J Extra Corpor Technol 2026, 58, 73--78 Ó The Author( s), published by EDP Sciences, 2026 https:// doi. org / 10.1051 / ject / 2025050
Available online at: ject. edpsciences. org
TECHNIQUE OR APPLICATION
A comparative study of the effect of slow and rapid initiation of cardiopulmonary pump on tissue oxygenation index and ischemic complications
Mostafa Bagherinasab( MSc) 1, Sahar Rezaei( MSc) 2, Ali Reza Moradi( MSc) 3, Ali Jabbari( MD) 4, Amin Noori( MSc) 3, Zachary Archer( MSc, CP) 5, and Nathaniel H. Darban( PhD, CP) 5,*
1 Baqiyatallah University of Medical Sciences, 19395-5487, Tehran, Iran 2 Student Research Committee, Faculty of Nursing, Tehran University of Medical Sciences, 1417935840 Tehran, Iran 3 Student Research Committee, Faculty of Nursing, Baqiyatallah University of Medical Sciences, 19395-5487 Tehran, Iran 4 Golestan University of Medical Science, 4918936316 Gorgan, Iran 5 College of Health Sciences, Cardiovascular Science Program, Glendale, Arizona 85308, USA
Received 10 June 2025, Accepted 2 September 2025
Abstract – Introduction: Although the use of the heart-lung machine( HLM) is routine in cardiac operating theaters, there is still a lack of evidence-based guidelines concerning the optimal speed to reach full flow during initiation to reduce critical episodes of cerebral ischemia. Therefore, we have designed a study to compare two distinct initiation times for the commencement of cardiopulmonary bypass( CPB). Methods: We conducted a randomized, monocentric, double-blind, prospective study to assess the impact of two different CPB initiation speeds-- rapid initiation at 30 s and slow initiation at 180 s-- on cerebral tissue oxygenation( TOI via NIRS), arterial oxygen pressure, hematocrit( HCT) variation, and the incidence of postoperative delirium. The target flow rate was set at 2.4 L / min / m 2, with adjustments made according to the patient’ s body surface area. Results: The absolute values of the tissue oxygenation index( TOI) and HCT showed no differences between the study during the first 180 s following commencement of CPB. Patients in the fast group exhibited significantly lower arterial oxygen pressure at the initiation of the( P < 0.05). Additionally, patients in the fast group experienced a higher incidence of delirium in the second and third days following surgery. While clinically relevant, the elevated incidence of delirium fell short of being statistically significant, with postoperative days 2 and 3 having P-values of 0.06 and 0.08, respectively. Conclusion: The results of this study indicate that, despite the absence of a significant difference in TOI between the study groups, patients in the slow group exhibited a not statistically significant trend for a lower incidence of delirium, as defined by CAMICU-7, in comparison to those in the fast group.
Key words: Initiation time, Cardiopulmonary bypass, Tissue oxygenation index, Ischemic complications, Near-infrared spectroscopy.
Introduction
The optimal speed or time frame required to achieve complete cardiac output( CO) from the heart-lung machine( HLM) during the initiation of cardiopulmonary bypass( CPB) is not clearly defined by either the manufacturer or the scientific community [ 1 ]. Approximately three decades ago, it was reported that, in the majority of cases, complete CO or CPB flow could be achieved within 30 s [ 2 ]. The dissemination of this information has continued despite the absence of scientific validation. The initiation times vary significantly across different institutions, ranging from as short as 10 s to as long as 20 s,
* Corresponding author: ndarba @ midwestern. edu and in some cases, extending up to 300 s, particularly in instances such as aortic dissection [ 1, 3 ]. Theoretical considerations indicate that slower initiation times may provide neurological advantages [ 4 ]. Unlike rapid initiation, a gradual ramp-up period allows for a more gradual hemodilution, which is linked to enhanced endogenous compensation for the decreasing oxygen supply [ 5 ]. This process may consequently lead to a reduction in the incidence of neurological complications [ 1 ].
The 30- and 180-second durations were selected based on previous perfusion protocols reported in the literature and clinical feasibility [ 1, 4, 5 ]. The 30-second rapid initiation reflects conventional practice, whereas the 180-second approach was chosen to provide a distinctly gradual hemodilution process for comparative evaluation.
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