Analysis of dynamic systems with DAP4H computer program

Dynamic Analysis Program, FORTRAN 4 Level H /DAP4H/, developed from 27 subprograms, features liberal use of the subroutines, subprograms, and skeletonization to minimize programming effort in formulating models of new systems and components. It formulates mathematical models of complex mechanical, pneumatic, and hydraulic dynamic systems

Smoking Cessation Interventions for COPD: A Review of the Literature

The aim of this systematic review is to establish the most effective stop smoking intervention approach for smokers with COPD. The search strategy included the electronic databases MEDLINE, EMBASE, AMED, PsycINFO, DARE, Cochrane Library, and CINAHL, between January 2006 and January 2010. References of the included studies were also screened for additional papers, and further hand searches were conducted. The selection criteria included randomized controlled trials or quasi-randomized controlled trials with at least one subject group diagnosed with COPD. Two independent reviewers reviewed the included studies, using a quality assessment form developed from the selection criteria. Divergence of quality assessment scores was resolved by the 2 reviewers agreeing on a score. The 4 studies selected indicate that psychosocial interventions combined with pharmacotherapy are effective in smoking cessation at 12 months post-intervention, although the effect is not statistically significant, due to small sample size and heterogeneity between the studies (odds ratio 2.35, 95% CI 0.25–21.74,). However, despite this medium effect size, due to a lack of universal use of pharmacotherapies in most of the studies, it makes a definitive comparison of efficacy difficult to determine. This review also shows the effectiveness of psychosocial treatment for people with or without COPD symptoms at 12 months, although the effect of disease severity is not clear. This review also highlights the difficulty of maintaining attendance at community-based locations, compared to acute or research settings

The Application of Health Psychology in Public Health; Developing and Delivering Health Promotion and Behavioural Interventions

The objectives of the study were to focus on factors affecting smoking and health and to recognise and explore diversity among different groups of men. The overall aim was to gain a better understanding of men in their decision to continue or to stop smoking and the impact this may have on service provision. Seventeen semi-structured interviews with men were conducted; ten with straight men and seven with gay men. The qualitative data was analysed using grounded theory. The theme that emerged from the data was 'Reducing the potential for cognitive dissonance, caused by the action of smoking, by rationalising, normalising and minimising intrinsic and extrinsic factors and negotiating the sense of self'. These intrinsic factors included rationalising maintenance behaviour through understanding the mechanism of smoking, the availability of the product, the life-stage of the smoker, psychosocial factors and sexuality and rationalising future stopping through life changes, perceived likelihood of success and support services. The extrinsic factors included product choice, meaning of smoking on self, interpretation of health advice, health protective behaviour, their relationship with their body and the impact of legislation. These are negotiated by the image of smoking, the image of the product and masculinity. A definitive difference between the two groups to explain their desire to continue to smoke or to stop smoking was not found. The main factors that emerged and implications for service provision are discussed. The challenge for the men is to transfer an awareness of the potential dangers of smoking to themselves to make them more health conscious in the present and to accept any level of smoking behaviour as problematic

Men and smoking: An exploration of factors influencing the maintenance of smoking and smoking cessation for gay and straight men

Background: This study explored factors affecting smoking and health amongst men based on their socioeconomic status and sexuality; men from lower socio-economic groups are more likely to be smokers and there is a higher smoking prevalence within the gay population than within the general population. The aim was to gain a better understanding of the decision-making processes to continue smoking or to stop smoking and the impact this may have on stop smoking service provision. Method: 17 semi-structured interviews with men were conducted; 10 with straight men and seven with gay men. The qualitative data was analysed using grounded theory. Findings: The theme that emerged was ‘Reducing the potential for cognitive dissonance, caused by the action of smoking, by rationalising, normalising and minimising intrinsic and extrinsic factors and negotiating the sense of self’. Intrinsic factors included rationalising maintenance behaviour, availability of the product, life-stage of the smoker, psychosocial factors and sexuality. Extrinsic factors included meaning of smoking to self, interpretation of health advice, health protective behaviour and men’s relationship with their body. These are negotiated by the image of smoking, the image of the product and masculinity. Discussion: Although limited differences were found between the two groups to either continue to smoke or to stop smoking, this study illustrates the utility of health psychology when exploring approaches to behaviour change and highlights the need for an appreciation of psychosocial, economic and environmental contexts that create the lived reality when targeting and treating men to promote a ‘smokefree’ life

Performance of a new pulse contour method for continuous cardiac output monitoring: validation in critically ill patients

Background A new calibrated pulse wave analysis method (VolumeView™/EV1000™, Edwards Lifesciences, Irvine, CA, USA) has been developed to continuously monitor cardiac output (CO). The aim of this study was to compare the performance of the VolumeView method, and of the PiCCO2™ pulse contour method (Pulsion Medical Systems, Munich, Germany), with reference transpulmonary thermodilution (TPTD) CO measurements. Methods This was a prospective, multicentre observational study performed in the surgical and interdisciplinary intensive care units of four tertiary hospitals. Seventy-two critically ill patients were monitored with a central venous catheter, and a thermistor-tipped femoral arterial VolumeView™ catheter connected to the EV1000™ monitor. After initial calibration by TPTD CO was continuously assessed using the VolumeView-CCO software (CCOVolumeView) during a 72 h period. TPTD was performed in order to obtain reference CO values (COREF). TPTD and arterial wave signals were transmitted to a PiCCO2™ monitor in order to obtain CCOPiCCO values. CCOVolumeView and CCOPiCCO were recorded over a 5 min interval before assessment of COTPTD. Bland-Altman analysis, %errors, and concordance (trend analysis) were calculated. Results A total of 338 matched sets of data were available for comparison. Bias for CCOVolumeView−COREF was −0.07 litre min−1 and for CCOPiCCO-COREF +0.03 litre min−1. Corresponding limits of agreement were 2.00 and 2.48 litre min−1 (P<0.01), %errors 29 and 37%, respectively. Trending capabilities were comparable for both techniques. Conclusions The performance of the new VolumeView™-CCO method is as reliable as the PiCCO2™-CCO pulse wave analysis in critically ill patients. However, an improved precision was observed with the VolumeView™ technique. Clinicaltrials.gov identifier NCT0140504

Impact of propofol on mid-latency auditory-evoked potentials in children†

Background Propofol is increasingly used in paediatric anaesthesia, but can be challenging to titrate accurately in this group. Mid-latency auditory-evoked potentials (MLAEPs) can be used to help titrate propofol. However, the effects of propofol on MLAEP in children are unclear. Therefore, we investigated the relationship between propofol and MLAEP in children undergoing anaesthesia. Methods Fourteen healthy children aged 4-16 yr received anaesthesia for elective surgery. Before surgery, propofol was administered in three concentrations (3, 6, 9 µg ml−1) through a target-controlled infusion pump using Kataria and colleagues' model. MLAEPs were recorded 5 min after having reached each target propofol concentration at each respective concentration. Additionally, venous propofol blood concentrations were assayed at each measuring time point. Results Propofol increased all four MLAEP peak latencies (peaks Na, Pa, Nb, P1) in a dose-dependent manner. In addition, the differences in amplitudes were significantly smaller with increasing propofol target concentrations. The measured propofol plasma concentrations correlated positively with the latencies of the peaks Na, Pa, and Nb. Conclusions Propofol affects MLAEP latencies and amplitudes in children in a dose-dependent manner. MLAEP measurement might therefore be a useful tool for monitoring depth of propofol anaesthesia in childre

Automatic detection of oesophageal intubation based on ventilation pressure waveforms shows high sensitivity and specificity in patients with pulmonary disease

Background: Unrecognised endotracheal tube misplacement in emergency intubations has a reported incidence of up to 17%. Current detection methods have many limitations restricting their reliability and availability in these circumstances. There is therefore a clinical need for a device that is small enough to be practical in emergency situations and that can detect oesophageal intubation within seconds. In a first reported evaluation, we demonstrated an algorithm based on pressure waveform analysis, able to determine tube location with high reliability in healthy patients. The aim of this study was to validate the specificity of the algorithm in patients with abnormal pulmonary compliance, and to demonstrate the reliability of a newly developed small device that incorporates the technology. Materials and methods: Intubated patients with mild to moderate lung injury, admitted to intensive care were included in the study. The device was connected to the endotracheal tube, and three test ventilations were performed in each patient. All diagnostic data were recorded on PC for subsequent specificity/sensitivity analysis. Results and discussion: A total of 105 ventilations in 35 patients with lung injury were analysed. With the threshold D-value of 0.1, the system showed a 100% sensitivity and specificity to diagnose tube location. Conclusion: The algorithm retained its specificity in patients with decreased pulmonary compliance. We also demonstrated the feasibility to integrate sensors and diagnostic hardware in a small, portable hand-held device for convenient use in emergency situations

A prospective pilot study assessing levels of preoperative physical activity and postoperative neurocognitive disorder among patients undergoing elective coronary artery bypass graft surgery

Physical inactivity and a sedentary lifestyle are associated with a chronic low-level inflammatory state which has been implicated in the pathogenesis of cardiovascular disease. There is growing interest in exercise programs as part of surgical 'prehabilitation'. We therefore studied preoperative physical activity levels of patients undergoing elective Coronary Artery Bypass Graft (CABG) surgery, and performed an exploratory analysis of the influence of physical activity on postoperative outcome. The Short Questionnaire to Assess Health (SQUASH) was used to assess physical activity among 100 patients, of mean (SD) age 65.4 (7.6) years. Additionally, handgrip strength was measured, and the get-up-and-go test was conducted. Anxiety, depression, and quality of life were assessed, and a computerised cognitive test battery was used to assess cognitive performance preoperatively, and three months after surgery. Preoperatively, 76% of patients met the recommended national guidelines for physical activity. The incidence of pre-existing medical conditions, and other pre-operative patient features were similar in active and inactive patients. Preoperative physical activity was significantly inversely related to the logistic EuroSCORE. The level of physical activity was also significantly inversely related with preoperative C-reactive protein (CRP) and peak postoperative CRP, but physical activity did not appear to be associated with any adverse postoperative outcomes or extended length of hospital stay. The incidence of postoperative neurocognitive disorder (PNCD) at 3 months postoperatively was 26%. Cognitive performance was not related with physical activity levels. In summary, this was the first study to assess activity levels of cardiac surgical patients with the SQUASH questionnaire. The majority of patients were physically active. Although physical activity was associated with lower levels of inflammation in this pilot study, it was not associated with an improved clinical or cognitive postoperative outcome

Brain changes due to hypoxia during light anaesthesia can be prevented by deepening anaesthesia:a study in rats

In anaesthetic practice the risk of cerebral ischemic/hypoxic damage is thought to be attenuated by deep anaesthesia. The rationale is that deeper anaesthesia reduces cerebral oxygen demand more than light anaesthesia, thereby increasing the tolerance to ischemia or hypoxia. However, evidence to support this is scarce. We thus investigated the influence of light versus deep anaesthesia on the responses of rat brains to a period of hypoxia. In the first experiment we exposed adult male Wistar rats to deep or light propofol anaesthesia and then performed [18F]- Fludeoxyglucose (FDG) Positron Emission Tomography (PET) scans to verify the extent of cerebral metabolic suppression. In subsequent experiments, rats were subjected to light/deep propofol anaesthesia and then exposed to a period of hypoxia or ongoing normoxia (n = 9-11 per group). A further 5 rats, not exposed to anaesthesia or hypoxia, served as controls. Four days later a Novel Object Recognition (NOR) test was performed to assess mood and cognition. After another 4 days, the animals were sacrificed for later immunohistochemical analyses of neurogenesis/neuroplasticity (Doublecortin; DCX), Brain Derived Neurotrophic Factor (BDNF) expression and neuroinflammation (Ionized calcium-binding adaptor protein-1; Iba-1) in hippocampal and piriform cortex slices. The hippocampi of rats subjected to hypoxia during light anaesthesia showed lower DCX positivity, and therefore lower neurogenesis, but higher BDNF levels and microglia hyper-ramification. Exploration was reduced, but no significant effect on NOR was observed. In the piriform cortex, higher DCX positivity was observed, associated with neuroplasticity. All these effects were attenuated by deep anaesthesia. Deepening anaesthesia attenuated the brain changes associated with hypoxia. Hypoxia during light anaesthesia had a prolonged effect on the brain, but no impairment in cognitive function was observed. Although reduced hippocampal neurogenesis may be considered unfavourable, higher BDNF expression, associated with microglia hyper-ramification may suggest activation of repair mechanisms. Increased neuroplasticity observed in the piriform cortex supports this, and might reflect a prolonged state of alertness rather than damage