Frequency of mortality and myocardial infarction during maximizing oxygen delivery: a prospective, randomized trial

A randomized controlled trial on the effects of goal-directed therapy on the inflammatory response open abdominal aortic aneurysm repair

Introduction

Goal-directed therapy (GDT) has been shown in numerous studies to decrease perioperative morbidity and mortality. The mechanism of benefit of GDT, however, has not been clearly elucidated. Targeted resuscitation of the vascular endothelium with GDT might alter the postoperative inflammatory response and be responsible for the decreased complications with this therapy.

Methods

This trial was registered at ClinicalTrials.gov as NCT01681251. Forty patients undergoing elective open repair of their abdominal aortic aneurysm, 18 years of age and older, were randomized to an interventional arm with GDT targeting stroke volume variation with an arterial pulse contour cardiac output monitor, or control, where fluid therapy was administered at the discretion of the attending anesthesiologist. We measured levels of several inflammatory cytokines (C-reactive protein, Pentraxin 3, suppressor of tumorgenicity--2, interleukin-1 receptor antagonist, and tumor necrosis factor receptor-III) preoperatively and at several postoperative time points to determine if there was a difference in inflammatory response. We also assessed each group for a composite of postoperative complications.

Results

Twenty patients were randomized to GDT and twenty were randomized to control. Length of stay was not different between groups. Intervention patients received less crystalloid and more colloid. At the end of the study, intervention patients had a higher cardiac index (3.4 ± 0.5 vs. 2.5 ± 0.7 l/minute per m², p < 0.01) and stroke volume index (50.1 ± 7.4 vs. 38.1 ± 9.8 ml/m², p < 0.01) than controls. There were significantly fewer complications in the intervention than control group (28 vs. 12, p = 0.02). The length of hospital and ICU stay did not differ between groups. There was no difference in the levels of inflammatory cytokines between groups.

Conclusions

Despite being associated with fewer complications and improved hemodynamics, there was no difference in the inflammatory response of patients treated with GDT. This suggests that the clinical benefit of GDT occurs in spite of a similar inflammatory burden. Further work needs to be performed to delineate the mechanism of benefit of GDT.

Trial registration

ClinicalTrials.gov Identifier: NCT01681251. Registered 18 May 2011.

Pulmonary artery catheters for adult patients in intensive care

BACKGROUND

Since pulmonary artery balloon flotation catheterization was first introduced in 1970, by HJ Swan and W Ganz, it has been widely disseminated as a diagnostic tool without rigorous evaluation of its clinical utility and effectiveness in critically ill patients. A pulmonary artery catheter (PAC) is inserted through a central venous access into the right side of the heart and floated into the pulmonary artery. PAC is used to measure stroke volume, cardiac output, mixed venous oxygen saturation and intracardiac pressures with a variety of additional calculated variables to guide diagnosis and treatment. Complications of the procedure are mainly related to line insertion. Relatively uncommon complications include cardiac arrhythmias, pulmonary haemorrhage and infarct, and associated mortality from balloon tip rupture.

OBJECTIVES

To provide an up-to-date assessment of the effectiveness of a PAC on mortality, length of stay (LOS) in intensive care unit (ICU) and hospital and cost of care in adult intensive care patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 12); MEDLINE (1954 to January 2012); EMBASE (1980 to January 2012); CINAHL (1982 to January 2012), and reference lists of articles. We contacted researchers in the field. We did a grey literature search for articles published until January 2012.

SELECTION CRITERIA

We included all randomized controlled trials conducted in adults ICUs, comparing management with and without a PAC.

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts and then the full text reports identified from our electronic search. Two authors (SR and MG) independently reviewed the titles, abstracts and then the full text reports for inclusion. We determined the final list of included studies by discussion among the group members (SR, ND, MG, AK and SC) with consensus agreement. We included all the studies that were in the original review. We assessed seven domains of potential risk of bias for the included studies. We examined the clinical, methodological and statistical heterogeneity and used random-effects model for meta-analysis. We calculated risk ratio for mortality across studies and mean days for LOS.

MAIN RESULTS

We included 13 studies (5686 patients). We judged blinding of participants and personnel and blinding of outcome assessment to be at high risk in about 50% of the included studies and at low risk in 25% to 30% of the studies. Regardless of the high risk of performance bias these studies were included based on the low weight the studies had in the meta-analysis. We rated 75% of the studies as low risk for selection, attrition and reporting bias. All 13 studies reported some type of hospital mortality (28-day, 30-day, 60-day or ICU mortality). We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (five studies) separately as subgroups for meta-analysis. The pooled risk ratio (RR) for mortality for the studies of general intensive care patients was 1.02 (95% confidence interval (CI) 0.96 to 1.09) and for the studies of high-risk surgery patients the RR was 0.98 (95% CI 0.74 to 1.29). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. PAC did not affect general ICU LOS (reported by four studies) or hospital LOS (reported by nine studies). Four studies, conducted in the United States (US), reported costs based on hospital charges billed, which on average were higher in the PAC groups. Two of these studies qualified for analysis and did not show a statistically significant hospital cost difference (mean difference USD 900, 95% CI -2620 to 4420, P = 0.62).

AUTHORS' CONCLUSIONS

PAC is a diagnostic and haemodynamic monitoring tool but not a therapeutic intervention. Our review concluded that use of a PAC did not alter the mortality, general ICU or hospital LOS, or cost for adult patients in intensive care. The quality of evidence was high for mortality and LOS but low for cost analysis. Efficacy studies are needed to determine if there are optimal PAC-guided management protocols, which when applied to specific patient groups in ICUs could result in benefits such as shock reversal, improved organ function and less vasopressor use. Newer, less-invasive haemodynamic monitoring tools need to be validated against PAC prior to clinical use in critically ill patients.

The evolving concepts of haemodynamic support: from pulmonary artery catheter to echocardiography and theragnostics

Echocardiography is a non-invasive tool, aimed towards the anatomical and functional characterization of the heart. In Intensive Care it is considered nowadays as a necessary tool for patient evaluation. However, the information obtained using echocardiography is not the same as provided by other means, namely the invasive ones. In recent years there has been a significant evolution in the general concepts of haemodynamic support for the critically ill patient. In this new environment, echocardiography has gained particular relevance. In this text the new positioning of echocardiography in the light of the new concepts for hemodynamic support is described, as well as, the need for a specific formative program directed towards Intensive Care physicians. A new generation of biomarkers can also add relevant information and start a new era in haemodynamic support. They may help to further characterize the disease process, identifying patients at risk, as well as, characterize specific organ failure as well as monitoring therapy.

Perioperative increase in global blood flow to explicit defined goals and outcomes following surgery

BACKGROUND

Studies have suggested that increasing whole body blood flow and oxygen delivery around the time of surgery reduces mortality, morbidity and the expense of major operations.

OBJECTIVES

To describe the effects of increasing perioperative blood flow using fluids with or without inotropes or vasoactive drugs. Outcomes were mortality, morbidity, resource utilization and health status.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library 2012, Issue 1), MEDLINE (1966 to March 2012) and EMBASE (1982 to March 2012). We manually searched the proceedings of major conferences and personal reference databases up to December 2011. We contacted experts in the field and pharmaceutical companies for published and unpublished data.

SELECTION CRITERIA

We included randomized controlled trials with or without blinding. We included studies involving adult patients (aged 16 years or older) undergoing surgery (patients having a procedure in an operating room). The intervention met the following criteria. 'Perioperative' was defined as starting up to 24 hours before surgery and stopping up to six hours after surgery. 'Targeted to increase global blood flow' was defined by explicit measured goals that were greater than in controls, specifically one or more of cardiac index, oxygen delivery, oxygen consumption, stroke volume (and the respective derived indices), mixed venous oxygen saturation (SVO(2)), oxygen extraction ratio (0(2)ER) or lactate.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data. We contacted study authors for additional data. We used Review Manager software.

MAIN RESULTS

We included 31 studies of 5292 participants. There was no difference in mortality: 282/2615 (10.8%) died in the control group and 238/2677 (8.9%) in the treatment group, RR of 0.89 (95% CI 0.76 to 1.05, P = 0.18). However, the results were sensitive to analytical methods and the intervention was better than control when inverse variance or Mantel-Haenszel random-effects models were used, RR of 0.72 (95% CI 0.55 to 0.95, P = 0.02). The results were also sensitive to withdrawal of studies with methodological limitations. The rates of three morbidities were reduced by increasing global blood flow: renal failure, RR of 0.71 (95% CI 0.57 to 0.90); respiratory failure, RR of 0.51 (95% CI 0.28 to 0.93); and wound infections, RR of 0.65 (95% CI 0.51 to 0.84). There were no differences in the rates of nine other morbidities: arrhythmia, pneumonia, sepsis, abdominal infection, urinary tract infection, myocardial infarction, congestive cardiac failure or pulmonary oedema, or venous thrombosis. The number of patients with complications was reduced by the intervention, RR of 0.68 (95% CI 0.58 to 0.80). Hospital length of stay was reduced in the treatment group by a mean of 1.16 days (95% CI 0.43 to 1.89, P = 0.002). There was no difference in critical care length of stay. There were insufficient data to comment on quality of life and cost effectiveness.

AUTHORS' CONCLUSIONS

It remains uncertain whether increasing blood flow using fluids, with or without inotropes or vasoactive drugs, reduces mortality in adults undergoing surgery. The primary analysis in this review (mortality at longest follow-up) showed no difference between the intervention and control, but this result was sensitive to the method of analysis, the withdrawal of studies with methodological limitations, and is dominated by a single large RCT. Overall, for every 100 patients in whom blood flow is increased perioperatively to defined goals, one can expect 13 in 100 patients (from 40/100 to 27/100) to avoid a complication, 2/100 to avoid renal impairment (from 8/100 to 6/100), 5/100 to avoid respiratory failure (from 10/100 to 5/100), and 4/100 to avoid postoperative wound infection (from 10/100 to 6/100). On average, patients receiving the intervention stay in hospital one day less. It is unlikely that the intervention causes harm. The balance of current evidence does not support widespread implementation of this approach to reduce mortality but does suggest that complications and duration of hospital stay are reduced.

Rapid response systems

Intensive care medicine was for many years practiced within the four walls of an intensive care unit (ICU). Evidence then emerged that many serious adverse events in hospitals were preceded by many hours of slow deterioration, resulting in multi-organ failure and potentially preventable admissions to the ICU. Ironically, these admissions may have been prevented if the skills within the ICU had been available to the patient on the general ward at an earlier stage. The concept of a Medical Emergency Team (MET) was developed to enable staff from the ICU to rapidly identify and respond to serious illness at an earlier stage and, hopefully, prevent serious complications. Since then, other forms of rapid response and outreach systems have been developed. Increasingly, physicians working in ICUs can see the benefit of the early management of serious illness in order to improve patient outcome.

Medical and economic impact of anemia in hospitalized patients

PURPOSE

Studies indicate that the prevalence of anemia in a number of patient populations is more common than originally thought, and that more patients go untreated. Current trends in the prevalence of anemia and the consequences of untreated anemia are described.

SUMMARY

Untreated anemia is linked as an independent risk factor to increased mortality, morbidity, decreased efficacy of chemotherapy and radiotherapy in cancer treatment, and lengthened hospital or intensive care unit length of stay. Anemia is also associated with increased mortality in patients with congestive heart failure or left ventricular dysfunction.

CONCLUSION

Anemia is prevalent in the oncology and critical care populations, yet is a neglected diagnosis. It is well established that anemia has been associated with increased morbidity and mortality, and can adversely impact therapy effectiveness. Effective treatment of anemia should be based on an understanding of the patient's physiological response to anemia and achieving optimal oxygenation levels while minimizing risks and complications common to the critical care patient.

Hemodynamic patterns preceding circulatory deterioration and death after trauma

OBJECTIVE

To describe the sequence of hemodynamic changes associated with sudden circulatory deterioration compared with those of terminal patients to identify the earliest signs warning of shock and death.

METHODS

This is a prospective observational study of 89 patients with thermodilution cardiac index and continuous noninvasive hemodynamic monitoring who had episodes of circulatory deterioration. These data were compared with the data of a second group of 24 patients in their terminal stage just before death.

RESULTS

The earliest indications of impending collapse were decreased cardiac index, and tissue perfusion reflected by decreased transcutaneous O2 tension (PtcO2). This was followed by reduced blood pressure, tachycardia, reduced arterial hemoglobin saturation, and increased transcutaneous CO2 tension (PtcCO2). This pattern of changes was more pronounced in the nonsurvivors and was seen in exaggerated form in terminal patients.

CONCLUSION

Sequential hemodynamic patterns revealed reduced blood flow and poor tissue perfusion as the earliest warning signs in both circulatory deterioration and death. These were followed by reduced mean arterial pressure, tachycardia, and low values of pulse oximetry. Adequate blood flow and even distribution of flow are needed for tissue perfusion.

The incidence of myocardial injury following post-operative Goal Directed Therapy

BACKGROUND

Studies suggest that Goal Directed Therapy (GDT) results in improved outcome following major surgery. However, there is concern that pre-emptive use of inotropic therapy may lead to an increased incidence of myocardial ischaemia and infarction.

METHODS

Post hoc analysis of data collected prospectively during a randomised controlled trial of the effects of post-operative GDT in high-risk general surgical patients. Serum troponin T concentrations were measured at baseline and on day 1 and day 2 following surgery. Continuous ECG monitoring was performed during the eight hour intervention period. Patients were followed up for predefined cardiac complications. A univariate analysis was performed to identify any associations between potential risk factors for myocardial injury and elevated troponin T concentrations.

RESULTS

GDT was associated with fewer complications, and a reduced duration of hospital stay. Troponin T concentrations above 0.01 microg l-1 were identified in eight patients in the GDT group and six in the control group. Values increased above 0.05 microg l-1 in four patients in the GDT group and two patients in the control group. There were no overall differences in the incidence of elevated troponin T concentrations. The incidence of cardiovascular complications was also similar. None of the patients, in whom troponin T concentrations were elevated, developed ECG changes indicating myocardial ischaemia during the intervention period. The only factor to be associated with elevated troponin T concentrations following surgery was end-stage renal failure.

CONCLUSION

The use of post-operative GDT does not result in an increased incidence of myocardial injury.

Pulmonary artery catheters for adult patients in intensive care

BACKGROUND

Pulmonary artery catheterization was adopted about 30 years ago and widely disseminated without rigorous evaluation as to whether it benefited critically ill patients. The technique is used to measure cardiac output and pressures in the pulmonary circulation to guide diagnosis and treatment. Clinicians believe these data can improve patients' outcomes, even in the absence of consensus about the specific interpretation of the data.

OBJECTIVES

To assess the effect of pulmonary artery catheterization on mortality and cost of care in adult intensive care patients.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2006); MEDLINE (all records to April 2006); EMBASE (all records to April 2006); CINAHL (all records to April 2006) and reference lists of articles. We contacted manufacturers and researchers in the field.

SELECTION CRITERIA

We included all randomized controlled trials in adults, comparing management with and without a pulmonary artery catheter (PAC).

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts of the electronic search results and obtained the full text of studies of possible relevance for independent review. We determined the final results of the literature search by consensus between the authors. We did not contact study authors for additional information.

MAIN RESULTS

We identified 12 studies. Mortality was reported as hospital, 28-day, 30-day, or intensive care unit. We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (four studies) separately for the meta-analysis. The pooled odds ratio for the studies of general intensive care patients was 1.05 (95% confidence interval (CI) 0.87 to 1.26) and for the studies of high-risk surgery patients 0.99 (95% CI 0.73 to 1.24). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. Pulmonary artery catheterization did not affect intensive care unit (reported by 10 studies) or hospital (reported by nine studies) length of stay. Four studies, conducted in the United States, measured costs based on hospital charges billed to patients, which on average were higher in the PAC groups.

AUTHORS' CONCLUSIONS

To date, there have been two multi-centre trials of the effectiveness of PACs for managing critically ill patients admitted to intensive care, although only one was adequately powered. Efficacy studies are needed to determine optimal management protocols and patient groups who could benefit from management with a PAC.

Meta-analysis of hemodynamic optimization: relationship to methodological quality

Introduction

To review systematically the effect of interventions aimed at hemodynamic optimization and to relate this to the quality of individual published trials.

Methods

A systematic, computerized bibliographic search of published studies and citation reviews of relevant studies was performed. All randomized clinical trials in which adult patients were included in a trial deliberately aiming at an optimized or maximized hemodynamic condition of the patients (with oxygen delivery, cardiac index, oxygen consumption, mixed venous oxygen saturation and/or stroke volume as end-points) were selected. A total of 30 studies were selected for independent review. Two reviewers extracted data on population, intervention, outcome and methodological quality. Agreement between reviewers was high: differences were eventually resolved by third-party decision. The methodological quality of the studies was moderate (mean 9.0, SD 1.7), and the outcomes of the randomized clinical trials were not related to their quality.

Results

Efforts to achieve an optimized hemodynamic condition resulted in a decreased mortality rate (relative risk ratio (RR) 0.75 (95% confidence interval (CI) 0.62 to 0.90) in all studies combined. This was due to a significantly decreased mortality in peri-operative intervention studies (RR 0.66 (95% CI 0.54 to 0.81). Overall, patients with sepsis and overt organ failure do not benefit from this method (RR 0.92 (95% CI 0.75 to 1.11)).

Conclusion

This systematic review showed that interventions aimed at hemodynamic optimization reduced mortality. In particular, trials including peri-operative interventions aimed at the hemodynamic optimization of high-risk surgical patients reduce mortality. Overall, this effect was not related to the trial quality.

Relationship of pulmonary artery catheter use to mortality and resource utilization in patients with severe sepsis*

OBJECTIVE

To examine the relationship of pulmonary artery catheter (PAC) use to patient outcomes, including mortality rate and resource utilization, in patients with severe sepsis in eight academic medical centers.

DESIGN

Case-control, nested within a prospective cohort study.

SETTING

Eight academic tertiary care centers.

PATIENTS

Stratified random sample of 1,010 adult admissions with severe sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The main outcome measures were in-hospital mortality, total hospital charge, and length of stay (LOS) for patients with and without PAC use. The case-matched subset of patients included 141 pairs managed with and without the use of a PAC. The mortality rate was slightly but not statistically significantly lower among the PAC use group compared with those not using a PAC (41.1% vs. 46.8%, p =.34). Even this trend disappeared after we adjusted for the Charlson comorbidity score and sepsis-specific Acute Physiology and Chronic Health Evaluation (APACHE) III (adjusted odds ratio, 1.02; 95% confidence interval, 0.61-1.72). In linear regression models adjusted for the Charlson comorbidity score, sepsis-specific APACHE III, surgical status, receipt of a steroid before sepsis onset, presence of a Hickman catheter, and preonset LOS, no significant differences were found for total hospital charges (139,207 US dollars vs. 148,190, adjusted mean comparing PAC and non-PAC group, p =.57), postonset LOS (23.4 vs. 26.9 days, adjusted mean, p =.32), or total LOS in intensive care unit (18.2 vs. 18.8 days, adjusted mean, p =.82).

CONCLUSIONS

Among patients with severe sepsis, PAC placement was not associated with a change in mortality rate or resource utilization, although small nonsignificant trends toward lower resource utilization were present in the PAC group.

Goal-oriented shock resuscitation for major torso trauma: what are we learning?

Shock resuscitation is an obligatory intervention for severely injured patients who present in shock. During the past 15 years, with widespread acceptance of "damage control" surgery and early triage to the intensive care unit (ICU) to optimize resuscitation, the lives of many major trauma victims have been saved, and much has been learned about shock resuscitation. Due largely to the work of Shoemaker et al., a resuscitation strategy based on a standardized process using O(2) delivery index (DO(2)I) as an endpoint and physiologic performance goal for interventions has been developed, studied, and refined for resuscitation of shock caused by major trauma. DO(2)I >or=600 mL O(2)/min-m2 is the only resuscitation endpoint variable that has been tested in prospective randomized trials (PRTs) of trauma patient outcome. These PRTs are limited, and their results are not conclusive. Results from other investigators, including our group, using similar process and endpoints, are indicating similar performance and outcomes. We believe that DO(2)I is a useful endpoint because it integrates three important variables, ie, hemoglobin concentration [Hb], arterial hemoglobin O(2) saturation, and cardiac output. We have found DO(2)I >or=500 mL O(2)/min-m2 to be an endpoint with more general applicability, but we believe that the standardized process is more important than the specific endpoint. To standardize our process, we have developed a computerized decision support tool for shock resuscitation. This technology has provided novel data collection and has permitted refinement of the bedside process. Our data analysis indicates that the next challenge will be to develop a similar pre ICU resuscitation process that will use less invasive monitors and different endpoints. Identification of the high-risk resuscitation nonresponders early in the resuscitation process will be needed to redirect their clinical trajectories. As an endpoint for interventions for goal-directed resuscitation in the critically injured trauma patient, systemic O(2) delivery is the current state of the art and the basis for near future development of clinical processes for resuscitation of shock due to major trauma.

Severe sepsis: variation in resource and therapeutic modality use among academic centers

BACKGROUND

Treatment of severe sepsis is expensive, often encompassing a number of discretionary modalities. The objective of the present study was to assess intercenter variation in resource and therapeutic modality use in patients with severe sepsis.

METHODS

We conducted a prospective cohort study of 1028 adult admissions with severe sepsis from a stratified random sample of patients admitted to eight academic tertiary care centers. The main outcome measures were length of stay (LOS; total LOS and LOS after onset of severe sepsis) and total hospital charges.

RESULTS

The adjusted mean total hospital charges varied from 69 429 dollars to US237 898 dollars across centers, whereas the adjusted LOS after onset varied from 15.9 days to 24.2 days per admission. Treatments used frequently after the first onset of sepsis among patients with severe sepsis were pulmonary artery catheters (19.4%), ventilator support (21.8%), pressor support (45.8%) and albumin infusion (14.4%). Pulmonary artery catheter use, ventilator support and albumin infusion had moderate variation profiles, varying 3.2-fold to 4.9-fold, whereas the rate of pressor support varied only 1.92-fold across centers. Even after adjusting for age, sex, Charlson comorbidity score, discharge diagnosis-relative group weight, organ dysfunction and service at onset, the odds for using these therapeutic modalities still varied significantly across centers. Failure to start antibiotics within 24 hours was strongly correlated with a higher probability of 28-day mortality (r2 = 0.72).

CONCLUSION

These data demonstrate moderate but significant variation in resource use and use of technologies in treatment of severe sepsis among academic centers. Delay in antibiotic therapy was associated with worse outcome at the center level.

A randomized, controlled trial of the use of pulmonary-artery catheters in high-risk surgical patients

BACKGROUND

Some observational studies suggest that the use of pulmonary-artery catheters to guide therapy is associated with increased mortality.

METHODS

We performed a randomized trial comparing goal-directed therapy guided by a pulmonary-artery catheter with standard care without the use of a pulmonary-artery catheter. The subjects were high-risk patients 60 years of age or older, with American Society of Anesthesiologists (ASA) class III or IV risk, who were scheduled for urgent or elective major surgery, followed by a stay in an intensive care unit. Outcomes were adjudicated by observers who were unaware of the treatment-group assignments. The primary outcome was in-hospital mortality from any cause.

RESULTS

Of 3803 eligible patients, 1994 (52.4 percent) underwent randomization. The base-line characteristics of the two treatment groups were similar. A total of 77 of 997 patients who underwent surgery without the use of a pulmonary-artery catheter (7.7 percent) died in the hospital, as compared with 78 of 997 patients in whom a pulmonary-artery catheter was used (7.8 percent)--a difference of 0.1 percentage point (95 percent confidence interval, -2.3 to 2.5). There was a higher rate of pulmonary embolism in the catheter group than in the standard-care group (8 events vs. 0 events, P=0.004). The survival rates at 6 months among patients in the standard-care and catheter groups were 88.1 and 87.4 percent, respectively (difference, -0.7 percentage point [95 percent confidence interval, -3.6 to 2.2]; negative survival differences favor standard care); at 12 months, the rates were 83.9 and 83.0 percent, respectively (difference, -0.9 percentage point [95 percent confidence interval, -4.3 to 2.4]). The median hospital stay was 10 days in each group.

CONCLUSIONS

We found no benefit to therapy directed by pulmonary-artery catheter over standard care in elderly, high-risk surgical patients requiring intensive care.

The International Sepsis Forum's frontiers in sepsis: High cardiac output should not be maintained in severe sepsis

Abnormal oxygen utilisation is one of the features of septic shock. Some studies have observed that patients that survive septic shock tend to have higher cardiac output and oxygen delivery compared to those that do not. It has been proposed that higher than normal (or "supra-normal") levels of cardiac output and oxygen deliver should be the goal in the management of septic shock. However, randomised controlled trials have not been able to validate that such a goal provides a mortality or morbidity advantage. In this commentary we discuss the various reasons put forward by the proponents of this strategy and review the available evidence.

Critical care without walls

Critical care medicine is a relatively young specialty that was developed in response to potentially reversible life-threatening illness and was facilitated by developments such as new drugs, support equipment, and monitoring technology. It has been largely practiced within the four walls of an intensive care unit (ICU). However, now there are increasing numbers of critically ill and at-risk patients in acute hospitals who are suffering potentially preventable, serious complications that may result in death because of a lack of appropriate systems, skills, and expertise outside of the ICU. Critical care specialists are expanding their roles beyond the four walls of their ICUs and becoming involved with strategies such as the medical emergency team, a concept designed to recognize critical illness early and to respond rapidly to resuscitate patients wherever they are in the hospital.

Oxygen transport and organ dysfunction in the older trauma patient

OBJECTIVES

To determine baseline values of cardiac index (CI) and oxygen transport variables in patients with multiple trauma within 24 hours of admission to a level I trauma center.

METHOD

This project was part of a larger study comparing methods of measuring oxygen consumption (VO2) in 38 severely injured patients. Measurements of CI, oxygen delivery (DO2), and VO2 were performed every 6 hours for 24 hours. Patients were monitored for multiple organ dysfunction syndrome.

RESULTS

The mean age was 59 (+/- 17) years, with 74% (n = 28) of patients 50 years or older. Patients 65 years or older had significantly lower levels of CI, DO2, and VO2. Initial age-related differences in CI (P < .001) persisted at each time period (P < .0136). Younger patients generated a higher DO2 at each time period (P < .0005). Even though there were persistent age-related differences in VO2 over time (P < .0001), no interaction between age and time was found. Survivors had lower scores for multiple organ dysfunction syndrome than did nonsurvivors (P < .0001), all of whom were 50 years or older. Mortality was 21%.

CONCLUSIONS

All patients were hypermetabolic, but older patients were much less so. Younger patients progressively had increased CI and DO2 levels, whereas older patients started with low levels that remained so. Patients in each age group appeared to lock into a level of VO2 that did not change over time. These findings underscore the vulnerability of older patients to poor outcomes. As the magnitude of the postinjury response is partly age-dependent, future research should differentiate patient characteristics associated with positive outcomes among elderly trauma patients.

Meta-analysis of hemodynamic optimization in high-risk patients

OBJECTIVE

The aim of this evidence-based report was to review pertinent randomized controlled studies that describe hemodynamic goals in acute, critically ill patients and to evaluate outcome of resuscitation therapy in association with physiologic, clinical, and therapeutic influences.

METHODS

MEDLINE was the source of randomized controlled studies written in English. The inclusion criteria were acutely ill, high-risk elective surgery, trauma, and septic patients. The goals of therapy were to resuscitate to either normal or supranormal values; the latter were described as a cardiac index of >4.5 L x min(-1) x m(-2), pulmonary artery occlusion pressure of <18 mm Hg, oxygen delivery of >600 mL x min(-1) x m(-2), and oxygen consumption of >170 mL x min(-1) x m(-2). The outcome criterion was survival or death. We found 21 randomized clinical trials described in 20 articles. The studies were divided into groups based on the time that goals were implemented (i.e., "early," 8 to 12 hrs postoperatively or before organ failure, vs. "late," or after onset of organ failure) and the severity of illness, determined by the control group mortality as >20% (12 studies) or <15% (nine studies).

RESULTS

In severely ill patients (control mortalities group >20%), six studies had a 23% mortality difference (p <.05) between the control and protocol groups with early optimization, but seven studies optimized after the development of organ failure did not have significantly improved mortality. Moreover, outcome was not significantly improved in less severely ill patients (control mortalities group <15%) and normal values as goals or when therapy did not improve oxygen delivery.

CONCLUSION

Review of 21 randomized controlled trials with various approaches to treatment revealed statistically significant mortality reductions, with hemodynamic optimization, when patients with acute critical illness were treated early to achieve optimal goals before the development of organ failure, when there were control group mortalities of >20% and when therapy produced differences in oxygen delivery between the control and protocol groups.

Outcome prediction of emergency patients by noninvasive hemodynamic monitoring

OBJECTIVES

We used noninvasive hemodynamic monitoring in the initial resuscitation beginning in the emergency department (ED) for the following reasons: (1) to describe early survivor and nonsurvivor patterns of emergency patients in terms of cardiac, pulmonary, and tissue perfusion deficiencies; (2) to measure quantitatively the net cumulative amount of deficit or excess of the monitored functions that correlate with survival or death; and (3) to explore the use of discriminant analysis to predict outcome and evaluate the biological significance of monitored deficits.

METHODS

This is a descriptive study of the feasibility of noninvasive monitoring of patients with acute emergency conditions in the ED to evaluate and quantify hemodynamic deficits as early as possible. The noninvasive monitoring systems consisted of a bioimpedance method for estimating cardiac output together with pulse oximetry to reflect pulmonary function, transcutaneous oxygen tension to reflect tissue perfusion, and BP to reflect the overall circulatory status. These continuously monitored noninvasive measurements were used to prospectively evaluate circulatory patterns in 151 consecutively monitored severely injured patients beginning with admission to the ED in a university-run county hospital. The net cumulative deficit or excess of each monitored parameter was calculated as the cumulative difference from the normal value vs the time-integrated monitored curve for each patient. The deficits of cardiac, pulmonary, and tissue perfusion functions were analyzed in relation to outcome by discriminant analysis and were cross-validated.

RESULTS

The mean (+/- SEM) net cumulative excesses (+) or deficits (-) from normal in surviving vs nonsurviving patients, respectively, were as follows: cardiac index (CI), +81 +/- 52 vs -232 +/- 138 L/m(2) (p = 0.037); arterial hemoglobin saturation, -1 +/- 0.3 vs -8 +/- 2.6%/h (p = 0.006); and tissue perfusion, +313 +/- 88 vs -793 +/- 175, mm Hg/h (p = 0.001). The cumulative mean arterial BP deficit for survivors was -10 +/- 13 mm Hg/h, and for nonsurvivors it was -57 +/- 24 mm Hg/h (p = 0.078).

CONCLUSIONS

Noninvasive monitoring systems provided continuously monitored on-line displays of data in the early postadmission period from the ED to the operating room and to the ICU for early recognition of circulatory dysfunction in short-term emergency conditions. Survival was predicted by discriminant analysis models based on the quantitative assessment of the net cumulative deficits of CI, arterial hypoxemia, and tissue perfusion, which were significantly greater in the nonsurvivors.

Effects of maximizing oxygen delivery on morbidity and mortality in high-risk surgical patients

OBJECTIVE

To evaluate the effects of maximizing the oxygen delivery on morbidity and mortality in patients >60 yrs of age and/or with chronic diseases of vital organs who underwent major elective surgery.

DESIGN

Prospective, randomized, controlled trial.

SETTING

A 24-bed general intensive care unit of a teaching hospital.

PATIENTS

Thirty-seven high-risk patients who underwent major surgery.

INTERVENTIONS

The hemodynamic and oxygen transport variables and outcomes in 18 patients (control group) treated to maintain normal values of oxygen delivery were compared with 19 patients (protocol group) treated to maintain "supranormal" values. Therapy in both groups consisted of volume expansion and, when necessary, dobutamine to reach target values, during the surgery and 24 hrs postoperatively.

MEASUREMENTS AND MAIN RESULTS

We interrupted the study because of a significant difference in the 60-day mortality rate. The mortality rate in the control group was significantly higher when compared with the protocol group (9/18 [50%] vs. 3/19 [15.7%], p < .05). The prevalence of clinical and infectious complications was higher in the control group than in the protocol group (67% and 31% respectively; relative risk, 0.47; 95% confidence interval, 0.226-0.991; p < .05) and there was a trend toward more severe organ dysfunction in nonachievers patients (17/24 [71%] vs. 6/13 [46%], relative risk, 0.65; 95% confidence interval, 0.343-1.237; NS).

CONCLUSION

Older patients with existing cardiorespiratory illness undergoing major surgery have a reduced morbidity and mortality when dobutamine is used to maximize oxygen transport.

Endpoints of resuscitation of critically injured patients: normal or supranormal? A prospective randomized trial

OBJECTIVE

To evaluate the effect of early optimization in the survival of severely injured patients.

SUMMARY BACKGROUND DATA

It is unclear whether supranormal ("optimal") hemodynamic values should serve as endpoints of resuscitation or simply as markers of the physiologic reserve of critically injured patients. The failure of optimization to produce improved survival in some randomized controlled trials may be associated with delays in starting the attempt to reach optimal goals. There are limited controlled data on trauma patients.

METHODS

Seventy-five consecutive severely injured patients with shock resulting from bleeding and without major intracranial or spinal cord trauma were randomized to resuscitation, starting immediately after admission, to either normal values of systolic blood pressure, urine output, base deficit, hemoglobin, and cardiac index (control group, 35 patients) or optimal values (cardiac index >4.5 L/min/m2, ratio of transcutaneous oxygen tension to fractional inspired oxygen >200, oxygen delivery index >600 mL/min/m2, and oxygen consumption index >170 mL/min/m2; optimal group, 40 patients). Initial cardiac output monitoring was done noninvasively by bioimpedance and, subsequently, invasively by thermodilution. Crystalloids, colloids, blood, inotropes, and vasopressors were used by predetermined algorithms.

RESULTS

Optimal values were reached intentionally by 70% of the optimal patients and spontaneously by 40% of the control patients. There was no difference in rates of death (15% optimal vs. 11% control), organ failure, sepsis, or the length of intensive care unit or hospital stay between the two groups. Patients from both groups who achieved optimal values had better outcomes than patients who did not. The death rate was 0% among patients who achieved optimal values compared with 30% among patients who did not. Age younger than 40 years was the only independent predictive factor of the ability to reach optimal values.

CONCLUSIONS

Severely injured patients who can achieve optimal hemodynamic values are more likely to survive than those who cannot, regardless of the resuscitation technique. In this study, attempts at early optimization did not improve the outcome of the examined subgroup of severely injured patients.

The incidence of major morbidity in critically ill patients managed with pulmonary artery catheters: a meta-analysis

INTRODUCTION

The impact of pulmonary artery (PA) catheters on patient outcome has been questioned and their usage has become controversial. Meta-analysis on mortality has shown a trend for improved survival with PA catheter-guided therapy. We now perform a meta-analysis on morbidity from PA catheters in the published literature.

METHODS

We did a search of the medical database (Medline) from 1970 through 1996, using the headings "pulmonary artery catheterization," "Swan-Ganz catheterization" and "right heart catheterization," and restricting the results to "effectiveness" and "usefulness." We also consulted with other experts regarding published randomized controlled trials (RCTs). This yielded 16 RCTs addressing the question of effectiveness of PA catheter-guided treatment. Of these, 12 were found to include data on morbidity. Major morbidity, defined as organ failures as per the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference criteria, from these trials was entered into a formal meta-analysis.

RESULTS

A total of 1,610 patients from the 12 trials were analyzed. Morbidity events were observed in 62.77% of the PA catheter treatment group, and in 74.34% of the control group. A relative risk ratio of 0.78074 was obtained, with a 95% confidence interval of 0.6459-0.94374 and a corresponding p of .0168, a lower morbidity in the PA catheter treatment group. Those with PA catheter-guided treatment had a mean protective effect of 21.9% for risk of morbidity. Other important covariates such as acuity of illness, quality score of trials, year of publication, type of PA catheter-guided treatment used (PA catheter vs. no PA catheter, or PA catheter vs. PA catheter for supranormal hemodynamic values), and surgical or mixed patient population, all increased variability and were not statistically significant predictors for risk ratio of morbidity.

CONCLUSIONS

Meta-analysis of RCTs included in this study shows that there is a statistically significant reduction in morbidity using PA catheter-guided strategies.

Oxygen consumption in the early postinjury period: use of continuous, on-line indirect calorimetry

OBJECTIVE

To determine the patterns of oxygen consumption (Vo2) using indirect calorimetry (IC) for the first 24 hrs after serious blunt traumatic injury.

DESIGN

Prospective, observational study.

SETTING

Surgical intensive care unit of a Level 1 trauma center.

PATIENTS

Sixty-six mechanically ventilated patients with blunt traumatic injury and Injury Severity Score >15.

INTERVENTIONS

IC for 24 hrs postinjury. Patients were resuscitated to standard parameters of perfusion.

MEASUREMENTS AND MAIN RESULTS

Mean patient age was 50.1+/-18.7 yrs with a mean Injury Severity Score 30.7+/-11.3). Mean Vo2 for all patients for the 24-hr study period was 168.5+/-29.5 mL/min/m2. The level of Vo2 was not related to Injury Severity Score, the number or combination of organ systems injured, or to the use of vasoactive agents. Patients >65 yrs of age had significantly lower Vo2 (P = .0038) compared with patients < or =50 yrs. Vo2 did not change over time after resuscitation to normal parameters of perfusion. Mean Vo2 was 156.5+/-63.2 mL/min/m2 in patients who developed multiple organ dysfunction, and 172.4+/-33.3 mL/min/m2 in those who did not develop multiple organ dysfunction (p = .16).

CONCLUSIONS

Seriously injured patients are hypermetabolic in the early postinjury period. The level of Vo2 is unrelated to injury severity or number of organ systems involved. Elderly patients can be expected to have lower levels of Vo2. Vo2 does not change significantly in response to resuscitation to normal parameters of perfusion. Vo2 measured by IC did not predict the development of multiple organ dysfunction.

Anemia in the patient undergoing surgery and the transfusion decision. A review

The heightened awareness of the problems of transfusion reactions, disease transmission, and potential immunosuppression has led surgeons to reevaluate their reasons for transfusion. Current practice policies recommend that elective transfusion of allogeneic blood be avoided whenever possible in patients having surgery. If patients are to have appropriate transfusion, the basic pathophysiology and clinical response of the patient to anemia must be understood. This article reviews the physiologic response to anemia in the patient having surgery and explores the components of the decision to use transfusion.

Benefits, risks and alternatives of pulmonary artery catheterization

Twenty-five years after the introduction of the pulmonary artery catheter in clinical practice, its effectiveness in improving patient outcome is seriously questioned. Experts still recommend to use pulmonary artery catheters in selected critically ill patients, although evidence supporting these recommendations is lacking. The risks and the unclear benefits associated with this procedure should prompt the search for alternative, noninvasive monitoring techniques.

Relationship of mortality to increasing oxygen delivery in patients > or = 50 years of age: a prospective, randomized trial

OBJECTIVE

To investigate the relationship of mortality to early resuscitation using two levels of oxygen delivery (DO2) in critically ill surgical patients > or =50 yrs of age who were stratified into groups: age < or =75 yrs (age 50 to 75 yrs group); and age >75 yrs (age >75 yrs group).

DESIGN

A prospective, randomized trial, continued from a previous project.

SETTING

Surgical intensive care unit, university affiliated.

PATIENTS

Consecutive patients, >50 yrs of age, unable to generate a DO2 of > or =600 mL/min/m2 with fluid resuscitation alone, with a diagnosis of systemic inflammatory response syndrome, sepsis, severe sepsis, septic shock, and/or acute respiratory distress syndrome.

INTERVENTIONS

During the first 24 hrs of resuscitation, patients were randomized to receive fluids, blood transfusions, and vasoactive agents in order to achieve DO2 treatment goals of > or =600 mL/ min/m2 in the protocol group and 450 to 550 mL/min/m2 in the control group.

MEASUREMENTS AND MAIN RESULTS

One hundred five patients completed the study. In patients aged 50 to 75 yrs, the mortality rate was 21% (9/43) in the protocol group and 52% (12/23) in the control group (p=.01, 95% confidence interval of -58% to -4%). In patients >75 yrs of age, the mortality rate was 57% (12/21) in the protocol group and 61% (11/18) in the control group. Oxygen extraction ratios (O2ER) and oxygen consumption values were significantly (p=.02) lower in the age >75 yrs group compared with the age 50 to 75 yrs group.

CONCLUSIONS

Patients 50 to 75 yrs of age receiving a DO2 of > or =600 mL/min/m2 demonstrated a statistically significant (p=.01) improved survival rate over patients in the control group. Patients >75 yrs of age demonstrated no benefit from attempts to increase DO2 to >600 mL/min/m2, and they may have been overtreated as reflected by the lower O2ER values in this age group. Treating to an O2ER that reflects a balance between oxygen consumption and DO2 may be an alternative goal that allows individual titration.

Oxygen delivery is an important predictor of outcome in patients with ruptured abdominal aortic aneurysms

OBJECTIVE

The purpose of this study was to evaluate the relation of oxygen delivery (DO2) to the occurrence of multiple organ dysfunction (MOD) in patients with ruptured abdominal aortic aneurysms (AAA).

SUMMARY BACKGROUND DATA

Patients with ruptured AAA are at high risk for the development of MOD and death. Previous reports of high-risk general surgical patients have shown improved survival when higher levels of DO2 are achieved.

METHODS

Hemodynamic data were collected at 4-hour intervals on 57 consecutive patients (mean age, 70.5 years) who survived 24 hours after repair of infrarenal ruptured AAA. Patients were resuscitated to standard parameters of perfusion (pulse, blood pressure, urine output, normal base deficit). MOD was determined based on six organ systems. Standard parametric (analysis of variance, t tests) and nonparametric (chi square, Wilcoxon) tests were used to compare hemodynamic data, red blood cell requirements, colon ischemia, and organ failure for patients with and without MOD.

RESULTS

Patients who developed MOD had a significantly lower cardiac index and DO2 for the first 12 hours; the difference was most significant at 8 hours. Logistic regression analysis demonstrated that the strongest predictors of MOD were DO2, early onset of renal failure, and total number of red blood cells transfused.

CONCLUSIONS

DO2 is an earlier and better predictor of MOD after ruptured AAA than previously identified risk factors. Failure to achieve a normal DO2 in the first 8 hours after repair is strongly associated with the development of MOD and a high mortality. Strategies to restore normal DO2 may be useful to improve outcome in these high-risk patients.

Therapy of patients with head injuries: key parameters for management

BACKGROUND

Secondary brain injury, presumed secondary to ischemia, increases the mortality and morbidity of traumatic brain injury. Although many mechanisms appear to be involved, many potential ischemic insults results from changes in readily observable physiologic variables.

METHODS

A focused search of scientific articles published in English to determine what data are available to suggest parameters within which key physiologic variables should be maintained.

RESULTS

Few data demonstrate that maintenance of variables within specific ranges alters outcome; however, considerable evidence establishes association with poor outcome and hypotension, intracranial hypertension, and cerebral venous saturation. Key parameters vary somewhat based upon the phase of treatment after injury. Other variables, such as systemic oxygen delivery and brain saturation measured by near-infrared spectroscopy, are less well linked to outcome.

CONCLUSIONS

Further research is necessary to establish that manipulation of physiologic variables to maintain them within preset ranges improves outcome.

Pulmonary artery catheters in the critically ill. An overview using the methodology of evidence-based medicine

Evidence-based approaches to assessing the clinical literature are used increasingly in issues relating to critical care medicine. As we discussed previously, this approach attempts to provide a logical and convenient framework from which the quality and relevance of clinical studies may be assessed in an unbiased manner. An evidence-based approach also allows the reader to differentiate between solid evidence and evidence that is based on a presumed mechanism, standard practice, or conventional wisdom. Evidence-based medicine that deemphasizes intuition, unsystemic clinical experience, and pathophysiologic rationale is sufficient grounds for clinical decision making and stresses the examination of evidence from clinical research. Importantly, it is the objective nature by which the evidence-based medicine paradigm approaches the questions of "What are we doing" and "How can we do better," that causes health care providers and funding agencies to increasingly adopt this paradigm as a primary principle. The role of evidence-based medicine, therefore, is not to discount expert opinion but, wherever possible, to require that recommendations be based on the results of rigorous and controlled scientific study. We introduced this article by highlighting the growing imbalance between resources and patient needs in the critical care environment. At the level of diagnostic technology and therapeutic care plans, critical care professionals increasingly are asked to identify strategies to improve efficiencies-approaches with rigorous costs that at the same time promote better patient care. Formalized technology assessment is one of the mechanisms to accomplish this. Using critical appraisal within the context of evidence-based medicine is one of the mechanisms by which data can be synthesized to describe technology assessment. In this example, we used controversies surrounding use of pulmonary artery catheterization in critically ill patients to highlight some of the principles of evidence-based medicine at the bedside. We introduced how a particular case example can be used to ask the question, "What is the evidence that a particular diagnostic technology or therapeutic modality improves outcome?" In the case of PACs, no one would argue that a diagnostic technology a priori leads to improved outcome; rather, we have to presume that given good data, the care provider will apply the most appropriate management strategy. In this case example, however, we demonstrate how the critical appraisal process should identify a search strategy to find the most appropriate evidence to support the questioning process. From this, the evidence can be critically appraised and tabulated. In the case of the PAC, Table 13 demonstrates that there are few data to identify a grade A recommendation that the PAC should be used as part of the care process in critically ill patients. Finding that there is little evidence to support the use of pulmonary artery catheterization in the clinical literature does not mean that this diagnostic technology is neither efficacious nor effective. It might well be that information provided by PACs is important in the care process. However, what this exercise has taught us is that there is little objective evidence to support this conclusion. The challenge to critical care practitioners is not only to apply the evidence-based processes more frequently to our environment but also to use the information to separate out clearly what is fact versus opinion. Where there is little evidence to support a particular clinical practice, as we have demonstrated with the PAC review earlier, the challenge to the clinician should be the design and conduct of clinical trials clarifying debate between opinion and evidence.

The use of oxygen consumption and delivery as endpoints for resuscitation in critically ill patients

OBJECTIVE

Oxygen consumption (VO2I) and delivery (DO2I) indices have been stated to be superior to conventional parameters as endpoints for resuscitation. However, another interpretation of published data is that inability to increase VO2I/DO2I given adequate volume resuscitation reflects inadequate physiologic reserve and poor outcome.

DESIGN

Fifty-eight critically ill patients were randomized to two groups. In group 1 (27 patients) attempts were made to maintain VO2I > or = 150 or DO2I > or = 600 mL/min/m2. If DO2I was > 600, no attempt was made to increase VO2I even if it was < 150. Group 2 (31 patients) was resuscitated based on conventional parameters. Volume resuscitation protocols and goals for pulmonary capillary wedge pressure were the same in both groups. VO2I/DO2I were recorded in group 2, but physicians were blinded to this data. Age, Injury Severity Score, and Acute Physiology and Chronic Health Evaluation (APACHE II) score were not different between groups.

MAIN RESULTS

Three patients in group 1 and two patients in group 2 died of organ failure (OF). One additional patient in group 2 died of refractory shock within 24 hours. Two of the patients in group 1 who died failed to meet VO2I/DO2I goals within 24 hours despite maximal resuscitation. Mortality was not different between the groups even with exclusion of the group 1 patients who failed to meet VO2I/DO2I goals (p = 0.66). After exclusion of the patient in group 2 who died of refractory shock, OF occurred in 18 of 27 (67%) in group 1 and in 22 of 30 (73%) in group 2 (p = 0.58). Length of ventilator support, intensive care unit stay, and hospital stay were not different between groups. When all patients were assessed, no difference was found in the incidence of OF between patients who attained the VO2I goal and those who did not. OF occurred in 20 of 34 (59%) patients who maintained a mean DO2I > or = 600 during the first 24 hours of the study and in 21 of 24 (88%) of those who did not (p < 0.02).

CONCLUSIONS

No difference was found in the incidence of OF or death in patients resuscitated based on oxygen transport parameters compared to conventional parameters. These data suggest that given adequate volume resuscitation, oxygen-based parameters are more useful as predictors of outcome than as endpoints for resuscitation.

Does increasing oxygen delivery improve outcome in the critically ill? No

The strategy of treating critically ill patients by increasing oxygen delivery and consumption to values previously observed among survivors of critical illness (supranormal values) is based on the belief that (1) tissue hypoxia may persist in critically ill patients despite aggressive early resuscitation to traditional endpoints of adequate tissue perfusion and (2) that increasing oxygen delivery can reverse tissue hypoxia. This article addresses the question of whether increasing oxygen delivery improves outcomes in critically ill patients by reviewing the relationship between whole-body oxygen delivery and consumption and by critically examining the randomized controlled trials that have increased oxygen delivery to supranormal values.

Current concepts of sepsis and acute lung injury

Acute respiratory distress syndrome continues to be a vexing clinical problem with no specific therapy. Epidemiologic and basic sciences have advanced our understanding of the clinical syndrome and have brought us to the brink of effective intervention strategies. This article carefully examines the current state of knowledge, with reference to acute lung injury and current efforts, to arrive at effective pharmacologic approaches.