Continuous monitoring of mixed venous oxygen saturation in infants after cardiac surgery

Abstract

Continuous mixed venous oxygen saturation (SvO2c) was measured in 16 infants immediately after cardiac surgery. A polyurethane 4F, dual channel catheter (Opticath, Modell U440, Oximetrix) with fiberoptic filaments was introduced into the pulmonary artery during cardiothoracic surgery. The catheters were left in place for an average of 67.5 h (range 27 h -125 h) and there were no catheter-related complications. Correlation between continuous in vivo SvO2 values and in vitro values was satisfactory (r = 0.85), whereas a correlation between SvO2c and arterial oxygen saturation (SaO2) was not found (r = 0.07). The sampled arterial lactate values were inversely correlated to the simultaneously measured SvO2c, but the correlation coefficient was only r = -0.4. There was an inverse correlation between SvO2c and arteriovenous oxygen content difference (Ca-vDO2) (r = -0.82), and a marked inverse correlation to the calculated oxygen utilization ratio (r = -0.97). Therefore SvO2c continuously reflects the overall balance between oxygen consumption and delivery, but the use of SvO2 as a predictor of blood lactate levels is unreliable. A further purpose of the present study was to demonstrate the clinical applications and to show the usefulness of SvO2c-monitoring; particularly as a surveillance and early warning system, as a guide for assessing therapy and its relevance in interpreting other monitored parameters. In our opinion continuous SvO2 measurement is a reliable and valuable indicator of cardiopulmonary function in the immediate post-operative period, even in infants with complicated repair of cardiac malformations.

Systemic Inflammation Increases Energy Expenditure Following Pediatric Cardiopulmonary Bypass

“…Furthermore, children with congenital heart disease often have residual intracardiac shunts that preclude accurate mixed venous assessment. Nevertheless, central venous saturations have been shown to correlate well with mixed venous saturations in critically ill patients, including infants following surgery for congenital heart disease (34,35).…”

Nouvelles techniques de monitorage en réanimation pédiatrique — La ScvO2

“…Le monitorage de la SvO 2 et de la ScvO 2 chez l'enfant n'est pas nouveau et a d'abord été utilisé chez des enfants en postopératoire de chirurgie cardiaque [36,37]. Ces cathéters étaient placés chirurgicalement et avaient l'unique fonction de monitorer la ScvO 2 .…”

Monitoring of O2 transport and tissue oxygenation in paediatric critical care

“…Because cardiac output measurements at present are not routinely available in the neonatal intensive care setting, measurement of SRAv02 provides a limited but valuable insight into the adequacy of tissue oxygenation. Current areas of application of invasive (PAC) measurement of global parameters (DO2, V 0 2 Sv02) in paediatric critical care are intra-and perioperative monitoring in cardiac surgery-including evaluation of cooling techniques for hypothermia during cardiopulmonary bypass (Rah, Dunwiddle & Lower 1984;Schranz et al 1989) or the assessment of different anaesthetic regimens (Laycock e t aZ. 1992); monitoring in septic shock-assessing the effect of blood transfusions, drug treatment (modulating cardiac output), mechanical ventilation, volume resuscitation (Lucking et al 1990;Mink, Murray & Pollack 1990); neonatal extracorporal membrane oxygenation; and monitoring treatment with inhaled nitric oxide for pulmonary hypertension uournois e f al.…”