The effects of nifedipine on respiratory mechanics investigated by theend-inflation occlusion method in the rat

Figures & data

Figure 1. Example of tracing recorded upon constant flow inflation arrest. The maximum pressure achieved at end inflation (Pdyn,max), the pressure drop due to frictional forces in the airway (Pmin,rs) and the overall resistive pressure drop (Pmax,rs), including Pmin,rs and the nearly exponential pressure dissipation due to viscoelasticity (Pvisc,rs), are shown. P1: pressure value immediately after flow arrest, Pel,rs elastic static pressure.

Table 1. Mean values (±SE, n = 8) of respiratory mechanics parameters as measured before (t0) and 5 (t1), 10 (t2) and 20 (t3) min after nifedipine intraperitoneal administration (5 mg/kg).

	t0	t1	t2	t3
Est,rs (cmH2O/ml)	1.79 ± 0.12	1.36 ± 0.08	1.54 ± 0.13	1.59 ± 0.11
		p < 0.05	p = 0.09	p = 0.09
Rmax,rs (cmH2O/ml s^−1)	0.41 ± 0.05	0.52 ± 0.11	0.39 ± 0.04	0.41 ± 0.03
		n.s.	n.s.	n.s.
Rvisc,rs (cmH2O/ml s^−1)	0.26 ± 0.035	0.39 ± 0.1	0.28 ± 0.02	0.31 ± 0.02
		n.s.	n.s.	n.s.
Rmin,rs (cmH2O/ml s^−1)	0.15 ± 0.025	0.13 ± 0.025	0.11 ± 0.016	0.1 ± 0.014
		n.s.	p < 0.05	p = 0.06
Heart rate (beats/min)	515 ± 29	445 ± 22	404 ± 23	356 ± 24
		p < 0.01	p < 0.01	p < 0.01

Est,rs: respiratory system elastance, Rmax,rs, Rvisc,rs, Rmin,rs: respiratory system total, visco-elastic, and ohmic resistances. Statistical indexes are also reported.