A retrospective cohort of 200 adults describes normothermic cardiopulmonary bypass guided by indexed flow, cerebral oximetry, and oxygen delivery, with vasopressors reserved for clinical need. Operating-room extubation occurred in 86%, stroke in 3%, and acute kidney injury in 1%. The predominantly valve-surgery cohort had no comparison group. These findings describe one center’s experience and do not establish the safety or superiority of lower pressure targets.
Looking Beyond Pressure During Cardiopulmonary Bypass
Mean arterial pressure is an essential part of perfusion monitoring, but a pressure reading alone cannot describe oxygen delivery to the brain and other organs. Nikita Chibisov and colleagues at Botkin Hospital in Moscow examined their institution’s experience with normothermic cardiopulmonary bypass managed using indexed pump flow, cerebral oximetry, calculated indexed oxygen delivery, and selective rather than routine vasopressor administration. Their report describes the outcomes and physiologic measurements of 200 adults. It does not compare this strategy with conventional pressure management or demonstrate that lower pressure targets improve recovery.
The authors’ central premise is that pressure should be interpreted alongside blood flow, arterial oxygen content, vascular resistance, and indicators of regional and systemic oxygen balance. Increasing pressure through vasoconstriction does not necessarily establish that tissue oxygen delivery has improved. Conversely, apparently preserved flow or oxygenation measurements cannot by themselves establish that every organ is adequately perfused. The study therefore provides an institutional description of an integrated monitoring approach, rather than a validated replacement for individualized clinical assessment.
Study Design and Patient Population
This single-center retrospective descriptive cohort included elective and urgent adult cardiac operations performed between June 2023 and December 2025. Eligible cases required complete anesthesia–perfusion records, cerebral oxygenation measurements, circuit-derived venous oxygen saturation, calculated oxygen-delivery data, and early outcomes. Patients undergoing circulatory arrest were excluded, as were cases with missing key documentation. The requirement for complete records is relevant when considering potential selection bias.
Valve procedures dominated the population: 102 patients underwent aortic valve replacement, 62 underwent mitral valve replacement, and 28 underwent mitral valve repair. Eight underwent aortic valve replacement combined with coronary artery bypass grafting. Thus, 96% underwent isolated valve procedures. These results should not be assumed to apply to isolated coronary surgery, complex aortic operations, circulatory arrest, or other substantially different clinical populations.
How the Institutional Strategy Was Applied
Bypass was conducted with a Stockert S5 heart–lung machine and an indexed pump-flow target of 2.2–2.4 L/min/m². Mean arterial pressures of 40–60 mmHg were generally accepted when indexed flow was preserved and the broader monitoring assessment did not suggest impaired oxygen balance. Vasopressors were not used routinely, but vasoactive treatment remained available when hypotension persisted or the clinical context raised concern about inadequate perfusion. These ranges describe the study center’s practice; they are not established safety thresholds from this investigation.
When pressure exceeded 60 mmHg with preserved flow, the center administered nitroglycerin boluses to reduce vascular resistance. Low-pressure episodes prompted physiologic and technical reassessment rather than being treated as desirable targets. Potential corrective measures included changes to pump flow, venous drainage, volume status, hemoglobin concentration, acid–base management, anesthetic depth, and vasoactive support. The reported transfusion threshold was approximately 75 g/L, interpreted alongside oxygen-delivery and oxygenation measurements and the overall clinical situation.
Cerebral Oximetry and Oxygen-Delivery Assessment
Bilateral cerebral oxygenation was monitored using near-infrared spectroscopy. Baseline regional cerebral oxygen saturation was recorded before mechanical ventilation while patients breathed room air. The investigators subsequently recorded the maximal relative decrease during bypass. A disproportionate fall prompted review of venous drainage, cannula position, circuit performance, pump flow, hemoglobin, oxygenation, acid–base status, and surgical conditions. If reduced cerebral oxygenation appeared related to inadequate flow or oxygen delivery, flow was increased when technically and clinically feasible.
The paper reports mean baseline right and left cerebral saturations of 57.5% and 58.5%, respectively. The mean maximal relative decrease during bypass was 28.5%, with a reported range of 24%–38%. These are relative reductions from baseline, not absolute percentage-point changes. The aggregate measurements do not describe the duration of each desaturation or establish that the reported reductions were harmless. Individualized cerebral autoregulation thresholds and time-resolved pressure exposure were not analyzed.
Venous oxygen saturation was sampled from the bypass circuit and averaged 67.4%. This measurement should not be equated with pulmonary artery catheter-derived mixed venous saturation. The authors also calculated indexed oxygen delivery from pump flow and arterial oxygen content, incorporating hemoglobin, arterial oxygen saturation, and arterial oxygen tension. They reported a mean DO₂i of 611 ± 74 mL/min/m². This is a reported study value, not a proposed clinical target. The paper does not provide the paired patient-level flow and arterial oxygen-content inputs needed to independently reproduce that aggregate calculation.
Early Postoperative Outcomes
Operating-room extubation was achieved in 172 of 200 patients, or 86.0%, with a 95% confidence interval of 80.5%–90.1%. Six patients experienced stroke, corresponding to 3.0% and a confidence interval of 1.4%–6.4%. Acute kidney injury was reported in two patients, or 1.0%, with a confidence interval of 0.3%–3.6%. Six patients required venoarterial ECMO, again representing 3.0% of the cohort.
The authors classified 178 patients, or 89.0%, as having no major early postoperative complications. This was a separately abstracted patient-level recovery measure, not a value obtained by subtracting the listed complications from the total population. The study reported no need to abandon the institutional strategy because of clinically relevant progressive metabolic acidosis. However, absence of that particular warning sign does not establish the absence of regional hypoperfusion or other organ injury.
Early extubation is best understood in the context of the center’s broader fast-track anesthesia and postoperative recovery practices. The contribution of perfusion management cannot be separated from patient selection, surgical factors, anesthetic care, myocardial protection, or transfusion practices. Similarly, the low observed frequency of acute kidney injury cannot be attributed to the pressure strategy without an appropriate comparison and adjustment for baseline risk.
What Perfusion Teams Can Take From the Report
The most useful educational message is the importance of interpreting multiple perfusion signals together. Cerebral oximetry, circuit-derived venous oxygen saturation, hemoglobin, gas exchange, acid–base trends, and technical circuit assessment can provide context when pressure and flow measurements appear discordant. The report also emphasizes that a vasopressor-sparing approach is different from an absolute prohibition on vasoactive treatment: clinical concern could still prompt intervention.
Important limitations remain. The investigation was retrospective, noncomparative, and confined to one institution. Baseline demographic and risk-score variables were unavailable in the analyzable aggregate dataset, restricting risk adjustment. There was no multivariable causal modeling, no formal comparison of pressure strategies, and no detailed analysis of the relationship between physiologic exposures and postoperative events. Prospective comparative studies with time-resolved measurements and clearly defined outcomes are needed before this experience can support stronger claims about safety, effectiveness, or generalizability.
Attribution: © 2026 Annals of Cardiac Anaesthesia. The unchanged source article is shared under CC BY-NC-ND 4.0. This independently written IPA summary accompanies the source; the cover artwork is conceptual.
Original Article
Chibisov N, Kornienko A, Malyshev A, Rodionov E, Glushenko I, Shtrymov M. Cerebral oxygenation-guided indexed-flow normothermic cardiopulmonary bypass with vasopressor-sparing pressure management: A retrospective descriptive cohort study. Annals of Cardiac Anaesthesia. 2026;29:587–593. Read the original article.
