Acta anaesthesiologica Belgica
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Acta Anaesthesiol Belg · Jan 1990
Clinical evaluation of pulse oximetry monitors on critically ill patients.
Four pulse oximeters and two pulse oximeter-capnographs were evaluated on accuracy of measuring oxygen saturation and heartrate for the former and oxygen saturation, heartrate, respiratory rate and capnography for the latter. In the first part of the study four pulse oximeters (Criticare Systems Model 501 +, Ohmeda Biox 3700 Pulse Oximeter, Nellcor Model N 100 and Datex Satlite) were simultaneously studied on 10 ventilated ICU patients. Fifty simultaneous measurements were done for heartrate and oxygen saturation and compared to arterial saturations and ECG heartrates. ⋯ As in the first part of the study all results were accurate within two percent of control values. From those data we can conclude that all examined monitors were fairly accurate compared to simultaneous arterial blood gas analysis and ECG monitoring. The oxicap monitors have the advantage of giving continuous information on two very important parameters of patient monitoring: CO2 and saturation.
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Opinions vary on the monitoring requirements associated with low flow to closed circuit anesthesia. Fresh gas flow rate affects variables of anesthesia ventilation such as the time constant of the breathing system, the inspired concentrations of O2, N2O and anesthetic vapor and the potential for rebreathing. ⋯ However, none of these safety monitors is beyond the scope of the "essential requirements" proposed for anesthesia workstations by international standard-writing groups, such as CEN or ISO. It may hence be concluded that fresh gas flow rate does affect variables to be monitored, but it does not affect essential monitoring requirements.
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Acta Anaesthesiol Belg · Jan 1990
The climatisation of anesthetic gases under conditions of high flow to low flow.
The aim of climatisation of anesthetic gases in prolonged anesthesia is to maintain tracheobronchial climate comparable to that of spontaneous nasal breathing. The humidity and temperature of inspired gases attained in the circle system at a fresh gas flow of 6.0, 3.0 and 1.5 l/min are inadequate for prolonged anesthesia. According to the results of our study with the scanning electron microscope, the minimal flow technique (0.5 l/min) leads to major improvement of heat (28 to 32 degrees C) and moisture (20 to 27 mg H2O/l) conditions of anesthetic gases in anesthesia systems.
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Acta Anaesthesiol Belg · Jan 1990
Respiratory diagnostic possibilities during closed circuit anesthesia.
An automatic feed back controlled totally closed circuit system (Physioflex) has been developed for quantitative practice of inhalation anesthesia and ventilation. In the circuit system the gas is moved unidirectionally around by a blower at 70 l/min. In the system four membrane chambers are integrated for ventilation. ⋯ Disregulations of metabolism, e.g. in malignant hyperthermia, are seen in a pre-crisis phase (increase of oxygen consumption and of CO2 production), and therapy can be started extremely early and before a disastrous condition has developed. Registration of compliance is only one of the continuously available parameters that guarantee a better and adequate control of lung function (e.g. atalectasis is early detected). The newly developed sophisticated anesthesia device enlarges tremendously the monitoring and respiratory diagnostic possibilities of artificial ventilation, gives new insights in the (patho)physiology and detects disturbances of respiratory parameters and metabolism in an early stage.