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Objective Optimal oxygen management during cardiac surgery has not been established, and studies on the effects of perioperative hyperoxia on postoperative acute kidney injury (AKI) are scarce. The association between intraoperative hyperoxia and AKI after cardiac surgery involving cardiopulmonary bypass was evaluated for the present study. Design Retrospective observational study. Setting A tertiary teaching hospital. Participants Adult patients who underwent cardiac surgery with cardiopulmonary bypass from November 2006–December 2018. Interventions None. Measurements and Main Results The area above arterial oxygen partial pressure (PaO2) threshold of 300 mmHg (AOT300, mmHg × h) was used as a metric of intraoperative hyperoxia and was associated with postoperative AKI, using the logistic regression analysis. Data also were fitted using the restricted cubic spline model. Sensitivity analyses were conducted using different PaO2 thresholds (150, 200, 250, and 350 mmHg). A total of 2,926 patients were analyzed. Intraoperative AOT300 independently was associated with the risk of AKI (odds ratio 1.0009; 95% confidence interval 1.0002-1.0015). A PaO2 increment of 100 mmHg above PaO2 300 mmHg for an hour was associated with an increased risk of AKI by 9.4% (1.0009100 ≈ 1.094). In the spline model, the log-odds of AKI increased as AOT300 increased. In the sensitivity analyses, AOT250 and AOT350 also significantly were associated with the risk of AKI, whereas AOT150 and AOT200 were not. As the PaO2 threshold increased from 150 to 350 mmHg, the odds ratio gradually increased. Conclusions Intraoperative hyperoxia significantly was associated with the risk of AKI after cardiac surgery involving cardiopulmonary bypass.

Objectives Although postoperative subglottic secretion drainage prevents ventilator-associated pneumonia (VAP) after cardiac surgery, its role during the perioperative period is unclear. For the present study, the effect of subglottic secretion drainage during and after cardiac surgery on postoperative VAP was investigated. Design Retrospective, single-center, before-and-after study. Setting Perioperative care of cardiac surgical patients in a tertiary university hospital. Participants Adult patients who underwent cardiac surgery from January 2013–December 2018. Interventions Conventional and subglottic suctioning endotracheal tubes were used in the control and intervention groups before and after a change in institutional policy, respectively. In the intervention group, subglottic secretion drainage was performed continuously during surgery and intermittently after surgery. Measurements and Main Results The risk of postoperative VAP, identified by the National Healthcare Safety Network surveillance definition algorithm, was compared by weighted logistic regression. Logistic regression analyses, with propensity score matching and inverse probability weighting, also were performed. A total of 2,576 patients were analyzed (control [n = 2108]; intervention [n = 468]). Postoperative VAP occurred less frequently in the intervention group (1/468 [0.2%]) compared with the control group (30/2,108 [1.4%]). In the multivariate weighted logistic regression analysis, the risk of VAP after cardiac surgery was significantly lower in the intervention group than in the control group (odds ratio 0.29; 95% confidence interval 0.14-0.58). Similar results were obtained in multivariate analyses after propensity score matching (odds ratio 0.04; 95% confidence interval 0.01-0.14) and inverse probability weighting (odds ratio 0.16; 95% confidence interval 0.05-0.42). Conclusions Routine perioperative subglottic secretion drainage using subglottic suctioning endotracheal tubes in patients undergoing cardiac surgery was associated with a reduction in the risk of VAP after surgery.

Introduction Remote ischaemic conditioning (RIC) has been shown to prevent platelet activation during ablation for atrial fibrillation. In the recent Remote Ischaemic Preconditioning with Postconditioning Outcome trial, RIC was associated with more postoperative transfusion in the off-pump coronary artery bypass graft surgery (OPCAB) subgroup. Transient tourniquet application on the limb affects the coagulation system; however, it remains unknown whether RIC affects the coagulation system during OPCAB. Methods A total of 58 patients undergoing OPCAB were randomised to the RIC or control group. In the RIC group, four cycles of 5 min of ischaemia and 5 min of reperfusion were applied twice to the upper arm after the induction of anaesthesia (preconditioning), and after the completion of coronary anastomoses (postconditioning). Whole blood impedance aggregometry (Multiplate®) and rotational thromboelastometry (ROTEM®) were performed before the induction of anaesthesia, at the end of surgery, and at postoperative day 1. Results The decrease in whole-blood aggregation by adenosine diphosphate at the end of surgery was greater in the RIC group than in the control group, but this effect was not statistically significant (46.7 [21.4] vs. 45.8 [22.6] U, P=0.880). In ROTEM® analysis, the EXTEM area under the velocity curve was lower in the RIC group than in the control group at the end of surgery (3,567 [1,399–5,794] vs. 5,693 [4,718–6,179] mm*100, respectively; P=0.03). However, there was no difference in other Multiplate® or ROTEM® parameters. An increased tendency of perioperative bleeding was identified in the RIC group. Discussion Although some parameters indicated a tendency for hypocoagulation in the RIC group at the end of surgery, most effects were not statistically significant. RIC does not significantly affect perioperative platelet aggregability and coagulation in patients undergoing OPCAB.

Introduction Cerebral oximetry has been widely used to measure regional oxygen saturation in brain tissue, especially during cardiac surgery. Despite its popularity, there have been inconsistent results on the use of cerebral oximetry during cardiac surgery, and few studies have evaluated cerebral oximetry during off pump coronary artery bypass graft surgery (OPCAB). Methods To evaluate the relationship between intraoperative cerebral oximetry and postoperative delirium in patients who underwent OPCAB, we included 1,439 patients who underwent OPCAB between October 2004 and December 2016 and among them, 815 patients with sufficient data on regional cerebral oxygen saturation (rSO2) were enrolled in this study. We retrospectively analysed perioperative variables and the reduction in rSO2 below cut-off values of 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, and 35%. Furthermore, we evaluated the relationship between the reduction in rSO2 and postoperative delirium. Results Delirium occurred in 105 of 815 patients. In both univariable and multivariable analyses, the duration of rSO2 reduction was significantly longer in patients with delirium at cut-offs of Discussion In patients undergoing OPCAB, intraoperative rSO2 was associated with postoperative delirium. The cut-off values for intraoperative rSO2 were 50% for the total patient population and 55% for patients younger than 68 years.

Introduction Remote ischemic conditioning (RIC) has been proven to have organ-protective effects but clinical results for RIC have been inconsistent among cardiac surgery patients. Although there has been several hypothesis for these inconsistent result in cardiac surgery patient, it has not been proven, yet. Tissue oxygen saturation (StO2) and heart rate variability (HRV) reflect peripheral micro-circulation and autonomic nervous system activity, respectively. However, changes in these metrics have not been well-documented during RIC. We hypothesized that RIC effect may be attenuated in the patients undergoing cardiac surgery and that may be reflected on StO2 changes and HRV. We measured and analyzed the changes in StO2 and HRV during RIC in cardiac surgery patients and healthy volunteers. Methods Ten patients undergoing cardiac surgery and ten healthy male volunteers were included in this pilot study. Exclusion criteria were as follows: systolic or diastolic blood pressure >150 or >100 mmHg, body mass index 30 kg/m2, uncontrolled hypertension or diabetes mellitus, use of beta-blockers, any anomaly in the upper extremities, peripheral vascular disease or coagulopathy, and refusal to participate. Subjects received RIC treatment, consisting of four cycles of 5-min ischemia with cuff inflation to 200 mmHg followed by 5-min reperfusion by deflation of the cuff (which was applied to the upper arm). Changes in StO2, measured at the thenar eminence, and HRV, according to R-R intervals of the electrocardiogram, were recorded during RIC. Results During RIC, there was no difference between the two groups in baseline StO2, occlusion or recovery slope. The lowest StO2 during the ischemic period of RIC decreased in cardiac surgery patients (adjusted p = 0.042) but increased in healthy volunteers (adjusted p = 0.006). The mean difference between the groups in the percentage change of the lowest StO2 value was 20% (95% CI, 9–32%, p = 0.002). Among HRV parameters, the low-frequency domain, which corresponds to sympathetic system activity, increased after RIC in healthy volunteers, but not in the patient group (p = 0.028 and p = 0.169, respectively). Discussion Our results suggest that tissue oxygen content is depleted during RIC in cardiac surgery patients, but preserved in healthy volunteers. Sympathetic system activity seems to increase during RIC in healthy volunteers, while not being affected in cardiac surgery patients. These results show that RIC mechanisms may be attenuated in cardiac surgery patients.

The aim of this study was to evaluate the ability of pulse-pressure variation to predict fluid responsiveness during heart displacement for off-pump coronary artery bypass surgery using receiver operating characteristic analysis.A prospective study.A clinical study in a single cardiac anesthesia institution.Thirty-five patients undergoing elective off-pump coronary artery bypass surgery.Central venous pressure, pulmonary arterial occlusion pressure, pulse-pressure variation, and cardiac index were measured 5 minutes after revascularization of the left anterior descending coronary artery and before heart displacement. Immediately after heart displacement for revascularization of the left circumflex artery, and 10 minutes after fluid loading with hydroxyethyl starch 6% (10 mL/kg) during heart displacement, the measurements were repeated. Patients whose cardiac indices increased by ≥15% from fluid loading were defined as responders. After heart displacement, only pulse-pressure variation showed significant difference between the responders and nonresponders (13.48 ± 6.42 v 7.33 ± 3.81, respectively; p0.01). Moreover, receiver operating characteristic analysis showed that pulse-pressure variation successfully predicted fluid responsiveness (area under the curve = 0.839, p = 0.0001). Pulse-pressure variation7.69% identified the responders, with a sensitivity of 86% and a specificity of 83%.Pulse-pressure variation successfully predicted fluid responsiveness and would be useful in guiding fluid management during heart displacement for off-pump coronary artery bypass surgery.

e C AINTAINING CARDIOVASCULAR STABILITY is one of the major goals of anesthetic management of ff-pump coronary artery bypass graft (OPCAB) surgery. This equires accurate diagnosis and management of the causes of ardiovascular instability. Gas embolism is a very rare cause of hypotension during PCAB, but there have been several reports of gas emboism during endoscopic saphenectomy for coronary artery ypass grafting.1-3 In this case report, the authors describe a O2 embolism caused by a CO2 blower while repairing an njury to a coronary vein during OPCAB. A CO2 blower was sed to enhance visualization by deflecting blood away from he anastomotic site on the beating heart.4,5 This is the first ase of gas embolism caused by this technique reported in he literature.