Fig 1.
Illustration of methodology depicting invasive and non-invasive monitoring.
Table 1.
Lamb characteristics and hemodynamic parameters.
Table 2.
Arterial blood gas analysis.
Fig 2.
Arterial blood pressures during study period.
There is no difference in mean systolic blood pressures (A) and mean diastolic blood pressures (B) between lambs that achieve return of spontaneous circulation (ROSC) and those with no ROSC. Epinephrine did not statistically increase blood pressures in either group. Data are mean ± SEM bars.
Fig 3.
Mean left pulmonary artery flow.
There is no appreciable increase in flow following initiation of chest compressions or after epinephrine administration. Data are mean ± SEM bars.
Fig 4.
Mean left carotid artery flow.
There is only a modest increase in flow following initiation of chest compressions with no further increase after epinephrine use. Data are mean ± SEM bars.
Fig 5.
Maximum flow increases with initiation of chest compressions in lambs with ROSC and no ROSC. Reversal of flow occurs in diastole (minimum flow) at baseline (in utero), and remains retrograde during the relaxation phase of chest compressions in lambs of both groups. Flow becomes exclusively anterograde upon ROSC and cessation of chest compressions. Data are mean ± SEM bars.
Fig 6.
Maximum left carotid flow increases with initiation of chest compressions in lambs with ROSC and no ROSC. During the relaxation phase of chest compressions (minimum flow), retrograde flow is observed in lambs of both groups. Flow becomes exclusively anterograde upon ROSC and cessation of chest compressions. Data are mean ± SEM bars.
Fig 7.
Comparison of arterial blood gas analysis between groups during resuscitation.
(A) PaO2, (B) PaCO2, (C) pH, (D) Lactate. Gas sample “0” depicts “arrest gas.” Data are mean ± SEM bars. The number of lambs in the ROSC group drops with each successful ROSC (at “0” n = 18, at “1” n = 17, at “2” n = 8, at “3” n = 4, at “4” n = 2, at “6” n = 1).
Fig 8.
Comparison of arterial blood gas analysis following ROSC.
(A) PaO2; the secondary y-axis represents FIO2, (B) PaCO2, (C) pH, (D) Lactate. Data are mean ± SEM bars.
Fig 9.
Cerebral rSO2, preductal SpO2, SaO2 and SvO2 during study period in lambs with ROSC.
Pulse oximetry and NIRS are not reliable during resuscitation as shown by a discrepancy between SaO2 and SpO2, and SvO2 and cerebral rSO2 during chest compressions as well as in the first few minutes into ROSC. Data are mean ± SEM bars. * P <0.05 SvO2 vs. SpO2; † P <0.05 SvO2 vs. cerebral rSO2.