Changes in jugular bulb oxygenation in patients undergoing warm coronary artery bypass surgery (34–37°C)

Changes in cerebral oxygenation during cold (28°C) and warm (34°C) cardiopulmonary bypass using different blood gas strategies (alpha‐stat and pH‐stat) in patients undergoing coronary artery bypass graft surgery

“…In contrast, SjO 2 less than 50% was observed in the normocapnic (PaCO 2 ranged from 4.8 kPa to 5.3 kPa) patients at a jugular bulb temperature of 36°C. In addition, SjO 2 and AjDO 2 have been shown to be dependent on arterial carbon dioxide during warm CPB (34°C) with pH‐stat management (11).…”

“…Jugular bulb oxygenation has been shown to be dependent on arterial carbon dioxide during warm CPB (11), and Hänel et al (12) found that mild hypercapnia prevents SjO 2 desaturation during rewarming from hypothermic CPB. However, to the best of our knowledge, no previous reports have compared the effect of CPB temperatures (28°C and 34°C) and blood gas management (alpha‐stat and pH‐stat) on jugular bulb oxygen saturation (SjO 2 ) and arterial‐jugular bulb oxygen content difference (AjDO 2 ).…”

A reply

“…Dr Alston provides a perfectly valid explanation of why S j o 2 less than 50% occurs during cardiopulmonary bypass and why, postoperatively, hyperventilation leads to reduced arterial carbon dioxide tension ( P a co 2 ), cerebral vasoconstriction, decreased cerebral perfusion and hence increase in oxygen extraction and reduced S j o 2 . We recently studied the effect of P a co 2 on S j o 2 [2], but found that it explains only 34% of the variance of S j o 2 during warm CPB.…”