Childhood Maltreatment and Leukocyte Telomere Length: Cardiac Vagal Activity Influences the Relation in Older Adults.

OBJECTIVE: Childhood maltreatment is associated with shorter leukocyte telomere length (LTL). However, the influence of cardiac vagal control on this relation is unknown. We examined whether cardiac vagal control at rest and in response to stress moderates or cross-sectionally mediates the relationship between childhood maltreatment and LTL. METHODS: Participants were 1179 men and women (aged 65 [7.2] years) suffering from coronary artery disease or non-cardiovascular chronic disease. They completed a childhood maltreatment questionnaire and underwent a stress protocol while electrocardiogram was monitored. High-frequency heart rate variability (HF-HRV) measures were obtained at rest, during stress, and after stress in absolute and normalized units (nu). LTL was measured using quantitative polymerase chain reaction. Mediation and moderation analyses were performed. RESULT: HF-HRV and HF-HRV in normalized units (HFnu) measures did not mediate the childhood maltreatment-LTL relation. However, baseline HFnu ( p = .027) and HFnu reactivity ( p = .051) moderated the relation. Specifically, maltreatment was associated with significantly lower LTL among those with baseline HFnu at ( b = -0.059, p = .003) or below the mean ( b = -0.103, p < .001), but not among those with higher baseline HFnu. It was also associated with significantly lower LTL among participants who showed either blunted ( b = -0.058, p = .004) or increased HFnu ( b = -0.099, p = .001) responses to stress but not in those with large decreases in HFnu. CONCLUSIONS: Childhood maltreatment was associated with lower LTL in those who showed a distinct cardiac vagal profile at baseline and in response to stress. The mechanisms and implications remain to be determined.

Electroencephalography-Guided Anesthesia and Delirium in Older Adults After Cardiac Surgery: The ENGAGES-Canada Randomized Clinical Trial.

Importance: Intraoperative electroencephalogram (EEG) waveform suppression, suggesting excessive general anesthesia, has been associated with postoperative delirium. Objective: To assess whether EEG-guided anesthesia decreases the incidence of delirium after cardiac surgery. Design, Setting, and Participants: Randomized, parallel-group clinical trial of 1140 adults 60 years or older undergoing cardiac surgery at 4 Canadian hospitals. Recruitment was from December 2016 to February 2022, with follow-up until February 2023. Interventions: Patients were randomized in a 1:1 ratio (stratified by hospital) to receive EEG-guided anesthesia (n = 567) or usual care (n = 573). Patients and those assessing outcomes were blinded to group assignment. Main Outcomes and Measures: The primary outcome was delirium during postoperative days 1 through 5. Intraoperative measures included anesthetic concentration and EEG suppression time. Secondary outcomes included intensive care and hospital length of stay. Serious adverse events included intraoperative awareness, medical complications, and 30-day mortality. Results: Of 1140 randomized patients (median [IQR] age, 70 [65-75] years; 282 [24.7%] women), 1131 (99.2%) were assessed for the primary outcome. Delirium during postoperative days 1 to 5 occurred in 102 of 562 patients (18.15%) in the EEG-guided group and 103 of 569 patients (18.10%) in the usual care group (difference, 0.05% [95% CI, -4.57% to 4.67%]). In the EEG-guided group compared with the usual care group, the median volatile anesthetic minimum alveolar concentration was 0.14 (95% CI, 0.15 to 0.13) lower (0.66 vs 0.80) and there was a 7.7-minute (95% CI, 10.6 to 4.7) decrease in the median total time spent with EEG suppression (4.0 vs 11.7 min). There were no significant differences between groups in median length of intensive care unit (difference, 0 days [95% CI, -0.31 to 0.31]) or hospital stay (difference, 0 days [95% CI, -0.94 to 0.94]). No patients reported intraoperative awareness. Medical complications occurred in 64 of 567 patients (11.3%) in the EEG-guided group and 73 of 573 (12.7%) in the usual care group. Thirty-day mortality occurred in 8 of 567 patients (1.4%) in the EEG-guided group and 13 of 573 (2.3%) in the usual care group. Conclusions and Relevance: Among older adults undergoing cardiac surgery, EEG-guided anesthetic administration to minimize EEG suppression, compared with usual care, did not decrease the incidence of postoperative delirium. This finding does not support EEG-guided anesthesia for this indication. Trial Registration: ClinicalTrials.gov Identifier: NCT02692300.

Perioperative Doppler ultrasound assessment of portal vein flow pulsatility in high-risk cardiac surgery patients: a multicentre prospective cohort study.

BACKGROUND: Portal vein Doppler ultrasound pulsatility measured by transoesophageal echocardiography is a marker of the haemodynamic impact of venous congestion in cardiac surgery. We investigated whether the presence of abnormal portal vein flow pulsatility is associated with a longer duration of invasive life support and postoperative complications in high-risk patients. METHODS: In this multicentre cohort study, pulsed-wave Doppler ultrasound assessments of portal vein flow were performed during anaesthesia before initiation of cardiopulmonary bypass (before CPB) and after separation of cardiopulmonary bypass (after CPB). Abnormal pulsatility was defined as portal pulsatility fraction (PPF) ≥50% (PPF50). The primary outcome was the cumulative time in perioperative organ dysfunction (TPOD) requiring invasive life support during 28 days. Secondary outcomes included major postoperative complications. RESULTS: 373 patients, 71 (22.0%) had PPF50 before CPB and 77 (24.9%) after CPB. PPF50 was associated with longer duration of TPOD (median [inter-quartile range]; before CPB: 27 h [11-72] vs 19 h [8.5-42], P=0.02; after CPB: 27 h [11-61] vs 20 h [8-42], P=0.006). After adjusting for confounders, PPF50 before CPB showed significant association with TPOD. PPF50 after CPB was associated with a higher rate of major postoperative complications (36.4% vs 20.3%, P=0.006). CONCLUSIONS: Abnormal portal vein flow pulsatility before cardiopulmonary bypass was associated with longer duration of life support therapy after cardiac surgery in high-risk patients. Abnormal portal vein flow pulsatility after cardiopulmonary bypass separation was associated with a higher risk of major postoperative complications although this association was not independent of other factors. CLINICAL TRIAL REGISTRATION: NCT03656263.

Early Detection and Correction of Cerebral Desaturation With Noninvasive Oxy-Hemoglobin, Deoxy-Hemoglobin, and Total Hemoglobin in Cardiac Surgery: A Case Series.

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.

Impact of Processed Electroencephalography in Cardiac Surgery: A Retrospective Analysis.

OBJECTIVE: The use of brain function monitoring with processed electroencephalography (pEEG) during cardiac surgery is gaining interest for the optimization of hypnotic agent delivery during the maintenance of anesthesia. The authors sought to determine whether the routine use of pEEG-guided anesthesia is associated with a reduction of hemodynamic instability during cardiopulmonary bypass (CPB) separation and subsequently reduces vasoactive and inotropic requirements in the intensive care unit. DESIGN: This is a retrospective cohort study based on an existing database. SETTING: A single cardiac surgical center. PARTICIPANTS: Three hundred patients undergoing cardiac surgery, under CPB, between December 2013 and March 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One hundred and fifty patients had pEEG-guided anesthesia, and 150 patients did not have a pEEG-guided anesthesia. Multiple logistic regression demonstrated that pEEG-guided anesthesia was not associated with a successful CPB separation (p = 0.12). However, the use of pEEG-guided anesthesia reduced by 57% the odds of being in a higher category for vasoactive inotropic score compared to patients without pEEG (odds ratio = 0.43; 95% confidence interval: 0.26-0.73; p = 0.002). Duration of mechanical ventilation, fluid balance, and blood losses were also reduced in the pEEG anesthesia-guided group (p < 0.003), but there were no differences in organ dysfunction duration and mortality. CONCLUSION: During cardiac surgery, pEEG-guided anesthesia allowed a reduction in the use of inotropic or vasoactive agents at arrival in the intensive care unit. However, it did not facilitate weaning from CPB compared to a group where pEEG was unavailable. A pEEG-guided anesthetic management could promote early vasopressor weaning after cardiac surgery.

Postoperative outcomes in surgical COVID-19 patients: a multicenter cohort study.

BACKGROUND: Data on postoperative outcomes of the COVID-19 patient population is limited. We described COVID-19 patients who underwent a surgery and the pandemic impact on surgical activities. METHODS: We conducted a multicenter cohort study between March 13 and June 192,020. We included all COVID-19 patients who underwent surgery in nine centres of the Province of Québec, the Canadian province most afflicted by the pandemic. We also included concomitant suspected COVID-19 (subsequently confirmed not to have COVID-19) patients and patients who had recovered from it. We collected data on baseline characteristics, postoperative complications and postoperative mortality. Our primary outcome was 30-day mortality. We also collected data on overall surgical activities during this first wave and during the same period in 2019. RESULTS: We included 44 COVID-19 patients, 18 suspected patients, and 18 patients who had recovered from COVID-19 at time of surgery. Among the 44 COVID-19 patients, 31 surgeries (71%) were urgent and 16 (36%) were major. In these patients, pulmonary complications were frequent (25%) and 30-day mortality was high (15.9%). This mortality was higher in patients with symptoms (23.1%) compared to those without symptoms (5.6%), although not statistically significant (p = 0.118). Of the total 22,616 cases performed among participating centres during the study period, only 0.19% had COVID-19 at the time of surgery. Fewer procedures were performed during the study period compared to the same period in 2019 (44,486 cases). CONCLUSION: In this Canadian cohort study, postoperative 30-day mortality in COVID-19 patients undergoing surgery was high (15.9%). Although few surgeries were performed on COVID-19 patients, the pandemic impact on surgical activity volume was important. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04458337 .

In Vivo Protamine Titration Using Activated Coagulation Time to Neutralize Heparin Anticoagulation in Cardiac Surgery: Proof of Concept.

OBJECTIVE: In vivo protamine titration (IVPT) is based on the observation of a plateau on the decay curve of the celite activated clotting times (ACTs) during protamine infusion for heparin reversal. The aim of the present study was to determine the optimal protamine/heparin ratio to reverse anticoagulation using IVPT curves. DESIGN: Prospective, randomized study. SETTING: Tertiary care university hospital. PARTICIPANTS: The study comprised 138 patients undergoing elective cardiac surgery requiring cardiopulmonary bypass. INTERVENTIONS: The control group was given a protamine infusion of 1.3 mg per 1 mg (100 U) of heparin over 21 minutes. ACT was measured every 3 minutes. In the test group, the protamine dose was prepared using the same ratio as for the control group, and ACT values were measured every 3 minutes until a plateau was reached (2 consecutive ACT values <160 s), at which time the protamine infusion was stopped. The protamine/heparin ratio, blood losses, transfusions, and heparin concentrations were recorded. RESULTS: The protamine dose was lower in the test group (456.00 ± 105.66 mg [control group] v 295.25 ± 100.60 mg [test group]; p < 0.0001). The mean protamine/heparin ratios were 1.30 ± 0.10 (control group) and 0.81 ± 0.22 (test group) (p < 0.0001). Heparin concentrations were greater in the test group 15 minutes (0.10 [0-0.2] U/mL v 0 [0-0.1] U/mL; p = < 0.0001) and 3 hours (0 [0-0.1] U/mL v 0 [0-0] U/mL; p = 0.0002) after protamine infusion. There was no difference in the blood losses and transfusion requirements. CONCLUSIONS: IVPT is safe and efficient in this low-risk population.

Parasympathetic Response Patterns are Associated with Metabolic Syndrome Among Older Women but Not Men.

BACKGROUND: Little is known about the role of physiological stress responses in metabolic syndrome (MetS). PURPOSE: To examine whether patterns of autonomic response to psychological stress are associated with MetS and whether this association is moderated by sex. METHODS: 1121 men and women (Mage = 65.3 ± 6.77 years) with and without coronary artery disease (CAD) underwent an anger recall stressor task. Heart rate and heart-rate variability (HRV; HF, LF/HF) were assessed. Clusters of participants showing similar patterns of response across baseline, stress, and recovery periods were created using ACECLUS and FASTCLUS in SAS. Logistic regressions included clusters and interaction between clusters and sex as independent variables, controlling for relevant covariates. ANCOVAs were conducted in secondary analyses utilizing a continuous composite representation of MetS. RESULTS: Men and women showing greater tonic and phasic HR elevations were more likely to meet MetS criteria (OR = 1.45, [95% CI = 1.02-2.07], p = .037). HF-HRV cluster interacted significantly with sex (p < .001) to predict MetS. In women, those with significant parasympathetic withdrawal to stress and poor recovery were more likely to have MetS than women with a more moderate response (OR = 2.56, [95% CI = 1.23-5.41], p = .013). Women who displayed stress-related parasympathetic activation were also at greater risk of MetS (OR = 2.30, [95% CI = 1.30-4.07], p = .004). Results using a continuous measure of MetS were generally consistent with these findings. CONCLUSION: Among older participants with CAD or other noncardiovascular disease, hyperreactivity to stress was associated with greater prevalence of MetS, particularly in women. Consistent with emerging literature, women who showed blunting or activation of parasympathetic responses to stress were similarly at greater risk.

Patient management algorithm combining processed electroencephalographic monitoring with cerebral and somatic near-infrared spectroscopy: a case series.

PURPOSE: Cerebral oximetry is a monitoring tool used in the perioperative care of cardiac surgery patients to ensure adequate cerebral perfusion and oxygenation. When combined with somatic oximetry, the differential diagnosis of cerebral desaturation can be better identified and managed more specifically, as somatic oximetry serves as a global or localized perfusion monitor (depending on its regional position). The use of processed electroencephalography (pEEG) in cardiac surgery could further guide the management of desaturation episodes, as reductions in pEEG activity without a change in the anesthetic agent level indicate potential cerebral ischemia. Continuous integration of multiple monitoring modalities are thus desirable to assess organ perfusion and organ function. CLINICAL FEATURES: Four clinical cases are presented in which the combination of pEEG and cerebro-somatic oximetry assisted with understanding the mechanism of cerebral desaturation encountered during cardiac surgery. CONCLUSION: Integrating combinations of different monitoring modalities such as cerebral and somatic oximetry with pEEG can help the diagnosis and treatment of organ malperfusion and related dysfunction.

RéSUMé: OBJECTIF: L'oxymétrie cérébrale est un outil de monitorage utilisé dans les soins périopératoires des patients de chirurgie cardiaque pour s'assurer que leur cerveau est adéquatement perfusé et oxygéné. Quand on la combine à l'oxymétrie somatique, le diagnostic différentiel de désaturation cérébrale peut être mieux identifié et géré de manière plus spécifique, car l'oxymétrie somatique permet un suivi de la perfusion globale ou localisée (selon l'emplacement du capteur). L'utilisation de l'électroencéphalographie traitée (pEEG) en chirurgie cardiaque pourrait entraîner une meilleure gestion des épisodes de désaturation dans la mesure ou une baisse de l'activité pEEG sans modification du niveau de l'agent anesthésique indique une ischémie cérébrale potentielle. L'intégration continue de multiples modalités de monitorage est donc souhaitable pour évaluer la perfusion et le fonctionnement des organes. CARACTéRISTIQUES CLINIQUES: Quatre cas cliniques sont présentés dans lesquels la combinaison de la pEEG et de l'oxymétrie cérébro-somatique a aidé à comprendre le mécanisme de désaturation cérébrale rencontrée au cours de la chirurgie cardiaque. CONCLUSION: Les combinaisons intégrant différentes modalités de monitorage, telles que l'oxymétrie cérébrale et somatique avec la pEEG, peuvent contribuer au diagnostic et au traitement des troubles de la perfusion des organes et des dysfonctionnements qui en découlent.

Myocardial Protection in Minimally Invasive Mitral Valve Surgery: Retrograde Cardioplegia Alone Using Endovascular Coronary Sinus Catheter Compared With Combined Antegrade and Retrograde Cardioplegia.

OBJECTIVE: To compare myocardial protection with retrograde cardioplegia alone with antegrade and retrograde cardioplegia in minimally invasive mitral valve surgery (MIMS). DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PARTICIPANTS: The authors studied 97 MIMS patients using retrograde cardioplegia alone and 118 MIMS patients using antegrade and retrograde cardioplegia. INTERVENTIONS: The data from patients admitted for MIMS using retrograde cardioplegia (MIMS retro) between 2009 to 2012 were compared with the data from patients undergoing MIMS with antegrade and retrograde cardioplegia (MIMS ante-retro) between 2006 and 2010 (control group). Cardioplegia in the MIMS retro group was delivered solely through an endovascular coronary sinus (CS) catheter positioned under echographic and fluoroscopic guidance. Antegrade and retrograde cardioplegia was used in the MIMS ante-retro group. Data regarding myocardial infarction (MI; creatine kinase Mb, troponin T, electrocardiogram), myocardial function, and hemodynamic stability were collected for comparison. MEASUREMENTS AND MAIN RESULTS: Adequate cardioplegia administration (CS pressure >30 mmHg and asystole) was attained in 74.2% of the patients with retrograde cardioplegia alone. In 23.7% of the patients, the addition of an antegrade cardioplegia was necessary. No difference was observed in the incidence of MI (0 MIMS retro v 1 for MIMS ante-retro, p = 0.3623), difficult separation from cardiopulmonary bypass, and postoperative malignant arrhythmia. No difference was found for maximal creatine kinase Mb (39.1 [28.0-49.1] v 37.9 [28.6-50.9]; p = 0.8299) and for maximal troponin T levels (0.39 [0.27-0.70] v 0.47 [0.32-0.79]; p = 0.1231) for MIMS retro and MIMS ante-retro, respectively. However, lactate levels in the MIMS retro group were significantly lower than in the MIMS ante-retro group (2.1 [1.4-3.05] v 2.4 [1.8-3.3], respectively; p = 0.0453). No difference was observed in duration of intensive care unit stay and death. MIMS retro patients had a shorter hospital stay (7.0 [6.0-8.0] v 8.0 [7.0-9.0] days; p = 0.0003). CONCLUSION: Retrograde cardioplegia administration alone provided comparable myocardial protection to antegrade and retrograde cardioplegia during MIMS, but was not sufficient to achieve asystole in one-fifth of patients.

A Practical Approach to Cerebro-Somatic Near-Infrared Spectroscopy and Whole-Body Ultrasound.

Near-infrared spectroscopy (NIRS) is an emerging noninvasive monitoring modality based on chromophore absorption of infrared light. Because NIRS provides instantaneous information on cerebral and somatic tissue oxygenation, it becomes mandatory to identify rapidly the etiology of impaired regional oxygenation and thus perfusion. To do so, the use of whole-body ultrasound (WHOBUS) represents a significant advance in the management of patients experiencing cerebral or somatic desaturation. This narrative review describes the authors' experience since 2002 in the use of combined NIRS and WHOBUS. A practical approach in the use of both modalities and their respective limitations is described.

Perioperative Right Ventricular Pressure Monitoring in Cardiac Surgery.

Right ventricular (RV) dysfunction is a cause of increased morbidity and mortality in both cardiac surgery and noncardiac surgery and in the intensive care unit. Early diagnosis of this condition still poses a challenge. The diagnosis of RV dysfunction traditionally is based on a combination of echocardiography, hemodynamic measurements, and clinical symptoms. This review describes the method of using RV pressure waveform analysis to diagnose and grade the severity of RV dysfunction. The authors describe the technique, optimal use, and pitfalls of this method, which has been used at the Montreal Heart Institute since 2002, and review the current literature on this method. The RV pressure waveform is obtained using a pulmonary artery catheter with the capability of measuring RV pressure by connecting a pressure transducer to the pacemaker port. The authors describe how RV pressure waveform analysis can facilitate the diagnosis of systolic and diastolic RV dysfunction, the evaluation of RV-arterial coupling, and help diagnose RV outflow tract obstruction. RV pressure waveform analysis also can be used to guide pharmacologic treatment and fluid resuscitation strategies for RV dysfunction.

Acute Right Ventricular Failure in Cardiac Surgery During Cardiopulmonary Bypass Separation: A Retrospective Case Series of 12 Years' Experience With Intratracheal Milrinone Administration.

OBJECTIVE: To report the authors' 12 years of experience with intratracheal milrinone administration and to assess the efficacy and limitations of intratracheal milrinone bolus administration for the treatment of unexpected acute right ventricular (RV) failure in patients undergoing cardiac surgery. DESIGN: Retrospective analysis. SETTING: Single-center university hospital. PARTICIPANTS: One hundred seventy-six patients (4.6%) undergoing on-pump cardiac surgery. INTERVENTIONS: Endotracheal tube administration of milrinone (5-mg bolus) after unexpected acute RV failure during separation from cardiopulmonary bypass (CPB) weaning. RV failure was defined as the simultaneous presence of all of the following criteria: (1) hemodynamic instability or difficult separation from CPB with associated elevated central venous pressure or abnormal RV pressure waveform, (2) >20% reduction of RV fractional area change from baseline evaluated by transesophageal echocardiography, and (3) anatomical visualization of impaired or absent RV wall motion by direct intraoperative visual inspection. MEASUREMENTS AND MAIN RESULTS: Intratracheal milrinone administration was found to improve RV failure in 109 patients (61.9%) whereas RV failure persisted in 67 patients (38.1%). Using a multiple logistic regression model, severely decreased left ventricular ejection fraction (<35% v >50%) (adjusted odds ratio [OR] 3.72; 95% confidence interval [CI] 1.2-11.3; p = 0.012), longer CPB time (adjusted OR 1.014; CI 1.01-1.02; p = 0.001) and elevated postoperative fluid balance (adjusted OR 1.39; CI 1.1-1.8; p = 0.02) were found to be significant predictors of persistent RV failure. CONCLUSION: Intratracheal instillation of milrinone was associated with clinical improvement of RV failure occurring during separation from CPB in almost two-thirds of patients. Factors limiting its therapeutic efficacy include severe left ventricular dysfunction, increased fluid balance, and long CPB time.

Risk Factors for Radial-to-Femoral Artery Pressure Gradient in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass.

OBJECTIVE: To identify risk factors associated with radial-to-femoral pressure gradient during cardiac surgery with cardiopulmonary bypass (CPB). DESIGN: This is a retrospective, observational study. SETTING: Single specialized cardiothoracic hospital in Montreal, Canada. PARTICIPANTS: Consecutive patients that underwent heart surgery with CPB between 2005 and 2015 (n = 435). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A radial-to-femoral pressure gradient occurred in 146 patients of the 435 patients (34%). Based on the 10,000 bootstrap samples, simple logistic regression models identified the 17 most commonly significant variables across the bootstrap runs. Using these variables, a backward multiple logistic model was performed on the original sample and identified the following independent variables: body surface area (m2) (odds ratio [OR] 0.08, 95% confidence interval [CI] 0.030-0.232), clamping time (minutes) (OR 1.01, 95% CI 1.007-1.018), fluid balance (for 1 liter) (OR 0.81, 95% CI 0.669-0.976), and preoperative hypertension (OR 1.801, 95% CI 1.131-2.868). CONCLUSION: A radial-to-femoral pressure gradient occurs in 34% of patients during cardiac surgery. Patients at risk seem to be of smaller stature, hypertensive, and undergo longer and more complex surgeries.

Myocardial Protection in Mitral Valve Surgery: Comparison Between Minimally Invasive Approach and Standard Sternotomy.

OBJECTIVE: To compare antegrade and retrograde cardioplegia administration in minimally invasive mitral valve surgery (MIMS) and open mitral valve surgery (OMS) for myocardial protection. DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PARTICIPANTS: The study comprised 118 patients undergoing MIMS and 118 patients undergoing OMS. INTERVENTIONS: The data of patients admitted for MIMS from 2006 to 2010 were reviewed. Patients undergoing isolated elective OMS from 2004 to 2006 were used as a control group. Cardioplegia in the MIMS group was delivered via the distal port of the endoaortic clamp and an endovascular coronary sinus catheter positioned using echographic and fluoroscopic guidance. Antegrade and retrograde cardioplegia were used in OMS. Data regarding myocardial infarction (MI) (creatine kinase [CK]-MB, troponin T, electrocardiography); myocardial function; and hemodynamic stability were collected. MEASUREMENTS AND MAIN RESULTS: There was no difference in the perioperative MI incidence between both groups (1 in each group, p = 0.96). No statistically significant difference was found for maximal CK-MB (35.9 µg/L [25.1-50.1] v 37.9 µg/L [28.6-50.9]; p = 0.31) or the number of patients with CK-MB levels >50 µg/L (29 v 33; p = 0.55) or CK-MB >100 µg/L (3 v 4; p = 0.70) between the OMS and MIMS groups. However, maximum troponin T levels in the MIMS group were significantly lower (0.47 µg/L [0.32-0.79] v 0.65 µg/L [0.45-0.94]; p = 0.0007). No difference in the incidence of difficult weaning from bypass and intra-aortic balloon pump use between the MIMS and OMS groups was found. CONCLUSIONS: Antegrade and retrograde cardioplegia administration during MIMS and OMS provided comparable myocardial protection.

Aerosolized Vasodilators for the Treatment of Pulmonary Hypertension in Cardiac Surgical Patients: A Systematic Review and Meta-analysis.

BACKGROUND: In cardiac surgery, pulmonary hypertension is an important prognostic factor for which several treatments have been suggested over time. In this systematic review and meta-analysis, we compared the efficacy of inhaled aerosolized vasodilators to intravenously administered agents and to placebo in the treatment of pulmonary hypertension during cardiac surgery. We searched MEDLINE, CENTRAL, EMBASE, Web of Science, and clinicaltrials.gov databases from inception to October 2015. The incidence of mortality was assessed as the primary outcome. Secondary outcomes included length of stay in hospital and in the intensive care unit, and evaluation of the hemodynamic profile. METHODS: Of the 2897 citations identified, 10 studies were included comprising a total of 434 patients. RESULTS: Inhaled aerosolized agents were associated with a significant decrease in pulmonary vascular resistance (-41.36 dyne·s/cm, P= .03) and a significant increase in mean arterial pressure (8.24 mm Hg, P= .02) and right ventricular ejection fraction (7.29%, P< .0001) when compared to intravenously administered agents. No significant hemodynamically meaningful differences were observed between inhaled agents and placebo; however, an increase in length of stay in the intensive care unit was shown with the use of inhaled aerosolized agents (0.66 days, P= .01). No other differences were observed for either comparison. CONCLUSIONS: The administration of inhaled aerosolized vasodilators for the treatment of pulmonary hypertension during cardiac surgery is associated with improved right ventricular performance when compared to intravenously administered agents. This review does not support any benefit compared to placebo on major outcomes. Further investigation is warranted in this area of research and should focus on clinically significant outcomes.

Low-Dose Versus High-Dose Tranexamic Acid Reduces the Risk of Nonischemic Seizures After Cardiac Surgery With Cardiopulmonary Bypass.

OBJECTIVE: The incidence of postoperative nonischemic seizures associated with the use of tranexamic acid (TXA) and the possibility of prevention with a low-dose regimen of TXA were evaluated. DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PARTICIPANTS: A total of 12,195 patients who underwent cardiac surgical procedures under cardiopulmonary bypass (CPB) were evaluated. INTERVENTIONS: The files of every clinical seizure case diagnosed in the surgical intensive care unit between April 2006 and April 2014 were reviewed. Patients who experienced a postoperative seizure underwent a cerebral computed tomography scan to exclude an ischemic lesion. Dosage and type of antifibrinolytic used and surgery characteristics were retrieved from perfusion files. Low-dose TXA was defined as 1,000-mg bolus, 400-mg/h infusion, and 500 mg in CPB priming. High-dose TXA was defined as 30-mg/kg bolus, 15 mg/kg/h, and 2 mg/kg in CPB priming. RESULTS: No seizure was observed in the 886 patients who did not receive antifibrinolytics. A total of 98 clinical seizures (0.8%) were recorded in the intensive care unit, and ischemic cause was excluded in the majority of them after computed tomography scan results were reviewed (91 patients [93%]). Low-dose TXA was associated with fewer seizures than was high-dose TXA (46 of 7,452 cases [0.70%] v 34 of 2,190 cases [1.55%], respectively; p < 0.0001). Open-chamber cardiac surgery also was linked to a higher incidence of seizures compared with revascularization (80 of 6,662 [1.20%] and 11 of 5,533 [0.20%], respectively; p < 0.0001). CONCLUSIONS: Lower doses of TXA were associated with a lower incidence of nonischemic seizures compared with higher doses of the drug.

Cerebral Oximetry Monitoring to Maintain Normal Cerebral Oxygen Saturation during High-risk Cardiac Surgery: A Randomized Controlled Feasibility Trial.

BACKGROUND: Cerebral oxygen desaturation during cardiac surgery has been associated with adverse perioperative outcomes. Before a large multicenter randomized controlled trial (RCT) on the impact of preventing desaturations on perioperative outcomes, the authors undertook a randomized prospective, parallel-arm, multicenter feasibility RCT to determine whether an intervention algorithm could prevent desaturations. METHODS: Eight Canadian sites randomized 201 patients between April 2012 and October 2013. The primary outcome was the success rate of reversing cerebral desaturations below 10% relative to baseline in the intervention group. Anesthesiologists were blinded to the cerebral saturation values in the control group. Intensive care unit personnel were blinded to cerebral saturation values for both groups. Secondary outcomes included the area under the curve of cerebral desaturation load, enrolment rates, and a 30-day follow-up for adverse events. RESULTS: Cerebral desaturations occurred in 71 (70%) of the 102 intervention group patients and 56 (57%) of the 99 control group patients (P = 0.04). Reversal was successful in 69 (97%) of the intervention group patients. The mean cerebral desaturation load (SD) in the operating room was smaller for intervention group patients compared with control group patients (104 [217] %.min vs. 398 [869] %.min, mean difference, -294; 95% CI, -562 to -26; P = 0.03). This was also true in the intensive care unit (P = 0.02). There were no differences in adverse events between the groups. CONCLUSIONS: Study sites were successful in reversal of desaturation, patient recruitment, randomization, and follow-up in cardiac surgery, supporting the feasibility of conducting a large multicenter RCT.

Risk Factors Involved in Central-to-Radial Arterial Pressure Gradient During Cardiac Surgery.

BACKGROUND: A central-to-radial arterial pressure gradient may occur after cardiopulmonary bypass (CPB), which, in some patients, may last for a prolonged time after CPB. Whenever there is a pressure gradient, the radial artery pressure measure may underestimate a more centrally measured systemic pressure, which may result in a misguided therapeutic strategy. It is clinically important to identify the risk factors that may predict the appearance of a central-to-radial pressure gradient, because more central sites of measurements might then be considered to monitor systemic arterial pressure in high-risk patients. The objective of this study was to assess preoperative and intraoperative risk factors for central-to-radial pressure gradient. METHODS: Seventy-three patients undergoing cardiac surgery using CPB were included in this prospective observational study. A significant central-to-radial arterial pressure gradient was defined as a difference of 25 mm Hg in systolic pressure or 10 mm Hg in mean arterial pressure for a minimum of 5 minutes. Preoperative data included demographics, presence of comorbidities, and medications. Intraoperative data included type of surgery, CPB and aortic clamping time, use of inotropic drugs, and vasodilators or vasopressors agents. The diameter of the radial and femoral artery was measured before the induction of anesthesia using B-mode ultrasonography. RESULTS: Thirty-three patients developed a central-to-radial arterial pressure gradient (45%). Patients with a significant pressure gradient had a smaller weight (71.0 ± 16.9 vs 79.3 ± 17.3 kg, P = 0.041), a smaller height (162.0 ± 9.6 vs 166.3 ± 8.6 cm, P = 0.047), a smaller radial artery diameter (0.24 ± 0.03 vs 0.29 ± 0.05 cm, P < 0.001), and were at a higher risk as determined by the Parsonnet score (30.3 ± 24.9 vs 17.0 ± 10.9, P = 0.007). In addition, a longer aortic clamping time (85.8 ± 51.0 vs 64.2 ± 29.3 minutes, P = 0.036), mitral and complex surgery (P = 0.007 and P = 0.017, respectively), and administration of vasopressin (P = 0.039) were identified as potential independent predictors of a central-to-radial pressure gradient. By using multivariate logistic regression analysis, the following independent risk factors were identified: Parsonnet score (odds ratio [OR], 1.076; 95% confidence interval [CI], 1.027-1.127, P = 0.002), aortic clamping time >90 minutes (OR, 8.521; 95% CI, 1.917-37.870, P = 0.005), and patient height (OR, 0.933, 95% CI, 0.876-0.993, P = 0.029). The relative risk (RR) estimates remained statistically significant for the Parsonnet score and the aortic clamping time ≥90 minutes (RR, 1.010; 95% CI, 1.003-1.018, P = 0.009 and RR, 2.253; 95% CI, 1.475-3.443, P < 0.001 respectively) while showing a trend for patient height (RR, 0.974; 95% CI, 0.948-1.001, P = 0.058). CONCLUSIONS: Central-to-radial gradients are common in cardiac surgery. The threshold for using a central site for blood pressure monitoring should be low in small, high-risk patients undergoing longer surgical interventions to avoid inappropriate administration of vasopressors and/or inotropic agents.

Assessment of fluid responsiveness with end-tidal carbon dioxide using a simplified passive leg raising maneuver: a prospective observational study.

BACKGROUND: Assessing fluid responsiveness is important in the management of patients with hemodynamic instability. Passive leg raising (PLR) is a validated dynamic method to induce a transient increase in cardiac preload and predict fluid responsiveness. Variations in end-tidal carbon dioxide (ETCO2) obtained by capnography correlate closely with variations in cardiac output when alveolar ventilation and carbon dioxide production are kept constant. In this prospective observational study, we tested the hypothesis that variations in ETCO2 induced by a simplified PLR maneuver can track changes in the cardiac index (CI) and thus predict fluid responsiveness. METHOD: A five-minute standardized PLR maneuver was performed in 90 paralyzed hemodynamically stable cardiac surgical patients receiving mechanical ventilation. Cardiac index was measured by thermodilution before and one minute after PLR. End-tidal CO2 measurements using capnography were obtained during the entire PLR maneuver. Fluid responsiveness was defined as a 15% increase in the CI. The Chi square test and Student's t test were used to compare responders and non-responders. Logistic regression analyses were then performed to determine factors of responsiveness. RESULTS: There were no differences between responders and non-responders in demographic and baseline hemodynamic variables. Fluid responsiveness was associated with an ETCO2 variation (ΔETCO2) of ≥ 2 mmHg during PLR [odds ratio (OR), 7.3; 95% confidence interval (CI), 2.7 to 20.2; P < 0.01; sensitivity 75%]. A low positive predictive value (54%) and a high negative predictive value (NPV) (86%) were observed. No other clinical or hemodynamic predictors were associated with fluid responsiveness. A logistic regression model established that a combination of ΔETCO2 ≥ 2 mmHg and a change in systolic blood pressure ≥ 10 mmHg induced by passive leg raising was predictive of fluid responsiveness (OR, 8.9; 95% CI, 2.5 to 32.2; P = 0.005). CONCLUSION: Use of a passive leg raising maneuver to induce variation in ETCO2 is a noninvasive and useful method to assess fluid responsiveness in paralyzed cardiac surgery patients receiving mechanical ventilation. Given its high NPV, fluid responsiveness is unlikely if a passive leg raising maneuver induces ΔETCO2 of < 2 mmHg.