More than 1 million patients worldwide undergo cardiac surgery each year, amounting to approximately 123 per 100,000 population.¹ Cardiopulmonary bypass has been central to this success, facilitating the possibility of corrective surgery for patients with various types of cardiac pathologies. However, cardiopulmonary bypass is not benign, and with the combination of surgical stimulation, hypothermic circulation, exposure to nonbiologic surfaces, linear blood flow, and dynamic changes in anesthesia depth, there is a resultant systemic inflammatory response and activation of the sympathetic and renin-angiotensin systems (Fig 1).² On the whole, most patients undergoing cardiac surgery require vasoactive agents for reduced blood pressure and cardiac output. However, occasionally the combination of these insults results in vasoconstriction and contributes to clinical elevations in arterial blood pressure.

The ideal blood pressure target during cardiopulmonary bypass has been debated for decades. Indeed, in a recent survey of over 500 clinicians, the highest mean arterial pressure clinicians considered acceptable during cardiopulmonary bypass in adult patients was 84 ± 7 mmHg, while the lowest acceptable mean arterial pressure was 55 ± 7 mmHg.³ Respondents endorse their tightest acceptable mean arterial pressure range to be during cardiopulmonary bypass (mean 16 ± 7 mmHg) instead of before (19 ± 7 mmHg) or after (20 ± 7 mmHg) cardiopulmonary bypass. Clinicians also report less tolerance of high blood pressures and target lower values during surgery involving the thoracic aorta or when there is surgical bleeding, while they tend to target or accept higher blood pressures in certain conditions, such as in patients with a history of carotid stenosis, stroke, hypertension, or chronic kidney disease.³ Interestingly, all of the acceptable blood pressure levels assessed varied by respondent profession type (ie, cardiac surgery, cardiac anesthesia, perfusion), further highlighting the lack of agreement on ideal targets.