Positive end-expiratory pressure in COVID-19 acute respiratory distress syndrome: the heterogeneous effects

Table 1 Respiratory mechanics and gas exchange within 5 and 15 cmH₂O of PEEP

Variables	PEEP 5 61 patients	PEEP 15 61 patients	p
Plateau pressure, cmH₂O	17 ± 3	28 ± 3	< *0.001*
Driving pressure, cmH₂O	12 ± 3	13 ± 3	0.071
Respiratory system elastance, cmH₂O/L	23 [19–27]	24 [21–31]	0.093
Lung elastance, cmH₂O/L	18 [15–22]	19 [17–25]	*0.049*
Chest wall elastance, cmH₂O/L	5 [3–6]	4 [3–6]	0.845
Lung stress, cmH₂O	13.1 ± 3.1	22.3 ± 4.0	< *0.001*
Mechanical power, J/min	16.7 ± 5.7	26.1 ± 6.4	< *0.001*
Mechanical Power_Compliance_rs, J/min/(mL/cmH₂O)	0.36 [0.27–0.50]	0.61 [0.51–0.77]	< *0.001*
PaO₂, mmHg	63 [55–76]	84 [74–99]	< *0.001*
PaO₂/FiO₂, mmHg	82 [66–138]	127 [90–184]	< *0.001*
Right-to-left shunt, %	47 ± 15	35 ± 12	< *0.001*
PvO₂, mmHg	42 ± 7	47 ± 7	< *0.001*
ScvO₂, %	74 ± 8	79 ± 6	< *0.001*
C_a-vO₂, mL	2.8 [2.3–3.2]	3.0 [2.4–3.4]	*0.024*
PaCO₂, mmHg	48 ± 9	50 ± 9	< *0.001*
Ventilatory ratio	1.66 ± 0.39	1.74 ± 0.37	*0.002*
Estimated physiological dead space	0.50 [0.43–0.58]	0.52 [0.42–0.60]	< *0.001*

Paired T-test or Wilcoxon–Mann–Whitney test for repeated measures were performed, as appropriate. Tidal volume and respiratory rate were unchanged between the two PEEP levels. C_a-vO₂: arterial–venous oxygen content difference; Compliance_rs: respiratory system compliance; ScvO₂ central oxygen venous saturation; PvO₂ mixed venous oxygen tension

ISSN: 1364-8535