Table 5.

Response to treatment over time: covariates effect estimates on tidal volumes and rapid shallow breathing index and standard errors obtained from GEE.

	Estimate	Standard error	z value	P value
Tidal volumes (mL) at Day 1
One-day acupressure × 0.5 hrs	48.63	23.20	2.10	0.036*
Two-day acupressure × 1.0 hrs	32.32	14.68	2.20	0.028*
Two-day acupressure × 3.5 hrs	39.71	19.45	2.04	0.041*
Tidal volumes (mL) at Day 2
Two-day acupressure × 24.17 hrs	40.10	15.16	2.64	0.008*
Two-day acupressure × 24.5 hrs	43.35	17.63	2.46	0.014*
Two-day acupressure × 25.0 hrs	38.26	19.31	1.98	0.048*
The rapid shallow breathing index (breaths/min/L) at Day 1
One-day acupressure × right after	−10.28	3.20	−3.21	0.001*
Two-day acupressure × right after	−12.28	4.07	−3.01	0.003*
One-day acupressure × 0.5 hrs	−15.77	6.07	−2.60	0.009*
Two-day acupressure × 0.5 hrs	−13.72	6.27	−2.19	0.029*
One-day acupressure × 1.0 hrs	−9.41	4.33	−2.18	0.030*
Two-day acupressure × 1.0 hrs	−11.85	5.09	−2.33	0.020*
One-day acupressure × 2.0 hrs	−10.03	4.86	−2.06	0.039*
The rapid shallow breathing index (breaths/min/L) at Day 2
Two-day acupressure × 24.17 hrs	−11.92	3.66	−3.26	0.001*

For treatment, the category “control group” was taken as the reference, and either one-day acupressure or two-day acupressure was used as a representative variable for each of the two groups; for time, the category “baseline” at Day 1 was taken as the reference, right after, 0.5 hrs, 1 hr, 1.5 hrs, 2 hrs, 2.5 hrs, 3 hrs, 3.5 hrs, and 4 hrs were representative variables, the category “24 hrs” at Day 2 was taken as the reference, and 24.17 hrs, 24.5 hrs, 25 hrs, 25.5 hrs, 26 hrs, 26.5 hrs, 27 hrs, 27.5 hrs, and 28 hrs were representative variables. For setting, the category “RCC” was taken as the reference. In addition to treatment, time, setting, BMI, GCS, smoking amount, gender, and baseline values were forced into the model to perform GEE. *P < 0.05 compared to controls for the treatment × time interaction.