Mechanical ventilation guided by esophageal pressure in acute lung injury.

BACKGROUND: Survival of patients with acute lung injury or the acute respiratory distress syndrome (ARDS) has been improved by ventilation with small tidal volumes and the use of positive end-expiratory pressure (PEEP); however, the optimal level of PEEP has been difficult to determine. In this pilot study, we estimated transpulmonary pressure with the use of esophageal balloon catheters. We reasoned that the use of pleural-pressure measurements, despite the technical limitations to the accuracy of such measurements, would enable us to find a PEEP value that could maintain oxygenation while preventing lung injury due to repeated alveolar collapse or overdistention. METHODS: We randomly assigned patients with acute lung injury or ARDS to undergo mechanical ventilation with PEEP adjusted according to measurements of esophageal pressure (the esophageal-pressure-guided group) or according to the Acute Respiratory Distress Syndrome Network standard-of-care recommendations (the control group). The primary end point was improvement in oxygenation. The secondary end points included respiratory-system compliance and patient outcomes. RESULTS: The study reached its stopping criterion and was terminated after 61 patients had been enrolled. The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen at 72 hours was 88 mm Hg higher in the esophageal-pressure-guided group than in the control group (95% confidence interval, 78.1 to 98.3; P=0.002). This effect was persistent over the entire follow-up time (at 24, 48, and 72 hours; P=0.001 by repeated-measures analysis of variance). Respiratory-system compliance was also significantly better at 24, 48, and 72 hours in the esophageal-pressure-guided group (P=0.01 by repeated-measures analysis of variance). CONCLUSIONS: As compared with the current standard of care, a ventilator strategy using esophageal pressures to estimate the transpulmonary pressure significantly improves oxygenation and compliance. Multicenter clinical trials are needed to determine whether this approach should be widely adopted. (ClinicalTrials.gov number, NCT00127491.)

The costs and cost-effectiveness of an integrated sepsis treatment protocol.

CONTEXT: Sepsis is associated with high mortality and treatment costs. International guidelines recommend the implementation of integrated sepsis protocols; however, the true cost and cost-effectiveness of these are unknown. OBJECTIVE: To assess the cost-effectiveness of an integrated sepsis protocol, as compared with conventional care. DESIGN: Prospective cohort study of consecutive patients presenting with septic shock and enrolled in the institution's integrated sepsis protocol. Clinical and economic outcomes were compared with a historical control cohort. SETTING: Beth Israel Deaconess Medical Center. PATIENTS: Overall, 79 patients presenting to the emergency department with septic shock in the treatment cohort and 51 patients in the control group. INTERVENTIONS: An integrated sepsis treatment protocol incorporating empirical antibiotics, early goal-directed therapy, intensive insulin therapy, lung-protective ventilation, and consideration for drotrecogin alfa and steroid therapy. MAIN OUTCOME MEASURES: In-hospital treatment costs were collected using the hospital's detailed accounting system. The cost-effectiveness analysis was performed from the perspective of the healthcare system using a lifetime horizon. The primary end point for the cost-effectiveness analysis was the incremental cost per quality-adjusted life year gained. RESULTS: Mortality in the treatment group was 20.3% vs. 29.4% in the control group (p = .23). Implementing an integrated sepsis protocol resulted in a mean increase in cost of approximately $8,800 per patient, largely driven by increased intensive care unit length of stay. Life expectancy and quality-adjusted life years were higher in the treatment group; 0.78 and 0.54, respectively. The protocol was associated with an incremental cost of $11,274 per life-year saved and a cost of $16,309 per quality-adjusted life year gained. CONCLUSIONS: In patients with septic shock, an integrated sepsis protocol, although not cost-saving, appears to be cost-effective and compares very favorably to other commonly delivered acute care interventions.

A novel method of continuous measurement of head of bed elevation in ventilated patients.

OBJECTIVE: We developed a novel pressure transducer-based method of continuous measurement of head of bed elevation. Following validation of the method we hypothesized that head of bed angles would be at or above 30 degrees among mechanically ventilated patients throughout the day due to a hospital-wide initiative on ventilator-associated pneumonia prevention and standardized electronic order entry system to keep head of bed at an angle of 30 degrees or greater. DESIGN AND SETTING: Prospective observational study in university hospital intensive care units. PATIENTS AND PARTICIPANTS: Twenty-nine consecutive mechanically ventilated patients with no contraindications for semirecumbency. MEASUREMENTS AND RESULTS: We acquired 113 pairs of measurements on unused beds for validation of the method at angles between 3 degrees and 70 degrees. Correlation between transducer and protractor was fitted into a linear regression model (R2 = 0.98) with minimal variation of data along the line of equality. Bland-Altman analysis showed a mean difference of 1.6 degrees +/- 1.6 degrees. Ninety-six percent of differences were within 2 SD from the mean. This method was then used among 29 intubated patients to collect head of bed data over a 24-h period for 3 consecutive days. Contrary to our hypothesis, all patients had head of bed angles less than 30 degrees. CONCLUSIONS: Our results suggest that this method could be used with high reliability and patients in our institution were not kept even at 30 degrees. The results are in accord with those of a recent study which found that continued maintenance of previously suggested head of bed angles was difficult to attain clinically. This may lead us to reevaluate methods studying the impact of head of bed elevation in VAP prevention.

Bedside ultrasonography in the differential diagnosis of pulmonary pathologies in the intensive care unit.

Among critically ill patients, opacification of a part or whole lung field on chest radiography may pose a challenge in the differential diagnosis of acute pulmonary pathologies (eg, pneumothorax, hemothorax, pleural effusion, atelectasis, and solid organ in thoracic cavity) and selection of treatment modalities. In cases in which clinical findings, history, and imaging studies are not conclusive, bedside ultrasonography may be invaluable in achieving a diagnosis. We present two cases in which portable ultrasonography at the bedside was critical to the diagnosis and subsequent management of the patient.

Intraoperative interventions: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery.

A comprehensive evidence review was conducted of the medical literature regarding the relationship between intraoperative interventions and the incidence of postoperative atrial arrhythmias, including, most commonly, atrial fibrillation (AF). Fifteen randomized, controlled studies and one large-scale concurrent cohort study were identified that reported on the following issues: systemic temperature during surgery (one report); "beating heart" surgery vs conventional bypass surgery (three reports); type of myocardial protection (five reports); the use of adjunctive posterior pericardiotomy (one report); the use of thoracic epidural anesthesia (TEA) [two reports]; the use of glucose-insulin-potassium (GIK) solutions (two reports); and the use of heparin-coated circuits for cardiopulmonary bypass (CPB) [two reports]. Based on a systematic review of the reported data and an analysis of the quality of the reported data, we recommend the following: (1) that mild hypothermia, rather than moderate hypothermia, may be effective in reducing the frequency of postoperative AF; (2) the use of posterior pericardiotomy may be a useful adjunct to reduce the frequency of postoperative AF; and (3) the use of heparin-coated CPB circuits is associated with less postoperative AF. Because of conflicting or inadequate data, we cannot conclude that the frequency of postoperative AF is affected by (1) the use of beating-heart techniques, (2) the type of myocardial protection strategy used, (3) the use of TEA, or (4) the use of GIK solutions perioperatively.

Serum lactate as a predictor of mortality in emergency department patients with infection.

STUDY OBJECTIVE: Little is known about risk-stratification biomarkers in emergency department (ED) patients with suspected infection, and lactate is a biologically plausible candidate. We determine whether a serum venous lactate is associated with an increased risk of death in ED patients with infection. METHODS: This was a prospective cohort study in an urban, academic medical center with 50,000 annual ED visits. A total of 1,278 consecutive patient visits met enrollment criteria between July 24, 2003, and March 24, 2004, and all patients were enrolled. Inclusion criteria were age 18 years or older, serum lactate level obtained, and admission to the hospital with an infection-related diagnosis. The main outcome measure was all-cause 28-day inhospital mortality and death within 3 days of presentation. RESULTS: Among 1,278 patient visits, there were 105 (8.2%) deaths during hospitalization, with 55 (4.3%) of 1,278 deaths occurring in the first 3 days. Mortality rates increased as lactate increased: 43 (4.9%) of 877 of patients with a lactate level between 0 and 2.5 mmol/L died, 24 (9.0%) of 267 patients with a lactate level between 2.5 and 4.0 mmol/L died, and 38 (28.4%) of 134 patients with a lactate level greater than or equal to 4.0 mmol/L died. Lactate level greater than or equal to 4.0 mmol/L was 36% (95% confidence interval [CI] 27% to 45%) sensitive and 92% (95% CI 90% to 93%) specific for any death; it was 55% (95% CI 41% to 68%) sensitive and 91% (95% CI 90% to 93%) specific for death within 3 days. CONCLUSION: In this cohort of ED patients with signs and symptoms suggestive of infection, our results support serum venous lactate level as a promising risk-stratification tool. Multicenter validation, as well as comparison of the lactate level with clinical predictors, needs to be done before widespread implementation.

Roundtable debate: Controversies in the management of the septic patient--desperately seeking consensus.

Despite continuous advances in technologic and pharmacologic management, the mortality rate from septic shock remains high. Care of patients with sepsis includes measures to support the circulatory system and treat the underlying infection. There is a substantial body of knowledge indicating that fluid resuscitation, vasopressors, and antibiotics accomplish these goals. Recent clinical trials have provided new information on the addition of individual adjuvant therapies. Consensus on how current therapies should be prescribed is lacking. We present the reasoning and preferences of a group of intensivists who met to discuss the management of an actual case. The focus is on management, with emphasis on the criteria by which treatment decisions are made. It is clear from the discussion that there are areas where there is agreement and areas where opinions diverge. This presentation is intended to show how experienced intensivists apply clinical science to their practice of critical care medicine.

Dopexamine, dobutamine, and dopamine increase splanchnic blood flow: what is the evidence?

Inadequate splanchnic perfusion in the critically ill compromises the gut barrier leading to bacterial translocation, which is postulated to cause multiorgan dysfunction and failure. Inotropic agents such as dopexamine, dobutamine, and dopamine may have a role in increasing splanchnic perfusion, thereby protecting this area from further injury. This article examines the evidence for using these agents in patients with sepsis, postoperative trauma, and in those undergoing cardiac surgery and mechanical ventilation to increase gut perfusion and prevent multiple organ failure. Systemic effects of these agents differ from regional effects and must be considered when selecting therapy.

Angiographic detection of carotid and vertebral arterial injury in the high-energy blunt trauma patient.

BACKGROUND AND OBJECTIVE: Injury to the carotid and vertebral arteries is an identified risk to patients after blunt high-energy cranio-cervical trauma with an associated risk of thromboembolic stroke. We sought to determine the incidence, features, and risk factors of arterial injury using selective cerebral angiography in a high-risk trauma patient subset. METHODS: Blunt trauma patients with a high-energy mechanism were selected to undergo screening cerebral angiography if they met one of the following criteria: (1) cervical spine hyperextension/hyperflexion injury, (2) skull-base or facial fracture, (3) lateralizing neurologic deficit, ischemic deficit, or cerebral infarction, or (4) hemorrhage of arterial origin. RESULTS: Of 69 screened patients 20 were found to have a vascular injury (28.9%), including 13 carotid and 15 vertebral; 9 of the 20 patients with vascular injury were symptomatic (45%). The most frequent injuries were intimal dissections (8/28), pseudoaneurysms (6/28), and vessel occlusions (5/28); 8 lesions were intracranial and 20 cervical. Displaced facial fractures (P<0.02) but not skull-base fracture were predictive of carotid injury; multilevel cervical spine fractures (P<0.001) and transverse foraminal fractures (P<0.02) were associated with vertebral injury. CONCLUSIONS: Cerebral angiography in a selected group of trauma patients was found to yield a significant rate of carotid and vertebral arterial injury, a finding that had implications to subsequent clinical management.

Low-dose dopamine in the intensive care unit.

For much of the last four decades, low-dose dopamine has been considered the drug of choice to treat and prevent renal failure in the intensive care unit (ICU). The multifactorial etiology of renal failure in the ICU and the presence of coexisting multisystem organ dysfunction make the design and execution of clinical trials to study this problem difficult. However, in the last decade, several meta-analyses and one large randomized trial have all shown a lack of benefit of low-dose dopamine in improving renal function. There are multiple reasons for this lack of efficacy. While dopamine does cause a diuretic effect, it does very little to improve mortality, creatinine clearance, or the incidence of dialysis. Evidence is also growing of its adverse effects on the immune, endocrine, and respiratory systems. It may also potentially increase mortality in sepsis. It is the opinion of the authors that the practice of using low-dose dopamine should be abandoned. Other drugs and treatment modalities need to be explored to address the serious issue of renal failure in the ICU.

Esophageal and transpulmonary pressures in acute respiratory failure.

OBJECTIVE: Pressure inflating the lung during mechanical ventilation is the difference between pressure applied at the airway opening (Pao) and pleural pressure (Ppl). Depending on the chest wall's contribution to respiratory mechanics, a given positive end-expiratory and/or end-inspiratory plateau pressure may be appropriate for one patient but inadequate or potentially injurious for another. Thus, failure to account for chest wall mechanics may affect results in clinical trials of mechanical ventilation strategies in acute respiratory distress syndrome. By measuring esophageal pressure (Pes), we sought to characterize influence of the chest wall on Ppl and transpulmonary pressure (PL) in patients with acute respiratory failure. DESIGN: Prospective observational study. SETTING: Medical and surgical intensive care units at Beth Israel Deaconess Medical Center. PATIENTS: Seventy patients with acute respiratory failure. INTERVENTIONS: Placement of esophageal balloon-catheters. MEASUREMENTS AND MAIN RESULTS: Airway, esophageal, and gastric pressures recorded at end-exhalation and end-inflation Pes averaged 17.5 +/- 5.7 cm H2O at end-expiration and 21.2 +/- 7.7 cm H2O at end-inflation and were not significantly correlated with body mass index or chest wall elastance. Estimated PL was 1.5 +/- 6.3 cm H2O at end-expiration, 21.4 +/- 9.3 cm H2O at end-inflation, and 18.4 +/- 10.2 cm H2O (n = 40) during an end-inspiratory hold (plateau). Although PL at end-expiration was significantly correlated with positive end-expiratory pressure (p < .0001), only 24% of the variance in PL was explained by Pao (R = .243), and 52% was due to variation in Pes. CONCLUSIONS: In patients in acute respiratory failure, elevated esophageal pressures suggest that chest wall mechanical properties often contribute substantially and unpredictably to total respiratory impedance, and therefore Pao may not adequately predict PL or lung distention. Systematic use of esophageal manometry has the potential to improve ventilator management in acute respiratory failure by providing more direct assessment of lung distending pressure.

Implementation and outcomes of the Multiple Urgent Sepsis Therapies (MUST) protocol.

OBJECTIVES: To describe the effectiveness of a comprehensive, interdisciplinary sepsis treatment protocol with regard to both implementation and outcomes and to compare the mortality rates and therapies of patients with septic shock with similar historical controls. DESIGN: Prospective, interventional cohort study with a historical control comparison group. SETTING: Urban, tertiary care, university hospital with 46,000 emergency department visits and 4,100 intensive care unit admissions annually. PATIENTS: Inclusion criteria were a) emergency department patients aged > or =18 yrs, b) suspected infection, and c) lactate of >4 mmol/L or septic shock. Exclusion criteria were a) emergent operation, b) prehospital cardiac arrest, and c) comfort measures only. Time period: protocol, November 10, 2003, through November 9, 2004; historical controls, February 1, 2000, through January 31, 2001. INTERVENTION: A sepsis treatment pathway incorporating empirical antibiotics, early goal-directed therapy, drotrecogin alfa, steroids, intensive insulin therapy, and lung-protective ventilation. MEASUREMENTS AND MAIN RESULTS: There were 116 protocol patients, with a mortality rate of 18% (11-25%), of which 79 patients had septic shock. Comparing these patients with 51 historical controls, protocol patients received more fluid (4.0 vs. 2.5 L crystalloid, p < .001), earlier antibiotics (90 vs. 120 mins, p < .013), more appropriate empirical coverage (97% vs. 88%, p < .05), more vasopressors in the first 6 hrs (80% vs. 45%, p < .001), tighter glucose control (mean morning glucose, 123 vs. 140, p < .001), and more frequent assessment of adrenal function (82% vs. 10%, p < .001), with a nonstatistically significant increase in dobutamine use (14% vs. 4%, p = .06) and red blood cell transfusions (30% vs. 18%, p = .07) in the first 24 hrs. For protocol patients with septic shock, 28-day in-hospital mortality was 20.3% compared with 29.4% for historical controls (p = .3). CONCLUSIONS: Clinical implementation of a comprehensive sepsis treatment protocol is feasible and is associated with changes in therapies such as time to antibiotics, intravenous fluid delivery, and vasopressor use in the first 6 hrs. No statistically significant decrease in mortality was demonstrated, as this trial was not sufficiently powered to assess mortality benefits.

Persistent left superior vena cava identified after cannulation of the right subclavian vein.

IMPLICATIONS: We report the case of a patient with a chest radiograph suggestive of intraarterial placement of a central venous catheter. On investigation, the catheter was located in a previously undiagnosed persistent left superior vena cava.