Table 1.

Effects of Circuit Flushing and ASPIDS at increasing respiratory rate

RESPIRATORY RATE		MV, Lit.	VT, ml	Pplat, cmH2O	Cst, ml/cmH20	V'CO2 ml/min	PaCO2, kPa	pH	PaO2, kPa	HR, b/min	MAP, mmHg
RR20	Baseline	4.1 ± 0.6	208 ± 31	14 ± 2.6	20 ± 3	133 ± 10	5.3 ± 0.2	7.47 ± 0.04	12.3 ± 1.2	74 ± 20	84 ± 17
	After 30 minutes of Circuit Flushing	4.1 ± 0.6	208 ± 31	14 ± 3.5			4.7 ± 0.4 *	7.51 ± 0.04 *	12.6 ± 1.2	78 ± 20 **	83 ± 15
RR40	Baseline	4.9 ± 0.5	130 ± 13	13 ± 3.7	15 ± 4	142 ± 20	5.9 ± 0.4 #	7.43 ± 0.04	10.7 ± 0.9	79 ± 15	81 ± 12
	After 30 minutes of Circuit Flushing	4.9 ± 0.5	130 ± 13	14 ± 3.5 **			4.7 ± 0.3 **	7.51 ± 0.04 **	12 ± 1.5	81 ± 13	80 ± 9
	After 30 minutes of Circuit Flushing + ASPIDS	4.9 ± 0.5	130 ± 13	13 ± 3.6			3.9 ± 0.2 *	7.58 ± 0.05 **	12 ± 1.8	84 ± 11	79 ± 10
RR60	Baseline	5.9 ± 0.5	101 ± 9.5	13 ± 2.2	12 ± 2	136 ± 16	6.3 ± 0.4 #	7.40 ± 0.05	9.6 ± 1.3	84 ± 9	81 ± 9
	After 30 minutes of Circuit Flushing	5.9 ± 0.5	101 ± 9.5	14 ± 2			4.6 ± 0.6 **	7.51 ± 0.07 *	11.5 ± 2 *	91 ± 20	83 ± 9
	After 30 minutes of Circuit Flushing + ASPIDS	5.9 ± 0.5	101 ± 9.5	12 ± 2 **			3.7 ± 0.5 **	7.59 ± 0.07 **	11.2 ± 2.8	94 ± 22	79 ± 11

* P < 0.01; ** P < 0.001 (comparison were made to the preceding value). # P <0.05 (comparison between baseline at RR40 and 60 vs baseline at RR20, and between baseline at RR60 vs baseline at RR40). ASPIDS, aspiration of dead space; Cst, static compliance; HR, heart rate; MAP, mean arterial pressure; MV, minute ventilation; PaCO_2, carbon dioxide arterial partial pressure; PaO_2, oxygen arterial partial pressure; Pplat, plateau pressure; RR, respiratory rate; V_T, tidal volume; V'CO_2, carbon dioxide production.