Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2004
ReviewPulse transit time by R-wave-gated infrared photoplethysmography: review of the literature and personal experience.
Pulse transit time (PTT) is the time it takes a pulse wave to travel between two arterial sites. A rela tively short PTT is observed with high blood pressure (BP), aging, arteriosclerosis and diabetes mellitus. Most methods used for measuring the PTT are cumbersome and expensive. In contrast, the interval between the peak of the R-wave on the electrocardiogram and the onset of the corresponding pulse in the finger pad measured by photoplethysmography can be easily measured. We review herein the literature and impart the experience at our institution on clinical applications of R-wave-gated photo-plethysmography (RWPP) as measurement of PTT. ⋯ In clinical practice, sleep-apnea may be accurately monitored by RWPP. RWPP seems to reflect autonomic influences and may be particularly well-suited for the study of vascular reactivity. Thus, further descriptions of disease-specific cardiovascular reactivity patterns may be possible with techniques based on RWPP. Other clinical uses of RWPP are investigational.
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J Clin Monit Comput · Dec 2004
Interactive simulation system for artificial ventilation on the internet: virtual ventilator.
To develop an interactive simulation system "virtual ventilator" that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. ⋯ We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.
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J Clin Monit Comput · Dec 2004
Randomized Controlled Trial Clinical TrialThe effects of two different anaesthesia techniques on bispectral index values and awareness during off-pump coronary artery bypass grafting.
The aim of this study was to evaluate Bispectral Index values and awareness during two different anaesthesia regimens (fentanyl-propofol and fentanyl-midazolam) in patients undergoing off-pump CABG surgery. ⋯ BIS monitoring with clinical signs may be used to assess the adequacy of both types of anaesthesia techniques as well as to detect awareness during off-pump CABG surgery.
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In order to reduce losses of gases through plastic components and to reduce nitrogen accummulation during closed system anaesthesia we investigated either 10 sets of anaesthetic tubing made of silicon as used in standard clinical practice and 10 sets made of latex, which are not used anymore due to concerns about latex allergies. The results were compared to each one set made of conventional industrial rubber. ⋯ If closed anaesthetic systems in the future will be used in intensive care therapy or in case of long lasting procedures in which closed system anaesthesia is proceeded, materials other than silicone should be investigated to avoid regular purging of system and consecutive losses of gas mixtures.
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J Clin Monit Comput · Dec 2004
Initial transcutaneous PCO2 overshoot with ear probe at 42 degrees C.
To investigate an unexpectedly high initial skin CO2 pressure with a new small earlobe probe* heated to 42 degrees C containing both transcutaneous (tcPCO2) and pulse oximeter saturation (SpO2) sensors. ⋯ A temperature of 42 degrees C may increase local skin temperature and metabolism before vasodilating more remote arteriolar control of sub-sensor capillary flow. We suggest that transcutaneous PCO2 probes be initially set to 44 - 45 degrees C for 5 - 15 min to induce prompt vasodilation to prevent this overshoot and then reduced to 42 degrees C to avoid skin thermal injury in case of long-term application.