Respiratory failure & ventilation
Impact of cardiac output and alveolar ventilation in estimating ventilation/perfusion mismatch in ARDS using electrical impedance tomography
Authors' conclusion
Neglecting cardiac output and alveolar ventilation when assessing V/Q mismatch indices using EIT in ARDS patients results in significant bias, whose direction depends on the VA/QC ratio value.
Study context
- Population
- ARDS patients assessed with electrical impedance tomography21 with ventilation (VA)/QC > 1
- Participants
- 25 patients
- Comparison
- Relative V/Q map vs absolute V/Q map
- Outcome
- V/Q mismatch indices in patients with VA/QC > 1
Main finding
As reported in the abstract
| Group | Value | Shunt fraction | Dead space fraction | Wasted ventilation | Wasted perfusion |
|---|---|---|---|---|---|
| Relative | 37% (range not specified 24–66) | 37% (24-66) | 40% (22-49) | 16% (11-27) | 18% (11-23) |
| Absolute | 19% (range not specified 11–46) | 19% (11-46) | 58% (46-84) | 29% (19-35) | 11% (7-19) |
Value
Relative37% (range not specified 24–66)
Absolute19% (range not specified 11–46)
Shunt fraction
Relative37% (24-66)
Absolute19% (11-46)
Dead space fraction
Relative40% (22-49)
Absolute58% (46-84)
Wasted ventilation
Relative16% (11-27)
Absolute29% (19-35)
Wasted perfusion
Relative18% (11-23)
Absolute11% (7-19)
- Relative vs Absolute: P < 0.001 — shunt fraction significantly higher
- Relative vs Absolute: P < 0.001 — dead space fraction significantly lower
- Relative vs Absolute: P < 0.001 — wasted ventilation significantly lower
- Relative vs Absolute: P < 0.001 — wasted perfusion significantly higher
Further findings
V/Q mismatch indices in patients with VA/QC < 1 (subgroup)
- Opposite findings in the four patients with VA/QC < 1
Original publication
Impact of cardiac output and alveolar ventilation in estimating ventilation/perfusion mismatch in ARDS using electrical impedance tomography. Crit Care. Published 8 May 2023. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →