Mechanical ventilation in sepsis-induced acute lung injury/acute respiratory distress syndrome: an evidence-based review

Effects of vagus nerve stimulation and vagotomy on systemic and pulmonary inflammation in a two-hit model in rats

Pulmonary inflammation contributes to ventilator-induced lung injury. Sepsis-induced pulmonary inflammation (first hit) may be potentiated by mechanical ventilation (MV, second hit). Electrical stimulation of the vagus nerve has been shown to attenuate inflammation in various animal models through the cholinergic anti-inflammatory pathway. We determined the effects of vagotomy (VGX) and vagus nerve stimulation (VNS) on systemic and pulmonary inflammation in a two-hit model. Male Sprague-Dawley rats were i.v. administered lipopolysaccharide (LPS) and subsequently underwent VGX, VNS or a sham operation. 1 hour following LPS, MV with low (8 mL/kg) or moderate (15 mL/kg) tidal volumes was initiated, or animals were left breathing spontaneously (SP). After 4 hours of MV or SP, rats were sacrificed. Cytokine and blood gas analysis was performed. MV with 15, but not 8 mL/kg, potentiated the LPS-induced pulmonary pro-inflammatory cytokine response (TNF-α, IL-6, KC: p<0.05 compared to LPS-SP), but did not affect systemic inflammation or impair oxygenation. VGX enhanced the LPS-induced pulmonary, but not systemic pro-inflammatory cytokine response in spontaneously breathing, but not in MV animals (TNF-α, IL-6, KC: p<0.05 compared to SHAM), and resulted in decreased pO(2) (p<0.05 compared to sham-operated animals). VNS did not affect any of the studied parameters in both SP and MV animals. In conclusion, MV with moderate tidal volumes potentiates the pulmonary inflammatory response elicited by systemic LPS administration. No beneficial effects of vagus nerve stimulation performed following LPS administration were found. These results questions the clinical applicability of stimulation of the cholinergic anti-inflammatory pathway in systemically inflamed patients admitted to the ICU where MV is initiated.

Surgical prophylaxis and other complication avoidance care bundles

Individual health care quality measures that have been shown to improve outcome can be combined together into what are called care bundles, with the expectation that this set of practices produces further improvements in outcome. Prevention of surgical site infection is the focus of several quality measures put forward by the Surgical Care Improvement Project; these can collectively be considered a bundle as well. Whether these process measures, which include several components related to the administration of antibiotic prophylaxis, are effective in decreasing rates of surgical site infection has come under considerable debate recently.

A newly synthetic vitamin E derivative, E-Ant-S-GS, attenuates lung injury caused by cecal ligation and puncture-induced sepsis in rats

BACKGROUND

Cytokine activation and the ensuing spread of damage to distant organs play a central role in sepsis caused by generalized peritonitis, which accompanies surgical conditions such as gastrointestinal perforation. Anti-inflammatory properties have been discovered in endogenous substances such as vitamin E; we evaluated, in a rat model of peritonitis-induced sepsis, the newly synthetic vitamin E derivative E-Ant-S-GS, in which the endogenous substances vitamin E, glutathione, 5-OH-anthranilic acid, and succinic acid are chemically linked.

METHODS

We used a model of sepsis in male Wistar rats with the cecal ligation and puncture (CLP) method. To evaluate the anti-inflammatory effects of E-Ant-S-GS, we measured serum interleukin-6 (IL-6) levels at various times after CLP. To assess the effects of E-Ant-S-GS in acute lung injury, we evaluated histologically lung tissue 12 hours after CLP by hematoxylin-eosin staining. In addition, myeloperoxidase (MPO) activity and expression of protease-activated receptor 1 (PAR1) and high mobility group box 1 (HMGB1) in the lung were determined.

RESULTS

Serum IL-6 levels increased progressively after the CLP procedure; this cytokine induction was attenuated by E-Ant-S-GS. Increased MPO activity in lung tissue and marked changes in lung histology caused by CLP-induced sepsis were also ameliorated by E-Ant-S-GS. In addition, E-Ant-S-GS suppressed the upregulation of PAR1 and HMGB1 in the lungs after CLP.

CONCLUSION

The newly synthetic vitamin E derivative E-Ant-S-GS showed anti-inflammatory actions and organ-protective effects in a rat model of sepsis, suggesting its potential clinical use as a therapeutic agent against systemic inflammation.

Pragmatic management of Panton-Valentine leukocidin-associated staphylococcal diseases

Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus is associated with a broad spectrum of diseases, ranging from common uncomplicated soft tissue infections to severe diseases such as complicated soft tissue infections, extensive bone and joint infections, and necrotising pneumonia. Specialised management of infection based on the presence of PVL may not be required for mild infections, whereas it could be lifesaving in other settings. Moreover, most severe PVL diseases are recently identified entities and a 'gold standard' treatment from comparatives studies of different therapeutic options is lacking. Thus, recommendations are based on expert opinions, which are elaborated based on theory, in vitro data and analogies with other toxin-mediated diseases. In this review, we consider the potential need for specialised PVL-based management and, if required, which tools should be used to achieve optimal management.

Rescue therapy in adult and pediatric patients with pH1N1 influenza infection: a tertiary center intensive care unit experience from April to October 2009

OBJECTIVE

Severe respiratory failure is a well-recognized complication of pH1N1 influenza infection. Limited data regarding the efficacy of rescue therapies, including high-frequency oscillatory ventilation and extracorporeal membrane oxygenation, have been previously reported in the setting of pH1N1 influenza infection in the United States.

DESIGN

Retrospective, single-center cohort study.

SETTING

Pediatric, cardiac, surgical, and medical intensive care units in a single tertiary care center in the United States.

PATIENTS

One hundred twenty-seven consecutive patients with confirmed influenza A infection requiring hospitalization between April 1, 2009, and October 31, 2009.

INTERVENTIONS

Electronic medical records were reviewed for demographic and clinical data.

MEASUREMENTS AND MAIN RESULTS

The number of intensive care unit admissions appears inversely related to age with 39% of these admissions <20 yrs of age. Median duration of intensive care unit care was 10.0 days (4.0-24.0), and median duration of mechanical ventilation was 8.0 days (0.0-23.5). Rescue therapy (high-frequency oscillatory ventilation or extracorporeal membrane oxygenation) was used in 36% (12 of 33) of intensive care unit patients. The severity of respiratory impairment was determined by Pao²/Fio² ratio and oxygenation index. High-frequency oscillatory ventilation at 24 hrs resulted in improvements in median Pao²/Fio² ratio (71 [58-93] vs. 145 [126-185]; p < .001), oxygenation index (27 [20-30] vs. 18 [12-25]; p = .016), and Fio2 (100 [70-100] vs. 45 [40-55]; p < .001). Extracorporeal membrane oxygenation resulted in anticipated improvement in parameters of oxygenation at both 2 hrs and 24 hrs after initiation of therapy. Despite the severity of oxygenation impairment, overall survival for both rescue therapies was 75% (nine of 12), 80% (four of five) for high-frequency oscillatory ventilation alone, and 71% (five of seven) for high-frequency oscillatory ventilation + extracorporeal membrane oxygenation.

CONCLUSION

In critically ill adult and pediatric patients with pH1N1 infection and severe lung injury, the use of high-frequency oscillatory ventilation and extracorporeal membrane oxygenation can result in significant improvements in Pao²/Fio² ratio, oxygenation index, and Fio². However, the impact on mortality is less certain.

Acute lung injury in children: therapeutic practice and feasibility of international clinical trials

OBJECTIVES

To describe mechanical ventilation strategies in acute lung injury and to estimate the number of eligible patients for clinical trials on mechanical ventilation management. In contrast to adult medicine, there are few clinical trials to guide mechanical ventilation management in children with acute lung injury.

DESIGN

A cross-sectional study for six 24-hr periods from June to November 2007.

SETTING

Fifty-nine pediatric intensive care units in 12 countries in North America and Europe.

PATIENTS

We identified children meeting acute lung injury criteria and collected detailed information on illness severity, mechanical ventilatory support, and use of adjunctive therapies.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 3823 patients screened, 414 (10.8%) were diagnosed with acute lung injury by their treating physician, but only 165 (4.3%) patients met prestablished inclusion/exclusion criteria to this trial and, therefore, would have been eligible for a clinical trial. Of these, 124 (75.2%) received conventional mechanical ventilation, 27 (16.4%) received high-frequency oscillatory ventilation, and 14 (8.5%) received noninvasive mechanical ventilation. In the conventional mechanical ventilation group, 43.5% were ventilated in a pressure control mode with a mean tidal volume of 8.3 ± 3.3 mL/kg; and there was no clear relationship between positive end-expiratory pressure and Fio2 delivery in the conventional mechanical ventilation group. Use of adjunctive treatments, including nitric oxide, prone positioning, surfactant, hemofiltration, recruitment maneuvers, steroids, bronchodilators, and fluid restriction, was highly variable.

CONCLUSIONS

Our study reveals inconsistent mechanical ventilation practice and use of adjunctive therapies in children with acute lung injury. Pediatric clinical trials assessing mechanical ventilation management are needed to generate evidence to optimize outcomes. We estimate that a large number of centers (∼60) are needed to conduct such trials; it is imperative, therefore, to bring about international collaboration.

Clinical application of ventilator modes: Ventilatory strategies for lung protection

INTRODUCTION

Identification of the mortality reducing effect of lung protective ventilation using low tidal volumes and pressure limitation is one of the biggest advances in the application of mechanical ventilation. Yet studies continue to demonstrate low adoption of this style of ventilation. Critical care nurses in Australia and New Zealand have a high level of responsibility and autonomy for mechanical ventilation and weaning practices and therefore require in-depth knowledge of ventilator technology, its clinical application and the current evidence for effective ventilation strategies.

AIM

To present an overview of current knowledge and research relating to lung protective ventilation.

METHOD

A multidatabase literature search using the terms protective ventilation, open lung, high frequency oscillatory ventilation, airway pressure release ventilation, and weaning.

RESULTS

Based on clinical trials and physiological evidence lung protective strategies using low tidal volumes and moderate levels of PEEP have been recommended as strategies to prevent tidal alveolar collapse and overdistension in patients with ALI/ARDS. Evidence now suggests these strategies may also be beneficial in patients with normal lungs. Lung protective ventilation may be applied with either volume or pressure-controlled ventilation. Pressure-controlled ventilation allows regulation over injurious peak inspiratory pressures; however no study has identified the superiority of pressure-controlled ventilation over low tidal volume strategies using volume-control. Other lung protective ventilation strategies include moderate to high positive-end expiratory pressure, recruitment manoeuvres, high frequency oscillatory ventilation, and airway pressure release ventilation though definitive trials identifying consistently improved patient outcomes are still needed. No ventilation strategy can be more lung protective than the timely discontinuation of mechanical ventilation. Despite the above recommendations, evidence suggests the decision to commence weaning and attempt extubation continue to be delayed. Critical care nurses play a vital role in the recognition of patients capable of spontaneous breathing and ready for extubation. Organisational interventions such as weaning protocols as well as computerised weaning systems may have less effect when nurses are able to manage weaning processes effectively.

CONCLUSIONS

Lung protective ventilatory strategies are not consistently applied and weaning and extubation continue to be delayed. Critical care nurses need to establish a strong knowledge base to promote effective and appropriate management of patients requiring mechanical ventilation.

Clinical meaning of early oxygenation improvement in severe acute respiratory distress syndrome under prolonged prone positioning

BACKGROUND/AIMS

Ventilating patients with acute respiratory distress syndrome (ARDS) in the prone position has been shown to improve arterial oxygenation, but prolonged prone positioning frequently requires continuous deep sedation, which may be harmful to patients. We evaluated the meaning of early gas exchange in patients with severe ARDS under prolonged (> or = 12 hours) prone positioning.

METHODS

We retrospectively studied 96 patients (mean age, 60.1 +/- 15.6 years; 75% men) with severe ARDS (PaO(2)/FiO2 < or = 150 mmHg) admitted to a medical intensive care unit (MICU). The terms "PaO2 response" and "PaCO2 response" represented responses that resulted in increases in the PaO2/FiO2 ratio of > or = 20 mmHg and decreases in PaCO2 of > or = 1 mmHg, respectively, 8 to 12 hours after first placement in the prone position.

RESULTS

The mean duration of prone positioning was 78.5 +/- 61.2 hours, and the 28-day mortality rate after MICU admission was 56.3%. No significant difference in clinical characteristics was observed between PaO2 and PaCO2 responders and non-responders. The PaO2 responders after prone positioning showed an improved 28-day outcome, compared with non-responders by Kaplan-Meier survival estimates (p < 0.05 by the log-rank test), but the PaCO12 responders did not.

CONCLUSIONS

Our results suggest that the early oxygenation improvement after prone positioning might be associated with an improved 28-day outcome and may be an indicator to maintain prolonged prone positioning in patients with severe ARDS.

The role of keratinocyte-derived chemokine in hemorrhage-induced acute lung injury in mice

Dominant inflammatory cytokines might be different depending on the underlying causes of acute lung injury (ALI). The role of kertinocyte-derived chemokine (KC), a potent chemoattractant for neutrophils, has not been clearly established in hemorrhage-induced ALI. In this study, lung injury and cytokine expression were evaluated in LPS- or hemorrhage-induced ALI models of BALB/c mice. The myeloperoxidase activities at 4 hr after hemorrhage and LPS-injection were 47.4+/-13.0 and 56.5+/-16.4 U/g, respectively. NF-kappaB activity peaked at 4 hr after hemorrhage, which was suppressed to the control level by anti-high mobility group B1 (HMGB1) antibody. Lung expressions of TNF-alpha, MIP-2, and IL-1beta were increased by LPS injection. However, there was only a minimal increase in IL-1beta and no expressions of TNF-alpha or MIP-2 in hemorrhage-induced ALI. In contrast, lung KC increased significantly at 4 hr after hemorrhage compared to control levels (83.1+/-12.3 vs. 14.2+/-1.6 pg/mL/mg by ELISA) (P<0.05). By immunohistochemical staining, lung neutrophils stained positive for KC. Increased KC was also observed in bronchoalveolar lavage fluid and plasma. KC plays an important role in hemorrhage-induced ALI.

Mortality in sepsis versus non-sepsis induced acute lung injury

Introduction

Sepsis-induced acute lung injury (ALI) has been reported to have a higher case fatality rate than other causes of ALI. However, differences in the severity of illness in septic vs. non-septic ALI patients might explain this finding.

Methods

520 patients enrolled in the Improving Care of ALI Patients Study (ICAP) were prospectively characterized as having sepsis or non sepsis-induced ALI. Biologically plausible risk factors for in-hospital death were considered in multiple logistic regression models to evaluate the independent association of sepsis vs. non-sepsis ALI risk factors with mortality.

Results

Patients with sepsis-induced ALI had greater illness severity and organ dysfunction (APACHE II and SOFA scores) at ALI diagnosis and higher crude in-hospital mortality rates compared with non-sepsis ALI patients. Patients with sepsis-induced ALI received similar tidal volumes, but higher levels of positive end expiratory pressure, and had a more positive net fluid balance in the first week after ALI diagnosis. In multivariable analysis, the following variables (odds ratio, 95% confidence interval) were significantly associated with hospital mortality: age (1.04, 1.02 to 1.05), admission to a medical intensive care unit (ICU) (2.76, 1.42 to 5.36), ICU length of stay prior to ALI diagnosis (1.15, 1.03 to 1.29), APACHE II (1.05, 1.02 to 1.08), SOFA at ALI diagnosis (1.17, 1.09 to 1.25), Lung Injury Score (2.33, 1.74 to 3.12) and net fluid balance in liters in the first week after ALI diagnosis (1.06, 1.03 to 1.09). Sepsis did not have a significant, independent association with mortality (1.02, 0.59 to 1.76).

Conclusions

Greater severity of illness contributes to the higher case fatality rate observed in sepsis-induced ALI. Sepsis was not independently associated with mortality in our study.

Recruitment manoeuvres for adults with acute lung injury receiving mechanical ventilation

BACKGROUND

Recruitment manoeuvres are often used to treat patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) but the effect of this treatment on clinical outcomes has not been well established.

OBJECTIVES

The objective of this review was to examine recruitment manoeuvres compared to standard care as therapy for adults with acute lung injury in order to quantify the effects on patient outcomes (mortality, length of ventilation, and other relevant outcomes).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 2); MEDLINE (January 1966 to May 2008); EMBASE (January 1980 to May 2008); LILACS (1982 to May 2008); CINAHL (1982 to May 2008); and Current Controlled Trials (www.controlled-trials.com).

SELECTION CRITERIA

We included randomized controlled trials of adults who were mechanically ventilated comparing recruitment manoeuvres to standard care for those patients diagnosed with ALI or ARDS.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Seven trials met the inclusion criteria for this review (the total number of included participants was 1170). All trials included a recruitment manoeuvre as part of the treatment strategy for patients on mechanical ventilation for ARDS or ALI. However, two of the trials included a package of ventilation that was different from the control ventilation in aspects other than the recruitment manoeuvre. The intervention group showed no significant difference on 28-day mortality (RR 0.73, 95% CI 0.46 to 1.17, P = 0.2). Similarly there was no statistical difference for risk of barotrauma (RR 0.50, 95% CI 0.07 to 3.52, P = 0.5) or blood pressure (MD 0.9 mm Hg, 95% CI -4.28 to 6.08, P = 0.73). Recruitment manoeuvres significantly increased oxygenation above baseline levels for a short period of time in four of the five studies that measured oxygenation. There were insufficient data on length of ventilation or hospital stay to pool results.

AUTHORS' CONCLUSIONS

There is not evidence to make conclusions on whether recruitment manoeuvres reduce mortality or length of ventilation in patients with ALI or ARDS.

Permissive hypercapnia

Mechanical ventilation using high tidal volume (VT) and transpulmonary pressure can damage the lung, causing ventilator-induced lung injury. Permissive hypercapnia, a ventilatory strategy for acute respiratory failure in which the lungs are ventilated with a low inspiratory volume and pressure, has been accepted progressively in critical care for adult, pediatric, and neonatal patients requiring mechanical ventilation and is one of the central components of current protective ventilatory strategies.

[Aspiration syndrome: epidemiology, pathophysiology, and therapy]

Aspiration syndromes are important causes of morbidity and mortality during general anaesthesia as well as in the intensive care unit. Up to 30% of patients with aspiration may develop an acute respiratory distress syndrome, with an attributed mortality of 16%. Although aspiration syndrome is not a frequent event, the anaesthesist must be familiar with the management of this complication and must know the risk factors for it. Discrimination between pneumonitis, an abacterial inflammation, and pneumonia is of utmost importance because treatment strategies differ; for instance, treatment is merely supportive in pneumonitis. This review gives an overview of the epidemiology and pathophysiology of aspiration syndrome, strategies to avoid aspiration, and a brief discussion of treatment concepts.

Effects of prone and supine position on oxygenation and inflammatory mediator in a hydrochloric acid-induced lung dysfunction in rats

PURPOSE

To compare the effectiveness of mechanical ventilation of supine versus prone position in hydrochloric acid (HCl)-induced lung dysfunction.

METHODS

Twenty, adult, male, Wistar-EPM-1 rats were anesthetized and randomly grouped (n=5 animals per group) as follows: CS-MV (mechanical ventilation in supine position); CP-MV (mechanical ventilation in prone position); bilateral instillation of HCl and mechanical ventilation in supine position (HCl+S); and bilateral instillation of HCl and mechanical ventilation in prone position (HCl+P). All groups were ventilated for 180 minutes. The blood partial pressures of oxygen and carbon dioxide were measured in the time points 0 (zero; 10 minutes before lung injury for stabilization), and at the end of times acid injury, 60, 120 and 180 minutes of mechanical ventilation. At the end of experiment the animals were euthanized, and bronchoalveolar lavages (BALs) were taken to determine the contents of total proteins, inflammatory mediators, and lungs wet-to-dry ratios.

RESULTS

In the HCl+P group the partial pressure of oxygen increased when compared with HCl+S (128.0+/-2.9 mmHg and 111.0+/-6.7 mmHg, respectively) within 60 minutes. TNF-alpha levels in BAL do not differ significantly in the HCl+P group (516.0+/-5.9 pg/mL), and the HCl+S (513.0+/-10.6 pg/mL).

CONCLUSION

The use of prone position improved oxygenation, but did not reduce TNF-alpha in BAL upon lung dysfunction induced by HCl.

Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC)

Non-thrombotic PE does not represent a distinct clinical syndrome. It may be due to a variety of embolic materials and result in a wide spectrum of clinical presentations, making the diagnosis difficult. With the exception of severe air and fat embolism, the haemodynamic consequences of non-thrombotic emboli are usually mild. Treatment is mostly supportive but may differ according to the type of embolic material and clinical severity.

Pulmonary vs nonpulmonary sepsis and mortality in acute lung injury

BACKGROUND

Acute lung injury (ALI) is a frequent complication of sepsis. It is unclear if a pulmonary vs nonpulmonary source of sepsis affects mortality in patients with sepsis-induced ALI.

METHODS

Two hundred eighty-eight consecutive patients with sepsis-induced ALI from 14 ICUs at four hospitals in Baltimore, MD were prospectively classified as having a pulmonary vs nonpulmonary source of sepsis. Multiple logistic regression was conducted to evaluate the independent association of a pulmonary vs nonpulmonary source of sepsis with inpatient mortality.

RESULTS

In an unadjusted analysis, in-hospital mortality was lower for pulmonary vs nonpulmonary source of sepsis (42% vs 66%, p < 0.0001). Patients with pulmonary sepsis had lower acute physiology and chronic health evaluation (APACHE) II and sequential organ failure assessment (SOFA) scores, shorter ICU stays prior to the development of ALI, and higher lung injury scores. In the adjusted analysis, several factors were predictive of mortality: age (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01 to 1.06), Charlson comorbidity index (OR, 1.15; 95% CI, 1.02 to 1.30), ICU length of stay prior to ALI diagnosis (OR, 1.19; 95% CI, 1.01 to 1.39), APACHE II score (OR, 1.07; 95% CI, 1.03 to 1.12), lung injury score (OR, 1.64; 95% CI, 1.11 to 2.43), SOFA score (OR, 1.15; 95% CI, 1.06 to 1.26), and cumulative fluid balance in the first 7 days after ALI diagnosis (OR, 1.06; 95% CI, 1.03 to 1.10). A pulmonary vs nonpulmonary source of sepsis was not independently associated with mortality (OR, 0.72; 95% CI, 0.38 to 1.35).

CONCLUSIONS

Although lower mortality was observed for ALI patients with a pulmonary vs nonpulmonary source of sepsis, this finding is likely due to a lower severity of illness in those with pulmonary sepsis. Pulmonary vs nonpulmonary source of sepsis was not independently predictive of mortality for patients with ALI.

Procalcitonin assay in systemic inflammation, infection, and sepsis: clinical utility and limitations

OBJECTIVE

The use of procalcitonin (ProCT) as a marker of several clinical conditions, in particular, systemic inflammation, infection, and sepsis, will be clarified, and its current limitations will be delineated. In particular, the need for a more sensitive assay will be emphasized. For these purposes, the medical literature comprising clinical studies pertaining to the measurement of serum ProCT in various clinical settings was examined.

DATA SOURCE AND SELECTION

A PubMed search (1965 through November 2007) was conducted, including manual cross-referencing. Pertinent complete publications were obtained using the MeSH terms procalcitonin, C-reactive protein, sepsis, and biological markers. Textbook chapters were also read and extracted.

DATA EXTRACTION AND SYNTHESIS

Available clinical and other patient data from these sources were reviewed, including any data relating to precipitating factors, clinical findings, associated illnesses, and patient outcome. Published data concerning sensitivity, specificity, and reproducibility of ProCT assays were reviewed.

CONCLUSIONS

Based on available data, the measurement of serum ProCT has definite utility as a marker of severe systemic inflammation, infection, and sepsis. However, publications concerning its diagnostic and prognostic utility are contradictory. In addition, patient characteristics and clinical settings vary markedly, and the data have been difficult to interpret and often extrapolated inappropriately to clinical usage. Furthermore, attempts at meta-analyses are greatly compromised by the divergent circumstances of reported studies and by the sparsity and different timing of the ProCT assays. Although a high ProCT commonly occurs in infection, it is also elevated in some noninfectious conditions. Thus, the test is not a specific indicator of either infection or sepsis. Moreover, in any individual patient, the precipitating cause of an illness, the clinical milieu, and complicating conditions may render tenuous any reliable estimations of severity or prognosis. It also is apparent that even a febrile septic patient with documented bacteremia may not necessarily have a serum ProCT that is elevated above the limit of functional sensitivity of the assay. In this regard, the most commonly applied assay (i.e., LUMItest) is insufficiently sensitive to detect potentially important mild elevations or trends. Clinical studies with a more sensitive ProCT assay that is capable of rapid and practicable day-to-day monitoring are needed and shortly may be available. In addition, investigations showing that ProCT and its related peptides may have mediator relevance point to the need for evaluating therapeutic countermeasures and studying the pathophysiologic effect of hyperprocalcitonemia in serious infection and sepsis.

A 5-year PICU experience of disseminated staphylococcal disease, part 2: management, critical care needs and outcome

Staphylococcus aureus causes an impressive spectrum of disease in tropics and subtropics. Scanty data are available regarding disseminated staphylococcal disease (DSD) in children, especially on their critical care needs. It is important to recognize and prioritize patients who may benefit most from Pediatric Critical Care. The objective of this article is to review the, critical care needs, management and outcome of patients with DSD and to identify clinical indicators for need of critical care. The study setting is a Pediatric Intensive Care Unit of an urban tertiary care teaching hospital in a developing economy. Fifty-three patients (age, 1 month to 12 years) with DSD, admitted to PICU during June 1994 to June 1999, form the subjects for the study. DSD was defined as involvement of at least two distant organs with presence of Gram-positive cocci in clusters and/or growth of S. aureus from at least one normally sterile body fluid. Data regarding demographic and clinical picture, microbiological profile, indication for PICU admission, monitoring needs, medical and surgical management and outcome was retrieved from the case records. Critical care problems included septic shock (28/53), pericardial effusion (21/53, cardiac tamponade in six), raised intracranial pressure (5 patients) and refractory status epilepticus (1 patient). The majority developed septic shock after first few doses of parenteral antimicrobials. They required an impressive amount of fluid [100 (56) ml/kg] during initial 6 h of resuscitation, and 90% had myocardial dysfunction requiring inotropic support. Tracheal intubation was needed in 18 (34%) and ventilatory support in 17 (32%) patients. About 60% patients had metabolic abnormalities. Soft tissue disease was associated with high risk of septic shock (RR, 1.77; P < 0.05). Presence of both septic shock and need for ventilation was associated with high mortality (RR, 20.5; P < 0.001). Patients with suspected DSD need intensive cardio-respiratory monitoring during initial 48-72 h of therapy; and those who develops shock, respiratory failure, pericardial effusion and necrotizing soft tissue disease should be prioritized for PICU admission.

Influence of upper body position on middle cerebral artery blood velocity during continuous positive airway pressure breathing

Continuous positive airway pressure (CPAP) is a treatment modality for pulmonary oxygenation difficulties. CPAP impairs venous return to the heart and, in turn, affects cerebral blood flow (CBF) and augments cerebral blood volume (CBV). We considered that during CPAP, elevation of the upper body would prevent a rise in CBV, while orthostasis would challenge CBF. To determine the body position least affecting indices of CBF and CBV, the middle cerebral artery mean blood velocity (MCA V(mean)) and the near-infrared spectroscopy determined frontal cerebral hemoglobin content (cHbT) were evaluated in 11 healthy subjects during CPAP at different body positions (15 degrees head-down tilt, supine, 15 degrees, 30 degrees and 45 degrees upper body elevation). In the supine position, 10 cmH(2)O of CPAP reduced MCA V(mean) by 9 +/- 3% and increased cHbT by 4 +/- 2 micromol/L (mean +/- SEM); (P < 0.05). In the head-down position, CPAP increased cHbT to 13 +/- 2 micromol/L but left MCA V(mean) unchanged. Upper body elevation by 15 degrees attenuated the CPAP associated reduction in MCA V(mean) (-7 +/- 2%), while cHbT returned to baseline (1 +/- 2 micromol/L). With larger elevation of the upper body MCA V(mean) decreased progressively to -17 +/- 3%, while cHbT remained unchanged from baseline. These results suggest that upper body elevation by approximately 15 degrees during 10 cmH(2)O CPAP prevents an increase in cerebral blood volume with minimal effect on cerebral blood flow.

Prone ventilation in trauma or surgical patients with acute lung injury and adult respiratory distress syndrome: is it beneficial?

BACKGROUND

To compare the effectiveness of supine versus prone kinetic therapy in mechanically ventilated trauma and surgical patients with acute lung injury (ALI) and adult respiratory distress syndrome (ARDS).

METHODS

A retrospective review of all patients with ALI/ARDS who were placed on either a supine (roto-rest) or prone (roto-prone) oscillating bed was performed. Data obtained included age, revised trauma score (RTS), base deficit, Injury Severity Score (ISS), head Abbreviated Injury Scale score (AIS), chest (AIS), PaO2/FiO2 ratio, FiO2 requirement, central venous pressure (CVP), days on the bed, ventilator days, use of pressors, complications, mortality, and pulmonary-associated mortality. Data are expressed as mean+/-SE with significance attributed to p<0.05.

RESULTS

From March 1, 2004 through May 31, 2006, 4,507 trauma patients were admitted and 221 were identified in the trauma registry as having ALI or ARDS. Of these, 53 met inclusion criteria. Additionally, 8 general surgery patients met inclusion criteria. Of these 61 patients, 44 patients were positioned supine, 13 were placed prone, and 4 patients that were initially placed supine were changed to prone positioning. There was no difference between the groups in age, CVP, ISS, RTS, base deficit, head AIS score, chest AIS score, abdominal AIS score, or probability of survival. The PaO2/FiO2 ratios were not different at study entry (149 vs. 153, p=NS), and both groups showed improvement in PaO2/FiO2 ratios. However, the prone group had better PaO2/FiO2 ratios than the supine group by day 5 (243 vs. 200, p=0.066). The prone group had fewer days on the ventilator (13.6 vs. 24.2, p=0.12), and shorter hospital lengths of stay (22 days vs. 40 days, p=0.08). There were four patients who failed to improve with supine kinetic therapy that were changed to prone kinetic therapy. These patients had significant improvements in PaO2/FiO2 ratio, and significantly lower FiO2 requirements. There were 18 deaths (7 pulmonary related) in the supine group and 1 death in the prone group (p < 0.01 by chi test).

CONCLUSIONS

ALI/ARDS patients who received prone kinetic therapy had greater improvement in PaO2/FiO2 ratio, lower mortality, and less pulmonary-related mortality than did supine positioned patients. The use of a prone-oscillating bed appears advantageous for trauma and surgical patients with ALI/ARDS and a prospective, randomized trial is warranted.

Lung protective ventilatory strategies in acute lung injury and acute respiratory distress syndrome: from experimental findings to clinical application

This review addresses the physiological background and the current status of evidence regarding ventilator-induced lung injury and lung protective strategies. Lung protective ventilatory strategies have been shown to reduce mortality from adult respiratory distress syndrome (ARDS). We review the latest knowledge on the progression of lung injury by mechanical ventilation and correlate the findings of experimental work with results from clinical studies. We describe the experimental and clinical evidence of the effect of lung protective ventilatory strategies and open lung strategies on the progression of lung injury and current controversies surrounding these subjects. We describe a rational strategy, the open lung strategy, to accomplish an open lung, which may further prevent injury caused by mechanical ventilation. Finally, the clinician is offered directions on lung protective ventilation in the early phase of ARDS which can be applied on the intensive care unit.

Mechanical ventilation: a tutorial for pharmacists

Mechanical ventilation is an integral part of the critical care environment and requires orchestration by a multidisciplinary team of clinicians to optimize therapeutic outcomes. By tradition, pharmacists have not been included on this team since this therapeutic modality is not considered relevant to their scope of practice. However, pharmacists play a critical role in the management of patients receiving mechanical ventilation by assisting in the development of institutional guidelines and protocols, by maintaining accuracy of prescribed drug dosages, by monitoring for drug-drug and drug-disease interactions, by assisting with alternative drug selections, and by maintaining continued quality assessment of drug administration. Pharmacists able to understand and integrate mechanical ventilation with the pharmacotherapeutic needs of patients are better qualified practitioners. The goal of this article is to help clinical pharmacists better understand the complexities of mechanical ventilation and to apply this information in optimizing delivery of pharmaceutical agents to critical care patients.

Pretreatment with olprinone hydrochloride, a phosphodiesterase III inhibitor, attenuates lipopolysaccharide-induced lung injury via an anti-inflammatory effect

PURPOSE

Acute respiratory distress syndrome is characterized by neutrophil accumulation in the lungs and the activation of several cytokines produced by macrophages. Olprinone hydrochloride, a specific phosphodiesterase III inhibitor, has anti-inflammatory effects and inhibits the activation of macrophages, in addition to its inotropic and vasodilatory effects. The purpose of this study was to examine the beneficial effects of olprinone on lipopolysaccharide (LPS)-induced pulmonary inflammation.

MATERIALS AND METHODS

Lung inflammation was produced by intravenous LPS injection into rats. The rats were divided into four groups: a vehicle group in which normal saline was injected, an olprinone group in which olprinone was injected at a dose of 0.2mg/kg, a dexamethasone group in which dexamethasone was injected at a dose of 5mg/kg, and a control group. In each group, drug was injected intraperitoneally 30 min before the intravenous administration of LPS. The blood was obtained at 1h and then animals were sacrificed at 6h and blood and lung specimen were obtained for cytokine analysis and pathological examination. On another set of experiment, bronchioloalveolar lavage (BAL) was performed for cytokine analysis of BAL fluid. The macrophages isolated from normal rat by BAL were cultured in vitro with the presence of LPS and olprinone or dexamethasone, and supernatant was collected. The levels of several cytokines in the serum, in the BAL fluid, and in the culture supernatant were determined.

RESULTS

The animals injected with LPS were found to have an influx of neutrophils in the lungs, and inflammatory cytokines, such as TNF-alpha and IL-6, and anti-inflammatory cytokine IL-10 were produced. Pretreatment with olprinone or dexamethasone significantly inhibited the LPS-induced neutrophil influx into the lungs, suppressed inflammatory cytokines TNF-alpha and IL-6. The level of anti-inflammatory cytokine IL-10 increased in an olprinone group. The inhibition of TNF-alpha and IL-6, and the augmentation of IL-10 release were also observed in in vitro culture of isolated rat alveolar macrophages when olprinone (10(-5)mol/ml) and LPS (10 microg/ml) were cultured together. However, the level of IL-10 in serum and culture supernatant was suppressed in a dexamesathone group.

CONCLUSION

LPS-induced lung inflammation is strongly inhibited by olprinone accompanying the enhancement of IL-10 and the inhibition of inflammatory cytokines. Results of the in vitro experiment suggest that alveolar macrophages may play an important role in ameliorating LPS-induced lung inflammation and the mechanism of its effect is different from that of steroid.

The role of bundles in sepsis care

The understanding of the pathogenesis of sepsis has substantially changed in past years and continues to improve. New therapeutic options are being developed and incorporated into clinical practice. There are different specific interventions and therapies that benefit patients' outcome. As demonstrated by the early goal-directed therapy strategy, the success of the resuscitation treatment is strongly time dependent. The recognition of severe sepsis should be accompanied without delay by very well defined therapeutic measures. In 2002 the Surviving Sepsis Campaign was introduced with the overall goal of increasing clinicians' awareness and improving outcome in severe sepsis and septic shock.

Limitations of clinical trials in acute lung injury and acute respiratory distress syndrome

PURPOSE OF REVIEW

To review the challenges and limitations of randomized clinical trials in acute respiratory distress syndrome, with special emphasis on those pertaining to ventilatory management.

RECENT FINDINGS

Superbly executed randomized trials of ventilatory strategy have garnered deserved attention from the critical care community and yet have illustrated the limitations of our current approach to clinical research in this area. Inexact definitions, incomplete mechanistic understanding of complex pathophysiology, inappropriate outcome variables, diverse therapeutic environments, lengthy data acquisition time and ethical constraints on trial design limit the applicability of randomized control trial methodology to acute respiratory distress syndrome and acute lung injury. As yet, clinical practice does not seem to have been greatly impacted by the implications of completed randomized controlled trials per se. Recent issues, both ethical and interpretive, regarding control group participants have raised troubling and theoretically important issues that are yet to be fully resolved.

SUMMARY

Without tighter definitions of the condition under treatment, more specific targets for interventions to act upon, stratification that recognizes key interactive elements, and cointerventions based on better mechanistic understanding, randomized controlled trials of new drugs, ventilatory strategy, and other management approaches in acute respiratory distress syndrome are likely to remain a blunt instrument for investigation. As valuable as they are for calling important therapeutic principles to attention and for helping to suggest general guidelines for care, the limitations of randomized controlled trials for treating the individual with acute respiratory distress syndrome must be acknowledged.

Postoperative acute respiratory distress syndrome development in the thoracic surgery patient

Acute respiratory distress syndrome (ARDS) in the thoracic surgery patient is a dreaded complication that occurs in 4% to 5% of pneumonectomies. This peculiar syndrome is indistinct from other forms of ARDS yet is associated with an exceedingly higher mortality rate. Current management parallels ARDS treatment of other etiologies.

Polymorphism of the angiotensin-converting enzyme gene affects the outcome of acute respiratory distress syndrome

OBJECTIVE

There has been increasing evidence that angiotensin II may play an important role in the pathogenesis and in the evolution of acute lung injury. It was therefore hypothesized that polymorphisms of the angiotensin-converting enzyme gene affects the risk and outcome of acute respiratory distress syndrome (ARDS).

DESIGN

Prospective, observational study.

PATIENTS AND SETTINGS

The ARDS group consisted of 101 patients treated at the medical intensive care unit; the control groups consisted of 138 "at-risk" patients treated at the medical intensive care unit due to acute respiratory failure but did not meet the ARDS criteria throughout the hospital course, and 210 non-at-risk subjects.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The ARDS patients and control subjects were genotyped for the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme gene. Association of the polymorphism and the risk and the outcome of ARDS was analyzed. There was no significant difference in the frequencies of the genotypes between the ARDS, at-risk, and non-at-risk groups. The 28-day mortality rates were significantly different between the three angiotensin-converting enzyme genotypes (42%, 65%, and 75% for II, ID, and DD, respectively; p = .036). Survival analysis showed that the II genotype favorably affected 28-day survival (hazard ratio, 0.46; 95% confidence interval, 0.26-0.81; p = .007), whereas ARDS caused by hospital-acquired pneumonia had a negative effect (hazard ratio, 2.34; 95% confidence interval, 1.25-4.40; p = .008). The II genotype (hazard ratio, 0.53; 95% confidence interval, 0.32-0.87; p = .012) and ARDS caused by hospital-acquired pneumonia (hazard ratio, 2.13; 95% confidence interval, 1.24-3.68; p = .006) were also significant prognostic factors for the in-hospital mortality.

CONCLUSIONS

The angiotensin-converting enzyme I/D polymorphism is a significant prognostic factor for the outcome of ARDS. Patients with the II genotype have a significantly better chance of survival. This study did not show an increased risk for ARDS in Chinese patients with the D allele.

Management of sepsis in neutropenia: guidelines of the infectious diseases working party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

These guidelines from the infectious diseases working party (AGIHO) of the German Society of Hematology and Oncology (DGHO) give recommendations for the management of adults with neutropenia and the diagnosis of sepsis. The guidelines are written for clinicians and focus on pathophysiology, diagnosis, and treatment of sepsis. The manuscript contains evidence-based recommendations for the assessment of the quality and strength of the data.

High-volume hemofiltration as salvage therapy in severe hyperdynamic septic shock

OBJECTIVES

To evaluate the effect of short-term (12-h) high-volume hemofiltration (HVHF) in reversing progressive refractory hypotension and hypoperfusion in patients with severe hyperdynamic septic shock. To evaluate feasibility and tolerance and to compare observed vs. expected hospital mortality.

DESIGN AND SETTING

Prospective, interventional, nonrandomized study in the surgical-medical intensive care unit of an academic tertiary center.

PATIENTS

Twenty patients with severe septic shock, previously unresponsive to a multi-intervention approach within a goal-directed, norepinephrine-based algorithm, with increasing norepinephrine (NE) requirements (>0.3 microg kg(-1) min(-1)) and lactic acidosis.

INTERVENTIONS

Single session of 12-h HVHF.

MEASUREMENTS AND RESULTS

We measured changes in NE requirements and perfusion parameters every 4h during HVHF and 6h thereafter. Eleven patients showed decreased NE requirements and lactate levels (responders). Nine patients did not fulfill these criteria (nonresponders). The NE dose, lactate levels, and heart rates decreased and arterial pH increased significantly in responders. Hospital mortality (40%) was significantly lower than predicted (60%): 67% (6/9) in nonresponders vs. 18% (2/11) in responders. Of 12 survivors 7 required only a single 12-h HVHF session. On logistic regression analysis the only statistically significant predictor of survival was theresponse to HVHF (odds ratio 9).

CONCLUSIONS

A single session of HVHF as salvage therapy in the setting of a goal-directed hemodynamic management algorithm may be beneficial in severe refractory hyperdynamic septic-shock patients. This approach may improve hemodynamics and perfusion parameters, acid-base status, and ultimately hospital survival. Moreover, it is feasible, and safe.

Severe Sepsis and Septic Shock in Adult Patients: An Approach to Management and Future Trends

Severe sepsis is sepsis associated with acute organ dysfunction. Septic shock in turn, implies severe sepsis that has led to circulatory shock refractory to fluid resuscitation alone. The immediate approach to severe sepsis follows the ABCs of resuscitation: Airway, Breathing, and Circulation. Special emphasis on the circulation involves early goal-directed therapy, adequate fluid resuscitation, and vasopressor/inotropic support. Once the patient's cardiorespiratory status is stabilized, efforts must be directed at uncovering the source and empirically yet accurately treating the infective underpinnings of severe sepsis. Following that, each of the patient's other organ systems at risk needs to be addressed: Renal/metabolic, gastrointestinal, hematological, and endocrine. Novel treatments will target both the proinflammatory and procoagulation cascades of sepsis.

Early perioperative death associated with reexpansion pulmonary edema during liver transplantation

Hydrothorax is a frequent finding in patients with end-stage liver disease. During the hepatectomy phase of liver transplantation, it is often needed to evacuate large pleural effusions. The acute expansion of the collapsed lung can cause reexpansion pulmonary edema with variable clinical significance. However, this complication has rarely been reported after liver transplantation. In conclusion, we report on an overwhelming reexpansion pulmonary edema during a liver transplantation that rapidly led to the patient's demise and speculate if this condition has not been under recognized in the transplantation setting.

Pilzsepsis - Therapeutische Strategie. Fungal sepsis - therapeutical strategy

The incidence of fungal infection as well as fungal sepsis has increased dramatically during the last decade. Changes of local microbial flora after broad-spectrum antibiotic therapy allow overgrowth of Candida species. Prophylactic strategies to lower fungal infection and sepsis include adequate and restrictive antibiotic therapy. Concerning the treatment of the septic syndrome, supportive as well as adjunctive strategies like early-goal-directed cardiovascular therapy, hydrocortisone replacement therapy, intense insulin application to achieve normoglycemia as well as the application of activated Protein C besides a consequent source control regimen and standard intensive care therapy, are able to improve significantly the outcome of septic patients.