The effect of intra-operative hypotension on acute kidney injury, postoperative mortality and length of stay following emergency hip fracture surgery.

The association between intra-operative hypotension and postoperative acute kidney injury, mortality and length of stay has not been comprehensively evaluated in a large single-centre hip fracture population. We analysed electronic anaesthesia records of 1063 patients undergoing unilateral hip fracture surgery, collected from 2015 to 2018. Acute kidney injury, 3-, 30- and 365-day mortality and length of stay were evaluated to assess the relationship between intra-operative hypotension absolute values (≤ 55, 60, 65, 70 and 75 mmHg) and duration of hypotension. The rate of acute kidney injury was 23.7%, mortality at 3-, 30- and 365 days was 3.7%, 8.0% and 25.3%, respectively, and median (IQR [range]) length of stay 8 (6-12 [0-99]) days. Median (IQR [range]) time ≤ MAP 55, 60, 65, 70 and 75 mmHg was 0 (0-0.5[0-72.1]); 0 (0-4.4 [0-104.9]); 2.2 (0-8.7 [0-144.2]); 6.6 (2.2-19.7 [0-198.8]); 17.5 (6.6-37.1 [0-216.3]) minutes, and percentage of surgery time below these thresholds was 1%, 2.5%, 7.9%, 12% and 21% respectively. There were some univariate associations between hypotension and mortality; however, these were no longer evident in multivariable analysis. Multivariable analysis found no association between hypotension and acute kidney injury. Acute kidney injury was associated with male sex, antihypertensive medications and cardiac/renal comorbidities. Three-day mortality was associated with delay to surgery ? 48 hours, whilst 30-day and 365-day mortality was associated with delay to surgery ≥ 48 hours, impaired cognition and cardiac/renal comorbidities. While the rate of acute kidney injury was similar to other studies, use of vasopressors and fluids to reduce the time spent at hypotensive levels failed to reduce this complication. Intra-operative hypotension at the levels observed in this cohort may not be an important determinant of acute kidney injury, postoperative mortality and length of stay.

Deep learning models for the prediction of intraoperative hypotension.

BACKGROUND: Intraoperative hypotension is associated with a risk of postoperative organ dysfunction. In this study, we aimed to present deep learning algorithms for real-time predictions 5, 10, and 15 min before a hypotensive event. METHODS: In this retrospective observational study, deep learning algorithms were developed and validated using biosignal waveforms acquired from patient monitoring of noncardiac surgery. The classification model was a binary classifier of a hypotensive event (MAP <65 mm Hg) or a non-hypotensive event by analysing biosignal waveforms. The regression model was developed to directly estimate the MAP. The primary outcome was area under the receiver operating characteristic (AUROC) curve and the mean absolute error (MAE). RESULTS: In total, 3301 patients were included. For invasive models, the multichannel model with an arterial pressure waveform, electrocardiography, photoplethysmography, and capnography showed greater AUROC than the arterial-pressure-only models (AUROC15-min, 0.897 [95% confidence interval {CI}: 0.894-0.900] vs 0.891 [95% CI: 0.888-0.894]) and lesser MAE (MAE15-min, 7.76 mm Hg [95% CI: 7.64-7.87 mm Hg] vs 8.12 mm Hg [95% CI: 8.02-8.21 mm Hg]). For the noninvasive models, the multichannel model showed greater AUROCs than that of the photoplethysmography-only models (AUROC15-min, 0.762 [95% CI: 0.756-0.767] vs 0.694 [95% CI: 0.686-0.702]) and lesser MAEs (MAE15-min, 11.68 mm Hg [95% CI: 11.57-11.80 mm Hg] vs 12.67 [95% CI: 12.56-12.79 mm Hg]). CONCLUSIONS: Deep learning models can predict hypotensive events based on biosignals acquired using invasive and noninvasive patient monitoring. In addition, the model shows better performance when using combined rather than single signals.

Effect of fluid strategy on stroke volume, cardiac output, and fluid responsiveness in adult patients undergoing major abdominal surgery: a sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial.

BACKGROUND: We designed a prospective sub-study of the larger Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial to measure differences in stroke volume and other haemodynamic parameters at the end of the intraoperative fluid protocols. The haemodynamic effects of the two fluid regimens may increase our understanding of the observed perioperative outcomes. METHODS: Stroke volume and cardiac output were measured with both an oesophageal Doppler ultrasound monitor and arterial pressure waveform analysis. Stroke volume variation, pulse pressure variation, and plethysmographic variability index were also obtained. A passive leg raise manoeuvre was performed to identify fluid responsiveness. RESULTS: Analysis of 105 patients showed that the primary outcome, Doppler monitor-derived stroke volume index, was higher in the liberal group: restrictive 38.5 (28.6-48.8) vs liberal 44.0 (34.9-61.9) ml m-2; P=0.043. Similarly, there was a higher cardiac index in the liberal group: 2.96 (2.32-4.05) vs 2.42 (1.94-3.26) L min-1 m-2; P=0.015. Arterial-pressure-based stroke volume and cardiac index did not differ, nor was there a significant difference in stroke volume variation, pulse pressure variation, or plethysmographic variability index. The passive leg raise manoeuvre showed fluid responsiveness in 40% of restrictive and 30% of liberal protocol patients (not significant). CONCLUSIONS: The liberal fluid group from the RELIEF trial had significantly higher Doppler ultrasound monitor-derived stroke volume and cardiac output compared with the restrictive fluid group at the end of the intraoperative period. Measures of fluid responsiveness did not differ significantly between groups. CLINICAL TRIAL REGISTRATION: ACTRN12615000125527.

The cumulative duration of bispectral index less than 40 concurrent with hypotension is associated with 90-day postoperative mortality: a retrospective study.

BACKGROUND: The relationship between intraoperative low bispectral index (BIS) values and poor clinical outcomes has been controversial. Intraoperative hypotension is associated with postoperative complication. The purpose of this study was to investigate the influence of intraoperative low BIS values and hypotension on postoperative mortality in patients undergoing major abdominal surgery. METHODS: This retrospective study analyzed 1862 cases of general anesthesia. We collected the cumulative time of BIS values below 20 and 40 as well as electroencephalographic suppression and documented the incidences in which these states were maintained for at least 5 min. Durations of intraoperative mean arterial pressures (MAP) less than 50 mmHg were also recorded. Multivariable logistic regression was used to evaluate the association between suspected risk factors and postoperative mortality. RESULTS: Ninety-day mortality and 180-day mortality were 1.5 and 3.2% respectively. The cumulative time in minutes for BIS values falling below 40 coupled with MAP falling below 50 mmHg was associated with 90-day mortality (odds ratio, 1.26; 95% confidence interval, 1.04-1.53; P = .019). We found no association between BIS related values and 180-day mortality. CONCLUSIONS: The cumulative duration of BIS values less than 40 concurrent with MAP less than 50 mmHg was associated with 90-day postoperative mortality, not 180-day postoperative mortality.

Anesthetic Management Using Multiple Closed-loop Systems and Delayed Neurocognitive Recovery: A Randomized Controlled Trial.

BACKGROUND: Cognitive changes after anesthesia and surgery represent a significant public health concern. We tested the hypothesis that, in patients 60 yr or older scheduled for noncardiac surgery, automated management of anesthetic depth, cardiac blood flow, and protective lung ventilation using three independent controllers would outperform manual control of these variables. Additionally, as a result of the improved management, patients in the automated group would experience less postoperative neurocognitive impairment compared to patients having standard, manually adjusted anesthesia. METHODS: In this single-center, patient-and-evaluator-blinded, two-arm, parallel, randomized controlled, superiority study, 90 patients having noncardiac surgery under general anesthesia were randomly assigned to one of two groups. In the control group, anesthesia management was performed manually while in the closed-loop group, the titration of anesthesia, analgesia, fluids, and ventilation was performed by three independent controllers. The primary outcome was a change in a cognition score (the 30-item Montreal Cognitive Assessment) from preoperative values to those measures 1 week postsurgery. Secondary outcomes included a battery of neurocognitive tests completed at both 1 week and 3 months postsurgery as well as 30-day postsurgical outcomes. RESULTS: Forty-three controls and 44 closed-loop patients were assessed for the primary outcome. There was a difference in the cognition score compared to baseline in the control group versus the closed-loop group 1 week postsurgery (-1 [-2 to 0] vs. 0 [-1 to 1]; difference 1 [95% CI, 0 to 3], P = 0.033). Patients in the closed-loop group spent less time during surgery with a Bispectral Index less than 40, had less end-tidal hypocapnia, and had a lower fluid balance compared to the control group. CONCLUSIONS: Automated anesthetic management using the combination of three controllers outperforms manual control and may have an impact on delayed neurocognitive recovery. However, given the study design, it is not possible to determine the relative contribution of each controller on the cognition score.

Perioperative goal-directed therapy - What is the evidence?

Perioperative goal-directed therapy aims at optimizing global hemodynamics during the perioperative period by titrating fluids, vasopressors, and/or inotropes to predefined hemodynamic goals. There is evidence on the benefit of perioperative goal-directed therapy, but its adoption into clinical practice is slow and incomprehensive. Current evidence indicates that treating patients according to perioperative goal-directed therapy protocols reduces morbidity and mortality, particularly in patients having high-risk surgery. Perioperative goal-directed therapy protocols need to be started early, should include vasoactive agents in addition to fluids, and should target blood flow related variables. Future promising developments in the field of perioperative goal-directed therapy include personalized hemodynamic management and closed-loop system management.

Predictors of Atherosclerotic Change in Unruptured Intracranial Aneurysms and Parent Arteries During Clipping.

OBJECTIVES: To identify predictors of atherosclerotic change in aneurysms and parent arteries, and to retrospectively analyze outcomes from clipped aneurysms that showed atherosclerotic changes. METHODS: Between May 2017 and April 2018, we collected a total of 151 clipping cases and reviewed records of operation videos to classify atherosclerosis by location (dome, neck of aneurysm, or parent artery). To identify predictors of atherosclerotic change in aneurysms, we analyzed baseline demographic characteristics, preoperative images, and Framingham Risk Scores (FRS). We also analyzed incomplete clipping cases according to atherosclerosis presence and location. RESULT: This study cohort included 110 women (mean age, 59.3 ± 7.1 years) and 41 men (mean age, 55.9 ± 9.6 years). Atherosclerotic change was seen in 77 cases. FRS, diabetes mellitus, and aneurysm size were identified as independent risk factors for atherosclerotic change in multivariate logistic regression analysis. There were 11 incomplete clipping cases (7.2%). Among the 30 cases with atherosclerotic change in the neck were 10 cases of incomplete clipping (P < 0.001). CONCLUSIONS: FRS, diabetes mellitus, and aneurysm size as predictors of atherosclerosis in patients undergoing aneurysm surgery can help guide surgical decisions and performance.

Maternal anaesthesia in open and fetoscopic surgery of foetal open spinal neural tube defects: A retrospective cohort study.

BACKGROUND: Prenatal myelomeningocele repair by open surgery can improve the neurological prognosis of children with this condition. A shift towards a fetoscopic approach seems to reduce maternal risks and improve obstetric outcomes. OBJECTIVE: The aim of this study was to report on the anaesthetic management of women undergoing prenatal open or fetoscopic surgery for neural tube defects. DESIGN: A retrospective cohort study. SETTING: Prenatal myelomeningocele repair research group, Vall d'Hebron University Hospital, Spain. INTERVENTION: Intra-uterine foetal repairs of spina bifida between 2011 and 2016 were reviewed. Anaesthetic and vasoconstrictor drugs, fluid therapy, maternal haemodynamic changes during surgery, blood gas changes during CO2 insufflation for fetoscopic surgery, and maternal and foetal complications were noted. RESULTS: Twenty-nine foetuses with a neural tube defect underwent surgery, seven (24.1%) with open and 22 (75.9%) with fetoscopic surgery. There were no significant differences in maternal doses of opioids or neuromuscular blocking agents. Open surgery was associated with higher dose of halogenated anaesthetic agents [maximum medium alveolar concentration (MAC) sevoflurane 1.90 vs. 1.50%, P = 0.01], higher need for intra-operative tocolytic drugs [five of seven (71.4%) and two of 22 (9.1%) required nitroglycerine, P = 0.001], higher volume of colloids (500 vs. 300 ml, P = 0.036) and more postoperative tocolytic drugs (three drugs in all seven cases (100%) of open and in one of 21 (4.76%) of fetoscopic surgery, P < 0.001). Median mean arterial pressure was lower in open than in fetoscopic surgery. SBP, DBP and mean blood pressure decreased during uterine exposure, and this descent was more acute in open surgery. Use of vasoconstrictor drugs was related to the time of uterine exposure, but not to surgical technique. Blood gas analysis was not affected by CO2 insufflation during fetoscopic surgery. CONCLUSION: Open surgery was associated with more maternal haemodynamic changes and higher doses of halogenated anaesthetic and tocolytics agents than fetoscopic surgery.

Myasthenia Gravis and Thymoma Surgery: A Clinical Update for the Cardiothoracic Anesthesiologist.

Myasthenia gravis (MG) is a rare neuromuscular disorder characterized by skeletal muscle weakness. Patients with MG who have thymoma and thymic hyperplasia have indications for thymectomy. The perioperative care of patients with MG scheduled for thymus resection should be focused on optimizing their neuromuscular function, identifying factors related to postoperative mechanical ventilation, and avoiding of triggers associated with myasthenic or cholinergic crisis. Minimally invasive surgical techniques, use of regional analgesia, and avoidance or judicious administration of neuromuscular blocking drugs (NMBs) is recommended during the perioperative period. If NMBs are used, sugammadex appears to be the drug of choice to restore adequately the neuromuscular transmission. In patients with postoperative myasthenic crisis, plasma exchange or intravenous immune globulin and mechanical support is recommended.

Intraoperative assessment of left-ventricular diastolic function by two-dimensional speckle tracking echocardiography: relationship between pulmonary capillary wedge pressure and peak longitudinal strain rate during isovolumetric relaxation in patients undergoing coronary artery bypass graft surgery.

OBJECTIVES: Two-dimensional speckle tracking echocardiography has advantages over tissue Doppler imaging during isovolumetric relaxation for predicting left-ventricular end-diastolic pressure in non-surgical patients. Considering the direct and indirect effects of general anesthesia on hemodynamics, we examined correlations between strain-based indices during isovolumetric relaxation and pulmonary capillary wedge pressure in anesthetized patients. Moreover, we determined applicable cut-off values for strain-based indices to predict pulmonary capillary wedge pressure ≥15 mmHg intraoperatively. DESIGN: Retrospective clinical study. SETTING: Single university hospital. PARTICIPANTS: Thirty adult patients with preserved ejection fraction undergoing coronary artery bypass grafting. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two-dimensional speckle tracking echocardiography was used to measure strain rate during isovolumetric relaxation (SRIVR) and to calculate the mitral early diastolic inflow (E) to SRIVR ratio (E/SRIVR). Tissue Doppler imaging was used to calculate the E to early diastolic velocity at the lateral mitral annulus ratio (lateral E/e'). SRIVR and E/SRIVR showed strong correlations with pulmonary capillary wedge pressure (r = 0.80 and 0.73, respectively; p < 0.001 and p < 0.001). Lateral E/e' correlated with pulmonary capillary wedge pressure (r = 0.42; p < 0.05). SRIVR predicted high pulmonary capillary wedge pressure better than lateral E/e' did (areas under the receiver operating characteristic curves, 0.94-vs. 0.47, respectively). SRIVR <0.2 s-1 had a sensitivity of 100% and a specificity of 81% for predicting pulmonary capillary wedge pressure ≥15 mmHg. CONCLUSIONS: SRIVR is superior to tissue Doppler indices for predicting pulmonary capillary wedge pressure intraoperatively in patients with coronary artery disease and preserved ejection fraction.

The Effects of Secondhand Smoke Exposure on Postoperative Pain and Ventilation Values During One-Lung Ventilation: A Prospective Clinical Trial.

OBJECTIVES: To investigate the relationships between secondhand smoke (SHS) exposure and oxygenation during one-lung ventilation (OLV) in lobectomy surgery and between SHS exposure and postoperative analgesic consumption. DESIGN: Prospective study. SETTING: University, Faculty of Medicine, operating room. PARTICIPANTS: Sixty adult patients with American Society of Anesthesiologists score II to III, aged 18 to 65 years, with a body mass index (BMI) <35 kg/m2 scheduled for lobectomy surgery by open thoracotomy. INTERVENTIONS: Patients were divided into 2 groups: the SHS group (n = 30) (urine cotinine level ≥6.0 ng/mL) and the NS (nonsmoker) group (n = 30) (urine cotinine level <6.0 ng/mL and no smoking history). SHS exposure was defined according to a previously published algorithm. MEASUREMENTS AND MAIN RESULTS: Noninvasive blood pressure, electrocardiography, capnography, and peripheral oxygen saturation were monitored, and intra- and postoperative arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), and intraoperative peak airway pressure were compared between the 2 groups. Postoperative analgesic consumption was calculated. No significant differences in demographics or preoperative data were noted between the 2 groups. PaO2 values 10 minutes after OLV onset and 10 minutes after the end of OLV were increased significantly in the NS group compared with those in the SHS group (p < 0.05). PaO2 values after 10 minutes of OLV in the NS and SHS groups were 285.5 ± 90 mmHg and 186.7 ± 66 mmHg, respectively. PaO2 values after OLV termination in the NS and SHS groups were 365.8 ± 58 mmHg and 283.6 ± 64 mmHg (p < 0.05), respectively. PaCO2 values 10 minutes after OLV onset, 10 minutes after the end of OLV, at the end of surgery, and upon arrival in the intermediate care unit were significantly different between the 2 groups (p < 0.05). CONCLUSION: The present study demonstrated that during OLV, patients exposed to SHS exhibited significantly lower arterial oxygen pressure compared with nonsmokers. Arterial carbon dioxide values were increased significantly in SHS-exposed patients. Morphine consumption for postoperative analgesia also was increased in patients exposed to SHS compared with that in nonsmokers.

Intraoperative Transesophageal Echocardiography During Cardiovascular Surgery in China.

OBJECTIVE: To perform a comprehensive nationwide survey of more than 90% of all cardiovascular hospitals in China to assess the current 2018 status of transesophageal echocardiography (TEE) equipment, operating physicians, education, impact on surgery, and reimbursement. DESIGN: In this nationwide survey, 716 cardiovascular hospitals in mainland China were included. A 15-question electronic survey was sent to these hospitals and the data were received directly from the questionnaire website for analysis. SETTING: Cardiovascular hospitals in mainland China. PARTICIPANTS: Departments of anesthesiology in cardiovascular hospitals in mainland China. INTERVENTIONS: Answer a 15-question survey. MEASUREMENTS AND MAIN RESULTS: About 90% of hospitals have acquired machines to perform TEEs with most of the machines controlled by the ultrasound department. Anesthesiologists performed intraoperative TEEs in 45% of the hospitals, but only 15% of the hospitals have anesthesiologists who have met the basic TEE training requirements. Most anesthesiologists (68%) believed TEE significantly contributed to patient care during cardiovascular surgeries. The overwhelming majority of surveyed hospital staff (93%) stated that they were planning to continue or start intraoperative TEE examinations in the future. CONCLUSION: Many hospitals in China have acquired equipment to perform intraoperative TEE examinations during cardiovascular surgeries. However, the number of anesthesiologists who can perform TEEs independently still is not adequate. Standardized trainings, a formal certification process, and governmental payment model changes must be provided to ensure high-quality TEE services and better surgical outcomes in China.

The role of intraoperative parameters on predicting laparoscopic abdominal surgery associated acute kidney injury.

BACKGROUND: Laparoscopic abdominal surgery has been widely used to reduce the length of hospital stay and complications from open abdominal surgery. During the operation, the creation of pneumoperitoneum is used for better visualization of the operating field. However, the effect of pneumoperitoneum on kidney function is unknown. We aimed to identify risk factors and predictors associated with AKI development following laparoscopic abdominal surgery. METHODS: A single-center prospective cohort study of laparoscopic abdominal surgery patients between June 2012 and December 2013. Acute kidney injury (AKI) was identified by Kidney Disease Improving Global Outcome (KDIGO) criteria. Urinary neutrophil gelatinase associated lipocalin (uNGAL) was measured on the first 3 days after surgery as a surrogate marker of AKI. RESULTS: Of the 64 patients, 23 (35%) developed postoperative AKI. The mean age, initial blood pressure, and initial glomerular filtration rate were not different between AKI and non-AKI groups. Inflation time and exposure index were significantly higher in the AKI group compared to non-AKI group (192.0 vs 151.1 min, p = 0.045, and 2325.9 vs 1866.1 mmHg-minutes, p = 0.035). Operation time, mean intra-abdominal pressure, duration of intraoperative hypotension, amount of blood loss and intravenous fluid were not different between groups. In multivariable analysis adjusted for age, diabetes, baseline estimated glomerular filtration rate, and type of operation (urological surgery), exposure index was significantly associated with postoperative AKI, with odds ratio (95% CI) 1.47 (1.05-2.04), p = 0.024. By combining the intraoperative parameters with clinical model the area under the receiver operating characteristic curve was 0.71 (95% CI 0.58-0.84). CONCLUSIONS: AKI was a common condition in laparoscopic abdominal surgery. Exposure index has been proposed as a novel predictor of laparoscopic abdominal surgery associated AKI.

Emerging Intraoperative Imaging Modalities to Improve Surgical Precision.

Intraoperative imaging (IOI) is performed to guide delineation and localization of regions of surgical interest. While oncological surgical planning predominantly utilizes x-ray computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US), intraoperative guidance mainly remains on surgeon interpretation and pathology for confirmation. Over the past decades however, intraoperative guidance has evolved significantly with the emergence of several novel imaging technologies, including fluorescence-, Raman, photoacoustic-, and radio-guided approaches. These modalities have demonstrated the potential to further optimize precision in surgical resection and improve clinical outcomes for patients. Not only can these technologies enhance our understanding of the disease, they can also yield large imaging datasets intraoperatively that can be analyzed by deep learning approaches for more rapid and accurate pathological diagnosis. Unfortunately, many of these novel technologies are still under preclinical or early clinical evaluation. Organizations like the Intra-Operative Imaging Study Group of the European Society for Molecular Imaging (ESMI) support interdisciplinary interactions with the aim to improve technical capabilities in the field, an approach that can succeed only if scientists, engineers, and physicians work closely together with industry and regulatory bodies to resolve roadblocks to clinical translation. In this review, we provide an overview of a variety of novel IOI technologies, discuss their challenges, and present future perspectives on the enormous potential of IOI for oncological surgical navigation.

Lack of Association Between Levels and Length of Intraoperative Controlled Hypotension and Acute Kidney Injury in Total Hip Arthroplasty Patients Receiving Neuraxial Anesthesia.

BACKGROUND AND OBJECTIVES: Previous research suggests that increased duration and lower levels of intraoperative hypotension (IOH) are associated with postoperative acute kidney injury (AKI). However, this association has not been evaluated in the context of intraoperative controlled hypotension (IOCH), a practice that has been linked in the past to improved outcomes with respect to blood loss and transfusion needs. This study aimed to investigate whether IOCH is associated with postoperative AKI among total hip arthroplasty patients at an institution where this technique is commonly practiced. METHODS: We performed a retrospective cohort study of 2431 unilateral total hip arthroplasty patients who received IOCH under neuraxial anesthesia as well as invasive arterial monitoring between March 2016 and January 2017. Multiple logistic regression was used to compute the adjusted odds ratios of postoperative AKI, adjusting for covariates including duration of intraoperative mean arterial pressure of less than 60 mm Hg. Sensitivity analyses also considered the effects of IOH defined at mean arterial pressure of less than 55 and less than 65 mm Hg. RESULTS: Acute kidney injury occurred in 45 (1.85%) of the 2431 patients in this cohort. Longer duration of hypotension was not associated with increased odds of postoperative AKI. Preexisting differences, such as compromised renal function, best predicted increased odds of AKI. CONCLUSIONS: In this study, AKI was rare. We found a lack of association between IOH and postoperative AKI in a setting where neuraxial anesthesia-facilitated IOCH is routinely practiced. Therefore, it seems prudent for future research and clinical guidelines to consider the distinction between inadvertent and controlled hypotension.

Defining an Intraoperative Hypotension Threshold in Association with Stroke in Cardiac Surgery.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Stroke is a leading cause of morbidity, mortality, and disability in patients undergoing cardiac surgery. Identifying modifiable perioperative stroke risk factors may lead to improved patient outcomes. The association between the severity and duration of intraoperative hypotension and postoperative stroke in patients undergoing cardiac surgery was evaluated. METHODS: A retrospective cohort study was conducted of adult patients who underwent cardiac surgery requiring cardiopulmonary bypass at a tertiary center between November 1, 2009, and March 31, 2015. The primary outcome was postoperative ischemic stroke. Intraoperative hypotension was defined as the number of minutes spent within mean arterial pressure bands of less than 55, 55 to 64, and 65 to 74 mmHg before, during, and after cardiopulmonary bypass. The association between stroke and hypotension was examined by using logistic regression with propensity score adjustment. RESULTS: Among the 7,457 patients included in this analysis, 111 (1.5%) had a confirmed postoperative diagnosis of stroke. Stroke was strongly associated with sustained mean arterial pressure of less than 64 mmHg during cardiopulmonary bypass (adjusted odds ratio 1.13; 95% CI, 1.05 to 1.21 for every 10 min of mean arterial pressure between 55 and 64 mmHg; adjusted odds ratio 1.16; 95% CI, 1.08 to 1.23 for every 10 min of mean arterial pressure less than 55 mmHg). Other factors that were independently associated with stroke were older age, hypertension, combined coronary artery bypass graft/valve surgery, emergent operative status, prolonged cardiopulmonary bypass duration, and postoperative new-onset atrial fibrillation. CONCLUSIONS: Hypotension is a potentially modifiable risk factor for perioperative stroke. The study's findings suggest that mean arterial pressure may be an important intraoperative therapeutic hemodynamic target to reduce the incidence of stroke in patients undergoing cardiopulmonary bypass.

Comparing the efficacy of shunting approaches and cerebral monitoring during carotid endarterectomy using a national database.

OBJECTIVE: Carotid endarterectomy practice patterns, including the use of shunts and cerebral monitoring techniques, are typically surgeon-dependent and differ greatly on a national level. Prior literature evaluating these techniques is often underpowered for detecting variations in low-frequency outcomes. The purpose of this study was to evaluate current carotid endarterectomy practice patterns and to allow comparison across surgical approaches using a large national database. METHODS: We divided carotid cases entered into the Vascular Quality Initiative database between October 2012 and April 2015 into routine shunting, selective shunting, and never shunting cohorts, excluding endarterectomies performed with concomitant procedures and those with incomplete information on the use of a shunt. The selective group was subdivided into cases with awake, electroencephalography, and stump pressure monitoring. We evaluated differences in practice patterns and compared rates of stroke, death, return to the operating room, reperfusion injury, and re-exploration after closure across these groups. Multivariate logistic regression models adjusting for risk factors were used to identify predictors of each outcome. RESULTS: Between October 2012 and April 2015, there were a total of 28,457 endarterectomies included in our analysis, of which 14,128 involved routine shunting, 1740 involved never shunting, and 12,489 involved selective shunting. Of the selective cases, 6144 involved electroencephalography monitoring, 2310 involved stump pressure monitoring, and 2052 involved awake monitoring. Unadjusted rates of in-hospital death and stroke were 0.30% (95% confidence interval [CI], 0.21-0.39) and 0.78% (95% CI, 0.64-0.93) for routine shunting and 0.22% (95% CI, 0.14-0.31) and 0.91% (95% CI, 0.75-1.08) for selective shunting, respectively. The unadjusted rate of in-hospital death was lower in the awake monitoring group than in the routine shunting group (0.05% vs 0.30%; P = .037). After adjustment for patient risk factors, the multivariate models showed no difference in rates of any primary outcomes among the groups, although there was a shorter postoperative length of stay for the awake monitoring group compared with the routine shunting group (1.55 days vs 2.00 days, respectively; P < .01). CONCLUSIONS: Analysis of the Vascular Quality Initiative registry shows equivalent unadjusted rates of in-hospital death and stroke across different approaches to shunting and cerebral monitoring with the exception of the awake monitoring group, which has lower unadjusted mortality compared with the routine shunting group. In the risk-adjusted analysis, however, there are no differences across any of the groups. Given the clinical equivalence of approaches to shunting and cerebral monitoring, further work should evaluate the relative cost of these techniques.

Model-based directional analysis of cardiovascular variability identifies patients developing atrial fibrillation after coronary artery bypass grafting.

BACKGROUND: Postoperative atrial fibrillation (AF) might be favored by cardiovascular control impairment. We hypothesize that cardiovascular regulation indexes derived from directional model-based analysis of the spontaneous fluctuations of heart period (HP) and systolic arterial pressure (SAP) can identify subjects at risk to develop AF after coronary artery bypass graft (CABG) surgery. METHODS: Beat-to-beat HP and SAP series were derived from electrocardiogram (ECG) and invasive arterial pressure recorded for 5 min just before CABG surgery in conscious condition. The group comprised subjects who did develop AF (AF, n = 37, 71 ±â€¯8 years, 27 males) or did not (noAF, n = 92, 65 ±â€¯10 years, 85 males). From HP and SAP variabilities we computed classical time-domain, spectral, cross-spectral and complexity indexes characterizing autonomic function and cardiac baroreflex control. Moreover, we performed model-based directional analysis assessing the gain and strength of the relations from SAP to HP along cardiac baroreflex feedback and from HP to SAP along the feedforward pathway while disambiguating the effect of respiration as estimated from respiratory-related ECG modulations. RESULTS: Classical HP and SAP variability indexes and baroreflex sensitivity could not separate AF from noAF individuals. Causality markers, and more specifically, the strength of the dynamical interactions from SAP to HP and vice versa, could distinguish the two groups: indeed, AFs have a lower degree of association from SAP to HP and vice versa. CONCLUSIONS: An impairment of the feedforward and feedback arms of the HP-SAP closed loop relation predisposes subjects undergoing CABG surgery to develop postoperative AF. PERSPECTIVES: Competency in medical knowledge: Atrial fibrillation (AF) is a frequent complication after coronary artery bypass graft (CABG) surgery lengthening hospitalization duration and increasing healthcare system costs. Translational outlook 1: CABG patients who developed AF had a less preserved cardiovascular interactions due to less active physiological control mechanisms as resulting from the lower degree of dependence of systolic arterial pressure on heart period and vice versa before CABG surgery. Translational outlook 2: Cardiovascular control markers improve stratification of the AF risk after CABG surgery above and beyond more traditional demographic and clinical indexes.

A decrease in blood pressure is associated with unfavorable outcome in patients undergoing thrombectomy under general anesthesia.

BACKGROUND: Up to two-thirds of patients are either dependent or dead 3 months after thrombectomy for acute ischemic stroke (AIS). Loss of cerebral autoregulation may render patients with AIS vulnerable to decreases in mean arterial pressure (MAP). OBJECTIVE: To determine whether a fall in MAP during intervention under general anesthesia (GA) affects functional outcome. METHODS: This subgroup analysis included patients from the MR CLEAN trial treated with thrombectomy under GA. The investigated variables were the difference between MAP at baseline and average MAP during GA (ΔMAP) as well as the difference between baseline MAP and the lowest MAP during GA (ΔLMAP). Their association with a shift towards better outcome on the modified Rankin Scale (mRS) after 90 days was determined using ordinal logistic regression with adjustment for prognostic baseline variables. RESULTS: Sixty of the 85 patients treated under GA in MR CLEAN had sufficient anesthetic information available for the analysis. A greater ΔMAP was associated with worse outcome (adjusted common OR (acOR) 0.95 per point mm Hg, 95% CI 0.92 to 0.99). An average MAP during GA 10 mm Hg lower than baseline MAP constituted a 1.67 times lower odds of a shift towards good outcome on the mRS. For ΔLMAP this association was not significant (acOR 0.97 per mm Hg, 95% CI 0.94 to 1.00, p=0.09). CONCLUSIONS: A decrease in MAP during intervention under GA compared with baseline is associated with worse outcome. TRIAL REGISTRATION NUMBER: NTR1804; ISRCTN10888758; post-results.