Impact of crop-manure ratios on energy production and fertilizing characteristics of liquid and solid digestate during codigestion.

The influence of maize silage-manure ratios on energy output and digestate characteristics was studied using batch experiments. The methane production, nutrients availability (N and P) and heavy metals' content were followed in multiflask experiments at digestion times 7, 14, 20, 30 and 60 days. In addition, the available nutrient content in the liquid and solid parts of the digestate was evaluated. Aanaerobic digestion favoured the availability of nutrients to plants, after 61 days 20-26% increase in NH4+ and 0-36% increase in PO4(3-) were found in relation to initial concentrations. Digestion time and maize addition increased the availability of PO4(3-). Inorganic nutrients were found to be mainly available in the liquid part of the digestate, i.e. 80-92% NH4+ and 65-74% PO4(3-). Manure had a positive effect on the methane production rate, whereas maize silage increased the total methane production per unit volatile solids in all treatments.

Decontamination of the digestive tract and oropharynx in ICU patients.

BACKGROUND: Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting. METHODS: We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance. RESULTS: A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively. CONCLUSIONS: In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)

Environmental consequences of processing manure to produce mineral fertilizer and bio-energy.

Liquid animal manure and its management contributes to environmental problems such as, global warming, acidification, and eutrophication. To address these environmental issues and their related costs manure processing technologies were developed. The objective here was to assess the environmental consequences of a new manure processing technology that separates manure into a solid and liquid fraction and de-waters the liquid fraction by means of reverse osmosis. This results in a liquid mineral concentrate used as mineral nitrogen and potassium fertilizer and a solid fraction used for bio-energy production or as phosphorus fertilizer. Five environmental impact categories were quantified using life cycle assessment: climate change (CC), terrestrial acidification (TA), marine eutrophication (ME), particulate matter formation (PMF), and fossil fuel depletion (FFD). For pig as well as dairy cattle manure, we compared a scenario with the processing method and a scenario with additional anaerobic digestion of the solid fraction to a reference situation applying only liquid manure. Comparisons were based on a functional unit of 1 ton liquid manure. System boundaries were set from the manure storage under the animal house to the field application of all end products. Scenarios with only manure processing increased the environmental impact for most impact categories compared to the reference: ME did not change, whereas, TA and PMF increased up to 44% as a result of NH3 and NO(x) emissions from processing and storage of solid fraction. Including digestion reduced CC by 117% for pig manure and 104% for dairy cattle manure, mainly because of substituted electricity and avoided N2O emission from storage of solid fraction. FFD decreased by 59% for pig manure and increased 19% for dairy cattle manure. TA and PMF remained higher compared to the reference. Sensitivity analysis showed that CH4 emission from manure storage, NH3 emission from processing, and the replaced nitrogen fertilizer by the mineral concentrate were important parameters affecting final results. It was concluded that processing fattening pig and dairy cattle manure to produce mineral fertilizer increased overall environmental consequences in terms of CC (except for dairy cattle manure), TA, PMF, and FFD compared to current agricultural practice. Adding the production of bio-energy reduced CC and FFD. Only when NH3 emission from processing was low and bio-energy was produced, overall equal or better environmental performance was obtained for TA and PMF. It was emphasized that real time measurements should be done to enhance the environmental assessment of manure processing technologies. Results of this study present the full environmental consequences of manure processing and key parameters affecting the environmental impact of manure management. Outcomes can be used for decision making and further tackling of environmental problems related to manure management.

[Intra uterine insemination with processed sperm for HIV serodiscordant couples in whom the man is HIV positive]. / Intra-uteriene inseminatie met bewerkt sperma bij HIV-serodiscordante paren met een HIV-positieve man.

The desire to have children is more and more common in HIV serodiscordant couples. The Academic Medical Centre Amsterdam has developed a new treatment protocol for couples in whom the man is HIV positive. Semen is processed to obtain HIV-1 free spermatozoa. These spermatozoa are used for IUI treatment. Thus far, 20 serodiscordant couples underwent 76 IUI cycles. An insemination was performed in 50 cycles (66%). The insemination was cancelled in 26 cycles, because of too many follicles (risk for multiple pregnancy), weekend (no possibilities for virological testing), not enough spermatazoa after preparation, a positive HIV-1 RNA test and other reasons. 10 out of 20 women became pregnant (50%), 8 women were on-going pregnant. The clinical and ongoing pregnancy rate per started cycle was 13% and 11% respectively. 7 babies have thus far been born and none of the mothers or babies seroconverted within this study period. Larger numbers of patients are necessary to support the safety of this program.

Immunocytochemical localization of acrosin and hyaluronidase in epididymal and ejaculated porcine spermatozoa.

Acrosin and hyaluronidase demonstrated different release patterns following treatment of living spermatozoa with the Ca2+-ionophore A 23187. One hour after the acrosomal reaction about 50% of the acrosin was still associated with the spermatozoal membranes, while hyaluronidase could no longer be detected in the spermatozoal remnants. Strong fixation conditions with acrolein and glutaraldehyde were used to prevent redistribution and leakage of these sperm proteins. Lost antigenicity was restored with sodium-borohydride and pronase E treatment. Immunofluorescent localization showed hyaluronidase to be confined to the anterior portion of the acrosome. Acrosin was localized throughout the entire acrosome including the equatorial segment. By immunoelectron microscopy, hyaluronidase was exclusively found in the acrosomal matrix. The equatorial segment was devoid of hyaluronidase. Acrosin was found in the acrosomal matrix as well as on the outer acrosomal membrane. Furthermore, labeling for acrosin in the equatorial segment was clearly demonstrated. Localization of hyaluronidase was the same for epididymal and ejaculated sperm cells but in approximately 70% of the epididymal spermatozoa acrosin could not be detected in the equatorial segment. In most of these epididymal cells acrosin was confined to the anterior part of the acrosome comparable with hyaluronidase. These observations support the motion that the appearance of acrosin in the equatorial segment is part of the maturation process during passage through the epididymis.

Absence of deleted in azoospermia (DAZ) genes in spermatozoa of infertile men with somatic DAZ deletions.

OBJECTIVE: To determine the presence or absence of the deleted in azoospermia (DAZ) gene clusters in the Y-bearing spermatozoa in semen of severely oligozoospermic men or in testicular biopsy samples of azoospermic men with somatic DAZ deletions. DESIGN: Prospective study. SETTING: Academic hospital. PATIENT(S): Nineteen patients attending our clinics for therapeutic intracytoplasmic injection of sperm. INTERVENTION(S): Peripheral blood lymphocytes were used to obtain somatic DNA for analysis using the polymerase chain reaction. Analysis of chromosomes X and Y and the detection of the DAZ gene clusters were carried out with the fluorescence in situ hybridization technique in spermatozoa remaining after intracytoplasmic sperm injection. MAIN OUTCOME MEASURE(S): Presence or absence of the DAZ gene clusters in matched somatic DNA and Y-bearing spermatozoa. RESULT(S): Seven patients appeared to have a somatic DAZ deletion. Three-color fluorescence in situ hybridization showed that all Y-bearing spermatozoa examined from these men carried the same deletion. CONCLUSION(S): The DAZ deletions present in the seven men would all have been transmitted if they had fathered sons through artificial fertilization techniques using the sperm cells examined in this study.

The development of spectral EEG changes during short periods of circulatory arrest.

The EEG was monitored in 56 patients during implantation of an internal cardioverter defibrillator. The purpose of this study was to determine the main EEG frequency ranges that represent ischemic changes during short periods of circulatory arrest. The EEG was recorded with a 16-channel common reference montage (Cz). After onset of circulatory arrest, the log spectral changes of three-epoch moving averages were calculated relative to the baseline spectrum. For factor analysis, 17 EEG periods were selected that showed changes progressing to an isoelectrical period. Topographic differences and the time course of quantitative EEG (qEEG) changes were studied in all 56 patients. For each patient the EEG period with the longest duration of circulatory arrest was chosen. Factor analysis revealed four factors that represented the spectral EEG changes occurring during circulatory arrest and recovery. The frequency intervals of these factors were 0 to 0.5 Hz, 1.5 to 3 Hz, 7.5 to 9.5 Hz, and 15 to 20 Hz for all channels. Only minor topographic differences were found in the power of the spectral changes; the sequence of events was similar for all electrode positions. The first EEG change after circulatory arrest was an initial increase in alpha power and a decrease in beta power. On average, after approximately 15 seconds alpha power started to decrease, beta power decreased further, delta-1 power started to increase, and delta-2 power started to decrease. After approximately 25 seconds, the delta-1 power increase appeared to plateau or to decrease. A circulatory arrest longer than approximately 30 seconds resulted in an isoelectrical EEG. After restoration of the circulation, there was a fast transient increase in delta-1 and delta-2 power, followed by a decrease to baseline. alpha and beta power showed a more gradual increase in power toward baseline and were the last to restore after 60 to 90 seconds. In general, the spectral changes in the alpha and beta frequency ranges were most pronounced and consistent. In conclusion, to detect intraoperative cerebral ischemia, monitoring of changes in the four frequency ranges found is preferable to monitoring changes in the classically defined frequency bands. Furthermore, these results stress the importance of the alpha and beta ranges in detecting cerebral ischemia.

Biventricular pacing in end-stage heart failure improves functional capacity and left ventricular function.

BACKGROUND: Asynchronous patterns of contraction and relaxation may contribute to hemodynamic and functional impairment in heart failure. In 1993, we introduced biventricular pacing as a novel method to treat heart failure by synchronous stimulation of the right and left ventricles after an appropriate atrioventricular delay. The objectives of this study were to assess the early and long-term effects of this therapy on functional capacity and left ventricular function in patients with severe heart failure and left bundle branch block. METHODS AND RESULTS: Twelve patients with end-stage congestive heart failure, sinus rhythm and complete left bundle branch block were treated with biventricular stimulation at optimized atrioventricular delay. The NYHA functional class and maximal bicycle exercise capacity were assessed. Systolic and diastolic left ventricular function were studied with echocardiography and radionuclide angiography. Data was collected at various intervals during 1-year follow-up. Cumulative survival [95% CI] was 66.7% [40.0,93.4] at 1 year and 50 % [21.8, 78.2] at 2 and 3 years. Median NYHA class improved from class IV to class II at 1 year (p=0.008). After 6 weeks an increase in exercise capacity occurred, which was sustained. A less restrictive left ventricular filling pattern, an increase in dP/dt and left ventricular ejection fraction, and a decrease in mitral regurgitation were observed early and long-term. CONCLUSIONS: Biventricular pacing at optimized atrioventricular delay results in improvement in functional capacity, which is associated with improved systolic and diastolic left ventricular function, and a decrease in mitral regurgitation during short- and long-term follow-up.

[HIV and reproductive choices]. / HIV en reproduktieve keuzen.

PIP: It is estimated that there are about 120-150 hemophilic men infected with HIV in the Netherlands as well as 1000 men infected via intravenous drug use. The majority of them are in reproductive age with relationships with seronegative women. In the event they want to have a child, artificial insemination with donor sperm (KID) is an option. In 1994 there were 147 instances of insemination of 66 women with the processed semen of HIV-positive men and no infection resulted. The annual risk of HIV infection was 7.2% of a woman engaging in unprotected intercourse, according to a prospective Italian study. The risk of HIV infection per contact was estimated at 0.1-5.6%. However, it is not yet proven that processed sperm of an HIV-seropositive man can produce a pregnancy without the risk of infecting the woman. The risk of transmission of HIV to the fetus is higher in artificial insemination of a seropositive woman with the sperm of her partner. In vitro fertilization is not a sure method either for the prevention of HIV infection of the mother because of the possibility of an egg cell being infected before fertilization. HIV-infected pregnant women face the problems of caring for HIV-infected offspring. For HIV discordant couples the advice is to use both condoms for the prevention of infection and oral contraceptives for the prevention of pregnancy. In the case of a lesbian relationship, if the partners want to have a child, HIV infection is still a factor because of previous heterosexual contacts.^ieng

[Preimplantation genetic screening for numerical chromosomal abnormalities in embryos from women of 35 years of age and older; first results in The Netherlands]. / Preïmplantatiegenetische screening op numerieke chromosoomafwijkingen bij embryo's van vrouwen van 35 jaar en ouder; de eerste resultaten in Nederland.

OBJECTIVE: To assess the results of preimplantation genetic screening (PGS) for numerical chromosomal abnormalities in embryos from women of 35 years of age and older. DESIGN: Prospective, descriptive. METHOD: Women who were at least 35 years received standard IVF/ICSI treatment including ovarian hyperstimulation, after which matured oocytes were recovered and inseminated. Three days after insemination, one cell was biopsied from each of the available embryos. In these cells, the copy number of 5 (first 21 patients) or 8 chromosomes was determined using fluorescence in situ hybridisation (FISH). Only embryos with a normal or unknown FISH result were implanted in the uterus. Data were collected in an electronic database. RESULTS: PGS was done for 28 IVF- and 22 ICSI-treatments; the average age of the 50 women at the beginning of treatment was 38.5 years. There were 360 embryos generated; of the 288 biopsied embryos 156 (54%) contained an abnormal number of chromosomes. In 45 women, 1 or 2 embryos were transferred. This resulted in 8 ongoing pregnancies (8/50; 16%) and the birth of 9 children, all of whom were found to be healthy on a paediatric examination at 3 to 10 months of age. In 4 cases there was no embryo transfer because all the embryos were chromosomally abnormal. CONCLUSION: In the first 50 patients in The Netherlands, PGS resulted in an ongoing pregnancy rate of 16% per woman. All children showed normal growth and development.

Properties of amphiphilic oligonucleotide films at the air/water interface and after film transfer.

The self-assembly of amphiphilic hybrid materials containing an oligonucleotide sequence at the air/water interface was investigated by means of pressure-molecular area (Π-A) isotherms. In addition, films were transferred onto solid substrates and imaged using scanning force microscopy. We used oligonucleotide molecules with lipid tails, which consisted of a single stranded oligonucleotide 11 mer containing two hydrophobically modified 5-(dodec-1-ynyl)uracil nucleobases (dU11) at the 5'-end of the oligonucleotide sequence. The air/water interface was used as confinement for the self-assembling process of dU11. Scanning force microscopy of films transferred via Langmuir-Blodgett technique revealed mono-, bi- (Π ≥ 2 mN/m) and multilayer formation (Π ≥ 30 mN/m). The first layer was 1.6 ± 0.1 nm thick. It was oriented with the hydrophilic oligonucleotide moiety facing the hydrophilic substrate while the hydrophobic alkyl chains faced air. In the second layer the oligonucleotide moiety was found to face the air. The second layer was found to cover up to 95% of the sample area. Our measurements indicated that the rearrangement of the molecules into bi- and multiple bilayers happened already at the air/water interface. Similar results were obtained with a second type of oligonucleotide amphiphile, an oligonucleotide block copolymer, which was composed of an oligonucleotide 11 mer covalently attached at the terminus to polypropyleneoxide (PPO).

Comparing environmental consequences of anaerobic mono- and co-digestion of pig manure to produce bio-energy--a life cycle perspective.

The aim of this work was to assess the environmental consequences of anaerobic mono- and co-digestion of pig manure to produce bio-energy, from a life cycle perspective. This included assessing environmental impacts and land use change emissions (LUC) required to replace used co-substrates for anaerobic digestion. Environmental impact categories considered were climate change, terrestrial acidification, marine and freshwater eutrophication, particulate matter formation, land use, and fossil fuel depletion. Six scenarios were evaluated: mono-digestion of manure, co-digestion with: maize silage, maize silage and glycerin, beet tails, wheat yeast concentrate (WYC), and roadside grass. Mono-digestion reduced most impacts, but represented a limited source for bio-energy. Co-digestion with maize silage, beet tails, and WYC (competing with animal feed), and glycerin increased bio-energy production (up to 568%), but at expense of increasing climate change (through LUC), marine eutrophication, and land use. Co-digestion with wastes or residues like roadside grass gave the best environmental performance.

Rectal microcirculatory alterations after elective on-pump cardiac surgery.

BACKGROUND: Hemodynamic changes, related to on-pump cardiac surgery, have been reported to impair intestinal perfusion. However, until recently, direct in vivo observation of the intestinal microcirculation was not clinically feasible, and the concept of altered intestinal blood flow in the setting of cardiac surgery depended on indirect observations from other techniques, such as tonometry and microdialysis. To establish the incidence of intestinal microvascular alterations after cardiac surgery, we performed direct in vivo observation of the microcirculation in a clinically accessible part of the intestinal tract in this setting. METHODS: A single-center prospective observational study was conducted in postoperative elective on-pump cardiac surgery patients. Simultaneously, sidestream dark field (SDF) imaging and automated gas tonometry were performed in the rectal pouch within 30 minutes after ICU admission. RESULTS: The rectal median microvascular flow index was 3(3-3) and the proportion of perfused vessels (PPV) was 85% (72-93). The median rectal-to-arterial partial carbon dioxide pressure difference (ΔPCO(2)) was 1.5 (-1.5-8.3) mmHg; 6 (21%) patients had a ΔPCO(2)> 8.3 mmHg, among them 2 (7%) with values> 10.5 mmHg. CONCLUSION: After elective on-pump cardiac surgery, direct in vivo observation of rectal mucosa revealed a PPV <90% in 54% of all patients. At the same time, rectal microcirculatory blood flow appeared to be unaltered. Combining rectal SDF imaging with rectal tonometry revealed a 7% incidence of rectal-to-arterial pCO(2) gap >1.4,kPa, suggesting non-dysoxic perfusion in the majority of patients, despite the observed percentage of non-perfused crypts.

Bioconcentration kinetics of the organophosphorus insecticide chlorpyrifos in guppies (Poecilia reticulata).

The bioconcentration kinetics of chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) in guppies (Poecilia reticulata) were investigated. A static exposure was used to study the uptake of the compound. The amount absorbed was calculated from the difference in disappearance rates from the water phase in aquaria with and without fish. The uptake rate was found to be first-order with respect to the exposure concentration, and amounts to ca. 38 ml g-1 (fish) hr-1. The elimination rate was studied in separate experiments. Guppies were first given the opportunity to accumulate chlorpyrifos and, following transfer to clean water, the clearance of the compound was measured by determining the residual chlorpyrifos in the fish. It was found that the elimination rate was first-order with respect to the concentration in fish, but depended slightly on the length of the preexposure period. The half-life of tissue chlorpyrifos varied from 31 to 38 hr. Release of unchanged chlorpyrifos turned out to be negligible relative to the amount eliminated. This indicates that metabolic breakdown is the only pathway for elimination. From the kinetic rate parameters, a bioconcentration factor was calculated of about 1700. This value is very similar to that measured directly after an 8-day semistatic exposure. A two-compartment model is proposed to describe the kinetics of the bioconcentration process. The conditions limiting the applicability of the indirect method for measuring the toxicokinetics of chlorpyrifos are discussed.

Capnography does not reliably detect double-lumen endotracheal tube malplacement.

Two patients are described in whom double-lumen endotracheal tube malplacement and its ventilatory consequences were not detected by infrared capnography. Problems were suspected on auscultation, and the malplacement was diagnosed by means of bronchospirometry. We conclude that bronchospirometry helps detect problems with endotracheal intubation.

Neurophysiological effects of pediatric balloon dilatation procedures.

Balloon dilatation of valvar and vascular stenoses has become routine therapy in pediatric cardiology. Repeated balloon inflations cause many episodes of low cerebral oxygen delivery. This study is a prospective study to assess the effects of balloon dilatation on cerebral perfusion and oxygenation. The study included 11 patients scheduled for elective catheterization and balloon dilatation at a university pediatric hospital. Blood flow velocity in the middle cerebral artery (Vmca) and regional cerebral oxygen saturation (rSO2) were monitored by means of transcranial Doppler sonography and near infrared spectroscopy, respectively. In group 1, consisting of 6 patients without an intracardiac shunt, inflation of the balloon resulted in a decrease in Vmca followed by a minor decrease in rSO2. In group 2, consisting of 5 patients with an interatrial communication, inflation resulted in an increase in right-to-left shunt fraction, arterial desaturation. and a major decrease in rSO2 with minor changes in Vmca. Balloon dilatation causes an important decrease in cerebral oxygen delivery by different mechanisms. This may lead to serious morbidity and even mortality. Neuromonitoring is a useful tool in assessing the cerebral effects of balloon dilatation and brain recovery.

Infusion of vecuronium controlled by a closed-loop system.

Closed-loop control of neuromuscular blockade, using a semi-continuous infusion of vecuronium, is described. In 28 patients, the average neuromuscular transmission was between 13 and 17% of control. Requirements for vecuronium averaged 1.1 micrograms kg-1 min-1 (0.8-1.5 micrograms kg-1 min-1), being in the same range as for repeated bolus injections. No side effects were observed. After the infusion was stopped recovery was rapid. Only three patients required induced reversal of blockade.

A randomized trial between GIFT and ovarian stimulation for the treatment of unexplained infertility and failed artificial insemination by donor.

This study was designed to investigate the surplus effect of gamete intra-Fallopian transfer (GIFT) over ovarian stimulation alone, in patients with unexplained infertility. A total of 50 patients with unexplained infertility of at least 3 years duration, or unexplained failure of artificial insemination by donor (AID) for at least 12 cycles, meeting strict inclusion criteria, were randomly selected for either two GIFT cycles or two ovarian stimulation cycles. Ovarian stimulation was combined with timed intercourse, or timed cervical donor insemination. In 38 completed GIFT cycles, five clinical pregnancies (13.2% per cycle) occurred and in 44 ovarian stimulation cycles four clinical pregnancies occurred (9.1% per cycle). Five remaining GIFT cycles were converted into in-vitro fertilization leading to two pregnancies. Of the 50 patients suffering from unexplained infertility, the 23 who did not have AID gave rise to four pregnancies out of 39 cycles (10.3%); from the remaining 27 patients who underwent AID, seven pregnancies were achieved out of 48 cycles (14.6%). No statistical differences between GIFT and ovarian stimulation treatment were found. Therefore, the GIFT success rates can be explained at least in part, if not fully, by the effect of ovarian stimulation alone. Consequently, ovarian stimulation should be considered in unexplained infertility before more elaborate forms of assisted reproduction are used.

Neuromonitoring in defibrillation threshold testing. A comparison between EEG, near-infrared spectroscopy and jugular bulb oximetry.

OBJECTIVES: The aim was to study the physiological effects of induced ventricular fibrillation and subsequent circulatory arrest for defibrillation threshold testing on the brain using the EEG, jugular bulb oxymetry and near-infrared spectroscopy. METHODS: Thirteen patients undergoing surgery for implantable cardioverter-defibrillator implantation or replacement under general anesthesia were included. We continuously monitored the jugular bulb oxygen saturation (SjO2), regional oxygen saturation (rSO2) and the EEG. RESULTS: 59 episodes of circulatory arrest were studied. In all cases the rSO2 fell instantly while the EEG changed within 12 +/- 4 seconds after induction. The EEG indicated ischemic changes, ranging from occurrence of rhythmic delta activity to cessation of all electrical activity. On successful defibrillation the rSO2 increased to values in excess of pre-arrest levels and restored towards baseline; the SjO2 initially fell followed by a similar overshoot. Recovery times increased in proportion to arrest duration. CONCLUSION: Short lasting episodes of circulatory arrest have serious, but transient effects on brain function. The rSO2 is an effective non-invasive tool for monitoring cerebral oxygenation during DFT-testing.