Big Data Analysis and Machine Learning in Intensive Care Units

Intensive care is an ideal environment for the use of Big Data Analysis (BDA) and Machine Learning (ML), due to the huge amount of information processed and stored in electronic format in relation to such care. These tools can improve our clinical research capabilities and clinical decision making in the future. The present study reviews the foundations of BDA and ML, and explores possible applications in our field from a clinical viewpoint. We also suggest potential strategies to optimize these new technologies and describe a new kind of hybrid healthcare-data science professional with a linking role between clinicians and data.

"The multimodal approach for ventilator-associated pneumonia prevention"-requirements for nationwide implementation

The multimodal approach for ventilator-associated pneumonia (VAP) prevention has been shown to be a successful strategy in reducing VAP rates in many intensive care units (ICU) in some countries. The simultaneous application of several measures or "bundles" to reduce VAP rates has achieved a higher impact than the progressive implementation of the individual interventions. The ultimate objective of recommendation bundles is their integration in the culture of routine healthcare of the staff in charge of ventilated patients for accomplished rates to persist over time. The noteworthy elements of this new strategy include the selection of the individual recommendations of the bundle, education of care workers (HCW) in the culture of patient safety, audit of compliance with the recommendations, commitment of the hospital management to support implementation, nomination and empowerment of local leaders of the projects in ICUs, both physicians and nurses, and the continuous collection of VAP episodes. The implementation of this new strategy is not an easy task, as both its inherent strength and important barriers to its application have become evident, which need to be overcome for maximal reduction of VAP rates.

Track Analysis of the North, Central, and South American Species of the Epicauta maculata Group (Coleoptera: Meloidae)

We undertook a panbiogeographic analysis of 23 species of the Epicauta maculata group of America-Epicauta abeona Pinto, Epicauta adspersa (Klug), Epicauta andersoni Werner, Epicauta atomaria (Germar), Epicauta apache Pinto, Epicauta cavernosa (Courbon), Epicauta dilatipennis Pic, Epicauta fulvicornis (Burmeister), Epicauta horni Champion, Epicauta jeffersi Pinto, Epicauta koheleri Denier, Epicauta lizeri Denier, E. maculata (Say), Epicauta magnomaculata Martin, Epicauta minutepunctata Borchmann, Epicauta nigropunctata (Blanchard), Epicauta normalis Werner, Epicauta ocellata (Dugès), Epicauta pardalis LeConte, picauta phoenix Werner, Epicauta pluvialis Borchmann, Epicauta proscripta Werner, Epicauta rubella Denier, and Epicauta ventralis Werner-with the purpose of analyzing the distributional data for taxa, to establish patterns of distribution of an ancestral biota and areas where these groups have interacted. Based on the overlap of 20 individual tracks, four generalized tracks constituted by different numbers of species were identified; two of them are located in the Nearctic region and the Mexican transition zone (tracks "A" and "B"), and the other two are distributed in the Neotropical region and the South America transition zone ("C", "D"). Six nodes were recognized: Two of them are included in the Nearctic Region, node 'I' located in northern USA and node 'II' located in southwestern USA, both at the intersection of the tracks "A" and "B". The other four are included in the Neotropical Region at the intersection of the tracks "C" and "D": Node 'III' is located in Chaco province; node 'IV' is located in Parana Forest province; node 'V' is located in the northwest of Argentina in Puna province, and node 'VI' is located in Monte province.

Guidelines for the prevention of ventilator-associated pneumonia and their implementation. The Spanish "Zero-VAP" bundle

BACKGROUND

"Zero-VAP" is a proposal for the implementation of a simultaneous multimodal intervention in Spanish intensive care units (ICU) consisting of a bundle of ventilator-associated pneumonia (VAP) prevention measures.

METHODS/DESIGN

An initiative of the Spanish Societies of Intensive Care Medicine and of Intensive Care Nurses, the project is supported by the Spanish Ministry of Health, and participation is voluntary. In addition to guidelines for VAP prevention, the "Zero-VAP" Project incorporates an integral patient safety program and continuous online validation of the application of the bundle. For the latter, VAP episodes and participation indices are entered into the web-based Spanish ICU Infection Surveillance Program "ENVIN-HELICS" database, which provides continuous information about local, regional and national VAP incidence rates. Implementation of the guidelines aims at the reduction of VAP to less than 9 episodes per 1000 days of mechanical ventilation. A total of 35 preventive measures were initially selected. A task force of experts used the Grading of Recommendations, Assessment, Development and Evaluation Working Group methodology to generate a list of 7 basic "mandatory" recommendations (education and training in airway management, strict hand hygiene for airway management, cuff pressure control, oral hygiene with chlorhexidine, semi-recumbent positioning, promoting measures that safely avoid or reduce time on ventilator, and discouraging scheduled changes of ventilator circuits, humidifiers and endotracheal tubes) and 3 additional "highly recommended" measures (selective decontamination of the digestive tract, aspiration of subglottic secretions, and a short course of iv antibiotic).

DISCUSSION

We present the Spanish VAP prevention guidelines and describe the methodology used for the selection and implementation of the recommendations and the organizational structure of the project. Compared to conventional guideline documents, the associated safety assurance program, the online data recording and compliance control systems, as well as the existence of a pre-defined objective are the distinct features of "Zero VAP".

[Debates in intensive medicine: Pro: selective decontamination]

Selective decontamination of the digestive tract (SDD) has been proven to prevent infections of endogenous development and reduce mortality in critically ill patients under prolonged mechanical ventilation. Historical arguments against its use, like the development of bacterial resistance or the selection of resistant microorganisms and the absence of influence on mortality have not been confirmed. Moreover, recent clinical trials designed to evaluate these variables, show remarkable reductions in the incidence of resistant bacteria and a significant beneficial effect on mortality. Furthermore, no increases in workload or costs have been documented. A few studies with post-trial and intermediate range follow-up periods didn't find increases in resistance. Implementation of SDD requires motivation and leadership in order to achieve cooperation of other related hospital specialists, training of several categories of healthcare professionals, and continuous monitoring of results. In order to facilitate the use of SDD in the critically ill, this preventive measure should be incorporated in guidelines of national and international scientific societies and working groups involved in the care of the critically ill patient. The general implementation of SDD in our intensive care units must be accompanied by a registry in order to be able to monitor the effect on the incidence of infection and bacterial resistance. For this purpose, the Spanish national ICU infection and resistance surveillance programme ENVIN-HELICS, active over the last 15 years, constitutes both a more than adequate tool, and the convenient reference data base.

Automated effective dose estimation in CT

European regulations require the dose delivered to patients in CT examinations to be monitored and checked against reference levels. Dose estimation has traditionally been performed manually. This is time consuming and therefore it is typically performed on just a few patients and the results extrapolated to the general case. In this work an automated method to estimate the dose in CT studies is presented. The presented software downloads CT studies from the corporative picture archiving and communication system and uses the information on the DICOM headers to perform the dose calculation. Automation enables dose estimations to be performed on a larger fraction of studies, enabling more significant comparisons with diagnostic reference levels (DRLs). A preliminary analysis involving 5800 studies is presented with details of dose distributions for selected CT protocols in use at a university hospital. Average doses are compared with DRLs. Effective dose estimations are also compared with estimations based on the dose length product.

Study and evaluation of the Siemens virtual wedge factor: dosimetric monitor system and variable field effects

In the year 1997 Siemens introduced the virtual wedge in its accelerators. The idea was that a dose profile similar to that of a physical wedge can be obtained by moving one of the accelerator jaws at a constant speed while the dose rate is changing. This work explores the observed behaviour of virtual wedge factors. A model is suggested which takes into account that at any point in time, when the jaw moves, the dose at a point of interest in the phantom is not only due to the direct beam. It also depends on the scattered radiation in the phantom, the head scatter and the behaviour of the monitoring system of the accelerator. Measurements are performed in a Siemens Primus accelerator and compared to the model predictions. It is shown that the model agrees reasonably well with measurements spanning a wide range of conditions. A strong dependence of virtual wedge factors on the dosimetric board has been confirmed and an explanation has been given on how the balance between different contributions is responsible for virtual wedge factors values.

[Effect of the availability of a medicalized mobile ICU (MMICU) on the hospital admissions after an out-of-hospital cardiorespiratory arrest (OH-CRA)]

Patients admitted in an ICU after OH-CRA before and after the implementation of a MMICU were evaluated. During a period of 11 years, divided into a pre-MMICU period (1988-1993) and a post-MMICU period (1994-1998), 39 patients were admitted in the pre period and 64 patients in the post period. The basal characteristics, the etiologies of OH-CRA and of death in ICU they were similar. The incidence of severe anoxic encephalopathy (SAE) it doubled in the post period. There were not significant differences both to the discharge from ICU and to the hospital discharge. We conclude that after implementing a MMICU more patients are admitted in ICU resuscitated after OH-CRA. The survival does not vary, but the incidence of SAE increases.

Determination of zinc (II) in pharmaceuticals based on a flow-through bulk optode

A method based on flow injection (FI), was applied for the determination of Zn (II) using a flow-through bulk optode membrane that incorporates 1-(2-pyridylazo)-2-naphthol in a plasticized poly (vinyl chloride) membrane entrapped in a cellulose support. The calibration graph plotting the reflectance at 562 nm versus [Zn (II)] was linear in the range 0.16-3.27 mgl(-1) (2.5 x 10(-6)-5 x 10(-5) M) with a detection limit of 0.10 mgl(-1). The variation coefficients of the sensor response for 0.33 mgl(-1) of Zn (II) were +/-0.11% for consecutive measurements (n=10), +/-0.19% between days (n=5) and +/-0.22% between different membranes (n=6). The sensor can be readily regenerated with the same acetic/acetate carrier of pH 3.9. The FI method proposed was applied to the determination of zinc (II) in pharmaceuticals.

[Development of pre-hepatic portal hypertension of the rat]

OBJECTIVE

A long-term study of the prehepatic portal hypertension model by triple stenosing ligation of the portal vein in the rat.

METHOD

A cluster analysis of the animals in the different evolutive stages of portal hypertension (1 1/2, 6, 12 and 14 months) has been carried out. This analysis has made it possible to identify three homogeneous groups (A, B and C) in relationship to the liver weight.

RESULTS

The animals with liver atrophy (group C) show a decrease of body, splenic and testicular weights as well as a higher development of the portosystemic collateral circulation in relation to the A and B groups.

CONCLUSION

The percentage of animals belonging to the group C decrease progressively during the evolution of portal hypertension and those animals corresponding to the group A, in which is superior the liver weight, increase, while the B group does not change.

Development of a new flow-through bulk optode for the determination of manganese(II)

A flow-through bulk optode based on the use of 1-(2-pyridylazo)-2-naphthol (PAN) immobilized in a plasticized poly(vinyl chloride) membrane entrapped in a cellulose support, in conjuntion with the flow injection analysis technique, is proposed for the determination of manganese(II). The calibration graph obtained at 570 nm was linear in the range 0.27-27.5 mg L(-1) (5 x 10(-6)-5 x 10(-4) M) Mn(II) with a detection limit of 0.18 mg L(-1). The coefficients of variation of the sensor response for 5.5 mg L(-1) of Mn(II) were +/-0.22% for consecutive measurements (n = 10), +/-0.48% between days (n = 5) and +/-0.38% between different membranes (n = 6). The sensor was readily regenerated with the carrier acetic acid/acetate buffer of pH 4.5. The method was applied to the determination of manganese in steels, waters and lemon tree leaves.

Spectrophotometric methods for determining meloxicam in pharmaceuticals using batch and flow-injection procedures

Two sensitive and fast spectrophotometric methods using batch and flow-injection procedures for the determination of meloxicam (MX) are proposed. The methods are based on the formation of a green complex between this drug and Fe(III) [2MX/Fe(III)] in a methanolic medium. The calibration graphs resulting from measuring the absorbance at 570 nm are linear over the ranges 2.0-200 and 5.00-250 mg l(-1) with detection limits of 0.47 and 0.72 mg l(-1), respectively. Furthermore, a flow-injection spectrophotometric method involving measurement of the absorbance of the drug at 362 nm in 0.1 M NaOH is presented. The calibration graph is linear over the range 0.5-20 mg l(-1) with a detection limit of 0.04 mg l(-1). The methods are applied to the routine analysis of MX in pharmaceuticals.

Flow-injection spectrophotometric methods for the determination of tenoxicam

Two sensitive and rapid flow-injection spectrophotometric methods are proposed for the determination of tenoxicam (TX). In the first method, a Fe(III)-tenoxicam complex is formed in a methanolic medium and the absorbance is measured at 540 nm, while the second method involves measurement of the absorbance at 355 nm of a solution containing the drug in hydrochloric acid medium. In both methods, the peak heights were proportional to tenoxicam concentration over the ranges 7.0-320 and 0.5-8.5 mg/l(-1), respectively. The methods have been applied to the routine determination of the drug in dosage forms.

[Electro-clinical and neuroimaging studies in epilepsy in elderly patients]

INTRODUCTION

Due to the aging population in developed countries, epidemiological studies show an increasing tendency to the prevalence of epilepsy in the elderly.

PATIENTS AND METHODS

During 54 months, we have studied the electroclinical and neuroimaging features in outpatients older than 60, with active epilepsy. Every patient was interviewed by one of the authors. Then, we have reviewed the medical records about the clinical features, EEG and neuroimaging (NI) studies and seizures frequency (SF) outcome. Differences in crude proportions were assessed by chi 2 test for independence by 2 x 2 tables.

RESULTS

The study was been performed in 78 patients with 70.3 +/- 7.3 years of mean age at review. Partial seizures were significantly related with an higher SF at onset and, in the series of complex partial seizures was more frequent a temporal EEG topography. There was predominance of men, NI abnormal, symptomatic etiology and SF at onset > or = 1 by day in that patients who started their epilepsy after 60 years. A 51.3% was seizures-free in the last year and in 80% the SF was improved a 50% or more from the beginning.

CONCLUSION

A significantly greater percentage of patients remained with seizures in four cases: in those with a SF at onset greater than 1 every day, in those suffering complex partial seizures, in women and in patients with temporal EEG topography.

[The consumption of tobacco, alcohol and other drugs by adolescent Spanish students]

OBJECTIVES

This study was undertaken in the mid-1990s (1994) to describe the use of tobacco, alcohol, and non-institutionalized drugs among pre-adolescent and adolescent Spanish students.

METHODS

Information was collected within the framework of a periodic transversal study of life styles among European students, with particular emphasis on health-related habits. In the current study we present the results of the last survey carried out in Spain within the context of this study (1994), which involved a representative sample of Spanish students 11, 13, 15, 17 and 18 years-old (n = 6,711). An anonymous questionnaire was completed by the students in class. The survey sampling uses proportionate stratification and multistage sampling.

RESULTS

In 1994, 49% of the Spanish students in this age group had tried tobacco. Twenty-four percent were sporadic or regular smokers. There was a large proportion of female smokers than male smokers (27% vs 20%). The overall proportion of smokers increased from 3% at 11 years to 47% at 18 years. One third (33%) of the 18-year-old students smoked daily. Eighty-four percent of the students of this age indicated that they had tried one or more types of alcoholic beverage. Twenty-one percent consumed alcohol regularly (at least once a week). Regular alcohol use was somewhat more common among males (24%) than among females (19%). Forty-six percent of the 18-year-old students consumed alcoholic beverages regularly and 66% had been intoxicated one or more times. Almost one fifth (18%) of the 13-to-18 year-old students indicated that they had tried some type of non-institutionalized drug, although the current rate of consumption was 8%. Cannabis was the drug most frequently tried (18%) and the drug most often consumed at present (8%), followed by cocaine and heroin. More males than females had tried non-institutionalized drugs.

DISCUSSION

Analysis of the data revealed that adolescent tobacco use is increasingly frequent among females. Alcohol use continues to be widespread among Spanish pre-adolescents and adolescents. Alcohol use begins in childhood and becomes consolidated in adolescence. The results suggest, in relation to gender differences in the use of tobacco, alcohol, and non-institutionalized drugs, that there is a strong tendency toward the homogenization of these habits between genders. It is necessary to emphasize the preventive measures of drug dependence among Spanish pre-adolescents and adolescents.

Effectiveness and cost of selective decontamination of the digestive tract in critically ill intubated patients. A randomized, double-blind, placebo-controlled, multicenter trial

We evaluated the effect of selective decontamination of the digestive tract (SDD) on the incidence of ventilator-associated pneumonia (VAP) and its associated morbidity and cost in a mixed population of intubated patients. Two hundred seventy-one consecutive patients admitted to the intensive care units (ICUs) of five teaching hospitals and who had an expected need for intubation exceeding 48 h were enrolled and received topical antibiotics or placebo. Uninfected patients additionally received ceftriaxone or placebo for 3 d. VAP occurred in 11.4% of SDD-treated and 29.3% of control-group patients (p < 0.001; 95% confidence interval [CI]: 7.8 to 27.9). The incidence of nonrespiratory infections in the two groups was 19.1% and 30.7%, respectively (p = 0.04; 95% CI: 0.7 to 22.7). Among survivors, the median length of ICU stay was 11 d (interquartile range: 7 to 21.5 d) for the SDD-treated group and 16. 5 d (10 to 30 d) for the control group (p = 0.006). Mean cost per survivor was $11,926 for treated and $16,296 for control-group patients. Mortality was 38.9% and 47.1%, respectively (p = 0.57). In decontaminated patients, the prevalence of gram-negative bacilli fell within 7 d from 47.4% to 13.0% (p < 0.001), whereas colonization with resistant gram-positive strains was higher (p < 0. 05) than in the placebo group. In a mixed population of intubated patients, SDD was associated with a significant reduction of morbidity at a reduced cost. Our findings support the use of SDD in this high-risk group.

Simultaneous determination of piroxicam and its major metabolite 5'-hydroxypiroxicam in human plasma by derivative spectrophotometry

A first-derivative spectrophotometric method for the simultaneous determination of piroxicam (PX) and its major metabolite 5'-hydroxypiroxicam (OH PX) in human plasma is described. The method consists of direct extraction of the two drugs from the plasma samples with hydrochloric and trichloroacetic acid prior to their determination by measuring the first-derivative signals at 337.0 nm for PX and at 327.0 nm for OHPX (zero-crossing wavelength). The calibration graphs were linear up to 10.0 and 8.0 mg l-1 of PX and OH PX, respectively, and the limits of quantification were 0.27 and 0.56 mg l-1. The possible interfering effects of other substances were studied.

Flow-injection spectrophotometric determination of diclofenac sodium in pharmaceuticals and urine samples

A sensitive and fast flow-injection spectrophotometric method for the determination of diclofenac sodium based on the formation of coloured compound with Ce(IV)-3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) in H2SO4 3 x 10(-2) M medium is proposed. Using the peak height as a quantitative parameter diclofenac was determined at 580 nm over the range 0.20-8.0 micrograms ml-1. The proposed method was successfully applied to the determination of diclofenac in pharmaceuticals and urine samples.

Spectrophotometric methods for the determination of cephradine or ceftazidine in human urine using batch and flow-injection procedures

Sensitive and fast spectrophotometric methods for the determination of cephradine or ceftazidine in human urine, based on the formation of compounds between these drugs and Pd(II), are described. In the batch procedures the calibration graphs resulting from the measurement of the absorbance at 330 nm is linear over the range 5.0-60.0 micrograms. ml-1 for cephradine and 3.0-60.0 micrograms ml-1 for ceftazidine. The methods were successfully adapted to FI-systems, the peak heights being proportional to cephalosporin concentration over the range 5.0-60.0 micrograms ml-1 for cephradine and 3.0-60.0 micrograms ml-1 for ceftazidine. The sampling frequency was 60 h-1 with a sample injection of 72 microliters.

Flow-injection spectrophotometric determination of frusemide or sulphathiazole in pharmaceuticals

Two sensitive and fast flow-injection spectrophotometric methods are proposed for the determination of frusemide or sulphathiazole based on the formation of coloured complexes between these compounds and Pd(II) at pH 5.0 and 55 degrees C. Using the peak height as a quantitative parameter, frusemide or sulphathiazole was determined at 410 nm over the range 2.0 x 10(-5)-4.0 x 10(-4) M or 5.0 x 10(-5)-3 x 10(-4) M, respectively. The methods were applied to the determination of these sulphonamides in pharmaceuticals.

Myocardial infarction and cardiovascular risk factors in Mexico City and San Antonio, Texas

Because the epidemiology of cardiovascular disease in Mexico is largely unknown, we examined the prevalence of cardiovascular risk factors and myocardial infarction (MI) in adults from low-income colonias in Mexico City. Data were collected as part of the Mexico City Diabetes Study, a population-based survey of diabetes and cardiovascular disease conducted between 1987 and 1992. Results were compared with those obtained from a comparable survey conducted previously among low-income Mexican Americans in San Antonio, Tex. A total of 2271 individuals between the ages of 35 and 64 years from Mexico City and 1143 adults of the same age range from San Antonio were studied. Despite being leaner and having lower levels of total cholesterol, Mexicans in Mexico City had markedly higher levels of triglycerides (P < .001) and lower levels of HDL cholesterol (P < .001) than Mexican Americans in San Antonio. MI was assessed by Minnesota-coded electrocardiograms and by a self-reported history of physician-diagnosed heart attack. In men, the prevalence of self-reported heart attack was significantly higher in San Antonio than in Mexico City (odds ratio, 5.85; P < .001), and in women, the prevalence of electrocardiogram-documented MI was significantly higher in San Antonio than Mexico City (odds ratio, 2.51; P < .001). The apparent excess of MI in San Antonio relative to Mexico City could be due to higher case-fatality in Mexico City or to a higher incidence in San Antonio.

Determination of captopril in pharmaceutical samples by flow injection analysis

A flow injection spectrophotometric method for the determination of captopril involving measurement of the absorbance of the captopril complex with palladium(II) in a 0.12 M HCl medium at 400 nm is presented. The calibration graph was linear over the range 2 x 10(-5)-6 x 10(-4) M. The sampling frequency was 90 h-1 with sample injections of 70 microliters. The proposed method was applied to the determination of captopril in pharmaceutical samples.

Circulating immune complexes in breast and lung cancer, before and after chemotherapy

Circulating immune complexes (CIC) levels were evaluated in two groups of cancerous patients to try to correlate CIC levels, tumor stage and chemotherapy received. There were 40 patients with Lung Cancer (LC) clinical stages III and IV; 60 patients with Breast Cancer (BC) stages II, III and IV and 38 normal controls. LC patients showed significant increase in CIC values before, during and after treatment as compared to controls, without any difference among groups under different treatment combinations and tumor stage. Stage II BC patients showed decreased CIC levels during treatment (p less than 0.01 vs initial value). This decrease was maintained after treatment (p less than 0.02). Stage III BC patients showed different behaviour according to treatment: those who only received chemotherapy (ADM + CTX) showed no significant differences during treatment, and those treated with ADM + CTX and megestol acetate (MA) displayed decreased CIC levels after treatment (p less than 0.05) reaching similar control values. Stage IV patients treated with ADM + CTX + MA returned to normal CIC values during treatment. These results proved that combined treatment of chemotherapy and hormone therapy diminished CIC levels in BC patients, while therapy given to LC patients did not present any modifications.

[Effect of BCG on the growth rate of Sarcoma in normal and splenectomized mice]

A study was carried out on the growth of Sarcoma 180 alone or mixed with BCG in normal and splenectomized BALB/c mice, with or without previous immunization with BCG intradermally (id), 40 days before tumor challenge. No survival was observed in non splenectomized mice inoculated with Sarcoma 180, both in normal mice and in those previously treated with BCG, whereas the inoculation of Sarcoma 180 mixed with BCG produced a 37 % increase in the survival rate in normal animals and an 83 % increase in the group previously treated with BCG. In splenectomized mice the survival rate was 56 % in those inoculated with Sarcoma 180 alone, rising to 100 % in the group inoculated with Sarcoma 180 mixed with BCG. Previous immunization with BCG in splenectomized animals did not affect tumor incidence significantly. These results suggest the participation of the spleen in the mechanism of tumoral rejection favoured by BCG inoculation.