High-frequency oscillation and tracheal gas insufflation in patients with severe acute respiratory distress syndrome and traumatic brain injury: an interventional physiological study

Table 3 Shunt fraction, peripheral perfusion indices, and hemodynamics

Ventilatory strategy	Shunt fraction	ScvO₂ (%)	Heart rate (beats/min)	MAP (mm Hg)
Pre HFO-TGI CMV	0.49 ± 0.09	70.1 ± 6.2	95 ± 24	92 ± 12
HFO-TGI (4 hours)	0.31 ± 0.09*	74.0 ± 3.9 *,§	92 ± 23	94 ± 13
HFO-TGI (8 hours)	0.29 ± 0.06*	74.6 ± 4.1 *,§	92 ± 23	93 ± 14
HFO-TGI (12 hours)	0.29 ± 0.06*	75.0 ± 4.1 *,§	92 ± 22	90 ± 15
Post HFO-TGI CMV	0.33 ± 0.14	70.5 ± 6.2	92 ± 22	90 ± 14
Ventilatory strategy	Cardiac Index (L/min/m ² BSA)	DO ₂ Index (ml/min/m ² BSA)	Arterial blood lactate (mM)	CVP (mm Hg)
Pre HFO-TGI CMV	4.8 ± 1.3	510 ± 119	1.72 ± 0.70	12 ± 3.4
HFO-TGI (4 hours)	4.7 ± 1.1	541 ± 119 §	1.82 ± 0.68	12 ± 3.0
HFO-TGI (8 hours)	4.8 ± 1.1	553 ± 114 *,§	1.85 ± 0.68	12 ± 2.9
HFO-TGI (12 hours)	4.7 ± 1.2	551 ± 119 *,§	1.82 ± 0.69	12 ± 2.8
Post HFO-TGI CMV	4.5 ± 1.1	513 ± 106	1.81 ± 0.74	11.5 ± 3.3

Values are mean ± SD. CMV, conventional mechanical ventilation; HFO, high-frequency oscillation; TGI, tracheal gas insufflation; pre-HFO-TGI CMV, corresponds to either the baseline CMV period of study day 1, or the 60-minute period that followed the 11-hour period of post-HFO-TGI CMV of the preceding study day (see also Figure 1 and corresponding legend); ScvO₂, central venous O₂ saturation; MAP, mean arterial pressure; BSA, body surface area; DO₂, peripheral O₂ delivery; CVP, central venous pressure.
* P < 0.01 versus pre-HFO-TGI CMV
^§ P < 0.05 versus post-HFO-TGI CMV

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