Minimally invasive extracorporeal circulation versus conventional cardiopulmonary bypass in patients undergoing cardiac surgery (MiECS): Rationale and design of a multicentre randomised trial.

INTRODUCTION: The ultimate answer to the question whether minimal invasive extracorporeal circulation (MiECC) represents the optimal perfusion technique in contemporary clinical practice remains elusive. The present study is a real-world study that focuses on specific perfusion-related clinical outcomes after cardiac surgery that could potentially be favourably affected by MiECC and thereby influence the future clinical practice. METHODS: The MiECS study is an international, multi-centre, two-arm randomized controlled trial. Patients undergoing elective or urgent coronary artery bypass grafting (CABG), aortic valve replacement (AVR) or combined procedure (CABG + AVR) using extracorporeal circulation will be randomized to MiECC or contemporary conventional cardiopulmonary bypass (cCPB). Use of optimized conventional circuits as controls is acceptable. The study design includes a range of features to prevent bias and is registered at clinicaltrials.gov (NCT05487612). RESULTS: The primary outcome is a composite of postoperative serious adverse events that could be related to perfusion technique occurring up to 30 days postoperatively. Secondary outcomes include use of blood products, ICU and hospital length of stay (30 days) as well as health-related quality of life (30 and 90 days). CONCLUSIONS: The MiECS trial has been designed to overcome perceived limitation of previous trials of MiECC. Results of the proposed study could affect current perfusion practice towards advancement of patient care.

Conventional versus minimally invasive extra-corporeal circulation in patients undergoing cardiac surgery: A randomized controlled trial (COMICS).

INTRODUCTION: The trial hypothesized that minimally invasive extra-corporeal circulation (MiECC) reduces the risk of serious adverse events (SAEs) after cardiac surgery operations requiring extra-corporeal circulation without circulatory arrest. METHODS: This is a multicentre, international randomized controlled trial across fourteen cardiac surgery centres including patients aged ≥18 and <85 years undergoing elective or urgent isolated coronary artery bypass grafting (CABG), isolated aortic valve replacement (AVR) surgery, or CABG + AVR surgery. Participants were randomized to MiECC or conventional extra-corporeal circulation (CECC), stratified by centre and operation. The primary outcome was a composite of 12 post-operative SAEs up to 30 days after surgery, the risk of which MiECC was hypothesized to reduce. Secondary outcomes comprised: other SAEs; all-cause mortality; transfusion of blood products; time to discharge from intensive care and hospital; health-related quality-of-life. Analyses were performed on a modified intention-to-treat basis. RESULTS: The trial terminated early due to the COVID-19 pandemic; 1071 participants (896 isolated CABG, 97 isolated AVR, 69 CABG + AVR) with median age 66 years and median EuroSCORE II 1.24 were randomized (535 to MiECC, 536 to CECC). Twenty-six participants withdrew after randomization, 22 before and four after intervention. Fifty of 517 (9.7%) randomized to MiECC and 69/522 (13.2%) randomized to CECC group experienced the primary outcome (risk ratio = 0.732, 95% confidence interval (95% CI) = 0.556 to 0.962, p = 0.025). The risk of any SAE not contributing to the primary outcome was similarly reduced (risk ratio = 0.791, 95% CI 0.530 to 1.179, p = 0.250). CONCLUSIONS: MiECC reduces the relative risk of primary outcome events by about 25%. The risk of other SAEs was similarly reduced. Because the trial terminated early without achieving the target sample size, these potential benefits of MiECC are uncertain.

A Prospective Study of the Effect of Gastroduodenal Artery Reconstruction on Duodenal Oxygenation and Enzyme Content After Pancreas Transplantation.

BACKGROUND: Whole pancreas transplantation provides durable glycemic control and can improve survival rate; however, it can carry an increased risk of surgical complications. One devastating complication is a duodenal leak at the site of enteroenteric anastomosis. The gastroduodenal artery (GDA) supplies blood to the donor duodenum and pancreas but is commonly ligated during procurement. Since we have not had expressive changes in pancreatic back table surgical techniques in the recent decades, we hypothesized whether back table GDA reconstruction, improving perfusion of the donor duodenum and head of the pancreas, could lead to fewer surgical complications in simultaneous pancreas-kidney (SPK) transplants. MATERIAL AND METHODS: Between 2017 and 2021, we evaluated demographic information, postoperative complications, intraoperative donor duodenum, recipient bowel O2 tissue saturation, and patient morbidity through the Comprehensive Complication Index (CCI®). RESULTS: A total of 26 patients were included: 13 underwent GDA reconstruction (GDA-R), and 13 had GDA ligation (GDA-L). There were no pancreatic leaks in the GR group compared to 38% (5/13) in the GDA-L group (p = 0.03913). Intraoperative tissue oxygen saturation was higher in the GDA-R group than in the GDA-L (95.18 vs.76.88%, p < 0,001). We observed an increase in transfusion rate in GDA-R (p < 0.05), which did not result in a higher rate of exploration (p = 0.38). CCI® patient morbidity was also significantly lower in the GDA-R group (s < 0.05). CONCLUSIONS: This study identified improved intraoperative duodenal tissue oxygen saturation in the GDA-R group with an associated reduction in pancreatic leaks and CCI® morbidity risk. A larger prospective multicenter study comparing the two methods is warranted.

Incidence, predictors and vascular sequelae of distal limb ischemia in minimally invasive cardiac surgery with femoral artery cannulation: an observational cohort study.

Literature regarding monitoring and consequences of distal limb ischemia due to femoral artery cannulation for Minimally Invasive Cardiac Surgery (MICS) remains limited. The primary objective was to determine its incidence, defined as a ≥ 15% difference in regional Oxygen Saturation (rSO2) lasting ≥ four consecutive minutes between the cannulated and non-cannulated limb. The secondary objectives included: determination of distal limb ischemia, defined as a Tissue Oxygenation Index (TOI) < 50% in the cannulated limb, identification of predictors for distal limb ischemia, determination of a possible association of NIRS-diagnosed ischemia with acute kidney injury, and the need for vascular surgery up to six months after cardiac surgery. A prospective, observational cohort study with blinded rSO2-measurements to prevent intraoperative clinical decision-making. A single-center, community-hospital, clinical study. All consecutive patients ≥ 18 years old, and scheduled for predefined MICS. Patients underwent MICS with bilateral calf muscle rSO2-measurements conducted by Near-Infrared Spectroscopy (NIRS). In total 75/280 patients (26.79%) experienced distal limb ischemia according to the primary objective, while 18/280 patients (6.42%) experienced distal limb ischemia according to the secondary objective. Multivariate logistic regression showed younger age to be an independent predictor for distal limb ischemia (p = 0.003). None of the patients who suffered intraoperative ischemia required vascular surgery within the follow-up period. The incidence of NIRS-diagnosed ischemia varied from 6.4% to 26.8% depending on the used criteria. Short and long-term vascular sequelae, however, are limited and not intraoperative ischemia related. The added value of intraoperative distal limb NIRS monitoring for vascular reasons seems limited. Future research on femoral artery cannulation in MICS should shift focus to other outcome parameters such as acute kidney injury, postoperative pain or paresthesias.

2021 MiECTiS focused update on the 2016 position paper for the use of minimal invasive extracorporeal circulation in cardiac surgery.

The landmark 2016 Minimal Invasive Extracorporeal Technologies International Society (MiECTiS) position paper promoted the creation of a common language between cardiac surgeons, anesthesiologists and perfusionists which led to the development of a stable framework that paved the way for the advancement of minimal invasive perfusion and related technologies. The current expert consensus document offers an update in areas for which new evidence has emerged. In the light of published literature, modular minimal invasive extracorporeal circulation (MiECC) has been established as a safe and effective perfusion technique that increases biocompatibility and ultimately ensures perfusion safety in all adult cardiac surgical procedures, including re-operations, aortic arch and emergency surgery. Moreover, it was recognized that incorporation of MiECC strategies advances minimal invasive cardiac surgery (MICS) by combining reduced surgical trauma with minimal physiologic derangements. Minimal Invasive Extracorporeal Technologies International Society considers MiECC as a physiologically-based multidisciplinary strategy for performing cardiac surgery that is associated with significant evidence-based clinical benefit that has accrued over the years. Widespread adoption of this technology is thus strongly advocated to obtain additional healthcare benefit while advancing patient care.

Automated Nerve Monitoring in Shoulder Arthroplasty: A Prospective Randomized Controlled Study.

BACKGROUND: Evoked potential monitoring is believed to prevent neurologic injury in various surgical settings; however, its clinical effect has not been scrutinized. It was hypothesized that an automated nerve monitor can minimize intraoperative nerve injury and thereby improve clinical outcomes in patients undergoing shoulder arthroplasty. METHODS: A prospective, blinded, parallel group, superiority design, single-center, randomized controlled study was conducted. Study participants were equally randomized into either the automated nerve-monitored or the blinded monitored groups. The primary outcome was intraoperative nerve injury burden as assessed by the cumulative duration of nerve alerts. Secondary outcomes were neurologic deficits and functional scores of the operative arm, and the quality of life index (Euro Quality of life-5 domain-5 level score) at postoperative weeks 2, 6, and 12. RESULTS: From September 2018 to July 2019, 213 patients were screened, of whom 200 were randomized. There was no statistically significant difference in the duration of nerve alerts between the automated nerve-monitored and control groups (median [25th, 75th interquartile range]: 1 [0, 18] and 5 [0, 26.5]; Hodges-Lehman difference [95% CI]: 0 [0 to 1] min; P = 0.526). There were no statistically significant differences in secondary outcomes between groups. However, in the ancillary analysis, there were reductions in neurologic deficits and improvements in quality of life index occurring in both groups over the course of the study period. CONCLUSIONS: Protection from nerve injury is a shared responsibility between surgeons and anesthesiologists. Although a progressive improvement of clinical outcomes were observed over the course of the study in both groups as a consequence of the real-time feedback provided by the automated nerve monitor, this trial did not demonstrate that automated nerve monitoring by itself changes important clinical outcomes compared with no monitoring.

A novel approach of using brachial plexus blockade as an experimental model for diagnosis of intraoperative nerve dysfunction with somatosensory evoked potentials: a blinded proof-of-concept study.

PURPOSE: Intraoperative nerve dysfunction has been difficult to investigate because of its rarity and unpredictable occurrence. The diagnostic test attributes of nerve function monitors have not been clearly defined. This proof-of-concept study aimed to assess the feasibility of using brachial plexus blockade (BPB) in awake patients as an experimental model for nerve dysfunction to characterize the diagnostic test attributes of somatosensory evoked potentials (SSEPs). METHODS: We obtained baseline SSEPs and neurologic function in patients and subsequently placed BPBs (experimental model) to generate progressive states of nerve dysfunction. We monitored SSEP changes (index test) and neurologic symptoms (reference standard) simultaneously during the onset of BPB to determine the temporal relationships and diagnostic test attributes of SSEPs. RESULTS: Brachial plexus blockade produced differential motor and sensory dysfunction that allowed simultaneous clinical and neurophysiologic assessment. One hundred and fifty-seven pairs of multiple data points from 14 patients were included for final analysis. The onset of abnormal SSEP signals almost always preceded the onset of neurologic symptoms. The sensitivities and specificities of SSEP to detect the impairment of power (motor rating score ≤ 4/5), cold sensation, and two-point discrimination were 100% and 67%, 99% and 55%, and 100% and 46%, respectively. CONCLUSION: This study found that BPB can produce sufficient differential nerve dysfunction to allow adequate evaluation of the diagnostic test attributes of SSEPs as a nerve monitor. The results of this study may stimulate further work on refining intraoperative nerve dysfunction models and diagnostic nerve function monitors. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03409536); registered 24 January 2018.

RéSUMé: OBJECTIF: La dysfonction nerveuse peropératoire est difficile à étudier en raison de sa rareté et de son imprévisibilité. Les attributs d'un test diagnostique des moniteurs de la fonction nerveuse n'ont pas été clairement définis. Cette étude de démonstration de faisabilité visait à évaluer la faisabilité de l'utilisation d'un bloc du plexus brachial (BPB) chez des patients éveillés comme modèle expérimental de la dysfonction nerveuse afin de caractériser les attributs de test diagnostique des potentiels évoqués somesthésiques (PES). MéTHODE: Nous avons enregistré les PES et la fonction neurologique de base des patients, puis administré des BPB (modèle expérimental) pour générer des états progressifs de dysfonction nerveuse. Nous avons surveillé simultanément les changements des PES (test pour déterminer l'indicateur) et les symptômes neurologiques (norme de référence) pendant l'évolution du BPB afin de déterminer les relations temporelles et les attributs de test diagnostique des PES. RéSULTATS: Le bloc du plexus brachial a produit une dysfonction motrice et sensorielle différentielle qui nous a permis de procéder à une évaluation clinique et neurophysiologique simultanée. Cent cinquante-sept paires de points de données multiples issues de 14 patients ont été incluses pour l'analyse finale. L'apparition de signaux de PES anormaux a presque toujours précédé l'apparition de symptômes neurologiques. Les sensibilités et les spécificités des PES pour détecter la perte de force (score moteur ≤ 4/5), la sensation de froid et la discrimination à deux points étaient de 100 % et 67 %, 99 % et 55 %, et 100 % et 46 %, respectivement. CONCLUSION: Cette étude a constaté que le bloc du plexus brachial peut produire une dysfonction nerveuse différentielle suffisante pour permettre l'évaluation adéquate des attributs de test diagnostique des PES en tant que moniteur nerveux. Les résultats de cette étude pourraient motiver d'autres travaux sur l'amélioration des modèles de dysfonction nerveuse peropératoire et des moniteurs diagnostiques de la fonction nerveuse. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03409536); enregistrée le 24 janvier 2018.

Feasibility of studying the association between intraoperative regional cerebral oxygen saturation and postoperative functional decline (ReFUNCTION): a pilot sub-study of NeuroVISION-Cardiac Surgery.

PURPOSE: Function describes an individual's ability to perform everyday activities. In the context of cardiac surgery, functional changes quantify the effect of surgery on one's day-to-day life. Decreases in regional cerebral oxygen saturation (rScO2) measured using near-infrared spectroscopy (NIRS) has been associated with postoperative cognitive decline but its relationship with function has not been studied. We sought to determine the feasibility of conducting a large observational study examining the relationship between decreases in rScO2 during cardiac surgery and postoperative functional decline. METHODS: We undertook a single-centre, pilot sub-study of the NeuroVISION-Cardiac Surgery pilot study, which included adults undergoing isolated coronary artery bypass grafting on cardiopulmonary bypass; all patients enrolled in NeuroVISION-Cardiac Surgery were included. Function was evaluated at baseline, 30 days, and three months using the Standardized Assessment of Global activities in the Elderly (SAGE) scale. Blinded NIRS monitors were affixed for the duration of surgery. Our feasibility outcomes were to recruit one patient per week, obtain complete NIRS data in ≥ 90%, obtain SAGE at all time-points in ≥ 90%, and determine the time required for NIRS data to be transcribed into case report forms. RESULTS: 49/50 patients enrolled in NeuroVISION-Cardiac Surgery were recruited over 48 weeks (1.02 patients/week). Of the 49 included patients, 49 (100%) had complete NIRS data and 44 (90%) had complete SAGE data. The time required for NIRS data collection was a mean (standard deviation) of 5.5 (1.8) min per patient. CONCLUSION: This pilot study shows the feasibility of conducting a large observational study examining the relationship between decreases in cerebral saturation during cardiac surgery and postoperative functional decline. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT04241289); registered 27 January 2020.

RéSUMé: OBJECTIF : La capacité fonctionnelle constitue la capacité d'une personne à accomplir des activités quotidiennes. Dans le contexte d'une chirurgie cardiaque, les changements fonctionnels permettent de quantifier l'effet de la chirurgie sur le quotidien des individus. Les baisses de la saturation en oxygène cérébral régional (rScO2) mesurées à l'aide de la spectroscopie proche infrarouge (NIRS) ont été associées à un déclin cognitif postopératoire, mais leur relation par rapport à la capacité fonctionnelle n'a pas été étudiée. Nous avons tenté de déterminer s'il était possible de réaliser une vaste étude observationnelle examinant la relation entre les baisses de rScO2 pendant une chirurgie cardiaque et le déclin fonctionnel postopératoire. MéTHODE : Nous avons entrepris une sous-étude pilote monocentrique de l'étude pilote NeuroVISION-Cardiac Surgery, qui incluait des adultes subissant une chirurgie de pontage aortocoronarien sous circulation extracorporelle; tous les patients recrutés dans l'étude NeuroVISION-Cardiac Surgery ont été inclus dans ce volet. La capacité fonctionnelle a été évaluée avant l'opération, puis à 30 jours et trois mois à l'aide de l'échelle SAGE (Standardized Assessment of Global activities in the Elderly, soit Évaluation standardisée de la fonction globale chez la personne âgée). Des moniteurs de NIRS étaient installés pour toute la durée de la chirurgie sans que les valeurs ne soient connues de l'équipe traitante. Nos critères de faisabilité consistaient à recruter un patient par semaine, obtenir des données de NIRS complètes pour ≥ 90 % des patients, obtenir des données de SAGE pour tous les points dans le temps pour ≥ 90 % des patients, et déterminer le temps nécessaire à retranscrire les données de NIRS dans les formulaires d'étude de cas. RéSULTATS : Au total, 49/50 patients recrutés dans l'étude NeuroVISION-Cardiac Surgery ont été recrutés sur une période de 48 semaines (1,02 patients/semaine). Parmi les 49 patients inclus, les données de NIRS ont été obtenues pour 49 (100 %) patients et les données de SAGE pour 44 (90 %) patients. Le temps nécessaire à la collecte de données de NIRS était en moyenne (écart type) de 5,5 (1,8) min par patient. CONCLUSION : L'étude pilote a démontré la faisabilité d'une vaste étude observationnelle examinant la relation entre les baisses de la saturation cérébrale pendant la chirurgie cardiaque et le déclin fonctionnel postopératoire. ENREGISTREMENT DE L'éTUDE : www.clinicaltrials.gov (NCT04241289); enregistrée le 27 janvier 2020.

Perioperative Peripheral Nerve Injury After General Anesthesia: A Qualitative Systematic Review.

Perioperative peripheral nerve injury (PNI) is a well-recognized complication of general anesthesia that continues to result in patient disability and malpractice claims. However, the multifactorial etiology of PNI is often not appreciated in malpractice claims given that most PNI is alleged to be due to errors in patient positioning. New advances in monitoring may aid anesthesiologists in the early detection of PNI. This article reviews recent studies of perioperative PNI after general anesthesia and discusses the epidemiology and potential mechanisms of injury and preventive measures. We performed a systematic literature search, reviewed the available evidence, and identified areas for further investigation. We also reviewed perioperative PNI in the Anesthesia Closed Claims Project database for adverse events from 1990 to 2013. The incidence of perioperative PNI after general anesthesia varies considerably depending on the type of surgical procedure, the age and risk factors of the patient population, and whether the detection was made retrospectively or prospectively. Taken together, studies suggest that the incidence in a general population of surgical patients undergoing all types of procedures is <1%, with higher incidence in cardiac, neurosurgery, and some orthopedic procedures. PNI represent 12% of general anesthesia malpractice claims since 1990, with injuries to the brachial plexus and ulnar nerves representing two-thirds of PNI claims. The causes of perioperative PNI after general anesthesia are likely multifactorial, resulting in a "difficult to predict and prevent" phenomenon. Nearly half of the PNI closed claims did not have an obvious etiology, and most (91%) were associated with appropriate anesthetic care. Future studies should focus on the interaction between different mechanisms of insult, severity and duration of injury, and underlying neuronal reserves. Recent automated detection technology in neuromonitoring with somatosensory evoked potentials may increase the ability to identify at-risk patients and individualize patient management.

A Novel Automated Somatosensory Evoked Potential (SSEP) Monitoring Device for Detection of Intraoperative Peripheral Nerve Injury in Cardiac Surgery: A Clinical Feasibility Study.

OBJECTIVE: Peripheral nerve injury (PNI) is a common and potentially devastating complication in cardiac surgery. Somatosensory evoked potential (SSEP) monitoring is one of the modalities for PNI; however, its application is limited by complicated logistics. This study aimed to assess the feasibility of using a novel, automated SSEP device (EPAD; SafeOp Surgical, Hunt Valley, MD) for detection of intraoperative PNI during cardiac surgery. DESIGN: Prospective, observational study. SETTING: Single university hospital. PARTICIPANTS: Cardiac surgical patients. INTERVENTIONS: After Ethics Board approval and written consent, study participants were monitored using the EPAD automated SSEP device during cardiac surgery. All patients with prolonged and abnormal SSEP changes were evaluated postoperatively, and if they were symptomatic, they were referred for further nerve conduction and electromyographic assessment. MEASUREMENTS AND MAIN RESULTS: Of the 43 patients who consented to study inclusion, 33 were monitored successfully. With increasing clinical experience the authors encountered minimal technical issues, and satisfactory signals were obtained in most patients. Abnormal SSEP signal changes, which were encountered in 5 (15.2%) patients, were interpreted as impending PNI; 3 patients experienced prolonged signal changes (>1 h), and 2 (6.1%) of these developed symptomatic peripheral neuropathy that was confirmed with nerve conduction studies. CONCLUSIONS: The EPAD automated SSEP device is a viable option for detecting PNI during cardiac surgery. A high incidence of intraoperative peripheral nerve compromise and a 6.1% incidence of postoperative peripheral neuropathy were observed. This study reports the clinical feasibility of using the EPAD automated SSEP device; additional studies are required to evaluate the diagnostic test accuracy and the outcome benefit of routine SSEP monitoring in cardiac surgical patients.

Comparison of isoflurane and sevoflurane in cardiac surgery: a randomized non-inferiority comparative effectiveness trial.

PURPOSE: Volatile anesthetics possess cardioprotective properties, but it is unknown if the cardioprotective effects extend equally to all members of the class. Although sevoflurane is a relatively newer anesthetic than isoflurane, its introduction into practice was not preceded by a head-to-head comparison with isoflurane in a trial focusing on clinically important outcomes. Our objective was to determine whether sevoflurane was non-inferior to isoflurane on a clinically important primary outcome in a heterogeneous group of adults undergoing cardiac surgery. METHODS: This was a pragmatic randomized non-inferiority comparative effectiveness clinical trial in 464 adults having coronary artery bypass graft and/or single valve surgery during November 2011 to March 2014. The intervention was maintenance of anesthesia with sevoflurane (n = 231) or isoflurane (n = 233) administered at a dose of 0.5-2.0 MAC throughout the entire operation. All caregivers were blinded except for the anesthesiologist and perfusionist. The primary outcome was a composite of intensive care unit (ICU) length of stay ≥ 48 hr and all-cause 30-day mortality. We hypothesized that sevoflurane would be non-inferior to isoflurane (non-inferiority margin < 10% based on an expected event rate of 25%). Secondary outcomes included prolonged ICU stay, 30- and 365-day all-cause mortality, inotrope or vasopressor usage, new-onset hemodialysis or atrial fibrillation, stroke, and readmission to the ICU. RESULTS: No losses to follow-up occurred. The primary outcome occurred in 25% of sevoflurane patients and 30% of isoflurane patients (absolute difference, -5.4%; one-sided 95% confidence interval, 1.4), thus non-inferiority was declared. Sevoflurane was not superior to isoflurane for the primary outcome (P = 0.21) or for any secondary outcomes. CONCLUSION: Sevoflurane is non-inferior to isoflurane on a composite outcome of prolonged ICU stay and all-cause 30-day mortality. Sevoflurane is not superior to isoflurane on any other of the clinically important outcomes. This trial was registered at clinicaltrials.gov; NCT01477151.

RéSUMé: OBJECTIF: Les agents anesthésiques volatils possèdent des propriétés cardioprotectrices, mais nous ne savons pas si ces effets cardioprotecteurs sont équivalents pour tous les agents de cette classe. Bien que le sévoflurane soit un anesthésique plus récent que l'isoflurane, son introduction dans notre pratique n'a pas été précédée par une comparaison directe à l'isoflurane dans une étude s'intéressant à d'importants critères d'évaluation cliniques. Notre objectif était de déterminer si le sévoflurane était non inférieur à l'isoflurane en relation à un critère d'évaluation principal important d'un point de vue clinique dans un groupe hétérogène d'adultes subissant une chirurgie cardiaque. MéTHODE: Nous avons réalisé une étude clinique randomisée et pragmatique d'efficacité comparative et de non-infériorité auprès de 464 adultes subissant des pontages coronariens et/ou une chirurgie valvulaire unique entre novembre 2011 et mars 2014. L'intervention consistait en le maintien de l'anesthésie à l'aide de sévoflurane (n = 231) ou d'isoflurane (n = 233) administré à une dose de 0,5-2,0 MAC tout au long de l'opération. Aucun intervenant ne connaissait l'agent utilisé, à l'exception de l'anesthésiologiste et du perfusionniste. Le critère d'évaluation principal était une composée de la durée de séjour à l'unité de soins intensifs (USI) ≥ 48 h et de la mortalité, toutes causes confondues, à 30 jours. Nous avons émis l'hypothèse que le sévoflurane ne serait pas inférieur à l'isoflurane (marge de non-infériorité < 10 % sur la base d'un taux de complications attendu de 25 %). Les critères d'évaluation secondaires comprenaient un séjour prolongé à l'USI, la mortalité toutes causes confondues à 30 et à 365 jours, l'utilisation d'inotropes ou de vasopresseurs, une hémodialyse ou une fibrillation auriculaire nouvelles, un accident vasculaire cérébral et une réadmission à l'USI. RéSULTATS: Nous n'avons perdu aucun patient au suivi. Le critère d'évaluation principal est survenu chez 25 % des patients ayant reçu du sévoflurane et 30 % des patients ayant reçu de l'isoflurane (différence absolue, −5,4 %; intervalle de confiance unilatéral 95 %, 1,4): la non-infériorité a donc été déclarée. Le sévoflurane n'était pas supérieur à l'isoflurane en ce qui touchait au critère d'évaluation principal (P = 0,21) ou aux critères d'évaluation secondaires. CONCLUSION: Le sévoflurane n'est pas inférieur à l'isoflurane selon un critère d'évaluation composé d'une durée de séjour prolongée à l'USI et de la mortalité toutes causes confondues à 30 jours. Le sévoflurane n'est pas supérieur à l'isoflurane en ce qui touche à n'importe quel autre critère clinique important. Cette étude a été enregistrée au ClinicalTrials.gov, numéro NCT01477151.

Tissue microcirculation measured by vascular occlusion test during anesthesia induction.

Tissue microcirculation measured by vascular occlusion test is impaired during septic shock. However, it has not been investigated extensively during anesthesia induction. The aim of the study is to evaluate tissue microcirculation during anesthesia induction. We hypothesized that during anesthesia induction, tissue microcirculation measured by vascular occlusion test might be enhanced with peripheral vasodilation during anesthesia induction. We conducted a prospective observational study of 50 adult patients undergoing cardiac surgery. During anesthesia induction, we measured and analyzed tissue oxygen saturation, vascular occlusion test, cerebral oximetry, forearm-minus-fingertip skin temperature gradients and hemodynamic data in order to evaluate microcirculation as related to alterations in peripheral vasodilation as reflected by increased Tforearm-finger thermal gradients. During anesthesia induction, recovery slope during vascular occlusion test and cerebral oxygen saturation increased from 4.0 (1.5) to 4.7 (1.3) % s(-1) (p = 0.02) and 64.0 (10.2) to 74.2 (9.2) % (p < 0.001), respectively. Forearm-minus-fingertip skin temperature gradients decreased from 1.9 (2.9) to -1.4 (2.2) °C (p < 0.001). There was an inverse correlation between changes in the skin temperature gradients and changes in cerebral oximetry (r = 0.33; p = 0.02). During anesthesia induction, blood pressure and forearm-minus-fingertip skin temperature gradients decrease while cerebral oximetry and vascular occlusion test recovery slope increase. These findings suggest that anesthesia induction increases tissue microcirculation with peripheral vasodilation.

Microvascular reactivity and clinical outcomes in cardiac surgery.

INTRODUCTION: Microvascular reactivity is decreased in patients with septic shock; this is associated with worse clinical outcomes. The objectives of the present study were to investigate microvascular reactivity in cardiac surgery patients and to assess any association with clinical outcomes. METHODS: We retrospectively analyzed a prospectively collected registry. In total, 254 consecutive adult patients undergoing cardiac and thoracic aortic surgeries from January 2013 through May 2014 were analyzed. We performed a vascular occlusion test (VOT) by using near-infrared spectroscopy to measure microvascular reactivity. VOT was performed three times per patient: prior to the induction of anesthesia, at the end of surgery, and on postoperative day 1. The primary endpoint was a composite of major adverse complications, including death, myocardial infarction, acute kidney injury, acute respiratory distress syndrome, and persistent cardiogenic shock. RESULTS: VOT recovery slope decreased during the surgery. VOT recovery slope on postoperative day 1 was significantly lower in patients with composite complications than those without (3.1 ± 1.6 versus 4.0 ± 1.5%/s, P = 0.001), although conventional hemodynamic values, such as cardiac output and blood pressure, did not differ between the groups. On multivariable regression and linear analyses, low VOT recovery slope on postoperative day 1 was associated with increases of composite complications (odds ratio 0.742; 95% confidence interval (CI) 0.584 to 0.943; P = 0.015) and hospital length of stay (regression coefficient (B) -1.276; 95% CI -2.440 to -0.112; P = 0.032). CONCLUSION: Microvascular reactivity largely recovered on postoperative day 1 in the patients without composite complications, but this restoration was attenuated in patients with composite complications. TRIAL REGISTRATION: ClinicalTrials.gov NCT01713192. Registered 22 October 2012.

Percutaneous superior vena cava drainage during minimally invasive mitral valve surgery: a randomized, crossover study.

OBJECTIVE: Minimally invasive techniques commonly are applied to mitral valve surgery; however, there has been little research investigating the optimal methods of cardiopulmonary bypass for the right minithoracotomy approach. Controversy exists as to whether a percutaneous superior vena cava drainage cannula (PSVC) is necessary during these operations. The authors, therefore, sought to determine the effect of using a percutaneous superior vena cava catheter on brain near-infrared spectroscopy, blood lactate levels, hemodynamics and surgical parameters. DESIGN: Randomized, blinded, crossover trial. SETTING: Tertiary care university hospital. PARTICIPANTS: Patients undergoing minimally invasive mitral valve surgery via a right minithoracotomy. INTERVENTIONS: Twenty minutes of either clamped or unclamped percutaneous superior vena cava neck catheter drainage, during mitral valve repair. MEASUREMENT AND MAIN RESULTS: For the primary outcome of brain near-infrared spectroscopy, there were no differences between the two groups (percutaneous superior vena cava clamped 55.0%±11.6% versus unclamped 56.1%±10.2%) (p = 0.283). For the secondary outcomes pH (clamped 7.35±0.05 versus unclamped 7.37±0.05 p = 0.015), surgical score (clamped 1.96±1.14 versus unclamped 1.22±0.51 p = 0.002) and CVP (clamped 11.6 mmHg±4.8 mmHg versus unclamped 6.1 mmHg±6.1 mmHg p<0.001) were significantly different. CONCLUSIONS: The use of a percutaneous superior vena cava drainage improved surgical visualization and lowered CVP, but had no effect on brain near infrared spectroscopy during minimally invasive mitral valve surgery. (ClinicalTrials.gov Identifier: NCT01166841).

Intraoperative Cerebral Autoregulation Assessment Using Ultrasound-Tagged Near-Infrared-Based Cerebral Blood Flow in Comparison to Transcranial Doppler Cerebral Flow Velocity: A Pilot Study.

OBJECTIVE: This was a pilot study comparing the ability of a new ultrasound-tagged near-infrared (UT-NIR) device to detect cerebral autoregulation (CA) in comparison to transcranial Doppler (TCD). DESIGN: An unblinded, prospective, clinical feasibility study. SETTING: Tertiary-care university hospital cardiac surgical operating rooms. PARTICIPANTS: Twenty adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). INTERVENTIONS: There were no clinical interventions based on study monitoring devices, but a continuous correlation analysis of digital data from transcranial Doppler (TCD) velocity was compared with a novel UT-NIR device and correlation analysis of change signals versus mean arterial pressure was performed in order to detect presence or absence of intact CA and for determination of the lower limit of cerebral autoregulation during CPB. MEASUREMENTS AND MAIN RESULTS: Similar and highly significant concordance (κ = 1.00; p<0.001) was demonstrated between the 2 methodologies for determination of CA, indicating good correlation between the 2 methodologies. Intact CA was absent in 2 patients during CPB, and both devices were able to detect this. CONCLUSIONS: To the authors' knowledge this is the first clinical report of a UT-NIR device that shows promise as a clinically useful modality for detection of CA and the lower limit of cerebral autoregulation. The utility of UT-NIR was demonstrated further during times at which extensive usage of electrocautery or functional absence of the transcranial window rendered TCD uninterpretable.

Use of near infrared spectroscopy to detect impaired tissue oxygen saturation in patients with complex regional pain syndrome type 1.

PURPOSE: Deep tissue hypoxia has been hypothesized in the pathogenesis of complex regional pain syndrome type 1 (CRPS 1) for some patients. The purpose of this study was to determine if near-infrared spectroscopy (NIRS) could detect differences in deep tissue oxygen saturation (StO2) and microcirculatory function in the hands of patients with CRPS 1. METHODS: Tissue oxygen saturation was evaluated at baseline and during an ischemia reperfusion challenge using vascular occlusion testing (VOT) in affected vs unaffected hands of patients with unilateral upper limb CRPS 1. A non-randomized experimental study design was used with baseline StO2 as the primary outcome measure. Secondary outcome measures were occlusion and reperfusion slopes from VOT. Values were compared with the unaffected, contralateral hand and with the dominant and non-dominant hands of sex and age-matched volunteers. Correlations between values derived from NIRS and measures of pain and function from the Brief Pain Inventory (BPI) and the Disability of the Arm, Shoulder and Hand (DASH) questionnaires were explored. RESULTS: Independent of handedness, the baseline StO2 of the affected hands of ten CRPS 1 patients was significantly lower than that of their unaffected hands (-5.8%; 95% confidence interval [CI] -10.6 to -1.0; P = 0.02). The baseline StO2 of affected CRPS 1 hands was also significantly lower than the non-dominant hands of ten volunteers (-7.3%; 95% CI -12.4 to -2.3; P = 0.007). Differences in VOT occlusion and reperfusion slopes did not reveal changes that could be uniquely attributed to CRPS 1. No significant correlations were detected between values derived from VOT and values for pain and function obtained from BPI and DASH questionnaires for patients with CRPS 1. CONCLUSIONS: Hands of patients affected by CRPS 1 of the upper limb showed significantly lower StO2 compared with their unaffected contralateral hand as well as the hands of control subjects. This trial was registered at: ClinicalTrials.gov: NCT01586377.

A novel assessment of peripheral tissue microcirculatory vasoreactivity using vascular occlusion testing during cardiopulmonary bypass.

OBJECTIVE: Cardiac surgery and cardiopulmonary bypass are associated with release of inflammatory mediators and microcirculatory alterations that result in organ dysfunction. Near-infrared spectroscopic measurement of tissue oxygen saturation (StO2) and the vascular occlusion test (VOT) were utilized in a study of elective cardiac surgical patients as a novel, noninvasive method of assessing microcirculatory vasoreactivity during nonpulsatile cardiopulmonary bypass (CPB). The objective of this pilot study was to determine whether differences in microcirculatory function and vasoreactivity could be measured in cardiac surgery using StO2 and VOT. DESIGN: A prospective, observational trial. SETTING: Tertiary care teaching hospital. PARTICIPANTS: Thirteen patients undergoing elective cardiac surgery using tepid, nonpulsatile cardiopulmonary bypass. INTERVENTIONS: Patients had continuous regional oxygen saturation monitoring using near-infrared spectroscopy and vascular occlusion tests performed in the perioperative period before, during, and after cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: Occlusion slope and hyperemic area did not vary significantly. Mean reperfusion slope was significantly lower during cardiopulmonary bypass (2.4%/second) compared to before and after bypass (4.1 and 3.5%/second, respectively). Reperfusion slope decreased as a function of CPB duration. CONCLUSIONS: This pilot study demonstrates a significant difference in reperfusion slopes during cardiopulmonary bypass when compared to prebypass and postbypass, suggesting impaired peripheral microvascular reactivity. Reperfusion slopes also exhibited a successive decline with duration of CPB, implying worsening microcirculatory dysfunction that returned to baseline values in all patients within 1 hour of separation from CPB. This noninvasive technique has potential to optimize circulatory parameters during cardiopulmonary bypass.

A prospective observational study of seizures after cardiac surgery using continuous EEG monitoring.

INTRODUCTION: Recently, there have been several retrospective reports suggesting an increased frequency in seizures after cardiopulmonary bypass, associated with increased patient morbidity. We sought to prospectively investigate the incidence of electrographic seizures without clear convulsive clinical correlates and subsequent neurologic injury following cardiac surgery. METHODS: This single-center, prospective, observational study used continuous subhairline electroencephalographic (cEEG) monitoring in the intensive care unit following routine cardiac surgery, ranging from coronary bypass surgery to complex aortic arch reconstruction. The primary outcome was the proportion of patients developing postoperative seizures, as confirmed on cEEG monitoring. Secondary outcomes included neurologic injury, post-operative complications, mortality, and ICU and hospital lengths of stay. RESULTS: 101 consenting patients were included and 3 patients had seizures (2 focal and convulsive, 1 generalized and electrographic). All three patients with seizures were ≥65 years old, had "open-chamber" procedures, and had cardiopulmonary bypass times >120 min. One of the 3 patients with seizures was exposed to higher doses of tranexamic acid. None of the patients with seizures had permanent neurologic sequelae and all were doing well at 1-year follow-up. There was no increased morbidity or mortality in patients with seizures. CONCLUSIONS: Electrographic seizures occur infrequently after cardiac surgery and are generally associated with a good prognosis. Prophylactic cEEG monitoring is unlikely to be cost-effective in this population. (ClinicalTrials.gov Identifier: NCT01291992).

Assessing changes in regional cerebral hemodynamics in adults with a high-density full-head coverage time-resolved near-infrared spectroscopy device.

Significance: Cerebral oximeters have the potential to detect abnormal cerebral blood oxygenation to allow for early intervention. However, current commercial systems have two major limitations: (1) spatial coverage of only the frontal region, assuming that surgery-related hemodynamic effects are global and (2) susceptibility to extracerebral signal contamination inherent to continuous-wave near-infrared spectroscopy (NIRS). Aim: This work aimed to assess the feasibility of a high-density, time-resolved (tr) NIRS device (Kernel Flow) to monitor regional oxygenation changes across the cerebral cortex during surgery. Approach: The Flow system was assessed using two protocols. First, digital carotid compression was applied to healthy volunteers to cause a rapid oxygenation decrease across the ipsilateral hemisphere without affecting the contralateral side. Next, the system was used on patients undergoing shoulder surgery to provide continuous monitoring of cerebral oxygenation. In both protocols, the improved depth sensitivity of trNIRS was investigated by applying moment analysis. A dynamic wavelet filtering approach was also developed to remove observed temperature-induced signal drifts. Results: In the first protocol (28±5 years; five females, five males), hair significantly impacted regional sensitivity; however, the enhanced depth sensitivity of trNIRS was able to separate brain and scalp responses in the frontal region. Regional sensitivity was improved in the clinical study given the age-related reduction in hair density of the patients (65±15 years; 14 females, 13 males). In five patients who received phenylephrine to treat hypotension, different scalp and brain oxygenation responses were apparent, although no regional differences were observed. Conclusions: The Kernel Flow has promise as an intraoperative neuromonitoring device. Although regional sensitivity was affected by hair color and density, enhanced depth sensitivity of trNIRS was able to resolve differences in scalp and brain oxygenation responses in both protocols.