Examination of Driver Visual and Cognitive Responses to Billboard Elicited Passive Distraction Using Eye-Fixation Related Potential.

Distractions external to a vehicle contribute to visual attention diversion that may cause traffic accidents. As a low-cost and efficient advertising solution, billboards are widely installed on side of the road, especially the motorway. However, the effect of billboards on driver distraction, eye gaze, and cognition has not been fully investigated. This study utilises a customised driving simulator and synchronised electroencephalography (EEG) and eye tracking system to investigate the cognitive processes relating to the processing of driver visual information. A distinction is made between eye gaze fixations relating to stimuli that assist driving and others that may be a source of distraction. The study compares the driver's cognitive responses to fixations on billboards with fixations on the vehicle dashboard. The measured eye-fixation related potential (EFRP) shows that the P1 components are similar; however, the subsequent N1 and P2 components differ. In addition, an EEG motor response is observed when the driver makes an adjustment of driving speed when prompted by speed limit signs. The experimental results demonstrate that the proposed measurement system is a valid tool in assessing driver cognition and suggests the cognitive level of engagement to the billboard is likely to be a precursor to driver distraction. The experimental results are compared with the human information processing model found in the literature.

Design of a novel photosensitive phantom for the accurate calibration of the temporal response of electroencephalography systems.

This paper describes a novel method to measure the temporal latency of electroencephalography (EEG) systems using a customized photosensitive phantom. The system was evaluated with three different EEG devices, a medical grade (g.Tec), a consumer grade (Emotiv), and a low-cost device (Arduino SpikerShield). The temporal latencies of the three EEG devices were measured. The proposed method can be easily adapted to assess other EEG devices. The measurements obtained in this experiment provided concrete data for future experiments where accurate timing data are critical.

Analysis of glottal source parameters in Parkinsonian speech.

Diagnosis and monitoring of Parkinson's disease has a number of challenges as there is no definitive biomarker despite the broad range of symptoms. Research is ongoing to produce objective measures that can either diagnose Parkinson's or act as an objective decision support tool. Recent research on speech based measures have demonstrated promising results. This study aims to investigate the characteristics of the glottal source signal in Parkinsonian speech. An experiment is conducted in which a selection of glottal parameters are tested for their ability to discriminate between healthy and Parkinsonian speech. Results for each glottal parameter are presented for a database of 50 healthy speakers and a database of 16 speakers with Parkinsonian speech symptoms. Receiver operating characteristic (ROC) curves were employed to analyse the results and the area under the ROC curve (AUC) values were used to quantify the performance of each glottal parameter. The results indicate that glottal parameters can be used to discriminate between healthy and Parkinsonian speech, although results varied for each parameter tested. For the task of separating healthy and Parkinsonian speech, 2 out of the 7 glottal parameters tested produced AUC values of over 0.9.

An evaluation of ciprofloxacin pharmacokinetics in critically ill patients undergoing continuous veno-venous haemodiafiltration.

BACKGROUND: The study aimed to investigate the pharmacokinetics of intravenous ciprofloxacin and the adequacy of 400 mg every 12 hours in critically ill Intensive Care Unit (ICU) patients on continuous veno-venous haemodiafiltration (CVVHDF) with particular reference to the effect of achieved flow rates on drug clearance. METHODS: This was an open prospective study conducted in the intensive care unit and research unit of a university teaching hospital. The study population was seven critically ill patients with sepsis requiring CVVHDF. Blood and ultrafiltrate samples were collected and assayed for ciprofloxacin by High Performance Liquid Chromatography (HPLC) to calculate the model independent pharmacokinetic parameters; total body clearance (TBC), half-life (t1/2) and volume of distribution (Vd). CVVHDF was performed at prescribed dialysate rates of 1 or 2 L/hr and ultrafiltration rate of 2 L/hr. The blood flow rate was 200 ml/min, achieved using a Gambro blood pump and Hospal AN69HF haemofilter. RESULTS: Seventeen profiles were obtained. CVVHDF resulted in a median ciprofloxacin t1/2 of 13.8 (range 5.15-39.4) hr, median TBC of 9.90 (range 3.10-13.2) L/hr, a median Vdss of 125 (range 79.5-554) L, a CVVHDF clearance of 2.47+/-0.29 L/hr and a clearance of creatinine (Clcr) of 2.66+/-0.25 L/hr. Thus CVVHDF, at an average flow rate of ~3.5 L/hr, was responsible for removing 26% of ciprofloxacin cleared. At the dose rate of 400 mg every 12 hr, the median estimated Cpmax/MIC and AUC0-24/MIC ratios were 10.3 and 161 respectively (for a MIC of 0.5 mg/L) and exceed the proposed criteria of >10 for Cpmax/MIC and > 100 for AUC0-24/MIC. There was a suggestion towards increased ciprofloxacin clearance by CVVHDF with increasing effluent flow rate. CONCLUSIONS: Given the growing microbial resistance to ciprofloxacin our results suggest that a dose rate of 400 mg every 12 hr, may be necessary to achieve the desired pharmacokinetic-pharmacodynamic (PK-PD) goals in patients on CVVHDF, however an extended interval may be required if there is concomitant hepatic impairment. A correlation between ciprofloxacin clearance due to CVVHDF and creatinine clearance by the filter was observed (r2 = 0.76), providing a useful clinical surrogate marker for ciprofloxacin clearance within the range studied. TRIAL REGISTRATION: Current Controlled Trials ISRCTN52722850.

Anesthetic technique and the cytokine and matrix metalloproteinase response to primary breast cancer surgery.

BACKGROUND: Breast cancer is the most common malignancy in women. Surgery remains the most effective treatment. Several perioperative factors, including the surgical stress response, many anesthetics and opioids, adversely affect immune function. Regional anesthesia-analgesia attenuates perioperative immunosuppression. We tested the hypothesis that patients who receive combined propofol/paravertebral anesthesia-analgesia (propofol/paravertebral) exhibited reduced levels of protumorigenic cytokines and matrix metalloproteinases (MMPs) and elevated levels of antitumorigenic cytokines compared with patients receiving sevoflurane anesthesia with opioid analgesia (sevoflurane/opioid). METHODS: Primary breast cancer surgery patients were randomized to propofol/paravertebral (n = 15) or sevoflurane/opioid (n = 17) and preoperative and postoperative serum concentrations of 11 cytokines (interleukin 1ß [IL-1ß], IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon γ, and tumor necrosis factor α) and 3 MMPs (MMP-1, MMP-3, and MMP-9) were measured. RESULTS: Treatment groups were well balanced for age, weight, surgical procedure, and cancer pathologic diagnosis. Pain scores were lower at 1 and 2 hrs with paravertebral analgesia compared with morphine but similar at 24 hrs. Patients in the propofol/paravertebral group showed a greater percentage decrease in postoperative compared with preoperative IL-1ß (median [quartiles], -26% [-15% to -52%] versus -4% [-14% to 2%], P = 0.003), a significant attenuation in elevated MMP-3 (2% [-39% to 12%] versus 29% [23%-59%], P = 0.011) and MMP-9 (26% [13%-54%] versus 74% [50%-108%], P = 0.02), and a significant increase in IL-10 (10% [5%-33%] versus -15% [20% to -2%], P = 0.001) compared with sevoflurane/opioid group. No significantly different changes in IL-2, IL-4, IL-5, IL-6, IL-8, IL-12p70, IL-13, interferon γ, tumor necrosis factor α, or MMP-1 were observed between the 2 groups. CONCLUSIONS: Propofol/paravertebral anesthesia-analgesia for breast cancer surgery alters a minority of cytokines influential in regulating perioperative cancer immunity. Further evaluation is required to determine the significance of these observations.

Amitriptyline poisoning in a 2-year old.

We describe a case of a 2-year-old boy who ingested 35 mg.kg(-1) of amitriptyline. He developed central nervous system toxicity, as demonstrated by coma and seizures and cardiac toxicity (cardiac arrest) within 1 h of ingestion. The cardiac toxicity was refractory to standard therapy. His cardiac rhythm alternated between ventricular tachycardia and pulseless ventricular tachycardia/ventricular fibrillation for a period of 17 h. Following prolonged cardiopulmonary resuscitation and aggressive supportive management, the patient recovered both cardiovascularly and neurologically. An echocardiogram and MRI brain were subsequently performed and were normal. The patient was discharged 2 weeks later with normal cognitive, behavioral and motor function. We discuss the benefit of prolonged and effective cardiopulmonary resuscitation in the management of this potentially fatal poisoning.

Design and implementation of an end tidal CO2 simulator for the evaluation of clinical gas analysers.

This paper presents a new technique to determine the dynamic and frequency response of capnographs using a custom built 'EtCO2 simulator system'. Capnographs are devices that use CO2 from a patients' expired breath to monitor the cardiopulmonary status during anaesthesia and mechanical ventilation. Capnographs at present are routinely calibrated via a static calibration method only. The dynamic response of the capnographs is not accounted for. The frequency and time response are important as they determine if capnographs can be used in high frequency and pediatric ventilation schemes. Experiments performed using the method described in this paper proved that old capnographs usually do not satisfy the manufacturer quoted specifications for time and frequency response. Therefore, a routine check for capnographs is recommended. The method can also be used to verify manufacturer quoted specifications. The EtCO2 simulator system, designed and constructed simulates human respiration cycle. The gas sources used are 5% CO2 and room air that can be switched alternatively. Both supplies are pressure regulated and connected through non-return valves to electric valves. The valves are microprocessor controlled and the on/off time is user defined allowing a wide range of waveforms to be simulated. The output from the simulator is delivered to capnograph. Capnograms are captured by digital video recording. The captured video in 'avi' file format is then converted into individual frames. These frames are converted into digital data through image processing in Matlab. The data obtained is subjected to extensive analysis to determine the frequency and time response of the respective capnograph.