Central Venous-to-Arterial CO₂ Gap Is a Useful Parameter in Monitoring Hypovolemia-Caused Altered Oxygen Balance: Animal Study

Table 2

Changes of oxygen balance.

		𝑇0	𝑇1	𝑇2	𝑇3	𝑇4	𝑇5
SaO2 (%)	HG	94 ± 6	95 ± 5	95 ± 2	96 ± 2	94 ± 3	94 ± 2
	SG	95 ± 5	94 ± 8	96 ± 5	94 ± 8	95 ± 5	94 ± 7
Hb (g/L)	HG	122 ± 9	129 ± 13	132 ± 7*	134 ± 7^*‡	137 ± 7^*‡	138 ± 8*
	SG	119 ± 10	115 ± 9	110 ± 6	108 ± 11	111 ± 9	102 ± 10
DO2I (mL/min/m^2)	HG	361 ± 39	302 ± 52^*‡	268 ± 47^*‡	258 ± 55*	269 ± 65*	284 ± 55*
	SG	365 ± 78	396 ± 88	346 ± 73	337 ± 67	324 ± 55	298 ± 36
VO2/DO2 (%)	HG	28 ± 5	31 ± 6^*‡	34 ± 7^*‡	39 ± 9^*‡	41 ± 9*	40 ± 10*
	SG	25 ± 4	25 ± 6	26 ± 7	29 ± 5	27 ± 6	30 ± 7
ScvO2 (%)	HG	74 ± 10	71 ± 10	67 ± 11^*‡	64 ± 14*	59 ± 13^*‡	57 ± 14*
	SG	77 ± 8	76 ± 10	76 ± 9	75 ± 11	73 ± 14	73 ± 12
CO2-gap (mmHg)	HG	4.3 ± 2.3	7.5 ± 3.3	7.1 ± 2.6*	8.3 ± 2.8*	7.3 ± 2.9*	10.1 ± 5.5^*#
	SG	4.1 ± 2.4	3.5 ± 1.9	4.5 ± 1.3	3.9 ± 2.9	4.6 ± 1.9	4.4 ± 1.9
Lactate (mmol/L)	HG	3.8 ± 1.4	3.9 ± 1.3	4.3 ± 0.9	4.7 ± 0.9^*‡	5.1 ± 1.2^*‡	5.3 ± 1.5*
	SG	3.8 ± 0.9	3.9 ± 1.2	4.2 ± 1.8	4.6 ± 2.1	4.7 ± 2.7	4.9 ± 3.2
VO2I (mL/min/m^2)	HG	98 ± 11	93 ± 16	88 ± 9	96 ± 7^‡	104 ± 10^‡	109 ± 16
	SG	88 ± 16	96 ± 6	85 ± 12	96 ± 8	85 ± 12	88 ± 14

SaO₂: arterial oxygen saturation; Hb: hemoglobin; DO₂: oxygen delivery; VO₂/DO₂: oxygen extraction ratio; ScvO₂: central venous oxygen saturation; CO₂ gap: venous-to-arterial carbon dioxide difference; VO₂: oxygen consumption. 𝑇₀: baseline measurement; 𝑇₁--𝑇₅: five intervals. *𝑝<.05 as compared to 𝑇₁; ^‡𝑝<.05 as compared to the previous value; RM ANOVA; ^#𝑝<.05 HG versus SG; Mann-Whitney 𝑈-test with Bonferroni correction.