Auto-PEEP and dynamic hyperinflation in COPD patients during controlled mechanical ventilation and high frequency jet ventilation.
We investigated the levels of auto-PEEP and dynamic hyperinflation during high frequency jet ventilation (HFJV) and controlled mechanical ventilation (CMV) in six patients with chronic obstructive pulmonary disease within the first 36 h of acute exacerbation. The comparative evaluation was performed at similar conditions of gas exchange in HFJV and CMV: PaO2 77.6 +/- 11 mmHg vs 80.8 +/- 12 mmHg; PaCO2 46.8 +/- 2.5 mmHg vs 47 +/- 2.8 mmHg; pH 7.38 vs 7.38. In this situation, the values of auto-PEEP and dynamic hyperinflation, expressed as delta over the apneic functional residual capacity (FRC) did not differ: (auto-PEEPHFJV 8.9 +/- 3.8 cmH2O; auto-PEEPCMV 8.8 +/- 4.7 cmH2O; delta FRCHFJV 0.56 +/- 0.19 l; delta FRCCMV 0.54 +/- 0.2 l). This result suggests that, with a suitable machine setting and similar gas exchanges, HFJV produces the same level of auto-PEEP and dynamic hyperinflation as CMV in patients with chronic obstructive pulmonary disease.
Istituto di Anestesia e Rianimazione, Università La Sapienza, Rome, Italy.
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Conti
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Bufi
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Rocco
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Calzecchi
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De Blasi
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Antonelli
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Pelaia
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Gasparetto
D000368:Aged; D000403:Airway Resistance; D005105:Expiratory Reserve Volume; D005260:Female; D005652:Functional Residual Capacity; D006611:High-Frequency Jet Ventilation / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008170:Lung Compliance; D008173:Lung Diseases, Obstructive / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011175:Positive-Pressure Respiration