1,720,962 research outputs found
Assessing gas exchange in acute lung injury/acute respiratory distress syndrome : diagnostic techniques and prognostic relevance
No full textPurpose of review
To provide the most recent insights on the assessment of gas exchange in acute lung
injury.
Recent findings
Central venous blood may be used as a surrogate of arterial blood to assess carbon
dioxide tension and acid–base status. In contrast arterial oxygenation cannot be
estimated with confidence from venous blood. However, the use of venous blood
associated with pulse oximetry may provide the SvO2 which is useful for monitoring and
targeting the resuscitation therapy. Impaired CO2 clearance and increased dead space
have been confirmed as useful prognostic indices of structural lung damage and
mortality in acute respiratory failure. A simplified technique based on multiple inert gas
technique has been described to assess ventilation–perfusion mismatch while a new
analysis of pulse oximetry has been suggested to detect lung opening and closing.
Finally, new insight has been provided on the relationship between lung anatomy, as
detected by computed tomography, oxygenation and CO2 clearance.
Summary
Although oxygenation assessment is of primary importance during respiratory lung
injury, dead space and CO2 retention are more strictly associated with outcome. The
association of central venous blood analysis and pulse oximetry may provide more
information than arterial blood alone
Recruitability, recruitment, and tidal volume interactions: is biologically variable ventilation a possible answer?
No full text
Comparison of a novel lycra endotracheal tube cuff to standard polyvinyl chloride cuff and polyurethane cuff for fluid leak prevention
No full textBACKGROUND: A high-volume low-pressure endotracheal tube (ETT) cuff forms folds along its contact with the trachea, allowing mucus leakage into the lungs. We developed a thin-walled ETT cuff made of Lycra polyurethane. METHODS: In vitro, we tested 6 of each of the new prototype Lycra cuff, the Mallinkrodt Hi-Lo ETT (polyvinyl chloride cuff), and the Kimberly-Clark Microcuff ETT (polyurethane cuff), for leakage, in an acrylic mock trachea (inner diameter 20-mm), with a cuff inflation pressure of 20 cm H2O. We poured 15 mL of methylene-blue colored water into the acrylic tube above the cuff and observed for leakage for 24 hours. RESULTS: The Lycra cuffs had no folds upon inflation in the mock trachea and completely prevented fluid leakage for 24 hours (P<.001 vs the Hi-Lo and the Microcuff). The average leakage past the Hi-Lo was 1,182±1,321 mL/h. The average leakage past the Microcuff was 1.2 ± 0.4 mL/h (P <.001 vs the Hi-Lo). CONCLUSIONS: Our Lycra cuff provided complete tracheal sealing in vitro
A radiological visual scale to predict the potentially recruitable lung in ALI/ARDS patients
No full textIntroduction In ALI/ARDS patients the amount of potentially
recruitable lung is extremely variable and it is poorly predictable by
the changes of oxygenation, carbon dioxide or compliance during a
PEEP trial [1]. At the present time the gold standard to compute the
lung recruitability is the quantitative lung CT scan, in which each lung image, after being manually drawn, is analyzed by dedicated software.
However, this is both a laborious and time-consuming technique. The
aim of this study was to evaluate the ability of a visual radiological scale
compared with lung CT scan analysis to predict the lung recruitability
in ALI/ARDS patients.
Methods A whole lung CT scan was performed at 5 and 45 cmH2O
airway pressure. For CT scan analysis each lung image was manually
outlined and analyzed by a dedicated software. The potentially
recruitable lung was defi ned as the proportion of the nonaerated
lung tissue in which aeration was restored [1]. For radiological visual
scale analysis, two radiologists performed a blinded evaluation of the
consolidation/collapsed areas in each lobe by visual inspection [2]. The
overall lung change in consolidation/collapsed was obtained by the
sum of each lobe and computed as the diff erence between the two
conditions.
Results Twenty-four ALI/ARDS patients (age 59 ± 15 years, BMI
26 ± 4 kg/m2, PaO2/FiO2 170 ± 60, PEEP 10 ± 2 cmH2O) were enrolled.
The percentage of potentially recruitable lung was 16.2 ± 7.1% and
14.7 ± 7.0%, computed by CT scan and by the visual radiological scale,
respectively. The mean diff erence between CT scan analysis and visual
radiological analysis was 3.3 ± 4.6% (median: 2.91, interquartile range:
0.38 to 6.56). The error of the visual method was lower than 5% in 14
patients (58.3%), between 5% and 10% in eight patients (33.3%) and
between 10% and 15% in two patients (8.3%).
Conclusions The application of a radiological visual scale is able to
predict the amount of potentially recruitable lung similarly to those
obtained by a dedicated software avoiding the need of manually
drawing each lung image.
References
1. Gattinoni L, et al.: N Engl J Med 2006, 354:1775-1786.
2. Pierce RJ, et al.: Thorax 1980, 35:773-780
Effetto delle raccomandazioni ARDSNetwork sulla gestione ventilatoria di pazienti affetti da ALI/ARDS
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Strain threshold for ventilator-induced lung injury
No full textIntroduction Unphysiological lung strain (tidal volume/functional residual capacity, TV/FRC) may cause ventilator-induced lung injury (VILI) [1]. Whether VILI develops proportionally to the applied strain or only above a critical threshold remains unknown. Methods In 20 healthy, mechanically ventilated pigs, FRC and lung weight were measured by computed tomography. Animals were then
ventilated for up to 54 hours with a TV set to produce a predetermined strain. At the end, lung weight was measured with a balance. VILI was defi ned as fi nal lung weight exceeding the initial one.
Results Lung weight either did not increase at all (no-VILI group; lung weight change –73 ± 42 g, n = 9) or markedly augmented (VILI group; 264 ± 80 g, n = 11). In the two groups, strain was 1.38 ± 0.68 and 2.16 ± 0.50 (P <0.01), respectively. VILI occurred only when lung strain reached or exceeded a critical threshold, between 1.5 and 2.1 (Figure 1). Conclusions In animals with healthy lungs VILI only occurs when lung strain exceeds a critical threshold. Reference 1. Gattinoni L, Carlesso E, Cadringher P, et al.: Physical and biological triggers of ventilator-induced lung injury and its prevention [review]. Eur Respir J 2003, 22(Suppl 47):15s-25s
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