Is a short trial of prone positioning sufficient to predict the improvement in oxygenation in patients with acute respiratory distress syndrome?

OBJECTIVE: To determine whether a 1-h trial of prone positioning is sufficient to identify responders. DESIGN: Prospective clinical cohort study in a medico-surgical ICU in a teaching hospital. PATIENTS: 49 patients with acute respiratory distress syndrome. INTERVENTIONS: A 6-h period of prone positioning. MEASUREMENTS AND RESULTS: Baseline measurements (blood gas analysis and respiratory parameters) were evaluated in supine position just prior to turning the patients prone. Measurements were then repeated 1 h after the beginning of prone positioning (PP1h) and at the end of the 6-h period of prone positioning (PP6h). The last measurements were performed 1 h after repositioning the patients supine. Prone position induced an increase in the PaO2/FIO2 ratio (p < 0.001). A response (increase in PaO2/FIO2 ratio of at least 20 % at PP1h and/or at PP6h) was observed in 37 of 49 patients (76%). Twenty-seven of these patients (73%) were responders at PP1h while 10 (27%) were responders only at PP6h- In all, two-thirds of the patients were considered persistent responders. However, whereas the PaO2/FIO2 ratio decreased significantly 1 h after repositioning the fast responders supine, the PaO2/ FIO2 ratio remained unchanged after repositioning slow responders. CONCLUSIONS: A short-term trial of prone positioning does not appear a sufficient method to identify patients who would benefit from the postural treatment.

Is ventilator-associated pneumonia an independent risk factor for death?

BACKGROUND: Ventilator-associated pneumonia (VAP) has been implicitly accused of increasing mortality. However, it is not certain that pneumonia is responsible for death or whether fatal outcome is caused by other risk factors for death that exist before the onset of pneumonia. The aim of this study was to evaluate the attributable mortality caused by VAP by performing a matched-paired, case-control study between patients who died and patients who were discharged from the intensive care unit after more than 48 h of mechanical ventilation. METHODS: During the study period, 135 consecutive deaths were included in the case group. Case-control matching criteria were as follows: (1) diagnosis on admission that corresponded to 1 of 11 predefined diagnostic groups; (2) age difference within 10 yr; (3) sex; (4) admission within 1 yr; (5) APACHE II score within 7 points; (6) ventilation of control patients for at least as long as the cases. Precise clinical, radiologic, and microbiologic definitions were used to identify VAP. RESULTS: Analysis was performed on 108 pairs that were matched with 91% of success. There were 39 patients (36.1%) who developed VAP in each group. Multivariate analysis showed that renal failure, bone marrow failure, and treatment with corticosteroids but not VAP were independent risk factors for death. There was no difference observed between cases and controls concerning the clinical and microbiologic diagnostic criteria for pneumonia. CONCLUSION: Ventilator-associated pneumonia does not appear to be an independent risk factor for death.

Long-term arterial cannulation in ICU patients using the radial artery or dorsalis pedis artery.

STUDY OBJECTIVES: To evaluate the rate of arterial thrombosis and catheter-related infection following radial artery or dorsalis pedis artery (DPA) cannulations lasting > or = 4 days. DESIGN: Prospective, observational study of two cohorts of ICU patients. SETTING: ICU of a university hospital. PATIENTS: In a first group of 131 consecutive patients, the DPA was selected for arterial cannulation. In the second group, 134 consecutive patients were considered for radial artery cannulation. MEASUREMENTS AND RESULTS: In the DPA group, the overall success rate for catheter placement was 85%. Patients were cannulated for 16 +/- 5 days (mean +/- SD). In the radial artery group, the overall success rate was 97.7% (129 of 132 patients; p < 0.0001 vs DPA group). Patients were cannulated for 13.3 +/- 4.0 days. In both groups, no signs of ischemia were detected at the clinical examination. In the DPA group, no thrombosis was detected at the angiographic examination in 21 patients (38%), a thrombosis without vessel obstruction was observed in 21 patients (31%), and a thrombosis with vessel obstruction was observed in 21 patients (31%). In the radial artery group, no thrombosis was observed in 31 patients (24%; not significant vs DPA group), a partial thrombosis was found in 73 patients (57%), and a total thrombosis with vessel obstruction was found in 25 patients (19%). Two cases of catheter-related infection were observed in the DPA group. In the radial artery group, four cases of catheter-related infection were diagnosed vs DPA group (not significant). CONCLUSIONS: The rate of serious complications was similar for both sites of arterial cannulation. Accepting a 12.7% lower rate of successful placement, the DPA route provides a safe and easily available alternative when radial arteries are not accessible.

High or low doses of almitrine bismesylate in ARDS patients responding to inhaled NO and receiving norepinephrine?

OBJECTIVE: To evaluate the effects on oxygenation and pulmonary haemodynamics of almitrine bismesylate (AB) 5 microg/kg per minute and 16 microg/kg per minute in ARDS patients responding to and receiving inhaled NO (iNO) and presenting septic shock requiring norepinephrine, while no difference was observed in a previous trial including iNO responders and nonresponders. DESIGN: Prospective, cohort study. SETTING: Adult medico-surgical intensive care unit of a university hospital. PATIENTS: Fifteen patients with ARDS receiving and responding to iNO (10 ppm) and presenting septic shock requiring norepinephrine (mean 0.5+/-0.45 microg/kg per minute, range 0.08- 2.08). INTERVENTIONS: The protocol consisted of two consecutive phases in a fixed order: continuous intravenous infusion of AB 5 microg/kg per minute for 30 min, and continuous intravenous infusion of AB 16 microg/kg per minute for 30 min. MEASUREMENTS AND MAIN RESULTS: AB 5 microg/kg per minute significantly increased PaO2/FiO2 ( P<0.05) compared with iNO alone [160 (range 77-450) mmHg vs 122 (range 70-225) mmHg]. AB 16 microg/kg per minute produced a greater increase of PaO2/FiO2 ( P<0.05) when compared with 5 microg/kg per minute [227 (range 84-501) mmHg]. AB did not improve shunt at any dose regimen. AB produced an increase in mean pulmonary arterial pressure (MPAP) from 22+/-5 to 25+/-4 mmHg ( P<0.03). MPAP did not significantly increase between the two doses. Pulmonary vascular resistances and other haemodynamic and respiratory parameters were not affected by almitrine bismesylate. CONCLUSIONS: These results suggest that it is possible to obtain a further improvement in oxygenation by increasing AB infusion rate in ARDS patients iNO responders receiving norepinephrine. Due to the potential deleterious effects of AB, this strategy should be used in the most severely hypoxaemic patients.

Diagnostic accuracy of protected catheter sampling in ventilator-associated bacterial pneumonia.

The aim of this study was to assess the accuracy of protected telescoping catheter performed using: 1) protected distal aspiration, or 2) protected mini-bronchoalveolar lavage for the diagnosis of ventilator-associated bacterial pneumonia. Twenty-seven patients who died after receiving mechanical ventilation for at least 72 h were included in a comparative prospective post-mortem study. The two microbiological sampling procedures were performed immediately after death. Surgical pneumonectomies and biopsies were performed within 30 min of death at the bedside for histological examination. The results of the two techniques were compared with histological post-mortem lung examination or biopsies. Histological examination of the parenchyma showed signs of pneumonia in 14 cases. Lung tissue culture was positive in nine of these 14 cases. When ventilator-associated bacterial pneumonia was defined by the association of histological signs and positive lung tissue culture the sensitivity was 78% for both sampling techniques, specificity was 86% for mini-bronchoalveolar lavage and 100% for protected distal aspiration (at a threshold of 1 x 10(3) cfu x mL(-1)). Both techniques protected the distal aspiration and mini-bronchoalveolar lavage, and provided good specificity with an acceptable sensitivity for the diagnosis of ventilator-associated bacterial pneumonia.

Inhaled nitric oxide and vasoconstrictors in acute respiratory distress syndrome.

It has been suggested that the increase in PO(2) observed with nitric oxide (NO) should be enhanced by the addition of a vasoconstrictor agent. The vasoconstrictor used in combination with NO should mimic or enhance hypoxic vasoconstriction. The aim of this study was to evaluate the respiratory and hemodynamic effects of norepinephrine (a nonspecific vasoconstrictor), almitrine bismesylate (a specific pulmonary vasoconstrictor), and inhaled NO, alone or together. During a 6-mo period, 16 patients presenting with ARDS were prospectively investigated. On inclusion, no patient was receiving cardiovasoactive drugs. The protocol consisted of seven consecutive phases: baseline, norepinephrine (in order to obtain a 3 mm Hg rise in mean pulmonary arterial pressure [Ppa]), almitrine bismesylate (16 micrograms/kg/min), inhaled NO (20 ppm delivered during inspiration), norepinephrine + inhaled NO, almitrine bismesylate + inhaled NO, almitrine bismesylate + norepinephrine + inhaled NO. General factorial analysis of variance showed that inhaled NO and almitrine bismesylate increased oxygenation (p < 0.0001). Norepinephrine had no effect on oxygenation. A synergistic effect between inhaled NO and almitrine bismesylate was found (p < 0.05), whereas norepinephrine did not affect the response to inhaled NO. Nitric oxide produced a significant decrease in Ppa and pulmonary vascular resistances (PVRI) (p < 0.0001). Both almitrine bismesylate and norepinephrine induced an increase in Ppa (p < 0.0001). Norepinephrine increased PVRI (p < 0.002), whereas almitrine bismesylate had no effect on PVRI. The present results support the hypothesis that a selective pulmonary vasoconstrictor enhances the increase in oxygenation induced by inhaled NO, whereas norepinephrine attenuates this effect.

Upper-extremity deep vein thrombosis after central venous catheterization via the axillary vein.

OBJECTIVE: To determine the frequency of central venous catheter-induced thrombosis of the axillary vein. DESIGN: Prospective, controlled study. SETTING: Tertiary care university center. PATIENTS: Sixty patients in a medical-surgical intensive care unit who required central venous catheterization via the axillary vein. INTERVENTIONS: Single-lumen, silicone elastomer or polyurethane catheters were inserted for a mean duration of 14.7+/-7.4 days (range, 4-33 days). On catheter removal, bilateral upper-extremity phlebographic examination was performed in each patient. The incidence of deep vein thrombosis in catheterized arms was compared with that in uncatheterized arms. MEASUREMENTS AND MAIN RESULTS: Of the 60 patients who underwent axillary vein cannulation, one patient had clinical signs of arm vein thrombosis, but no patient had clinical sign of pulmonary embolism. There were 35 patients (58.3%) who developed positive phlebographic examinations homolateral to the catheter. Fibrin sleeves that developed around the catheters were observed in 28 patients (47%). Five patients (8.3%) had phlebographic signs of partial axillary vein thrombosis: nonobstructive clots adherent to the vessel wall and/or the catheter. Two patients (3.3%) had phlebographic signs of complete axillary vein thrombosis. No thrombosis was observed in patients with catheterizations lasting < or =6 days, two cases were observed for duration of 7-14 days, and five cases were observed for duration of > or =15 days (p < .01). In the seven patients with axillary vein thrombosis, the vessel was cannulated with fewer than three puncture attempts, and the mean duration for catheter insertion (10+/-2.5 min) was not different from that of patients with no axillary vein thrombosis (14+/-9 min). CONCLUSIONS: Based on the data from the present study, we conclude that axillary vein catheterization is associated with a 11.6% frequency of upper-extremity deep vein thrombosis. This rate of vein thrombosis is similar to that observed after internal jugular or subclavian vein cannulation. Given the acceptable rate of this clinically important complication, axillary vein cannulation offers an attractive alternative site for catheter insertion to the internal jugular or subclavian vein in the critically ill. Because thrombosis is rare or absent in catheterizations lasting <15 days, it seems wise to withdraw axillary catheters after a maximum of 2 wks.

Inhaled NO and almitrine bismesylate in patients with acute respiratory distress syndrome: effect of noradrenalin.

The combination of inhaled nitric oxide with almitrine bismesylate has been proposed for the management of acute respiratory distress syndrome in order to divert pulmonary blood flow away from poorly ventilated toward well-ventilated areas. The aims of this prospective and comparative study were to: 1) confirm the beneficial effects on oxygenation of this association; 2) evaluate the haemodynamic effects of this association; and 3) evaluate the influence of noradrenaline (a nonspecific vasoconstrictor) on the modification of gas exchange related to inhaled NO and/or almitrine bismesylate. Forty-one sedated paralysed and ventilated patients were investigated. Haemodynamic and blood gas measurements were performed in a fixed order: baseline; inhalation of NO for 30 min.; intravenous infusion of almitrine bismesylate; and concomitant administration of inhaled NO and almitrine bismesylate. Inhaled NO and almitrine bismesylate increased arterial oxygen tension (Pa,O2)/inspiratory oxygen fraction (FI,O2) (p<0.001). The association of inhaled NO with almitrine bismesylate resulted in a dramatic improvement in Pa,O2/FI,O2 (p<0.0001 versus almitrine bismesylate, p<0.05 versus inhaled NO). In patients receiving noradrenalin (n = 19), almitrine bismesylate had no effect on oxygenation. The present study confirmed that the combination of inhaled NO with almitrine bismesylate improved oxygenation, and demonstrated that almitrine bismesylate has no effect on oxygenation in patients receiving noradrenalin.

Does norepinephrine modify the effects of inhaled nitric oxide in septic patients with acute respiratory distress syndrome?

UNLABELLED: Hypoxia-related pulmonary vasoconstriction enhanced by norepinephrine could be deleterious in patients with the acute respiratory distress syndrome (ARDS) and sepsis. A prospective study compared the effects of nitric oxide on cardiorespiratory parameters, including the evaluation of right ventricular function in patients with ARDS and sepsis who were receiving or not receiving norepinephrine. METHODS: During a 15-month period, 27 patients with ARDS and sepsis were prospectively investigated (group 1: 15 patients not receiving norepinephrine; group 2: 12 patients receiving norepinephrine). Right ventricular ejection fraction was measured by thermodilution. After baseline measurements, nitric oxide was administered at increasing inspiratory concentrations. RESULTS: The ratio of oxygen tension in arterial blood to the fractional concentration of oxygen in inspired gas increased in the two groups. After logarithmic transformation of the data, an analysis of variance was performed that did not show any difference between the two groups. A dose-dependent decrease in mean pulmonary arterial pressure was observed in the two groups. This decrease and the increase in right ventricular ejection fraction induced by inhaled nitric oxide were more marked when patients received norepinephrine (P < 0.0001). CONCLUSION: Norepinephrine did not influence the beneficial effects of inhaled nitric oxide administered to patients with ARDS and sepsis on oxygenation.

Open-lung biopsy in patients with acute respiratory distress syndrome.

BACKGROUND: It has been suggested that fibrosis present during the fibroproliferative phase of acute respiratory distress syndrome (ARDS) can be treated by corticosteroids. However, neither clinical nor microbiologic criteria permit differentiation of this fibroproliferative phase from a nosocomial pneumonia. The aim of this observational case series was to evaluate the safety and utility of open-lung biopsy (OLB) performed in patients receiving ventilatory support who had persistent ARDS despite negative bacterial cultures. METHODS: During a 4-yr period, 37 OLBs were performed in 36 of 197 patients receiving ventilatory support who had ARDS. The severity of ARDS was assessed by a lung injury score of 3.1 +/- 0.4 (mean +/- SD) and a median ratio of the partial pressure of oxygen (PaO2) to the fraction of inspired oxygen (FiO2) of 118 mmHg. Histologic examination; bacterial, fungal, and acid-fast staining; and cultures of the tissue sample were performed. RESULTS: Fibrosis was present in only 41% of the lung specimens obtained by OLB. Only six patients received corticosteroids (17%). In 9 of the 15 patients with fibrosis, cytomegalovirus pneumonia precluded the use of corticosteroids. Histologic cytomegalovirus pneumonia was diagnosed in 18 cases. Histologic bacterial or mycobacterial pneumonia was diagnosed in five cases. No significant change in arterial blood gases was noted as linked to the biopsy procedure except an increase of the PaO2/FiO2 ratio. One pneumothorax was diagnosed on a chest roentgenogram 12 h after OLB. Only one patient required blood transfusion during the 48-h period after OLB (for an hemothorax). Five patients had moderate air leaks from operative chest tubes for 2-10 days. CONCLUSIONS: Open lung biopsy appeared to be a useful and acceptably safe diagnostic technique in patients with ARDS. It permitted the diagnosis of unexpected cytomegalovirus pneumonia.

Catheter-related infections following axillary vein catheterization.

BACKGROUND: The aim of this study was to determine the rate of infectious complications following axillary vein cannulation and to compare to that observed after internal jugular vein catheterization. METHODS: A prospective comparative open study was carried out to determine the rate of infectious complications related to the use of catheters inserted via the axillary vein or the internal jugular vein. During the study period all patients submitted to central venous catheterization were evaluated. A total of 141 patients entered and completed the study. Catheter insertion sites were either the axillary vein punctured in the axilla, or the internal jugular vein punctured using an anterior approach. Catheter tips were cultured using a quantitative technique. Clinical information pertaining to the analysis was prospectively collected. RESULTS: A total of 141 catheters from 141 patients entered was studied. Clinical characteristics and risk factors for catheter infection were similar in both groups. The incidence of catheter-related infection (including catheter-related sepsis, and bacteremia) was not different between the two groups (axillary vein: 8.1%; internal jugular vein: 7.6%). Catheter-related bacteremia were seen at a rate of 3.7% in the internal jugular vein group and a rate of 1.6% in the axillary vein group (NS). The incidence of catheter colonization was similar in both groups (axillary vein: 14.5%; internal jugular vein: 11.4%). CONCLUSION: Catheter-related infection after axillary vein catheterization was similar to that observed after internal jugular vein catheterization. The chance of developing catheter-related sepsis was less than 10% with either route when catheters were used for the treatment of severely ill patients.

Respective and combined effects of prone position and inhaled nitric oxide in patients with acute respiratory distress syndrome.

Inhaled nitric oxide (NO) and prone position (PP) are two of the new therapeutics proposed in the setting of acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate the hemodynamic and respiratory effects of NO and prone position in patients with ARDS. Fourteen patients, sedated, paralyzed, and ventilated using volume-control mode, were prospectively investigated. All patients had a radial artery catheter, a pulmonary artery catheter, and a 3-F fiberoptic thermistor catheter advanced via the femoral artery into the descending aorta. The protocol consisted of seven phases: baseline measurements in supine position, SP (T0); SP + NO (T1); baseline 2 in SP (T2); PP without NO (T3); NO + PP (T4); SP + NO (T5); and PP + NO (T6). Inhaled NO (T1) induced an increase in PO2/FI(O2) (from 128 +/- 44 to 180 +/- 75 mm Hg, p < 0.004). Prone position (T3) resulted in an increase in PO2/FI(O2) (193 +/- 83 mm Hg, p < 0.003 versus T0). The association of NO with PP (T4) resulted in a significant improvement in PO2/FI(O2) (261 +/- 98 mm Hg) when compared with T0, T1, and T3. Analysis of variance showed a significant and additive effect of NO and PP on both PO2/FI(O2) (p < 0.000) and shunt fraction (QS/QT) (p < 0.01). Since the association of NO with PP presents additive effects on oxygenation, this association can be proposed for the treatment of ARDS.

Diagnosis of ventilator-associated pneumonia: an evaluation of direct examination and presence of intracellular organisms.

BACKGROUND: Ventilator-associated pneumonia (VAP) requires early diagnosis and adequate antibiotic therapy. The aim of this prospective postmortem study was to assess the accuracy of direct examination and quantification of intracellular organisms (ICO) for the diagnosis of VAP. METHODS: Total and differential cell counts were performed on fluids recovered using nonbronchoscopic sampling techniques (blind bronchial sampling [BBS], mini-bronchoalveolar lavage [mini-BAL]) and from bronchoalveolar lavage (BAL) performed during fiberscopy. These 3 sampling techniques were done within 15 min of death without discontinuing mechanical ventilation. Quantification of ICO was performed on each sample recovered from the various sampling procedures. Gram reaction and morphology of bacteria were evaluated on Gram smears. RESULTS: The results of each technique were compared with histology and culture of lung tissue specimens obtained by surgical pneumonectomies in 28 patients who died after at least 72 h of mechanical ventilation. Histology was positive in 13 patients and negative in 15 patients. When only VAP with positive lung culture was considered (histologic signs of bronchopneumonia plus positive lung tissue culture), the sensitivity of Gram staining on BAL, mini-BAL, and BBS was 56%, 44%, and 56%, respectively. If all samples were considered, the sensitivity and the specificity of the determination of the percentage of ICO were low (less than 70%) whatever the sampling technique. CONCLUSIONS: For initial therapeutic guidance, direct examination and presence of ICO do not contribute for establishing the diagnosis of VAP, essentially because of a lack of sensitivity. However, when positive, Gram staining can obviously guide initial antibiotherapy.

Early and fatal immune haemolysis after so-called 'minor' ABO-incompatible peripheral blood stem cell allotransplantation.

A 38-year-old man, blood group A+, was allotransplanted for multiple myeloma from his fully matched sister, blood group O+. Anti-A antibodies IgG and IgM titres of the donor were low. Allogeneic peripheral blood stem cells were harvested by leukapheresis after subcutaneous administration of G-CSF. Rapid engraftment occurred since 5.6 x 10(9)/l leukocytes were achieved on day +9 post-transplant. At this time a severe immune haemolytic syndrome occurred and direct antiglobulin test was positive (IgG and C3d). Elution showed an anti-A specificity. Evolution was rapidly unfavourable related to multiorgan failure. The patient died on day +20 post-transplant.

[Effects of intravenous immunoglobulins in thrombopenia related to septic shock]. / Effets des immunoglobulines intraveineuses sur les thrombopénies liées au choc septique.

OBJECTIVES: Intravenous immunoglobulins have been shown to be effective in the treatment of immunologically mediated thrombocytopenia. Several articles have been published on the positive effect of immunoglobulins in sepsis-related death. We retrospectively studied the effects of intravenous immunoglobulins used during septic shock thrombocytopenia over a 5-year period in a polyvalent intensive care unit. PATIENTS AND METHODS: Inclusion criteria were development of acute thrombocytopenia under 75 G/l during septic shock, excluding all cases of disseminated intravascular coagulation. Thirty-five patients were included in the study; 18 were given polyvalent intravenous immunoglobulins (group IgIV) and 17 were not (controls). The two groups were comparable for SAPS and APACHE II gravity scores at admission and at day 0 (first day of septic shock with platelet count under 75 G/l), age, sex, platelet count at admission, OSF score, type of referral unit, McCabe score, and the presence of 4 parameters which might affect platelet count hemofiltration, ARDS, surgery, Swan-Ganz catheter. RESULTS: Platelet counts increased on day 8 in the treatment group (63.5 G/l, range 25-453 versus 105.7 G/l, range 38-355; p = 0.0505). The number of days with thrombocytopenia was the same in both groups. Overall mortality was high (60%) but there was a difference between the two groups in favor of the treated group (74.7% versus 44.4%; p = 0.053). The number of red cell units (214 vs. 164) and plasma units (175 vs. 54) transfused was higher in the control group. Platelet transfusion was equivalent in the two groups. DISCUSSION: Although we were unable to demonstrate a significant difference in the effects of immunoglobulins on platelet level and mortality, the trend during this evaluation was comparable with that reported in the literature. For transfusion, and although the results were not significant, a notion of reduced risk was evident. Prospective trials are needed to confirm these observations.

Study of some phagocyte membrane receptors in patients receiving intravenous polyvalent immunoglobulins as adjunct treatment for nosocomial pneumonia.

PURPOSE: Phagocytosis is a major mechanism of defense against bacterial infections. The ingestion of bacteria by phagocytes involves a variety of cell membrane recognition structures and, among them, immunoglobulin receptors. The aim of this study was to test the phagocytic activity of granulocytes and monocytes of intensive care unit (ICU) patients, and to evaluate the effects of intravenous polyvalent immunoglobulins (IVIG) used as adjunct treatment of nosocomial pneumonia on some phagocyte membrane receptors of these patients. MATERIALS AND METHODS: The phagocytic activity of granulocytes and monocytes of 41 mechanically ventilated patients with nosocomial bacterial pneumonia was studied during the acute phase of infection. These ICU patients were compared with 21 hospitalized, noninfected volunteer patients hospitalized in a medical ward. Peripheral blood granulocytes and monocytes were studied. Of the 41 ICU patients, after randomization, 21 received IVIG at a dose of 1 g/kg for 3 days. The 41 ICU patients were compared with the 21 non-ICU, noninfected hospitalized controls. The 21 ICU patients who received 3 days of IVIG were also compared with the 20 ICU patients not receiving IVIG. Cells were tested in standard immunoglobulin-free medium (fetal calf serum) and in the presence of patients' serum. Blood granulocytes and monocytes were purified and separately exposed to three types of particles: antibody-coated erythrocytes (to test immunoglobulin receptors), opsonized zymosan (to test C3 receptors), and glutaraldehyde-treated erythrocytes (to test lectinlike or other nonspecific binding sites). Phagocytosis and superoxide anion production (oxidative burst) were measured. RESULTS: Granulocytes of ICU patients compared with those of non-ICU, noninfected patients exhibited a substantial decrease of zymosan ingestion (P < .05), whereas phagocytosis of other particles was normal. Monocytes from the ICU patients, compared with those of the non-ICU, noninfected patients, displayed an unselective overall decrease of phagocytic ability for the three particle types (P < .05). The phagocytosis activity of the three membrane receptor species of blood monocytes and granulocytes of ICU patients was not significantly modified by the IVIG infusion. For both monocytes and granulocytes, no significant improvement was observed in the fraction of cells that ingested at least one foreign particle and the mean number of particles per cell having phagocytized at least one foreign particle. Granulocyte and monocyte functions were also tested by the production of reduced ferricytochrome and no significant improvement in the oxidative burst was observed after infusion of IVIG. CONCLUSION: Infected ICU patients display a deficiency of phagocytosis membrane receptors of blood granulocytes and monocytes. The addition of IVIG to standard therapy does not improve the phagocytic activity of ICU patients with nosocomial pneumonia.

Effect of ventilator-associated pneumonia on mortality and morbidity.

The aim of this study was to evaluate the attributable mortality and excess intensive care unit (ICU) stay as linked to ventilator-associated pneumonia (VAP) in a medical-surgical ICU. We performed a matched cohort study. The diagnosis of VAP was established when clinical, biologic, and radiologic signs of VAP were associated with the presence of at least one microorganism at a concentration > or = 10(3) CFU/ml on the protected specimen brush sample. Each case patient with VAP was matched to one control patient on the basis of the following potential confounding factors: same diagnosis and same indication for mechanical ventilation, same age +/-5 yr, same sex, same APACHE II score +/-5 on admission. In addition, control patients had to be ventilated for at least as long as the case patient prior to the onset of VAP, and date of admission of the case and control patients had to be matched within 1 yr. In 85 of the 97 patients with VAP, we were able to match one case patient with one control patient. Mortality was similar in both case (40%) and control (38.8%) patients. The duration of mechanical ventilation was increased in survivor case patients (27.2 +/- 24.7 d) compared with survivor control patients (18.5 +/- 15.7 d) (p < 0.01). The duration of hospitalization in ICU was increased in survivor case patients (34.9 +/- 23.6 d) compared with survivor control patients (26.1 +/- 18.6 d) (p < 0.02). When confounding factors were controlled, VAP did not appear to increase mortality.

Molecular epidemiology of Enterobacter aerogenes acquisition: one-year prospective study in two intensive care units.

To evaluate the respective contributions of patient-to-patient transmission and endogenous acquisition of Enterobacter aerogenes isolates, we conducted a prospective epidemiologic study in two intensive care units (ICUs) between May 1994 and April 1995. We collected a total of 185 E. aerogenes isolates: 130 from 51 patients in a surgical ICU (SICU), 45 from 26 patients in a medical ICU (MICU), and 10 from the environments in these two ICUs. All isolates were typed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus PCR. Among the 175 clinical isolate, we observed 40 different profiles by random amplification of polymorphic DNA and 36 different profiles by enterobacterial repetitive intergenic consensus PCR. We identified a ubiquitous and prevalent clone, corresponding to 58% of SICU and 41% of MICU clinical isolates. Three epidemiologically related strains were specific to each ICU and represented 17% of SICU and 24% of MICU clinical isolates; unique type strains represented 17 and 29% of SICU and MICU clinical isolates, respectively, and E. aerogenes strains which were spread to a limited degree and which were isolated less than five times during the 1-year study period represented 8 and 6% of SICU and MICU clinical isolates, respectively. Our results show that E. aerogenes is acquired in the ICU in three different ways: patient-to-patient spread of a prevalent or an epidemiologically related strain, acquisition de novo of a strain from patients' own flora, and acquisition of a nonendemic strain followed by occasional patient-to-patient transmission. The findings point out the importance of patient-to-patient transmission in E. aerogenes acquisition and suggest that changes in E. aerogenes ecology in the hospital have taken place during the past decade.

Cytomegalovirus. An unexpected cause of ventilator-associated pneumonia.

BACKGROUND: Cytomegalovirus (CMV) frequently is observed in immunocompromised hosts. The aim of this study was to report cases of ventilator-associated CMV pneumonia diagnosed by pathologic examination in intensive care patients without acquired immunodeficiency syndrome or hematologic malignancy or who were not receiving immunosuppressive agents. METHODS: From June 1, 1989, to May 31, 1994, 2,785 patients were hospitalized. During the study period, 60 autopsies and 26 open-lung biopsies were performed in nonimmunocompromised patients who were seen with acute respiratory failure and/or symptoms suggestive of ventilator-associated pneumonia. Cytomegalovirus pneumonia was diagnosed using pulmonary samples by the identification of large cells with large nuclei containing a basophilic or eosinophilic inclusion surrounded by a light halo. These typical findings always were associated with a diffuse interstitial pneumonitis. RESULTS: Cytomegalovirus pneumonia was diagnosed after histologic examination in 25 patients. The reason for admission to the intensive care unit was major surgery in 13 patients and medical problems in 12 patients. Ventilator-associated CMV pneumonia was diagnosed by histologic examination 22.4 +/- 8.8 days after admission to the intensive care unit (median 18 days; range 10-40 days). The clinical description was similar with the 25 patients who were seen with ventilator associated CMV pneumonia and the 61 patients without ventilator-associated CMV pneumonia. However, there was a more severe hypoxemia 72 +/- 16 vs. 95 +/- 41 mmHg, P < 0.05) and a higher Weinberg's radiologic score (9.2 +/- 1.9 vs. 7.4. +/- 2.7, P < 0.05) in the ventilator-associated CMV pneumonia group. Diagnosis of ventilator-associated CMV pneumonia was made for 9 of 17 patients when shell-vial culture technique using fluorescein-labelled antibody E 13 was performed on bronchoalveolar lavage products. Four of the eight patients treated by ganciclovir therapy died of multiple organ dysfunction syndrome. CONCLUSIONS: The diagnosis of ventilator-associated CMV pneumonia should not be excluded in intensive care patients, even those without acquired immunodeficiency syndrome, hematologic malignancy, or immunosuppressive agents on admission.

Investigation of outbreaks of Enterobacter aerogenes colonisation and infection in intensive care units by random amplification of polymorphic DNA.

During a 4-month period, 41 isolates of Enterobactor aerogenes were cultured from different specimens from a 14-bed intensive care unit (ICU1). These were obtained from 12 patients out of a total of 187 patients admitted to the ICU. Sixteen E. aerogenes isolates were cultured from another ICU (ICU2) 6 months later. Six non-outbreaks associated strains were included as controls and all the isolates were compared by random amplification of polymorphic DNA (RAPD), with three different 10-mer oligonucleotide primers. RAPD fingerprinting with primer AP12h was as discriminatory as the combined results from all three primers and defined 22 different patterns for the 41 isolates from the ICU1. In nine instances, isolates with indistinguishable RAPD patterns were detected in two-to-five patients over a 3-15-day period, suggesting patient-to-patient transmission. During their stay in ICU1, patients harboured one-to-12 distinguishable isolates. Isolates from ICU2 were indistinguishable by RAPD analysis with the three different primers. These findings suggest that the cluster of colonisations and infections in ICU1 was a 'false outbreak', consisting of successive patient-to-patient transmission of different E. aerogenes strains. In contrast, the outbreak on ICU2 probably involved the extensive spread of a single strain.