Atmospheric Carbon and Transport - America (ACT-America) Data Sets: Description, Management, and Delivery.

The ACT-America project is a NASA Earth Venture Suborbital-2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT-America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower-based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016-2019 over three regions of the US (Mid-Atlantic, Midwest and South) using two NASA research aircraft (B-200 and C-130). We performed three flight patterns (fair weather, frontal crossings, and OCO-2 underflights) and collected more than 1,140 h of airborne measurements via level-leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT-America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT-America data sets.

Predictive factors for the development of surgical site infection in adults undergoing initial open inguinal hernia repair.

INTRODUCTION: Despite being one of the most commonly performed general surgery procedures, surgical site infection (SSI) is still seen in primary, elective, open inguinal hernia repair. Studies have reported a wide range of infection rates, yet predictive risk factors have not been definitely identified leading to variability and controversy in the use of pre-operative antibiotics. In this study, the authors seek to identify factors predictive of SSI development in a large cohort of patients undergoing initial unilateral open inguinal repair. METHODS: The American College of Surgery National Surgical Quality Improvement Program (ACS NSQIP) personal use file (PUF) database was queried for initial, open, reducible inguinal hernia repair cases in adults with clean surgical sites performed from 2012 to 2015 (CPT 49,505 and class one wound). Patient data were analyzed using univariate and multivariate analysis to identify factors predictive of surgical site infection. RESULTS: 57,951 cases were identified. 90.8% were men with an average age of 58.2 years and a median operative time of 53.0 min. Of all variables evaluated with univariate logistic regression, 17 demonstrated an association with surgical site infection. Performing multiple logistic regression on those 17 variables yielded 3 factors independently associated with surgical site infection: diabetes (OR 2.017, 95% CI 1.012-4.023), BMI ≥ 35 kg/m2 (OR 2.587, 95% CI 1.123-5.964), and current smoking (OR 2.071, 95% CI 1.126-3.811). CONCLUSION: Diabetes, BMI ≥ 35 kg/m2, and current smoking are significantly associated with an increased odds surgical site infection after initial, open, reducible inguinal hernia repair in adults with clean surgical sites.

Effect of hematocrit on regional oxygen delivery and extraction in an adult respiratory distress syndrome animal model.

BACKGROUND: The purpose of this prospective, randomized, controlled study was to investigate the effects of hematocrit (Hct) on regional oxygen delivery and extraction following induction of adult respiratory distress syndrome (ARDS) in an animal model. METHODS: Animals were instrumented to monitor central venous pressure (CVP), systemic mean arterial pressure (MAP), pulmonary artery occlusion pressure (PAOP), and cardiac output (CO) and to measure blood flow in the renal, hepatic, and superior mesenteric arteries and portal vein. ARDS was induced, positive end expiratory pressure (PEEP) applied and CO was maximized with volume loading and epinephrine infusion. Data were acquired at baseline (BL) and at Hct levels ranging from 25% to 50%. RESULTS: Systemic DO(2) increased steadily and significantly with increased Hct. Systemic O(2) extraction ratio (O(2)ER) decreased significantly with increasing Hct until a threshold value of 40%, after which further increases in Hct did not cause a statistically significant decrease in O(2)ER. Similarly, renal and hepatic DO(2) increased and O(2)ER decreased in a statistical significant manner with transfusions up to a Hct of 35%. In the splanchnic circulation blood transfusions did not cause any statistically significant increase in DO(2), and O(2)ER showed no decrease after an Hct of 35%. Systemic, renal, hepatic, and splanchnic VO(2) were not affected by changes in Hct. Blood viscosity decreased from a baseline value of 2.9+/-0.2 centipoise at a Hct of 38% to 2.3+/-0.1 centipoise at a Hct of 25% (P<0.05). Viscosity increased progressively with increasing hematocrits and reached the value of 4.2+/-0.2 centipoise at an Hct of 50% (P<0.05 versus Hct 30%, 35%, 40%, 45%). CONCLUSIONS: Based on the results of this non-supply-dependent animal model we conclude that a progressive increase in Hct up to 40% causes a corresponding increase in systemic DO(2) associated with a decrease in O(2)ER. However, there is no improvement in renal, hepatic, and splanchnic DO(2) and O(2)ER after a threshold Hct of 35%. All other factors being the same, an Hct greater than 35% may in fact cause a decrease in blood flow rate and change in blood flow characteristics as a consequence of increased blood kinematic viscosity, which may alter and compromise cellular oxygen transfer.

Prolonged lactate clearance is associated with increased mortality in the surgical intensive care unit.

BACKGROUND: Failure of arterial serum lactate to achieve normal levels has been associated with an increased mortality among medical and trauma patients. At our institution the ability of the patient to normalize arterial serum lactate has been utilized as an end point of resuscitation. In this study, we examine the correlation between length of time to lactate normalization and mortality. METHODS: The charts of 95 consecutive surgical intensive care unit (SICU) patients requiring hemodynamic monitoring or therapy were reviewed retrospectively. Hemodynamic, demographic, and laboratory data were recorded. Patients were stratified by lactate normalization time, and a subgroup analysis of survivors and nonsurvivors was performed by univariate and multivariate analysis. RESULTS: Patients not achieving a normal lactate level sustained a 100% hospital mortality rate. Those clearing between 48 and 96 hours sustained a 42.5% mortality rate. Patients normalizing in 24 to 48 hours had a 13.3% mortality rate, and those clearing in less than 24 hours had a mortality rate of 3.9%. Subgroup analysis by survival revealed differences in time to lactate clearance, initial blood pressure, and initial lactate on univariate analysis. On multivariate analysis only time of lactate clearance was found to differ. CONCLUSIONS: Prolongation of lactate clearance is associated with increasing mortality. Failure of a patient to normalize lactate is associated with 100% mortality. Measurement of arterial serum lactate is a simple and effective predictor of outcome and end point of therapy.

Acute necrotizing torsion of the gallbladder.

Torsion of the gallbladder is an extremely rare cause of acute surgical abdomen. Although gallbladder torsion has been reported the diagnosis remains elusive and is often missed. A case of necrotizing gallbladder torsion is examined, and the literature is reviewed by the authors. History peak incidence and pathophysiology are discussed, and possible risk factors are identified. We conclude that torsion of the gallbladder is a condition that has minimal clinical findings.

A comparison of predictive outcomes of APACHE II and SAPS II in a surgical intensive care unit.

The Acute Physiologic Score and Chronic Health Evaluation (APACHE) II and the Simplified Acute Physiologic Scale (SAPS) II are two of the more commonly employed predictors of outcome and performance in the intensive care unit setting. However, controversy persists about whether the scores generated by these systems have similar predictive value. This study compared the predicted mortalities derived from APACHE II and SAPS II and contrasted them to the actual mortality in a surgical intensive care unit (SICU). Data for 1665 patients admitted to the SICU between July 1994 and August 1997 were entered into an SICU computerized database. From recorded demographic, hemodynamic, and laboratory data, APACHE II and SAPS II scores were obtained with corresponding predicted mortalities. Patients were stratified by age into categories of less than and greater than 65 years old. Predicted mortalities by APACHE II and SAPS II were compared for each group. An additional analysis included a comparison of survivors and nonsurvivors. There was no significant difference in predicted mortality between APACHE II and SAPS II in any of the groups. Actual mortality was 30 of 486 (6.2%) in patients less than 65 years of age and 73 of 1179 (6.2%) in patients 65 years of age or greater. The APACHE II and SAPS II predicted mortalities (mean +/- SD) for patients less than 65 years of age were 10.5% +/- 10.6% and 10.9% +/- 13.3%, respectively (P > .05). The APACHE II and SAPS II predicted mortalities in patients 65 years of age or greater were 19.1% +/- 17.8% and 18.7% +/- 21.0%, respectively (P > .05). Similarly, when patients were stratified by survival status, no significant difference was present between groups. However, in individual patients, a difference between APACHE II and SAPS II scores was often present. We conclude that although disparities between APACHE II and SAPS II predicted mortalities in individual patients may be significant, APACHE II and SAPS II have similar predictive value in a large SICU patient population. However, both APACHE II and SAPS II systems overestimate mortality in SICU patients. Based on our results, we conclude that either system can be used to measure quality of care in the SICU; however, neither system can be reliably applied to a single patient.