Ilio-psoas hematoma in the intensive care unit: a multicentric study

Background

Clinical features and outcomes of patients with spontaneous ilio-psoas hematoma (IPH) in intensive care units (ICUs) are poorly documented. The objectives of this study were to determine epidemiological, clinical, biological and management characteristics of ICU patients with IPH.

Methods

We conducted a retrospective multicentric study in three French ICUs from January 2006 to December 2014. We included IPH diagnosed both at admission and during ICU stay. Surgery and embolization were available 24 h a day for each center, and therapeutic decisions were undertaken after pluridisciplinary discussion. All IPHs were diagnosed using CT scan.

Results

During this period, we identified 3.01 cases/1000 admissions. The mortality rate of the 77 included patients was 30 %. In multivariate analysis, we observed that mortality was independently associated with SAPS II (OR 1.1, 95 % CI [1.013–1.195], p = 0.02) and with the presence of hemorrhagic shock (OR 67.1, 95 % CI [2.6–1691], p = 0.01). We found IPH was related to anticoagulation therapy in 56 cases (72 %), with guideline-concordant reversal performed in 33 % of patients. We did not found any association between anticoagulant therapy type and outcome.

Conclusion

We found IPH is an infrequent disease, with a high mortality rate of 30 %, mostly related to anticoagulation therapy and usually affecting the elderly. Management of anticoagulation-related IPH includes a high rate of no reversal of 38 %.

Granulocytic myeloid-derived suppressor cells inversely correlate with plasma arginine and overall survival in critically ill patients

Critically ill patients display a state of immunosuppression that has been attributed in part to decreased plasma arginine concentrations. However, we and other authors have failed to demonstrate a clinical benefit of L-arginine supplementation. We hypothesize that, in these critically ill patients, these low plasma arginine levels may be secondary to the presence of granulocytic myeloid-derived suppressor cells (gMDSC), which express arginase known to convert arginine into nitric oxide (NO) and citrulline. Indeed, in a series of 28 non-surgical critically ill patients, we showed a dramatic increase in gMDSC compared to healthy subjects (P = 0·0002). A significant inverse correlation was observed between arginine levels and gMDSC (P = 0·01). As expected, gMDSC expressed arginase preferentially in these patients. Patients with high gMDSC levels on admission to the medical intensive care unit (MICU) presented an increased risk of death at day 7 after admission (P = 0·02). In contrast, neither plasma arginine levels, monocytic MDSC levels nor neutrophil levels were associated with overall survival at day 7. No relationship was found between body mass index (BMI) or simplified acute physiology score (SAPS) score, sequential organ failure assessment (SOFA) score or gMDSC levels, eliminating a possible bias concerning the direct prognostic role of these cells. As gMDSC exert their immunosuppressive activity via multiple mechanisms [production of prostaglandin E2 (PGE2 ), interleukin (IL)-10, arginase, etc.], it may be more relevant to target these cells, rather than simply supplementing with L-arginine to improve immunosuppression and its clinical consequences observed in critically ill patients.

Assessment of five screening strategies for optimal detection of carriers of third-generation cephalosporin-resistant Enterobacteriaceae in intensive care units using daily sampling

There is no consensus on optimal screening procedures for multidrug-resistant Enterobacteriaceae (MDRE) in intensive care units (ICUs). Therefore, we assessed five strategies for the detection of extended-spectrum beta-lactamase (ESBL) and high-level expressed AmpC cephalosporinase (HL-CASE) producers. During a 3-month period, a rectal screening swab sample was collected daily from every ICU patient, from the first 24 h to the last day of ICU stay. Samples were plated on MDRE-selective media. Bacteria were identified using MALDI-TOF mass spectrometry and antibiograms were performed using disk diffusion. MDREs were isolated from 682/2348 (29.0%) screening samples collected from 93/269 (34.6%) patients. Incidences of patients with ESBL and HL-CASE producers were 17.8 and 19.3 per 100 admissions, respectively. In 48/93 patients, MDRE carriage was intermittent. Compared with systematic screening at admission, systematic screening at discharge did not significantly increase the rate of MDRE detection among the 93 patients (62% vs. 70%). In contrast, screening at admission and discharge, screening at admission and weekly thereafter, and screening at admission and weekly thereafter and at discharge significantly increased MDRE detection (77%, p 0.02; 76%, p 0.01; 86%, p<0.001, respectively). The difference in MDRE detection between these strategies relies essentially on the levels of detection of patients with HL-CASE producers. The most reasonable strategy would be to collect two samples, one at admission and one at discharge, which would detect 87.5% of the ESBL strains, 67.3% of the HL-CASE strains and 77.4% of all MDRE strains. This study should facilitate decision-making concerning the most suitable screening policy for MDRE detection in a given ICU setting.

Drowning associated pneumonia: a descriptive cohort

PURPOSE

Pneumonia is the most common infectious complication of drowning. Pneumonia is potentially life threatening and should be treated by effective antibiotic therapy. However the risk factors, microbiological causes, diagnostic approach and appropriate therapy for pneumonia associated with drowning are not well described. The microbiological ecology of the body of water where immersion occurred could be of import. The aim of this study was to report on microorganisms involved in pneumonia associated with drowning and out of hospital cardiac arrest after successful cardiopulmonary resuscitation. Additionally, we retrieved and undertook microbiological analysis on samples of water from our local river.

METHODS

This retrospective study included all patients having suffered an out of hospital cardiac arrest due to drowning and admitted to our tertiary care academic hospital between 2002 and 2010. Data concerning bacteriological lung samples (tracheal aspirate or bronchoalveolar lavage) at admission were reported and compared to bacteriological samples obtained from our local river (the river Seine).

RESULTS

A total of thirty-seven patients were included in the study. Lung samples were obtained for twenty-one of these patients. Lung samples were positive in nineteen cases, with a high frequency of multi-drug resistant bacteria. Samples from the Seine River found microorganisms similar to those found in drowning associated pneumonia.

CONCLUSIONS

Drowning associated pneumonia can be due to multi drug resistant bacteria. When treating drowning associated pneumonia, antibiotics should be effective against bacteria similar to those found in the body of water where immersion occurred.

[Acute respiratory distress syndrome due to Toxocara cati infection]

Human toxocarosis is a helminthozoonosis due to the migration of toxocara species larvae throughout the human body. Lung manifestations vary and range from asymptomatic infection to severe disease. Dry cough and chest discomfort are the most common respiratory symptoms. Clinical manifestations include a transient form of Loeffler's syndrome or an eosinophilic pneumonia. We report a case of bilateral pneumonia in an 80 year old caucasian man who developed very rapidly an acute respiratory distress syndrome, with a PaO2/FiO2 ratio of 55, requiring mechanical ventilation and adrenergic support. There was an increased eosinophilia in both blood and bronchoalveolar lavage fluid. Positive toxocara serology and the clinical picture confirmed the diagnosis of the "visceral larva migrans" syndrome. Intravenous corticosteroid therapy produced a rapid rise in PaO2/FiO2 before the administration of specific treatment. A few cases of acute pneumonia requiring mechanical ventilation due to toxocara have been published but this is, to our knowledge, is the first reported case of ARDS with multi-organ failure.

Diagnosis and treatment of nosocomial pneumonia in ALI/ARDS patients

Ventilator-associated pneumonia (VAP) is a common complication of the acute respiratory distress syndrome (ARDS) or acute lung injury (ALI), often leading to the development of sepsis, multiple organ failure, and death. However, the diagnosis of pulmonary infection in patients with ARDS/ALI is often difficult: the systemic signs of infection, such as fever, tachycardia, leukocytosis are nonspecific findings in such patients; a variety of causes other than pneumonia can explain asymmetric consolidation in patients with ARDS and marked asymmetry of radiographic abnormalities has also been reported in patients with uncomplicated ARDS. In 2003, physicians in charge of these patients have to identify patients with true bacterial lung infection, to select appropriate initial antibiotic therapy, to adjust therapy as soon as possible, and to withhold antibiotics in patients without VAP. To do that, a bacteriological strategy based on the use of quantitative cultures of specimen obtained with fibreoptic bronchoscopy performed before initiation or modification of antibiotic treatment seems better than a strategy based on clinical evaluation alone, lowering antibiotic consumption and improving outcome. When bronchoscopy is not available or contraindicated, a nonbronchoscopic strategy or a clinical strategy with reevaluation 3 days after initiation of treatment may be used. Antimicrobial treatment of VAP is a complex issue. Some general principles can be helpful for the selection of initial treatment: knowledge of most frequently identified responsible pathogens and their susceptibility patterns in the unit; prior duration of hospitalisation; previously prescribed antibiotics; information obtained by direct examination of pulmonary secretions; antibacterial activity and pharmacodynamic characteristics of antibiotics that could be used to treat this infection. Appropriateness of initial antimicrobial therapy is probably a major prognostic factor for patients with ventilator-associated pneumonia. Thus, before new antiboitics are administered, reliable pulmonary specimens must be obtained for direct examination and cultures.

[Epidemiology and antibiotic therapy in nosocomial pneumonia]

Nosocomial pneumonia occurs in 0.5 to 1.5% of all hospitalized patients and in 10 to 30% of those under artificial ventilation. The main causal agents are Staphylococcus aureus and resistant Gram-negative bacilli, particularly Pseudomonas aeruginosa. In case of early onset (before the fifth day), Haemophilus influenzae, Streptococcus pneumoniae and susceptible enterobacteria predominate. These infections are associated with overmortality, particularly in patients with P. aeruginosa pneumonia, severe respiratory failure, shock syndrome or given a poorly adapted antibiotic regimen. Management of patients with nosocomial pneumonia depends on the clinical presentation and prior bacteriology data often leading to empiric antibiotic prescription. Published guidelines, for example those recommended by the American Thoracic Society, can also be used to adapt the antibiotic therapy as a function of the severity of the clinical situation, the patient's comorbidities, and the date of onset. This type of strategy remains to be evaluated. It would be advisable to base therapeutic management on reliable microbiological data allowing selection of patients requiring antibiotics and treatment based on culture results. Currently a two-drug regimen is recommended for nosocomial pneumonia due to P. aeruginosa or particularly resistant strains.

[Duration of treatment of nosocomial pneumonia. What judgement criteria to use?]

AN UNRESOLVED ISSUE: Inappropriate duration of antibiotic treatment is one of the factors explaining the high mortality of nosocomial pneumonia. There are however few data on the ideal duration of treatment. An improvement in the radiological image is not a good criterion. The right duration would be one that is necessary and sufficient to achieve cure and avoid recurrence and relapse and also one that avoids the drawbacks of prolonged treatment. LIMITATIONS OF CLINICAL CRITERIA: High-grade fever, an alveolar image on the chest x-ray, and a high white cell count are synonymous with bacterial pneumonia in only 40 to 60% of the cases. PRIMARY AND SECONDARY INFECTION: Using reliable microbiological methodology is has been possible to demonstrate that the causal germs of primary infections disappear by day 3 of an adapted treatment but that early secondary infection occurs in 14% of the cases. PROSPECTS FOR PROGRESS: An open multicentric randomized study is being conducted in France to compare 7 day versus 14 day treatment against identified germs (irrespective of the strain isolated) using reliable microbial sampling techniques.

Invasive and noninvasive strategies for management of suspected ventilator-associated pneumonia. A randomized trial

BACKGROUND

Optimal management of patients who are clinically suspected of having ventilator-associated pneumonia remains open to debate.

OBJECTIVE

To evaluate the effect on clinical outcome and antibiotic use of two strategies to diagnose ventilator-associated pneumonia and select initial treatment for this condition.

DESIGN

Multicenter, randomized, uncontrolled trial.

SETTING

31 intensive care units in France.

PATIENTS

413 patients suspected of having ventilator-associated pneumonia.

INTERVENTION

The invasive management strategy was based on direct examination of bronchoscopic protected specimen brush samples or bronchoalveolar lavage samples and their quantitative cultures. The noninvasive ("clinical") management strategy was based on clinical criteria, isolation of microorganisms by nonquantitative analysis of endotracheal aspirates, and clinical practice guidelines.

MEASUREMENTS

Death from any cause, quantification of organ failure, and antibiotic use at 14 and 28 days.

RESULTS

Compared with patients who received clinical management, patients who received invasive management had reduced mortality at day 14 (16.2% and 25.8%; difference, -9.6 percentage points [95% CI, -17.4 to -1.8 percentage points]; P = 0.022), decreased mean Sepsis-related Organ Failure Assessment scores at day 3 (6.1+/-4.0 and 7.0+/-4.3; P = 0.033) and day 7 (4.9+/-4.0 and 5.8+/-4.4; P = 0.043), and decreased antibiotic use (mean number of antibiotic-free days, 5.0+/-5.1 and 2.2+/-3.5; P < 0.001). At 28 days, the invasive management group had significantly more antibiotic-free days (11.5+/-9.0 compared with 7.5+/-7.6; P < 0.001), and only multivariate analysis showed a significant difference in mortality (hazard ratio, 1.54 [CI, 1.10 to 2.16]; P = 0.01).

CONCLUSIONS

Compared with a noninvasive management strategy, an invasive management strategy was significantly associated with fewer deaths at 14 days, earlier attenuation of organ dysfunction, and less antibiotic use in patients suspected of having ventilator-associated pneumonia.

Prevalence, etiologies and outcome of the acute respiratory distress syndrome among hypoxemic ventilated patients. SRLF Collaborative Group on Mechanical Ventilation. Société de Réanimation de Langue Française

OBJECTIVE

To evaluate the prevalence and outcome of the acute respiratory distress syndrome (ARDS) among patients requiring mechanical ventilation.

DESIGN

A prospective, multi-institutional, initial cohort study including 28-day follow-up.

SETTINGS

Thirty-six French intensive care units (ICUs) from a working group of the French Intensive Care Society (SRLF).

PATIENTS

All the patients entering the ICUs during a 14-day period were screened prospectively. Hypoxemic patients, defined as having a PaO(2)/FIO(2) ratio (P/F) of 300 mmHg or less and receiving mechanical ventilation, were classified into three groups, according to the Consensus Conference on ARDS: group 1 refers to ARDS (P/F: 200 mmHg or less and bilateral infiltrates on the chest X-ray); group 2 to acute lung injury (ALI) without having criteria for ARDS (200 < P/F </= 300 mmHg and bilateral infiltrates) and group 3 to patients with P/F of 300 mmHg or less but having exclusion criteria from the previous groups.

RESULTS

Nine hundred seventy-six patients entered the ICUs during the study period, 43 % of them being mechanically ventilated and 213 (22 %) meeting the criteria for one of the three groups. Among all the ICU admissions, ARDS, ALI and group 3 patients amounted, respectively, to 6.9 % (67), 1.8 % (17) and 13.3 % (129) of the patients, and represented 31.5 %, 8.1 % and 60.2 % of the hypoxemic, ventilated patients. The overall mortality rate was 41 % and was significantly higher in ARDS patients than in the others (60 % vs 31 % p < 0.01). In group 3, 42 patients had P/F less than 200 mmHg associated with unilateral lung injury; mortality was significantly lower (40.5 %) than in the ARDS group. In the whole group of hypoxemic, ventilated patients, septic shock and severity indices but not oxygenation indices were significantly associated with mortality, while the association with immunosuppression revealed only a trend (p = 0.06).

CONCLUSIONS

In this survey we found that very few patients fulfilled the ALI non-ARDS criteria and that the mortality of the group with ARDS was high.

Hospital-acquired pneumonia: methicillin resistance and intensive care unit admission

Although epidemiologic investigations of hospital-acquired pneumonia have certain intrinsic limitations because of the heterogeneity of the study populations, the difficulties in making a clinical diagnosis of nosocomial pneumonia, and the need for better microbiologic assays, recent studies have provided new and important data concerning the role of Staphylococcus aureus in this disease. This pathogen has now been identified as the most frequent cause of nosocomial pneumonia in hospitals in both Europe and the United States among patients in general hospital units as well as in the intensive care unit (ICU). Patients who have been treated with mechanical ventilation are at especially high risk for S. aureus pneumonia. The incidence of nosocomial pneumonia related to methicillin-resistant S. aureus (MRSA) has increased in recent years in many countries, especially among patients in the ICU. Because hospitalized patients with suspected nosocomial pneumonia often have many risk factors for MRSA infection, it seems advisable to include coverage of MRSA in the initial therapeutic regimen for these patients until MRSA infection is excluded.

Risk factors and outcome of nosocomial infections: results of a matched case-control study of ICU patients

Intensive-care-unit (ICU) patients are at risk for both acquiring nosocomial infection and dying, and require a high level of therapy whether infection occurs or not. The objective of the present study was to precisely define the interrelationships between underlying disease, severity of illness, therapeutic activity, and nosocomial infections in ICU patients, and their respective influences on these patients' outcome. In a 10-bed medical ICU, we conducted a case-control study with matching for initial severity of illness, with daily monitoring of severity of illness and therapeutic activity scores, and with analysis of the contribution of nosocomial infections to patients' outcomes. Forty-one cases of patients who developed nosocomial infections during a 1-yr period were paired with 41 controls without nosocomial infection according to three criteria: age (+/- 5 yr), Acute Physiology and Chronic Health Evaluation II (APACHE II) score (+/- 5 points), and duration of exposure to risk. Successful matching was achieved for 118 of 123 (96%) variables. Neurologic failure on the third day after ICU admission was the sole independent risk factor for nosocomial infection (adjusted odds ratio [OR]: 1.34; 95% confidence interval [CI]: 1.09 to 1.64; p = 0.007). Unlike control patients, case patients showed no clinical improvement and required a high level of therapeutic activity between ICU admission and the day of infection. Mortality attributable to nosocomial infection was 44%. Excess length of stay and duration of antibiotic treatment attributable to nosocomial infection were 14 d and 10 d, respectively. Attributable therapeutic activity as measured with the Therapeutic Intervention Scoring System (TISS) and Omega score was 368 and 233 points, respectively. Such consequences were observed in patients who developed multiple infections. These findings suggest that a persistent high level of therapeutic activity and persistent impaired consciousness are risk factors for nosocomial infections in ICU patients. These infections are responsible for excess mortality, prolongation of stay, and excess therapeutic activity resulting in important cost overruns for health-care systems.

Colonization by Acinetobacter baumanii in intensive-care-unit patients

We prospectively studied the value of systematic rectal swabs performed for the detection of colonization and the prediction of infections by Acinetobacter baumanii in 751 consecutive patients admitted to five intensive-care units (ICUs) over an 8-month period. Gastrointestinal tract colonization was found in 8.7% of ICU admissions. The positive and negative predictive values of rectal swabs for the detection of subsequent infection were 17% and 99%, respectively. Sensitivity and specificity were 55% and 93%, respectively. We also determined the comparative values of rectal or nasal swabs and skin cultures for the detection of A baumanii colonization in 25 patients already colonized or infected with A baumanii. The combination of rectal and nasal swabs was positive in 20 (80%) of 25. The results of the present study suggest that detection of gastrointestinal tract A baumanii colonization is not an accurate predictor of subsequent A baumanii infection and that combined rectal and nasal swabs might be used for the detection of A baumanii colonization in ICU patients.

Determination of total effective vascular compliance in patients with sepsis syndrome

Changes in capacitance vessels have important consequences on cardiac filling pressure and fluid volume distribution in patients with sepsis syndrome. Vascular compliance may be evaluated from the slope of the relationship between changes in total blood volume (deltaTBV) and changes in central venous pressure (deltaCVP) during acute volume expansion (450 ml of gelatin fluid over 6 min), i.e., from the deltaTBV/deltaCVP ratio. The mean ratio (ml x mm Hg-1 x kg-1) was 2.03 +/- 0.21 in control subjects, 1.43 +/- 0.25 in mechanically ventilated patients without sepsis syndrome, and 0.94 +/- 0.24 in mechanically ventilated patients with sepsis syndrome (p < 0.0001 versus the other two groups). Based on echocardiographic determinations, cardiac performance was constantly found within the normal range (cardiac output ranged from 5.6 +/- 1.2 to 6.7 +/- 2.0 L/min in nonseptic patients from 6.8 +/- 1.9 to 7.8 +/- 2.2 in septic patients). Effective compliance of the total vascular bed is therefore reduced in patients with sepsis syndrome, independently of the hemodynamic modifications due to mechanical ventilation.

Improvement of internal jugular vein cannulation using an ultrasound-guided technique

OBJECTIVE

To determine whether ultrasound guidance can help operators to improve the results of jugular vein access in the ICU.

DESIGN

Prospective, randomized study.

SETTING

General Intensive Care Unit of a University Hospital.

PATIENTS

Seven-nine patients were assigned to internal jugular vein cannulation using anatomical landmarks alone (control group, n = 42) or with ultrasound guidance (ultrasound group, n = 37).

INTERVENTION

All cannulations were performed by junior house staff under the direct supervision of a senior physician. In the ultrasound group, an ultrasonography (7.5 MHz) was used and the transducer was covered by a sterile sheath. The placement and direction of the cannulating needle were determined on the ultrasound image.

MEASUREMENTS AND RESULTS

Internal jugular vein cannulation was successful in 37/37 (100%) patients in the ultrasound group and in 32/42 patients (76%) in the control group (p < 0.01). Average access time was longer in the control group (235 +/- 408 s vs 95 +/- 174 s, p = 0.06) and carotid artery puncture occurred in five patients in each group (p = 0.83). Jugular cannulation was successful at the first attempt in 26% in the control group and 43% in the ultrasound group (p = 0.11). Thirty-two patients (86%) in the ultrasound group and 23 patients (55%) in the control group (p < 0.05) were cannulated within 3 min. The cannula could therefore not be inserted within 3 min in 19 patients (45%) in the control group. Failure was explained by thrombosis (n = 1), small caliber of the internal jugular vein (< 5 mm, n = 3), abnormal vascular relations (n = 3). Among the ten primary failures of cannulation, an internal jugular vein catheter was able to be inserted in four cases by an experienced physician on the side initially selected and with ultrasound guidance in two cases. The catheter was inserted into the contralateral internal jugular vein under ultrasound guidance in the remaining four cases.

CONCLUSION

Ultrasound guidance improved the success rate of jugular vein cannulation in ICU patients. Our results suggest that ultrasound guidance should be used when the internal jugular vein has not been successfully cannulated within 3 min by the external landmark-guided technique.

[Prevention of acquired pneumonia during artificial ventilation (excluding the use of anti-infectious agents)]

Nosocomial pneumonia remains a serious complication which occurs in patients who are artificially ventilated; as neither frequency nor important sequelae have altered recently inspite of the progress which has been achieved both with diagnosis and treatment. Preventative measures ought to be developed and realistically assessed before their introduction. Today it is indispensable to measure the impact of these measures, whether they have been previously or recently proposed by therapeutic trials. The current techniques proposed to prevent the appearance of nosocomial pneumonia are integrated in the usual conventional group of measures in the struggle against nosocomial infection which rests predominantly on standard approaches to hospital hygiene. These may be more specifically directed at good practical measures for the care of the ventilated patient. Regular toilet to the digestive and respiratory pathway, care of the ventilator material, absence of the changing of ventilation tubing during the stay. A certain number of measures are specifically suggested to prevent pneumonias: they have been imperfectly evaluated in clinical practice and remain controversial. Thus selective decontamination of the digestive system has not been dealt with her but also the sitting position, the utilisation of turning or oscillating beds, the continuous aspiration of oropharyngeal secretions or the use of Sucralfate as a means of prevention stress ulcers. Today, and until a complete evaluation of different techniques, the prevention of acquired pneumopathy during artificial ventilation rests above all on extremely simple measures; these cost little and are essentially meticulous care of the upper respiratory and digestive apparatus, to tracheal aspiration and physiotherapy which assure effective drainage and secretions, the use of the semi-sitting position, a well positioned gastric tube, in other words, basic care of the ventilated patient of a very good quality.

[Nosocomial pneumonia in intensive care units]

Nosocomial pneumonia is associated with substantial morbidity and mortality. Patients treated with mechanical ventilation have the highest risk for developing this intensive care unit acquired infection. Gram-negative bacilli are the predominant organisms responsible for pneumonia in this setting. However, Staphylococcus aureus has recently emerged as a significant isolate. Nosocomial pneumonia is difficult to diagnose clinically in ventilated patients because fever, lung infiltrate on chest X-ray, leukocytosis are frequent in severely ill patients under mechanical ventilation whatever lung infection is present or not and because lower respiratory tract of such patients is colonized by potentially pathogenic bacteria independently of the presence of true lung infection; thus, different diagnostic strategies are proposed. Our personal bias is that using bronchoscopic techniques to obtain bronchoalveolar lavage and protected-brush specimens permits us to devise a therapeutic strategy that is superior to one based only on clinical evaluation. Measures for prevention of nosocomial infection are essential to decrease the incidence of nosocomial pneumonia and the emergence of multiresistant pathogens.

Long-term outcome and quality of life of patients requiring multidisciplinary intensive care unit admission after cardiac operations

Patients with organ failure or severe infection after cardiac operations may require prolonged stays in the intensive care unit. This study examined long-term mortality and determined quality of life for surviving patients in this group. This observational cohort study was conducted at Bichat Hospital, Paris, an academic tertiary care center. The study group consisted of 116 consecutive patients who underwent cardiac operations and were transferred to the multidisciplinary intensive care unit between January 1986 and December 1987. Patients referred for mediastinitis were automatically excluded. Respiratory failure (88.8%) and hemodynamic instability (81.9%) were the main causes of transfer; an infection was present in 23.3% of patients at entry into the intensive care unit. Twenty-seven patients (23.3%) died in the intensive care unit. Presurgical New York Heart Association functional class, postoperative bacteremia before admission to the intensive care unit, and severity of illness on admission to the intensive care unit were independent predictors of death in the intensive care unit. After an average follow-up of 81 months (range 70 to 93 months), 69% of the patients alive at transfer from the intensive care unit were still alive. Preoperative New York Heart Association functional class was the only long-term independent prognostic factor. Quality of life, as evaluated by the Nottingham Health Profile, was good for more than 70% of the survivors and was not influenced by any recorded variables, with the exception of age.

Diagnostic and therapeutic implications of transesophageal echocardiography in medical ICU patients with unexplained shock, hypoxemia, or suspected endocarditis

OBJECTIVE

To evaluate the diagnostic and therapeutic implications of transesophageal echocardiography (TEE) in intensive care patients.

DESIGN

Comparative study.

SETTING

A 10-bed general intensive care unit.

PATIENTS

Between 1 January 1992 and 31 May 1993, 61 patients prospectively identified with shock (n = 14), severe, unexplained hypoxemia (Partial pressure of oxygen in arterial blood/fractional inspired oxygen < 200) (n = 31), or suspected endocarditis (n = 16) underwent a TEE examination to supplement transthoracic echocardiography (TTE) examination.

INTERVENTIONS

The results of each TEE examination were compared with the clinical findings and TTE data. TEE examinations were classified as follows: 0, TEE results were similar to TTE results; 00, TEE examination resulted in exclusion of suspected abnormalities; 1, TEE revealed a new but minor diagnosis compared to the TTE diagnosis; 2, TEE revealed a new major diagnosis not requiring a change of treatment; 3, TEE results revealed a new major diagnosis requiring an immediate change of treatment.

RESULTS

Intraobserver reliability of the TEE classification was confirmed by a 100% concordance and interobserver reliability was evaluated as an 84% concordance. Results of the TEE classification were: class 0, n = 21 (34%); class 00, n = 13 (21%); class 1, n = 7 (12%); class 2, n = 8 (13%); class 3, n = 12 (20%). Therapeutic implications of TEE in class 3 patients were cardiac surgery in 5 patients (2 cases of acute mitral regurgitation, 2 valvular abscesses, and 1 hematoma compressing the left atrium), discontinuation of positive end-expiratory pressure in 1 ventilated patient with an atrial septal defect, weaning off mechanical ventilation in 1 patient with an atrial septal defect, prescription of antimicrobial therapy in 3 patients with endocarditis, and prescription of anticoagulant therapy in 2 patients with left atrial thrombus. No difficulty inserting the transducer was observed in any of the 61 patients studied. The only noteworthy complication was a case of spontaneously resolving atrial fibrillation.

CONCLUSION

TEE is safe and well tolerated and is useful in the management of patients in the intensive care unit with shock, unexplained and severe hypoxemia, or suspected endocarditis when TTE is inconclusive.

Mortality due to ventilator-associated pneumonia or colonization with Pseudomonas or Acinetobacter species: assessment by quantitative culture of samples obtained by a protected specimen brush

Ventilator-associated pneumonia (VAP) due to multiresistant pathogens is associated with a high death rate. We analyzed the relationship between VAP due to Pseudomonas or Acinetobacter species and death by comparing the outcomes for patients colonized with these pathogens (bacterial counts of < 10(3) cfu/mL) with those for patients with pneumonia due to these pathogens (bacterial counts of > or = 10(3) cfu/mL). Samples were obtained systematically with a protected specimen brush when pneumonia was suspected. Clinical characteristics at admission to our intensive care unit and clinical features at the time of suspicion of VAP were not significantly different between colonized patients and those with VAP. Mortality rates were 29% among colonized patients and 73% among patients with VAP (P < .001). These results demonstrate a relationship between a high mortality rate and the development of pneumonia due to multiresistant, nonfermenting, gram-negative bacilli ( > or = 10(3) cfu/mL) in the lower airways of patients receiving ventilatory support.

Diagnosis of pulmonary infections in mechanically ventilated patients

The optimal management strategy for ventilator-dependent patients who develop symptoms suggestive of lung infection remains controversial. Proponents of the empirical approach prefer to treat most patients with fever and pulmonary infiltrates with one or more new antibiotics, even if it may be difficult (1) to determine whether pneumonia has developed in such patients, (2) in case of infection, to precisely identify the responsible microorganisms and thereby select the optimal antimicrobial treatment, and (3) to avoid resorting to broad-spectrum drug coverage in patients without true infection. Our personal bias is that using bronchoscopic techniques to obtain protected specimen brush and bronchoalveolar lavage specimens from the affected area in the lung permits to devise a therapeutic strategy superior to the one based only on clinical evaluation. These bronchoscopic techniques, when they are performed before new antibiotics are administered, enable physicians to identify most patients who need immediate treatment and select optimal therapy, in a manner that is safe and well tolerated by patients. Furthermore, they frequently permit the clinician to withhold antimicrobial treatment in patients without infection, minimizing the risk of the emergence of resistant microorganisms in the intensive care unit. In patients with clinical evidence of severe sepsis, the initiation of antibiotic therapy should not, however, be delayed while awaiting bronchoscopy, and patients should be given immediate treatment with antibiotics. In that case, "simplified" non-bronchoscopic diagnostic procedures might allow obtaining reliable distal pulmonary secretions for quantitative cultures on a 24-hour basis just before the initiation of a new antimicrobial therapy.

Severe exacerbations of COPD patients: the role of pulmonary infections

Infection is usually considered the main cause of acute exacerbation in chronic obstructive pulmonary disease (COPD). However, uncertainty persists concerning the exact role of bacterial and viral infection in this setting because of the confusing and conflicting data on the role of tracheobronchial microflora and the usefulness of antibiotics in treating this disease. Most COPD patients have evidence of lower respiratory tract chronic bacterial colonization during remission periods as well as during acute exacerbations. This is evidenced by using microbiological analysis of secretions, which reflect all the respiratory tract (sputum), the lower respiratory tract (transtracheal aspiration), or the distal respiratory tract (protected specimen brush). Potentially pathogenic organisms can be recovered from the respiratory tract secretions of virtually all patients with COPD at some time during the course of their disease. Absence of difference in isolation of potentially pathogenic organisms between remission periods and acute exacerbations suggests that bacterial infection is probably not the predominant cause of acute exacerbations in COPD. In contrast, data indicate that the association between viral infections and acute exacerbations is clearer than that with bacteria, affecting probably more than 20% of cases. The role of antibiotic therapy in acute exacerbations of COPD remains controversial. (1) Clearly, antibiotic therapy is urgently required in COPD patients with pneumonia. (2) Review of the conflicting results of studies evaluating the role of antibiotic therapy for preventing acute exacerbations suggests that there is no clear-cut rationale for prophylactic treatment of infection for all patients with COPD; it seems, however, that such treatment may be of some use in highly selected patients, such as those with many exacerbations in the winter. (3) Similarly, data are conflicting concerning the curative use of antibiotic therapy, with some studies suggesting acceleration of recovery, prevention of acute deterioration, and longer period of freedom from recurrent exacerbations; conversely many patients recover from exacerbations without resorting to an antibiotic. Unfortunately, no clear data identify patients who could benefit from antibiotic treatment, probably justifying most clinicians' choice to treat acute exacerbations as infectious events.

Nosocomial pneumonia and mortality among patients in intensive care units

OBJECTIVE

To evaluate the role that nosocomial pneumonia plays in the outcome of intensive care unit (ICU) patients.

DESIGN

Cohort study.

SETTING

Medical ICU, Hôpital Bichat, Paris, France, an academic tertiary care center.

PATIENTS

A total of 1978 consecutive patients admitted to the ICU for at least 48 hours.

MAIN OUTCOME MEASURES

Various parameters known to be strongly associated with death of ICU patients were recorded: age, location before admission to the ICU, diagnostic categories, Acute Physiology and Chronic Health Evaluation (APACHE) II score, Simplified Acute Physiologic Score, McCabe score, number and type of dysfunctional organs, and the development of nosocomial bacteremia and nosocomial urinary tract infection. These variables and the presence or absence of nosocomial pneumonia were compared between survivors and nonsurvivors and entered into a stepwise logistic regression model to evaluate their independent prognostic roles.

RESULTS

Nosocomial pneumonia developed in 328 patients (16.6%) whose mortality was 52.4% compared with 22.4% for patients without ICU-acquired pneumonia (P < .001), APACHE II score (odds ratio [OR] = 1.08; 95% confidence interval [CI], 1.06 to 1.10; P < .001), number of dysfunctional organs (OR = 1.54; 95% CI, 1.36 to 1.74; P < .001), nosocomial pneumonia (OR = 2.08; 95% CI, 1.55 to 2.80; P < .001), nosocomial bacteremia (OR = 2.51; 95% CI, 1.78 to 3.55; P < .001), ultimately or rapidly fatal underlying disease (OR = 1.76; 95% CI, 1.38 to 2.25; P < .001), and admission from another ICU (OR = 1.30; 95% CI, 1.01 to 1.68; P =.04) were significantly associated with mortality.

CONCLUSION

These data suggest that, in addition to the severity of underlying medical conditions and nosocomial bacteremia, nosocomial pneumonia independently contributes to ICU patient mortality.

Diagnosis and treatment of nosocomial pneumonia in patients in intensive care units

The optimal management strategy for ventilator-dependent patients who develop symptoms suggestive of lung infection remains controversial. Our personal bias is that using bronchoscopic techniques to obtain protected-brush and bronchoalveolar lavage specimens from the affected area in the lung permits physicians to devise a therapeutic strategy that is superior to one based only on clinical evaluation. These bronchoscopic techniques, when they are performed before new antibiotics are administered, enable physicians to identify most patients who need immediate treatment and to select optimal therapy, in a form that is safe and well tolerated by patients. Furthermore, they frequently permit physicians to withhold antimicrobial treatment from patients without infection, thereby minimizing the risk of emergence of resistant microorganisms in the intensive care unit. Despite many advances in antimicrobial therapy, successful treatment of patients with nosocomial pneumonia remains a complex undertaking, and ultimately further trials will be needed to clarify the optimal duration of treatment and the circumstances in which monotherapy can be safely used.

Evaluation of bronchoscopic techniques for the diagnosis of nosocomial pneumonia

To compare the usefulness of specimens obtained by bronchoalveolar lavage (BAL) and using a protected specimen brush (PSB) in the diagnosis of nosocomial pneumonia, both procedures were performed via fiberoptic bronchoscopy just after death in a series of 20 ventilated patients who had not developed pneumonia before the terminal phase of their disease and who had no recent changes in antimicrobial therapy. These results were compared with both histologic and microbiologic postmortem lung features in the same area. The total number of bacteria obtained by culture of lung segments and the latters' histologic grade were closely correlated (rho = 0.79, p < 0.0001). PSB and BAL quantitative culture results were strongly correlated with lung tissue values (rho = 0.67 and 0.75, respectively; p < 0.0001). Using discriminative values of > or = 10(3) and > or = 10(4) bacteria/ml to define positive PSB and BAL cultures, respectively, these techniques identified lung segments yielding > or = 10(4) bacteria/g tissue with sensitivities of 82 and 91% and specificities of 89 and 78%, respectively. Moreover, upon direct observation, the percentage of BAL cells containing intracellular bacteria was closely correlated with the total number of bacteria obtained from corresponding lung samples (p < 0.001). These findings indicate that bronchoscopic PSB and BAL samples very reliably identify both qualitatively and quantitatively microorganisms present in lung segments with bacterial pneumonia, even when the infection develops as a superinfection in a patient already receiving antimicrobial treatment for several days.

Nosocomial acquisition of multiresistant Acinetobacter baumannii: risk factors and prognosis

To identify risk factors for and prognostic indicators of the nosocomial acquisition of multiresistant Acinetobacter baumannii in an intensive care unit, we prospectively studied 40 patients: 13 who were infected with this organism and 27 who were colonized. Isolates were identified by pulsed-field gel electrophoresis; the infected/colonized patients were compared with 348 noninfected, noncolonized patients by logistic regression analysis and with matched historical controls in a cohort study. The severity of illness (evaluated by the APACHE II score; P < .05) and previous infection (P < .001) were retained as independent risk factors for acquiring A. baumannii. Logistic regression analysis selected a high APACHE II score (P < .01) and the acquisition of A. baumannii (P < .01) as factors independently associated with death. The acquisition of A. baumannii was associated not only with high mortality but also with a length of stay on the intensive care unit in excess of that due to the underlying disease alone; specifically, the attributable mortality was 25%, with a risk ratio for death of 2.0 (95% confidence interval, 1.11-3.62), and the duration of stay for infected/colonized patients was 10.3 days longer than that for controls (P < .001).

Mortality attributable to nosocomial infections in the ICU

Although a direct relationship between nosocomial infection and mortality in intensive care unit (ICU) patients has not always been demonstrated formally, it is possible to conclude that nosocomial infections increase the risk of death in critically ill patients. A more precise analysis indicates that: 1) this effect is highly probable for pneumonia, doubtful for bacteremia, and uncertain for urinary tract infection; 2) risk increases with duration of stay in the ICU; 3) bacterial etiology modifies the risk; and 4) this effect is stronger in less severely ill patients, probably because the severity of underlying disease remains the most significant factor.

High levels of interleukin-8 in the blood and alveolar spaces of patients with pneumonia and adult respiratory distress syndrome

There is ample experimental evidence that polymorphonuclear neutrophils (PMN) play a critical role in the pathogenesis of the adult respiratory distress syndrome (ARDS). Since interleukin-8 (IL-8) is a strong chemotactic factor for PMN, we measured IL-8 levels in plasma and bronchoalveolar lavage (BAL) fluid of 18 patients, 12 with ARDS and 6 with severe pneumonia uncomplicated by ARDS, all of whom had an increased number of PMN in BAL fluid. Seven healthy subjects served as controls. We found elevated levels of IL-8 in the alveolar spaces of all patients tested. Elevated BAL IL-8 levels were related to a fatal outcome and the presence of shock and correlated with a general clinical severity index (simplified acute physiological score). BAL fluid levels of IL-8 were significantly higher in patients with ARDS than in patients with pneumonia. In plasma, IL-8 levels were increased similarly in all patients and did not correlate with survival or the presence of shock. The BAL fluid-to-plasma ratio of IL-8 was significantly greater than that of tumor necrosis factor alpha, indicating higher local production of IL-8. Moreover, the presence of a primed subpopulation of blood PMN with respect to H2O2 production indicates that IL-8 may contribute to the neutrophil-mediated process in the pathogenesis of ARDS and pneumonia.

Pilot study of cardiopulmonary risk from pentoxifylline in adult respiratory distress syndrome

Neutrophils and cytokines are directly involved in the pathophysiology of adult respiratory distress syndrome (ARDS). Pentoxifylline (PTX) has been shown in vitro to protect against the inflammatory effects of neutrophils and cytokines. The same protective effects have been demonstrated on animal models of lung injury. These results suggested that PTX might be useful in patients with ARDS. The cardiopulmonary effects of large doses of PTX were evaluated in a pilot study performed in six patients with severe ARDS. PTX was administered with an initial 1-mg/kg bolus, followed by infusion of 1.5 mg/kg/h over 6 h. No significant change was observed in the gas exchange and hemodynamic parameters, except for a 10 percent increase in the heart rate during the infusion period. Our results demonstrate that large doses of PTX induced only minor hemodynamic changes without worsening in pulmonary gas exchange. Further studies are warranted to evaluate human safety and ultimately the effectiveness of PTX in the treatment of ARDS.

Characterization of intensive care unit patients using a model based on the presence or absence of organ dysfunctions and/or infection: the ODIN model

OBJECTIVE

To evaluate the sensitivity, specificity and overall accuracy of a model based on the presence or absence of organ dysfunctions and/or infection (ODIN) to predict the outcome for intensive care unit patients.

DESIGN

Prospective study.

SETTING

General intensive care unit in a university teaching hospital.

PATIENTS

1070 consecutive, unselected patients.

INTERVENTIONS

There were no interventions.

MEASUREMENTS AND MAIN RESULTS

We recorded within the first 24 h of admission the presence or absence of dysfunction in 6 organ systems: respiratory, cardiovascular, renal, hematologic, hepatic and neurologic, and/or infection (ODIN) in all patients admitted to our ICU, thus establishing a profile of organ dysfunctions in each patient. Using univariate analysis, a strong correlation was found between the number of ODIN and the death rate (2.6, 9.7, 16.7, 32.3, 64.9, 75.9, 94.4 and 100% for 0, 1, 2, 3, 4, 5, 6 and 7 ODIN, respectively; (p < 0.001). In addition, the highest mortality rates were associated with hepatic (60.8%), hematologic (58.1%) and renal (54.8%) dysfunctions, and the lowest with respiratory dysfunction (36.5%) and infection (38.3%). For taking into account both the number and the type of organ dysfunction, a logistic regression model was then used to calculate individual probabilities of death that depended upon the statistical weight assigned to each ODIN (in the following order of descending severity: cardiovascular, renal, respiratory, neurologic, hematologic, hepatic dysfunctions and infection). The ability of this severity-of-disease classification system to stratify a wide variety of patients prognostically (sensitivity 51.4%, specificity 93.4%, overall accuracy 82.1%) was not different from that of currently used scoring systems.

CONCLUSIONS

These findings suggest that determination of the number and the type of organ dysfunctions and infection offers a clear and reliable method for characterizing ICU patients. Before a widespread use, this model requires to be validated in other institutions.

Nosocomial pneumonia in ventilated patients: a cohort study evaluating attributable mortality and hospital stay

PURPOSE

Although nosocomial pneumonia is a common problem in intubated and ventilated patients, previous studies have not clearly demonstrated that nosocomial pneumonia actually results in increased mortality or prolongs hospitalization of these patients. In an attempt to answer these questions, we have performed a cohort study in which patients who developed nosocomial pneumonia and control subjects were carefully matched for the severity of underlying illness and other important variables.

PATIENTS AND METHODS

Case patients were 48 ventilated patients with nosocomial pneumonia identified on the basis of results of protected specimen brush quantitative culture and identification of intracellular organisms in cells recovered by bronchoalveolar lavage. For matching cases and their respective controls, the following variables were used: age (+/- 5 years), Simplified Acute Physiologic Score (+/- 3 points), indication for ventilatory support, date of admission, and duration of exposure to risk.

RESULTS

Successful matching was achieved for 222 of 240 (92.5%) variables. The mortality rate in cases was 26 of 48 (54.2%) compared with 13 of 48 (27.1%) in controls. The attributable mortality was 27.1% (95% confidence interval [CI], 8.3% to 45.9%; p < 0.01) and the risk ratio for death was 2.0 (95% CI, 1.61 to 2.49). The mean length of stay was 34 days for cases and 21 days for controls (p < 0.02). In the case of pneumonia due to Pseudomonas or Acinetobacter species, the mortality rate was 71.4%, the attributable mortality was 42.8% (95% CI, 14.5% to 69.0%), and the risk ratio was 2.50 (95% CI, 1.31 to 4.61).

CONCLUSION

Pneumonias occurring in ventilated patients, especially those due to Pseudomonas or Acinetobacter species, are associated with considerable mortality in excess of that resulting from the underlying disease alone, and significantly prolong the length of stay in the intensive care unit.

Evaluation of clinical judgment in the identification and treatment of nosocomial pneumonia in ventilated patients

To evaluate the accuracy of clinical judgment in the diagnosis and treatment of nosocomial pneumonia in ventilated patients, we studied 84 patients suspected of having nosocomial pneumonia because of the presence of a new pulmonary infiltrate and purulent tracheal secretions. We prospectively evaluated the accuracy of diagnostic predictions and therapeutic plans independently formulated by a team of physicians aware of all clinical, radiologic and laboratory data, including the results of Gram-stained bronchial aspirates. Definite (n = 51) or probable (n = 33) diagnoses could be established in all patients by strict histopathologic and/or bacteriologic criteria. Only 27/84 patients were diagnosed as having pneumonia. Organisms responsible for pneumonias were identified by quantitative cultures of samples obtained using a protected specimen brush or pleural fluid cultures. Four hundred eight predictions were made for the 84 studied patients. Clinical diagnoses for patients subsequently diagnosed as having pneumonia were accurate in 81/131 cases (62 percent). Furthermore, only 43/131 (33 percent) therapeutic plans proposed for these patients represented effective therapy. Common causes of inappropriate treatment included failure to diagnose pneumonia (50 plans), failure to effectively treat highly resistant organisms (21 plans), and failure to treat all organisms in cases of polymicrobial pneumonia (14 plans). Therapeutic plans formulated for patients without pneumonia included the unnecessary use of antibiotics in 45/277 cases (16 percent). These findings indicate that the use of clinical criteria alone does not permit the accurate diagnosis of nosocomial pneumonia in ventilated patients, and commonly results in inappropriate or inadequate antibiotic therapy for these patients.

Analysis of vancomycin entry into pulmonary lining fluid by bronchoalveolar lavage in critically ill patients

Vancomycin penetration into the fluid lining the epithelial surface of the lower respiratory tract was studied by performing fiberoptic bronchoscopy with bronchoalveolar lavage on 14 critically ill, ventilated patients who had received the drug for at least 5 days. The apparent volume of epithelial lining fluid (ELF) recovered by bronchoalveolar lavage was determined by using urea as an endogenous marker. Vancomycin levels in ELF ranged from 0.4 to 8.1 micrograms/ml (mean, 4.5 micrograms/ml), while the mean simultaneous level of the drug in plasma was 24 micrograms/ml (range, 9 to 37.4 micrograms/ml). There was a significant relationship (r = 0.64, P < 0.02) between vancomycin levels in plasma and those in ELF, with a correlation whose slope (0.15) indicated that the blood-to-ELF ratio of drug penetration was 6:1. Using the albumin concentration in ELF as a marker of lung inflammation, we found that vancomycin penetration was higher in patients with ELF albumin values of > or = 3.4 mg/ml than in patients with normal values (< 3.4 mg/ml) (P < 0.02). These results suggest that the vancomycin distribution includes the ELF of the lower respiratory tract at a concentration that is dependent upon the levels in blood and the alveolar capillary membrane protein permeability. These concentrations were well above the MICs for most staphylococci and enterococci.

Follow-up protected specimen brushes to assess treatment in nosocomial pneumonia

To prospectively determine the bacteriologic and clinical efficacy of antimicrobial therapy for nosocomial bacterial pneumonia selected based upon information provided by cultures of protected specimen brush (PSB) samples obtained during bronchoscopy, 76 consecutive patients with ventilator-associated pneumonia were studied using follow-up quantitative PSB cultures obtained after 3 days of treatment. Of the 173 microorganisms initially present in the PSB samples, only 11 (6%) were not eradicated by antimicrobial therapy, including three recovered at high (> or = 10(3) cfu/ml) concentrations. Thirty-two emerging pathogens, including nine at high concentrations, were also detected; 26 of them (81%) were resistant to the initial antibiotics administered. Of the 76 patients included in the study, cultures of follow-up PSB samples identified 51 in whom the infection site in the lung was completely sterilized, 16 with low-grade infection, and only nine with persistent high-grade infection. Analysis of clinical outcome within the 15 days after the initiation of antimicrobial therapy demonstrated clinical improvement in 62 of 67 (93%) patients in whom the site of infection was contained by treatment as compared with four of 9 (44%) patients with persistent high-grade infection (p < 0.01). These data suggest that appropriate antimicrobial therapy for ventilator-associated pneumonia results in the control of the initial infection in 88% of the patients. However, an early superinfection caused by multiresistant pathogens can occur in a small subset of these patients. When follow-up PSB cultures were negative, an improved outcome was noted.

Subpopulation of hyperresponsive polymorphonuclear neutrophils in patients with adult respiratory distress syndrome. Role of cytokine production

To gain further insight into the pathogenesis of the adult respiratory distress syndrome (ARDS), we studied possible relationships among the activation status of circulating polymorphonuclear neutrophils (PMN), cytokine levels, and the severity of lung injury in 31 patients: 15 with ARDS, nine with severe pneumonia uncomplicated by ARDS, and seven mechanically ventilated with neither ARDS nor pneumonia. Nine healthy subjects served as controls. Using flow cytometry, we identified a subpopulation of PMN with an increased capacity to generate hydrogen peroxide after stimulation ex vivo in all three patient groups; significantly higher values were found in those with ARDS. The PMN stimulation index, a reflection of the degree of hyperresponsiveness, correlated with elevated levels of tumor necrosis factor-alpha (TNF alpha) in plasma, and both spontaneous and lipopolysaccharide-induced TNF alpha production by cultured monocytes. These biologic expressions of PMN activation and cytokine generation both correlated with indices of the severity of lung injury, but not with the overall clinical severity. In contrast, IL-6 and IL-1 beta showed little or no relationship with either the degree of lung injury or PMN hyperresponsiveness. We conclude that TNF-alpha-primed PMN may play a major role in the pathogenesis of ARDS-associated lung injury.

[Non-invasive methods in the study of the elastic properties of the thoracic aorta. Effect of isosorbide dinitrate]

The role of the great arteries is to distribute and stock blood. Pulsatile discontinuous flow is transformed to a continuous flow system. The elastic properties of the aorta play a major role in these functions. It is generally agreed that changes in these elastic properties may lead to the development of left ventricular hypertrophy. The evaluation of the aorta has, until recently, depended on invasive hemodynamic and angiographic techniques. In addition, the measurement of pulse wave velocity, though useful, is a global and only an approximate method. Transoesophageal echocardiography (TEE) enables accurate measurement of the aortic diameter and its systolo-diastolic variations. The accuracy of these measurements has been validated in vitro and the reproducibility is much better than with previously used techniques. Previous studies have shown an improvement of the elastic properties of the great arteries with nitrate derivatives. In recent studies using TEE, isosorbide dinitrate caused dilatation of the descending thoracic aorta and thereby improved its elastic properties. The development of tonometry techniques in our department has resulted in the finding of excellent correlations between carotid and aortic pulse pressures measured non-invasively. The association of TEE and tonometry thereby provides a direct approach to the evaluation of aortic compliance. It has then become possible to study the effects of nitrate derivatives on the aortic compliance of elderly patients in whom it is the most reduced.

Procedures for the diagnosis of pneumonia in ICU patients

The optimal technique for diagnosing nosocomial bacterial pneumonia in critically ill patients cared for in the intensive care unit remains unclear, especially in the subgroup of patients requiring mechanical ventilation. An important advance has been the development of the protected specimen brush technique. Secretions obtained using this technique and evaluated by quantitative cultures are useful in distinguishing patients with and without pneumonia. However, this procedure has important limitations in that results are not available immediately, and in that a few false negative of false positive results may occur. Bronchoalveolar lavage has been suggested to be of value in establishing the diagnosis of pneumonia, because the cells and liquid recovered can be examined microscopically immediately after the procedure and are also suitable for quantitative culture. Microscopic identification of bacteria within cells recovered by lavage may provide a sensitive and specific means for the early and rapid diagnosis of pneumonia in this setting. The lavage technique can also be conveniently incorporated into a protocol along with quantitative culture of samples obtained using the protected specimen brush. This combination will probably improve the overall accuracy of diagnosis while allowing the administration of prompt empiric antimicrobial therapy in most patients with pneumonia.

Characterization of distal bronchial microflora during acute exacerbation of chronic bronchitis. Use of the protected specimen brush technique in 54 mechanically ventilated patients

To obtain accurate information on distal bronchial microflora during acute exacerbation in patients with chronic bronchitis, we prospectively studied 54 such patients who had been receiving mechanical ventilation because of hypercapnic respiratory failure. Fiberoptic bronchoscopy using a protected specimen brush (PSB) was performed on each patient within the first 24 h after admission. Cultures of protected brush specimens demonstrated no growth in 27 patients (50%). With the exception of fever (38.2 +/- 0.8 versus 37.7 +/- 0.6 degrees C; p less than 0.05), the initial severity of the episode of exacerbation was similar in patients with and without infection. A total of 44 organisms were isolated in the 27 patients with positive cultures; the predominant pathogens were Hemophilus spp. and Streptococcus spp. (involved in 74% of cases), but other organisms were isolated in 12 of 27 patients. Mortality rates, duration of mechanical ventilation, and duration of hospitalization were not significantly different between patients with bronchial microflora treated with appropriate antimicrobial therapy (n = 27) and patients without bronchial microflora either receiving empirical antibiotic therapy (n = 18) or not (n = 9). These data suggest that distal bronchial infection due to the usual pathogens, as far as shown by protected specimen brush cultures, may not be the sole or even the predominant cause of acute exacerbation of chronic bronchitis in patients requiring mechanical ventilation.

Bronchoalveolar lavage for rapid diagnosis of the fat embolism syndrome in trauma patients

OBJECTIVE

To evaluate the usefulness of bronchoalveolar lavage in establishing the diagnosis of the fat embolism syndrome in trauma patients with long-bone fractures.

DESIGN

Case series.

SETTING

Referral hospital.

PATIENTS

Eighteen trauma patients with long-bone fractures, including 5 with definite fat embolism syndrome, 5 in whom the diagnosis had been clinically suspected but was impossible to confirm or exclude before bronchoscopy, and 8 with no clinical evidence of the syndrome. Control groups included 9 patients without previous trauma who developed the adult respiratory distress syndrome for various reasons and 15 normal volunteers.

MEASUREMENTS AND MAIN RESULTS

Each patient had fiber-optic bronchoscopy with bronchoalveolar lavage, and the percentage of lavage cells containing intracellular fat droplets stained with oil red 0 were determined. In the five patients with definite fat embolism syndrome, light microscopic study of bronchoalveolar cells stained with oil red 0 showed many large intracellular fat droplets (mean percentage of cells containing fat droplets, 63%; range, 31% to 82%), whereas less than 2% of cells recovered by lavage from trauma patients with no clinical evidence of the syndrome, from patients with the adult respiratory distress syndrome, or from normal volunteers contained such inclusions. Use of the same technique in the five patients with possible fat embolism syndrome permitted the immediate identification of three patients in whom this diagnosis was later confirmed by subsequent autopsy or clinical follow-up.

CONCLUSIONS

The identification of fat droplets within cells recovered by bronchoalveolar lavage in trauma patients may be a rapid and specific method for establishing the diagnosis of the fat embolism syndrome.

Fiberoptic bronchoscopy in ventilated patients. Evaluation of cardiopulmonary risk under midazolam sedation

One hundred seven acutely ill ventilated patients were prospectively studied to ascertain the severity and frequency of alterations in gas exchange and hemodynamic parameters during brief bronchoscopy. Sedation was performed using midazolam (0.1 mg/kg IV) without topical anesthesia. An average decline in PaO2 of 26 percent was observed at the end of the procedure, compared to the baseline value, and this was associated with a mild increase in PaCO2 in spite of the use of a special adapter. Alterations in mean systolic blood pressure appeared to be modest, consisting of a 10 percent decrease from the control level, related to sedation, and a 10 percent rise from baseline during the procedure, associated with a concomitant mild tachycardia. At that time, central hemodynamic measurements performed in a subset of 31 patients showed a significant increase in cardiac output associated with higher pulmonary wedge pressure. Fourteen patients developed hypoxemia of less than 60 mm Hg on FIO2 adjusted to 0.8. Of the ten risk factors univariately associated with hypoxemia, only the presence of ARDS (p less than 0.001) and "fighting" the ventilator during the procedure (p less than 0.05) remained significant after stepwise logistic regression. Attempts to prevent hypoxemia in critically ill patients should focus on inducing complete sedation, with careful attention to hemodynamic status, or providing maximal levels of oxygen to the ventilator (or both).