Supplemental methods: equations
From the data collected in each step calculated values were obtained by the following equations:
-
the membrane lung (ML) blood flow resistance (Res, mmHg/L/min):
Res (mmHg/L/min) =
P_in (mmhg) − P_out (mmhg)
BF (L/min)
where P_in was the blood circuitry pressure at ML blood inlet (Blood_IN) (mmHg), P_out was
the blood circuitry pressure at ML blood outlet (Blood_OUT) (mmHg), and BF was the blood
flow (L/min);
-
the oxygen content at Blood_IN (CinO2, mL/dL):
CinO2 (mL/dL) =
1.34 × Hb (g/dL) × SinO2 (%)
+ 0.0031 × p_inO2 (mmHg)
100
where Hb was the hemoglobin (g/dL), SinO2 was the O2 saturation at Blood_IN (%) and p_inO2
was the O2 partial pressure at Blood_IN (mmHg);
-
the oxygen content at Blood_OUT (CoutO2, mL/dL):
CoutO2 (mL/dL) =
1.34 × Hb (g/dL) × SoutO2 (%)
+ 0.0031 × p_outO2 (mmHg)
100
where Hb was the hemoglobin (g/dL), SoutO2 was the O2 saturation at Blood_OUT (%) and
p_outO2 was the O2 partial pressure at Blood_OUT (mmHg);
-
the ideal hemoglobin “capillary ML blood” saturation (SiO2, %):
SiO2 (%) = 100 − COHb (%) − MetHb (%)
where COHb is the average between carboxyhemoglobin at Blood_IN and Blood_OUT (%) and
MetHb is the average between methemoglobin at Blood_IN and Blood_OUT (%);
-
the ideal oxygen content of “capillary ML blood” (CiO2, mL/dL):
CiO2 (mL/dL) =
1.34 × Hb (g/dL) × SiO2 (%)
+ 0.0031 × 713
100
where Hb was the hemoglobin (g/dL), SiO2 was the ideal O2 hemoglobin ML saturation (%);
-
the ML BF shunt fraction (Qs/Qt, %):
Qs/Qt (%) =
-
CiO2 (mL/dL) − CoutO2 (mL/dL)
× 100
CiO2 (mL/dL) − CinO2 (mL/dL)
the ML oxygen uptake (VO2 , mL/min), according to the Fick equation:
VO2 (mL/dL) = (CoutO2 (mL/dL) − CinO2 (mL/dL)) × BF (L/min) × 10
-
the ML gas outlet mix carbon dioxide partial pressure (peCO2, mmHg)
peCO2 (mmHg) =
713 (mmHg) × [expCO2 ] (ppm)
1000000
where [expCO2] was the CO2 fractional concentration (ppm) measured by CO2 analyzer at the
ML gas outlet (Gas_OUT);
-
the ML dead space (Vd/Vt, %), according to the Bohr method:
Vd/Vt (%) =
p_outCO2 (mmHg) − peCO2 (mmHg)
× 100
p_outCO2 (mmHg)
where p_outCO2 was the CO2 pressure at Blood_OUT (mmHg);
-
the ML carbon dioxide removal (VCO2, mL/min) was calculated:
VCO2 (mL/min) =
-
GF(L/min) × [expCO2 ](ppm)
1000
the ML CO2 removal efficiency ratio (VCO2/CO2in, %) was computed as the ratio between
VCO2 and total CO2 content in the ML inlet blood sample:
VCO2 /CO2 in (%) =
VCO2 (mL/min)
22.41 × inCO2 (mMol/L) × BF(L/min)
where in CO2 was the total CO2 at Blood_IN calculated as follows:
inCO2 (mMol⁄L) = inHCO−
3 (mMol⁄L) + (0.03 × p_inCO2 (mmHg) )
where inHCO3- and p_inCO2were the bicarbonate ion concentration (mMol/L) and the CO2
partial pressure (mmHg) at Blood_IN, respectively.
Supplemental results: tables
Baseline
GF
Patient ML ML day
of use (L/min)
peCO2
After-RM
VCO2
VO2 (mL/min)
(mmHg)
(mL/min)
Vd/Vt (%)
peCO2
VCO2
(mmHg)
(mL/min)
Qs/Qt (%)
VO2 (mL/min)
Vd/Vt (%)
Qs/Qt (%)
1
1
2
5
22.7
159
167
49.2
8.3
24.7
173
158
31.1
7.4
1
1
3
4
19.1
107
168
61.9
7.6
24.5
137
156
45.1
8.0
1
1
8
7
15.4
151
146
60.3
10.7
17.5
172
144
48.9
11.0
1
1
9
6
15.8
133
131
54.5
14.0
19.7
166
132
36.1
11.5
1
1
13
4
18.9
106
103
52.8
23.1
19.8
111
99
49.7
18.8
2
2
1
3
36.4
153
137
8.2
6.0
33.5
141
141
5.6
4.5
2
2
4
4
21.3
120
140
40.9
5.0
20.6
116
146
29.4
6.4
2
3
8
6
17.5
147
150
52.8
5.4
21.2
179
155
27.2
5.1
2
4
2
4
18.1
101
103
47.4
3.8
24.2
136
104
18.2
3.0
3
5
8
7
11.3
111
187
71.7
11.5
17.9
176
207
50.5
9.8
4
6
19
9
13.2
166
137
63.8
10.8
14.0
177
138
58.1
7.4
5
7
2
5
24.4
171
217
52.1
10.5
33.6
235
205
21.2
8.8
5
8
3
7
21.2
208
223
48.0
9.2
24.2
238
214
32.9
8.7
5
9
2
6
21.2
179
145
51.9
7.2
25.5
215
158
23.6
2.4
5
9
4
5
25.8
181
174
44.9
7.3
28.6
201
184
23.5
4.1
5
10
3
6
23.0
194
169
43.1
7.2
27.4
230
183
21.8
4.4
5
11
5
5
24.2
169
137
45.7
5.0
30.4
213
139
20.8
3.9
6
12
6
2
23.2
65
152
47.5
8.0
36.1
101
158
12.5
4.5
7
13
1
4
33.3
187
152
9.3
5.9
32.2
180
159
6.8
4.8
7
13
4
6
19.4
163
165
49.7
9.4
22.5
189
178
29.5
6.3
Table S1. Results of membrane lung (ML) gas exchanges during all tests at Baseline and After-RM steps
Hemodynamics
p value
Baseline
After-RM
Heart Rate (bpm)
105 ± 12
102 ± 21
0.73
Systolic Arterial Pressure (mmHg)
118 ± 26
115 ± 22
0.31
Diastolic Arterial Pressure (mmHg)
62 ± 12
60 ± 12
0.46
Mean Arterial Pressure (mmHg)
79 ± 15
78 ± 12
0.47
Systolic Pulmonary Pressure (mmHg)
33 ± 6
31 ± 6
0.14
Diastolic Pulmonary Pressure (mmHg)
17 ± 3
16 ± 5
0.97
Mean Pulmonary Pressure (mmHg)
24 ± 3
22 ± 5
0.73
Wedge Pressure (mmHg)
12 ± 4
10 ± 5
0.10
Central Venous Pressure (mmHg)
9±4
8±3
0.34
Cardiac Output (L/min)
7.5 ± 1.3
7.2 ± 1.4
0.35
Internal Temperature (°C)
37.2 ± 0.3
37.2 ± 0.3
0.27
End Tidal CO2 (mmHg)
36 ± 3
34 ± 6
0.10
Pulse Oximeter Saturation (%)
97 ± 2
96 ± 3
0.37
Table S2. Hemodynamics at Baseline and After-RM steps. Data are reported as mean ±
standard deviations. No statistical significance was found.
Baseline
After-RM
1hr-RM
2hr-RM
4hr-RM
6hr-RM
ML gas transfer
VCO2 (mL/min)
VO2 (mL/min)
177 ± 12 A,B
210 ± 15 C
194 ± 16 D
188 ± 16 D,E
180 ± 16 A
171 ± 11 B
158 ± 16 A
168 ± 19 A,B
180 ± 19 B
174 ± 24 A,B
173 ± 21 A,B
164 ± 23 A,B
Circuitry Blood Gas Analyses
Blood_IN
7.410 ± 0.042 A
7.444 ± 0.041 B
7.467 ± 0.042 B
7.468 ± 0.045 B
7.447 ± 0.035 B
7.436 ± 0.023 A,B
pCO2 (mmHg)
55.2 ± 0.4 A
49.1 ± 4.8 B,C
45.7 ± 5.1 C
45.9 ± 4.7 B,C
48.3 ± 4.7 B,C
49.6 ± 4.3 B
HCO3- (mMol/L)
34.3 ± 4.9 A
33.2 ± 4.5 A,B
32.4 ± 4.5 B
32.6 ± 4.4 B
32.6 ± 4.0 B
32.5 ± 4.5 B
pO2 (mmHg)
45.9 ± 3.4 A
43.1 ± 3.9 A
41.6 ± 3.2 A
43.5 ± 4.3 A
43.3 ± 1.4 A
44.4 ± 2.9 A
HbO2 (%)
77.2 ± 3.2 A
76.4 ± 3.1 A
74.8 ± 2.2 A
75.7 ± 3.1 A
74.8 ± 3.1 A
76.6 ± 4.0 A
pH
Blood_OUT
7.487 ± 0.030 A
7.544 ± 0.032 A,B
7.555 ± 0.038 B
7.548 ± 0.029 B
7.543 ± 0.028 A,B
7.507 ± 0.021 A,B
pCO2 (mmHg)
42.9 ± 3.3 A
35.2 ± 2.7 B,C
33.2 ± 2.3 C
34.1 ± 2.8 B,C
36.3 ± 3.8 B,D
38.6 ± 4.0 D
HCO3- (mMol/L)
31.4 ± 4.6 A
29.8 ± 4.1 B
29.1 ± 3.7 B
29.2 ± 3.7 B
29.7 ± 3.9 B
30.0 ± 4.0 B
540.2 ± 21.2 B
588.7 ± 25.2 A
578.6 ± 21.1 A,B
569.4 ± 27.8 A,B
547.0 ± 32.5 A,B
539.5 ± 28.5 A,B
97.6 ± 0.2 A
97.6 ± 0.2 A
97.6 ± 0.2 A
97.6 ± 0.2 A
97.5 ± 0.3 A
97.5 ± 0.3 A
pH
pO2 (mmHg)
HbO2 (%)
Table S3. RM long-term evaluation: membrane lung (ML) gas transfer and circuitry blood gas analyses. Blood_IN and Blood_OUT are the
blood withdrawal at the ML inlet and ML outlet, respectively. Data are reported as mean ± standard deviations. Steps not connected by the same
letter are significantly different (p < 0.05).
Supplemental results: figure legends
Figure S1. Panel A: correlation between membrane lung (ML) dead space fraction (Vd/Vt, %) at
Baseline step and ML days of use. Panel B: correlation between Vd/Vt at After-RM step and ML
days of use.
Figure S2. Panel A: correlation between membrane lung (ML) shunt fraction (Qs/Qt, %) at
Baseline step and ML days of use. Panel B: correlation between Qs/Qt at After-RM and ML days of
use.
Figure S3. Panel A: correlation between membrane lung (ML) dead space fraction (Vd/Vt, %) and
ML shunt fraction (Qs/Qt, %) at Baseline step. Panel B: correlation between Vd/Vt and Qs/Qt at
After-RM step.