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Jarry S, Couture EJ, Beaubien-Souligny W, Fernandes A, Fortier A, Ben-Ali W, Desjardins G, Huard K, Mailhot T, Denault AY. Clinical relevance of transcranial Doppler in a cardiac surgery setting: embolic load predicts difficult separation from cardiopulmonary bypass. J Cardiothorac Surg 2024; 19:90. [PMID: 38347542 PMCID: PMC10863099 DOI: 10.1186/s13019-024-02591-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 01/30/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND During cardiac surgery, transcranial Doppler (TCD) represents a non-invasive modality that allows measurement of red blood cell flow velocities in the cerebral arteries. TCD can also be used to detect and monitor embolic material in the cerebral circulation. Detection of microemboli is reported as a high intensity transient signal (HITS). The importance of cerebral microemboli during cardiac surgery has been linked to the increased incidence of postoperative renal failure, right ventricular dysfunction, and hemodynamic instability. The objective of this study is to determine whether the embolic load is associated with hemodynamic instability during cardiopulmonary bypass (CPB) separation and postoperative complications. METHODS A retrospective single-centre cohort study of 354 patients undergoing cardiac surgery between December 2015 and March 2020 was conducted. Patients were divided in tertiles, where 117 patients had a low quantity of embolic material (LEM), 119 patients have a medium quantity of microemboli (MEM) and 118 patients who have a high quantity of embolic material (HEM). The primary endpoint was a difficult CPB separation. Multivariate logistic regression was used to determine the potential association between a difficult CPB separation and the number of embolic materials. RESULTS Patients who had a difficult CPB separation had more HITS compared to patients who had a successful CPB separation (p < 0.001). In the multivariate analysis, patients with MEM decreased their odds of having a difficult CPB weaning compared to patients in the HEM group (OR = 0.253, CI 0.111-0.593; p = 0.001). In the postoperative period patients in the HEM group have a higher Time of Persistent Organ Dysfunction (TPOD), a longer stay in the ICU, a longer duration under vasopressor drugs and a higher mortality rate compared to those in the MEM and LEM groups. CONCLUSION The result of this study suggests that a high quantity of cerebral embolic material increases the odds of having a difficult CPB separation. Also, it seems to be associated to more complex surgery, a longer CPB time, a higher TPOD and a longer stay in the ICU. Six out of eight patients who died in this cohort were in the HEM group.
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Affiliation(s)
- Stéphanie Jarry
- Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, 5000 Belanger Street, Montreal, QC, H1T 1C8, Canada
| | - Etienne J Couture
- Department of Anesthesiology and Department of Medicine, Division of Intensive Care Medicine, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
| | | | - Armindo Fernandes
- Perfusion Service, Montreal Heart Institute, Université de Montréal, Montreal, QC, Canada
| | - Annik Fortier
- Montreal Health Innovations Coordinating Center, Montreal Heart Institute, Montreal, QC, Canada
| | - Walid Ben-Ali
- Department of Surgery and Department of Cardiology, Montreal Heart Institute, Montreal, QC, Canada
| | - Georges Desjardins
- Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, 5000 Belanger Street, Montreal, QC, H1T 1C8, Canada
| | - Karel Huard
- Université de Montréal, Montreal, QC, Canada
| | - Tanya Mailhot
- Research Center, Montreal Heart Institute, and Faculty of Nursing, Université de Montréal, Montreal, QC, Canada
| | - André Y Denault
- Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, 5000 Belanger Street, Montreal, QC, H1T 1C8, Canada.
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Puthettu M, Vandenberghe S, Balafas S, Di Serio C, Singjeli G, Pagnamenta A, Demertzis S. Optimizing CO2 field flooding during sternotomy: In vitro confirmation of the Karolinska studies. PLoS One 2024; 19:e0292669. [PMID: 38194426 PMCID: PMC10775975 DOI: 10.1371/journal.pone.0292669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 09/26/2023] [Indexed: 01/11/2024] Open
Abstract
Although CO2 field-flooding was first used during cardiac surgery more than 60 years ago, its efficacy is still disputed. The invisible nature of the gas and the difficulty in determining the "safe" quantity to protect the patient are two of the main obstacles to overcome for its validation. Moreover, CO2 concentration in the chest cavity is highly sensitive to procedural aspects, such suction and hand movements. Based on our review of the existing literature, we identified four major factors that influence the intra-cavity CO2 concentration during open-heart surgery: type of delivery device (diffuser), delivery CO2 flow rate, diffuser position around the wound cavity, and its orientation inside the cavity. In this initial study, only steady state conditions were considered to establish a basic understanding on the effect of the four above-mentioned factors. Transient factors, such as suction or hand movements, will be reported separately.
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Affiliation(s)
- Mira Puthettu
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, Lugano, Switzerland
- Laboratory of Cardiovascular Engineering, Laboratories for Translational Research EOC (LRT-EOC), Bellinzona, Switzerland
| | - Stijn Vandenberghe
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, Lugano, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
| | - Spyros Balafas
- University Centre for Statistics in the Biomedical Sciences, Vita-Salute San Raffaele University, Milano, Italy
| | - Clelia Di Serio
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
- University Centre for Statistics in the Biomedical Sciences, Vita-Salute San Raffaele University, Milano, Italy
- Clinical Trial Unit (CTU), Ente Ospedaliero Cantonale (EOC), Lugano, Switzerland
| | - Geni Singjeli
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, Lugano, Switzerland
| | - Alberto Pagnamenta
- Clinical Trial Unit (CTU), Ente Ospedaliero Cantonale (EOC), Lugano, Switzerland
- Department of Intensive Care, Ente Ospedaliero Cantonale (EOC), Lugano, Switzerland
- Division of Pneumology, University of Geneva, Geneva, Switzerland
| | - Stefanos Demertzis
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, Lugano, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
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3
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Ferrante MS, Pisano C, Van Rothem J, Ruvolo G, Abouliatim I. Cerebrovascular events after cardiovascular surgery: diagnosis, management and prevention strategies. KARDIOCHIRURGIA I TORAKOCHIRURGIA POLSKA = POLISH JOURNAL OF CARDIO-THORACIC SURGERY 2023; 20:118-122. [PMID: 37564967 PMCID: PMC10410632 DOI: 10.5114/kitp.2023.130020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/06/2023] [Indexed: 08/12/2023]
Abstract
Introduction Cerebrovascular events after cardiac surgery are among the most serious complications, related to a greater risk of patient mortality. This problem can occur following the formation of gas emboli during open heart surgery. Aim To address all the mechanisms that can lead to embolic events after cardiovascular surgery, how to manage them and how to possibly prevent them. Material and methods A search of the PubMed database was conducted. We reviewed the clinical literature and examined all aspects to identify the root causes that can lead to the formation of emboli. Results Among the studies reviewed, it was found that the main causes include manipulation of the aorta, inadequate deaeration after cardiac surgery, and blood-component contact of extracorporeal circulation. It has been reported that gas emboli can lead to deleterious damage such as damage to the cerebral vascular endothelium, disruption of the blood-brain barrier, complement activation, leukocyte aggregation, increased platelet adhesion, and fibrin deposition in the microvascular system. Conclusions Stroke after cardiovascular surgery is one of the most important complications, with a great impact on operative mortality and patient survival. Efforts have been made over time to understand all the pathophysiological mechanisms related to this complication, with the aim of reducing its incidence. One of the goals should be to improve both the surgical technique and the perfusion modality and minimize the formation of air bubbles or to facilitate their elimination during the cardiopulmonary bypass procedure.
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Affiliation(s)
| | - Calogera Pisano
- Cardiac Surgery Division, Tor Vergata University Hospital, Rome, Italy
| | | | - Giovanni Ruvolo
- Cardiac Surgery Division, Tor Vergata University Hospital, Rome, Italy
| | - Issam Abouliatim
- Cardiovascular and Thoracic Surgery Department, Clinique Pasteur, Toulouse, France
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4
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Ishida M, Takahashi S, Okamura H. Comparison of bubble removal performances of five membrane oxygenators with and without a pre-filter. Perfusion 2023; 38:530-538. [PMID: 35105222 DOI: 10.1177/02676591211064960] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
When employing minimal invasive extracorporeal circulation (MiECC), the removal of bubbles in the circuit is important to prevent air embolism. We investigated the bubble removal performance of the FHP oxygenator with a pre-filter and compared it with that of four oxygenators, including the Fusion oxygenator, Quadrox oxygenator, Inspire oxygenator, and FX oxygenator. A closed test circuit filled with an aqueous glycerin solution was used. Air injection (10 mL) was performed prior to the oxygenator, and the number and volume of the bubbles were measured at the inlet and outlet of each oxygenator. At the inlet of the five oxygenators, there were no significant differences in the total number of bubbles detected. At the outlet, bubbles were classified into two groups according to the bubble size: ≥100 μm and <100 μm. Tests were performed at pump flow rates of 4 and 5 L/min. For bubbles ≥100 μm, which are considered clinically detrimental, the FHP was the lowest number and volume of bubbles at both pump flow rates compared to the other oxygenators. Regarding the bubbles <100 μm, the number of bubbles was higher in the FHP than those in others; however, the volume of bubbles was significantly lower at 4 L/min and tended to be lower at 5 L/min. The use of the FHP with the pre-filter removed more bubbles ≥100 μm in the circuit than that by the other oxygenators.
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Affiliation(s)
- Mitsuru Ishida
- Department of Medical Engineering, RinggoldID:%2083943Nerima Hikarigaoka Hospital, Nerima-ku, Japan
| | - Sho Takahashi
- Department of Medical Engineering, RinggoldID:%2083943Nerima Hikarigaoka Hospital, Nerima-ku, Japan
| | - Homare Okamura
- Department of Cardiovascular Surgery, RinggoldID:%2083943Nerima Hikarigaoka Hospital, Nerima-ku, Japan
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Calderone A, Jarry S, Couture EJ, Brassard P, Beaubien-Souligny W, Momeni M, Liszkowski M, Lamarche Y, Shaaban-Ali M, Matta B, Rochon A, Lebon JS, Ayoub C, Martins MR, Courbe A, Deschamps A, Denault AY. Early Detection and Correction of Cerebral Desaturation With Noninvasive Oxy-Hemoglobin, Deoxy-Hemoglobin, and Total Hemoglobin in Cardiac Surgery: A Case Series. Anesth Analg 2022; 135:1304-1314. [PMID: 36097147 DOI: 10.1213/ane.0000000000006155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Regional cerebral oxygen saturation (rS o2 ) obtained from near-infrared spectroscopy (NIRS) provides valuable information during cardiac surgery. The rS o2 is calculated from the proportion of oxygenated to total hemoglobin in the cerebral vasculature. Root O3 cerebral oximetry (Masimo) allows for individual identification of changes in total (ΔcHbi), oxygenated (Δ o2 Hbi), and deoxygenated (ΔHHbi) hemoglobin spectral absorptions. Variations in these parameters from baseline help identify the underlying mechanisms of cerebral desaturation. This case series represents the first preliminary description of Δ o2 Hbi, ΔHHbi, and ΔcHbi variations in 10 cardiac surgical settings. Hemoglobin spectral absorption changes can be classified according to 3 distinct variations of cerebral desaturation. Reduced cerebral oxygen content or increased cerebral metabolism without major blood flow changes is reflected by decreased Δ o2 Hbi, unchanged ΔcHbi, and increased ΔHHbi Reduced cerebral arterial blood flow is suggested by decreased Δ o2 Hbi and ΔcHbi, with variable ΔHHbi. Finally, acute cerebral congestion may be suspected with increased ΔHHbi and ΔcHbi with unchanged Δ o2 Hbi. Cerebral desaturation can also result from mixed mechanisms reflected by variable combination of those 3 patterns. Normal cerebral saturation can occur, where reduced cerebral oxygen content such as anemia is balanced by a reduction in cerebral oxygen consumption such as during hypothermia. A summative algorithm using rS o2 , Δ o2 Hbi, ΔHHbi, and ΔcHbi is proposed. Further explorations involving more patients should be performed to establish the potential role and limitations of monitoring hemoglobin spectral absorption signals.
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Affiliation(s)
- Alexander Calderone
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Stéphanie Jarry
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Etienne J Couture
- Departments of †Anesthesiology.,Medicine, Division of Intensive Care Medicine, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, Quebec, Canada.,Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Quebec, Quebec, Canada
| | - Patrice Brassard
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Quebec, Quebec, Canada.,Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec, Quebec, Canada
| | - William Beaubien-Souligny
- Department of Medicine, Division of Nephrology, Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Mona Momeni
- Department of Acute Medicine, Cardiothoracic and Vascular Anesthesia Section, Cliniques Universitaires Saint-Luc, UC Louvain, Brussels, Belgium
| | - Mark Liszkowski
- Department of Medicine, Cardiology Division, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada.,Critical Care Division, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Yoan Lamarche
- Critical Care Division, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada.,Department of Cardiac Surgery, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Mohamed Shaaban-Ali
- Critical Care Division, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Basil Matta
- Neurosciences Critical Care Unit, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Antoine Rochon
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Jean-Sébastien Lebon
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Christian Ayoub
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Maria Rosal Martins
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Athanase Courbe
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Alain Deschamps
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - André Y Denault
- From the Department of Anesthesiology, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada.,Critical Care Division, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
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6
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Stanley ME, Sellke FW. Neurocognitive decline in cardiac surgery patients: what do we know? J Thorac Cardiovasc Surg 2022:S0022-5223(22)00825-X. [DOI: 10.1016/j.jtcvs.2022.07.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/15/2022] [Accepted: 07/28/2022] [Indexed: 10/16/2022]
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7
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Vandenberghe S, Singjeli G, Demertzis S. Patient tilt improves efficacy of CO 2 field-flooding in minimally invasive cardiac surgery. J Cardiothorac Surg 2022; 17:164. [PMID: 35733212 PMCID: PMC9219288 DOI: 10.1186/s13019-022-01916-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/12/2022] [Indexed: 11/18/2022] Open
Abstract
Objective Space limitations during minimally invasive cardiac surgery impede consistent use of CO2 field-flooding. We compared different gas delivery methods, flow rates and the effect of patient inclination. Methods A gastight model of MICS surgery with internal organs and right thoracotomy wound was created from a mannequin and equipped with a CO2 concentration sensor in the left ventricle. Maximum achievable CO2 concentration was compared for gas delivery via three commercial CO2 diffusors (CarbonMini, Temed, Andocor) and also via a trocar with side port. Gas flow rates of 1, 3, 5 and 8 L per minute were tested. The model was placed either in supine position or with 20° oblique tilt. A simplified transparent model was also created and placed in an optical test bench to evaluate the gas cloud motions via real-time visualization. Results The trocar consistently achieved higher CO2 concentrations inside the left ventricle. At 1 l/min, approximately 2.5 min were needed to fill the supine model to its maximum CO2 concentration, which was limited to a range of 48–82% in the left ventricle. At higher flow rates, filling time and concentration were significantly improved. In a tilted model, all devices and all flow rates generated on average 99% CO2 in the ventricle. Imaging revealed constant gas exchange via the main incision, with CO2 outflow via bottom and air inflow via the top of the incision. Conclusions CO2 field flooding in minimally invasive cardiac surgery is highly effective if the patient is tilted. Else a flow rate of 5 l/min is recommended to achieve the same protection. Supplementary Information The online version contains supplementary material available at 10.1186/s13019-022-01916-5.
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Affiliation(s)
- Stijn Vandenberghe
- Faculty of Biomedical Sciences, Università Della Svizzera Italiana, Via Giuseppe Buffi 13, 6900, Lugano, Switzerland. .,Department of Cardiac Surgery, Istituto Cardiocentro Ticino, EOC, Lugano, Switzerland.
| | - Geni Singjeli
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, EOC, Lugano, Switzerland
| | - Stefanos Demertzis
- Faculty of Biomedical Sciences, Università Della Svizzera Italiana, Via Giuseppe Buffi 13, 6900, Lugano, Switzerland.,Department of Cardiac Surgery, Istituto Cardiocentro Ticino, EOC, Lugano, Switzerland
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8
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Puthettu M, Vandenberghe S, Bagnato P, Gallo M, Demertzis S. Gaseous Microemboli in the Cardiopulmonary Bypass Circuit: Presentation of a Systematic Data Collection Protocol Applied at Istituto Cardiocentro Ticino. Cureus 2022; 14:e22310. [PMID: 35350483 PMCID: PMC8933722 DOI: 10.7759/cureus.22310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2022] [Indexed: 11/05/2022] Open
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9
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Puthettu M, Vandenberghe S, Demertzis S. Development of a Gastight Thoracotomy Model for Investigation of Carbon Dioxide Field-Flooding Efficacy. Cureus 2022; 14:e21099. [PMID: 35165558 PMCID: PMC8830381 DOI: 10.7759/cureus.21099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2022] [Indexed: 11/21/2022] Open
Abstract
Carbon dioxide (CO2) field-flooding during cardiac surgery is a prevention technique to avoid blood-air contact and subsequent embolization. Although it was first used more than 60 years ago, there is still some perplexity around its efficacy, mainly because the gas is invisible and air embolization is difficult to quantify. An accurate assessment of field-flooding can, therefore, best be performed in models where various methods can be tried in a controlled environment and evaluated with industrial-grade sensors. Multiple options are available for anatomically correct models that reproduce a sternotomy situation, but models for minimally invasive cardiac surgery are expensive and normally meant for training of surgical techniques where only the top side of the model is important. We created a low-cost and “home-made” gastight mini-thoracotomy model with internal organs and left atrial incision to investigate CO2 insufflation in a simulated minimally invasive mitral valve surgery. The model was validated with CO2 field-flooding tests with a commercial diffuser, while three sensors continuously registered the local concentration of CO2 gas.
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Vu T, Smith JA. An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery. Front Psychiatry 2022; 13:884907. [PMID: 35782418 PMCID: PMC9240195 DOI: 10.3389/fpsyt.2022.884907] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 05/23/2022] [Indexed: 12/14/2022] Open
Abstract
Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015-present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.
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Affiliation(s)
- Tony Vu
- Department of Cardiothoracic Surgery, Monash Health, Melbourne, VIC, Australia.,Department of Surgery, School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia
| | - Julian A Smith
- Department of Cardiothoracic Surgery, Monash Health, Melbourne, VIC, Australia.,Department of Surgery, School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia
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