Table 2 Agreement between the EIT-derived and TTE-derived SPAP estimates at the cohort-wise level.

From: Non-invasive pulmonary artery pressure estimation by electrical impedance tomography in a controlled hypoxemia study in healthy subjects

Cohort-wise measurements

TTE (mmHg)

EIT (mmHg)

EIT − TTE (mmHg)

All measurements combined (n = 166)

24.7 ± 6.6

24.6 ± 6.4

 − 0.1 ± 4.5†

Normoxemia (n = 70)

19.5 ± 2.9

19.5 ± 3.7

0.0 ± 2.6†

Mild hypoxemia (n = 48)

25.1 ± 4.3

26.3 ± 5.4

1.2 ± 4.5†

Profound hypoxemia (n = 48)

32.0 ± 5.2

30.4 ± 4.7

 − 1.6 ± 6.0†

  1. The distributions over the entire cohort (n = 166 paired measurements) are shown as “mean ± standard deviation”. The agreement is also depicted as a function of the oxygen saturation level (SpO2), comparing the distributions in normoxemia (SpO2 ≥ 95%), mild hypoxemia (90% > SpO2 ≥ 80%), and profound hypoxemia (80% > SpO2 ≥ 65%). In all cases, the distribution of the differences (EIT − TTE) between both methods showed to be non-significantly different from a zero-mean normal distribution at the 5% significance level.
  2. EIT electrical impedance tomography, TTE transthoracic echocardiography, SPAP systolic pulmonary artery pressure.
  3. †Paired-sample t-test: Not significant at the 5% significance level (P > 0.05).
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