. 2001 Mar 15;531(Pt 3):677–691. doi: 10.1111/j.1469-7793.2001.0677h.x

Table 2.

Groupmean results inrandomised steady-stateconditions

	Peak phasic GG EMG (% Max)	Tonic GG EMG (% Max)	Peak negative P_epi (cmH₂O)	Peak flow (l s⁻¹)	resistance (cmH₂o (l s⁻¹)⁻¹)
Experiment A
1. Eucapnia, spontaneous breathing	6.12 ± 1.20	3.92 ± 0.83	−2.18 ± 0.14	0.52 ± 0.03	(pharyngeal) 0.50 ± 0.19
2. Eucapnia, medium neg. press. vent. short T_tot	9.75 ± 2.37^*	4.52 ± 0.89	−6.14 ± 0.26^*	0.89 ± 0.06^*	0.97 ± 0.27
3. Hypocapnia, medium neg. press. vent. short T_tot	9.66 ± 2.14^*	4.69 ± 0.85	−5.81 ± 0.30^*	0.88 ± 0.07^*	0.92 ± 0.33
4. Eucapnia, high neg. press. vent. short T_tot	11.97 ± 2.75^*^†	4.80 ± 0.88	−10.45 ± 0.28^*^†	1.13 ± 0.09^*^†	0.39 ± 0.14
5. Hypocapnia, high neg. press. vent. short T_tot	11.96 ± 2.43^*^†	5.47 ± 1.02^*	−10.27 ± 0.31^*^†	1.17 ± 0.09^*^†	0.65 ± 0.27
6. Hypocapnia, medium neg. press. vent. long T_tot	8.21 ± 2.56	3.16 ± 0.70	−6.20 ± 0.41^*	1.07 ± 0.05^*	0.19 ± 0.08
7. Hypocapnia, high neg. press. vent. long T_tot	11.24 ± 3.18	7.23 ± 2.52	−9.77 ± 0.52^*	1.24 ± 0.17^*	0.48 ± 0.27
Experiment B
8. Eucapnia, spontaneous breathing	8.86 ± 2.19	5.31 ± 1.27	−1.86 ± 0.16	0.51 ± 0.04	(supraglottic) 3.30 ± 0.41
9. Hypercapnia, spontaneous breathing	10.34 ± 2.05	5.72 ± 1.06	−3.27 ± 0.44^§	0.67 ± 0.04^§	3.78 ± 0.22
10. Eucapnia, medium neg. press. vent.	12.67 ± 3.36^‡	5.15 ± 1.43	−6.31 ± 0.27^‡	0.97 ± 0.10^‡	3.46 ± 0.39
11. Hypercapnia, medium neg. press. vent.	15.69 ± 4.02^‡	6.40 ± 1.62	−7.13 ± 0.44^‡^§	0.95 ± 0.04^‡	3.75 ± 0.33

Values are means ±s.e.m.; n = 11, 5, 8 and 7 for conditions1–5, 6–7, 8–10 and 11,respectively. Resistance, pharyngeal in experiment A and supraglottic in experiment B, was measuredat a constant inspiratory flow of 0.2 l s⁻¹ (seeMethods). Experiment A:

significant difference (P< 0.05) vs. eucapnia spontaneous breathing

^†

significant difference amongconditions with different peak negative P_epi at equivalent P_et,co₂ (comparisons 2vs.4, and 3 vs. 5). Note:there were no statisticallysignificant effects on any of the variables of either altering P_et,co₂ (2 vs. 3, and 4 vs. 5) or respiratoryrate (3 vs. 6, and 5 vs. 7). Experiment B:

^‡

significant differences (P < 0.05) due to mode of ventilation (spontaneous breathing vs. negative pressure ventilation at equivalent P_et,co₂: i.e. 8 vs. 10, and 9 vs. 11)

^§

significant differences due to P_et,co₂ during similar modes ofventilation (8 vs. 9, and and 10 vs. 11).