| Diaphragm weakness | ||
| Diagnosed as weak (%) | SE (95% CI) | |
| (1) Sniff Pdi | 68.2 (180/264) | 2.87 (62.5 to 73.8) |
| (2) Twitch Pdi | 67.4 (178/264) | 2.89 (61.7 to 73.1) |
| (3) Sniff Pdi + Twitch Pdi | 55.3 (146/264) | 3.07 (49.3 to 61.3) |
SE, standard error of the mean; CI, confidence interval; Pdi, transdiaphragmatic pressure.
The combination of Sniff Pdi and Twitch Pdi diagnosed 55.3% of patients as having diaphragm weakness. The two tests combined reduced the diagnosis of diaphragm weakness by 18.9% compared with Sniff Pdi alone and 18.0% compared with Twitch Pdi alone.