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. 2010 May 10;588(Pt 13):2487–2501. doi: 10.1113/jphysiol.2009.186056

Table 3.

Physiological impact of acute inspiratory pressure unloading

Healthy control %Δ Heart failure %Δ P value
Pulmonary pressures
Wb −56.7 ± 12.6 −55.5 ± 12.0 0.95
Ppl mean insp −38.9 ± 7.0 −46.8 ± 6.5 0.15
∫Ppl,inspt −59.9 ± 13.0 −73.2 ± 7.5 0.41
∫Ppl,totalt −130.2 ± 36.2 −190 ± 27.8 0.24
Haemodynamics
Inline graphic −3.0 ± 6.1 17.1 ± 5.2 0.02
SV −5.6 ± 6.4 13.0 ± 5.0 0.03
HR 2.8 ± 0.8 3.7 ± 3.0 0.78
SBP 1.4 ± 2.1 −3.6 ± 1.7 0.10
DBP 0.5 ± 1.6 −0.8 ± 1.6 0.58
MAP 1.0 ± 1.9 −2.0 ± 1.6 0.26
LBF −2.4 ± 2.1 44.1 ± 5.9 <0.0001
Inline graphic 7.0 ± 7.7 25.4 ± 8.1 0.04
Inline graphic 1.1 ± 2.6 46.2 ± 5.7 <0.0001
LVR 3.7 ± 2.1 −32.7 ± 2.0 <0.0001
Blood gases
Inline graphic −0.3 ± 2.5 7.6 ± 1.9 0.03
Inline graphic −0.4 ± 2.8 −3.1 ± 2.0 0.45
Inline graphic 1.2 ± 0.8 −1.4 ± 1.1 0.08
Inline graphic −3.6 ± 1.4 −1.5 ± 2.0 0.42
Inline graphic −0.7 ± 1.8 −1.8 ± 2.1 0.69
Inline graphic −5.0 ± 1.9 −0.8 ± 3.1 0.28
a–v O2 diff 3.6 ± 1.1 −0.8 ± 1.3 0.03
Ventilation
Inline graphic −1.9 ± 6.1 18.3 ± 5.7 0.04
Inline graphic 23.0 ± 6.5 32.3 ± 7.5 0.36
VT 25.3 ± 7.0 29.0 ± 4.3 0.66
RR −0.3 ± 5.8 2.9 ± 4.9 0.68
TI 10.0 ± 8.2 −9.7 ± 8.6 0.98
TTOT −2.1 ± 8.0 −1.4 ± 6.0 0.74

Wb, work of breathing; Ppl, pleural pressure; insp, inspiratory; Inline graphic, cardiac output; SV, stroke volume; HR, heart rate; SBP, systolic blood pressure (direct arterial); DBP, diastolic blood pressure (direct arterial); MAP, mean arterial pressure (direct arterial); LBF, leg blood flow; Inline graphic, oxygen consumption; LVR, leg vascular resistance; Inline graphic, partial pressure of arterial oxygen; Inline graphic, partial pressure of arterial carbon dioxide; Inline graphic, arterial oxygen content; Inline graphic, partial pressure of venous oxygen; Inline graphic, partial pressure of venous carbon dioxide; Inline graphic, venous content of oxygen; a–v O2 diff, arterio-venous oxygen difference; Inline graphic, volume of oxygen consumption; Inline graphic, ventilation; VT, tidal volume; RR, respiratory rate; TI, inspiratory time; TTOT, total respiratory cycle time. Data are presented as mean ±s.e.m.