Table 2.

Respiratory parameters, ventilatory settings, and adjunctive interventions during mechanical ventilation course

		Day 1	Day 3	Day 5	Day 7	Day 10	Day 14	Day 21
Oxygenation status
PaO2, mmHg	S	77.0 [66.4–89.0]	85.0 [76.5–106.5]	82.0 [73.1–103.8]	81.2 * [76.7–99.1]	85.5 * [77.3–91.0]	92.5 * [83.2–106.5]	78.5 [70.9–105.6]
	NS	75.0 [61.0–91.8]	81.0 [64.2–103.0]	78.0 [60.6–97.3]	77.0 [65.0–83.8]	72.4 [61.7–79.5]	69.0 [55.3–78.0]	80.8 [76.9–87.3]
FiO2, unit	S	0.60 * [0.50–0.75]	0.50 * [0.48–0.60]	0.60 * [0.50–0.60]	0.50 * [0.41–0.55]	0.40 * [0.35–0.50]	0.40 * [0.31–0.49]	0.40 * [0.30–0.40]
	NS	0.75 [0.60–0.90]	0.70 [0.60–0.80]	0.70 [0.60–0.90]	0.65 [0.58–0.80]	0.80 [0.60–1.00]	0.85 [0.60–1.00]	0.70 [0.70–0.74]
PaO2/FiO2, mmHg	S	136.6 * [106.7–160.8]	170.6 * [124.2–210.0]	150.0 * [124.7–213.0]	161.7 * [141.6–245.2]	221.0 * [170.5–246.3]	252.7 * [169.8–316.7]	240.0 * [159.2–409.2]
	NS	105.5 [76.2–141.7]	125.0 [83.1–153.7]	112.0 [80.3–161.3]	108.9 [85.6–148.3]	92.2 [67.5–150.0]	79.0 [56.5–128.6]	116.2 [109.9–131.7]
«Optimum» PEEP, cmH2O	S	12.0 [10.0–12.0]	11.0 [10.0–14.0]	11.0 [10.0–14.0]	10.0 [10.0–12.0]	9.0 * [7.0–11.5]	8.5 [5.0–11.0]	7.0 [5.3–8.0]
	NS	11.0 [10.0–13.0]	12.0 [10.0–13.0]	10.0 [9.0–12.0]	10.0 [8.0–12.0]	10.0 [8.3–11.8]	10.0 [8.0–14.5]	9.5 [8.3–11.5]
Ventilation status
Tidal volume, ml/kg IBW	S	8.2 [7.3–8.8]	8.1 [7.0–8.8]	8.2 [7.0–8.9]	8.0 [7.2–9.6]	8.1 [7.1–10.6]	7.6 [6.3–8.8]	7.9 [7.4–10.8]
	NS	7.7 [7.1–8.2]	7.7 [7.2–8.2]	7.9 [7.1–8.4]	7.9 [7.1–8.8]	7.9 [7.3–8.7]	8.2 [7.1–9.0]	7.8 [6.7–9.1]
Total RR, min−1	S	20 [18-22]	20 [18-22]	20 [18-22] *	21 [17-23]	20 [17-22] *	23 [20-25]	22 [15-23]
	NS	21 [18-24]	22 [18-24]	23 [20-26]	22 [18-25]	23 [19-25]	23 [20-28]	23 [22-29]
Minute ventilation, l/min	S	10.0 [8.5–12.0]	10.0 [8.6–11.3]	9.9 * [8.1–11.5]	10.6 [8.2–13.7]	10.6 [9.1–12.0]	11.1 [8.0–12.8]	12.1 [8.5–15.7]
	NS	11.0 [9.0–13.2]	10.7 [9.0–13.0]	11.7 [10.5–14.0]	11.5 [9.6–13.2]	12.2 [9.5–14.8]	12.6 [10.0–13.6]	10.7 [9.1–12.0]
PaCO2, mmHg	S	47.0 [40.0–61.4]	52.1 [39.3–61.6]	42.0 [38.0–55.2]	40.0 [34.6–45.6]	39.5 * [35.5–44.6]	40.0 [36.4–43.8]	43.6 [37.4–48.0]
	NS	47.9 [40.3–56.5]	49.5 [42.3–58.1]	46.4 [40.7–54.2]	45.0 [40.5–55.5]	47.0 [39.5–58.5]	48.0 [37.4–58.0]	45.8 [37.6–73.8]
Ventilatory ratio	S	1.9 [1.6–2.6]	1.9 [1.7–2.6]	2.0 [1.5–2.2]	1.9 [1.5–2.1]	1.8 [1.5–2.1] *	1.7 [1.6–2.1] *	2.2 [1.3–2.4]
	NS	2.2 [1.7–2.7]	2.2 [1.7–2.7]	2.2 [1.8–2.7]	2.1 [1.7–2.8]	2.5 [1.9–3.2]	2.5 [1.9–3.2]	2.7 [1.9–3.2]
VDalv/VT, %	S	0.39 [0.17–0.46]	0.38 [0.28–0.50]	0.33 [0.24–0.41]	0.24 * [0.19–0.31]	0.26 * [0.20–0.33]	0.30 [0.25–0.39]	0.30 [0.21–0.44]
	NS	0.36 [0.27–0.46]	0.38 [0.30–0.48]	0.37 [0.24–0.45]	0.37 [0.25–0.45]	0.40 [0.29–0.51]	0.29 [0.22–0.41]	0.31 [0.15–0.52]
Respiratory mechanics
CRS, ml/cmH2O	S	38.4 [30.6–45.6]	37.0 [28.7–38.3]	39.8 [31.0–49.0]	42.2 * [29.4–49.0]	38.8 [28.2–45.3]	32.3 [25.3–46.3]	31.0 [25.0–43.0]
	NS	34.5 [25.0–42.3]	36.1 [26.2–42.3]	32.5 [25.0–41.5]	32.0 [24.5–41.8]	30.0 [26.0–37.3]	28.0 [20.7–43.5]	28.3 [15.0–39.0]
Plateau pressure, cmH2O	S	25.0 [23.5–27.5]	25.0 [24.0–30.0]	24.0 * [22.5–27.5]	23.0 * [22.0–25.0]	23.0 * [20.3–25.5]	22.5 * [19.5–27.3]	19.0 [15.0–19.0]
	NS	27.0 [24.0–31.0]	27.0 [24.0–30.0]	28.0 [24.0–31.5]	27.0 [24.0–31.0]	26.5 [24.0–30.8]	29.0 [24.5–36.5]	28.0 [22.3–34.5]
Driving pressure, cmH2O	S	13.5 [11.0–15.0]	14.0 [12.5–15.0]	13.0 * [10.5–15.0]	12.5 * [10.3–14.8]	13.5 * [11.0–15.8]	16.0 [11.5–17.5]	16.5 [13.0–22.3]
	NS	15.0 [12.0–20.0]	14.5 [12.0–19.0]	16.0 [13.0–20.0]	17.0 [13.5–20.5]	17.5 [15.0–20.0]	17.0 [13.0–27.5]	18.0 [11.8–25.8]
Resistance, mbar/l/s	S	10.0 [7.5–13.0]	10.0 [8.0–12.0]	10.5 [8.3–12.0]	8.5 [6.3–10.0]	9.5 [7.3–11.0]	10.5 [8.0–12.3]	11.0 [7.8–12.8]
	NS	9.0 [6.0–12.0]	9.0 [7.0–12.0]	8.0 [7.0–11.0]	8.0 [7.0–10.0]	8.5 [7.3–12.0]	10.0 [7.5–12.5]	8.0 [6.3–12.0]
Adjunctive respiratory interventions
Neuromuscular blockade, n (%)	S	13 (76.5)	9 (52.9) *	6 (35.3) *	3(18.8) *	1 (6.3) *	1 (6.7) *	1 (14.3)
	NS	87 (87.9)	83 (84.7)	59 (80.8)	35 (71.4)	28 (87.5)	18 (85.7)	1 (25.0)
Prone position, n (%)	S	7 (41.2)	6 (35.3)	5 (29.4)	4 (25.0)	0 (0)	0 (0) *	0 (0)
	NS	49 (49.5)	35 (35.4)	22 (30.1)	8 (16.3)	3 (9.4)	5 (23.8)	1 (25.0)
Lateral position, n (%)	S	6 (35.3)	4 (23.5)	1 (5.9)	0 (0)	1 (6.3)	0 (0)	0 (0)
	NS	19 (19.2)	20 (20.2)	14 (19.2)	14 (28.6)	8 (25.0)	5 (23.8)	0 (0)
Assessment of ventilator-associated respiratory infection
Modified CPIS, points	S	1 [1,2]	1 [1,2] *	2 [2] *	2 [2,3] *	5 [5]	5 [4,5]	5 [4,5]
	NS	1 [1,2]	2 [1,2]	2 [2,3]	3 [3,4]	5 [5,6]	5 [5,6]	6 [5,6]
Organ support
ECMO, n (%)	All	0	0	0	0	0	0	0
RRT, n (%)	S	1 (5.9)	1 (5.9)	0	0	1 (6.3)	0 *	0
	NS	2 (2.0)	3 (3.1)	4 (5.5)	7 (14.3)	5 (16.1)	5 (23.8)	0
NE, n (%)	S	0	0 *	1 (5.9)*	1 (6.3)*	2(12.5)*	1 (7.1) *	0
	NS	19 (19.2)	27 (27.8)	32 (43.8)	21 (42.9)	18 (56.3)	14 (66.7)	2 (50.0)

Data presented as medians [interquartile range] or n (%) where appropriate. Differences between groups Mann–Whitney U-test, Chi-square or Fisher exact test where appropriate. Abbreviations:S Survivors; NS Non-Survivors; PaO₂ arterial oxygen partial pressure; FiO₂ fraction of inspiratory oxygen; PEEP positive end-expiratory pressure; IBW ideal body weight; RR respiratory rate; PaCO₂ arterial carbon dioxide partial pressure; VDalv/VT; alveolar dead space to tidal volume ratio; C_RS compliance of the respiratory system; CPIS Clinical Pulmonary Infection Score; ECMO extracorporeal membrane oxygenation; RRT renal replacement therapy; NE norepinephrine

^*p-value < 0.05, comparison between survivors and non-survivors