The following is a summary of “Serial assessments of cardiac output and mixed venous oxygen saturation in comatose patients after out-of-hospital cardiac arrest,” published in the October 2023 issue of Critical Care by Grand et al.
Researchers started a retrospective study to assess the association of cardiac index (CI) and venous oxygen saturation (SvO2) with outcomes in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA).
They conducted a “BOX” trial involving 789 patients, with 565 (77%) participants partaking in the hemodynamic substudy (mean age of 62 with a standard deviation of 13 years, comprising 81% males). Soon after ICU admission, they placed pulmonary artery catheters. CI and SvO2 were continuously measured in the ICU until patients regained consciousness or died. All-cause mortality and renal replacement therapy within one year
The results showed the initial CI at a median of 1.7 (1.4–2.1) l/min/m2 and the initial mixed SvO2 at a median of 67 (61–73) %. In 39% of cases, CI was below the median when SvO2 was above the median, while 11% showed low SvO2 with CI below the median. Analysis suggested SvO2 <55% correlated with poor outcomes. In multivariable analysis, low CI at admission wasn’t significantly linked to mortality (P=0.14). SvO2 displayed a significant inverse association with mortality (hazard ratio adjusted: 0.91 [0.84–0.98] per 5% increase in SvO2, P=0.01). Moreover, SvO2 exhibited a significant inverse association with renal failure after adjusting for confounders ( OR adjusted: 0.73 [0.62–0.86] per 5% increase in SvO2, P=0.001). The combination of lower CI and lower SvO2 was associated with a higher risk of mortality (hazard ratio adjusted: 1.54 [1.06–2.23]) and renal failure ( OR : 5.87 [2.34–14.73]).
They concluded that low SvO2 and CI after OHCA were associated with increased mortality and renal failure.