124 S. Diop et al.: J Extra Corpor Technol 2025, 57, 123--128
be anticipated and eventually corrected before resuming CPB, mainly by lowering the rate of sweep gas inflow. So, this study aimed to investigate the change in the acid-base balance and the electrolyte composition of the blood contained in the cardiotomy reservoir, during circulatory arrest in a patient undergoing PAE.
Methods Patients
A retrospective analysis was performed on all patients undergoing PAE during this period from January to April 2024. During this period, to improve our local CPB management, arterial blood gas was sampled at the beginning and the end of the first DHCA to better adjust the rate of sweep gas flow. Patients under 18 years old, pregnant women, and patients( or their relatives) who refused the use of their medical data for study purposes were not included.
Ethics
This study has been approved by the ethical committee of the Marie Lannelongue Surgical Center( Ethical Committee IRB N ° 00012157), Paris Saint Joseph Hospital Group, Le Plessis Robinson, France. According to French law, all patients included were informed of the use of their medical data for the study purposes, and their right to refuse or withdraw from participation at any time.
Anaesthetic and cardiopulmonary bypass management
Anesthesia management
Anesthesia care was provided according to the local department protocol. Invasive blood pressure monitoring of all patients was achieved by inserting a left femoral arterial catheter under local anesthesia before the induction of general anesthesia( GA). Patients were then put under GA via intravenous injections of the following: Sufentanil at 0.3 lg / kg, Etomidate at 0.3--0.4 mg / kg, and Rocuronium at 0.4 mg / kg. GA was maintained by a target-controlled infusion( TCI) of Propofol and Sufentanil, and a continuous infusion of the neuromuscular blocking agent to avoid shivering during the cooling and rewarming processes. Patients were put under mechanical ventilation with a tidal volume of 6--8 mL per kg of predicted body weight, and a positive end-expiratory pressure( PEEP) of 5cmH 2 O. The respiratory rate was adjusted to maintain an arterial carbon dioxide pressure( PaCO 2) ranging from 35 to 45 mmHg, and the fraction of inspired O 2( FiO 2) was adjusted to target a blood oxygen saturation( SpO 2) above 94 %, before and after bypass. A pulmonary arterial catheter( Swan-Ganz COmbo V 7.5 Fr, Edwards Lifesciences, Irvine, CA 92614 USA) was inserted, right after the induction of general anesthesia, under ultrasound guidance, allowing continuous measurements of the pulmonary pressure, the cardiac output, and the venous oxygen saturation, allowing optimal hemodynamic management both before initiation and after separation from CPB. During the procedure, the catheter is pulled back into the right ventricle on surgical demand to not interfere with material removal into the pulmonary arteries. The catheter is then inserted into the right pulmonary artery by the surgeon. A single dose of 120 mg of methylprednisolone was injected, for cerebral protection, during the cooling period, once the patient’ s temperature reached 25 ° C. A single dose of 1000 mg of sodium thiopental was administered when the temperature reached 20 ° C to suppress any residual cerebral activity before the DHCA.
CPB management
CPB was established with a nonpulsatile centrifugal pump( Essenz TM Perfusion System, Livanova TM, Eastbourne Terrace, London, England W2 6LG) and blood cardioplegia. The circuit consisted of a membrane oxygenator( 8F, Inspire membrane oxygenator, Livanova TM, Eastbourne Terrace, London, England W2 6LG), a pump, and cannulas. CPB prime consisted of 500 mL of albumin at 4 %, 1000 mL of Ringer’ s lactate solution, and 250 mL of a sodium bicarbonate solution at 1.4 %. The venous cannulas were inserted in each vena cava, and the arterial cannula was inserted into the ascending aorta. Before cooling, an asanguineous priming of CPB is done to obtain hemodilution, with a hemoglobin level target between 9 and 10 g / dL and, if needed, by total blood sequestration( the volume sequestrated would have to be replaced with an equivalent volume of crystalloid). At the beginning of CPB, the membrane fraction of O 2( F m O 2) was set to 60 %, and was then increased to 80 % or above during the cooling process( as soon as the esophageal temperature reached 35 ° C). The patient’ scoretemperature was monitored at two sites: the bladder and the esophagus. Patients were only cooled by means of the oxygenator heat exchanger( without exceeding a gradient of 10 ° C between the arterial outlet temperature and the venous inflow temperature) at a rate of approximately 1 ° C every 2--3 min. On average, it takes between 40 and 60 min to obtain the targeted temperature. Once the 30 ° C threshold was reached, the cardiac index( CI) was progressively lowered at an average rate of 0.05--0.1 L / min / m 2 per degree Celsius to reach 1.8 L / min / m 2 at 18 ° C [ 8 ]. The temperature was then maintained at 18 ° C for the duration of the DHCA. Hyperkalemic blood cardioplegia was administered through the aortic root for myocardial protection immediately after aortic cross-clamping and was repeated every 20 min. Between each circulatory arrest, a reperfusion period of at least 10 min was respected. The CI was then progressively increased during the rewarming phase, at the same rate, once the 20 ° C threshold was reached, to restore the patient’ s baseline CI. Rewarming was achieved at a rate inferior to 0.5 ° C per minute, without exceeding a gradient of 10 ° C between the arterial outlet temperature and the venous inflow temperature, when the arterial temperature was below 30 ° C, and without exceeding a gradient of 5 ° Cwhen the temperature was above 30 ° C [ 9 ]. Mean arterial pressure wasmaintainedbetween60and80mmHgwiththehelpofa continuous infusion of norepinephrine( 0.2 mg / mL), if necessary. Acid-base management was achieved through an alphastat strategy during both cooling and rewarming.