Early-onset ventilator-associated pneumonia incidence in intensive care units: a surveillance-based study.

BACKGROUND: The incidence of ventilator-associated pneumonia (VAP) within the first 48 hours of intensive care unit (ICU) stay has been poorly investigated. The objective was to estimate early-onset VAP occurrence in ICUs within 48 hours after admission. METHODS: We analyzed data from prospective surveillance between 01/01/2001 and 31/12/2009 in 11 ICUs of Lyon hospitals (France). The inclusion criteria were: first ICU admission, not hospitalized before admission, invasive mechanical ventilation during first ICU day, free of antibiotics at admission, and ICU stay ≥ 48 hours. VAP was defined according to a national protocol. Its incidence was the number of events per 1,000 invasive mechanical ventilation-days. The Poisson regression model was fitted from day 2 (D2) to D8 to incident VAP to estimate the expected VAP incidence from D0 to D1 of ICU stay. RESULTS: Totally, 367 (10.8%) of 3,387 patients in 45,760 patient-days developed VAP within the first 9 days. The predicted cumulative VAP incidence at D0 and D1 was 5.3 (2.6-9.8) and 8.3 (6.1-11.1), respectively. The predicted cumulative VAP incidence was 23.0 (20.8-25.3) at D8. The proportion of missed VAP within 48 hours from admission was 11% (9%-17%). CONCLUSIONS: Our study indicates underestimation of early-onset VAP incidence in ICUs, if only VAP occurring ≥ 48 hours are considered to be hospital-acquired. Clinicians should be encouraged to develop a strategy for early detection after ICU admission.

Estimating attributable mortality due to nosocomial infections acquired in intensive care units.

BACKGROUND: The strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken. OBJECTIVE: To assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients. SETTING: Eleven ICUs of a French university hospital. DESIGN: We analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was defined as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis. RESULTS: Among 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%-14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%-6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%-3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%-2.5%) for bloodstream infection, and 0.0% (95% CI, -0.4% to 0.4%) for urinary tract infection. CONCLUSIONS: ICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.

Early- and late-onset ventilator-associated pneumonia acquired in the intensive care unit: comparison of risk factors.

PURPOSE: To compare risk factors of early- (E) and late-onset (L) ventilator-associated pneumonia (VAP). MATERIALS AND METHODS: An epidemiological survey based on a nosocomial infection surveillance program of 11 intensive care units (ICUs) of university teaching hospitals in Lyon, France, was conducted. A total of 7236 consecutive ventilated patients, older than 18 years and hospitalized in ICUs for at least 48 hours, were studied between 1996 and 2002. Data during ICU stay, patient-dependent risk factors, device exposure, nosocomial infections occurrence, and outcome were collected. The cutoff point definition between E-VAP (six days) was based on the daily hazard rate of VAP. RESULTS: The VAP incidence rate was 13.1%, 356 (37.6%) E-VAP (within 6 days of admission) and 590 (62.4%) L-VAP were reported. Independent risk factor for E-VAP vs L-VAP was surgical diagnostic category (odds ratio [OR], 1.49 [95% confidence interval, 1.07-2.07]), whereas independent risk factors for L-VAP vs E-VAP were older age (OR, 1.01 [1.01-1.02]), high Simplified Acute Physiology Score II (OR, 1.01 [1.00-1.02]), infection on admission (OR=2.22 [1.61-3.03]), another nosocomial infection before VAP (OR, 5.88 [3.33-11.11]), and exposure to central venous catheter before VAP (OR, 4.76 [1.04-20.00]). CONCLUSIONS: E-VAP and L-VAP have different risk factors, highlighting the need for developing specific preventive measures.

FcgammaRIIIb and complement component C7 codeficiency in a patient with recurrence of fulminant meningococcal septic shock.

Individuals with deficiencies of the late components of complement exhibit a susceptibility to the recurrence of meningococcal disease with a usually mild clinical presentation. We report the recurrence of fulminant meningococcal disease in a complement component C7-deficient patient. We found a total deficiency of FcgammaRIIIb on neutrophils, which could partially explain the unusually severe clinical presentation.

Does continuous positive airway pressure by face mask improve patients with acute cardiogenic pulmonary edema due to left ventricular diastolic dysfunction?

OBJECTIVE: Continuous positive airway pressure (CPAP) by face mask is an effective method of treating severe cardiogenic pulmonary edema (CPE). However, to our knowledge, no study has provided a precise evaluation of the effects of CPAP on cardiac function in patients presenting with CPE and preserved left ventricular (LV) function. DESIGN: Prospective observational clinical study. SETTING: A 14-bed, medical ICU at a university hospital. PATIENTS: Nine consecutive patients presenting with hypoxemic acute CPE. INTERVENTIONS: All patients were selected for 30 min of CPAP with 10 cm H(2)O by mask with fraction of inspired oxygen adjusted for a cutaneous saturation > 90%. Doppler echocardiography was performed before CPAP application and during the last 10 min of breathing with CPAP. Two-tailed, paired t-tests were used to compare data recorded at baseline (oxygen alone) and after CPAP. MEASUREMENTS AND RESULTS: Four patients presented CPE with preserved left ventricular (LV) function (a preserved LV ejection fraction [LVEF] > 45%, and/or aortic velocity time integral > 17 cm in the absence of aortic stenosis or hypertrophic cardiomyopathy). Oxygenation and ventilatory parameters were improved by CPAP in all patients. Hemodynamic monitoring and Doppler echocardiographic analysis demonstrated that in patients with preserved LV systolic function, mean arterial pressure and LV end-diastolic volume were decreased significantly by CPAP (p < 0.04). In patients with LV systolic dysfunction, CPAP improved LVEF (p < 0.05) and decreased LV end-diastolic volume (p = 0.001) significantly. CONCLUSION: CPAP improves oxygenation and ventilatory parameters in all kinds of CPE. In patients with preserved LV contractility, the hemodynamic benefit of CPAP results from a decrease in LV end-diastolic volume (preload).

Correlation between measured inferior vena cava diameter and right atrial pressure depends on the echocardiographic method used in patients who are mechanically ventilated.

In patients who are mechanically ventilated, the correlation between inferior vena cava diameter (IVCD) measurements and mean right atrial pressure (RAP) varies in the literature. The purpose of this study was to test if the correlation between IVCD and RAP measurement in patients who are critically ill depends on the transthoracic echocardiography (TTE) methodology used. Twenty patients who were critically ill, sedated, and required respiratory support were prospectively studied by TTE during mechanical ventilation in a controlled mode. The TTE measures of IVCD were made, using methods previously cited. First, IVCD was measured at end-expiration and end-diastole, with ECG synchronization, using the M-mode, on short-axis view 2 cm below the right atrium. Second, IVCD was assessed at end-expiration, without ECG synchronization, using the 2-dimensional long-axis view at the same location. RAP was measured simultaneously by using a central venous catheter positioned in the superior vena cava. All measurements were taken in the supine position. IVCD at end-expiration and end-diastole, with ECG synchronization, using the M-mode, and IVCD at end-expiration, without ECG synchronization, using the 2-dimensional long-axis view, correlate linearly with RAP (0.81, P <.0001 and 0.71, P =.0004). Mean bias between the 2 TTE methods (Bland-Altman analysis) was 1.6 mm (SD +/- 2.03 mm). In conclusion, this study confirms that variation of correlation between TTE IVCD measurement and RAP depends on the ultrasonographic methodology used and the timing of measurement during the cardiac cycle. IVCD at end-expiration and end-diastole, with ECG synchronization, using the M-mode (IVCD-MM) correlates more satisfactory with RAP than with IVCD at end-expiration, without ECG synchronization, using the 2-dimensional long-axis view, in patients during mechanical ventilation.

Physiological effects of constant versus decelerating inflation flow in patients with chronic obstructive pulmonary disease under controlled mechanical ventilation.

OBJECTIVE: To study the cardiorespiratory effects of inspiratory flow rate and waveform in COPD patients. DESIGN: Prospective physiological investigation with randomized allocations of experimental conditions. SETTING: A 14-bed medical ICU in a 1000-bed university hospital. PATIENTS AND PARTICIPANTS: Ten COPD intubated, sedated and paralyzed patients with chronic obstructive pulmonary disease (COPD), mechanically ventilated for acute respiratory failure. INTERVENTIONS: In volume-controlled mode, three inflation flow rates of 0.40, 0.70, and 1.10 l/s for 20 min with a constant (CF) or a decelerating (DF) inflation flow profile. Each patient received all six experimental conditions in a random order. Tidal volume and respiratory frequency were similar during the experimental conditions. MEASUREMENTS AND RESULTS: Arterial blood gases, hemodynamics ( n=8), and respiratory mechanics were measured with zero end expiratory pressure. Between flow rates the median (25th-75th percentiles) values of PaO(2)/FIO(2) were 232 (132-289), 253 (161-338), 231 (163-352) for CF and 253 (143-331), 249 (164-360), 231 mmHg (187-351), for DF, respectively; the maximal airway pressures were 25.6, 28.3, 34.6 cmH(2)O for CF and 21.7, 29.6, 34.8 cmH(2)O for DF, respectively, the mean airway pressures were 8.9, 6.1, 5.4 cmH(2)O for CF and 9.1, 7, 6.5 cmH(2)O for DF, respectively. CONCLUSIONS: Changing the ventilator in volume-controlled mode with a DF or CF profile has no significant cardiorespiratory effect in intubated COPD patients mechanically ventilated for acute respiratory failure.