous renal replacement therapy and HVHF.

The Use of Common Continuous Monitoring Parameters

Sepsis is a common source of morbidity and mortality among critically ill patients, and targeting measures to promote early recognition and treatment of sepsis is at the forefront of many critical care initiatives. Starting formally in 1992, with the publication of the definitions of sepsis, continuous monitoring of several common physiologic parameters, including electrocardiogram, blood pressure, and oxygen saturation, have been advocated as important in the early identification and treatment of patients with sepsis. The descriptive study detailed in this article was conducted to assess the perceptions and clinical continuous physiologic monitoring practices of experienced critical care clinicians with regard to their use of common physiologic monitoring parameters in the care of patients with sepsis. A convenience sample of 100 physicians and 517 nurses completed a 20-item survey assessing perceptions and clinical monitoring practices related to the care of patients with sepsis. Results indicated that the basic parameters of electrocardiogram, invasive blood pressure, pulmonary arterial catheter monitoring, and oxygen saturation all have value in the recognition and treatment of patients with sepsis. The majority of clinicians used these parameters routinely and felt they were necessary for patient care. These results indicate that clinical practice is in concordance with current practice recommendations.

Adjunctive homeopathic treatment in patients with severe sepsis: a randomized, double-blind, placebo-controlled trial in an intensive care unit

BACKGROUND

Mortality in patients with severe sepsis remains high despite the development of several therapeutic strategies. The aim of this randomized, double-blind, placebo-controlled trial was to evaluate whether homeopathy is able to influence long-term outcome in critically ill patients suffering from severe sepsis.

METHODS

Seventy patients with severe sepsis received homeopathic treatment (n = 35) or placebo (n = 35). Five globules in a potency of 200c were given at 12h interval during the stay at the intensive care unit. Survival after a 30 and 180 days was recorded.

RESULTS

Three patients (2 homeopathy, 1 placebo) were excluded from the analyses because of incomplete data. All these patients survived. Baseline characteristics including age, sex, BMI, prior conditions, APACHE II score, signs of sepsis, number of organ failures, need for mechanical ventilation, need for vasopressors or veno-venous hemofiltration, and laboratory parameters were not significantly different between groups. On day 30, there was non-statistically significantly trend of survival in favour of homeopathy (verum 81.8%, placebo 67.7%, P= 0.19). On day 180, survival was statistically significantly higher with verum homeopathy (75.8% vs 50.0%, P = 0.043). No adverse effects were observed.

CONCLUSIONS

Our data suggest that homeopathic treatment may be a useful additional therapeutic measure with a long-term benefit for severely septic patients admitted to the intensive care unit. A constraint to wider application of this method is the limited number of trained homeopaths.

Norepinephrine and metaraminol in septic shock: a comparison of the hemodynamic effects

OBJECTIVE

To compare the effects of norepinephrine and metaraminol on hemodynamics in septic shock patients.

DESIGN AND SETTING

Open-label, controlled clinical trial in the general intensive care unit of a university-affiliated hospital.

PATIENTS AND PARTICIPANTS

Ten consecutive septic shock patients receiving norepinephrine to maintain the mean arterial pressure higher than 65 mmHg.

INTERVENTIONS

Patients were monitored with pulmonary artery catheter and indirect calorimetry. At the baseline hemodynamic variables were obtained during norepinephrine infusion. Subsequently norepinephrine was replaced by metaraminol infusion in a dose sufficient to keep mean arterial pressure constant. After 20 min of stable arterial pressure a new set of measurement was repeated.

MEASUREMENTS AND RESULTS

Mean arterial pressure did not differ significantly with norepinephrine or metaraminol; there was no relationship between the norepinephrine and metaraminol doses. Replacement norepinephrine with metaraminol did not modify hemodynamic variables; in particular there were no changes in heart rate, stroke volume index, pulmonary artery occlusion pressure, or oxygen consumption index.

CONCLUSIONS

This study shows that metaraminol increases arterial pressure as does norepinephrine in septic shock patients. Despite similar effects of norepinephrine and metaraminol, there was no relationship between the dose of the two drugs.

Progress in Postoperative ICU Management

The clinical case presented in this article illustrates how many of the more recent advances in the management of critically ill patients apply to current clinical practice. Simple cost-effective general measures (eg, optimal sterile precautions during procedures; hand washing; early goal-directed resuscitation with appropriate fluids, inotropes, and antibiotics; and surgical source control of infected foci) still should form the basis of clinical practice, however. There has been renewed interest in blood transfusion therapy and its associated risks. Lower tidal volume ventilation now is practiced almost universally in patients with ARDS, and several new selective pulmonary vasodilators have extended the armamentarium when taking care of these patients. High-frequency oscillatory ventilation and ECMO remain challenging options in patients with refractory hypoxemia. Appropriate patient selection is important when corticosteroid therapy is considered. Tight blood glucose control and monitoring improve outcome and should be part of ICU care of septic patients. The role of the PAC is controversial. Other techniques to measure cardiac output, hemodynamics, and perfusion are available and should be considered. Sedation and analgesia form an integral part of critical care. Because of its immediate and long-term risks, neuromuscular blockade should be used sparingly and only when all other options have been exhausted. Ongoing education regarding sedation protocols and the effect of sedation on outcome is needed among physicians and nurses caring for these patients.

Management of severe sepsis and septic shock

PURPOSE OF REVIEW

Severe sepsis and septic shock are common and deadly conditions for which the epidemiology, pathogenesis, and management continue to evolve. Recent publications (2003 and early 2004) have been systematically reviewed for important new original research and scholarly reviews, with an emphasis on clinical advances in adults.

RECENT FINDINGS

Important new epidemiologic studies establish the increasing frequency (nearly 9% per year) and falling mortality rates associated with sepsis. Sepsis definitions were reviewed by a group of experts, and the principal features of the 1991 consensus conference definitions were supported, with a new framework for evaluation of sepsis proposed. New research and thoughtful reviews continue to elucidate the pathogenesis of sepsis, with emphasis on innate immunity and time-based changes in immune status, varying from hyperreactive immunity and inflammation to immune depression with enhanced risk for nosocomial infections. A comprehensive evidence-based approach to the management of severe sepsis is presented in an important document developed by representatives from many critical care and infectious disease societies. Management includes early targeted resuscitation, broad empiric antibiotic coverage and source control, effective shock evaluation and treatment, adjuvant therapy with recombinant human activated protein C and moderate-dose hydrocortisone in selected patients, and comprehensive supportive care. Recently published multicenter clinical trials for novel agents have been disappointing, particularly for a nitric oxide synthase inhibitor that effectively supported blood pressure but increased mortality.

SUMMARY

The works reviewed reflect the advances in the care of patients with sepsis.

Methods of monitoring shock

Intensive monitoring is a crucial component of the management of shock. However, there is little consensus about optimal strategies for monitoring. Although the pulmonary artery catheter has been widely used, conflicting data exist about the utility of this device. A variety of other techniques have been developed in hopes of providing clinically useful information about myocardial function, intravascular volume, and indices of organ function. In addition, there is evolving evidence that targeting and monitoring certain physiological goals may be most important early in the course of shock. In this chapter, we examine many of the available monitoring techniques and the evidence supporting their use.