Ventilation strategies for front of neck airway rescue: an in silico study
Background - During induction of general anaesthesia a ‘cannot intubate, cannot oxygenate’ (CICO) situation can arise, leading to severe hypoxaemia. Evidence is scarce to guide ventilation strategies for small-bore emergency front of neck airways that ensure effective oxygenation without risking lun...
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| Main Authors: | , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
3 March 2021
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| In: |
British journal of anaesthesia
Year: 2021, Volume: 126, Issue: 6, Pages: 1226-1236 |
| ISSN: | 1471-6771 |
| DOI: | 10.1016/j.bja.2021.01.030 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.bja.2021.01.030 Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0007091221000817 
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| Author Notes: | Marianna Laviola, Christian Niklas, Anup Das, Declan G. Bates and Jonathan G. Hardman |
| Summary: | Background - During induction of general anaesthesia a ‘cannot intubate, cannot oxygenate’ (CICO) situation can arise, leading to severe hypoxaemia. Evidence is scarce to guide ventilation strategies for small-bore emergency front of neck airways that ensure effective oxygenation without risking lung damage and cardiovascular depression. - Methods - Fifty virtual subjects were configured using a high-fidelity computational model of the cardiovascular and pulmonary systems. Each subject breathed 100% oxygen for 3 min and then became apnoeic, with an obstructed upper airway. When arterial haemoglobin oxygen saturation reached 40%, front of neck airway access was simulated with various configurations. We examined the effect of several ventilation strategies on re-oxygenation, pulmonary pressures, cardiovascular function, and oxygen delivery. - Results - Re-oxygenation was achieved in all ventilation strategies. Smaller airway configurations led to dynamic hyperinflation for a wide range of ventilation strategies. This effect was absent in airways with larger internal diameter (≥3 mm). Intrapulmonary pressures increased quickly to supra-physiological values with the smallest airways, resulting in pronounced cardio-circulatory depression (cardiac output <3 L min−1 and mean arterial pressure <60 mm Hg), impeding oxygen delivery (<600 ml min−1). Limiting tidal volume (≤200 ml) and ventilatory frequency (≤8 bpm) for smaller diameter cannulas reduced dynamic hyperinflation and gas trapping, preventing cardiovascular depression. - Conclusions - Dynamic hyperinflation can be demonstrated for a wide range of front of neck airway cannulae when the upper airway is obstructed. When using small-bore cannulae in a CICO situation, ventilation strategies should be chosen that prevent gas trapping to prevent severe adverse events including cardio-circulatory depression. |
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| Item Description: | Gesehen am 01.03.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1471-6771 |
| DOI: | 10.1016/j.bja.2021.01.030 |