12 Oct 09
Posted in Mechanical ventilation, VAP at 14:04 by Laci
By W Melsen, M Rovers, M Bonten
Crit Care Med 2009; 37:2709-2718
To determine the attributable mortality of ventilator-associated pneumonia in a systematic review and meta-analysis of observational studies. Ventilator-associated pneumonia is generally believed to increase the mortality of patients. This notion is predominantly based on the results of observational studies.
Data source
We performed a systematic search strategy using PubMed, Web of Science, and Embase from their inception through February 2007. In addition, a reference and related article search was performed.
Study selection
Studies were included if they reported mortality rates of patients with and without ventilator-associated pneumonia.
Data extraction and synthesis
Fifty-two studies with a total of 17,347 patients met the inclusion criteria. Pooling of all studies resulted in relative risk of 1.27 (95% Confidence Interval = 1.15-1.39), but heterogeneity was considerable (I2 statistic = 69%). The origin of heterogeneity could not be explained by differences in study design, study quality, and diagnostic approach. However, heterogeneity was limited for studies investigating only trauma patients (I2 = 1.3%) or patients with acute respiratory distress syndrome (I2 = 0%), with estimated relative risk of 1.09 (95% Confidence Interval = 0.87-1.37) among trauma patients and 0.86 (95% Confidence Interval = 0.72-1.04) among patients with acute respiratory distress syndrome.
Conclusions
There is no evidence of attributable mortality due to ventilator-associated pneumonia in patients with trauma or acute respiratory distress syndrome. However, in other nonspecified patient groups, there is evidence for attributable mortality due to ventilator-associated pneumonia, but this could not be quantified due to heterogeneity in study results. More detailed studies, allowing subgroup analyses, are needed to determine the attributable mortality of ventilator-associated pneumonia in these patient populations.
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25 May 09
Posted in Echocardiography, Mechanical ventilation at 2:15 by Laci
By B Lamia, J Maizel, A Ochagavia, D Chemla, D Osman, C Richard, JL Teboul
Crit Care Med 2009; 37:1696-1701
Weaning-induced pulmonary edema is a cause of weaning failure in high-risk patients. The diagnosis may require pulmonary artery catheterization to demonstrate increased pulmonary artery occlusion pressure (PAOP) during weaning. Transthoracic echocardiography can estimate left ventricular filling pressures using early (E) and late (A) peak diastolic velocities measured with Doppler transmitral flow, and tissue Doppler imaging of mitral annulus velocities including early (Ea) peak diastolic velocity. We tested the hypothesis that E/A and E/Ea could be used to detect weaning-induced PAOP elevation defined by a PAOP >=18 mm Hg during a spontaneous breathing trial (SBT).
Measurements and main results
We included 39 patients who previously failed two consecutive SBTs. A third SBT was performed over a maximum 1-hour period using a T-piece. The PAOP, E/A, and E/Ea were measured before and during this SBT. Receiver operating characteristic curves were constructed to determine the optimal sensitivity and specificity values of E/A and E/Ea obtained at the end of the SBT for predicting a weaning-induced PAOP elevation. Weaning-induced PAOP elevation occurred in 17 patients. A value of E/A >0.95 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 88% and a specificity of 68%. A value of E/Ea >8.5 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 94% and a specificity of 73%. The combination of E/A >0.95 and E/Ea >8.5 predicted a weaning-induced PAOP elevation with a sensitivity of 82% and a specificity of 91%.
Conclusion
At the end of an SBT, the combination of E/A >0.95 and E/Ea >8.5 measured with transthoracic echocardiography allowed an accurate noninvasive detection of weaning-induced PAOP elevation.
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04 Mar 09
Posted in Mechanical ventilation, Sedation at 0:48 by Laci
By R R Riker, Y Shehabi, P M Bokesch, D Ceraso, W Wisemandle, F Koura, P Whitten, B D Margolis, D W Byrne, E Wesley Ely et al for the SEDCOM (Safety and Efficacy of Dexmedetomidine Compared With Midazolam) Study Group
JAMA. 2009;301:489-499
Aminobutyric acid receptor agonist medications are the most commonly used sedatives for intensive care unit (ICU) patients, yet preliminary evidence indicates that the {alpha}2 agonist dexmedetomidine may have distinct advantages.
Objective
To compare the efficacy and safety of prolonged sedation with dexmedetomidine vs midazolam for mechanically ventilated patients.
Design, setting and patients
Prospective, double-blind, randomized trial conducted in 68 centers in 5 countries between March 2005 and August 2007 among 375 medical/surgical ICU patients with expected mechanical ventilation for more than 24 hours. Sedation level and delirium were assessed using the Richmond Agitation-Sedation Scale (RASS) and the Confusion Assessment Method for the ICU.
Interventions
Dexmedetomidine (0.2-1.4 µg/kg per hour [n = 244]) or midazolam (0.02-0.1 mg/kg per hour [n = 122]) titrated to achieve light sedation (RASS scores between –2 and +1) from enrollment until extubation or 30 days.
Main outcome measures
Percentage of time within target RASS range. Secondary end points included prevalence and duration of delirium, use of fentanyl and open-label midazolam, and nursing assessments. Additional outcomes included duration of mechanical ventilation, ICU length of stay, and adverse events.
Results
There was no difference in percentage of time within the target RASS range (77.3% for dexmedetomidine group vs 75.1% for midazolam group; difference, 2.2% [95% confidence interval {CI}, –3.2% to 7.5%]; P = .18). The prevalence of delirium during treatment was 54% (n = 132/244) in dexmedetomidine-treated patients vs 76.6% (n = 93/122) in midazolam-treated patients (difference, 22.6% [95% CI, 14% to 33%]; P < .001). Median time to extubation was 1.9 days shorter in dexmedetomidine-treated patients (3.7 days [95% CI, 3.1 to 4.0] vs 5.6 days [95% CI, 4.6 to 5.9]; P = .01), and ICU length of stay was similar (5.9 days [95% CI, 5.7 to 7.0] vs 7.6 days [95% CI, 6.7 to 8.6]; P = .24). Dexmedetomidine-treated patients were more likely to develop bradycardia (42.2% [103/244] vs 18.9% [23/122]; P < .001), with a nonsignificant increase in the proportion requiring treatment (4.9% [12/244] vs 0.8% [1/122]; P = .07), but had a lower likelihood of tachycardia (25.4% [62/244] vs 44.3% [54/122]; P < .001) or hypertension requiring treatment (18.9% [46/244] vs 29.5% [36/122]; P = .02).
Conclusions
There was no difference between dexmedetomidine and midazolam in time at targeted sedation level in mechanically ventilated ICU patients. At comparable sedation levels, dexmedetomidine-treated patients spent less time on the ventilator, experienced less delirium, and developed less tachycardia and hypertension. The most notable adverse effect of dexmedetomidine was bradycardia.
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06 Feb 09
Posted in Infection, Mechanical ventilation at 0:45 by Laci
By Caruso, S Denari, SA Ruiz, SE Demarzo, D Deheinzelin
Critical Care Medicine 2009;37:32-38
To compare the incidence of ventilator-associated pneumonia (VAP) with or without isotonic saline instillation before tracheal suctioning. As a secondary objective, we compared the incidence of endotracheal tube occlusion and atelectasis.
Design
Randomized clinical trial.
Setting and patients
The study was conducted in a medical surgical intensive care unit of an oncologic hospital. We selected consecutive patients needing mechanical ventilation for >72 hrs. Patients were allocated into two groups: a saline group that received instillation of 8 mL of saline before tracheal suctioning and a control group which did not. VAP was diagnosed based on clinical suspicion and confirmed by bronchoalveolar lavage quantitative culture. The incidence of atelectasis on daily chest radiography and endotracheal tube occlusions were recorded. The sample size was calculated to a power of 80% and a type I error probability of 5%.
Measurements and main results
One hundred thirty patients were assigned to the saline group and 132 to the control group. The baseline demographic variables were similar between groups. The rate of clinically suspected VAP was similar in both groups. The incidence of microbiological proven VAP was significantly lower in the saline group (23.5% × 10.8%; p = 0.008) (incidence density/1.000 days of ventilation 21.22 × 9.62; p < 0.01). Using the Kaplan-Meier curve analysis, the proportion of patients remaining without VAP was higher in the saline group (p = 0.02, log-rank test). The relative risk reduction of VAP in the saline instillation group was 54% (95% confidence interval, 18%-74%) and the number needed to treat was eight (95% confidence interval, 5-27). The incidence of atelectases and endotracheal tube occlusion were similar between groups.
Conclusions
Instillation of isotonic saline before tracheal suctioning decreases the incidence of microbiological proven VAP.
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