TABLE 2.

Transcutaneous Carbon Dioxide Versus Paco₂ Agreement at Low, Normal, and High Paco₂ Levels

CO2 Range	Paco2 < 30 mm Hg, n = 93, n (%)	Paco2 30–50 mm Hg, n = 1316, n (%)	Paco2 > 50 mm Hg, n = 1998, n (%)
Tcco2 < 30 mm Hg (n = 36)	21 (22.6)	14 (1.1)	1 (0.1)
Tcco2 30–50 mm Hg (n = 1115)	62 (66.7)	908 (69)	145 (7.2)
Tcco2 > 50 mm Hg (n = 2256)	10 (10.8)	394 (30)	1852 (92.7)

n = number of sample pairs within range, Paco₂ = partial pressure of carbon dioxide, Tcco₂ = transcutaneous carbon dioxide.

Ranges for both Paco₂ and Tcco₂ are as follows: low < 30 mm Hg, normal 30–50 mm Hg, and high > 50 mm Hg.

Percentages are calculated from a total (n) for each of the following: low Tcco₂, normal Tcco₂, and high Tcco_2.

Weighted Cohen’s Kappa = 0.40 (95% CI, 0.31–0.50).