Mixed venous versus central venous oxygen saturation in patients undergoing on pump beating coronary artery bypass grafting

Abstract

Objective:To examine the validity of central venous oxygen saturation (ScvO2) as a numerical substitution of mixed venous oxygen saturation (SvO2) in adult patients undergoing normothermic on pump beating coronary artery bypass grafting (CABG).Materials and Methods:Prospective clinical observational study was done at King Khalid University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia. Thirty four adult patients scheduled for coronary artery surgery were included. Patients were monitored by a pulmonary artery catheter (PAC) as a part of our routine intraoperative monitoring. SvO2 and ScvO2 were simultaneously measured 15 minutes (T1) and 30 minutes (T2) after induction of anesthesia, 15 and 30 minutes after initiation of cardiopulmonary bypass (T3 and T4), and 15 and 30 minutes after admission to intensive care unit (T5 and T6).Results:ScvO2 showed higher reading than SvO2 all through our study. Our results showed perfect positive statistically significant correlation between SvO2 and ScvO2 at all data points. Individual mean of difference (MOD) between both the readings at study time showed MOD of 1.34 and 1.44 at T1 and T2 simultaneously. This MOD was statistically insignificant, but after on pump beating normothermic bypass was initiated; MOD was 5.2 and 4.4 at T3 and T4 with high statistical significance. In ICU, MOD continues to have high statistical significance, MOD was 6.3 at T5 and at T6 it was 4.6.Conclusions:In on pump beating CABG patients; ScvO2 and SvO2 are not interchangeable numerically. ScvO2 is useful in the meaning of trend; our data suggest that ScvO2 is equivalent to SvO2 , only in the course of clinical decisions as long as absolute values are not required.

Agreement between Central and Mixed Venous Oxygen Saturation Following Cardiac Surgery

“…In this study, the limits of agreement between SvO 2 and ScvO 2 were large (+15.8 % to -8.2 %), this comes in line with other studies involving patients after cardiac surgery [11][12][13][14][15]. Alshaer et al [8] examined the correlation during beating heart coronary surgery and concluded that SvO 2 and ScvO 2 are not interchangeable numerically but ScvO 2 can be useful if used as a trend. Soussi et al [9] concluded that central venous saturation can not be an alternative to mixed venous saturation during cardiopulmonary bypass.…”

“…The previous studies evaluating the relationship between ScvO 2 and SvO 2 showed a significant variation in results because of different study designs and clinical setup which included intensive care patients with either sepsis, heart failure, or shock [4][5][6][7]. Studies involving such relationship during and after cardiac surgery [8][9][10][11][12][13][14][15] also showed contradicting results, this controversy is generating confusion among clinicians and further work is needed to explore this area.…”

Use of the PiCCO system in critically ill patients with septic shock and acute respiratory distress syndrome: a study protocol for a randomized controlled trial

“…Thus, PAOP measurements are not mandatory and can be replaced by GEDV to estimate cardiac preload. Furthermore, although not numerically exchangeable, mixed venous oxygen saturation can be approximated by central venous oxygenation saturation [46-48]. Therefore, based on current knowledge, the PiCCO system appears to be superior to the PAC in hemodynamic monitoring of critically ill patients.…”

Central Venous Oxygenation for Mixed Venous Oxygen Saturation

“…The interchangeability or equality of ScvO 2 and SvO 2 has been a matter of great debate over many years in pediatric and adult population [14][15][16][17][18][19][20][21][22][23][24] (►Table 2). In clinical practice, the simplicity of ScvO 2 measurement has always been a factor for clinicians to equate the two variables.…”