Acute physiology and chronic health evaluation II score is a better predictor of mortality than IBMP-10 in patients with ventilator-associated pneumonia

BACKGROUND

The (Immunodeficiency, Blood pressure [<90 mm Hg], Multilobular intiltrates [chest x-ray], Platelets [<100×10⁹/L], hospitalization [<10 days] before the onset of ventilator-associated pneumonia [VAP]) IBMP-10 is a new scoring system proposed as an easy-to-use alternative to the Acute Physiology and Chronic Health Evaluation II (APACHE II) score for predicting mortality in patients with ventilator-associated pneumonia (VAP). The objective of this study was to determine the validity of the IBMP-10 score compared with APACHE II in predicting mortality for an independent population consisting predominantly of surgical and neurotrauma patients.

METHODS

The IBMP-10 and APACHE II scores on the day of VAP diagnosis were calculated, and areas under the receiver-operating characteristic curves (AUROCs) were compared to determine the tests' abilities to predict 14- and 28-day mortality.

RESULTS

A total of 168 patients meeting the radiologic and clinical criteria for VAP for a single hospitalization between 2004 and 2007 were included; 80% of these were from the surgical or neurotrauma intensive care unit. Overall mortality rates were 15% and 23% at 14 and 28 days, respectively. The AUROC for the IMBP-10 score for predicting 14-day mortality was 0.609 (p=0.084) compared with 0.648 (p=0.017) for the APACHE II score. Both IBMP-10 and APACHE II AUROCs for predicting 14-day mortality were lower than observed in the original score validation (0.808 and 0.743, respectively). The AUROCs for predicting 28-day mortality were 0.602 (p=0.056) and 0.705 (p<0.001) for IBMP10 and APACHE II, respectively.

CONCLUSIONS

The IBMP-10 score was less reliable than the APACHE II score in predicting 14-day mortality in this independent population of VAP patients. This finding highlights the need for additional validation of new disease severity scoring systems in a study population independent of the population used to derive score criteria, as well as in more specific populations of critically ill patients.

Pancreatic stone protein: a marker of organ failure and outcome in ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common hospital-acquired, life-threatening infection. Poor outcome and health-care costs of nosocomial pneumonia remain a global burden. Currently, physicians rely on their experience to discriminate patients with good and poor outcome. However, standardized prognostic measures might guide medical decisions in the future. Pancreatic stone protein (PSP)/regenerating protein (reg) is associated with inflammation, infection, and other disease-related stimuli. The prognostic value of PSP/reg among critically ill patients is unknown. The aim of this pilot study was to evaluate PSP/reg in VAP.

METHODS

One hundred one patients with clinically diagnosed VAP were assessed. PSP/reg was retrospectively analyzed using deep-frozen serum samples from VAP onset up to day 7. The main end point was death within 28 days after VAP onset.

RESULTS

Serum PSP/reg was associated with the sequential organ failure assessment score from VAP onset (Spearman rank correlation coefficient 0.49 P < .001) up to day 7. PSP/reg levels at VAP onset were elevated in nonsurvivors (n = 20) as compared with survivors (117.0 ng/mL [36.1-295.3] vs 36.3 ng/mL [21.0-124.0] P = .011). The areas under the receiver operating characteristic curves of PSP/reg to predict mortality/survival were 0.69 at VAP onset and 0.76 at day 7. Two PSP/reg cutoffs potentially allow for identification of individuals with a particularly good and poor outcome. Whereas PSP/reg levels below 24 ng/mL at VAP onset were associated with a good chance of survival, levels above 177 ng/mL at day 7 were present in patients with a very poor outcome.

CONCLUSIONS

Serum PSP/reg is a biomarker related to organ failure and outcome in patients with VAP.

TRIAL REGISTRY

ISRCTN.org; No.: ISRCTN61015974; URL: www.isrctn.org.

Severity of ICU-acquired pneumonia according to infectious microorganisms

PURPOSE

To assess the severity of intensive care unit (ICU)-acquired pneumonia (ICUAP) according to the bacteria involved, classified into seven groups: third-generation cephalosporin-resistant non-fermenting Gram-negative bacilli (resistant C3NF); sensitive C3NF; methicillin-resistant Staphylococcus aureus; methicillin-sensitive Staphylococcus aureus; extended-spectrum beta-lactamase-producing Enterobacteriaceae; Enterobacteriaceae not producing extended-spectrum beta-lactamase; Haemophilus influenzae and Streptococcus pneumoniae.

METHODS

Over a 4-year period, sequential organ failure assessment (SOFA) score was prospectively measured daily in 453 adult patients with ICUAP. ICUAP severity was evaluated by the severity of sepsis and by the occurrence of new organ dysfunctions or failures (OD/F) during ICUAP.

RESULTS

Septic shock occurred in 21% of all cases of ICUAP. The occurrence of new OD/F during ICUAP was similar regardless of the identified microorganism. These new OD/F represented less than 11% of SOFAmax, defined as the sum of all OD/F occurring at any time during the ICU stay. There was a significant association between SOFApreICUAP, defined as the sum of all the OD/F occurring before ICUAP, and ICUAP severity. In the multivariate analysis, the type of bacteria was not a risk factor (RF) for occurrence of septic shock and mortality. Age and SOFApreICUAP were RF for the sepsis severity. The ICUAP severity was an RF for ICU mortality.

CONCLUSIONS

ICUAP was responsible for a minor proportion of OD/F occurring during the ICU stay. Severity of ICUAP was related to clinical status prior to ICUAP, but not to the type of bacteria. ICU mortality depended on the severity of ICUAP.

The impact of COPD on ICU mortality in patients with ventilator-associated pneumonia

OBJECTIVE

To determine the impact of COPD on intensive care unit (ICU) mortality in patients with VAP.

METHODS

This prospective observational study was performed in a mixed ICU during a 3-year period. Eligible patients received mechanical ventilation for >48 h and met criteria for microbiologically confirmed VAP. Risk factors for ICU mortality were determined using univariate and multivariable analyses.

RESULTS

Two hundred and fifteen patients with microbiologically confirmed VAP were included. Most VAP episodes were late-onset (88%), and Pseudomonas aeruginosa was the most frequently isolated bacterium (39% of VAP episodes). ICU mortality was significantly lower in non-COPD patients (n = 150) compared to COPD patients (n = 65) (43.3% vs 60%, p = 0.027, OR [95% CI] = 1.96 [1.8-3.54]). Duration (days) of mechanical ventilation and ICU stay median (IQR) in non-COPD patients were 25 (15-42) and 30 (18-48), whereas in COPD patients were 31 (19-45) and 36 (20-48) (p > 0.05). The differences in duration (days) of mechanical ventilation and ICU stay were significant between non-COPD patients and severe COPD (GOLD stage IV) patients (p = 0.001 and p = 0.02, respectively). Multivariable analysis identified COPD [OR (95% CI) 2.58 (1.337-5)], SAPS II [1.024 (1.006-1.024)] and presence of shock at VAP diagnosis [3.72 (1.88-7.39)] as independent risk factors for ICU mortality.

CONCLUSION

COPD, SAPS II, and shock at VAP diagnosis are independently associated with ICU mortality in patients who present VAP.

Multinational, observational study of procalcitonin in ICU patients with pneumonia requiring mechanical ventilation: a multicenter observational study

Introduction

The intent of this study was to determine whether serum procalcitonin (PCT) levels are associated with prognosis, measured as organ dysfunctions and 28-day mortality, in patients with severe pneumonia.

Methods

This was a multicenter, observational study of critically ill adult patients with pneumonia requiring mechanical ventilation conducted in 10 academic hospitals in Canada, the United States, and Central Europe. PCT was measured daily for 14 days using an immuno-luminometric assay.

Results

We included 175 patients, 57 with community acquired pneumonia (CAP), 61 with ventilator associated pneumonia (VAP) and 57 with hospital acquired pneumonia (HAP). Initial PCT levels were higher in CAP than VAP patients (median (interquartile range: IQR); 2.4 (0.95 to 15.8) vs. 0.7 (0.3 to 2.15), ng/ml, P < 0.001) but not significantly different to HAP (2.2 (0.4 to 8.0) ng/ml). The 28-day ICU mortality rate for all patients was 18.3% with a median ICU length of stay of 16 days (range 1 to 142 days). PCT levels were higher in non-survivors than in survivors. Initial and maximum PCT levels correlated with maximum Sequential Organ Failure Assessment (SOFA) score r² = 0.50 (95% CI: 0.38 to 0.61) and r² = 0.57 (0.46 to 0.66), respectively. Receiver operating curve (ROC) analysis on discrimination of 28-day mortality showed areas under the curve (AUC) of 0.74, 0.70, and 0.69 for maximum PCT, initial PCT, and Acute Physiology and Chronic Health Evaluation (APACHE) II score, respectively. The optimal cut-off to predict mortality for initial PCT was 1.1 ng/ml (odds ratio: OD 7.0 (95% CI 2.6 to 25.2)) and that for maximum PCT was 7.8 ng/ml (odds ratio 5.7 (95% CI 2.5 to 13.1)).

Conclusions

PCT is associated with the severity of illness in patients with severe pneumonia and appears to be a prognostic marker of morbidity and mortality comparable to the APACHE II score.

Proof of principle: the predisposition, infection, response, organ failure sepsis staging system

OBJECTIVE

In an effort to improve upon the traditional sepsis syndrome definitions, the predisposition, infection, response, organ dysfunction (PIRO) model was proposed to better characterize sepsis. The objective of this investigation was to derive and validate a sepsis staging system based on the PIRO concept that risk stratifies patients with suspected infection.

DESIGN

Three independent, observational, prospective cohorts were studied. A derivation cohort (n = 2,132) was used to create the PIRO score, identifying independent predictors of mortality. Individual values were assigned to create the weighted integer score for each parameter, yielding the final PIRO score. The prognostic performance was then investigated in independent internal (n = 4,618) and external (n = 1,004) validation cohorts.

SETTING

Two large U.S. tertiary care centers.

PATIENTS

Patients admitted to the hospital from the emergency department with suspected infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The PIRO staging system was created by combining components of predisposition (age, chronic obstructive pulmonary disease, liver disease, nursing home residency, and malignancy with and without metastasis), infection (pneumonia and cellulitis), response (tachypnea, bandemia, and tachycardia), and organ dysfunction (renal, respiratory, cardiac, metabolic, and hematologic). The derived PIRO score showed stepwise increase in mortality with increasing points and high discriminatory ability with an area under the curve of 0.90 in the derivation cohort, 0.86 in internal validation, and 0.83 in external validation.

CONCLUSIONS

This study provides evidence-based support for the PIRO approach to sepsis staging. Future efforts may utilize this approach with additional parameters (e.g., genetics and novel biochemical markers) to develop further the PIRO stratification system.

Bacteremia is an independent risk factor for mortality in nosocomial pneumonia: a prospective and observational multicenter study

Introduction

Since positive blood cultures are uncommon in patients with nosocomial pneumonia (NP), the responsible pathogens are usually isolated from respiratory samples. Studies on bacteremia associated with hospital-acquired pneumonia (HAP) have reported fatality rates of up to 50%. The purpose of the study is to compare risk factors, pathogens and outcomes between bacteremic nosocomial pneumonia (B-NP) and nonbacteremic nosocomial pneumonia (NB-NP) episodes.

Methods

This is a prospective, observational and multicenter study (27 intensive care units in nine European countries). Consecutive patients requiring invasive mechanical ventilation for an admission diagnosis of pneumonia or on mechanical ventilation for > 48 hours irrespective of admission diagnosis were recruited.

Results

A total of 2,436 patients were evaluated; 689 intubated patients presented with NP, 224 of them developed HAP and 465 developed ventilation-acquired pneumonia. Blood samples were extracted in 479 (69.5%) patients, 70 (14.6%) being positive. B-NP patients had higher Simplified Acute Physiology Score (SAPS) II score (51.5 ± 19.8 vs. 46.6 ± 17.5, P = 0.03) and were more frequently medical patients (77.1% vs. 60.4%, P = 0.01). Mortality in the intensive care unit was higher in B-NP patients compared with NB-NP patients (57.1% vs. 33%, P < 0.001). B-NP patients had a more prolonged mean intensive care unit length of stay after pneumonia onset than NB-NP patients (28.5 ± 30.6 vs. 20.5 ± 17.1 days, P = 0.03). Logistic regression analysis confirmed that medical patients (odds ratio (OR) = 5.72, 95% confidence interval (CI) = 1.93 to 16.99, P = 0.002), methicillin-resistant Staphylococcus aureus (MRSA) etiology (OR = 3.42, 95% CI = 1.57 to 5.81, P = 0.01), Acinetobacter baumannii etiology (OR = 4.78, 95% CI = 2.46 to 9.29, P < 0.001) and days of mechanical ventilation (OR = 1.02, 95% CI = 1.01 to 1.03, P < 0.001) were independently associated with B-NP episodes. Bacteremia (OR = 2.01, 95% CI = 1.22 to 3.55, P = 0.008), diagnostic category (medical patients (OR = 3.71, 95% CI = 2.01 to 6.95, P = 0.02) and surgical patients (OR = 2.32, 95% CI = 1.10 to 4.97, P = 0.03)) and higher SAPS II score (OR = 1.02, 95% CI = 1.01 to 1.03, P = 0.008) were independent risk factors for mortality.

Conclusions

B-NP episodes are more frequent in patients with medical admission, MRSA and A. baumannii etiology and prolonged mechanical ventilation, and are independently associated with higher mortality rates.

A New Approach to Ventilator-associated Pneumonia Based on the PIRO System

Several new scoring systems have been developed over recent years to assess the degree of organ failure (e.g., Acute Physiology and Chronic Health Evaluation [APACHE] II, APACHE III, Sequential Organ Failure Assessment [SOFA], Simplified Acute Physiology Score [SAPS] II, and Multiple Organ Dysfunction Score [MODS]). Most of these were models generated based on the concepts of sepsis, severe sepsis and septic shock. In 2001, an International Sepsis Definition Conference updated these terms in order to facilitate standardized enrolment into clinical trials, but due to their simplicity and easy use physicians rapidly adopted them for daily clinical practice [1].

Prowess-shock trial: a protocol overview and perspectives

Sepsis remains a challenge for intensive care physicians, as it keeps up with high mortality rate in spite of the high costs associated with its treatment. Several studies indicate that the infusion of Drotrecogin-alpha activated (DrotAA) reduce mortality in patients at high risk of death when administered early and secured the appropriate initial treatment of sepsis as recommended by Surviving Sepsis Campaign. Europe and United States of America differ regarding the criteria of high risk of death in sepsis, two or more organ dysfunctions and Acute Physiology and Chronic Health Evaluation 25 or more, respectively. In addition to varied definitions of high risk of death for inclusion of patients in sepsis studies, the possibility of bleeding related to drug use and intrinsic limitations related to study design led the Company to develop a new randomized, multinational, placebo-controlled, double-blind study to assess the effectiveness of drug in patients with septic shock in adults.

Attributable mortality of ventilator-associated pneumonia: respective impact of main characteristics at ICU admission and VAP onset using conditional logistic regression and multi-state models

PURPOSE

Methods for estimating the excess mortality attributable to ventilator-associated pneumonia (VAP) should handle VAP as a time-dependent covariate, since the probability of experiencing VAP increases with the time on mechanical ventilation. VAP-attributable mortality (VAP-AM) varies with definitions, case-mix, causative microorganisms, and treatment adequacy. Our objectives here were to compare VAP-AM estimates obtained using a traditional cohort analysis, a multistate progressive disability model, and a matched-cohort analysis; and to compare VAP-AM estimates according to VAP characteristics.

METHODS

We used data from 2,873 mechanically ventilated patients in the Outcomerea database. Among these patients from 12 intensive care units, 434 (15.1%) experienced VAP; of the remaining patients, 1,969 (68.5%) were discharged alive and 470 (16.4%) died. With the multistate model, VAP-AM was 8.1% (95% confidence interval [95%CI], 3.1-13.1%) for 120 days' complete observation, compared to 10.4% (5.6-24.5%) using a matched-cohort approach (2,769 patients) with matching on mechanical ventilation duration followed by conditional logistic regression. VAP-AM was higher in surgical patients and patients with intermediate (but not high) Simplified Acute Physiologic Score II values at ICU admission. VAP-AM was significantly influenced by time to VAP but not by resistance of causative microorganisms. Higher Logistic Organ Dysfunction score at VAP onset dramatically increased VAP-AM (to 31.9% in patients with scores above 7).

CONCLUSION

A multistate model that appropriately handled VAP as a time-dependent event produced lower VAP-AM values than conditional logistic regression. VAP-AM varied widely with case-mix. Disease severity at VAP onset markedly influenced VAP-AM; this may contribute to the variability of previous estimates.

PIRO: The Key to Success?

Sepsis continues to represent a major problem in intensive care units worldwide. Diagnosis and management are often complex due in part to the remarkably diverse nature of the septic patient. Indeed, sepsis can range in severity from mild systemic inflammation of little clinical importance through to a widespread severe inflammatory response with multiple organ failure and a mortality rate in excess of 50%. Sepsis can affect individuals of any age group, with no or multiple co-morbidities, and with many different ongoing diagnoses. It can occur as the result of infection by one or more of a multitude of microbial pathogens impacting on any of numerous different sites within the body. Given the huge complexity of sepsis and the diverse populations of patients it affects, simple definitions are of relatively little use and a more detailed framework which can be used to better characterize patients with sepsis has been proposed, much as the TNM classification (tumor size, nodal spread, metastases) has been successfully used in clinical oncology. In this chapter, we discuss the development of this PIRO system, and suggest how it may be used in the future to aid diagnosis, guide therapy, and improve prognostication.