Determinants of immediate survival among chronic respiratory insufficiency patients admitted to an intensive care unit for acute respiratory failure. A prospective multicenter study. The French Task Group for Acute Respiratory Failure in Chronic Respiratory insufficiency

The Glasgow prognostic score can be a predictor of mortality in acute exacerbation of chronic obstructive pulmonary disease

Aim: To determine the prognostic value of Glasgow Prognostic Score (GPS) in acute exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD) requiring hospitalization.Methods: Hospital electronic database of 129 patients with AECOPD was retrospectively searched and CRP levels, complete blood count, arterial blood gas (ABG) values and pulmonary function test (PFT) parameters of patients were recorded. Hospital mortality and need for ICU transfer were determined as adverse outcomes from files of cases.Results: 106 of 129 patients were male (82.2%) and rest of them were female (17.8%). GPS 0 was not observed in any patient, GPS 1 was observed in 101 patients, and GPS 2 was observed in 28 patients. The rate of adverse outcomes (ICU/Ex) was significantly increased in the GPS 2 group when compared to the GPS 1 group (X²:7.631, p < 0.01). Logistic regression analysis indicated that pH≤7.35 (p < 0.05, OR: 5.65, CI: 1.35-23.58%) and GPS 2 score (p < 0.05, OR: 5.52, CI: 1.45-20.97%) were independent predictors for adverse outcomes for AECOPD.Conclusion: Our results demonstrate that the GPS may have predictive value for adverse outcomes in patients with AECOPD.

The prognostic variables predictive of mortality in patients with an exacerbation of COPD admitted to the ICU: an integrative review

INTRODUCTION

Chronic Obstructive Pulmonary Disease (COPD) frequently presents with an acute exacerbation (AECOPD). Debate exists as to whether these patients should be admitted to intensive care units (ICUs). An integrative review was performed to determine whether clinical variables available at the time of ICU admission are predictive of the intermediate-term mortality of patients with an AECOPD.

METHODS

An integrative review was structured to incorporate a five-stage review framework to facilitate data extraction, analysis and presentation. The quality of the studies contributing to the integrative review was assessed with a novel scoring system developed from previously published data and adapted to this setting.

RESULTS

The integrative review search strategy identified 28 studies assessing prognostic variables in this setting. Prognostic variables associated with intermediate-term mortality were low Glasgow Coma Scale (GCS) on admission to ICU, cardio-respiratory arrest prior to ICU admission, cardiac dysrhythmia prior to ICU admission, length of hospital stay prior to ICU admission and higher values of acute physiology scoring systems. Premorbid variables such as age, functional capacity, pulmonary function tests, prior hospital or ICU admissions, body mass index and long-term oxygen therapy were not found to be associated with intermediate-term mortality nor was the diagnosis attributed to the cause of the AECOPD.

DISCUSSION

Variables associated with intermediate-term mortality after AECOPD requiring ICU admission are those variables, which reflect underlying severity of acute illness. Premorbid and diagnostic data have not been shown to be predictive of outcome. A scoring system is proposed to assess studies of prognosis in AECOPD.

Is there a role for mask continuous positive airway pressure in acute respiratory failure due to COPD? Lessons from a retrospective audit of 3 different cohorts

Exacerbations of COPD that result in acute respiratory failure requiring intubation and mechanical ventilation have high morbidity and mortality. This study is a retrospective observational study that compared the outcomes of 237 patients with COPD and acute respiratory failure requiring intensive care unit (ICU) admission according to modality of initial therapy: mask continuous positive airway pressure (CPAP), medical therapy, or intubation. Of the patients treated with CPAP initially, only 16% failed and required intubation compared with 62% of those treated medically (p=0.001). The median length of ICU stay was 5 days in those treated with CPAP, compared with 7 days for those medically treated, and 8.5 days for intubated patients (p=0.001). When compared with mask CPAP, and after adjusting for potentially confounding differences, mortality was significantly higher if patients were initially intubated (adjusted odds ratios [OR] 15.7; 95% confidence interval [CI] 4.2, 59) or given medical therapy (OR 5.1; CI 1.2, 20.8). In COPD patients with acute respiratory failure, initial treatment with mask CPAP was associated with significantly better outcomes than other treatment modalities, even after adjusting for potentially confounding differences in disease severity.

Determinants of prolonged mechanical ventilation in patients with chronic obstructive pulmonary diseases and acute hypercapnic respiratory failure

BACKGROUND

The aim of the present study was to identify early risk factors for prolonged mechanical ventilation (PMV) in chronic obstructive pulmonary disease (COPD) patients admitted to respiratory intensive care units (RICU) for acute hypercapnic respiratory failure.

METHODS

PMV was defined as invasive ventilation lasting longer than 7 days. Between January 1, 2000 and December 31, 2005, epidemiological and clinical data on RICU admission day were retrospectively analyzed for eligible patients. Univariate and multiple stepwise logistic regression analyses were used for statistical analysis.

RESULTS

A total of 152 patients were eligible for evaluation during the 6-year study period and their mean age was 63+/-12 years. Fifty-one patients died before day 7 after the onset of MV (early death group). Of the remaining 101 patients who survived until day 7, 56 had been weaned successfully (non-PMV group) and 45 continued to receive MV (PMV group). Logistic regression analysis showed that age above 65 (OR=1.98, 95% CI=0.96-4.17, P=0.011), a pH of 7.30 or less measured 12 h after ventilation (OR=2.09, 95% CI=1.17-5.64, P=0.002), an APACHE II score above 20 (OR=3.25, 95% CI=1.58-7.10, P<0.001), development of non-respiratory organ failure (OR=4.67, 95% CI=1.54-9.71, P<0.001), and the presence of shock (OR=4.71, 95% CI=2.14-10.09, P<0.001) were independently associated with PMV. The presence of two factors predicted PMV with a sensitivity of 86% and a specificity of 94%.

CONCLUSION

Age, APACHE II score, refractory acidosis, presence of non-respiratory organ failure, and shock on RICU admission day were early determinants of PMV in patients with COPD and acute hypercapnic respiratory failure.

Canadian Thoracic Society recommendations for management of chronic obstructive pulmonary disease - 2007 update

Chronic obstructive pulmonary disease (COPD) is a major respiratory illness in Canada that is both preventable and treatable. Our understanding of the pathophysiology of this complex condition continues to grow and our ability to offer effective treatment to those who suffer from it has improved considerably. The purpose of the present educational initiative of the Canadian Thoracic Society (CTS) is to provide up to date information on new developments in the field so that patients with this condition will receive optimal care that is firmly based on scientific evidence. Since the previous CTS management recommendations were published in 2003, a wealth of new scientific information has become available. The implications of this new knowledge with respect to optimal clinical care have been carefully considered by the CTS Panel and the conclusions are presented in the current document. Highlights of this update include new epidemiological information on mortality and prevalence of COPD, which charts its emergence as a major health problem for women; a new section on common comorbidities in COPD; an increased emphasis on the meaningful benefits of combined pharmacological and nonpharmacological therapies; and a new discussion on the prevention of acute exacerbations. A revised stratification system for severity of airway obstruction is proposed, together with other suggestions on how best to clinically evaluate individual patients with this complex disease. The results of the largest randomized clinical trial ever undertaken in COPD have recently been published, enabling the Panel to make evidence-based recommendations on the role of modern pharmacotherapy. The Panel hopes that these new practice guidelines, which reflect a rigorous analysis of the recent literature, will assist caregivers in the diagnosis and management of this common condition.

Multiple-drug-resistant bacteria in patients with severe acute exacerbation of chronic obstructive pulmonary disease: Prevalence, risk factors, and outcome

OBJECTIVE

To determine prevalence, risk factors, and effect on outcome of multiple-drug-resistant (MDR) bacteria in patients with severe acute exacerbation of chronic obstructive pulmonary disease.

DESIGN

Prospective, observational, cohort study.

SETTING

Thirty-bed medical intensive care unit (ICU) in a university hospital.

METHODS

All chronic obstructive pulmonary disease patients with acute exacerbation who required intubation and mechanical ventilation for >48 hrs were eligible during a 4-yr period. Patients with pneumonia or other causes of acute respiratory failure were not eligible. In all patients, quantitative tracheal aspirate was performed at ICU admission (positive at 10 colony-forming units [cfu]/mL). MDR bacteria were defined as methicillin-resistant Staphylococcus aureus, ceftazidime- or imipenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and extended-spectrum beta-lactamase-producing Gram-negative bacilli. All patients received empirical antibiotic treatment at ICU admission. Univariate and multivariate analyses were used to determine variables associated with MDR bacteria and variables associated with ICU mortality.

RESULTS

A total of 857 patients were included, and 304 bacteria were isolated (>/=10 cfu/mL) in 260 patients (30%), including 75 MDR bacteria (24%) in 69 patients (8%). When patients with MDR bacteria were compared with patients without MDR bacteria, previous antimicrobial treatment (odds ratio [OR], 2.4; 95% confidence interval [95% CI], 1.2-4.7; p = .013) and previous intubation (OR, 31; 95% CI, 12-82; p < .001) were independently associated with MDR bacteria. When patients with bacteria other than MDR or patients with no bacteria were used as a reference group, these risk factors were still independently associated with MDR bacteria. Although ICU mortality rate was higher in patients with MDR bacteria than in patients without MDR bacteria (44% vs. 25%; p = .001; OR, 2.3; 95% CI, 1.4-3.8), MDR bacteria were not independently associated with ICU mortality. Inappropriate initial antibiotic treatment (88% vs. 5%; p = <.001; OR, 6.7; 95% CI, 3.8-12) and ventilator-associated pneumonia (23% vs. 5%; p = <.001; OR, 1.3; 95% CI, 1-1.8) rates were significantly higher in patients with MDR bacteria than in patients with bacteria other than MDR. Inappropriate initial antibiotic treatment was independently associated with increased ICU mortality (OR, 7.1; 95% CI, 1.9-30; p = .003).

CONCLUSION

MDR bacteria are common in patients with acute exacerbation of chronic obstructive pulmonary disease requiring intubation and mechanical ventilation. Previous antimicrobial treatment and previous intubation are independent risk factors for MDR bacteria. Although MDR bacteria are not independently associated with ICU mortality, inappropriate initial antibiotic treatment is an independent risk factor for ICU mortality in these patients. Further studies are needed to determine whether broad-spectrum antibiotic treatment is cost-effective in these patients.

Clinical presentation and predictors of outcome in patients with severe acute exacerbation of chronic obstructive pulmonary disease requiring admission to intensive care unit

BACKGROUND

Severe acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) is a common reason for emergency room (ER) visit about which little has been documented from India.

METHODS

Prospective study of the clinical presentation and predictors of outcome in 116 patients presenting with severe AE-COPD requiring admission to the medical intensive care unit between January 2000 and December 2004.

RESULTS

Their mean age was 62.1 +/- 9.8 years. There were 102 males. Mean duration of COPD was 7.2 +/- 5.8 years. All males were smokers (22.3 +/- 11.2 pack years); 35.2% smoked cigarettes and 64.8% smoked bidis. All women were exposed to domestic fuel. Associated co-morbid illnesses were present in 81 patients (69.8%); 53(45.7%) had one co-morbid illness and the remaining 28 (54.3%) had two or more co-morbid illnesses. Evidence of past pulmonary tuberculosis (PTB) was present in 28.4% patients; 5 patients who also had type II diabetes mellitus had active PTB. Arterial blood gas analysis revealed respiratory failure in 40 (33.8%) patients (type I 17.5% and type II 82.5%). Invasive mechanical ventilation was required in 18 patients. Sixteen (13.7%) patients died. Stepwise multivariate logistic regression analysis revealed need for invasive ventilation (OR 45.809, 95% CI 607.46 to 3.009;p < 0.001); presence of co-morbid illness (OR 0.126, 95% CI 0.428 to 0.037;p < 0.01) and hypercapnia (OR 0.114, 95% CI 1.324 to 0.010;p < 0.05) were predictors of death.

CONCLUSION

Co-morbid conditions and metabolic abnormalities render the diagnosis of AE-COPD difficult and also contribute to mortality. High prevalence of past PTB and active PTB in patients with AE-COPD suggests an intriguing relationship between smoking, PTB and COPD which merits further study.

Predictors of hospital outcome and intubation in COPD patients admitted to the respiratory ICU for acute hypercapnic respiratory failure

BACKGROUND

Mortality rate, the possible factors affecting mortality and intubation in patients with acute exacerbation of chronic obstructive pulmonary diseases (COPD) and hypercapnic respiratory failure (RF) are yet unclear.

OBJECTIVE

To identify the possible factors affecting mortality and intubation in COPD patients.

DESIGN

A prospective study using data obtained over the first 24h of respiratory intensive care unit (RICU) admission. Consecutive admissions of 656 patients were monitored and 151 of them who had acute exacerbation of COPD and hypercapnic RF were enrolled.

SETTING

University hospital, Department of Chest Diseases, RICU.

RESULTS

Mean age was 65.1 years. The mean APACHE II score was 23.7. Eighty-seven patients (57.6%) received mechanical ventilation (MV) via an endotracheal tube for more than 24 h. Twenty-two patients received non-invasive ventilation (NIV). Fifty patients died (33.1%) in hospital during the study period. The mortality rate was 52.9% in patients in need of MV. In the multivariate analysis, the need for intubation, inadequate metabolic compensation for respiratory acidosis, and low (=bad) Glasgow Coma Score (GCS) were determined as independent factors associated with mortality. The low GCS (OR: 0.61; CI: 0.48-0.78) and high APACHE II score (OR: 1.24; CI: 1.11-1.38) were determined as factors associated with intubation.

CONCLUSION

The most important predictors related to hospital mortality were the need for invasive ventilation and complications to MV. Adequate metabolic compensation for respiratory acidosis at admittance is associated with better survival. A high APACHE II score and loss of consciousness (low GCS) were independent predictors of a need to intubate patients.

Predictors of mortality in mechanically ventilated patients

OBJECTIVES

There are scarce data from India validating scoring systems used to predict outcome in patients requiring mechanical ventilation. This study prospectively compared the organ system failure (OSF), the acute physiology and chronic health evaluation (APACHE) II, and the APACHE III, scores on patients requiring mechanical ventilation in the medical intensive care unit, to predict outcome.

METHODS

200 consecutive patients requiring mechanical ventilation in a medical intensive care unit were recruited. OSF, APACHE II, and APCHE III scores were calculated at admission and daily for one week or until discharge in all patients. Other variables recorded include age, sex, diagnosis, oxygen therapy before ventilation, complications on ventilation, duration in hospital before ventilation, duration of ventilation, type of respiratory failure, alveolar arterial oxygen gradient, P/F ratio, use of tracheostomy, time on ventilator before tracheostomy, muscle relaxant used, fluid balance, inotrope support. Logistic regression analysis and area under the curve were computed to determine which variables independently predict outcome.

RESULTS

Of the 200 patients, at discharge 143 patients (71.5%) had died. The factors that independently predicted outcome among these patients on mechanical ventilation were the type of respiratory failure (type I) OR = 2.7 (p = 0.02), the use of inotropes OR 2.4 (p = 0.04), and the APACHE II score OR = 1.8 (p = 0.008) for every five point increase in APACHE II score.

CONCLUSIONS

Type 1 respiratory failure, the use of inotropes, and the APACHE II score measured at admission are significant independent predictors of mortality in the patients on mechanical ventilation.

Markers of exacerbation severity in chronic obstructive pulmonary disease

Background

Patients with chronic obstructive pulmonary disease (COPD) can experience 'exacerbations' of their conditions. An exacerbation is an event defined in terms of subjective descriptors or symptoms, namely dyspnoea, cough and sputum that worsen sufficiently to warrant a change in medical management. There is a need for reliable markers that reflect the pathological mechanisms that underlie exacerbation severity and that can be used as a surrogate to assess treatment effects in clinical studies. Little is known as to how existing study variables and suggested markers change in both the stable and exacerbation phases of COPD. In an attempt to find the best surrogates for exacerbations, we have reviewed the literature to identify which of these markers change in a consistent manner with the severity of the exacerbation event.

Methods

We have searched standard databases between 1966 to July 2004 using major keywords and terms. Studies that provided demographics, spirometry, potential markers, and clear eligibility criteria were included in this study. Central tendencies and dispersions for all the variables and markers reported and collected by us were first tabulated according to sample size and ATS/ERS 2004 Exacerbation Severity Levels I to III criteria. Due to the possible similarity of patients in Levels II and III, the data was also redefined into categories of exacerbations, namely out-patient (Level I) and in-patient (Levels II & III combined). For both approaches, we performed a fixed effect meta-analysis on each of the reported variables.

Results

We included a total of 268 studies reported between 1979 to July 2004. These studies investigated 142,407 patients with COPD. Arterial carbon dioxide tension and breathing rate were statistically different between all levels of exacerbation severity and between in out- and in-patient settings. Most other measures showed weak relationships with either level or setting, or they had insufficient data to permit meta-analysis.

Conclusion

Arterial carbon dioxide and breathing rate varied in a consistent manner with exacerbation severity and patient setting. Many other measures showed weak correlations that should be further explored in future longitudinal studies or assessed using suggested mathematical modelling techniques.

Predictors of mortality of patients with acute respiratory failure secondary to chronic obstructive pulmonary disease admitted to an intensive care unit: a one year study

Background

Patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) commonly require hospitalization and admission to intensive care unit (ICU). It is useful to identify patients at the time of admission who are likely to have poor outcome. This study was carried out to define the predictors of mortality in patients with acute exacerbation of COPD and to device a scoring system using the baseline physiological variables for prognosticating these patients.

Methods

Eighty-two patients with acute respiratory failure secondary to COPD admitted to medical ICU over a one-year period were included. Clinical and demographic profile at the time of admission to ICU including APACHE II score and Glasgow coma scale were recorded at the time of admission to ICU. In addition, acid base disorders, renal functions, liver functions and serum albumin, were recorded at the time of presentation. Primary outcome measure was hospital mortality.

Results

Invasive ventilation was required in 69 patients (84.1%). Fifty-two patients survived to hospital discharge (63.4%). APACHE II score at the time of admission to ICU {odds ratio (95 % CI): 1.32 (1.138–1.532); p < 0.001} and serum albumin (done within 24 hours of admission) {odds ratio (95 % CI): 0.114 (0.03-0.432); p = 0.001}. An equation, constructed using the adjusted odds ratio for the two parameters, had an area under the ROC curve of 91.3%. For the choice of cut-off, sensitivity, specificity, positive and negative predictive value for predicting outcome was 90%, 86.5%, 79.4% and 93.7%.

Conclusion

APACHE II score at admission and SA levels with in 24 hrs after admission are independent predictors of mortality for patients with COPD admitted to ICU. The equation derived from these two parameters is useful for predicting outcome of these patients.

Acute exacerbation of COPD requiring admission to the intensive care unit

OBJECTIVE

The aim of this study was to summarize experiences of patients admitted to the intensive care unit (ICU) for an acute exacerbation of COPD and to identify factors associated with a poor outcome.

METHODOLOGY

An observational case series of 102 consecutive admissions to the ICU for acute exacerbation of COPD between January 1998 and December 2002 were studied.

RESULTS

In total, 102 admissions to the ICU were reviewed. There were no ICU deaths but there were 18 hospital deaths (18%). A total of 28 patients were treated with non-invasive positive pressure ventilation (NIPPV), of whom four (14% failure rate) subsequently required intubation and mechanical ventilation (MV). Another 16 patients (16%) were successfully weaned from MV with NIPPV. Nine patients (9%), who had more than one episode of re-intubation after weaning (RAW), were from the mechanically ventilated group. Tracheostomy was performed for four patients (3.9%). The median duration of both NIPPV and MV was 1 day. The median length of stay in the ICU and hospital were 2 days (SD, 7.2) and 8 days (SD, 9.6), respectively. Univariate analysis identified serum total protein to be associated with hospital mortality (P = 0.004)

CONCLUSION

For patients with acute exacerbations of COPD in the ICU, serum total protein, a surrogate marker for nutrition, was significantly associated with hospital mortality.

In-hospital and 2-year survival of patients treated with mechanical ventilation for acute exacerbation of COPD

OBJECTIVE

To analyze in-hospital and 2-year survival of patients who require mechanical ventilation with intubation after acute respiratory failure due to exacerbation of chronic obstructive pulmonary disease (COPD). The secondary objective was to identify the prognostic factors for in-hospital mortality and mortality at 2 years.

PATIENTS AND METHODS

We retrospectively studied 101 patients with suspected COPD admitted to the intensive care unit between July 1993 and December 1998. Variables potentially related to mortality were analyzed with a univariate model and by logistic regression.

RESULTS

In-hospital survival was 74.3% and 2-year survival was 55.4%. Survival at 2 years was 81% for patients discharged from hospital. The variables associated with in-hospital mortality were age greater than 65 years, electrocardiographic diagnosis of chronic cor pulmonale, and development of multiorgan dysfunction syndrome. No factors predictive of mortality at 2 years were identified.

CONCLUSIONS

The in-hospital survival rate for patients with an acute exacerbation of COPD who require mechanical ventilation is good and the 2-year survival rate is acceptable. Age, electrocardiographic signs of cor pulmonale, and development of multiorgan dysfunction syndrome were associated with greater risk of in-hospital mortality.

Survival of patients with bronchiectasis after the first ICU stay for respiratory failure

STUDY OBJECTIVES

Respiratory failure (RF) is a frequent cause of death among patients with bilateral bronchiectasis. An ICU admission is commonly required, and neither short-term or long-term outcomes have been studied.

DESIGN

We performed a retrospective study over a 10-year period (January 1990 to March 2000). All patients with bilateral bronchiectasis admitted for the first time in the medical ICU for RF were reviewed. Patients with cystic fibrosis were excluded.

MEASUREMENTS AND RESULTS

Forty-eight patients (mean age +/- SD, 63 +/- 11 years; mean simplified acute physiology score [SAPS] II, 32 +/- 12) of whom 25% received long-term oxygen therapy (LTOT) were identified. All the patients were treated with intensive medical care, associated with noninvasive ventilation in 13 patients (27%), and 26 patients (54%) required intubation. Nine patients (19%) died in the ICU. The 1-year mortality rate was 40%. Among the variables recorded at ICU admission, age > 65 years (p = 0.002), SAPS II score > 32 (p = 0.012), use of LTOT (p = 0.047), and intubation (p = 0.027) were associated with reduced survival in univariate analysis by Cox regression. Multivariate analysis by Cox proportional hazard model showed that age > 65 years (relative risk [RR], 2.70; 95% confidence interval [CI], 1.15 to 6.29) and use of LTOT (RR, 2.52; 95% CI, 1.15 to 5.54) were independently associated with reduced survival.

CONCLUSIONS

We performed the first study providing information related to the impact of the first ICU stay for RF on long-term outcomes for patients with bilateral bronchiectasis. Age > 65 years and prior use of LTOT were associated with reduced survival.

Outcome of coal worker's pneumoconiosis with acute respiratory failure

STUDY OBJECTIVE

To investigate the clinical features and prognosis of patients with coal worker's pneumoconiosis (CWP) requiring invasive mechanical ventilation (MV) in the ICU for their first episode of acute respiratory failure (ARF), with special attention to the prognostic implication of radiographic progressive massive fibrosis (PMF).

DESIGN

Retrospective study.

SETTING

A 16-bed medical ICU at a community hospital.

PATIENTS AND METHODS

We reviewed 53 patients with CWP and ARF requiring invasive MV in the ICU for the first time between August 1998 and March 2002.

RESULTS

Of the 53 patients with CWP, 28 patients (53%) with PMF had their first ARF at a younger age than those without PMF (69.1 +/- 7.9 years vs 74.8 +/- 7.2 years, p = 0.008 [mean +/- SD]). Pneumonia (49%) was the most common cause of ARF. The mean APACHE (acute physiology and chronic health evaluation) II score was 26.0 +/- 9.9, and the mean ICU stay was 14.7 +/- 16.1 days. Twenty-one patients (40%) were weaned successfully in the ICU, with mean ventilator time of 17.0 +/- 25.1 days. The ICU and in-hospital mortality rates were 40% and 43%, respectively. The median survivals for all patients and the ICU survivors were 2.6 months and 14.3 months, respectively. Multivariate analysis showed the following risk (or protective) factors for the ICU mortality: PaCO(2) > 45 mm Hg at the time of intubation (adjusted odds ratio [OR], 0.04; 95% confidence interval [CI], 0.003 to 0.44), PaO(2)/fraction of inspired oxygen ratio < 200 mm Hg at the time of intubation (OR, 8.78; 95% CI, 1.36 to 56.48), and APACHE II score >or= 25 (OR, 11.99; 95% CI, 1.49 to 96.78). PMF was not associated with the ICU mortality (OR, 1.18; 95% CI, 0.20 to 7.10).

CONCLUSIONS

Radiographic PMF was not associated with the ICU mortality in patients with CWP and ARF receiving invasive MV in the ICU. Although a substantial proportion of them could be weaned from the ventilator and discharged from the hospital, their long-term prognosis was poor.

Descompensaciones respiratorias en la enfermedad pulmonar obstructiva crónica

La descompensación en la enfermedad pulmonar obstructiva crónica (EPOC) se define como el agravamiento, en general rápido y reversible, de la situación respiratoria en un paciente con EPOC. Estos trastornos son secundarios a trastornos sobreañadidos que requieren un tratamiento específico (neumopatías infecciosas, embolias pulmonares, neumotórax, insuficiencia cardíaca izquierda, errores terapéuticos, etc.) o a exacerbaciones de los fenómenos inflamatorios bronquiales y de los síntomas crónicos (broncorrea, tos, disnea). Su gravedad es variable y oscila entre las formas bien toleradas que pueden tratarse de manera ambulatoria con un coste escaso y las dificultades respiratorias agudas que precisan reanimación inmediata. La utilización razonada de antibióticos, broncodilatadores en dosis altas, corticoides, oxígeno y ventilación asistida (casi siempre «no invasiva») ha mejorado su pronóstico, que sigue siendo mediocre cuando la descompensación se superpone a una EPOC evolucionada.

Prognostic factors, clinical course, and hospital outcome of patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure

OBJECTIVE

To describe prognostic factors, clinical course, and hospital outcome of patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure.

DESIGN

Analysis of prospectively collected data.

SETTING

A multidisciplinary intensive care unit of an inner-city university hospital.

PATIENTS

Patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure from August 1995 through July 1998.

MEASUREMENTS AND MAIN RESULTS

Data were obtained concerning demographics, arterial blood gas, Acute Physiology and Chronic Health Evaluation (APACHE) II score, sepsis, mechanical ventilation, organ failure, complications, and hospital mortality rate. Fifty-nine percent of patients were male, 63% white, and 36% African-American; the mean age was 63.1 +/- 8.9 yrs. Noninvasive mechanical ventilation was tried in 40% of patients and was successful in 54% of them. Invasive mechanical ventilation was required in 61% of the 250 admissions. Sepsis developed in 31% of patients, nonpulmonary organ failure in 20%, pneumothorax in 3%, and acute respiratory distress syndrome in 2%. Multiple organ failure developed in 31% of patients with sepsis compared with 3% without sepsis (p <.0001). Predicted and observed hospital mortality rates were 30% and 15%, respectively. Differences in age and arterial carbon dioxide and oxygen tensions between survivors and nonsurvivors were not significant. Arterial pH was lower in nonsurvivors than in survivors (7.21 vs. 7.25, p =.0408). The APACHE II-predicted mortality rate (p =.0001; odds ratio, 1.046; 95% confidence interval, 1.022-1.070) and number of organ failures (p <.0001; odds ratio, 5.524; 95% confidence interval, 3.041-10.031) were independent predictors of hospital outcome; invasive mechanical ventilation was not an independent predictor.

CONCLUSIONS

Physiologic abnormalities at admission to an intensive care unit and development of nonrespiratory organ failure are important predictors of hospital outcome for critically ill patients with chronic obstructive pulmonary disease who have acute respiratory failure. Improved outcome would require prevention and appropriate treatment of sepsis and multiple organ failure.

Predictors of outcome for patients with COPD requiring invasive mechanical ventilation

INTRODUCTION

Accurate outcomes data and predictors of outcomes are fundamental to the effective care of patients with COPD and in guiding them and their families through end-of-life decisions.

DESIGN

We conducted a retrospective cohort study of 166 patients using prospectively gathered data in patients with COPD who required mechanical ventilation for acute respiratory failure of diverse etiologies.

RESULTS

The in-hospital mortality rate for the entire cohort was 28% but fell to 12% for patients with a COPD exacerbation and without a comorbid illness. Univariate analysis showed a higher mortality rate among those patients who required > 72 h of mechanical ventilation (37% vs 16%; p < 0.01), those without previous episodes of mechanical ventilation (33% vs 11%; p < 0.01), and those with a failed extubation attempt (36% vs 7%; p = 0.0001). With multiple logistical regression, higher acute physiology score measured 6 h after the onset of mechanical ventilation, presence of malignancy, presence of APACHE (acute physiology and chronic health evaluation) II-associated comorbidity, and the need for mechanical ventilation > or = 72 h were independent predictors of poor outcome.

CONCLUSIONS

We conclude that among variables available within the first 6 h of mechanical ventilation, the presence of comorbidity and a measure of the severity of the acute illness are predictors of in-hospital mortality among patients with COPD and acute respiratory failure. The occurrence of extubation failure or the need for mechanical ventilation beyond 72 h also portends a worse prognosis.

Respiratory intensive care units in Italy: a national census and prospective cohort study

BACKGROUND

In Italy, respiratory intensive care units (RICUs) provide an intermediate level of care between the intensive care unit (ICU) and the general ward for patients with single organ respiratory failure. Because of the lack of official epidemiological data in these units, a two phase study was performed with the aim of describing the work profile in Italian RICUs.

METHODS

A national survey of RICUs was conducted from January to March 1997 using a questionnaire which comprised over 30 items regarding location, models of service provision, staff, and equipment. The following criteria were necessary for inclusion of a unit in the survey: (1) a nurse to patient ratio ranging from 1:2.5 to 1:4 per shift; (2) availability of adequate continuous non-invasive monitoring; (3) expertise for non-invasive ventilation (NIV) and for intubation in case of NIV failure; (4) physician availability 24 hours a day. Between November 1997 and January 1998 a 3 month prospective cohort study was performed to survey the patient population admitted to the RICUs.

RESULTS

Twenty six RICUs were included in the study: four were located in rehabilitation centres and 22 in general hospitals. In most, the reported nurse to patient ratio ranged from 1:2 to 1:3, with 36% of units reporting a ratio of 1:4 per shift. During the study period 756 consecutive patients of mean (SD) age 68 (12) years were admitted to the 26 RICUs. The highest proportion (47%) were admitted from emergency departments, 19% from other medical wards, 18% were transferred from the ICU, 13% from specialist respiratory wards, and 2% were transferred following surgery. All but 32 had respiratory failure on admission. The reasons for admission to the RICU were: monitoring for expected clinical instability (n=221), mechanical ventilation (n=473), and weaning (n=59); 586 patients needed mechanical ventilation during their stay in the RICU, 425 were treated with non-invasive techniques as a first line of treatment (374 by non-invasive positive pressure, 51 by iron lung), and 161 underwent invasive mechanical ventilation (63 intubated, 98 tracheostomies). All but 48 patients had chronic respiratory disease, mainly chronic obstructive pulmonary disease (COPD; n=451). More than 70% of patients (n=228) had comorbidity, mainly consisting of heart disorders. The median APACHE II score was 18 (range 1--43). The predicted inpatient mortality risk rate according to the APACHE II equation was 22.1% while the actual inpatient mortality rate was 16%. The mean length of stay in the RICU was 12 (11) days. The outcome in most patients (79.2%) admitted to RICUs was favourable.

CONCLUSIONS

Italian RICUs are specialised units mainly devoted to the monitoring and treatment of acute on chronic respiratory failure by non-invasive ventilation, but also to weaning from invasive mechanical ventilation. The results of this study provide a useful insight into an increasingly important field of respiratory medicine.

Management of acute exacerbations of COPD: a summary and appraisal of published evidence

STUDY OBJECTIVES

To critically review the available data on the diagnostic evaluation, risk stratification, and therapeutic management of patients with acute exacerbations of COPD.

DESIGN, SETTING, AND PARTICIPANTS

English-language articles were identified from the following databases: MEDLINE (from 1966 to week 5, 2000), EMBASE (from 1974 to week 18, 2000), HealthStar (from 1975 to June 2000), and the Cochrane Controlled Trials Register (2000, issue 1). The best available evidence on each subtopic then was selected for analysis. Randomized trials, sometimes buttressed by cohort studies, were used to evaluate therapeutic interventions. Cohort studies were used to evaluate diagnostic tests and risk stratification. Study design and results were summarized in evidence tables. Individual studies were rated as to their internal validity, external validity, and quality of study design. Statistical analyses of combined data were not performed.

MEASUREMENT AND RESULTS

Limited data exist regarding the utility of most diagnostic tests. However, chest radiography and arterial blood gas sampling appear to be useful, while short-term spirometry measurements do not. In terms of the risk of relapse and the risk of death after hospitalization for an acute exacerbation, there are identifiable clinical variables that are associated with these outcomes. Therapies for which there is evidence of efficacy include bronchodilators, corticosteroids, and noninvasive positive-pressure ventilation. There is also support for the use of antibiotics in patients with more severe exacerbations. Based on limited data, mucolytics and chest physiotherapy do not appear to be of benefit, and oxygen supplementation appears to increase the risk of respiratory failure in an identifiable subgroup of patients.

CONCLUSIONS

Although suggestions for appropriate management can be made based on available evidence, the supporting literature is spotty. Further high-quality research is needed and will require an improved, generally acceptable, and transportable definition of the syndrome "acute exacerbation of COPD" and improved methods for observing and measuring outcomes.

Noninvasive positive pressure ventilation in the setting of severe, acute exacerbations of chronic obstructive pulmonary disease: more effective and less expensive

OBJECTIVE

The use of noninvasive ventilation for patients with acute respiratory failure has become increasingly popular over the last decade. Although the literature provides good evidence for the effectiveness of noninvasive ventilation in addition to standard therapy compared with standard therapy alone in patients with chronic obstructive pulmonary disease (avoiding intubation and improving hospital mortality), the associated costs have not been rigorously measured. Adding noninvasive positive pressure ventilation (NPPV) to standard therapy in the setting of a severe, acute exacerbation of chronic obstructive pulmonary disease (COPD) in patients with respiratory acidosis who are at high risk of requiring endotracheal intubation is both more effective and less expensive.

DESIGN

Economic evaluation based on theoretical model.

SETTING

This analysis base case was modeled for a tertiary care, teaching hospital.

PATIENTS OR OTHER PARTICIPANTS

Carefully selected patients with severe exacerbations of COPD.

INTERVENTION

The two alternative therapies compared were standard therapy (oxygen, bronchodilators, steroids, and antibiotics) and standard therapy plus NPPV.

MEASUREMENTS AND MAIN RESULTS

As the hypothesis was dominance, the main outcomes modeled and calculated were costs, mortality rate, and rates of intubation between the two interventions. To determine clinical effectiveness, we used a meta-analysis of randomized trials evaluating the impact of NPPV on hospital survival. A decision tree was constructed and probabilities were applied at each chance node using research evidence and a comprehensive regional database. To provide data for this economic evaluation, MEDLINE literature searches were conducted. Bibliographies of relevant articles were reviewed, as were personal files. To estimate the costs of the alternative therapeutic approaches, eight types of hospitalization days were costed using the London Health Sciences Center costing data. Sensitivity analyses were performed, varying all assumptions made. The meta-analysis yielded an odds ratio for hospital mortality in the NPPV arm, compared with standard therapy, of 0.22 (95% confidence interval, 0.10-0.66). By using baseline case assumptions, we found a cost savings of $3,244 (1996, Canadian), per patient admission, if NPPV were adopted in favor of standard therapy. These findings present a scenario of clear dominance for treatment with NPPV. Sensitivity analyses did not alter the results appreciably.

CONCLUSIONS

We conclude that from a hospital's perspective, NPPV and standard therapy for carefully selected patients with acute, severe exacerbations of COPD are more effective and less expensive than standard therapy alone.

The impact of long-term acute-care facilities on the outcome and cost of care for patients undergoing prolonged mechanical ventilation

OBJECTIVES

To compare the 6-month mortality rate of chronically ventilated patients treated either exclusively in a traditional acute-care hospital or transferred during hospitalization to a long-term acute-care facility. To analyze the hospital cost of care and estimate the amount of uncompensated care incurred by acute-care hospitals under the Medicare prospective payment diagnostic related groups system.

DESIGN

Retrospective chart review and questionnaire.

SETTING

Fifty-four acute-care referral hospitals and 26 longterm acute-care institutions.

PATIENTS

A total of 432 ventilated patients selected from 3,266 patients referred but not transferred to a study long-term acute-care facility and 1,702 ventilated patients from 4,174 patients referred and then subsequently transferred to the long-term acute-care facility. Six-month outcomes were determined for the subgroup of patients > or =65 yrs old (279 and 1,340 patients, respectively). Hospital charges were available for 192 of the 279 nontransferred patients who were > or =65 yrs old and 1,332 of the 1,340 transferred patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 6-month mortality rate was 67.4% for the 279 nontransferred patients and 67.2% for the 1,340 transferred patients. On multiple regression analysis, variables associated with the 6-month mortality rate included initial admitting diagnosis, age, the acute physiology score, and presence of decubitus ulcer. After controlling for these variables, there was no significant difference in 6-month mortality rate, but admission to the long-term acute-care facility was associated with a longer mean survival time. Average total hospital costs for the 192 nontransferred patients was $78,474, and estimated Medicare reimbursement was $62,472, resulting in an average of $16,002 of uncompensated care per patient. Estimated costs for the long-term acute-care facility admissions were $56,825.

CONCLUSIONS

Patients undergoing prolonged ventilation have high hospital and 6-month mortality rates, and 6-month outcomes are not significantly different for those transferred to long-term acute-care facilities. These patients generate high costs, and acute-care hospitals are significantly underreimbursed by Medicare for these costs. Acute-care hospitals can reduce the amount of uncompensated care by earlier transfer of appropriate patients to a long-term acute-care facility.

Ventilation in a Birmingham intensive care unit 1993-1995: outcome for patients with chronic obstructive pulmonary disease

The aims of the study were to look at information on which the decision to ventilate chronic obstructive pulmonary disease (COPD) patients admitted to an intensive care unit (ITU) was based (including whether there was discussion with the patient, relatives and consultant), to identify indicators of poor prognosis, and to assess the outcomes of ventilation and functional capacity after discharge. A retrospective study of 27 months of admissions was carried out. The following variables were studied to see if they influenced prognosis: premorbid history, admission diagnosis, consultant involvement in the decision to transfer to ITU, admission chest radiograph, sputum bacteriology, arterial blood gases, APACHE II scores, duration of ventilation and complications in ITU. In-hospital mortality, post-discharge mortality and length of hospital stay were recorded. Functional capacity after discharge was assessed from the hospital clinic records and from general practitioners. Forty-six percent of case notes had inadequate premorbid information and no documented discussion occurred in 66% of patients/relatives. Poor prognostic indicators were admissions after cardiorespiratory arrest, cases discussed with consultants regarding ITU transfer, previous therapy with long-term oral steroids, and developing renal or cardiac failure in ITU. APACHE II scores were higher in the group that died. There was 49% hospital mortality and 59% 1-year mortality. Fifty-three percent of survivors were dependent upon carers and housebound, and general practitioners felt that 59% of survivors had a higher dependence on carers, a worse exercise tolerance and a poorer quality of life than before admission. The decision to ventilate is often made with inadequate background history, which could be sought from general practitioners, hospital case notes and family. There is significant morbidity and mortality following ventilation. Further prospective studies are required to help select which COPD patients should be ventilated.

Acute exacerbations of chronic obstructive pulmonary disease and mechanical ventilation: a reevaluation

OBJECTIVE

To review the intensive care unit (ICU) experience of patients admitted with acute exacerbations of chronic obstructive pulmonary disease.

DESIGN

Retrospective case series.

SETTING

University teaching hospital.

PATIENTS

We reviewed the records of 100 consecutive ICU admissions of patients with acute exacerbations of chronic obstructive pulmonary disease over a period of 4.25 yrs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were characterized using a computerized prospective database and case note review. Multivariate analysis identified variables predicting ICU and hospital length of stay. The Cox proportional hazards model was used to analyze survival after hospital discharge. Seventy-five patients (24 female and 51 male, mean age 68.5 +/- 7 [SD] yrs) with 100 ICU admissions were identified. Premorbid airway obstruction was severe, with forced expiratory volume in 1 sec (FEV1)/forced vital capacity (FVC) of 0.7 +/- 0.34 L and FEV1/FVC of 39 +/- 16%. Thirty-two percent received home-administered oxygen and 42% were housebound. The pre-ICU admission PaCO2 was 86 +/- 28 torr (11.5 +/- 3.7 kPa), with a pH of 7.24 +/- 0.11 and a PaO2/FIO2 of 190 +/- 66. ICU admission Acute Physiology and Chronic Health Evaluation II score was 18 +/- 5. Forty-three patients were mechanically ventilated for a median of 4 days (range 0.08 to 30). Tracheostomy, in seven patients, was maintained for 21 +/- 7 days. Ventilation time and tracheostomy frequency predicted length of ICU stay (median 3 days; range 1 to 40) and hospital stay (17 days; 4 to 97), respectively. ICU and hospital case-fatality rates were 1% and 11%. Out-of-hospital (24-month) probability of survival was predicted by plasma albumin concentration at the time of ICU admission; this probability of survival was .64 at an albumin concentration of 38 g/L.

CONCLUSIONS

ICU admission of severely ill chronic obstructive pulmonary disease patients results in acceptable outcomes. Survival of < or =2 yrs is not affected by mechanical ventilation or tracheostomy requirement.

Predicting the duration of mechanical ventilation. The importance of disease and patient characteristics

STUDY OBJECTIVE

To analyze the determinants of an individual patient's duration of mechanical ventilation and assess interhospital variations for average durations of ventilation.

DESIGN

Prospective, multicenter, inception, cohort study.

SETTING

Forty-two ICUs at 40 US hospitals.

PATIENTS

A total of 5,915 patients undergoing mechanical ventilation on ICU day 1 selected from the acute physiology and chronic health evaluation (APACHE) III database of 17,440 admissions.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Utilizing APACHE III data collected on the 5,915 patients, multivariate regression analysis was performed on selected patients and disease characteristics to determine which variables were significantly associated with the duration of mechanical ventilation. An equation predicting duration of ventilation was then developed using the significant predictor variables and its accuracy was evaluated. Variables significantly associated with duration of ventilation included primary reason for ICU admission, day 1 acute physiology score (APS) of APACHE III, age, prior patient location and hospital length of stay, activity limits due to respiratory disease, serum albumin, respiratory rate, and PaO2/FIo2 measurements. Using an equation derived from these variables, predicted durations of ventilation were then calculated and compared with actual observed durations for each of the 42 ICUs. Average duration of ventilation for the 42 ICUs ranged from 2.6 to 7.9 days, but 60% of this variation was accounted for by differences in patient characteristics.

CONCLUSIONS

For patients admitted to the ICU and ventilated on day 1, total duration of ventilation is primarily determined by admitting diagnosis and degree of physiologic derangement as measured by APS. An equation developed using multivariate regression techniques can accurately predict average duration of ventilation for groups of ICU patients, and we believe this equation will be useful for comparing ventilator practices between ICUs, controlling for patient differences in clinical trials of new therapies or weaning techniques, and as a quality improvement mechanism.

Predicting mortality of patients hospitalized for acutely exacerbated chronic obstructive pulmonary disease

PURPOSE

To identify factors affecting the short-term prognosis of patients with acutely exacerbated chronic obstructive pulmonary disease (COPD).

PATIENTS AND METHODS

The 590 patients having COPD as primary disease who were hospitalized in the pneumology unit of a university hospital from 1981 to 1990 were studied. A standardized protocol for the treatment of acutely exacerbated COPD was adopted for all the patients. The patient records were retrospectively analyzed by two observers, and 23 clinical and laboratory variables defining the patient status on admission were collected. Age and arterial gas data were also taken into account, and the outcome mortality was recorded. Interobserver reproducibility was tested by computing the kappa coefficient and Spearman's rho for dichotomous and continuous variables, respectively. The relationship of clinical and laboratory factors to the outcome was assessed first by univariate analysis and then by a logistic regression analysis assessing the independent predictive role of variables previously shown to be univariately correlated with mortality.

RESULTS

The mortality rate was 14.4%. The logistic regression analysis identified four independent predictors of death: age (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.04 to 1.11), alveolar-arterial oxygen gradient greater than 41 mm Hg (OR 2.33; 95% CI 1.39 to 3.90), ventricular arrhythmias (OR 1.91; 95% CI 1.10 to 3.31), and atrial fibrillation (OR 2.27; 95% CI 1.14 to 4.51).

CONCLUSIONS

Patients with acutely exacerbated COPD having a high risk of death can be identified at the time of admission. Variables reflecting heart dysfunction are important determinants of this risk. Among pulmonary function data, only alveolar-arterial oxygen gradient contributes to the predictive model.

Ethics committees: group process concerns and the need for research

Few ethics committees were in place when the New Jersey Supreme Court announced its ruling on the Quinlan case in 1976. Today, the vast majority of hospitals have formed ethics committees and their use in nursing homes and other healthcare facilities is growing. Given the increasing commitment to the use of ethics committees and their increasing influence on healthcare decision making, the careful evaluation of committee performance should be a high priority. Yet to date ethics committees appear to have undergone relatively little scrutiny. While professional articles on ethics committees do appear and at least one journal (CQ) sets aside a regular section for the discussion of “Ethics Committees at Work” articles to date have primarily been limited to essays, philosophical inquiries, reports, case studies, and, occasionally, surveys. The use of more structured research methodologies has been lacking. As a result, it is not yet clear, for example, what characteristics describe the best functioning ethics committee. Indeed, what constitutes best functioning lacks careful definition as well. Committee impact on medical decision making and patient outcomes, while discussed, has not been systematically measured and analyzed.

Survival and long-term follow-up of tracheostomized patients with COPD treated by home mechanical ventilation. A multicenter French study in 259 patients. French Cooperative Study Group

To define more clearly the value of home mechanical ventilation by tracheostomy (HMVT) in patients with advanced COPD, a retrospective French multicenter study group analyzed the prognostic factors and long-term survival of 259 patients with severe COPD, who were tracheostomized for at least 1 year. Seventy-eight percent of the patients died by the end of the observation period. The actuarial survival rate for the overall study population was, therefore, 70 percent at 2 years, 44 percent at 5 years, and 20 percent at 10 years. These results appear to be better than those of the major published series and compare to the prognosis of COPD patients treated by long-term oxygen therapy (LTO) 15 hr/24 hr. The parameters most closely correlated with a survival for more than 5 years were age < 65 years, use of an uncuffed cannula, and a PaO2 > 55 mm Hg in room air during the 3 months after tracheostomy (p < 0.01). This study, therefore, confirmed the feasibility of HMVT in COPD and should lead to a review of the place of permanent tracheostomy in the long-term prognosis of severe COPD patients.

Severe COPD and acute respiratory failure. Correlates for survival at the time of tracheal intubation

The recognition of a reversible cause for acute respiratory failure (ARF) is frequently difficult in patients with severe chronic obstructive pulmonary disease (COPD). We sought to identify clinical findings present at the time of tracheal intubation that were associated with successful weaning and short-term survival among a population of male veterans with severe COPD. Over a 5-year period (1987 to 1991), 39 episodes of ARF requiring mechanical ventilation (MV) were identified in 33 men with severe COPD. All the patients had a baseline FEV1 < 1 L. Univariate analysis suggested a higher serum albumin level and absence of pulmonary infiltrates on chest radiography distinguished survivors (weaned from MV for 72 h) from nonsurvivors (died while undergoing MV or within 72 h of weaning). Multivariate analysis revealed the absence of pulmonary infiltrates on initial chest radiography was the strongest correlate for survival. To examine the significance of these correlates in ARF complicating milder COPD, 19 patients with lesser degrees of chronic airways obstruction and ARF were also studied. Unlike patients with severe COPD, the presence or absence of pulmonary infiltrates on chest radiography was not correlated with survival in patients with milder chronic airways obstruction. Analyzing all COPD patients with ARF, the mortality risk associated with the presence of pulmonary infiltrates on chest radiography increased dramatically with declining baseline lung function. Mortality risk ratio analysis revealed the greatest likelihood for survival was predicted by a higher baseline FEV1 and the absence of pulmonary infiltrates on chest radiography. The extent of baseline airways obstruction alone was not correlated with short-term survival in either group. These observations suggest that in the subset of patients with severe COPD and ARF, the presence of pulmonary infiltrates on chest radiography at the time of tracheal intubation may be associated with less likelihood for survival. An exacerbation of COPD may infrequently be the terminal illness in these patients.