Introduction:
Transcutaneous CO
2
(tcPCO
2
)
and arterial CO
2
(artPCO
2
) become decoupled during shock.
Aim:
To test the hypotheses the gradient between tcPCO
2
and artPCO
2
(tc-artPCO
2
)
can be an early, sensitive measure to detect inadequate tissue perfusion
in a pig model of hemorrhage shock.
Methods:
Six female pigs were used. A transcutaneous monitor was attached to the ear for measuring transcutaneous O
2
(tcPO
2
) and tcPCO
2
. Pulmonary artery catheter and the pulse index continuous cardiac output (PiCCO) were instrumented for monitoring a variety of hemodynamic parameters. To induce massive hemorrhagic shock, blood was withdrawn stepwisely. Then, animals were resuscitated in stages with transfusions of the stored blood. The parameters were measured at the timings of 10, 20, and 30 ml/kg of blood withdrawals and the completions of 10, 20, and 30 ml/kg of blood transfusion
.
Levels of systemic oxygen delivery (DO
2
) were also calculated at all measurement points.
Results:
Hemorrhage and blood transfusion impacted hemodynamic and laboratory data, such as cardiac output (CO), stroke volume, MAP, heart rate, pulmonary artery wedge pressure, global end-diastolic volume, hemoglobin, and arterial lactate. The tc-artPCO
2
markedly increased as CO decreased (
Figure A
). The critical level of DO
2
(DO
2crit
) was defined as 11.72 ml/kg/min according to tcPO
2
(a threshold as 30 mmHg). There was significant correlation between tc-artPCO
2
and DO
2
(r = -0.83, P<.0001). ROC analyses revealed that the AUCs to predict DO
2crit
for tc-artPCO
2
, shock index (SI), and lactate were 0.94 (95% CI, 0.87-1.00), 0.78 (0.63-0.93), and 0.65 (0.47-0.82), respectively. The AUC for tc-artPCO
2
was greater with respect to the prediction of DO
2crit
than for SI (P<.05) (
Figure B
).
Conclusions:
The tc-artPCO
2
strongly correlated with CO and DO
2
during hemorrhage shock and resuscitation. The less-invasive tc-artPCO
2
monitoring can sensitively detect systemic inadequate O2 supply in hemorrhagic shock.
Single Versus Double Anatomic Site Intraosseous Blood Transfusion in a Swine Model of Hemorrhagic Shock
