Effect of geography on the use of ultrafiltration during cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Ultrafiltration (UF) is a common practice during cardiopulmonary bypass (CPB) where it is used as a blood management strategy to reduce red blood cell (RBC) transfusion, minimize adverse effects of hemodilution, and reduce proinflammatory mediators. However, its clinical utilization has been shown to vary throughout the continents. PURPOSE: The purpose of this investigation was to assess the distribution of UF use across the United States. DATA COLLECTION: Data on UF use during cardiac surgery was obtained from a national (United States) perfusion database for adult cardiac procedures performed from January 2016 through December 2018. STUDY SAMPLE: Four geographical regions were established: Northeast (NE), South (SO), Midwest (MW) and West (WE). The primary endpoint was the use of UF with secondary endpoints UF volume, CPB and anesthesia asanguineous volumes, intraoperative allogeneic RBC transfusion, nadir hematocrit and urine output (UO). 92,859 adult cardiac cases from 191 hospitals were reviewed. RESULTS: The NE and the WE had similar usages of UF (59.9% and 59.7% respectively), which were higher than the MW and the SO (38.6% and 34.9%, p < .001). When UF was utilized, the median [IQR] volume removed was highest in the NE (1900 [1200-2800]mL), and similar in all other regions (WE 1500 [850-2400 mL, MW 1500 [900-2300]mL and SO 1500 [950-2200]mL, p < .001. Median total UO was lowest in the NE 400 [210,650]mL vs all other regions (p < .001), and remained so when indexed by patient weight and operative time (NE-0.8 [0.5, 1.3]mL/kg/hour, MW-1.1 [0.7, 1.8] mL/kg/hour, SO-1.3 [0.8, 2.0]mL/kg/hour, WE-1.1 [0.7, 1.3]mL/kg/hour, p < .001. Intraoperative RBC transfusion rate was highest in the SO (21.3%) and WE (20.5%), while similar rates seen in the NE (16.2%) and MW (17.6%), p < .001. CONCLUSIONS: Across the United States there is geographic variation on the use of UF. Further research is warranted to investigate why these practice variations exist and to better understand and determine their reasons for use.

Establishment of a national quality improvement process on oxygen delivery index during cardiopulmonary bypass.

Targeted oxygen delivery during cardiopulmonary bypass (CPB) has received significant attention due to its influence on patient outcomes, especially in mitigating acute kidney injury. While it has gained popularity in select institutions, there remains a gap in establishing it globally across multiple centers. The purpose of this investigation was to describe the development of a quality improvement process of targeted oxygen delivery during CPB across hospitals throughout the United States. A systematic approach to utilize oxygen delivery index (DO2i) as a key performance indicator within hospitals serviced by a national provider of perfusion services. The process included a review of the current literature on DO2i, which yielded a target nadir value (272 mL/min/m2) and an area under the curve (DO2i272AUC) cut off of 632. All data is displayed on a dashboard with results categorized across multiple levels from system-wide to individual clinician performance. From January 2020 through December 2022, DO2i data from 91 hospitals and 11,165 coronary artery bypass graft procedures were collected. During this period the monthly proportion of DO2i measurements above the target nadir DO2i272 ranged from 60.5% to 78.4% with a mean+/-SD of 70.8 +/- 4.2%. Binary logistic regression for the first 7 months following monthly DO2i performance reporting has shown a statistically significant positive linear trend in the probability of achieving the target DO2i272 (p < .001), with a crude increase of approximately 7.8% for DO2i272AUC, and a 73.8% success rate (p < .001). A survey was sent to all individuals measuring oxygen delivery during CPB to assess why a target DO2i272 could not be reached. The two most common responses were an 'inability to improve CPB flow rates' and 'restrictive allogeneic red blood cell transfusion policies'. This study demonstrates that targeting a minimum level of oxygen delivery can serve as a key performance indicator during CPB using a structured quality improvement process.

Linking Patterns of Intraoperative Neuromonitoring (IONM) Alerts to the Odds of a New Postoperative Neurological Deficit: Analysis of 27,808 Cervical Spine Procedures From a National Multi-institutional Database.

STUDY DESIGN/SETTING: Retrospective review of a national multi-institutional database of 27,808 extradural cervical spine procedures performed between January 2017 and May 2021. OBJECTIVE: Characterize intraoperative neuromonitoring alerts by the patterns of modalities and nerves/muscles involved and quantify risk of new-onset neurological deficit for patients with a primary diagnosis of myelopathy, stenosis, or radiculopathy. SUMMARY OF BACKGROUND DATA: Phenotyping alert patterns and linking those patterns with risk is needed to facilitate clinical decision-making. METHODS: Cases with alerts were categorized by patterns of modalities or nerves/muscles involved, and alert status at closure. Unadjusted odds ratios (ORs) for new-onset neurological deficit were calculated. A mixed-effects logistic regression model controlling for demographic and operative factors, with random intercepts to account for clustering in outcomes by surgeon and surgical neurophysiologist was also used to calculate ORs and probabilities of neurological deficit. RESULTS: There was significantly increased risk of a new neurological deficit for procedures involving posterior compared with anterior approaches (OR: 1.82, P=0.001) and procedures involving three levels compared with one (OR: 2.17, P=0.001). Odds of a deficit were lower for patients with radiculopathy compared with myelopathy (OR: 0.69, P=0.058). Compared with cases with no alerts, those with unresolved Spinal Cord alerts were associated with the greatest elevation in risk (OR: 289.05) followed by unresolved C5-6 Nerve Root (OR: 172.7), C5-T1 Nerve Root/Arm (OR: 162.89), C7 Nerve Root (OR:84.2), and C8-T1 Nerve Root alerts (OR:75.49, all P<0.001). Significant reductions in risk were seen for resolved Spinal Cord, C5-6 Nerve Root, and C8-T1 nerve alerts. Overall, unresolved motor evoked potential and somatosensory evoked potential alerts were associated with the greatest elevation in risk (OR:340.92) followed by unresolved motor evoked potential-only (OR:140.6) and unresolved somatosensory evoked potential-Only alerts (OR:78.3, all P<0.001). These relationships were similar across diagnostic cohorts. CONCLUSIONS: Risk elevation and risk mitigation after an intraoperative neuromonitoring alert during surgery is dependent on the type and pattern of alert.

Variation in outcomes with extracorporeal membrane oxygenation in the era of coronavirus: A multicenter cohort evaluation.

Extracorporeal membrane oxygenation (ECMO) is used in critically ill patients with coronavirus disease 2019 (COVID-19) with acute respiratory distress syndrome unresponsive to other interventions. However, a COVID-19 infection may result in a differential tolerance to both medical treatment and ECMO management. The aim of this study was to compare outcomes (mortality, organ failure, circuit complications) in patients on ECMO with and without COVID-19 infection, either by venovenous (VV) or venoarterial (VA) cannulation. This is a multicenter, retrospective analysis of a national database of patients placed on ECMO between May 2020 and January 2022 within the United States. Nine-hundred thirty patients were classified as either Pulmonary (PULM, n = 206), Cardiac (CARD, n = 279) or COVID-19 (COVID, n = 445). Patients were younger in COVID groups: PULM = 48.4 ± 15.8 years versus COVID = 44.9 ± 12.3 years, p = 0.006, and CARD = 57.9 ± 15.4 versus COVID = 46.5 ± 11.8 years, p < 0.001. Total hours on ECMO were greatest for COVID patients with a median support time two-times higher for VV support (365 [101, 657] hours vs 183 [63, 361], p < 0.001), and three times longer for VA support (212 [99, 566] hours vs 70 [17, 159], p < 0.001). Mortality was highest for COVID patients for both cannulation types (VA-70% vs 51% in CARD, p = 0.041, and VV-59% vs PULM-42%, p < 0.001). For VA supported patients hepatic failure was more often seen with COVID patients, while for VV support renal failure was higher. Circuit complications were more frequent in the COVID group as compared to both CARD and PULM with significantly higher circuit change-outs, circuit thromboses and oxygenator failures. Anticoagulation with direct thrombin inhibitors was used more often in COVID compared to both CARD (31% vs 10%, p = 0.002) and PULM (43% vs 15%, p < 0.001) groups. This multicenter observational study has shown that COVID patients on ECMO had higher support times, greater hospital mortality and higher circuit complications, when compared to patients managed for either cardiac or pulmonary lesions.

Variation in survival in patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation: A multi-institutional analysis of 594 consecutive patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation at 49 hospitals within 21 states.

OBJECTIVES: We reviewed 594 consecutive patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation at 49 hospitals within 21 states and examined patient characteristics, treatments, and variation in outcomes over the course of the pandemic. METHODS: A multi-institutional database was used to assess all patients with Coronavirus Disease 2019 cannulated for extracorporeal membrane oxygenation between March 17, 2020, and December 20, 2021, inclusive, and separated from ECMO on or prior to January 14, 2022. Descriptive analysis was stratified by 4 time categories: group A = March 2020 to June 2020, group B = July 2020 to December 2020, group C = January 2021 to June 2021, group D = July 2021 to December 2021. A Bayesian mixed-effects logistic regression was used to assess continuous trends in survival where time was operationalized as the number of days between each patient's cannulation and that of the first patient in March 2020, controlling for multiple variables and risk factors. RESULTS: At hospital discharge, of 594 patients, 221 survived (37.2%) and 373 died. Throughout the study, median age [interquartile range] declined (group A = 51.0 [41.0-60.0] years, group D = 39.0 [32.0-48.0] years, P < .001); median days between Coronavirus Disease 2019 diagnosis and intubation increased (group A = 4.0 [1.0-8.5], group D = 9.0 [5.0-14.5], P < .001); and use of medications (glucocorticoids, interleukin-6 blockers, antivirals, antimalarials) and convalescent plasma fluctuated significantly (all P < .05). Estimated odds of survival varied over the study period with a decline between April 1, 2020, and November 21, 2020 (odds ratio, 0.39, 95% credible interval, 0.18-0.87, probability of reduction in survival = 95.7%), improvement between November 21, 2020, and May 17, 2021 (odds ratio, 1.85, 95% credible interval, 0.86-4.09, probability of improvement = 93.4%), and decline between May 17, 2021, and December 1, 2021 (odds ratio, 0.49, 95% credible interval, 0.19-1.44, probability of decrease = 92.1%). CONCLUSIONS: Survival for patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation has fluctuated during the stages of the pandemic. Minimizing variability by adherence to best practices may refine the optimal use of extracorporeal membrane oxygenation in a pandemic response.

Patient Factors Impacting Baseline Motor Evoked Potentials (MEPs) in Patients Undergoing Cervical Spine Surgery for Myelopathy or Radiculopathy.

STUDY DESIGN: Retrospective review of 2532 adults who underwent elective surgery for cervical radiculopathy or myelopathy with intraoperative neuromonitoring (IONM) with motor evoked potentials (MEPs) between 2017 and 2019. OBJECTIVE: Evaluate attainability of monitorable MEPs across demographic, health history, and patient-reported outcomes measure (PROM) factors. SUMMARY OF BACKGROUND DATA: When baseline IONM responses cannot be obtained, the value of IONM on mitigating the risk of postoperative deficits is marginalized and a clinical decision to proceed must be made based, in part, on the differential diagnosis of the unmonitorable MEPs. Despite known associations with baseline MEPs and anesthetic regimen or preoperative motor strength, little is known regarding associations with other patient factors. METHODS: Demographics, health history, and PROM data were collected preoperatively. MEP baseline responses were reported as monitorable or unmonitorable at incision. Multivariable logistic regression estimated the odds of having at least one unmonitorable MEP from demographic and health history factors. RESULTS: Age [odds ratio (OR)=1.031, P <0.001], sex (male OR=1.572, P =0.007), a primary diagnosis of myelopathy (OR=1.493, P =0.021), peripheral vascular disease (OR=2.830, P =0.009), type II diabetes (OR=1.658, P =0.005), and hypertension (OR=1.406, P =0.040) were each associated with increased odds of unmonitorable MEPs from one or more muscles; a history of thyroid disorder was inversely related (OR=0.583, P =0.027). P atients with unmonitorable MEPs reported less neck-associated disability and pain ( P <0.036), but worse SF-12 physical health and lower extremity (LE) and upper extremity function ( P <0.016). Compared with radiculopathy, unmonitorable MEPs in myelopathy patients more often involved LE muscles. Cord function was monitorable in 99.1% of myelopathic patients with no reported LE dysfunction and no history of hypertension or diabetes. CONCLUSION: Myelopathy, hypertension, peripheral vascular disease, diabetes, and/or symptomatic LE dysfunction increased the odds of having unmonitorable baseline MEPs. Unmonitorable baseline MEPs was uncommon in patients without significant LE weakness, even in the presence of myelopathy.

Multi-institutional Analysis of 505 Patients With Coronavirus Disease-2019 Supported With Extracorporeal Membrane Oxygenation: Predictors of Survival.

BACKGROUND: We reviewed our experience with 505 patients with confirmed coronavirus disease-2019 (COVID-19) supported with extracorporeal membrane oxygenation (ECMO) at 45 hospitals and estimated risk factors for mortality. METHODS: A multi-institutional database was created and used to assess all patients with COVID-19 who were supported with ECMO. A Bayesian mixed-effects logistic regression model was estimated to assess the effect on survival of multiple potential risk factors for mortality, including age at cannulation for ECMO as well as days between diagnosis of COVID-19 and intubation and days between intubation and cannulation for ECMO. RESULTS: Median time on ECMO was 18 days (interquartile range, 10-29 days). All 505 patients separated from ECMO: 194 patients (38.4%) survived and 311 patients (61.6%) died. Survival with venovenous ECMO was 184 of 466 patients (39.5%), and survival with venoarterial ECMO was 8 of 30 patients (26.7%). Survivors had lower median age (44 vs 51 years, P < .001) and shorter median time interval from diagnosis to intubation (7 vs 11 days, P = .001). Adjusting for several confounding factors, we estimated that an ECMO patient intubated on day 14 after the diagnosis of COVID-19 vs day 4 had a relative odds of survival of 0.65 (95% credible interval, 0.44-0.96; posterior probability of negative effect, 98.5%). Age was also negatively associated with survival: relative to a 38-year-old patient, we estimated that a 57-year-old patient had a relative odds of survival of 0.43 (95% credible interval, 0.30-0.61; posterior probability of negative effect, >99.99%). CONCLUSIONS: ECMO facilitates salvage and survival of select critically ill patients with COVID-19. Survivors tend to be younger and have shorter time from diagnosis to intubation. Survival of patients supported with only venovenous ECMO was 39.5%.

The assessment of patients undergoing cardiac surgery for Covid-19: Complications occurring during cardiopulmonary bypass.

The outbreak of the novel coronavirus pandemic (COVID-19) has resulted in dramatic changes to the conduct of surgery both from a patient management perspective and in protecting healthcare providers. The current study reports on the status of COVID-19 infections in patients presenting for cardiac surgery with cardiopulmonary bypass (CPB) on circuit complications. A tracking process for monitoring the presence of COVID-19 in adult cardiac surgery patients was integrated into a case documentation system across United States hospitals where out-sourced perfusion services were provided. Assessment included infection status, testing technique employed, surgery status and CPB complications. Records from 5612 adult patients who underwent cardiac surgery between November 1, 2020 and January 18, 2021 from 176 hospitals were reviewed. A sub-cohort of coronary artery bypass graft patients (3283) was compared using a mixed effect binary logistic regression analysis. 4297 patients had negative test results (76.6%) while 49 (0.9%) tested positive for COVID-19, and unknown or no results were reported in 693 (12.4%) and 573 (10.2%) respectively. Coagulation complications were reported at 0.2% in the negative test results group versus 4.1% in the positive test result group (p < 0.001). Oxygenator gas exchange complications were 0.2% in the negative test results group versus 2.0% in the positive test results group (p = 0.088). Coronary artery bypass graft patients with a positive test had significantly higher risk for any CPB complication (p = 0.003) [OR 10.38, CI 2.18-49.53] then negative test patients [OR 0.01, CI 0.00-0.20]. The present study has shown that patients undergoing cardiac surgery with CPB who test positive for COVID-19 have higher CPB complication rate than those who test negative.

Peer selection and influence for marijuana use in a complete network of first-year college students.

BACKGROUND: Marijuana is the most frequently used illicit drug among college students, and there is a need to understand the social processes that contribute to young adults' marijuana use. Substance use behaviors tend to be more similar (homophilous) among individuals with social ties to one another. However, little is known about whether marijuana use homophily within young adult relationships is due to social selection (seeking out ties with similar marijuana use to one's own) or social influence (adopting similar marijuana use behaviors as one's ties), or both. METHODS: Students (N = 1,489; 54.6% female; Mage = 18.6 years) at one University completed online surveys in their first three semesters of college. Surveys assessed participant characteristics, marijuana use, and ties to up to 10 other students in the whole (sociocentric) network of first-year college students. Stochastic-actor oriented models (SAOMs) were used to analyze the co-evolution of marijuana use and social ties over time. RESULTS: Participants were more likely to select peers with similar past 30-day marijuana use as themselves. Concurrently, students' past 30-day marijuana use became more similar to their peers' use over time. DISCUSSION: Evidence for selection and influence effects were highly significant after controlling for network structure and other covariates indicating these processes may work in tandem to increase marijuana use homophily over the first year of college. This highlights the importance of relationships made early in the first-year of college, as these initial peer ties are likely to reinforce marijuana use behaviors that occur within these relationships.

Multi-institutional Analysis of 200 COVID-19 Patients Treated With Extracorporeal Membrane Oxygenation: Outcomes and Trends.

BACKGROUND: The role of extracorporeal membrane oxygenation (ECMO) in the management of patients with COVID-19 continues to evolve. The purpose of this analysis is to review our multi-institutional clinical experience involving 200 consecutive patients at 29 hospitals with confirmed COVID-19 supported with ECMO. METHODS: This analysis includes our first 200 COVID-19 patients with complete data who were supported with and separated from ECMO. These patients were cannulated between March 17 and December 1, 2020. Differences by mortality group were assessed using χ2 tests for categoric variables and Kruskal-Wallis rank sum tests and Welch's analysis of variance for continuous variables. RESULTS: Median ECMO time was 15 days (interquartile range, 9 to 28). All 200 patients have separated from ECMO: 90 patients (45%) survived and 110 patients (55%) died. Survival with venovenous ECMO was 87 of 188 patients (46.3%), whereas survival with venoarterial ECMO was 3 of 12 patients (25%). Of 90 survivors, 77 have been discharged from the hospital and 13 remain hospitalized at the ECMO-providing hospital. Survivors had lower median age (47 versus 56 years, P < .001) and shorter median time from diagnosis to ECMO cannulation (8 versus 12 days, P = .003). For the 90 survivors, adjunctive therapies on ECMO included intravenous steroids (64), remdesivir (49), convalescent plasma (43), anti-interleukin-6 receptor blockers (39), prostaglandin (33), and hydroxychloroquine (22). CONCLUSIONS: Extracorporeal membrane oxygenation facilitates survival of select critically ill patients with COVID-19. Survivors tend to be younger and have a shorter duration from diagnosis to cannulation. Substantial variation exists in drug treatment of COVID-19, but ECMO offers a reasonable rescue strategy.

Anticoagulant Use During Extracorporeal Membrane Oxygenation Using Heparin and Direct Thrombin Inhibitors in COVID-19 and ARDS Patients.

Coagulopathies develop in patients supported with the use of extracorporeal membrane oxygenation (ECMO) and can be hemorrhagic and/or thrombophilic in spite of the use of systemic anticoagulation. The purpose this study was to examine the use of heparin and direct thrombin inhibitors (DTI) in COVID-19 patients with acute respiratory distress syndrome (ARDS) on ECMO, with a subset analysis by disease state. Following IRB approval, 570 consecutive records were reviewed of adult patients on venovenous ECMO between May 2020 and December 2021. Patients were grouped by anticoagulant use: Heparin Only (n = 373), DTI Only (bivalirudin or argatroban, n = 90), or DTI after Heparin (n = 107). The effect of anticoagulant grouping was assessed using Bayesian mixed-effects logistic regression adjusting for age, body mass index (BMI), gender, days of mechanical ventilation prior to ECMO, indication for ECMO support, hepatic and renal failure, hours on ECMO, hours off anticoagulation, coagulation monitoring target, and hospital. The primary endpoint was circuit failure requiring change-out with secondary endpoints of organ failure and mortality. Regression-adjusted probability of circuit change-outs were as follows: DTI after Heparin patients-32.7%, 95% Credible Interval [16.1-51.9%]; DTI Only patients-23.3% [7.5-40.8%]; and Heparin Only patients-19.8% [8.1-31.3%]. The posterior probability of difference between groups was strongest for DTI after Heparin vs. Heparin Only (97.0%), moderate for DTI after Heparin vs. DTI Only (88.2%), and weak for DTI Only vs. Heparin only (66.6%). The occurrence of both hepatic and renal failure for DTI Only and DTI after Heparin patients was higher than that of Heparin Only patients. Unadjusted mortality was highest for DTI after Heparin (64.5%) followed by DTI Only (56.7%), and Heparin Only (50.1%, p = 0.027). DTI after Heparin was associated with an increased likelihood of circuit change-out. Unadjusted hepatic failure, renal failure, and mortality were more frequent among DTI patients than Heparin Only patients.

Impact of inhalational anesthetic agents on the baseline monitorability of motor evoked potentials during spine surgery: a review of 22,755 cervical and lumbar procedures.

BACKGROUND CONTEXT: During spine surgery, motor evoked potentials (MEPs) are often utilized to monitor both spinal cord function and spinal nerve root or plexus function. While there are reports evaluating the impact of anesthesia on the ability of MEPs to monitor spinal cord function, less is known about the impact of anesthesia on the ability of MEPs to monitor spinal nerve root and plexus function. PURPOSE: To compare the baseline monitorability and amplitude of MEPs during cervical and lumbar procedures between two cohorts based on the maintenance anesthetic regimen: a total intravenous anesthesia (TIVA) versus a regimen balanced with volatile inhalational and intravenous agents. STUDY DESIGN: Baseline MEP data from a total of 16,559 cervical and 6,196 lumbar extradural spine procedures utilizing multimodality intraoperative neuromonitoring (IONM) including MEPs between January 2017 and March 2020 were obtained from a multi-institutional database. Two cohorts for each region of spine surgery were delineated based on the anesthetic regimen: a TIVA cohort and a Balanced anesthesia cohort. PATIENT SAMPLE: Age 18 and older. Fellowship support for 65,000 for year 2021. OUTCOME MEASURES: Percent monitorability and amplitudes of baseline MEPs. METHODS: The baseline monitorability of each muscle MEP was evaluated by the IONM team in real-time and recorded in the patient's electronic medical record. The relation between anesthetic regimen and baseline monitorability was estimated using mixed effects logistic regression, with distinct models for cervical and lumbar procedures. Subsets of cervical and lumbar procedures from each anesthesia cohort in which all MEPs were deemed monitorable were randomly selected and the average peak-to-trough amplitude of each muscle MEP was retrospectively measured. Mixed-effects linear regression models were estimated (one each for cervical and lumbar procedures) to assess possible differences in average amplitude associated with anesthesia regimen. RESULTS: At the time of surgery, baseline MEPs were reported monitorable from all targeted muscles in 86.8% and 83.0% of cervical and lumbar procedures, respectively, for the TIVA cohort, but were reported monitorable in just 59.3% and 61.0% of cervical and lumbar procedures, respectively, in the Balanced cohort, yielding disparities of 27.5% and 22.0%, respectively. The model-adjusted monitorability disparity between cohorts for a given muscle MEP ranged from 0.2% to 16.6% but was smallest for distal intrinsic hand and foot muscle MEPs (0.2%-1.1%) and was largest for proximal muscle MEPs (deltoid: 10.8%, biceps brachii: 8.8%, triceps: 13.0%, quadriceps: 16.6%, gastrocnemius: 7.8%, and tibialis anterior: 3.7%) where the monitorability was significantly decreased in the Balanced cohort relative to the TIVA cohort (p<.0001). Relative to the TIVA cohort, the model-adjusted amplitude of an MEP in the Balanced cohort was smaller for all muscles measured, ranging from 27.5% to 78.0% smaller. Relative to the TIVA cohort, the model-adjusted amplitude of an MEP was significantly decreased (p<.01) in the Balanced cohort for the most proximal muscles (Percent smaller: deltoid: 74.3%, biceps: 78.0%, triceps: 54.9%, quadriceps: 54.8%). CONCLUSIONS: TIVA is the preferred anesthetic regimen for optimizing MEP monitoring during spine surgery. Inhalational agents significantly decrease MEP monitorability and amplitudes for most muscles, and this effect is especially pronounced for proximal limb muscles such as the deltoid, biceps, triceps, and quadriceps.

Zero-Balance Ultrafiltration during Cardiopulmonary Bypass Is Associated with Decreased Urine Output.

Zero-balance ultrafiltration (ZBUF) during cardiopulmonary bypass (CPB) has been purported to reduce pro-inflammatory mediators during cardiac surgery. However, its clinical benefit is equivocal and its effect on renal function unknown. The purpose of this study was to examine the effect of ZBUF on urine output in adult patients undergoing CPB. Following institutional review board approval, 98,953 records from a national registry of adult patients at 215 U.S. hospitals between January 2016 and September 2019 were reviewed. Groups were stratified according to ZBUF use. Anuric patients were excluded from the study as they were patients with missing data on urine output, ultrafiltration use, or ZBUF volume. The primary endpoint was intraoperative urine output normalized to body weight and procedure duration (total operative time). Final analysis of this endpoint was carried out using a linear mixed-effects regression model adjusting for patient and procedural characteristics, as well as practice patterns associated with surgeons and perfusionists. There was a significant 16.1% reduction in median urine output for ZBUF patients (.94 [.54, 1.47] mL/kg/h) vs. the non-ZBUF group (1.12 [.70,-1.73] mL/kg/h), p < .001. After statistically adjusting for patient and procedural characteristics, each liter of ZBUF volume was associated with an estimated change in intraoperative urine output of -.03 mL/kg/h (95% CI: [-.04 to -.02], p < .001). The median ZBUF volume was 1,550 [1,000, 2,600] mL, and when ZBUF was used, conventional ultrafiltration (CUF) was more likely to be used as well (88.4% vs. 44.8%, p < .001). ZBUF patients had median asanguineous volume and crystalloid cardioplegia nearly two times more than non-ZBUF patients, and had slightly higher red blood cell transfusions (17.6% vs. 16.3%, p < .05). The application of ZBUF during CPB was associated with patients having lower urine output and significantly higher use of CUF. Further research is required to determine if these results are reproducible in prospective clinical studies.

Multi-institutional Analysis of 100 Consecutive Patients with COVID-19 and Severe Pulmonary Compromise Treated with Extracorporeal Membrane Oxygenation: Outcomes and Trends Over Time.

The role of extracorporeal membrane oxygenation (ECMO) in the management of severely ill patients with coronavirus disease 2019 (COVID-19) continues to evolve. The purpose of this study is to review a multi-institutional clinical experience in 100 consecutive patients, at 20 hospitals, with confirmed COVID-19 supported with ECMO. This analysis includes our first 100 patients with complete data who had confirmed COVID-19 and were supported with ECMO. The first patient in the cohort was placed on ECMO on March 17, 2020. Differences by the mortality group were assessed using χ2 tests for categorical variables and Kruskal-Wallis rank-sum tests and Welch's analysis of variance for continuous variables. The median time on ECMO was 12.0 days (IQR = 8-22 days). All 100 patients have since been separated from ECMO: 50 patients survived and 50 patients died. The rate of survival with veno-venous ECMO was 49 of 96 patients (51%), whereas that with veno-arterial ECMO was 1 of 4 patients (25%). Of 50 survivors, 49 have been discharged from the hospital and 1 remains hospitalized at the ECMO-providing hospital. Survivors were generally younger, with a lower median age (47 versus 56.5 years, p = 0.014). In the 50 surviving patients, adjunctive therapies while on ECMO included intravenous steroids (26), anti-interleukin-6 receptor blockers (26), convalescent plasma (22), remdesivir (21), hydroxychloroquine (20), and prostaglandin (15). Extracorporeal membrane oxygenation may facilitate salvage and survival of selected critically ill patients with COVID-19. Survivors tend to be younger. Substantial variation exists in the drug treatment of COVID-19, but ECMO offers a reasonable rescue strategy.

Application of goal-directed therapy for the use of concentrated antithrombin for heparin resistance during cardiac surgery.

The maintenance of anticoagulation in adult patients undergoing cardiopulmonary bypass is dependent upon a number of factors, including heparin concentration and adequate antithrombin activity. Inadequate anticoagulation increases the risk of thrombosis and jeopardizes both vascular and extracorporeal circuit integrity. The purpose of this study was to evaluate a goal-directed approach for the use of antithrombin in patients who were resistant to heparin. Following institutional review board approval, data were obtained from quality improvement records. A goal-directed protocol for antithrombin was established based upon heparin dosing (400 IU kg-1 body weight) and achieving an activated clotting time of ⩾500 seconds prior to cardiopulmonary bypass. Two groups of patients were identified as those receiving antithrombin and those not receiving antithrombin. Outcome measures included activated clotting time values and transfusion rates. Consecutive patients (n = 140) were included in the study with 10 (7.1%) in the antithrombin group. The average antithrombin dose was 1,029.0 ± 164.5 IU and all patients had restoration to the activated clotting time levels. Patients in the antithrombin group were on preoperative heparin therapy (80.0% vs. 24.6%, p = 0.001). Prior to cardiopulmonary bypass the activated clotting time values were lower in the antithrombin group (417.7 ± 56.1 seconds vs. 581.1 ± 169.8 seconds, p = 0.003). Antithrombin patients had a lower heparin sensitivity index (0.55 ± 0.17 vs. 1.05 ± 0.44 seconds heparin-1 IU kg-1, p = 0.001), received more total heparin (961.3 ± 158.5 IU kg-1 vs. 677.5 ± 199.0 IU kg-1, p = 0.001), more cardiopulmonary bypass heparin (22,500 ± 10,300 IU vs. 12,100 ± 13,200 IU, p = 0.016), and more protamine (5.4 ± 1.2 vs. 4.1 ± 1.1 mg kg-1, p = 0.003). The intraoperative transfusion rate was higher in the antithrombin group (70.0% vs. 35.4%, p = 0.035), but no differences were seen postoperatively. Utilization of a goal-directed algorithm for the administration of antithrombin for the treatment of heparin resistance is effective in patients undergoing cardiac surgery.

The Use of Extracorporeal Membrane Oxygenation in COVID-19 Patients with Severe Cardiorespiratory Failure: The Influence of Obesity on Outcomes.

Extracorporeal membrane oxygenation (ECMO) in the management of severely ill patients with COVID-19 has been reported in more than 5,827 cases worldwide according to the Extracorporeal Life Support Organization (ELSO). Several pre-existing conditions have been linked to an increase in COVID-19 mortality risk including obesity. The purpose of this research is to review the clinical experience from a cohort of 342 COVID-19 patients treated with ECMO in which 61.7% (211/342) are confirmed obese. Following institutional review board approval, we reviewed all 342 COVID-19 patients supported with ECMO between March 17, 2020 and March 18, 2021, at 40 American institutions from a multi-institutional database. Descriptive statistics comparing survivors to non-survivors were calculated using chi-square, Welch's ANOVA, and Kruskal-Wallis rank sum test as appropriate. Multivariable logistic regression was used to estimate the effect of body mass index (BMI) on the odds of survival while adjusting for age, gender, chronic renal failure, diabetes, asthma, hypertension, and pre-ECMO P/F ratio. Descriptive analysis showed that obese patients were more likely to be hypertensive (58.1% vs. 32%, p < .001), diabetic (42% vs. 30%, p < .05), and female (35% vs. 21%, p < .05), and had longer median days from intubation to cannulation (4.0 vs. 2.0, p < .05). Obese patients appeared to also have a slightly lower median age (47.9 vs. 50.5, p = .07), higher incidence of asthma (17.8% vs. 10.2%, p = .09), and a slightly lower pre-ECMO PaO2/FiO2 ratio (67.5 vs. 77.5, p = .08) though these differences were slightly less statistically reliable. Results from the logistic regression model suggest no statistically reliable association between BMI and odds of survival. Age had a moderately large and statistically reliable negative association with survival; the relative odds of survival for a 59-year-old patient were approximately half those of a 41-year-old patient (OR = .53, 95% CI: .36-.77, p < .001). Obesity does not seem to be a major risk factor for poor outcomes in COVID-19 patients supported with ECMO; however, age was moderately negatively associated with survival. The potential influence of other comorbidities on odds of survival among these patients warrant further investigation.

The Effect of Antifibrinolytic Use on Intraoperative Cell Salvage: Results from a National Registry of Surgical Procedures.

Intraoperative cell salvage (ICS) is a critical component of any blood management program involving surgery with a high potential for blood loss. The introduction of antifibrinolytics (AF) may reduce blood loss. The purpose of this study was to evaluate the use of AF on ICS in non-cardiac surgical procedures. Following institutional review board approval, 69,935 consecutive case records between January 2016 and September 2019 from a national registry of adult surgical patients were reviewed. Procedure types were stratified into one of nine surgical categories: general (GN, n = 1,525), neurosurgical (NS, n = 479), obstetric (OB, n = 1,563), cervical spine (CS, n = 2,701), lumbar spine (LS, n = 38,383), hip arthroplasty (HA, n = 13,327), knee arthroplasty (KA, n = 596), vascular (VA, n = 9,845), or orthopedic other (OO, n = 1,516). The primary endpoint was the use of AF with the secondary endpoints ICS shed blood volume and volume available for return. The overall use of AF across all surgical procedures increased from 21.4% in 2016 to 25.4% in 2019. The greatest increases were seen in NS (4.4% to 16.2%), LS (13.7% to 23.1%), and HA (55.8% to 61.9%). For several procedure types, there was an initial increase then either a leveling off or a decline in AF use: OB initially increased from 6.2% to 10.8% in 2018, whereas GN (9.4% to 7.2%) and VA surgery declined slightly (9.9% to 5.7%). When comparing patients who did not receive AF with those who did, there were similar volumes of ICS available for return in all groups, except for LS, GN, and VA, where lower volumes were seen in the No-AF groups. The use of AF has increased each year over the 4-year period in most of the surgical categories, but several have declined. There may be a beneficial effect of AF with lower ICS volumes available for return in a few groups.

Extracorporeal Membrane Oxygenation in the Treatment of Severe Pulmonary and Cardiac Compromise in Coronavirus Disease 2019: Experience with 32 Patients.

As coronavirus disease 2019 (COVID-19) cases surge worldwide, an urgent need exists to enhance our understanding of the role of extracorporeal membrane oxygenation (ECMO) in the management of severely ill patients with COVID-19 who develop acute respiratory and cardiac compromise refractory to conventional therapy. The purpose of this manuscript is to review our initial clinical experience in 32 patients with confirmed COVID-19 treated with ECMO. A multi-institutional registry and database was created and utilized to assess all patients who were supported with ECMO provided by SpecialtyCare. Data captured included patient characteristics, pre-COVID-19 risk factors and comorbidities, confirmation of COVID-19 diagnosis, features of ECMO support, specific medications utilized to treat COVID-19, and short-term outcomes through hospital discharge. This analysis includes all of our patients with COVID-19 supported with ECMO, with an analytic window starting March 17, 2020, when our first COVID-19 patient was placed on ECMO, and ending April 9, 2020. During the 24 days of this study, 32 consecutive patients with COVID-19 were placed on ECMO at nine different hospitals. As of the time of analysis, 17 remain on ECMO, 10 died before or shortly after decannulation, and five are alive and extubated after removal from ECMO, with one of these five discharged from the hospital. Adjunctive medication in the surviving patients while on ECMO was as follows: four of five survivors received intravenous steroids, three of five survivors received antiviral medications (Remdesivir), two of five survivors were treated with anti-interleukin-6-receptor monoclonal antibodies (Tocilizumab or Sarilumab), and one of five survivors received hydroxychloroquine. Analysis of these 32 COVID-19 patients with severe pulmonary compromise supported with ECMO suggests that ECMO may play a useful role in salvaging select critically ill patients with COVID-19. Additional patient experience and associated clinical and laboratory data must be obtained to further define the optimal role of ECMO in patients with COVID-19 and acute respiratory distress syndrome (ARDS). These initial data may provide useful information to help define the best strategies to care for these challenging patients and may also provide a framework for much-needed future research about the use of ECMO to treat patients with COVID-19.

Therapeutic Impact of Traction Release After C5 Nerve Root Motor Evoked Potential (MEP) Alerts in Cervical Spine Surgery.

STUDY DESIGN: A retrospective review of 40,919 cervical spine surgeries monitored with motor evoked potentials (MEPs) from a multi-institutional intraoperative neuromonitoring database. OBJECTIVE: The objective of this study was to determine the clinical impact of interventions prompted by C5 spinal nerve root MEP alerts. SUMMARY OF BACKGROUND DATA: MEPs have been shown to diagnose acute C5 palsies, but additional data are needed regarding the clinical impact of interventions in response to C5 MEP alerts. MATERIALS AND METHODS: Procedures with isolated C5 MEP alerts were categorized as fully resolved, partially resolved, or unresolved based on the status of signals at closure. Clinical outcomes were based on neurological assessment in the immediate postoperative period. The sensitivity, specificity, likelihood ratios, and odds ratios (ORs) of C5 MEP alerts for acute C5 palsies were calculated. RESULTS: The odds of an acute C5 palsy greatly increased if there was a C5 MEP alert [OR=340.9; 95% confidence (CI): 173.0, 671.6; P<0.0001], and increased further if the alert persisted through closure (OR=820.8; 95% CI: 398.1, 1692.0; P<0.0001). Relative to procedures with unresolved C5 MEP alerts, the risk of an acute C5 palsy significantly decreased if a C5 MEP alert was fully resolved by closure (OR=0.07; 95% CI: 0.02, 0.25; P<0.0001). For alerts resolved during positioning or exposure, 90.9% were resolved with the release of positional traction, and for resolved alerts that occurred after exposure, 36.3% involved just traction release, 14.1% involved both traction release and surgical action, and 30.3% involved just surgical action. The sensitivity of C5 MEP alerts for acute C5 palsies was anesthetic dependent: 89.7% (26/29) in the total intravenous regimen cohort but just 50.0% (10/20) in the inhalational anesthesia cohort. CONCLUSIONS: The timely release of positional traction is an effective intervention for resolving C5 MEP alerts and reducing the odds of an acute postoperative C5 palsy. Surgical maneuvers, such as the release of distraction or graft adjustment, should be attempted in conjunction with traction release depending on the surgical context of the alert. LEVEL OF EVIDENCE: Level IV.

The effect of various blood management strategies on intraoperative red blood cell transfusion in first-time coronary artery bypass graft patients.

Effective blood management during cardiac surgery requires a multifactorial effort to limit exposure to allogeneic blood products. The present study evaluated the distribution of intraoperative interventions in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Records from patients undergoing non-reoperative surgery at 120 hospitals between January 2017 and December 2017 were reviewed, and red blood cell transfusion quartiles established. The 31 hospitals with the lowest transfusion rates fell into the first quartile (low transfusion group, n = 3,186 patients), while 29 hospitals with the highest transfusion were in the fourth quartile (high transfusion group, n = 2,561). A survey was sent to assess the blood management techniques: acute normovolemic hemodilution, autologous prime, fluid management, intraoperative autotransfusion, ultrafiltration, and transfusion triggers. All data are presented as mean (standard deviation). Patients in the low transfusion group had red blood cell transfusion rate of 5.5%, while the high transfusion group was 28.3%. There was no difference in gender or age. Fluid management was reduced in the low transfusion group with smaller prime volumes and anesthesia volumes, but higher crystalloid use during cardiopulmonary bypass. The low transfusion group did not use acute normovolemic hemodilution as often and had lower sequestered volumes when used. When ultrafiltration was used, the low transfusion quartile group removed more volume (1,555.9 ± 955.2 vs. 1,326.1 ± 918.9 mL, p ⩽ 0.001). In the low transfusion group, nadir hematocrit on-cardiopulmonary bypass averaged 1.6% lower and 3.0% lower for transfusion post-cardiopulmonary bypass. Intraoperative red blood cell units averaged 0.11 ± 0.50 U in low transfusion group compared to 0.63 ± 1.14 U in the high transfusion group. Mixed-effects logistic regression identified first in operating room and first on cardiopulmonary bypass hematocrit, estimated blood volume and nadir hematocrit transfusion trigger as the strongest predictors for red blood cell transfusion. Significant variation exists in the transfusion of red blood cell in coronary artery bypass graft patients undergoing cardiopulmonary bypass which may be related to the application of intraoperative blood management techniques.