An Evaluation of the Hybrid Model for Predicting Surgery Duration.

The degree of accuracy in surgery duration estimation directly impacts on the quality of planned surgical lists. Model selection for the prediction of surgery duration requires technical expertise and significant time and effort. The result is often a collection of viable models, the performance of which varies across different strata of the surgical population. This paper proposes a prediction framework to be used after a comprehensive model selection process has been completed for surgery duration prediction. The framework produces a partition of the surgical cases and a "hybrid model" that allocates different predictors from the collection of viable models to different parts of the surgical population. The intention is a flexible prediction process that can reassign models and adapt as surgical processes change. The framework is tested via a simulation study, and its utility is demonstrated by predicting surgery durations for Ear, Nose and Throat surgeries in a New Zealand hospital. The results indicate that the hybrid model is effective, performing better than standard model selection in two of the three simulation studies, and marginally worse when the selected model was the true underlying process.

A Literature Review on Validated Simulations of the Surgical Services.

The surgical department is a critical unit that oversees multiple surgical-based clinical pathways and works with various other units in a hospital. This department faces numerous challenges relating to variability in demand and management of resources. The aim of this article is to review the application of validated simulation models on hospital-wide surgical services. Each of these models is broadly classified by (i) simulation method and (ii) level of detail given to the management of "patient pathways" and "staff workflows". We remark that very few studies have given attention to the management of staff workflows in their validated simulation models.

Simultaneous liver and kidney transplantation from different living donors.

OBJECTIVES: To present our experience with simultaneous living donor liver and kidney (SLK) transplantation from two different living donors. PATIENTS AND METHODS: We performed five SLK transplantations from two different living donors from November 2006 to December 2010. Four patients were males and one, female. Their age range was 47 to 66 years (mean, 55 years). The primary liver diseases included hepatitis B virus (n=2), alcoholic liver cirrhosis (n=2), cryptogenic liver disease (n=1), and hepatitis C virus with hepatocellular carcinoma (n=1). All five patients had chronic renal failure: four were on hemodialysis (H/D) and one on chronic ambulatory peritoneal dialysis for 1 to 20 years. Liver implantation was performed first, followed by kidney transplantation. The liver and kidney teams worked closely to shorten the ischemia time. RESULTS: All surgical procedures were performed uneventfully and all recipients and donors survived the operations. Good liver graft function was noted in all five patients. The patient with both anti-T- and anti-B-cell positive crossmatch tests developed hyperacute rejection of the kidney graft requiring its immediate removal. This patient was maintained on regular H/D afterward. The other four patients displayed good renal function. No evidence of severe acute rejection was noted during the follow-up period (range, 9-55 months) among patients treated with tacrolimus-based immunosuppression. CONCLUSION: We suggest that SLK transplantation be performed with organs from two different instead of a single live donor.

Action research studies in the intensive care setting: a systematic review.

OBJECTIVES: To review published studies using action research in the intensive care unit (ICU) in order to provide an intervention framework to improve clinical outcomes. DESIGN: Systematic review. METHODS: Searches of the electronic databases: Cumulative Index of Nursing and Allied Health Literature (CINAHL); Scopus, Medline, Embase, PsycINFO, and the World Wide Web were undertaken using MeSH key words including: 'action research'; 'health care research', 'health services evaluation'; 'intensive care unit'. Reference lists of retrieved articles was also undertaken to identify further articles. All studies were reviewed by two authors using a critical appraisal tool. RESULTS: The search strategy generated 195 articles. Only 21 studies projects were identified using action research in the ICU. The majority of studies were conducted in the United Kingdom. The participants in the action research studies ranged from 6 to 253. Predominately studies using action research involved nurses in collaboration with patients and family and other health care practitioners to address identified problems in the ICU. CONCLUSIONS: Based on this review it appears that action research is a promising methodological approach to address clinical practice improvement in the ICU. Studies retrieved focussed primarily on process and formative evaluation but not on clinical outcomes. There is a need to incorporate outcome assessment in action research in the ICU to increase the framework of action research to improve clinical outcomes.

Contrast-enhancing optical method to observe a Bonghan duct floating inside a lymph vessel of a rabbit.

Novel threadlike structures, so-called Bonghan ducts (BHDs), were recently rediscovered inside large caliber lymphatic vessels using two different staining dyes in rabbits (Janus green B and Alcian blue) and fluorescent nanoparticles in rats. These three methods have the drawback of injecting chemical agents into the lymphatic vessels, which might damage the BHD and hinder further investigation of its physiological function. New methods to observe BHDs without using external chemical agents need to be developed. In the present work, we introduce a contrast enhancing optical method for in vivo observation of BHDs floating inside large caliber lymph vessels. The method uses a low-pass filter above about 650 nm, with an arrangement to minimize the light reflected from the surface of the lymph vessel. We captured films showing movement of a BHD as the animal respired. Applying the previous Alcian blue injection technique, we obtained BHD samples from the lymph vessel and observed the distribution of rod-shape nuclei (the essential feature of a BHD). BHDs can now be observed inside lymph vessels by using contrast-enhancing instrumentation without visualizing chemical agents.

Biophoton emission of MDCK cell with hydrogen peroxide and 60 Hz AC magnetic field.

We studied biophoton characteristics of Madin-Darby canine kidney (MDCK) cells under the influence of H2O2 by employing a photomultiplier tube (PMT) and a fluorescence microscope. H2O2 was used for producing reactive oxygen species (ROS) in the measurement. Images from a fluorescence microscope show an increase of photon intensity emitted from the sample due to H2O2. By using a PMT we measured quantitative change in biophoton emission with application of H2O2 to the MDCK cell culture, found that the increase of the biophoton is dependent upon the amount of H2O2. The agreement between the results of the PMT and the fluorescence microscope suggests the possibility of quantitative measurement of the influence of ROS on living tissue or cell. In addition we applied a 60 HzAC magnetic field on the cells to investigate the change in reaction between MDCK cell and ROS. It showed that a decay of chemiluminescence intensity has taken a different path following exposure to the magnetic field. As a result, the PMT measurement might be considered as a useful tool for studying biochemical characteristics in relation to ROS.

Changes in ultraweak photon emission and heart rate variability of epinephrine-injected rats.

Ultraweak photons which are spontaneously emitted from a living body may be applicable as a non-invasive tool to characterize the physiological state of the living body. We investigated changes in the intensity of ultraweak photon emission, body temperature and the cardiovascular autonomic activity induced by epinephrine injection to rats. A high dose of epinephrine can make changes to the cardiovascular autonomic activity or body temperature. Photon emission of the dorsal part, rectal temperature and heart rate variability (HRV) were measured from eight Sprague-Dawley rats. The intensities of photon emissions for saline injections, which were used as a control, decreased from 13042+/-71 counts/min at the start of measurements to 8709+/-915 counts/min at 1 h after the injections. In the case with epinephrine injections, the intensity of photon emission reduced slowly from 13361+/-354 counts/min to 11040+/-433 counts/min. Rectal temperature increased in both saline- and epinephrine-injected rats, but one hour after the injections the temperature in the epinephrine case was slightly higher than that in the saline case. The standard deviation of the QRS wave complex interval (RR interval) increased from 1 to 4 (p<0.05) and the spectral ratio of the low frequency component to the high frequency component in the HRV data LF (0.19 approximately 0.74 Hz) / HF (0.78 approximately 2.50 Hz) decreased from 0.81 to 0.26 (p<0.05) in the case of epinephrine injection while no change was found in the case of saline injection. Thus, ultraweak photon emission was closely related to the cardiovascular autonomic activity.

Influence of exposure to electromagnetic field on the cardiovascular system.

1 We examined whether extremely low frequency electromagnetic fields (ELF-EMF) affect the basal level of cardiovascular parameters and influence of drugs acting on the sympathetic nervous system. 2 Male rats were exposed to sham control and EMF (60 Hz, 20 G) for 1 (MF-1) or 5 days (MF-5). We evaluated the alterations of blood pressure (BP), pulse pressure (PP), heart rate (HR), and the PR interval, QRS interval and QT interval on the electrocardiogram and dysrhythmic ratio in basal level and dysrhythmia induced by beta-adrenoceptor agonists. 3 In terms of the basal levels, there were no statistically significant differences among control, MF-1 and MF-5 in PR interval, QRS interval, mean BP, HR and PP. However, the QT interval, representing ventricular repolarization, was significantly reduced by MF-1 (P < 0.05). 4 (-)-Dobutamine (beta1-adrenoceptor-selective agonist)-induced tachycardia was significantly suppressed by ELF-EMF exposure in MF-1 for the increase in HR (DeltaHR), the decrease in QRS interval (DeltaQRS) and the decrease in QT (DeltaQT) interval. Adrenaline (nonselective beta-receptor agonist)-induced dysrhythmia was also significantly suppressed by ELF-EMF in MF-1 for the number of missing beats, the dysrhythmic ratio, and the increase in BP and PP. 5 These results indicated that 1-day exposure to ELF-EMF (60 Hz, 20 G) could suppress the increase in HR by affecting ventricular repolarization and may have a down-regulatory effect on responses of the cardiovascular system induced by sympathetic agonists.

Juvenile angiofibroma: case report and the role of endoscopic resection.

Juvenile angiofibroma is benign yet aggressive. Due to its inaccessible location in the nasopharynx, open surgery usually requires osteotomies which cause stunting of facial growth in adolescent males. Advances in imaging and treatment techniques have now facilitated more accurate staging of this disease. For small, extracranial tumours limited to the nasal cavity and paranasal sinus, endoscopic resection is a viable alternative. This case report will illustrate how endoscopic resection allows good control with minimal morbidity compared to open surgery or radiotherapy.

Pulse type classification by varying contact pressure.

We introduced a new technique of quantification of pulse characteristics in connection with contact pressure. We provided data only for illustrative purposes, deferring statistical analysis of samples of a larger population. This quantification can be useful for diagnostic purposes; for example, by detecting changes of the three quantities according to the health condition or particular disease of a patient, or by analyzing correlations among these quantities and other physiological variables.

Sphenochoanal polyps in Singapore: diagnosis and current management.

Sphenochoanal polyp is a rare form of choanal polyp. If unrecognised, they can be mistaken for an antrochoanal polyp. This will result in unnecessary exploration of the maxillary sinus, and a failure to remove the sphenoidal component of the sphenochoanal polyp. Adequate preoperative evaluation with computed tomography or magnetic resonance is mandatory to ascertain the correct diagnosis, and to facilitate the planning of the appropriate surgical procedure. We present two patients with sphenochoanal polyp and a review of the literature.

Exact wave functions in a noncommutative field theory.

We consider the nonrelativistic field theory with a quartic interaction on a noncommutative plane and compute the 2-->2 scattering amplitude within perturbative analysis to all orders. We regain the results of the perturbative analysis by finding the scattering and the bound state wave functions of the two particle Schrodinger equation. These wave functions unusually have two center positions in the relative coordinates, whose separation is transverse to the total momentum and scales linearly with its magnitude, exhibiting the stringy nature of the noncommutative field theory.

Synchronization and resonance in a driven system of coupled oscillators.

We study the noise effects in a driven system of globally coupled oscillators, with particular attention to the interplay between driving and noise. The self-consistency equation for the order parameter, which measures the collective synchronization of the system, is derived; it is found that the total order parameter decreases monotonically with noise, indicating overall suppression of synchronization. Still, for large coupling strengths, there exists an optimal noise level at which the periodic (ac) component of the order parameter reaches its maximum. The response of the phase velocity is also examined and found to display resonance behavior.

The glossopharyngeal nerve, glossopharyngeal neuralgia and the Eagle's syndrome--current concepts and management.

Glossopharyngeal neuralgia is not just a painful condition. At times, it may be life-threatening as a result of associated cardiovascular consequences. Even in the absence of life-threatening consequences, it can be a severe debilitating disease with depression, suicidal tendencies, fear of swallowing, loss of weight and under-nutrition. The treatment for glossopharyngeal neuralgia and Eagle's syndrome has evolved over time. This review summarises the scientific evidence and philosophy about current management and therapy. Emphasis is placed on the importance of excluding secondary causes of glossopharyngeal neuralgia before embarking on nerve section through the posterior cranial fossa approach. The Eagle's syndrome due to an elongated styloid process is the most important cause of secondary glossopharyngeal neuralgia. Stylectomy is effective and should be considered before embarking on any neurosurgical procedure. Peripheral cervical and trans-tonsillar approaches to the glossopharyngeal nerve are also discussed.