Platelet Biomarkers in Patients with Atherosclerotic Extracranial Carotid Artery Stenosis: A Systematic Review.

OBJECTIVE: The aim was to enhance understanding of the role of platelet biomarkers in the pathogenesis of vascular events and risk stratifying patients with asymptomatic or symptomatic atherosclerotic carotid stenosis. DATA SOURCES: Systematic review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. REVIEW METHODS: A systematic review collated data from 1975 to 2020 on ex vivo platelet activation and platelet function/reactivity in patients with atherosclerotic carotid stenosis. RESULTS: Forty-three studies met the inclusion criteria; the majority included patients on antiplatelet therapy. Five studies showed increased platelet biomarkers in patients with ≥ 30% asymptomatic carotid stenosis (ACS) vs. controls, with one neutral study. Preliminary data from one study suggested that quantification of "coated platelets" in combination with stenosis severity may aid risk stratification in patients with ≥ 50% - 99% ACS. Platelets were excessively activated in patients with ≥ 30% symptomatic carotid stenosis (SCS) vs. controls (≥ 11 positive studies and one neutral study). Antiplatelet-High on Treatment Platelet Reactivity (HTPR), previously called "antiplatelet resistance", was observed in 23% - 57% of patients on aspirin, with clopidogrel-HTPR in 25% - 100% of patients with ≥ 50% - 99% ACS. Aspirin-HTPR was noted in 9.5% - 64% and clopidogrel-HTPR in 0 - 83% of patients with ≥ 50% SCS. However, the data do not currently support the use of ex vivo platelet function/reactivity testing to tailor antiplatelet therapy outside of a research setting. Platelets are excessively activated (n = 5), with increased platelet counts (n = 3) in recently symptomatic vs. asymptomatic patients, including those without micro-emboli on transcranial Doppler (TCD) monitoring (n = 2). Most available studies (n = 7) showed that platelets become more reactive or activated following carotid endarterectomy or stenting, either as an acute phase response to intervention or peri-procedural treatment. CONCLUSION: Platelets are excessively activated in patients with carotid stenosis vs. controls, in recently symptomatic vs. asymptomatic patients, and may become activated/hyper-reactive following carotid interventions despite commonly prescribed antiplatelet regimens. Further prospective multicentre studies are required to determine whether models combining clinical, neurovascular imaging, and platelet biomarker data can facilitate optimised antiplatelet therapy in individual patients with carotid stenosis.

The Safety and Feasibility of Transesophageal Echocardiography in Patients With Esophageal Stricture.

OBJECTIVES: Expert guidelines consistently list esophageal stricture (ES) as a contraindication to the performance of transesophageal echocardiography (TEE), although anecdotally the authors are aware of patients with ES undergoing TEE without apparent complication. Therefore the authors sought to determine the outcomes of patients with ES who had undergone TEE at their institution. DESIGN: Single-center, retrospective review. SETTING: Academic medical center (clinic and affiliated hospital). PARTICIPANTS: Patients with documented ES who also underwent TEE. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In a 10-year period, 1,083 TEE reports were generated for 823 patients who had a diagnosis of ES. One case of esophageal perforation occurred (1/1,083 examination reports [0.09%]) in an 85-year-old male with gastroesophageal reflux disease-related ES who had undergone esophageal dilation the same day as the TEE. In 17.2% of the TEE reports reviewed, changes to the conduct of the examination occurred, such as use of a pediatric probe or avoidance of transgastric imaging. In 8% of reviewed examinations, procedural difficulty was recorded. CONCLUSIONS: Patients with nonmalignant ES commonly present for TEE (>100 per year, on average, at the authors' institution). Severe TEE-related esophageal injury rarely occurred in patients with ES. However, changes to the conduct of the TEE examination and procedural difficulty were not infrequent in this group. Clinicians contemplating TEE in patients with ES should prepare for the possibility of altered examination conduct and possible procedural difficulty.

Antinausea Protocol Reduces Hospital Length of Stay for Laparoscopic Nissen Fundoplication.

OBJECTIVE: The perioperative course of patients undergoing laparoscopic Nissen fundoplication (LNF) was reviewed to determine whether the use of a new treatment protocol consisting of total intravenous anesthesia (TIVA) plus triple antiemetic therapy was associated with shorter hospital length of stay (HLOS). DESIGN: Retrospective cohort. SETTING: Single academic center. PARTICIPANTS: The study comprised 448 patients. Fifty-four patients undergoing LNF who received TIVA were compared with 394 who received standard inhalational anesthesia (non-TIVA) between January 2010 and June 2017. INTERVENTIONS: Patients who received TIVA were compared with those who received non-TIVA. MEASUREMENTS AND MAIN RESULTS: In multivariate analysis, TIVA was significantly associated with reduced HLOS (odds ratio 2.91, 95% confidence interval 1.47-5.78) and a 7.8% reduction in cost of care (p < 0.01). Female sex, length of surgery, and older age all were negatively associated with length of stay. The association between the use of TIVA and reduced HLOS and institutional cost was compared using univariate and multivariate analyses. CONCLUSIONS: The use of TIVA in patients undergoing uncomplicated LNF shortens HLOS and is associated with reduced cost of care. This study illustrates that communication among surgeons and anesthesiologists results in improved patient care.

Comparison of the efficacy of two doses of dexmedetomidine in attenuating the hemodynamic response to intubation in patients undergoing elective cardiac surgery: A randomized double-blinded study.

BACKGROUND AND AIMS: Transient tachycardia and hypertension associated with laryngoscopy and intubation may be hazardous to patients presenting for cardiac surgery. The α 2 agonist dexmedetomidine may blunt this stress response, but the optimal dose which will accomplish this without causing hypotension and bradycardia is not well established. The primary objective of this study was to compare the efficacy of two doses of dexmedetomidine (0.5 and 1 µg/kg) as a 15 min infusion in attenuating the hemodynamic stress response to laryngoscopy and endotracheal intubation in elective cardiac surgery. MATERIAL AND METHODS: Seventy six patients scheduled for elective cardiac surgery received a single preoperative dose of dexmedetomidine of either 0.5 µg/kg (low dose) or 1 µg/kg (high dose) as a 15-min infusion prior to induction. The hemodynamic response to laryngoscopy and endotracheal intubation (heart rate, systolic blood pressure, mean arterial pressure, and diastolic blood pressure) were recorded at different times. Independent sample t-test, Chi-square test of association, and repeated measures analysis of variance were used to analyze the collected data. RESULTS: The incidence of hypertension following intubation was significantly more in the low-dose group. Administration of 1 µg/kg dexmedetomidine was not accompanied by hypotension or bradycardia. CONCLUSION: Dexmedetomidine in a dose of 1 µg/kg is more effective than 0.5 µg/kg for attenuation of hemodynamic stress response to intubation in cardiac surgery. A more graded increase in the dose of dexmedetomidine may lead to an optimum dose in attenuating the hemodynamic response to intubation.

Hospital Rating Systems and Implications For Patient Travel to Better-rated Hospitals.

Publicly reported hospital ratings aim to encourage transparency, spur quality improvement, and empower patient choice. Travel burdens may limit patient choice, particularly for older adults (aged 65 years and more) who receive most medical care. For 3 major hospital ratings systems, we estimated travel burden as the additional 1-way travel distance to receive care at a better-rated hospital.Distances were estimated from publicly available data from the US Census, US News Top Hospitals, Society of Thoracic Surgeons composite rating for coronary artery bypass grafting (STS-CABG), and Centers for Medicare and Medicaid Services Hospital Consumer Assessment of Healthcare Providers and Services (HCAHPS).Hospitals were rated for HCAHPS (n = 4656), STS-CABG (n = 470), and US News Top Hospitals (n = 15). Older adults were commonly located within 25 miles of their closest HCAHPS hospital (89.6%), but less commonly for STS-CABG (62.9%). To receive care at a better-rated hospital, travel distances commonly exceeded 25 miles: HCAHPS (39.2%), STS-CABG (62.7%), and US News Top Hospital (85.2%). Additional 1-way travel distances exceeded 25 miles commonly: HCAHPS (23.7%), STS-CABG (36.7%), US News Top Hospitals (81.8%).Significant travel burden is common for older adults seeking "better" care and is an important limitation of current hospital ratings for empowering patient choice.

Risk Factors and Clinical Outcomes Associated with Perioperative Transfusion-associated Circulatory Overload.

BACKGROUND: Transfusion-associated circulatory overload remains underappreciated in the perioperative environment. The authors aimed to characterize risk factors for perioperative transfusion-associated circulatory overload and better understand its impact on patient-important outcomes. METHODS: In this case-control study, 163 adults undergoing noncardiac surgery who developed perioperative transfusion-associated circulatory overload were matched with 726 transfused controls who did not develop respiratory complications. Univariate and multivariable logistic regression analyses were used to evaluate potential risk factors for transfusion-associated circulatory overload. The need for postoperative mechanical ventilation, lengths of intensive care unit and hospital stay, and mortality were compared. RESULTS: For this cohort, the mean age was 71 yr and 56% were men. Multivariable analysis revealed the following independent predictors of transfusion-associated circulatory overload: emergency surgery, chronic kidney disease, left ventricular dysfunction, previous ß-adrenergic receptor antagonist use, isolated fresh frozen plasma transfusion (vs. isolated erythrocyte transfusion), mixed product transfusion (vs. isolated erythrocyte transfusion), and increasing intraoperative fluid administration. Patients who developed transfusion-associated circulatory overload were more likely to require postoperative mechanical ventilation (73 vs. 33%; P < 0.001) and experienced prolonged intensive care unit (11.1 vs. 6.5 days; P < 0.001) and hospital lengths of stay (19.9 vs. 9.6 days; P < 0.001). Survival was significantly reduced (P < 0.001) in transfusion recipients who developed transfusion-associated circulatory overload (1-yr survival 72 vs. 84%). CONCLUSIONS: Perioperative transfusion-associated circulatory overload was associated with a protracted hospital course and increased mortality. Efforts to minimize the incidence of transfusion-associated circulatory overload should focus on the judicious use of intraoperative blood transfusions and nonsanguineous fluid therapies, particularly in patients with chronic kidney disease, left ventricular dysfunction, chronic ß-blocker therapy, and those requiring emergency surgery.

Anesthesia Care Transitions and Risk of Postoperative Complications.

BACKGROUND: A patient undergoing surgery may receive anesthesia care from several anesthesia providers. The safety of anesthesia care transitions has not been evaluated. Using unconditional and conditional multivariable logistic regression models, we tested whether the number of attending anesthesiologists involved in an operation was associated with postoperative complications. METHODS: In a cohort of patients undergoing elective colorectal surgical in an academic tertiary care center with a stable anesthesia care team model participating in the American College of Surgeons National Surgical Quality Improvement Program, using unconditional and conditional multivariable logistic regression models, we tested adjusted associations between numbers of attending anesthesiologists and occurrence of death or a major complication (acute renal failure, bleeding that required a transfusion of 4 units or more of red blood cells within 72 hours after surgery, cardiac arrest requiring cardiopulmonary resuscitation, coma of 24 hours or longer, myocardial infarction, unplanned intubation, ventilator use for 48 hours or more, pneumonia, stroke, wound disruption, deep or organ-space surgical-site infection, superficial surgical-site infection, sepsis, septic shock, systemic inflammatory response syndrome). RESULTS: We identified 927 patients who underwent elective colectomy of comparable surgical intensity. In all, 71 (7.7%) patients had major nonfatal complications or death. One anesthesiologist provided care for 530 (57%) patients, 2 anesthesiologists for 287 (31%), and 3 or more for 110 (12%). The number of attending anesthesiologists was associated with increased odds of postoperative complication (unadjusted odds ratio [OR] = 1.52, 95% confidence interval [CI] 1.18-1.96, P = 0.0013; adjusted OR = 1.44, 95% CI 1.09-1.91, P = 0.0106). In sensitivity analyses, occurrence of a complication was significantly associated with the number of in-room providers, defined as anesthesia residents and nurse anesthetists (adjusted OR = 1.39, 95% CI 1.01-1.92, P = 0.0446) and for all anesthesia providers (adjusted OR = 1.58, 95%CI 1.20-2.08, P = 0.0012). Findings persisted across multiple, alternative adjustments, sensitivity analyses, and conditional logistic regression with matching on operative duration. CONCLUSIONS: In our study, care by additional attending anesthesiologists and in-room providers was independently associated with an increased odds of postoperative complications. These findings challenge the assumption that anesthesia transitions are care neutral and not contributory to surgical outcomes.

Definitive airway management of patients presenting with a pre-hospital inserted King LT(S)-D laryngeal tube airway: a historical cohort study.

PURPOSE: The King LT(S)-D laryngeal tube (King LT) has gained popularity as a bridge airway for pre-hospital airway management. In this study, we retrospectively reviewed the use of the King LT and its associated airway outcomes at a single Level 1 trauma centre. METHODS: The data on all adult patients presenting to the Mayo Clinic in Rochester, Minnesota with a King LT in situ from July 1, 2007 to October 10, 2012 were retrospectively evaluated. Data collected and descriptively analyzed included patient demographics, comorbidities, etiology of respiratory failure, airway complications, subsequent definitive airway management technique, duration of mechanical ventilation, and status at discharge. RESULTS: Forty-eight adult patients met inclusion criteria. The most common etiology for respiratory failure requiring an artificial airway was cardiac arrest [28 (58%) patients] or trauma [9 (19%) patients]. Four of the nine trauma patients had facial trauma. Surgical tracheostomy was the definitive airway management technique in 14 (29%) patients. An airway exchange catheter, direct laryngoscopy, and video laryngoscopy were used in 11 (23%), ten (21%), and ten (21%) cases, respectively. Seven (78%) of the trauma patients underwent surgical tracheostomy compared with seven (18%) of the medical patients. Adverse events associated with King LT use occurred in 13 (27%) patients, with upper airway edema (i.e., tongue engorgement and glottic edema) being most common (19%). CONCLUSION: In this study of patients presenting to a hospital with a King LT, the majority of airway exchanges required an advanced airway management technique beyond direct laryngoscopy. Upper airway edema was the most common adverse observation associated with King LT use.

Characterizing the epidemiology of postoperative transfusion-related acute lung injury.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related death in the United States; however, it remains poorly characterized in surgical populations. To better inform perioperative transfusion practice, and to help mitigate perioperative TRALI, the authors aimed to better define its epidemiology before and after TRALI mitigation strategies were introduced. METHODS: This retrospective cohort study examined outcomes of adult patients undergoing noncardiac surgery with general anesthesia who received intraoperative transfusions during 2004 (n = 1,817) and 2011 (n = 1,562). The demographics and clinical characteristics of transfusion recipients, blood transfusion descriptors, and combined TRALI/possible TRALI incidence rates were evaluated. Univariate analyses were used to compare associations between patient characteristics, transfusion details, and TRALI mitigation strategies with TRALI/possible TRALI incidence rates in a before-and-after study design. RESULTS: The incidence of TRALI/possible TRALI was 1.3% (23 of 1,613) in 2004 versus 1.4% (22 of 1,562) in 2011 (P = 0.72), with comparable overall rates in males versus females (1.4% [23 of 1,613] vs. 1.2% [22 of 1,766]) (P = 0.65). Overall, thoracic (3.0% [4 of 133]), vascular (2.7% [10 of 375]), and transplant surgeries (2.2% [4 of 178]) carried the highest rates of TRALI/possible TRALI. Obstetric and gynecologic surgical patients had no TRALI episodes. TRALI/possible TRALI incidence increased with larger volumes of blood product transfused (P < 0.001). CONCLUSIONS: Perioperative TRALI/possible TRALI is more common than previously reported and its risk increases with greater volumes of blood component therapies. No significant reduction in the combined incidence of TRALI/possible TRALI occurred between 2004 and 2011, despite the introduction of TRALI mitigation strategies. Future efforts to identify specific risk factors for TRALI/possible TRALI in surgical populations may reduce the burden of this life-threatening complication.

Characterizing the epidemiology of perioperative transfusion-associated circulatory overload.

BACKGROUND: Transfusion-associated circulatory overload (TACO) is a leading cause of transfusion-related fatalities, but its incidence and associated patient and transfusion characteristics are poorly understood. To inform surgical transfusion practice and to begin mitigating perioperative TACO, the authors aimed to define its epidemiology. METHODS: In this retrospective cohort study, the medical records of adult patients undergoing noncardiac surgery with general anesthesia during 2004 or 2011 and receiving intraoperative transfusions were screened using an electronic algorithm for identification of TACO. Those patients who were screened as high probability for TACO underwent rigorous manual review. Univariate and multivariate analyses evaluated associations between patient and transfusion characteristics with TACO rates in a before-and-after study design. RESULTS: A total of 2,162 and 1,908 patients met study criteria for 2004 and 2011, respectively. The incidence of TACO was 5.5% (119 of 2,162) in 2004 versus 3.0% (57 of 1,908) in 2011 (P < 0.001), with comparable rates for men (4.8% [98 of 2,023]) and women (3.8% [78 of 2,047]) (P = 0.09). Overall, vascular (12.1% [60 of 497]), transplant (8.8% [17 of 193]), and thoracic surgeries (7.2% [10 of 138]) carried the highest TACO rates. Obstetric and gynecologic patients had the lowest rate (1.4% [4 of 295]). The incidence of TACO increased with volume transfused, advancing age, and total intraoperative fluid balance (all P < 0.001). CONCLUSIONS: The incidence of perioperative TACO is similar to previous estimates in nonsurgical populations. There was a reduction in TACO rate between 2004 and 2011, with incidence patterns remaining comparable in subgroup analyses. Future efforts exploring risk factors for TACO may guide preventive or therapeutic interventions, helping to further mitigate this transfusion complication.

Effect of Levosimendan on Diastolic Function in Patients Undergoing Coronary Artery Bypass Grafting: A Comparative Study.

PURPOSE: To compare the efficacy of levosimendan with nitroglycerin in patients with isolated diastolic dysfunction undergoing coronary artery bypass grafting. PROCEDURE: Thirty patients with isolated diastolic dysfunction undergoing on-pump coronary artery bypass grafting were randomized into 2 groups receiving levosimendan or nitroglycerin infusion. The infusion was started before sternotomy and continued in the postoperative period. Perioperatively, diastolic function was serially evaluated at 3 different time points using echocardiography. N-terminal fragment of pro-B-natriuretic peptide (NT-proBNP) levels were measured in both the groups. RESULTS: There was a significant improvement in diastolic function as measured by isovolumic relaxation time (P = 0.0001, P = 0.001) and deceleration time (P = 0.0001, P = 0.0001) in the levosimendan group from the baseline in patients with impaired relaxation. Similarly, tissue Doppler imaging also revealed an improvement from the baseline in patients with a pseudonormal pattern (P = 0.018, P = 0.001). Furthermore, there was a significant improvement in the above parameters when compared with the nitroglycerin group. The NT-proBNP levels also demonstrated a similar pattern between the 2 groups (P = 0.03, P = 0.02) when levosimendan was compared with nitroglycerin in patients with a pseudonormal pattern on echocardiography. CONCLUSIONS: Levosimendan is superior to nitroglycerin in improving diastolic function irrespective of coronary revascularization.

Preoperative statin administration does not protect against early postoperative acute respiratory distress syndrome: a retrospective cohort study.

BACKGROUND: Statins have been shown to possess antiinflammatory and immunomodulatory effects. In this study, we sought to determine if preoperative statin therapy is associated with a reduced frequency of postoperative acute respiratory distress syndrome (ARDS) in surgical populations at increased risk of developing ARDS. METHODS: We performed a retrospective cohort evaluation of the association between preoperative statin therapy and early postoperative ARDS in patients undergoing elective high-risk thoracic and aortic vascular surgery. The association between preoperative statin therapy and postoperative ARDS was assessed using propensity-adjusted analyses to control for indication bias and confounding factors. RESULTS: Of 1845 patients, 722 were receiving preoperative statin therapy. One hundred twenty patients developed postoperative ARDS. Frequencies of ARDS among those receiving statin therapy versus those who were not was 7.2% and 6.1%, respectively (OR = 1.20; 95% CI, 0.83-1.75; P = 0.330). Neither the stratified propensity score analysis (pooled OR 0.93; 95% CI, 0.60-1.43) nor matched analysis (OR = 0.78; 95% CI, 0.48-1.27) identified a statistically significant association between preoperative statin administration and postoperative ARDS. When compared to matched controls, patients who developed postoperative ARDS did not differ in mortality (7.7% vs 8.8%, P = 0.51), hospital length of stay (21 days vs 15 days, P = 0.21), or ventilator-free days (24 days vs 25 days, P = 0.62). CONCLUSIONS: In patients undergoing high-risk surgery, preoperative statin therapy was not associated with a statistically significant reduction in postoperative ARDS. These results do not support the use of statins as prophylaxis against ARDS in patients undergoing high-risk surgery.

Perioperative endothelin levels in patients undergoing intracardiac repair for tetralogy of Fallot.

BACKGROUND: Endothelin, a pro-inflammatory molecule, had been extensively studied in patients with cardiovascular illness. Impact on the perioperative outcome of patients with cyanotic congenital heart defects is still unknown. In the present study, we report perioperative changes in endothelin levels and their correlation with preoperative factors and clinical outcomes in a group of patients with tetralogy of Fallot (TOF) undergoing definitive repair. METHODOLOGY: 167 patients with TOF undergoing intracardiac repair under cardiopulmonary bypass were studied. Endothelin levels were taken at three different points of time and correlated with different clinical variables. RESULTS: The baseline endothelin level correlated with patients' nutritional status and degree of cyanosis. The magnitude of inflammatory response in the post-cardiopulmonary bypass (post-CPB) period as measured by endothelin level was much higher and correlated more consistently with adverse clinical outcomes in the younger age group. On multivariable analysis, age at operation, preoperative degree of hypoxemia, and endothelin levels were found to be independent predictors of clinical outcomes. CONCLUSIONS: A rise in serum endothelin levels in patients with TOF undergoing definitive repair on CPB, with preoperative severity of cyanosis, nutritional status, and adverse clinical outcomes. The endothelin levels may be monitored to identify patients with cyanosis at an increased risk of exhibiting augmented inflammatory response to CPB.

Improving operating room productivity via parallel anesthesia processing.

PURPOSE: Parallel processing of regional anesthesia may improve operating room (OR) efficiency in patients undergoes upper extremity surgical procedures. The purpose of this paper is to evaluate whether performing regional anesthesia outside the OR in parallel increases total cases per day, improve efficiency and productivity. DESIGN/METHODOLOGY/APPROACH: Data from all adult patients who underwent regional anesthesia as their primary anesthetic for upper extremity surgery over a one-year period were used to develop a simulation model. The model evaluated pure operating modes of regional anesthesia performed within and outside the OR in a parallel manner. The scenarios were used to evaluate how many surgeries could be completed in a standard work day (555 minutes) and assuming a standard three cases per day, what was the predicted end-of-day time overtime. FINDINGS: Modeling results show that parallel processing of regional anesthesia increases the average cases per day for all surgeons included in the study. The average increase was 0.42 surgeries per day. Where it was assumed that three cases per day would be performed by all surgeons, the days going to overtime was reduced by 43 percent with parallel block. The overtime with parallel anesthesia was also projected to be 40 minutes less per day per surgeon. RESEARCH LIMITATIONS/IMPLICATIONS: Key limitations include the assumption that all cases used regional anesthesia in the comparisons. Many days may have both regional and general anesthesia. Also, as a case study, single-center research may limit generalizability. PRACTICAL IMPLICATIONS: Perioperative care providers should consider parallel administration of regional anesthesia where there is a desire to increase daily upper extremity surgical case capacity. Where there are sufficient resources to do parallel anesthesia processing, efficiency and productivity can be significantly improved. ORIGINALITY/VALUE: Simulation modeling can be an effective tool to show practice change effects at a system-wide level.

How to improve the performance of intraoperative risk models: an example with vital signs using the surgical apgar score.

BACKGROUND: Computerized reviews of patient data promise to improve patient care through early and accurate identification of at-risk and well patients. The significance of sampling strategy for patient vital signs data is not known. In the instance of the surgical Apgar score (SAS), we hypothesized that larger sampling intervals would improve the specificity and overall predictive ability of this tool. METHODS: We used electronic intraoperative data from general and vascular surgical patients in a single-institution registry of the American College of Surgeons National Surgical Quality Improvement Program. The SAS, consisting of lowest heart rate, lowest mean arterial blood pressure, and estimated blood loss between incision and skin closure, was calculated using 5 methods: instantaneously and using intervals of of 5 and 10 minutes with and without interval overlap. Major complications including death were assessed at 30 days postoperatively. RESULTS: Among 3000 patients, 272 (9.1%) experienced major complications or death. As the sampling interval increased from instantaneous (shortest) to 10 minutes without overlap (largest), the sensitivity, positive predictive value, and negative predictive value did not change significantly, but significant improvements were noted for specificity (79.5% to 82.9% across methods, P for trend <0.001) and accuracy (76.0% to 79.3% across methods, P for trend <0.01). In multivariate modeling, the predictive utility of the SAS as measured by the c-statistic nearly increased from Δc = +0.012 (P = 0.038) to Δc = +0.021 (P < 0.002) between the shortest and largest sampling intervals, respectively. Compared with a preoperative risk model, the net reclassification improvement and integrated discrimination improvement for the shortest versus largest sampling intervals of the SAS were net reclassification improvement 0.01 (P = 0.8) vs 0.06 (P = 0.02), and for integrated discrimination improvement, they were 0.008 (P < 0.01) vs 0.015 (P < 0.001). CONCLUSIONS: When vital signs data are recorded in compliance with American Society of Anesthesiologists' standards, the sampling strategy for vital signs significantly influences performance of the SAS. Computerized reviews of patient data are subject to the choice of sampling methods for vital signs and may have the potential to be optimized for safe, efficient patient care.

Connecting the dots: rule-based decision support systems in the modern EMR era.

The intensive care unit (ICU) environment is rich in both medical device and electronic medical record (EMR) data. The ICU patient population is particularly vulnerable to medical error or delayed medical intervention both of which are associated with excess morbidity, mortality and cost. The development and deployment of smart alarms, computerized decision support systems (DSS) and "sniffers" within ICU clinical information systems has the potential to improve the safety and outcomes of critically ill hospitalized patients. However, the current generations of alerts, run largely through bedside monitors, are far from ideal and rarely support the clinician in the early recognition of complex physiologic syndromes or deviations from expected care pathways. False alerts and alert fatigue remain prevalent. In the coming era of widespread EMR implementation novel medical informatics methods may be adaptable to the development of next generation, rule-based DSS.

Plasma transfusion is associated with postoperative infectious complications following esophageal resection surgery: a retrospective cohort study.

OBJECTIVE: To examine the association between blood component transfusions and the incidence of major postoperative infections in patients undergoing esophageal resection surgery. DESIGN: Retrospective cohort study. SETTING: Single academic tertiary referral center. PARTICIPANTS: All patients who underwent esophagectomy from 2005 through 2009. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the incidence of major postoperative infection, defined as pneumonia, bloodstream infection, and/or a surgical site infection occurring within 30 days postoperatively. In total, 465 patients were evaluated. One hundred thirty-eight patients (29.7%) received a blood transfusion before the onset of a major postoperative infection or during a similar exposure interval in those with no such complications. Univariate analysis showed a significant association between any blood component transfusion and postoperative infection (transfused v nontransfused 31.9% v 13.2%; odds ratio = 3.1, 95% confidence interval = 1.9-5.0; p < 0.01). This association was lost on multivariate analysis. Subgroup analysis with multivariate adjustment identified a significant association between high plasma volume blood component transfusions and postoperative infection (odds ratio = 4.2, 95% confidence interval = 1.2-15.8; p = 0.03). With multivariate adjustment, red blood cell administration was no longer associated with major postoperative infectious complications. CONCLUSIONS: High plasma volume blood component transfusions were associated with the development of major postoperative infectious complications in patients undergoing esophageal resection surgery. In contrast, red blood cell transfusion was not associated with infectious complications.

Structural and catalytic differences between two FADH(2)-dependent monooxygenases: 2,4,5-TCP 4-monooxygenase (TftD) from Burkholderia cepacia AC1100 and 2,4,6-TCP 4-monooxygenase (TcpA) from Cupriavidus necator JMP134.

2,4,5-TCP 4-monooxygenase (TftD) and 2,4,6-TCP 4-monooxygenase (TcpA) have been discovered in the biodegradation of 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4,6-trichlorophenol (2,4,6-TCP). TcpA and TftD belong to the reduced flavin adenine dinucleotide (FADH(2))-dependent monooxygenases and both use 2,4,6-TCP as a substrate; however, the two enzymes produce different end products. TftD catalyzes a typical monooxygenase reaction, while TcpA catalyzes a typical monooxygenase reaction followed by a hydrolytic dechlorination. We have previously reported the 3D structure of TftD and confirmed the catalytic residue, His289. Here we have determined the crystal structure of TcpA and investigated the apparent differences in specificity and catalysis between these two closely related monooxygenases through structural comparison. Our computational docking results suggest that Ala293 in TcpA (Ile292 in TftD) is possibly responsible for the differences in substrate specificity between the two monooxygenases. We have also identified that Arg101 in TcpA could provide inductive effects/charge stabilization during hydrolytic dechlorination. The collective information provides a fundamental understanding of the catalytic reaction mechanism and the parameters for substrate specificity. The information may provide guidance for designing bioremediation strategies for polychlorophenols, a major group of environmental pollutants.

Effects of Image Quality on the Accuracy Human Pose Estimation and Detection of Eye Lid Opening/Closing Using Openpose and DLib.

OBJECTIVE: The application of computer models in continuous patient activity monitoring using video cameras is complicated by the capture of images of varying qualities due to poor lighting conditions and lower image resolutions. Insufficient literature has assessed the effects of image resolution, color depth, noise level, and low light on the inference of eye opening and closing and body landmarks from digital images. METHOD: This study systematically assessed the effects of varying image resolutions (from 100 × 100 pixels to 20 × 20 pixels at an interval of 10 pixels), lighting conditions (from 42 to 2 lux with an interval of 2 lux), color-depths (from 16.7 M colors to 8 M, 1 M, 512 K, 216 K, 64 K, 8 K, 1 K, 729, 512, 343, 216, 125, 64, 27, and 8 colors), and noise levels on the accuracy and model performance in eye dimension estimation and body keypoint localization using the Dlib library and OpenPose with images from the Closed Eyes in the Wild and the COCO datasets, as well as photographs of the face captured at different light intensities. RESULTS: The model accuracy and rate of model failure remained acceptable at an image resolution of 60 × 60 pixels, a color depth of 343 colors, a light intensity of 14 lux, and a Gaussian noise level of 4% (i.e., 4% of pixels replaced by Gaussian noise). CONCLUSIONS: The Dlib and OpenPose models failed to detect eye dimensions and body keypoints only at low image resolutions, lighting conditions, and color depths. CLINICAL IMPACT: Our established baseline threshold values will be useful for future work in the application of computer vision in continuous patient monitoring.

A homologous series of structures on the surface of SrTiO3(110).

Strontium titanate is seeing increasing interest in fields ranging from thin-film growth to water-splitting catalysis and electronic devices. Although the surface structure and chemistry are of vital importance to many of these applications, theories about the driving forces vary widely. We report here a solution to the 3 x 1 SrTiO(3)(110) surface structure obtained through transmission electron diffraction and direct methods, and confirmed through density functional theory calculations and scanning tunnelling microscopy images and simulations, consisting of rings of six or eight corner-sharing TiO(4) tetrahedra. Further, by changing the number of tetrahedra per ring, a homologous series of n x 1 (n > or = 2) surface reconstructions is formed. Calculations show that the lower members of the series (n < or = 6) are thermodynamically stable and the structures agree with scanning tunnelling microscopy images. Although the surface energy of a crystal is usually thought to determine the structure and stoichiometry, we demonstrate that the opposite can occur. The n x 1 reconstructions are sufficiently close in energy for the stoichiometry in the near-surface region to determine which reconstruction is formed. Our results indicate that the rules of inorganic coordination chemistry apply to oxide surfaces, with concepts such as homologous series and intergrowths as valid at the surface as they are in the bulk.