Intensive Care Medicine Experimental

Table 2 Six methods to determine the expiratory time constant (τ) in pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV)

From: Six methods to determine expiratory time constants in mechanically ventilated patients: a prospective observational physiology study

	PCV	VCV	p
Measured τ₁ (s)	0.59 (0.57–0.62)	0.60 (0.58–0.63)	0.45
Calculated τ (s)	0.64 (0.61–0.67)	0.66 (0.63–069)	0.17
Aerts τ (s)	0.57 (0.54–0.59)	0.58 (0.55–0.61)	0.37
Brunner τ (s)	0.64 (0.61–0.67)	0.66 (0.63–0.69)	0.17
Guttmann τ (s)	0.64 (0.61–0.68)	0.65 (0.62–0.69)	0.28
Lourens τ (s)	0.61 (0.58–0.64)	0.63 (0.60–0.66)	0.23

Values are shown in seconds as means with their corresponding 95% confidence intervals. Student’s t test was used to compare mean τ between PCV and VCV within each method of τ determination

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