Respiratory Variations in Pulse Pressure Reflect Central Hypovolemia during Noninvasive Positive Pressure Ventilation

Table 1

Dynamic variables and hemodynamic data during spontaneous breathing and noninvasive positive pressure ventilation.

LBNP-level	Subjects completing the LBNP-level (𝑛)		ΔPP (%)		ΔPOP (%)		PVI (%)		PI (%)
	SB	NPPV	SB	NPPV	SB	NPPV	SB	NPPV	SB	NPPV
Baseline	14	12	7.4±3.1	7.1±2.4	12.4±5.4	13.5±10.0	18.5±6.9	18.4±10.0	2.8±2.1	3.2±2.0
20	14	12	7.6±2.5	7.1±1.9	12.7±6.1	14.0±7.5	18.8±8.0	17.8±11.6	2.4±1.9	2.5±1.4
40	13	10	8.3±8.0	9.8±4.4	13.4±8.0	14.4±6.7	18.6±7.2	20.1±10.1	2.2±1.6	2.7±1.4
60	12	10	9.3±3.8	12.1±5.2	12.2±4.1	14.4±6.2	21.1±8.3	22.1±9.9	2.3±1.4	2.5±1.1
80	11	9	12.6±7.1	15.7±6.0	16.6±5.5	18.4±6.6	22.5±8.5	26.9±10.4	2.1±1.2	2.1±1.3
LBNP-level	Subjects completing the LBNP-level (𝑛)		SV (mL)		HR (beats/min)		MAP (mm Hg)		PP (mm Hg)
	SB	NPPV	SB	NPPV	SB	NPPV	SB	NPPV	SB	NPPV
Baseline	14	12	80±13	79±12	59±8	57±6	78±11	78±17	58±12	62±9
20	14	12	73±14	67±14	58±8	59±8	76±11	75±18	60±14	60±17
40	13	10	60±13	53±15	64±9	67±11	77±13	76±20	57±14	55±17
60	12	10	50±13	43±11	73±11	78±14	77±12	77±19	51±11	52±16
80	11	9	35±12	32±8	89±17	93±20	77±14	72±23	45±9	45±19

Data are mean ± SD. LBNP: lower body negative pressure; SB: spontaneous breathing; NPPV: noninvasive positive pressure ventilation; ΔPP: pulse pressure variation; ΔPOP: photoplethysmographic waveform variation; PVI: pleth variability index; PI: perfusion index; HR: heart rate; SV: stroke volume; MAP: mean arterial pressure; PP: pulse pressure.