Alain Durocher

Risk of acquiring multidrug-resistant Gram-negative bacilli from prior room occupants in the intensive care unit

The objective of this prospective cohort study was to determine whether admission to an intensive care unit (ICU) room previously occupied by a patient with multidrug-resistant (MDR) Gram-negative bacilli (GNB) increases the risk of acquiring these bacteria by subsequent patients. All patients hospitalized for >48 h were eligible. Patients with MDR GNB at ICU admission were excluded. The MDR GNB were defined as MDR Pseudomonas aeruginosa, Acinetobacter baumannii and extended spectrum β-lactamase (ESBL) -producing GNB. All patients were hospitalized in single rooms. Cleaning of ICU rooms between two patients was performed using quaternary ammonium disinfectant. Risk factors for MDR P. aeruginosa, A. baumannii and ESBL-producing GNB were determined using univariate and multivariate analysis. Five hundred and eleven consecutive patients were included; ICU-acquired MDR P. aeruginosa was diagnosed in 82 (16%) patients, A. baumannii in 57 (11%) patients, and ESBL-producing GNB in 50 (9%) patients. Independent risk factors for ICU-acquired MDR P. aeruginosa were prior occupant with MDR P. aeruginosa (OR 2.3, 95% CI 1.2-4.3, p 0.012), surgery (OR 1.9, 95% CI 1.1-3.6, p 0.024), and prior piperacillin/tazobactam use (OR 1.2, 95% CI 1.1-1.3, p 0.040). Independent risk factors for ICU-acquired A. baumannii were prior occupant with A. baumannii (OR 4.2, 95% CI 2-8.8, p <0.001), and mechanical ventilation (OR 9.3, 95% CI 1.1-83, p 0.045). Independent risk factors for ICU-acquired ESBL-producing GNB were tracheostomy (OR 2.6, 95% CI 1.1-6.5, p 0.049), and sedation (OR 6.6, 95% CI 1.1-40, p 0.041). We conclude that admission to an ICU room previously occupied by a patient with MDR P. aeruginosa or A. baumannii is an independent risk factor for acquisition of these bacteria by subsequent room occupants. This relationship was not identified for ESBL-producing GNB.

Nosocomial tracheobronchitis in mechanically ventilated patients: incidence, aetiology and outcome

The aim of this study was to determine the incidence, the organisms responsible for and the impact on outcome of nosocomial tracheobronchitis (NTB) in the intensive care unit (ICU). This prospective observational cohort study was conducted in a 30-bed medical/surgical ICU over a period of 6.5 yrs. All patients ventilated for >48 h were eligible. Patients with nosocomial pneumonia (NP) without prior NTB were excluded. Patients with first episodes of NTB were compared with those without NTB by univariate analysis. The study diagnosed 201 (10.6%) cases of NTB. Pseudomonas aeruginosa was the most common bacteria. NP rates were similar in patients with NTB compared with patients without NTB. Even in the absence of subsequent NP, NTB was associated with a significantly higher length of ICU stay and duration of mechanical ventilation in both surgical and medical populations. Mortality rates were similar in NTB patients without subsequent NP compared with patients without NTB. Antimicrobial treatment in NTB patients was associated with a trend to a better outcome. Nosocomial tracheobronchitis is common in mechanically ventilated intensive care unit patients. In this population, nosocomial tracheobronchitis was associated with longer durations of intensive care unit stay and mechanical ventilation. Further studies are needed to determine the impact of antibiotics on outcomes of patients with nosocomial tracheobronchitis.

Effect of ventilator-associated tracheobronchitis on outcome in patients without chronic respiratory failure: a case-control study.

IntroductionOur objective was to determine the effect of ventilator-associated tracheobronchitis (VAT) on outcome in patients without chronic respiratory failure.MethodsThis was a retrospective observational matched study, conducted in a 30-bed intensive care unit (ICU). All immunocompetent, nontrauma, ventilated patients without chronic respiratory failure admitted over a 6.5-year period were included. Data were collected prospectively. Patients with nosocomial pneumonia, either before or after VAT, were excluded. Only first episodes of VAT occurring more than 48 hours after initiation of mechanical ventilation were studied. Six criteria were used to match cases with controls, including duration of mechanical ventilation before VAT. Cases were compared with controls using McNemars test and Wilcoxon signed-rank test for qualitative and quantitative variables, respectively. Variables associated with a duration of mechanical ventilation longer than median were identified using univariate and multivariate analyses.ResultsUsing the six criteria, it was possible to match 55 (87%) of the VAT patients (cases) with non-VAT patients (controls). Pseudomonas aeruginosa was the most frequently isolated bacteria (34%). Although mortality rates were similar between cases and controls (29% versus 36%; P = 0.29), the median duration of mechanical ventilation (17 days [range 3–95 days] versus 8 [3–61 days]; P < 0.001) and ICU stay (24 days [range 5–95 days] versus 12 [4–74] days; P < 0.001) were longer in cases than in controls. Renal failure (odds ratio [OR] = 4.9, 95% confidence interval [CI] = 1.6–14.6; P = 0.004), tracheostomy (OR = 4, 95% CI = 1.1–14.5; P = 0.032), and VAT (OR = 3.5, 95% CI = 1.5–8.3; P = 0.004) were independently associated with duration of mechanical ventilation longer than median.ConclusionVAT is associated with longer durations of mechanical ventilation and ICU stay in patients not suffering from chronic respiratory failure.

Relationship between tracheotomy and ventilator-associated pneumonia: a case–control study

The aim of the present study was to determine the relationship between tracheotomy and ventilator-associated pneumonia (VAP). The study used a retrospective case–control study design based on prospective data. All nontrauma immunocompetent patients, intubated and ventilated for >7 days, were eligible for inclusion in the study. A diagnosis of VAP was based on clinical, radiographical and microbiological criteria. Four matching criteria were used, including duration of mechanical ventilation (MV). The indication and timing of tracheotomy were at the discretion of attending physicians. Univariate and multivariate analyses were performed to determine risk factors for VAP in cases (patients with tracheotomy) and controls (patients without tracheotomy). In total, 1,402 patients were eligible for inclusion. Surgical tracheotomy was performed in 226 (16%) patients and matching was successful for 177 (78%). The rate of VAP (22 versus 14 VAP episodes·1,000 MV-days−1) was significantly higher in controls than in cases. The rate of VAP after tracheotomy in cases, or after the corresponding day of MV in controls, was also significantly higher in control than in case patients (9.2 versus 4.8 VAP episodes·1,000 MV-days−1). In multivariate analysis, neurological failure (odds ratio (95% confidence interval) 2.7 (1.3–5)), antibiotic treatment (2.1 (1.1–3.2)) and tracheotomy (0.18 (0.1–0.3)) were associated with VAP. In summary, the present study demonstrates that tracheotomy is independently associated with decreased risk for ventilator-associated pneumonia.

Accuracy of American Thoracic Society/Infectious Diseases Society of America criteria in predicting infection or colonization with multidrug-resistant bacteria at intensive-care unit admission

The aim of this prospective observational study was to determine the accuracy of American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) criteria in predicting infection or colonization related to multidrug-resistant (MDR) bacteria at intensive-care unit (ICU) admission. MDR bacteria were defined as methicillin-resistant Staphylococcus aureus, ceftazidime-resistant or imipenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and extended-spectrum β-lactamase-producing Gram-negative bacilli. Screening for MDR bacteria (using nasal and rectal swabs and tracheal aspirates from intubated patients) was performed at ICU admission. Risk factors for infection or colonization with MDR bacteria at ICU admission were determined using univariate and multivariate analyses. The accuracy of ATS/IDSA criteria in predicting infection or colonization with these bacteria at ICU admission was calculated. Eighty-three (13%) of 625 patients were infected or colonized with MDR bacteria at ICU admission. Multivariate analysis allowed identification of prior antimicrobial treatment (OR 2.3, 95% CI 1.2-4.3; p 0.008), residence in a nursing home (OR 2, 95% CI 1.1-3.7; p <0.001), and prior hospitalization (OR 3.9, 95% CI 1.7-8.8; p <0.001) as independent predictors of infection or colonization with MDR bacteria at ICU admission. Although sensitivity (89%) and negative predictive values (96%) were high, low specificity (39%) and a positive predictive value (18%) were found when ATS/IDSA criteria were used in predicting infection or colonization with MDR bacteria at ICU admission. In patients with pneumonia, adherence to guidelines was associated with increased rates of appropriate initial antibiotic treatment and de-escalation. ATS/IDSA criteria had an excellent negative predictive value and a low positive predictive value concerning infection or colonization with MDR bacteria at ICU admission.

Intensive care unit-acquired infection as a side effect of sedation

IntroductionSedative and analgesic medications are routinely used in mechanically ventilated patients. The aim of this review is to discus epidemiologic data that suggest a relationship between infection and sedation, to review available data for the potential causes and pathophysiology of this relationship, and to identify potential preventive measures.MethodsData for this review were identified through searches of PubMed, and from bibliographies of relevant articles.ResultsSeveral epidemiologic studies suggested a link between sedation and ICU-acquired infection. Prolongation of exposure to risk factors for infection, microaspiration, gastrointestinal motility disturbances, microcirculatory effects are main mechanisms by which sedation may favour infection in critically ill patients. Furthermore, experimental evidence coming from studies both in humans and animals suggest that sedatives and analgesics present immunomodulatory properties that might alter the immunologic response to exogenous stimuli. Clinical studies comparing different sedative agents do not provide evidence to recommend the use of a particular agent to reduce ICU-acquired infection rate. However, sedation strategies aiming to reduce the duration of mechanical ventilation, such as daily interruption of sedatives or nursing-implementing sedation protocol, should be promoted. In addition, the use of short acting opioids, propofol, and dexmedetomidine is associated with shorter duration of mechanical ventilation and ICU stay, and might be helpful in reducing ICU-acquired infection rates.ConclusionsProlongation of exposure to risk factors for infection, microaspiration, gastrointestinal motility disturbances, microcirculatory effects, and immunomodulatory effects are main mechanisms by which sedation may favour infection in critically ill patients. Future studies should compare the effect of different sedative agents, and the impact of progressive opioid discontinuation compared with abrupt discontinuation on ICU-acquired infection rates.

Outcomes of ventilated COPD patients with nosocomial tracheobronchitis: a case-control study.

Abstract.Background:The aim of this study was to determine the impact of nosocomial tracheobronchitis (NTB) related to new bacteria on the outcome in patients with chronic obstructive pulmonary disease (COPD).Patients and Methods:A prospective observational case-control study was conducted in medical COPD patients requiring intubation and mechanical ventilation for more than 48 hours. Patients with nosocomial pneumonia were excluded. Six matching criteria were used, including the duration of mechanical ventilation before NTB occurrence.Results:81 matched case-control pairs were studied. Although the mortality rate was similar (40% vs 34%; p = 0.48), median duration of mechanical ventilation (20 vs 12 days; p = 0.015) and intensive care unit (ICU) stay (25 vs 18 days; p = 0.022) were higher in cases than in controls. NTB was independently associated with a longer than median period of mechanical ventilation among case and control patients (OR = 4.7 [95%CI = 2–10.9]; p < 0.001). In cases with appropriate antibiotic treatment compared with those who did not receive antibiotics, a shorter median duration of mechanical ventilation (12 vs 23 days; p = 0.006) and ICU stay (16 vs 29 days; p = 0.029) were observed.Conclusion:NTB is associated with an increased duration of mechanical ventilation and ICU stays. Further studies are required to determine whether antibiotics could improve the outcome of patients with NTB.

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

OBJECTIVE To determine the impact of COPD on intensive care unit (ICU) mortality in patients with VAP. METHODS This prospective observational study was performed in a mixed ICU during a 3-year period. Eligible patients received mechanical ventilation for >48 h and met criteria for microbiologically confirmed VAP. Risk factors for ICU mortality were determined using univariate and multivariable analyses. RESULTS Two hundred and fifteen patients with microbiologically confirmed VAP were included. Most VAP episodes were late-onset (88%), and Pseudomonas aeruginosa was the most frequently isolated bacterium (39% of VAP episodes). ICU mortality was significantly lower in non-COPD patients (n = 150) compared to COPD patients (n = 65) (43.3% vs 60%, p = 0.027, OR [95% CI] = 1.96 [1.8-3.54]). Duration (days) of mechanical ventilation and ICU stay median (IQR) in non-COPD patients were 25 (15-42) and 30 (18-48), whereas in COPD patients were 31 (19-45) and 36 (20-48) (p > 0.05). The differences in duration (days) of mechanical ventilation and ICU stay were significant between non-COPD patients and severe COPD (GOLD stage IV) patients (p = 0.001 and p = 0.02, respectively). Multivariable analysis identified COPD [OR (95% CI) 2.58 (1.337-5)], SAPS II [1.024 (1.006-1.024)] and presence of shock at VAP diagnosis [3.72 (1.88-7.39)] as independent risk factors for ICU mortality. CONCLUSION COPD, SAPS II, and shock at VAP diagnosis are independently associated with ICU mortality in patients who present VAP.

Factors Predicting Bacterial Involvement in Severe Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background: Strategies aiming at reducing antibiotic use are required in the intensive care unit (ICU). Although antibiotic treatment is recommended in patients with severe exacerbation of chronic obstructive pulmonary disease (COPD), a bacterial etiology is found in only a half of these patients. Objectives: The aim of this study was to determine factors predicting bacterial isolation in severe acute exacerbations of COPD. Methods: All patients with severe acute exacerbation of COPD requiring intubation and mechanical ventilation were included in this prospective observational cohort study. At ICU admission, information on endotracheal aspirate purulence and hyperthermia was collected. In all patients, Gram stain and quantitative endotracheal aspirate culture (positive at 106 cfu/ml) were performed. In addition, leukocyte count, C-reactive protein and procalcitonin (PCT) levels were measured. Results: Ninety-eight severe acute exacerbations of COPD requiring intubation and mechanical ventilation were studied. Forty-nine bacteria were isolated at significant threshold in 40 exacerbations. Streptococcus pneumoniae (16%), methicillin-sensitive Staphylococcus aureus (16%) and Hemophilus influenzae (14%) were the most frequently isolated bacteria. PCT >0.5 ng/ml and positive Gram stain of endotracheal aspirate were independently associated with bacterial isolation in severe acute exacerbation of COPD. Positive Gram stain and PCT >0.5 ng/ml had a negative predictive value >95%. Similar results were found after excluding patients with prior antibiotic treatment. Conclusion: Positive Gram stain of endotracheal aspirate and PCT >0.5 ng/ml are independently associated with bacterial isolation in severe acute exacerbation of COPD. These results could be helpful for future interventional studies aiming at reducing antibiotic use in these patients.

Risk factors for relapse of ventilator-associated pneumonia related to nonfermenting Gram negative bacilli: A case–control study

BACKGROUND The aim of this study was to determine risk factors for relapse of ventilator-associated pneumonia (VAP) related to nonfermenting Gram negative bacilli (NF-GNB). METHODS This is a retrospective case-control study based on prospectively collected data. Two hundred and seventy six patients with monobacterial VAP related to NF-GNB were eligible. Patients with subsequent superinfection or persistent pulmonary infection were excluded. Patients with relapse of NF-GNB VAP were matched (1:2) with patients without relapse. Matching criteria included the duration of mechanical ventilation before VAP relapse, age+/-5 years, SAPS II at ICU admission+/-5, and the date of admission. Univariate and multivariate analyses were used to determine risk factors for relapse of NF-GNB VAP in cases and controls. RESULTS Thirty (10%) patients developed a relapse of NF-GNB VAP, 27 (90%) patients were successfully matched with 54 controls. Inappropriate initial antibiotic treatment was the only variable independently associated with relapse of VAP related to NF-GNB (OR [95% CI]=8.1 [2-33], p=0.003). Although ICU-mortality rate was similar in cases and controls (55% vs 72%, p=0.132), the duration of mechanical ventilation and ICU stay were significantly higher in cases than in controls. CONCLUSION Inappropriate initial antibiotic treatment is independently associated with relapse of VAP related to NF-GNB.