Papers by Felix Hernandez
Journal of AOAC INTERNATIONAL, 2006
A gas chromatography/negative chemical ionization-mass spectrometry (GC/NCI-MS) method has been d... more A gas chromatography/negative chemical ionization-mass spectrometry (GC/NCI-MS) method has been developed for the simultaneous determination of the fungicides captan and folpet in khaki (persimmon; flesh and peel) and cauliflower. Samples were extracted with acetone in the presence of 0.1 M zinc acetate solution in order to avoid degradation of fungicides and were purified using solid-phase extraction with divinylbenzene polymeric cartridges. Purified extracts were evaporated and dissolved in hexane prior to injection into the GC/NCI-MS system. Isotope-labeled captan and folpet were used as surrogate/internal standards, and quantification was performed using matrix-matched calibration. The method showed linear response in the concentration range tested (50-2500 ng/mL). The method was fully validated with untreated blank samples of khaki (flesh and peel) and cauliflower spiked at 0.05 and 0.5 mg/kg. Satisfactory recoveries between 82 and 106% and relative standard deviations lower th...
Determination of 17 beta-estradiol and 17 alpha-ethinylestradiol in water at sub-ppt levels by liquid chromatography coupled to tandem mass spectrometry
Analytical Methods, 2014
ABSTRACT Steroid estrogens are a group of endocrine disrupting compounds (EDCs) excreted in human... more ABSTRACT Steroid estrogens are a group of endocrine disrupting compounds (EDCs) excreted in human urine mainly as glucuronide or sulfate conjugates, which might be converted back into the free estrogens in water. The natural estrogen 17β-estradiol (E2) and the synthetic one 17α-ethinylestradiol (EE2) are of particular concern due to their strong estrogenic activity. The main environmental source of estrogen exposure is treated wastewaters, with the associated risk of releasing these pollutants to surface waters and even reaching finished drinking waters. In this work, we have developed and validated (at 0.1 and 1 ng L−1 levels) a robust and sensitive method based on Ultra-High Performance Liquid Chromatography (UHPLC) coupled to MS/MS for the reliable identification and quantification of E2 and EE2 in surface waters. Several sulfate conjugates have been also included into the methodology. A pre-concentration step based on off-line solid-phase extraction with Oasis HLB cartridges has been optimized prior to the UHPLC-(ESI)MS/MS determination with a last-generation triple quadrupole analyzer. Two isotope-labelled analytes (E2-d4 and EE2-d4) have been used as surrogate standards to ensure an accurate quantification, achieving very low limits of detection for E2 (0.06 ng L−1) and EE2 (0.02 ng L−1). Several surface waters and influents and effluents from wastewater treatment plants have been analyzed to test the method applicability.
Rapid non-target screening of organic pollutants in water by ultraperformance liquid chromatography coupled to time-of-light mass spectrometry
TrAC Trends in Analytical Chemistry, 2008
We show the potential of ultra-performance liquid chromatography (UPLC) coupled to time-of-flight... more We show the potential of ultra-performance liquid chromatography (UPLC) coupled to time-of-flight mass spectrometry (TOF-MS) for screening of non-target organic pollutants in water samples. The great accuracy and the resolution provided by a TOF analyzer allow the mass of any ionizable component in a sample to be accurately measured.Efficient screening applied to environmental samples should ideally detect as many pollutants
Steroids, 2009
The applicability of LC-MS/MS in precursor ion scan mode for the detection of urinary stanozolol ... more The applicability of LC-MS/MS in precursor ion scan mode for the detection of urinary stanozolol metabolites has been studied. The product ion at m/z 81 has been selected as specific for stanozolol metabolites without a modification in A-or N-rings and the product ions at m/z 97 and 145 for the metabolites hydroxylated in the N-ring and 4-hydroxy-stanozolol metabolites, respectively. Under these conditions, the parent drug and up to 15 metabolites were found in a positive doping test sample. The study of a sample from a chimeric uPA-SCID mouse collected after the administration of stanozolol revealed the presence of 4 additional metabolites. The information obtained from the product ion spectra was used to develop a SRM method for the detection of 19 compounds. This SRM method was applied to several doping positive samples. All the metabolites were detected in both the uPA-SCID mouse sample and positive human samples and were not detected in none of the blank samples tested; confirming the metabolic nature of all the detected compounds. In addition, the application of the SRM method to a single human excretion study revealed that one of the metabolites (4,16-dihydroxy-stanozolol) could be detected in negative ionization mode for a longer period than those commonly used in the screening for stanozolol misuse (3-hydroxy-stanozolol, 16-hydroxy-stanozolol and 4-hydroxy-stanozolol) in doping analysis. The application of the developed approach to several positive doping samples confirmed the usefulness of this metabolite for the screening of stanozolol misuse. Finally, a tentative structure for each detected metabolite has been proposed based on the product ion spectra measured with accurate masses using UPLC-QTOF MS.
Rapid Communications in Mass Spectrometry, 2010
Journal of Mass Spectrometry, 2013
'Legal highs' are novel substances which are intended to elicit a psychoactive response. They are... more 'Legal highs' are novel substances which are intended to elicit a psychoactive response. They are sold from 'head shops', the internet and from street suppliers and may be possessed without legal restriction. Several months ago, a 19-year-old woman came searching for medical treatment as she had health problems caused by smoking legal highs. The substances were sold as herbal blends in plastic bags under four different labels. In this work, samples of these herbal blends have been analysed to investigate the presence of psychoactive substances without any reference standard being available at the laboratory. A screening strategy for a large number of synthetic and natural cannabinoids has been applied based on the use of ultra-high pressure liquid chromatography coupled to quadrupole-time of flight mass spectrometry (UHPLC-QTOF MS) under MS E mode. A customized home-made database containing literature-based exact masses for parent and product ions of around 200 synthetic and natural cannabinoids was compiled. The presence of the (de)protonated molecule measured at its accurate mass was evaluated in the samples. When a peak was detected, collision-induced dissociation fragments and characteristic isotopic ions were also evaluated and used for tentative identification. After this tentative identification, four synthetic cannabinoids (JWH-081, JWH-250, JWH-203 and JWH-019) were unequivocally confirmed by subsequent acquisition of reference standards. The presence in the herbal blends of these synthetic cannabinoids might explain the psychotic and catatonic symptoms observed in the patient, as JWH compounds could act as potent agonists of CB 1 and CB 2 receptors located in the Limbic System and Basal ganglia of the human brain. Copyright
Journal of Chromatography A, 1999
A multiresidue method based on normal-phase LC for the sample clean up of whale tissues extracts ... more A multiresidue method based on normal-phase LC for the sample clean up of whale tissues extracts prior to GC-MS determination of residues of polychlorinated biphenyls, organochlorine pesticides and derivatives and lipophylic organophosphorus pesticides has been developed. Pesticides were extracted from blubber by fusing and dissolving the fat in n-hexane and from liver and kidney by reflux in n-hexane. Hexanic extracts were directly injected on the silicagel column of the automated LC clean up system, using n-hexane as mobile phase. Diode array detection allowed the on-line monitoring of lipids elution from the LC system. Purified extracts were analysed by GC using mass selective detection. The developed procedure was applied to different tissues from a whale specimen appeared in the Valencian coast, finding high 21 21 concentrations of OCs (up to 7.3 mg g pp'-DDE, and 7.2 mg g PCBs). The method was validated by means of recovery tests for all the compounds detected in the whale and also for some other OCs and OPs studied in this paper. The method improves other current methods for the analysis of persistent organochlorines in marine mammals with regard to time of analysis, solvent expend and automation; solvent exchanges are not necessary before GC analysis, and it allows the simultaneous determination of organophosphorus pesticides.
Journal of Chromatography A, 2009
An ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has be... more An ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed for the simultaneous quantification and confirmation of 11 basic/acidic illicit drugs and relevant metabolites in surface and urban wastewater at ng/L levels. The sample pre-treatment consisted of a solid-phase extraction using Oasis MCX cartridges. Analyte deuterated compounds were used as surrogate internal standards (except for norbenzoylecgonine and norcocaine) to compensate for possible errors resulting from matrix effects and those associated to the sample preparation procedure. After SPE enrichment, the selected drugs were separated within 6 min under UHPLC optimized conditions. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyzer (TQD from Waters) in positive-ion mode (ESI+) was used. The excellent selectivity and sensitivity of the TQD analyzer in selected reaction monitoring mode allowed quantification and reliable identification at the LOQ levels. Satisfactory recoveries (70-120%) and precision (RSD < 20%) were obtained for most compounds in different types of water samples, spiked at two concentration levels [limit of quantification (LOQ) and 10LOQ]. Thus, surface water was spiked at 30 ng/L and 300 ng/L (amphetamine and amphetamine-like stimulants), 10 ng/L and 100 ng/L (cocaine and its metabolites), 300 ng/L and 3000 ng/L (tetrahydrocannabinol-COOH). Recovery experiments in effluent and influent wastewater were performed at spiking levels of three and fifteen times higher than the levels spiked in surface water, respectively. The validated method was applied to urban wastewater samples (influent and effluent). The acquisition of three selected reaction monitoring transitions per analyte allowed positive findings to be confirmed by accomplishment of ion ratios between the quantification transition and two additional specific confirmation transitions. In general, drug consumption increased in the weekends and during an important musical event. The highest concentration levels were 27.5 g/L and 10.5 g/L, which corresponded to 3,4-methylenedioxymethamphetamine (MDMA, or ecstasy) and to benzoylecgonine (a cocaine metabolite), respectively. The wastewater treatment plants showed good removal efficiency (>99%) for low levels of illicit drugs in water, but some difficulties were observed when high drug levels were present in wastewaters.
Journal of Chromatography A, 2012
Microcystins and nodularin are cyclic peptides hepatotoxins produced by cyanobacterial genera (bl... more Microcystins and nodularin are cyclic peptides hepatotoxins produced by cyanobacterial genera (bluegreen algae). Toxic cyanobacterial blooms are a worldwide problem, as reported in several countries, like China, Australia, or the United States. Therefore, it is necessary to develop sensitive and reliable analytical methodology to determine this type of toxins in water at parts per billion levels, or even lower. In this work, the potential of solid-phase extraction coupled on-line to ultra-high-pressure liquid chromatography/electrospray tandem mass spectrometry (SPE-UHPLC-MS/MS) has been investigated for the efficient quantification and confirmation of microcystins LR, RR, YR, LY, LW, LF and nodularin in surface and drinking water samples, at sub-ppb levels. The method developed involves the injection of only 1 mL of water sample into the on-line SPE-UHPLC-MS/MS system and allows the rapid determination of the compounds selected (8 min of chromatographic run), avoiding laborious sample treatment. The method was validated in surface and drinking water by means of recovery experiments at 0.25 and 1 g L −1. Average recoveries (n = 5) ranged from 71 to 116%, with relative standard deviations (RSDs) lower than 15%. For microcystins LR, RR, YR and nodularin, a third level was also assayed (0.1 g L −1) obtaining satisfactory data too. Limits of detection between 0.002 and 0.0405 g L −1 were estimated (0.0005 g L −1 for nodularin). The developed method was applied to the analysis of water samples collected in the province of Castellón (Spain). The acquisition of three MS/MS transitions for each compound allowed the unequivocal confirmation of positive samples, which was supported by the accomplishment of ion intensity ratios and retention time when compared with reference standards.
Journal of Agricultural and Food Chemistry, 2012
Laboratories devoted to the public health field have to face the analysis of a large number of or... more Laboratories devoted to the public health field have to face the analysis of a large number of organic contaminants/residues in many different types of samples. Analytical techniques applied in this field are normally focused on quantification of a limited number of analytes. At present, most of these techniques are based on gas chromatography (GC) or liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS). Using these techniques only analyte-specific information is acquired, and many other compounds that might be present in the samples would be ignored. In this paper, we explore the potential of time-of-flight (TOF) MS hyphenated to GC or LC to provide additional information, highly useful in this field. Thus, all positives reported by standard reference targeted LC−MS/MS methods were unequivocally confirmed by LC−QTOF MS. Only 61% of positives reported by targeted GC−MS/MS could be confirmed by GC−TOF MS, which was due to its lower sensitivity as nonconfirmations corresponded to analytes that were present at very low concentrations. In addition, the use of TOF MS allowed searching for additional compounds in large-scope screening methodologies. In this way, different contaminants/residues not included in either LC or GC tandem MS analyses were detected. This was the case of the insecticide thiacloprid, the plant growth regulator paclobutrazol, the fungicide prochloraz, or the UV filter benzophenone, among others. Finally, elucidation of unknowns was another of the possibilities offered by TOF MS thanks to the accurate-mass full-acquisition data available when using this technique.
Quantification and confirmation of priority organic micropollutants in water by LC-tandem mass spectrometry
International Journal of Environmental Analytical Chemistry, 2007
ABSTRACT Liquid chromatography coupled to tandem mass spectrometry with a triple quadrupole analy... more ABSTRACT Liquid chromatography coupled to tandem mass spectrometry with a triple quadrupole analyser was used to determine selected (medium) polar organic pollutants—isoproturon, diuron and pentachlorophenol, as the herbicides simazine, atrazine, terbuthilazine, alachlor, and metolachlor—in treated water from urban solid-waste leachates. Two millilitres of water was preconcentrated by on-line trace enrichment (solid-phase extraction liquid chromatography) which allowed rapid analysis, but still with a satisfactory sensitivity, as the limits of quantification were 0.05 µg L, while the limits of detection were in the range of 0.001–0.01 µg L. Confirmation of the identity of compounds was ensured by the use of two tandem mass spectrometry transitions. Moreover, a study of matrix effects was thoroughly investigated by applying the developed procedure to different ground and surface waters. A simple dilution of the water sample with high-performance-liquid-chromatography-grade water was sufficient to minimize and/or remove this undesirable effect in all water samples tested, this approach being feasible due to the excellent sensitivity of the method.
International Journal of Environmental Analytical Chemistry, 2008
An overview is given on the presence and changes over time of pesticide residues in groundwater f... more An overview is given on the presence and changes over time of pesticide residues in groundwater from the Valencia region, one of the most important citrus cultivation sites of southern Europe. A multiresidue LC-MS/MS method was applied for the screening of around 50 pesticides in 75 water samples collected during 2000. The herbicides simazine, terbuthylazine, bromacil, terbumeton, and diuron were the most frequently detected compounds. On the basis of compounds detected in these samples, another method that focused on 30 herbicides and relevant transformation products (TPs) was developed and applied to around 80 water samples collected during 2003. Simazine was the most frequently found compound followed by several triazine metabolites. Data for this paper show the vulnerability of groundwater in this area to herbicide applications and illustrate the importance of including pesticide TPs in environmental monitoring programmes, as four out of the five compounds most frequently detected were pesticide TPs.
Food Chemistry, 2014
Veterinarian and human pharmaceuticals may be intentionally added to animal feed to enhance anima... more Veterinarian and human pharmaceuticals may be intentionally added to animal feed to enhance animal production. Monitoring these substances is necessary for protecting the consumers. In this work, a screening method covering 116 human and veterinary drugs has been developed and validated in five types of animal feed at 0.02 and 0.2 mg kg-1. After a simple extraction with acetonitrile (1% formic acid) and subsequent tenfold dilution with water, the sample extracts were analyzed by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Nearly all compounds tested were detected at 0.02 mg kg-1, based on the presence of the accurate-mass protonated molecule. The reliable identification of the compound using a second accurate-mass (fragment) ion was however more problematic at this level due to the lower abundance of the second ion in the mass spectra. In a subsequent step, the procedure was applied to 22 feed samples, where compounds as trimethoprim, robenidine, or -and β-nandrolone were detected and identified. The potential applicability of the method to quantitative analysis of the compounds detected in the samples was also evaluated.
Analytical Chemistry, 2007
Figure 6. Suggested fragmentation pathway for (A) phenolic and (B) sulfoxidic metabolites of bupr... more Figure 6. Suggested fragmentation pathway for (A) phenolic and (B) sulfoxidic metabolites of buprofezin. (C) LC-ESI-QTOF chromatogram and (D) MS/MS spectrum (precursor ion m/z 322) from a positive buprofezin banana skin sample (0.28 mg/kg) containing the phenolic metabolite.
Analytical Chemistry, 2000
An in-depth study of SPME optimization and application has been made, considering not only aqueou... more An in-depth study of SPME optimization and application has been made, considering not only aqueous (surface water and groundwater samples) but also the more complex soil samples. Seven herbicides widely used in the area of study have been selected including five triazine herbicides (atrazine, simazine, terbumeton, terbuthylazine, terbutryn), molinate, and bromacil. Linearity range was between 0.1 and 10 ng/mL and the repeatability below 10% when applying the optimized SPME procedure to water samples. Reproducibility was found to be lower than 20% at the 1 ng/mL level, and the limits of determination in environmental water samples using GC/MS (SIM mode) were well below 0.1 ng/mL (values ranging from 10 to 60 ng/L). Extraction of selected herbicides from soil was carried out by microwave-assisted solvent extraction using methanol in screw-capped vials, leading to recoveries over 80% in spiked soil samples at the 5-200 ng/g level. SPME application over methanolic soil extracts required a 10-fold dilution with distilled water. The recommended procedure was found to be fully applicable for quantitative determination of selected herbicides in soils containing low organic matter content with coefficients of variation below or around 10% and limits of determination ranging from 1 to 10 ng/g. Both procedures were applied to real-world surface water and soil samples where several pesticides were detected including atrazine, simazine, terbuthylazine, and molinate.
Analytical and Bioanalytical Chemistry, 2010
This work describes the optimization, validation and application to real samples of an ultra-high... more This work describes the optimization, validation and application to real samples of an ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the quantification and confirmation of 11 compounds (atrazine, simazine, terbuthylazine, terbumeton, terbutryn and their main transformation products) in surface and wastewater samples. Most of these analytes are included in the list of priority substances in the framework on European Water Policy. The application of this method to water samples reveals that the most relevant transformation products (TPs) should be incorporated into current analytical methods (which are focused mainly on the determination of unchanged compounds), to obtain a more realistic knowledge on water quality regarding pesticide contamination. TPs are generally more polar and mobile than the parents and they can be transported to the aquatic environment more rapidly than their precursors. Additionally, they can present some degree of toxicity and in fact TPs are also included within the legislation on drinking water as pesticide derivatives. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyzer was used. Working in selected reaction monitoring mode, up to three simultaneous transitions per compound were acquired allowing a reliable identification at ng/L levels. The method developed includes a pre-concentration step based on solid-phase extraction (OASIS HLB cartridges). Satisfactory recoveries (70-120%) and relative standard deviations (<20%) were obtained for all compounds in different water samples types spiked at two concentration levels (0.025 and 0.1 µg/L). The optimized method was found to have excellent sensitivity with instrumental detection limits as low as 50 fg. In addition, the influences of the matrix constituents on ionization efficiency and extraction recovery have been studied in different types of Italian and Spanish surface and urban wastewater. Signal suppressions were observed for all compounds, especially for influent wastewater. The use of isotope-labelled internal standards was found to be the best approach to assure an accurate quantification in all matrix samples.
Analytical and Bioanalytical Chemistry, 2010
In order to investigate the presence of other non-target contaminants, water samples were also an... more In order to investigate the presence of other non-target contaminants, water samples were also analyzed by using GC-TOF MS and LC-QTOF MS. Several organic pollutants that did not form a part of the previous list of target contaminants were identified in the samples, thanks to the good sensitivity of TOF MS in full spectrum acquisition mode and the valuable accurate mass information provided by these instruments. The insecticide diazinon, the fungicide diphenylamide, the UV filter benzophenone, N-butyl benzenesulfonamide (N-BBSA), the insect repellent diethyltoluamide, caffeine or pharmaceuticals like erythromycin, benzenesulfonanilide, ibruprofen, atenolol or paracetamol, were some of the compounds identified in the water samples analyzed.
Analytical and Bioanalytical Chemistry, 2010
Cardiac Surgery-Associated Acute Kidney Injury: A Comparison of Two Consensus Criteria
The Annals of Thoracic Surgery, 2010
Cardiac surgery-related acute kidney injury has short- and long-term impact on patients&amp;a... more Cardiac surgery-related acute kidney injury has short- and long-term impact on patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; risk for further morbidity and mortality. Consensus statements have yielded criteria--such as the risk, injury, failure, loss, and end-stage kidney disease (RIFLE) criteria, and the Acute Kidney Injury Network (AKIN) criteria--to define the type and consequence of acute kidney injury. We sought to estimate the ability of both the RIFLE and and AKIN criteria to predict the risk of in-hospital mortality in the setting of cardiac surgery. Data were collected on 25,086 patients undergoing cardiac surgery in Northern New England from January 2001 to December 2007, excluding 339 patients on preoperative dialysis. The AKIN and RIFLE criteria were used to classify patients postoperatively, using the last preoperative and the highest postoperative serum creatinine. We compared the diagnostic properties of both criteria, and calculated the areas under the receiver operating characteristic curve. Acute kidney injury occurred in 30% of patients using the AKIN criteria and in 31% of patients using the RIFLE criteria. The areas under the receiver operating characteristic curve for in-hospital mortality estimated by AKIN and RIFLE criteria were 0.79 (95% confidence interval: 0.77 to 0.80) and 0.78 (95% confidence interval: 0.76 to 0.80), respectively (p = 0.369). The AKIN and RIFLE criteria are accurate early predictors of mortality. The high incidence of cardiac surgery postoperative acute kidney injury should prompt the use of either AKIN or RIFLE criteria to identify patients at risk and to stimulate institutional measures that target acute kidney injury as a quality improvement initiative.
The Annals of Thoracic Surgery, 2007
Background. Preliminary reports have documented the safety of off-pump coronary artery bypass gra... more Background. Preliminary reports have documented the safety of off-pump coronary artery bypass graft compared with conventional coronary artery bypass graft surgery. Whereas off-pump coronary artery bypass graft surgery may be associated with improvement in some short-term outcomes, longer-term outcomes and influence on neurocognitive function have not been fully assessed. We examined short-term and intermediate-term neurocognitive and index admission morbidity and mortality after coronary artery bypass surgery performed with and without the use of extracorporeal circulation. Methods. We prospectively randomly assigned 201 patients undergoing nonemergent isolated coronary artery bypass graft surgery to conventional coronary artery bypass graft surgery (n ؍ 102) or off-pump coronary artery bypass graft surgery (n ؍ 99). The primary end points of the study were neurocognitive function assessed using a 19-test neurocognitive battery at baseline, discharge, and 6 months. Neurocognitive deficit was defined as a 20% or greater reduction from baseline in at least 20% of the tests. Secondary end points included index admission mortality, stroke, low-output cardiac failure, return to the operating room for bleeding, and postoperative troponin release. Risk ratios and 95% confidence intervals were calculated based on intention-totreat analysis. Results. There was no difference in neurocognitive deficit at discharge (discharge versus preoperative: risk ratio, 0.83; 95% confidence interval, 0.65 to 1.07) or at 6 months (6 months versus preoperative: risk ratio, 0.94; 95% confidence interval, 0.70 to 1.28). There was no significant difference in mortality or morbidity between the two groups. The off-pump coronary artery bypass graft group had fewer patients with troponin release than the conventional coronary artery bypass graft group. Conclusions. Off-pump coronary artery bypass graft surgery did not result in decreased frequency of neurocognitive deficit. Off-pump coronary artery bypass graft surgery was associated with substantially lower levels of troponin release after surgery.
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Papers by Felix Hernandez