Changes in hemodynamic variables during hypothermic cardiopulmonary bypass

Influence of arterial carbon dioxide tension on systemic vascular resistance in patients undergoing cardiopulmonary bypass

“…The effects of arterial carbon dioxide tension have also been investigated in patients undergoing cardiopulmonary bypass (3, 4, 12, 13). In a study by Alston et al, no significant changes in systemic vascular resistance could be observed when two groups of patients undergoing either a-stat or pH-stat management were compared; however, in both groups of pa-tients systemic vascular resistance increased with duration of cardiopulmonary bypass (4). The authors suggested, that the progressive increase in SVR was related to changes in vasomotor tone due to impairment of tissue perfusion and active constriction of metarterioles and precapillary sphincters (4).…”

“…This study demonstrates that 1) in patients undergoing hypothermic cardiopulmonary bypass systemic vascular resistance is higher under a-stat than under pH-stat conditions, and that 2) this difference in systemic vascular resistance is equivalent to haemodynamic effects associated with changes in PaC02 during normothermia and spontaneous circulation. Changes in systemic haemodynamics during cardiopulmonary bypass may be related to several factors such as changes in flow rate, flow characteristics, hypothermia and viscosity (4,5). The effects of arterial carbon dioxide tension on systemic haemodynamics and organ blood flow are, however, still a matter of discussion (6)(7)(8).…”

Pulsatile Versus Nonpulsatile Cardiopulmonary Bypass Flow: An Evidence-Based Approach

“…Thirty‐nine studies were excluded after examining the entire manuscript. The reasons for exclusion were different target population (7 studies), 9,19–22 different intervention (6 studies), 23–28 outcome of interest was not measured (24 studies), 7,10–12,29–48 and multiple reasons (2 studies) 49,50 …”

“…9 On the other hand, several clinical studies have been unable to detect a benefit associated with PP. [10][11][12][13][14][15] Although the subject has been discussed frequently during the past decades, studies have advocated conflicting recommendations. As a result, the optimal perfusion characteristic during CPB is still in debate.…”

“…Additionally, PP was found to decrease the retention of fluid into the lungs 9 . On the other hand, several clinical studies have been unable to detect a benefit associated with PP 10–15 …”