A New Method for In Vivo Analysis of the Performances of a Heat and Moisture Exchanger (HME) in Mechanically Ventilated Patients

Table 2

Temperature (T) and absolute humidity (AH) values of Heat and Moisture Exchanger (HME) performance indicators; SD: standard deviation.

HME performance indicators		t0: mean	t1: mean	t2: mean	Differences over time (p)
		(SD)	(SD)	(SD)
LOAD	T (°C)	33.6	33.4	33.3	0.51
		(1.38)	(1.49)	(1.18)
	AH (mg/l)	36.9	36.4	36.2	0.18
		(2.66)	(2.83)	(2.26)
RETURN (efficacy)	T (°C)	31.5	31.1	31.0	0.67
		(1.54)	(1.34)	(1.29)
	AH (mg/l)	32.3	31.7	31.4	0.11
		(2.60)	(2.26)	(2.27)
YIELD (efficiency)	Thermal differential (°C)	2.2	2.2	2.3	0.81
		(0.55)	(0.54)	(0.76)
	AH yield	0.89	0.89	0.89	0.24
		(0.03)	(0.03)	(0.04)
INPUT	T (°C)	25.9	25.2	25.5	0.80
		(0.76)	(0.71)	(0.88)
	AH (mg/l)	1.2	1.3	1.2	0.11
		(0.70)	(0.52)	(0.56)
LOSS	T (°C)	26.0	25.3	25.5	0.59
		(0.76)	(0.72)	(0.89)
	AH (mg/l)	6.3	6.9	6.6	0.62
		(1.36)	(1.94)	(2.57)