Table 3.
Crude hemodynamic measurements during different time periods and adjusted change in estimate with hyperoxic ventilation
| Hemodynamic variables | T1 | T2 | T3 | Hyperoxia vs. normoxia | P value |
|---|---|---|---|---|---|
| Pre | Hyperoxia | Post | Adjusted change in estimate (95% CI) | ||
| Central circulatory variablesa | |||||
| MAP (mmHg) | 77 (11) | 85 (11)*** | 78 (11) | 6.76 (3.88; 9.63) | <0.0001 |
| CVP (mmHg) | 9.1 (1.7) | 9.6 (1.7) | 9.3 (1.6) | 0.35 (0.11; 0.60) | 0.01 |
| HR (beats min−1) | 84 (14) | 82 (14) | 83 (15) | −0.55 (−3.05; 2.06) | 0.68 |
| Calculated variables | |||||
| CO Modelflow (L min−1)b | 5.12 (1.04) | 4.97 (1.13) | 4.98 (1.18) | −0.08 (−0.27; 0.11) | 0.41 |
| SVV (%)b | 13.6 (9.3) | 13.2 (6.9) | 15.3 (7.4) | −1.76 (−3.38; −0.03) | 0.05 |
| PPV (%)b | 15.6 (10.3) | 15.1 (7.6) | 16.6 (4.9) | −1.30 (−2.99; 0.49) | 0.16 |
| CO LiDCOplus (L min−1)c | 4.80 (1.10) | 4.62 (1.10) | 4.79 (1.27) | −0.12 (−0.40; 0.08) | 0.21 |
| Derived parametersd | |||||
| R sys (mmHg min L−1) | 13.4 (4.9) | 15.3 (5.9)*** | 13.6 (5.1) | 1.82 (0.96; 2.67) | <0.001 |
| P vr (mmHg) | 11.7 (3.3) | 13.5 (3.5)* | 12.1 (2.8) | 1.47 (0.61; 2.37) | <0.01 |
| R vr (mmHg min L−1) | 2.4 (0.8) | 2.8 (1.0)** | 2.5 (0.8) | 0.39 (0.21; 0.58) | <0.001 |
| Slopevrc (L min−1 mmHg−1) | −0.46 (0.16) | −0.38 (0.13)** | −0.44 (0.15) | 0.07 (0.03; 0.10) | <0.001 |
| P msf (mmHg) | 20.8 (3.5) | 23.1 (4.0)* | 21.4 (2.9) | 1.90 (0.95; 2.93) | <0.001 |
| R vo (mmHg min L−1) | 7.9 (3.2) | 7.9 (4.3) | 7.7 (1.9) | −0.09 (−1.17; 1.03) | 0.87 |
| Slopevoc (L min−1 mmHg−1) | 0.13 (0.05) | 0.15 (0.11) | 0.14 (0.04) | 0.01 (−0.03; 0.05) | 0.62 |
| P cc (mmHg) | 38.8 (9.8) | 47.9 (15.1)* | 40.9 (8.9) | 8.55 (4.13; 12.68) | <0.001 |
| Cerebral blood flowe | |||||
| BFVmca (cm s−1) | 34.6 (10.6) | 32.3 (10.3) | 33.6 (11.5) | −1.42 (−3.80; 1.01) | 0.26 |
| Pulsatility index | 0.95 | 0.96 | 1.0 | −0.03 (−0.07; 0.01) | 0.17 |
| Resistance index | 0.57 | 0.57 | 0.58 | 0 (−0.01; 0.01) | 0.66 |
| Microcirculationf | |||||
| RBC filling (%) | 72.3 (4.4) | 71.1 (5.0) | 72.9 (5.1) | −1.87 (−3.29; −0.34) | 0.02 |
| PBR (µm) | 2.1 (0.2) | 2.2 (0.2) | 2.1 (0.2) | 0.05 (−0.03; 0.12) | 0.21 |
| TVD (mm/mm2) | 12.2 (3.5) | 12.7 (3.5) | 12.0 (3.4) | 0.35 (−0.96; 2.08) | 0.66 |
| PVD (mm/mm2) | 12.0 (3.7) | 12.1 (2.9) | 12.0 (3.1) | −0.03 (−1.50; 1.70) | 0.97 |
| VVD (µm/mm2) | 712 (117) | 672 (130) | 699 (93) | −37.29 (−80.97; 8.01) | 0.11 |
| De Backer Score (n/mm) | 14.2 (1.2) | 15.1 (1.6) | 14.4 (1.6) | 0.86 (0.23; 1.51) | 0.01 |
| PV (%) | 99.6 (1.3) | 93.2 (8.3)* | 97.4 (6.1) | −4.72 (−7.64; −2.00) | <0.01 |
| 100 (IQR 99–100) | 98 (IQR 85–100) | 100 (IQR 99–100) | – | – | |
| Heterogeneity index (%) | 13 [9–14] | 22 [21–23]*** | 21 [15–21]*** | – | – |
Change in estimate (95% CI) with intervention (hyperoxia) in reference to normoxia periods from linear mixed model adjusted for age, temperature, Hb, PaCO2, norepinephrine dose and propofol dose. P value calculated using t tests with Satterthwaite approximations to degrees of freedom
Data are means (SD). For PV (%), medians (interquartile range) are provided
MAP mean arterial pressure, CVP central venous pressure, HR heart rate, CO cardiac output, SVV stroke volume variation, PPV pulse pressure variation, R sys resistance of the systemic circulation, P vr pressure difference between P msf and P cv, R vr resistance for venous return, Slope vrc slope of venous return curve, P msf mean systemic filling pressure, R vo resistance for ventricular output, Slope voc slope of ventricular output curve, P cc critical closing pressure, BFV mca blood flow velocity in middle cerebral artery, RBC red blood cell, PBR perfused boundary region, TVD total vascular density, PVD perfused vascular density, VVD valid vascular density, PV perfused vessels
* P < 0.01; ** P < 0.001; *** P < 0.0001 for paired comparison between indicated outcome and baseline (T1)
aDirectly measured from radial artery and central venous catheters
bCalculated beat-to-beat by pulse contour analysis from Modelflow and averaged over indicated time period
cCalculated by pulse contour analysis from LiDCOplus 15 min after starting the exposure at indicated time period
dSecondarily derived from Modelflow calculated variables
eDirectly measured using transcranial Doppler on middle cerebral artery
fCalculated from sublingual sidestream dark field imaging analyses