Carbon Dioxide Insufflation During Cardiac Surgery: A Meta-analysis of Randomized Controlled Trials

CO2 delivery techniques in mini-sternotomy surgery and neurological events: a multicentric study

BACKGROUND

The impact of air bubbles into the cerebral circulation after open heart surgery has been a topic of discussion since the introduction of the heart-lung machine. The aim of the study was to evaluate whether the use of a dedicated commercial sponge diffuser is better than a custom-made narrow section cannula or the absence of CO2 in preventing neurological events after aortic valve replacement via J mini-sternotomy.

METHODS

Three cohorts of J-shaped mini-sternotomy performed at three different centers were prospectively compared: CO2 supplied via sponge diffuser, CO2 supplied via cannula, and no CO2 supply. Propensity matching was used to obtain comparable groups. The primary endpoints were postoperative stroke, transitory ischemic attack, convulsions, and dizziness. Secondary endpoints were 30-day mortality, duration of mechanical ventilation, and intensive care unit length of stay.

RESULTS

275 patients were enrolled in the study. After propensity matching, the sponge diffuser cohort had a significantly lower duration of mechanical ventilation (P < 0.001) and 30-day mortality (P = 0.05) when compared to the cannula cohort and the no-CO2 cohort, a lower incidence of all neurological events (P = 0.03) and dizziness (P = 0.05) when compare to the no-CO2 cohort, and a lower intensive care unit length of stay when compared to the cannula cohort (P = 0.001).

CONCLUSIONS

The sponge diffuser used to deliver the CO2 into the surgical field during aortic valve replacement via J mini-sternotomy has been demonstrated to guarantee better neurological outcomes compared to a custom-made narrow section cannula or the absence of CO2.

Totally Endoscopic Atrial Septal Defect Repair on Beating Heart: Clinical Outcome and Single-Surgeon Learning Curve Experience

OBJECTIVE

To evaluate the safety and efficacy of the Hanoi ASD procedure, which is totally endoscopic surgery for atrial septal defect (ASD) repair on beating heart. In addition, the present study also aimed to analyze the learning curve for this procedure.

METHODS

From May 2016 to February 2023, 198 consecutive ASD patients weighing ≥20 kg were enrolled in the retrospective study. The Hanoi ASD procedure includes (1) unilateral or bilateral femoral arterial cannulation; (2) two or three 5 mm trocars and a 15 mm port; (3) ASD repair on beating heart, preventing air embolism with CO2 insufflation and keeping the left atrium full of blood; and (4) not snaring the inferior vena cava. Cumulative sum (CUSUM) analysis was used to evaluate the cardiopulmonary bypass (CPB) and operation time learning curves. Variables among the learning curve phases were compared.

RESULTS

The CPB and operation times were 90 (72 to 115) min and 180 (150 to 220) min, respectively. Total drainage volume was 190 (120 to 290) mL. No endoscopic failure or major complications were complications were excluding factors causing bias, the CUSUMCPBtime analysis for the remaining 131 patients included 3 phases. Phase 1 was the initial learning period (cases 1 to 34), phase 2 represented the technical competence period (cases 35 to 54), and phase 3 was the challenging period (cases 55 to 131).

CONCLUSIONS

The Hanoi ASD procedure is safe and feasible for repairing ASD in patients weighing ≥20 kg. According to the learning curve analysis, 34 cases were required to achieve technical efficiency, and 54 cases were required to address highly challenging cases.

Efficacy and safety of carbon dioxide insufflation for brain protection for patients undergoing planned left-sided open heart valve surgery: protocol for a multicentre, placebo-controlled, blinded, randomised controlled trial (the CO2 Study)

INTRODUCTION

Brain injury is common following open heart valve surgery. Carbon dioxide insufflation (CDI) has been proposed to reduce the incidence of brain injury by reducing the number of air microemboli entering the bloodstream in surgery. The CO2 Study will evaluate the efficacy and safety of CDI in patients undergoing planned left-sided open heart valve surgery.

METHODS AND ANALYSIS

The CO2 Study is a multicentre, blinded, placebo-controlled, randomised controlled trial. Seven-hundred and four patients aged 50 years and over undergoing planned left-sided heart valve surgery will be recruited to the study, from at least eight UK National Health Service hospitals, and randomised in a 1:1 ratio to receive CDI or medical air insufflation (placebo) in addition to standard de-airing. Insufflation will be delivered at a flow rate of 5 L/min from before the initiation of cardiopulmonary bypass until 10 min after cardiopulmonary bypass weaning. Participants will be followed up until 3 months post-surgery. The primary outcome is acute ischaemic brain injury within 10 days post-surgery based on new brain lesions identified with diffusion-weighted MRI or clinical evidence of permanent brain injury according to the current definition of stroke.

ETHICS AND DISSEMINATION

The study was approved by the East Midlands-Nottingham 2 Research Ethics Committee in June 2020 and the Medicines and Healthcare products Regulatory Agency in May 2020. All participants will provide written informed consent prior to undertaking any study assessments. Consent will be obtained by the principal investigator or a delegated member of the research team who has been trained in the study and undergone Good Clinical Practice training. Results will be disseminated through peer-reviewed publications and presentations at national and international meetings. Study participants will be informed of results through study notifications and patient organisations.

TRIAL REGISTRATION NUMBER

ISRCTN30671536.

Warm humidified CO2 insufflation improves pericardial integrity for cardiac surgery: a randomized control study

BACKGROUND

Flooding the surgical field with dry cold CO<inf>2</inf> during open-chamber cardiac surgery has been used to mitigate air entrainment into the systemic circulation. However, exposing epithelial surfaces to cold, dry gas causes tissue desiccation. This randomized controlled study was designed to investigate whether the use of humidified warm CO<inf>2</inf> insufflation into the cardiac cavity could reduce pericardial tissue damage and the incidence of micro-emboli when compared to dry cold CO<inf>2</inf> insufflation.

METHODS

Forty adult patients requiring elective open-chamber cardiac surgery were randomized to have either dry cold CO<inf>2</inf> insufflation via a standard catheter or humidified warm CO<inf>2</inf> insufflation via the HumiGard device (Fisher & Paykel Healthcare, Panmure, Auckland, New Zealand). The primary endpoint was biopsied pericardial tissue damage, assessed using electron microscopy. We assessed the percentage of microvilli and mesothelial damage, using a damage severity score (DSS) system. We compared the proportion of patients who had less damage, defined as DSS<2. Secondary endpoints included the severity of micro-emboli, by visual assessment of bubble load on transesophageal echocardiogram; lowest near infrared spectroscopy; total de-airing time; highest cardio-pulmonary bypass sweep speed; hospital length of stay and complications.

RESULTS

A higher proportion of patients in the humidified warm CO<inf>2</inf> group displayed conserved microvilli (47% vs. 11%, P=0.03) and preserved mesothelium (42% vs. 5%, P=0.02) compared to the control group. There were no differences in the secondary outcomes.

CONCLUSIONS

Humidified warm CO<inf>2</inf> insufflation significantly reduced pericardial epithelial damage when compared to dry cold CO<inf>2</inf> insufflation in open-chamber cardiac surgery. Further studies are warranted to investigate its potential clinical benefits.

Considerations for Reduction of Risk of Perioperative Stroke in Adult Patients Undergoing Cardiac and Thoracic Aortic Operations: A Scientific Statement From the American Heart Association

Perioperative stroke is one of the most severe and feared complications of cardiac surgery. Based on the timing of onset and detection, perioperative stroke can be classified as intraoperative or postoperative. The pathogenesis of perioperative stroke is multifactorial, which makes prediction and prevention challenging. However, information on its incidence, mechanisms, diagnosis, and treatment can be helpful in minimizing the perioperative neurological risk for individual patients. We herein provide suggestions on preoperative, intraoperative, and postoperative strategies aimed at reducing the risk of perioperative stroke and at improving the outcomes of patients who experience a perioperative stroke.