J Extra Corpor Technol 2025, 57, 123--128 Ó The Author( s), published by EDP Sciences, 2025 https:// doi. org / 10.1051 / ject / 2025014
Available online at: ject. edpsciences. org
ORIGINAL ARTICLE
Acid-base status of the blood contained in the cardiotomy reservoir during deep hypothermic circulatory arrest at 18 ° C
Sylvain Diop 1, 2,*, Marwan Nader 1, Elie Fadel 3, Maria Cristina Kassab 1, Hamdi Ghadbane 4, Iolanda Ion 1, and Jacques Thes 1, 2, 4
1 Department of Anesthesiology, Marie Lannelongue Hospital, Paris Saint Joseph Hospital, 133 Avenue de la Résistance, 92350 Le Plessis Robinson, France 2 Cardiothoracic Intensive Care Unit, Marie Lannelongue Hospital, Paris Saint Joseph Hospital, 133 Avenue de la Résistance,
92350 Le Plessis Robinson, France 3 Department of Vascular and Thoracic Surgery, Marie Lannelongue Hospital, Paris Saint Joseph Hospital, 133 Avenue de la Résistance, 92350 Le Plessis Robinson, France 4 Perfusionist Team, Department of Anesthesiology, Marie Lannelongue Hospital, Paris Saint Joseph Hospital, 133 Avenue de la Résistance, 92350 Le Plessis Robinson, France Received 10 February 2025, Accepted 27 April 2025
Abstract – Background: During deep hypothermic circulatory arrest( DHCA) for pulmonary artery endarterectomy( PAE), the blood volume stored in the cardiotomy reservoir circulates through the oxygenator via the arterial shunt line, where it remains oxygenated and decarboxylated. The aim of the study was to investigate the change in the acid-base balance of the blood contained in the cardiotomy reservoir during DHCA. Methods: A four-month retrospective analysis was conducted on patients undergoing PAE. The sweep gas inflow and the inspired fraction of O 2 were kept constant throughout the duration of DHCA. Arterial blood gases were sampled at the beginning and at the end of the DHCA and were analyzed according to the alpha-stat and pH-stat strategies. Results: Twenty-four patients were included with a mean age of 59.2(± 15.7) years. The mean duration of DHCA was 15.2(± 4.1) min and the mean sweep gas inflow was 1.4(± 0.8) L / min. Initial pH and PaCO 2 were 7.31(± 0.09) and 43.2(± 9.9) mmHg, respectively, and final pH and PaCO 2 were 7.51(± 0.14), p < 0.001 and 23.4(± 11.9) mmHg, p < 0.001. There was a significant correlation between the sweep gas inflow and the post-DHCA pH( r = 0.797). Conclusion: The pH increases significantly during the DHCA according to the sweep gas inflow. Decreasing the sweep gas inflow between 0.5 and 1.0 L / min allows for limiting the pH variation during the DHCA period.
Key words: Deep hypothermic circulatory arrest, Pulmonary artery endarterectomy, Acid base, pH-stat, Alpha-stat, Cerebral blood flow. Introduction
Pulmonary artery endarterectomy( PAE) is a complex surgery performed under cardiopulmonary bypass( CPB) to treat certain phenotypes of chronic thromboembolic pulmonary hypertension [ 1 ]. To allow the surgeon to adequately remove the clot material from inside the pulmonary arteries, a bloodless surgical field is required and obtained through one, or more, short periods of deep hypothermic circulatory arrest( DHCA)( CA being the complete interruption of CPB) after having cooled the body to 18 ° C [ 1 ]. During DHCA, the blood volume, outside the residual blood volume of the body vessels and
* Corresponding author: menes. diop @ gmail. com tissue, is stored in the cardiotomy reservoir. During that period, according to our local CPB management, the blood circulates through the oxygenator via the arterial shunt line, at a flow ranging from 0.4 to 0.8 L / min and remains oxygenated and decarboxylated on account of the sweep gas inflow. Recommendation from the American Society of Extracorporeal Technology advocates setting up the sweep gas flow to maintain blood at normocapnic level [ 2 ]. However, to the extent of our knowledge, there is no clinical data regarding the composition of the blood reinjected after this period of DHCA. We hypothesize that the composition of the blood changes dynamically during the time of DHCA. As pH and partial pressure of carbon dioxide( PaCO 2) dynamically modify cerebral blood flow, it could have some clinical impact on brain perfusion [ 3--7 ]. If present, acid-base disturbances occurring during DHCA could
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