Daniel Mathieu

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.

Protected Specimen Brush in the Assessment of Ventilator-Associated Pneumonia: Selection of a Certain Lung Segment for Bronchoscopic Sampling Is Unnecessary

The protected specimen brush (PSB) with quantitative cultures is one of the most reliable techniques for assessing pneumonia in mechanically ventilated (MV) patients. The need to select a certain lung segment for bronchoscopic sampling is still debated. We investigated whether the results of PSB specimens collected within an area radiographically involved with pneumonia (inv-PSB) differed from the results of PSB specimens collected within a lung area without radiographic abnormalities (non-inv-PSB) in 39 MV patients with suspected pneumonia. The comparison of bacterial titers of inv-PSB and non-inv-PSB cultures did not disclose significant differences. Agreement regarding the diagnosis of pneumonia according to recommended diagnostic threshold was observed in 34 of 39 patients (87.1 percent). These results which are in accordance with the pathophysiology of ventilator-associated pneumonia and histologic studies do not support the need to select a certain lung segment for bronchoscopic sampling in most MV patients with suspected pneumonia.

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.

Clinical Investigations in Critical CareProtected Specimen Brush in the Assessment of Ventilator-Associated Pneumonia: Selection of a Certain Lung Segment for Bronchoscopic Sampling Is Unnecessary

The protected specimen brush (PSB) with quantitative cultures is one of the most reliable techniques for assessing pneumonia in mechanically ventilated (MV) patients. The need to select a certain lung segment for bronchoscopic sampling is still debated. We investigated whether the results of PSB specimens collected within an area radiographically involved with pneumonia (inv-PSB) differed from the results of PSB specimens collected within a lung area without radiographic abnormalities (non-inv-PSB) in 39 MV patients with suspected pneumonia. The comparison of bacterial titers of inv-PSB and non-inv-PSB cultures did not disclose significant differences. Agreement regarding the diagnosis of pneumonia according to recommended diagnostic threshold was observed in 34 of 39 patients (87.1 percent). These results which are in accordance with the pathophysiology of ventilator-associated pneumonia and histologic studies do not support the need to select a certain lung segment for bronchoscopic sampling in most MV patients with suspected pneumonia.

Remifentanil discontinuation and subsequent intensive care unit-acquired infection: a cohort study

IntroductionRecent animal studies demonstrated immunosuppressive effects of opioid withdrawal resulting in a higher risk of infection. The aim of this study was to determine the impact of remifentanil discontinuation on intensive care unit (ICU)-acquired infection.MethodsThis was a prospective observational cohort study performed in a 30-bed medical and surgical university ICU, during a one-year period. All patients hospitalised in the ICU for more than 48 hours were eligible. Sedation was based on a written protocol including remifentanil with or without midazolam. Ramsay score was used to evaluate consciousness. The bedside nurse adjusted sedative infusion to obtain the target Ramsay score. Univariate and multivariate analyses were performed to determine risk factors for ICU-acquired infection.ResultsFive hundred and eighty-seven consecutive patients were included in the study. A microbiologically confirmed ICU-acquired infection was diagnosed in 233 (39%) patients. Incidence rate of ICU-acquired infection was 38 per 1000 ICU-days. Ventilator-associated pneumonia was the most frequently diagnosed ICU-acquired infection (23% of study patients). Pseudomonas aeruginosa was the most frequently isolated microorganism (30%). Multivariate analysis identified remifentanil discontinuation (odds ratio (OR) = 2.53, 95% confidence interval (CI) = 1.28 to 4.99, P = 0.007), simplified acute physiology score II at ICU admission (1.01 per point, 95% CI = 1 to 1.03, P = 0.011), mechanical ventilation (4.49, 95% CI = 1.52 to 13.2, P = 0.006), tracheostomy (2.25, 95% CI = 1.13 to 4.48, P = 0.021), central venous catheter (2.9, 95% CI = 1.08 to 7.74, P = 0.033) and length of hospital stay (1.05 per day, 95% CI = 1.03 to 1.08, P < 0.001) as independent risk factors for ICU-acquired infection.ConclusionsRemifentanil discontinuation is independently associated with ICU-acquired infection.

Unintentional strangulation by a cervical collar after attempted suicide by hanging

We report the case of a young man who attempted suicide by hanging and whose neurological status deteriorated until the cervical collar, that had been correctly placed by the prehospital team, was removed. We discuss the physiopathological mechanisms leading to death in hanging that is, a blockage of the blood stream to the brain leading to vasogenic and cytotoxic cerebral edema rather than asphyxia or spinal fracture. Our case supports the early removal of neck stabilization devices that can dangerously harm the patient after an attempted suicide by hanging, by increasing intracerebral pressure.

Manual compression of the abdomen to assess expiratory flow limitation during mechanical ventilation.

PURPOSE The aim of this study was to evaluate the manual compression of the abdomen (MCA) during expiration as a simple bedside method to detect expiratory flow limitation (EFL) during daily clinical practice of mechanical ventilation (MV). METHODS We studied 44 semirecumbent intubated and sedated critically ill patients. Flow-volume loops obtained during MCA were superimposed upon the preceding breaths and recorded with the ventilator. Expiratory flow limitation was expressed as percentage of expiratory tidal volume without any increase in flow during MCA (MCA [%V(T)]). In the first 13 patients, MCA was validated by comparison with the negative expiratory pressure (NEP) technique. Esophageal pressure changes during MCA and intrinsic positive end-expiratory pressure were also recorded in all the patients. RESULTS Manual compression of the abdomen and NEP agreed in all cases in detecting EFL with a bias of -0.16%. Percentage of expiratory tidal volume without any increase in flow during MCA is highly correlated with percentage of expiratory tidal volume without any increase in flow during NEP (n = 13, P < .0001, r(2) = 0.99) and intrinsic positive end-expiratory pressure (n = 44, P < .001, r(2) = 0.78), with a good repeatability (n = 44; within-subject SD, 5.7%) and reproducibility (n = 13; within-subject SD, 2.41%). Two third of the patients were flow limited, among whom one third had no previously known respiratory disease. CONCLUSIONS Manual compression of the abdomen provides a simple, rapid, and safe bedside reliable maneuver to detect and quantify EFL during mechanical ventilation.

Postoperative Ischemic Bronchitis After Lymph Node Dissection and Primary Lung Cancer Resection

BACKGROUND The purpose of this study was to determine the incidence and symptoms of postoperative ischemic bronchitis (POIB) after systematic lymph node dissection (LND) and evaluate the effect of hyperbaric oxygen therapy in patients with primary lung cancer. METHODS From January 2004 to December 2009, 1,071 patients underwent a standard resection for non-small cell lung cancer and radical systematic lymph node dissection. Fiberoptic bronchoscopy was performed systematically between days 7 and 12. We analyzed the clinical and biologic signs of POIB. Once the diagnosis established a treatment by hyperbaric oxygen, therapy was undertaken. RESULTS A POIB was observed in 34 patients (3.21%) (2 women and 32 men). Mean age was 59 ± 10 years (range, 25 to 79 years). A POIB occurred within 8 ± 3 days; after right pulmonary resection (n = 21; 62%) and after left resection (n = 13; 38%). A POIB appeared asymptomatically for 27 patients (80%), whereas only 7 patients (20%) presented with fever and hyperleukocytosis. Their localization were bronchial stumps (n = 21; 62%), homolateral bronchial tree (n = 11; 32%), or extension toward the contralateral bronchial tree (n = 2; 6%). The mean number of hyperbaric oxygen therapy sessions was 14 (1 to 48). A POIB worsening was observed in 6 patients (18%), requiring a surgical rescue therapy. CONCLUSIONS The clinical presentation of POIB is poor and systematic fiberoptic bronchoscopy should be performed, especially in patients with a high risk of bronchopleural fistula. Hyperbaric oxygen therapy in the management of ischemic bronchitis may be a promising adjunctive treatment.

Endocan (endothelial cell-specific molecule-1) as a pertinent biomarker of endothelial dysfunction in sepsis

One of the main players in the severity of sepsis is the endothelium integrity. Endocan, also called endothelial cell-specific molecule-1 (ESM-1), was shown to be preferentially expressed in lung vasculature. Structurally, endocan/ESM-1 is a 50 kDa proteoglycan that can interact with ICAM-1 and LFA-1 integrins and consequently prevents inflammatory events. In an experimental rat endotoxemic shock model, we previously showed that a decrease in the leukocyte-endothelial cell contacts (induced by drugs) is clearly linked to an increase of blood endocan levels. Blood levels of endocan/ESM-1 were also shown to be associated with the severity and evolution of septic states in preliminary studies.