Continuous measurement of oxygen consumption during cardiopulmonary bypass: description of the method and in vivo observations

Evidence for a significant myocardial contribution to total metabolic burden during hypothermic cardiopulmonary bypass: a study of continuously measured oxygen consumption and arterial lactate levels in pigs

“…Our study, based on the continuous measurement of VO 2 , demonstrates that the major component of the increase in arterial lactate levels and VO 2 during rewarming was occurring during this brief period. The acute increase in VO 2 , which we have previously described, 10 was accompanied by an acute increase in lactate. In fact, the immediate post-ACC release period is the only period that lactate levels increased significantly and accounted for 68% of the total increase during the entire rewarming period.…”

“…Indeed, in our previous study with the same protocol and technique, we found a significant underestimation of VO 2 calculated from the reversed Fick from the pump flow and arterial and venous oxygen contents as compared to the directly measured VO 2 . 10 Thus, ERO 2 derived in our study may be overestimated. Nonetheless, using the independent measurements of VO 2 and DO 2 avoids the problem of mathematical coupling when DO 2 is derived from VO 2 .…”

“…11 Our adaptation for use during CPB has been described elsewhere. 10 Oxygen delivery, oxygen extraction ratio (ERO 2 ) and lactate. Arterial blood samples were taken after starting CPB (15 min), at the end of hypothermia (100 min), before removal of the ACC (120 min), 10 min after removal of the ACC (130 min), 150 min and close to the end of CPB (165 min) (Figure 1).…”

“…We recently reported a technique to continuously measure VO 2 during CPB using respiratory mass spectrometry, and obtained detailed information about the changes and absolute values of VO 2 during hypothermic CPB in an animal model. 10 We found that VO 2 varied significantly between individuals at any given temperature, and was nonlinearly related to the change of temperature. More interestingly, we noticed an acute increase in VO 2 immediately after the release of the aortic crossclamp (ACC), which was attributed to myocardial oxygen consumption.…”

Accurate Measurement of Systemic Oxygen Consumption in Ventilated Children with Congenital Heart Disease

“…We have adapted the method to continuously measure VO 2 with a variety of pediatric ventilators and anesthesia ventilators before, during, and after CPB, using the AMIS 2000 Medical Respiratory Mass Spectrometer System (Innovision A/C Odense, Denmark). Our combination of techniques and equipment makes respiratory mass spectrometry a unique and powerful tool in multiple settings: in the cardiac catheterization laboratory (SchulzeNeick, Li et al 2002 ;, in the operating room (Li, Stokoe et al 2004), and in the ICU (Li, Hoschtitzky et al 2004;Li, Schulze-Neick et al 2000;Schulze-Neick, Li et al 2001).…”