Monitoring of tidal ventilation by electrical impedance tomography in anaesthetised horses.
Authors: Mosing M, Waldmann A D, Raisis A, Böhm S H, Drynan E, Wilson K
Journal: Equine veterinary journal
Summary
Electrical impedance tomography (EIT) offers a non-invasive means of monitoring regional lung ventilation by detecting impedance shifts within the thorax, yet its application in equine anaesthesia has remained unexplored until now. Mosing and colleagues evaluated whether EIT could accurately quantify tidal volume changes in six anaesthetised, mechanically ventilated horses by systematically altering ventilator settings from 4–16 mL/kg whilst simultaneously recording measurements via conventional spirometry and EIT sensors. Both regional lung impedance (EITROI) and whole-thorax impedance (EITthorax) demonstrated strong linear relationships with spirometry-derived tidal volumes, with individual horse correlations reaching R² values of 0.937–0.999, and pooled analysis yielding R² values of 0.799–0.841—suggesting EIT can reliably detect ventilation changes across different tidal volume ranges. Although the research was limited to healthy horses under controlled mechanical ventilation, these findings suggest EIT could provide real-time, regional monitoring of ventilation distribution during equine anaesthesia, potentially allowing clinicians to detect hypoventilation or uneven lung inflation and adjust management accordingly. Further investigation in clinical settings and with varied respiratory pathology would be required before EIT becomes a practical adjunct to standard monitoring in equine practice.
Read the full abstract on PubMed
Practical Takeaways
- •EIT offers a non-invasive, real-time method to monitor ventilation adequacy in anaesthetised horses during mechanical ventilation, potentially replacing or complementing spirometry
- •The technique showed robust correlation across individual horses and pooled populations, suggesting clinical applicability for monitoring anaesthetic cases
- •Further validation in non-healthy or spontaneously breathing horses is needed before routine clinical adoption
Key Findings
- •EIT successfully predicted spirometry-measured tidal volumes in individual horses with R² values ranging from 0.937–0.999 for lung regions and 0.954–0.997 for whole thorax
- •Pooled data from all six horses showed EIT could predict tidal volume changes with R² = 0.799 (lung regions) and R² = 0.841 (whole thorax)
- •Both regional (EITROI) and whole thorax (EITthorax) impedance measurements provided reliable quantification of tidal volume changes across 1 L increments