Electrical impedance tomography monitoring in acute respiratory distress syndrome patients with mechanical ventilation during prolonged positive end-expiratory pressure adjustments

Chia Fu Hsu, Jen Suo Cheng, Wei-Chieh Lin, Yen Fen Ko, Kuo-Sheng Cheng, Sheng-Hsiang Lin, Chang-Wen Chen

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Abstract

Background/purpose: The time required to reach oxygenation equilibrium after positive end-expiratory pressure (PEEP) adjustments in mechanically ventilated patients with acute respiratory distress syndrome (ARDS) is unclear. We used electrical impedance tomography to elucidate gas distribution and factors related to oxygenation status following PEEP in patients with ARDS. Methods: Nineteen mechanically ventilated ARDS patients were placed on baseline PEEP (PEEP B ) for 1 hour, PEEP B - 4 cmH 2 O PEEP (PEEP L ) for 30 minutes, and PEEP B + 4 cmH 2 O PEEP (PEEP H ) for 1 hour. Tidal volume and respiratory rate were similar. Impedance changes, respiratory parameters, and arterial blood gases were measured at baseline, 5 minutes, and 30 minutes after PEEP L , and 5 minutes, 15 minutes, 30 minutes, and 1 hour after PEEP H . Results: PaO 2 /fraction of inspired oxygen (P/F ratio) decreased quickly from PEEP B to PEEP L , and stabilized 5 minutes after PEEP L . However the P/F ratio progressively increased from PEEP L to PEEP H , and a significantly higher P/F ratio and end-expiratory lung impedance were found at 60 minutes compared to 5 minutes after PEEP H . The end-expiratory lung impedance level significantly correlated with P/F ratio (p < 0.001). With increasing PEEP, dorsal ventilation significantly increased; however, regional ventilation did not change over time with PEEP level. Conclusion: Late improvements in oxygenation following PEEP escalation are probably due to slow recruitment in ventilated ARDS patients. Electrical impedance tomography may be an appropriate tool to assess recruitment and oxygenation status in patients with changes in PEEP.

Original languageEnglish
Pages (from-to)195-202
Number of pages8
JournalJournal of the Formosan Medical Association
Volume115
Issue number3
DOIs
Publication statusPublished - 2016 Mar 1

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Positive-Pressure Respiration
Adult Respiratory Distress Syndrome
Electric Impedance
Artificial Respiration
Tomography
Oxygen
Ventilation
Gases

All Science Journal Classification (ASJC) codes

  • Medicine(all)

Cite this

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title = "Electrical impedance tomography monitoring in acute respiratory distress syndrome patients with mechanical ventilation during prolonged positive end-expiratory pressure adjustments",
abstract = "Background/purpose: The time required to reach oxygenation equilibrium after positive end-expiratory pressure (PEEP) adjustments in mechanically ventilated patients with acute respiratory distress syndrome (ARDS) is unclear. We used electrical impedance tomography to elucidate gas distribution and factors related to oxygenation status following PEEP in patients with ARDS. Methods: Nineteen mechanically ventilated ARDS patients were placed on baseline PEEP (PEEP B ) for 1 hour, PEEP B - 4 cmH 2 O PEEP (PEEP L ) for 30 minutes, and PEEP B + 4 cmH 2 O PEEP (PEEP H ) for 1 hour. Tidal volume and respiratory rate were similar. Impedance changes, respiratory parameters, and arterial blood gases were measured at baseline, 5 minutes, and 30 minutes after PEEP L , and 5 minutes, 15 minutes, 30 minutes, and 1 hour after PEEP H . Results: PaO 2 /fraction of inspired oxygen (P/F ratio) decreased quickly from PEEP B to PEEP L , and stabilized 5 minutes after PEEP L . However the P/F ratio progressively increased from PEEP L to PEEP H , and a significantly higher P/F ratio and end-expiratory lung impedance were found at 60 minutes compared to 5 minutes after PEEP H . The end-expiratory lung impedance level significantly correlated with P/F ratio (p < 0.001). With increasing PEEP, dorsal ventilation significantly increased; however, regional ventilation did not change over time with PEEP level. Conclusion: Late improvements in oxygenation following PEEP escalation are probably due to slow recruitment in ventilated ARDS patients. Electrical impedance tomography may be an appropriate tool to assess recruitment and oxygenation status in patients with changes in PEEP.",
author = "Hsu, {Chia Fu} and Cheng, {Jen Suo} and Wei-Chieh Lin and Ko, {Yen Fen} and Kuo-Sheng Cheng and Sheng-Hsiang Lin and Chang-Wen Chen",
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TY - JOUR

T1 - Electrical impedance tomography monitoring in acute respiratory distress syndrome patients with mechanical ventilation during prolonged positive end-expiratory pressure adjustments

AU - Hsu, Chia Fu

AU - Cheng, Jen Suo

AU - Lin, Wei-Chieh

AU - Ko, Yen Fen

AU - Cheng, Kuo-Sheng

AU - Lin, Sheng-Hsiang

AU - Chen, Chang-Wen

PY - 2016/3/1

Y1 - 2016/3/1

N2 - Background/purpose: The time required to reach oxygenation equilibrium after positive end-expiratory pressure (PEEP) adjustments in mechanically ventilated patients with acute respiratory distress syndrome (ARDS) is unclear. We used electrical impedance tomography to elucidate gas distribution and factors related to oxygenation status following PEEP in patients with ARDS. Methods: Nineteen mechanically ventilated ARDS patients were placed on baseline PEEP (PEEP B ) for 1 hour, PEEP B - 4 cmH 2 O PEEP (PEEP L ) for 30 minutes, and PEEP B + 4 cmH 2 O PEEP (PEEP H ) for 1 hour. Tidal volume and respiratory rate were similar. Impedance changes, respiratory parameters, and arterial blood gases were measured at baseline, 5 minutes, and 30 minutes after PEEP L , and 5 minutes, 15 minutes, 30 minutes, and 1 hour after PEEP H . Results: PaO 2 /fraction of inspired oxygen (P/F ratio) decreased quickly from PEEP B to PEEP L , and stabilized 5 minutes after PEEP L . However the P/F ratio progressively increased from PEEP L to PEEP H , and a significantly higher P/F ratio and end-expiratory lung impedance were found at 60 minutes compared to 5 minutes after PEEP H . The end-expiratory lung impedance level significantly correlated with P/F ratio (p < 0.001). With increasing PEEP, dorsal ventilation significantly increased; however, regional ventilation did not change over time with PEEP level. Conclusion: Late improvements in oxygenation following PEEP escalation are probably due to slow recruitment in ventilated ARDS patients. Electrical impedance tomography may be an appropriate tool to assess recruitment and oxygenation status in patients with changes in PEEP.

AB - Background/purpose: The time required to reach oxygenation equilibrium after positive end-expiratory pressure (PEEP) adjustments in mechanically ventilated patients with acute respiratory distress syndrome (ARDS) is unclear. We used electrical impedance tomography to elucidate gas distribution and factors related to oxygenation status following PEEP in patients with ARDS. Methods: Nineteen mechanically ventilated ARDS patients were placed on baseline PEEP (PEEP B ) for 1 hour, PEEP B - 4 cmH 2 O PEEP (PEEP L ) for 30 minutes, and PEEP B + 4 cmH 2 O PEEP (PEEP H ) for 1 hour. Tidal volume and respiratory rate were similar. Impedance changes, respiratory parameters, and arterial blood gases were measured at baseline, 5 minutes, and 30 minutes after PEEP L , and 5 minutes, 15 minutes, 30 minutes, and 1 hour after PEEP H . Results: PaO 2 /fraction of inspired oxygen (P/F ratio) decreased quickly from PEEP B to PEEP L , and stabilized 5 minutes after PEEP L . However the P/F ratio progressively increased from PEEP L to PEEP H , and a significantly higher P/F ratio and end-expiratory lung impedance were found at 60 minutes compared to 5 minutes after PEEP H . The end-expiratory lung impedance level significantly correlated with P/F ratio (p < 0.001). With increasing PEEP, dorsal ventilation significantly increased; however, regional ventilation did not change over time with PEEP level. Conclusion: Late improvements in oxygenation following PEEP escalation are probably due to slow recruitment in ventilated ARDS patients. Electrical impedance tomography may be an appropriate tool to assess recruitment and oxygenation status in patients with changes in PEEP.

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DO - 10.1016/j.jfma.2015.03.001

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VL - 115

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EP - 202

JO - Journal of the Formosan Medical Association

JF - Journal of the Formosan Medical Association

SN - 0929-6646

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