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.

Takotsubo cardiomyopathy: an uncommon cause of ST segment elevation in intensive care

A 63-year-old female developed respiratory failure and was admitted to the Intensive Care Unit for non-invasive ventilation, inotropic support and antibiotic therapy. The patient was initially stable but then suddenly deteriorated with acute pulmonary oedema requiring mechanical ventilation. An electrocardiogram showed an acute ST elevation myocardial infarction and the patient subsequently had an urgent coronary angiogram which revealed normal coronary arteries but apical ballooning characteristic of Takotsubo cardiomyopathy. A short review is provided of this relatively newly described heart syndrome which has the potential to present in numbers of intensive care patients. This case emphasises the importance of being aware of uncommon causes of acute ECG changes in the critically ill.

Does washing swabs increase the efficiency of red cell recovery by cell salvage in aortic surgery?

BACKGROUND AND OBJECTIVES

We investigated the contribution of swab washing to the efficiency of red cell recovery by intraoperative cell salvage (ICS) in 10 patients undergoing elective aortic aneurysm repair.

MATERIALS AND METHODS

Volumes and haemoglobin (Hb) concentrations were recorded in the blood recovered by direct suction and from washed swabs, both before and after processing with a Haemonetics Cell Saver 5.

RESULTS

The mean +/- standard deviation (SD) estimated blood loss was 991 +/- 403 ml, resulting in a mean +/- SD salvaged RBC volume of 380 +/- 124 ml. The median [interquartile (IQR) range] Hb collected from suction was 84.9 (61.8-131.4) g, of which 50.1 (45-71.5) g was returned to the patient after processing, a median yield of 68 (49-77)%. The swab wash produced a median (IQR) Hb of 39.4 (28.4-64.9) g, of which 26.2 (16.8-31) g was reinfused, a 67 (33-98)% yield. Swab wash thus contributed with a median (IQR) of 31 (24-39)% of the total RBC recovery.

CONCLUSIONS

Washing swabs improves the efficiency of red cell recovery by ICS.

Respiratory muscle activity during REM sleep in patients with diaphragm paralysis

The diaphragm is the main inspiratory muscle during REM sleep. It was hypothesized that patients with isolated bilateral diaphragm paralysis (BDP) might not be able to sustain REM sleep. Polysomnography with EMG recordings was undertaken from accessory respiratory muscles in patients with BDP and normal subjects. Patients with BDP had a normal quantity of REM sleep (mean +/- SD, 18.6 +/- 7.5% of total sleep time) achieved by inspiratory recruitment of extradiaphragmatic muscles in both tonic and phasic REM, suggesting brainstem reorganization.

A preliminary study on adaptive field-of-view tracking in peripheral digital subtraction angiography

About two million peripheral angiographies are performed annually in the United States, hence a reduction in exposure would yield significant healthcare benefits. The synchronization of bolus traveling, the table motion, and the fluoroscopic imaging chain can be highly effective for dose reduction in Digital Subtraction Angiography (DSA) by minimizing the field-of-view according to the vascular anatomy of the region traveled by the bolus. The goal of this paper is to demonstrate the feasibility of adjusting the field-of-view while tracking the contrast bolus, thus reducing the dosage of both the bolus and the radiation. The speed of the bolus is respectively estimated in the systole and diastole stages. An EKG-gated Hammerstein model is used to predict the bolus chasing speed. A real-time algorithm is designed to extract the bolus dynamics, and define the field of view transversely and longitudinally. A limb stabilization technique is also presented to suppress any significant image misalignment. Our simulation results show that the proposed techniques are promising for clinical applications.

Endoscopic assessment of oesophagitis: clinical and functional correlates and further validation of the Los Angeles classification

BACKGROUND

Endoscopic oesophageal changes are diagnostically helpful and identify patients exposed to the risk of disease chronicity. However, there is a serious lack of agreement about how to describe and classify the appearance of reflux oesophagitis

AIMS

To examine the reliability of criteria that describe the circumferential extent of mucosal breaks and to evaluate the functional and clinical correlates of patients with reflux disease whose oesophagitis was graded according to the Los Angeles system.

METHODS

Forty six endoscopists from different countries used a detailed worksheet to evaluate endoscopic video recordings from 22 patients with the full range of severity of reflux oesophagitis. In separate studies, Los Angeles system gradings were correlated with 24 hour oesophageal pH monitoring (178 patients), and with clinical trials of omeprazole treatment (277 patients).

RESULTS

Evaluation of circumferential extent of oesophagitis by the criterion of whether mucosal breaks extended between the tops of mucosal folds, gave acceptable agreement (mean kappa value 0.4) among observers. This approach is used in the Los Angeles system. An alternative approach of grouping the circumferential extent of mucosal breaks as occupying 0-25%, 26-50%, 51-75%, 76-99%, or 100% of the oesophageal circumference, gave unacceptably high interobserver variation (mean kappa values 0-0.15) for all but the lowest category of extent (mean kappa value 0.4). Severity of oesophageal acid exposure was significantly (p<0.001) related to the severity grade of oesophagitis. Preteatment oesophagitis grades A-C were related to heartburn severity (p<0.01), outcomes of omeprazole (10 mg daily) treatment (p<0.01), and the risk for symptom relapse off therapy over six months (p<0.05).

CONCLUSIONS

Results add further support to previous studies for the clinical utility of the Los Angeles system for endoscopic grading of oesophagitis.

Association of adult achalasia and alacrima

Achalasia is the best described motor disorder of the esophagus. Associations with familial glucocorticoid deficiency and alacrima (triple A syndrome) have been described in the pediatric population, but no attention has been paid to the possibility of this association in adults. Tear production was assessed in 20 patients with achalasia and 20 age- and sex-matched controls. Deficient tears were found in four achalasics compared with none among the controls (P < 0.05). This suggests that some variant of the triple A Syndrome (achalasia, alacrima, and adrenocortical insufficiency) may exist in adult patients with achalasia as well.

A look back at the year in health law

The Bennett article takes us back to 1997 and reviews key legislators, regulations and judicial developments in Medicare, antitrust, tax and ERISA, all of which greatly impact the practice of health law.

Consultants' study leave--value for money?

The consultants in a single large acute hospital trust were given a personal allocation of 500.00 pounds for study leave and asked to supply reports on the purpose and value of that leave. The majority of consultants (82%) took leave during the 12-month period at an average cost of 182.80 pounds for each episode. Most was regarded of value and the majority was shared with other members of staff.

The endoscopic assessment of esophagitis: a progress report on observer agreement

BACKGROUND & AIMS

The study and management of reflux esophagitis require an endoscopic classification system founded on esophageal lesions that can be reproducibly identified. The aim of this study was to investigate interobserver agreement for the identification of endoscopic lesions typical of reflux esophagitis.

METHODS

Paired comparisons of observers' descriptions were obtained. Seventeen endoscopists assessed 100 still images, and 42 endoscopists, including 13 endoscopists in training, assessed 23 endoscopic video recordings. In a third, ancillary study, using a simpler evaluation sheet, 219 gastroenterologists recorded their assessments of 20 still images.

RESULTS

The agreement between endoscopists was similar for still images and video recordings. Agreement between experienced endoscopists was acceptable to good for recognition of minimal changes (erythema, friability, mucosal edema; kappa = 0.46 to kappa = 0.8), mucosal breaks (discretely, demarcated areas of slough or erythema; kappa = 0.84), and complications (ulceration, kappa = 0.92; stricturing, kappa = 0.80; columnar metaplasia, kappa = 0.81), although there was poor agreement when the circumferential extent and number of mucosal breaks were assessed. However, total circumferential extent of the mucosal break had a kappa value of 0.59. Agreement between inexperienced endoscopists was poor for recognition of minimal changes but was good for recognition of complications (kappa, 0.70-0.90).

CONCLUSIONS

Endoscopists can identify mucosal breaks confined to a mucosal fold and lesions that extend throughout the esophageal circumference. Complications of reflux disease can be reproducibly recorded. Criteria for assessing the number of mucosal breaks and their radial extent must be defined more clearly, as must the features of minimal change esophagitis.

Coeliac disease and bone mineral density in adult female patients

A cross sectional study was undertaken to examine the relationship between coeliac disease and bone mineral density. The 135 female coeliac patients registered on the database of the Department of Gastroenterology at Hull Royal Infirmary were approached by letter, advising them of a potential risk of osteoporosis and inviting them to undergo bone densitometry. A total of 81 registered women (60%) attended the Osteoporosis Laboratory, Princess Royal Hospital and underwent dual energy x ray absorptiometry at the lumbar spine (L2-L4) and femoral neck. Historical data relating to the time of diagnosis and adherence to a gluten free diet were obtained. A control group was selected from the local normal population and was first matched for height, weight, and menopausal status. Postmenopausal patients were then further matched to controls of equivalent menopausal age. In coeliac patients, bone mineral density expressed in g/cm2 as mean (SD) was significantly lower at the lumbar spine (1.076 (0.186)) than in the control group (1.155 (0.143), p < 0.001). This was also the case at the femoral neck (0.887 (0.142) versus 0.965 (0.127), p < 0.001). When the coeliac patients were stratified by menopausal status, it was found that femoral neck bone mineral density was significantly below control values in both premenopausal and postmenopausal women. Spinal bone mineral density exhibited a significant decrement only in the postmenopausal group. The age at diagnosis of coeliac disease and adherence to a gluten free diet did not influence bone mineral density at either hip or spine. These results confirm coeliac patients' higher risk of osteopenia. Coeliac disease should be added to the list of medical conditions which constitute an indication for bone densitometry in order that the individual risk of osteoporosis related fracture may be determined.

Balloon or bougie for dilatation of benign esophageal stricture?

Ninety-three adult patients with benign esophageal stricture were randomized to receive balloon or bougie dilatation. Eighty-five patients were eligible for analysis and were followed prospectively for a year. Twenty-four patients required repeat dilatation within a year, but 50 patients completed a year's follow-up without further dilatation. The bougie group initially had a better symptomatic result, experiencing significantly less dysphagia at five months, although this difference had disappeared at one year. Eighteen patients in the balloon group required redilatation for symptoms compared with six in the bougie group. The bougie group had a significantly greater increase in their stricture diameter, and this was still present at one year after dilatation. There was no significant difference in safety or patient acceptability. Balloons are probably more costly to use than bougies. Bougie dilatation is to be preferred to balloon dilatation in adults except in special circumstances.

Comparing the efficacy of cisapride and ranitidine in oesophagitis: a double-blind, parallel group study in general practice

Patients with endoscopically confirmed oesophagitis (n = 49) were treated for 8 weeks with either cisapride (10 mg four times a day) or ranitidine (150 mg twice a day) in a double-blind study in general practice. Mean overall symptom scores fell from 10.8 to 4.5 in the cisapride group and from 9.9 to 4.4 in the ranitidine group over the course of the study. The proportion of patients reporting improvements in individual symptoms in the two treatment groups (cisapride and ranitidine respectively) were: heartburn, 66% and 55%; acid regurgitation, 53% and 47%; epigastric pain, 60% and 52%; satiety, 57% and 47%; bloating, 69% and 71%; belching, 65% and 72%; nausea, 62% and 85%; vomiting, 77% and 66%; poor appetite, 50% and 75%. Improvement in the endoscopic grade of oesophagitis was observed in 66% of patients receiving cisapride and 63% of those receiving ranitidine. It was concluded that cisapride is as effective as ranitidine in relieving the symptoms of oesophagitis and in healing oesophageal erosions.

The effect of propofol anaesthesia on free radical-induced lipid peroxidation in rat liver microsomes

In order to assess the in vivo significance of the free radical scavenging properties of propofol the effect of propofol anaesthesia on the sensitivity of rat liver microsomes to radical-induced lipid peroxidation has been examined. Microsome peroxidation was initiated with a combination of reduced nicotinamide adenine dinucleotide phosphate and ferric ions, and assessed by measuring the changes in oxygen tension in the microsome suspension. In comparison to animals receiving 10% intralipid, saline or midazolam, microsomes prepared from animals anaesthetized with propofol demonstrated a significantly increased resistance to lipid peroxidation. Thus, the median delay in onset of the maximum rate of oxygen consumption in animals receiving a bolus of propofol was 23.1 min (range 14.4-32.3), in comparison to delays in the animals receiving intralipid, saline or midazolam of 1.9 (0.5-4.1), 2.4 (2.0-3.7) and 3.0 (1.8-6.1) min respectively (P < 0.01 in each case, Mann Whitney U-test). More prolonged anaesthesia with either repeated boluses or an infusion of propofol also delayed the onset of lipid peroxidation (45.6 (27.2-60) and 18.3 (9.2-60) min respectively). We conclude that the free radical scavenging properties of propofol are biologically significant at anaesthetic doses.

Oesophagitis is as important as oesophageal stricture diameter in determining dysphagia

It is a common observation that stricture patients with severe dysphagia may have a wide lumen, while others with a narrow stricture have few swallowing complaints. In 64 patients with benign oesophageal stricture the dysphagia score (determined by questionnaire and by a test meal both based on nine different items of food scored according to their solidity) was compared with the diameter of the stricture measured radiologically by premeasured barium spheres. There was evidence of an association, but the correlation coefficient (r) was 0.544 (p = 0.0001), suggesting that the diameter of the stricture is an important, although not the sole, determinant of dysphagia. Stricture diameter explains 29.6% (r2) of variation in dysphagia score. The patients (mean dysphagia score 71 of a maximum possible 90) were divided into three groups according to the severity of oesophagitis (19 patients had minimal, 22 moderate and 23 severe oesophagitis). Analysis revealed the mean dysphagia score to be 83, 73, 59 in each group respectively. Dysphagia score of each group was significantly different from the others (Kruskal-Wallis test). Relating the dysphagia score to stricture diameter for each group gives correlation coefficient r = 0.379 (p = 0.110) in the minimal oesophagitis group, r = 0.651 (p = 0.001) in the moderate group, r = 0.583 (p = 0.004) in the severe group. If both diameter and severity of oesophagitis are included then 66.0% of the variation can be explained. It is concluded that the degree of oesophagitis is as important as luminal diameter in determining swallowing ability.

Advanced trauma life support. A time for reappraisal

The experience of Advanced Trauma Life Support training received by three anaesthetists is discussed with particular reference to the teaching of airway management, the grade of staff who should attend the present courses and the relevance to the British hospital system. We conclude that these courses are useful but limited by their inflexibility and failure to recognise the difference in skill mix in the British setting.

Short report: comparison of two orally administered bowel preparations for colonoscopy--polyethylene glycol and sodium picosulphate

Fifty-nine consecutive patients admitted for colonoscopy were randomized to receive polyethylene glycol or sodium picosulphate. Patients expressed their opinion in a questionnaire and the endoscopists, blinded to the preparation, assessed the cleanliness of different segments of the colon. There was no statistically significant difference in the taste-acceptability of the preparations, frequency of nausea, abdominal pain, peri-anal soreness or sleep disturbance between the two groups. Polyethylene glycol caused vomiting in 13% of patients while this was absent in those who received sodium picosulphate (P less than 0.05). The average number of stools passed was 12.4 in the polyethylene glycol and 8.6 in the sodium picosulphate groups; mean difference 3.8 (95% C.I. 0.7-6.9) with P less than 0.02. The overall cleanliness of the colon was better in the polyethylene glycol group (P = 0.002) as judged by the blinded colonoscopist. There was less delay (P = 0.06) and more completed colonoscopies (P = 0.01) in this group. Polyethylene glycol was a better preparation in all segments of the colon except the rectum. We conclude that polyethylene glycol is the choice of the colonoscopist and should be given to all patients; sodium picosulphate would be a good alternative if patients are intolerant. If a limited colonoscopy or flexible sigmoidoscopy is intended, sodium picosulphate may be preferred because of its acceptable efficacy and slightly advantageous side-effect profile.

Esophageal involvement in Behçet's disease. Is endoscopy necessary?

Twenty patients who were diagnosed as having Behçet's Disease between 1976 and 1990 were asked to attend the dermatology department so that their diagnosis could be reviewed in the light of recently established criteria for the diagnosis of Behçet's disease. Ten patients fulfilled the diagnostic criteria, nine of whom agreed to participate in this endoscopic study. Nine patients underwent upper gastrointestinal endoscopy, three of whom had dyspepsia alone, two had dysphagia and dyspepsia, one had symptoms of acid regurgitation, and the remainder were asymptomatic at the time of endoscopy. One patient had evidence of grade 1 reflux esophagitis, one had an incidental pyloric canal ulcer, and one patient who had severe dysphagia on presentation was found to have a high esophageal stricture with accompanying ulceration. Behçet's disease rarely affects the esophagus but when present can cause marked esophagitis with consequent stricture formation. Since the incidence of esophageal involvement was low (11%), we conclude that unless the patient had marked esophageal symptoms there is no indication for routine endoscopy of patients with Behçet's disease.

A new dysphagia score with objective validation

Patients' accounts of their eating capacity correlate reasonably well with their observed performance, but they do not exactly match each other. This can be attributed to patients' inaccurate estimation of eating ability and the inconstant nature of dysphagia. Therefore, we advocate a combined score in clinical trials. However, for clinical practice, a quantitative assessment of the patient's account is quicker, more convenient, and sufficiently accurate. The advantage of a numerical score is obvious in clinical trials because of its statistical versatility, and may also be desirable in certain cases in clinical practice.

Clinical utility of a saliva alcohol dipstick estimate of serum ethanol concentrations in the emergency department

Rapid determination of serum ethanol concentrations can be a useful adjunct in evaluating patients with decreased levels of consciousness. Previous reports suggest that saliva ethanol concentrations measured by a colorimetric saliva dipstick assay correlate well with serum ethanol concentrations and could be useful in the emergency department. We compared saliva dipstick assay results with concurrent serum ethanol measurements in 67 emergency department patients with altered mental status. Color changes of the stick are calibrated to reflect serum ethanol concentrations of negative (no color change), 4.3 mmol/L, 10.8 mmol/L, 21.7 mmol/L, and greater than or equal to 65.1 mmol/L. Emergency department staff were instructed to conduct the measurement according to the manufacturer's directions and round up equivocal results to the next highest concentration. Serum ethanol concentrations (mean +/- SD) grouped by dipstick results were: negative, 5.2 +/- 13.1 mmol/L; 4.3 mmol/L, 29.1 +/- 18.0 mmol/L; 10.8 mmol/L, 46.6 +/- 27.6 mmol/L; 21.7 mmol/L, 47.0 +/- 18.5 mmol/L; and 65.1 mmol/L, 62.4 +/- 24.2 mmol/L. There were 12 false-negative and 2 false-positive results. Correlation between dipstick results and serum ethanol concentrations was rho = 0.611 (p less than 0.0005). The lack of accuracy of the saliva dipstick measurements and the high number of false-negative results make it a poor choice for determining alcohol use in the emergency department patient.

Enema or Picolax as preparation for flexible sigmoidoscopy?

Two preparations for outpatient flexible sigmoidoscopy, Picolax and Klyx enemas, have been compared in a randomized controlled trial. There was no difference in efficacy between the two preparations, but patients preferred Picolax.

The oesophagus in lichen planus: an endoscopic study

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