1. Effect of decreased inspiratory times on tidal volume
- Author
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Herff, H., Bowden, K., Paal, P., Mitterlechner, T., von Goedecke, A., Lindner, K.H., and Wenzel, V.
- Abstract
Abstract: Background: During cardiopulmonary resuscitation (CPR) with a chest compression rate of 60–100/min the time for secure undisturbed ventilation in the chest decompression phase is only 0.3–0.5 s and it is unclear which tidal volumes could be delivered in such a short time. Objectives: Attempts were made to assess the tidal volumes that can be insufflated in such a short time window. Methods: In a bench model tidal volumes were compared in simulated non-intubated and intubated patients employing an adult self-inflating bag-valve with inspiratory times of 0.25, 0.3, and 0.5 s. Respiratory system compliance values were 60 mL/cmH
2 O being representative for respiratory system conditions shortly after onset of cardiac arrest and 20 mL/cmH2 O being representative for conditions after prolonged cardiac arrest. Results: With a respiratory system compliance of 60 mL/cmH2 O, tidal volumes (mean±SD) in non-intubated versus intubated patients were 144±13 mL versus 196±23 mL in 0.25 s (p<0.01), 178±10 versus 270±14 mL in 0.3 s (p<0.01), and 310±12 mL versus 466±20 mL in 0.5 s (p<0.01). With a respiratory system compliance of 20 mL/cmH2 O, tidal volumes in non-intubated patient versus intubated patients were 128±10 mL versus 186±20 mL in 0.25 s (p<0.01), 158±17 versus 250±14 mL in 0.3 s (p<0.01) and 230±21 mL versus 395±20 mL in 0.5 s (p<0.01). Conclusions: Ventilation windows of 0.25, 0.3, and 0.5 s were too short to provide adequate tidal volumes in a simulated non-intubated cardiac arrest patient. In a simulated intubated cardiac arrest patient, ventilation windows of at least 0.5 s were necessary to provide adequate tidal volumes.- Published
- 2024
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