[Framework for responsible venous access and IV management]. / Allen op één lijn ? Kaders voor verantwoorde veneuze toegang en infuusmanagement.

Intravascular catheters are indispensable in current healthcare. The introduction of a peripheral venous or central venous catheter and managing infusion therapy are care processes that over time have become integral to the organisation, and in which multiple care providers play a role. Introducing an IV appears to be a straightforward repetitive task, but often proves to be a considerable burden to the patient and a source of dissatisfaction, morbidity and mortality. Inadequate decision-making, inexperience and lack of a guideline can lead to poor IV management. There is a need for improvement in many care facilities. A programmatic approach such as the Vessel Health and Preservation Principle can be a great asset in this. In this article we outline the framework for responsible vascular access and infusion therapy.

Logistic analysis of algae cultivation.

Energy requirements for resource transport of algae cultivation are unknown. This work describes the quantitative analysis of energy requirements for water and CO2 transport. Algae cultivation models were combined with the quantitative logistic decision model 'BeWhere' for the regions Benelux (Northwest Europe), southern France and Sahara. For photobioreactors, the energy consumed for transport of water and CO2 turns out to be a small percentage of the energy contained in the algae biomass (0.1-3.6%). For raceway ponds the share for transport is higher (0.7-38.5%). The energy consumption for transport is the lowest in the Benelux due to good availability of both water and CO2. Analysing transport logistics is still important, despite the low energy consumption for transport. The results demonstrate that resource requirements, resource distribution and availability and transport networks have a profound effect on the location choices for algae cultivation.

Intermittent warm blood versus cold crystalloid cardioplegia for myocardial protection: a propensity score-matched analysis of 12-year single-center experience.

OBJECTIVES: This study analyzes the efficacy in myocardial protection of two types of cardioplegia solutions, namely, blood and crystalloid cardioplegia, both given intermittently in patients undergoing coronary artery bypass grafting (CABG). METHODS: Adult patients undergoing primary isolated coronary artery bypass grafting between January 1998 and January 2011 with cardiopulmonary bypass, using either blood or crystalloid cardioplegia, were identified in our database. Propensity score matching was performed to create comparable patient groups. Multivariate logistic regression analysis was performed to identify independent risk factors for perioperative myocardial damage. The primary endpoint of the study was the maximum creatine kinase-MB (CK-MB) value within 5 days postoperatively with a cut-off point of 100 U/L. Early mortality and perioperative low cardiac output syndrome in both groups were compared. RESULTS: The study included 7138 CABG patients: 3369 patients using crystalloid cardioplegia and 3769 using blood cardioplegia. After propensity score matching, 2585 patients per study group remained for the analysis. Wilcoxon signed-rank test revealed significantly higher CK-MB levels in patients operated with the use of blood cardioplegia. Multivariate regression analysis identified blood cardioplegia as an independent risk factor for elevated CK-MB levels. However, it was associated with lower aspartate aminotransferase (AST) levels. The type of cardioplegia had no influence on early mortality, postoperative low cardiac output syndrome or intensive care unit stay. CONCLUSIONS: Blood cardioplegia was identified as an independent risk factor for elevated levels of CK-MB after CABG, but was associated with lower AST levels. The authors conclude that the type of cardioplegia had no significant influence on clinical outcome.

Evidence-based consensus on the insertion of central venous access devices: definition of minimal requirements for training.

There is a lack of standard minimal requirements for the training of insertion techniques and maintenance of central venous access devices (CVADs). An international evidence-based consensus task force was established through the World Congress of Vascular Access (WoCoVA) to provide definitions and recommendations for training and insertion of CVADs. Medical literature published from February 1971 to April 2012 regarding 'central vascular access', 'training', 'competency', 'simulation', and 'ultrasound' was reviewed on Pubmed, BioMed Central, ScienceDirect, and Scopus databases. The GRADE and the GRADE-RAND methods were utilized to develop recommendations. Out of 156 papers initially identified, 83 papers described training for central vascular access placement. Sixteen recommendations are proposed by this task force, each with an evidence level, degree of consensus, and recommendation grade. These recommendations suggest central venous access education include didactic or web-based teaching with insertion procedure, infection prevention, complications, care, and maintenance of devices, along with laboratory models and tools for simulation practice incorporating ultrasound. Clinical competence should be determined by observation during clinical practice using a global rating scale rather than by the number of procedures performed. Ensuring safe insertion and management of central venous devices requires standardized education, simulation practice, and supervised insertions.

Darcian permeability constant as indicator for shear stresses in regular scaffold systems for tissue engineering.

The shear stresses in printed scaffold systems for tissue engineering depend on the flow properties and void volume in the scaffold. In this work, computational fluid dynamics (CFD) is used to simulate flow fields within porous scaffolds used for cell growth. From these models the shear stresses acting on the scaffold fibres are calculated. The results led to the conclusion that the Darcian (k(1)) permeability constant is a good predictor for the shear stresses in scaffold systems for tissue engineering. This permeability constant is easy to calculate from the distance between and thickness of the fibres used in a 3D printed scaffold. As a consequence computational effort and specialists for CFD can be circumvented by using this permeability constant to predict the shear stresses. If the permeability constant is below a critical value, cell growth within the specific scaffold design may cause a significant increase in shear stress. Such a design should therefore be avoided when the shear stress experienced by the cells should remain in the same order of magnitude.

Constant specific growth rate in fed-batch cultivation of Bordetella pertussis using adaptive control.

Monitoring and control of production processes for biopharmaceuticals have become standard requirements to support consistency and quality. In this paper, a constant specific growth rate in fed-batch cultivation of Bordetella pertussis is achieved by a newly designed specific growth rate controller. The performance of standard control methods is limited because of the time-varying characteristics due to the exponentially increasing biomass and volume. To cope with the changing dynamics, a stable model reference adaptive controller is designed which adapts the controller settings as volume and biomass increase. An important asset of the design is that dissolved oxygen is the only required online measurement. An original design without considering the dissolved oxygen dynamics resulted experimentally in oscillatory behaviour. Hence, in contrast to common believes, it is essential to include dissolved oxygen dynamics. The robustness of this novel design was tested in simulation. The validity of the design was confirmed by laboratory experiments for small-scale production of B. pertussis. The controller was able to regulate the specific growth rate at the desired set point, even during a long fed-batch cultivation time with exponentially increasing demands for substrates and oxygen.

Tissue- and time-dependent estrogen receptor activation in estrogen reporter mice.

With the aim of developing an in vivo model that directly detects activation of estrogen receptors (ERs), transgenic mice carrying a luciferase reporter gene were generated. The luciferase reporter gene was under the control of three consensus estrogen-responsive elements (EREs) coupled to a minimal TATA-box, with or without flanking chick beta-globin insulators. By using this model in combination with the IVIS imaging system, in vivo ER activation was measured. Dose- and time-dependent luciferase activity was induced in various organs of adult transgenic male mice exposed to diethylstilbestrol (DES) (10-1000 micro g/kg) and 17beta-estradiol dipropionate (EP) (10-1000 micro g/kg), when luciferase activity was measured ex vivo. The highest (>10 000-fold) induction of luciferase was measured in bone and kidney 24 h after exposure to 1000 micro g/kg EP. Other highly responsive organs include liver, testis, pituitary, brain, prostate and colon, which show different activity profiles. This in vivo model for detecting estrogenic activity can be used to assess tissue-specific action of ER agonists and antagonists. These could include selective ER modulators and environmental estrogens. In combination with the IVIS imaging system, this in vivo model is a powerful tool for assessing the kinetics of gene activation by estrogenic compounds.

Pericranial muscular, respiratory, and heart rate components of the orienting response.

We have earlier found that voluntary attention to weak auditory stimuli induces inhibition of respiration, heart rate, and electromyographic (EMG) activity of masticatory and lower facial muscles and that these responses lower the auditory threshold for low-frequency sounds. In the current study, we examined whether this inhibitory response pattern also occurs during involuntary orienting to novel, nonsignal sounds. Environmental sounds of low intensity were presented unexpectedly during the performance of a reading task. Orienting responses (ORs) were elicited as indicated by heart rate deceleration and skin conductance responses. Inhibitory respiratory and pericranial EMG responses appeared to be intrinsic components of the OR. Together with the autonomic responses, they habituated when a nonsignal auditory stimulus was repeatedly presented. Our results also suggest that eye and pinna movements occurred toward the sound source. The results of the current study are consistent with the hypothesis of Sokolov (1963) that the primary function of the OR is enhancement of sensory sensitivity.

Estimation of steady-state culture characteristics during acceleration-stats with yeasts.

Steady-state culture characteristics are usually determined in chemostat cultivations, which are very time-consuming. In contrast, acceleration-stat (A-stat) cultivations in which the dilution rate is continuously changed with a constant acceleration rate are not so time-consuming, especially at high acceleration rates. Therefore, the A-stat could be advantageous to use instead of the chemostat. However, the highest acceleration rate, meaning the fastest A-stat that can be applied for estimating steady-state culture characteristics, is not known yet. Experimental results obtained with Zygosaccharomyces rouxii, an important yeast in soy sauce processes, showed that the culture characteristics during the A-stat with an acceleration rate of 0.001 h(-2) were roughly comparable to those of the chemostat. For higher acceleration rates the deviation between the culture characteristics in the A-stat and those in the chemostat obtained at the same dilution rate generally started to increase. The source of these deviations was examined by simulation for Saccharomyces cerevisiae. The simulations demonstrated that this deviation was not only dependent on the metabolic adaptation rate of the yeast, but also on the rate of change in environmental substrate concentrations during A-stats. From this work, it was concluded that an A-stat with an acceleration rate of 0.001 h(-2) is attractive to be used instead of chemostat whenever a rough estimation of steady-state culture characteristics is acceptable.

Differences in autonomic physiological responses between good and poor inductive reasoners.

We investigated individual- and task-related differences in autonomic physiological responses induced by time limited figural and verbal inductive reasoning tasks. In a group of 52 participants, the percentage of correctly responded task items was evaluated together with nine different autonomic physiological response measures and respiration rate (RR). Weighted multidimensional scaling analyses of the physiological responses revealed three underlying dimensions, primarily characterized by RR, parasympathetic, and sympathetic activity. RR and sympathetic activity appeared to be relatively more important response dimensions for poor reasoners, whereas parasympathetic responsivity was relatively more important for good reasoners. These results suggest that poor reasoners showed higher levels of cognitive processing intensity than good reasoners. Furthermore, for the good reasoners, the dimension of sympathetic activity was relatively more important during the figural than during the verbal reasoning task, which was explained in terms of hemispheric lateralization in autonomic function.

Inhibition of pericranial muscle activity, respiration, and heart rate enhances auditory sensitivity.

We investigated whether previously observed inhibition of pericranial electromyographic (EMG) activity, respiration, and heart rate during sensory intake processes improves auditory sensitivity. Participants had to detect weak auditory stimuli. We found that EMG activity in masticatory and lower facial muscles, respiration, and heart rate were more strongly inhibited when stimulus intensity was gradually lowered to threshold level whereas EMG of upper facial muscles progressively increased. Detection of near-threshold stimuli was inversely related to prestimulus EMG levels in masticatory and lower facial muscles. In two additional experiments, it was investigated whether steady, voluntary contractions negatively influence auditory sensitivity. As expected, contraction of zygomaticus produced an increase in auditory threshold in comparison with contraction of corrugator or first dorsal interosseus. It is concluded that attention to external stimuli is accompanied by quieting of those somatic activities that produce internal noise or are accompanied by impaired middle ear transmission of auditory stimuli.

Optimal signal bandwidth for the recording of surface EMG activity of facial, jaw, oral, and neck muscles.

Spontaneous pericranial electromyographic (EMG) activity is generally small and is contaminated by strong low-frequency artifacts. High-pass filtering should suppress artifacts but affect EMG signal power only minimally. In 24 subjects who performed a warned simple reaction time task, the optimal high-pass cut-off frequency was examined for nine different pericranial muscles. From four experimental conditions (visual and auditory reaction signals combined with hand and foot responses), 1-min EMG recordings were selected (bandwidth: 0.4-512 Hz) and divided into 60 1-s data segments. These segments were high-pass filtered, the -3-dB cut-off frequency varying from 5 to 90 Hz, and subjected to power spectral analysis. Optimal high-pass filter frequencies were determined for the mean power spectra based on visual estimation or comparison with a theoretical spectrum of the artifact-free EMG signal. The optimal frequencies for the different muscles varied between 15 and 25 Hz and were not influenced by stimulus or response modality. For all muscles, a low-pass filter frequency between 400 and 500 Hz was appropriate.

Totally implantable venous access devices: evaluation of complications and a prospective comparative study of two different port systems.

BACKGROUND: Totally implantable venous access devices (TIVADs) are valuable instruments in case prolonged intravenous therapy is required, but implantation and use of these devices are associated with complications. The purpose of this study was to evaluate perioperative and long-term complications associated with TIVADs. In addition, we compared two different types of TIVADs with respect to implantation, care protocol and patients' comfort. METHODS: In a retrospective study perioperative and long-term complications in a general oncology population were analysed. In a prospective randomized study comparison of two types of TIVADs was carried out. RESULTS: Perioperative complications occurred in 27 (21.4%) of 126 implanted TIVADs: catheter malposition (16.7%) in 21 patients, pneumothorax (0.8%) in one and haemorrhage (4.0%) in five. Long-term complications appeared in 31 (25.2%) out of 123 TIVADs: thrombosis in 9 (7.3%), especially associated with malposition of the tip of the catheter; infection in 10 (8.1%); extravasation in 2 (1.6%); migration of the catheter tip in 6 (4.8%); pain at reservoir in 3 (2.4%) and inaccessibility of the port in 1 (0.8%). No significant differences were found with respect to implantation, care accessibility and patients' comfort between the two TIVADs. CONCLUSIONS: The use of TIVADs is associated with some risk of serious perioperative and long-term complications. In case of thrombotic complications these systems can be saved with appropriate treatment. Correct positioning of the catheter tip is essential to prevent thrombotic complications. In case of TIVAD-related infectious complications, the possibility of saving the TIVAD depends on the causative microorganism and type of infection. Furthermore, to increase patients' satisfaction with TIVADs they should be well informed about the surgical procedure and possible disadvantages of these devices.

Estimation of the respiration quotient in a bicarbonate buffered batch cell cultivation.

In bicarbonate buffered media the carbon dioxide balance is affected by accumulation and therefore the RQ can not directly be calculated from gas flow and gas concentration measurements. To cope with the buffering capacity of such media a Kalman Filter was designed as a software sensor to estimate the RQ. To eliminate the role of a priori knowledge of cell and medium kinetics on the performance of the Kalman Filter all carbonate was lumped to one term. As a result only physical constants are required. A reference experiment verified the performance of the software sensor. Subsequently several experiments were performed with insect cells to show the progress of the RQ-values during cultivation.

Assessment of the quality of life of patients with advanced and end-stage cancer or serious infections with a symptom-based or an impact-based instrument.

In 1992 a project was started in which home care technology was made available to patients with cancer or serious infections. Primary care providers were trained and supported to administer parenteral drugs and fluids in the home setting. Between 1992 and 1995 we applied the Rotterdam Symptom Checklist (RSCL) and the Sickness Impact Profile (SIP) as questionnaires for quality of life (QoL) assessment in a group of 112 hospitalized patients who were prepared to receive further treatment at home. Scores on the RSCL revealed a high level of symptomatology in both the physical and the psychological dimension. Factor analysis showed a five-factor rather than a two-factor structure. The SIP showed considerable restrictions in daily living, particularly in the physical dimension. Whereas the RSCL and the SIP correlated well in the psychological and physical dimensions in advanced cancer patients, this correlation disappeared in the group of endstage cancer patients. The data indicate that the health-related QoL of end-stage cancer patients cannot be reliably be assessed with a symptom-based instrument alone; it needs to be supplemented by other instruments, such as the SIP.

Optimal EMG signal bandwidth and interelectrode distance for the recording of acoustic, electrocutaneous, and photic blink reflexes.

The bandwidth for the recording of the orbicularis oculi blink reflex electromyogram (EMG) response is optimal when low-frequency artifacts, such as motion artifacts and cross-talk from other muscles, are maximally suppressed, whereas true EMG signal power is maximally retained. The optimal bandwidth was investigated for acoustic, electrocutaneous, and photic blink reflexes. Reflexes were recorded with varying bandwidth and interelectrode distances of 12 and 36 mm. Power spectra of the EMG signals were calculated and compared with a theoretical spectrum of the uncontaminated EMG signal. For both electrode distances, the optimal bandwidth was on the average 28-500 Hz for acoustic and electrocutaneous blink reflexes and 12-500 Hz for photic blinks. Using photic stimuli, however, a high-pass filter frequency larger than 12 Hz (probably at least 30 Hz) in combination with occlusion of the eye will be necessary to avoid influences of retinal potentials. Given the optimal bandwidth, a larger electrode spacing may be expected to moderately improve the detectability of small blinks in all stimulus conditions.

Anticipatory EMG responses of pericranial muscles in relation to heart rate during a warned simple reaction time task.

Obrist's cardiac-somatic coupling hypothesis predicts a widespread inhibition of heart rate and task-irrelevant muscle activity during expectancy situations. This hypothesis was tested by measuring heart rate and pericranial electromyographic (EMG) activity during a warned simple reaction time task with visual or auditory reaction signals and hand or foot responses. In each of three groups of 24 participants, EMG activity of three different facial, masticatory, or neck muscles was recorded. During the warning interval preceding the presentation of the reaction signal, masticatory and lower facial muscles predominantly showed a gradual inhibition in activity concomitant with heart rate deceleration. In contrast, two upper facial muscles showed increasing activity. Pericranial EMG responses were little affected by reaction signal modality and were independent of responding limb. Greater heart rate deceleration was associated with greater inhibition and weaker facilitation of EMG responses. The results suggest a functional role of inhibitory EMG responses in increasing the perceptual sensitivity to expected signals.

Feeding of lactic acid-fermented high nutrient density weaning formula in paediatric settings in Ghana and Nigeria: acceptance by mother and infant and performance during recovery from acute diarrhoea.

A period of acute diarrhoea in infants is often associated with anorexia and weight loss. Catch-up growth is, therefore, necessary and this depends very much on the type of food, in terms of nutrient density, protein quality and digestibility, given to the child. Fermented (F) and non-fermented (NF) maize-soybean porridges of increased nutrient density were formulated and compared with traditionally fermented maize-only porridge (P) for acceptability using mothers in peri-urban Ghana as well as urban Nigeria as subjects. Subsequently, infants hospitalised in paediatric wards for acute diarrhoea, from the same communities in both countries, were assigned randomly to one or other of the three porridges. Infant subjects in all cases fell within the ages of 6-15 months. Complementary to regular breast-feeding, infants could consume as much porridge as they wanted and their total daily consumption was interpreted as an indication of acceptance. Although mothers in both the environments of Ghana and Nigeria rated P as more acceptable than F and NF, no significant difference was recorded in the quantitative intake by infants of the three formula groups. By adding enzyme-rich cereal malt flour (at the 1-5% level by weight) as a viscosity-thinning agent to F and NF porridges, it was possible to feed these porridges to infants at total solids concentration levels of 20-25% (wet basis) which is approximately double the solid matter content of the P porridge. Consequently, the daily nutrient intake by infants consuming F and NF porridges was considerably higher compared to the P porridge group. It is concluded that the concept of high nutrient density weaning foods is a feasible vehicle for an improvement of nutrient supply to infants.