Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Monitoring of isoflurane and desflurane breakdown: interfering gases and infrared detection.
The reaction of isoflurane, enflurane or desflurane with dried CO2 absorbents produces carbon monixide (CO), a highly toxic gas which cannot be detected by gas monitors typically available in the operating room. Trifluoromethane (CHF3) is produced along with CO when this reaction occurs with isoflurane and desflurane, and can be detected by gas monitors. This study will determine the ability of a modified SAM module (Smart Anesthesia Multigas Module, GE/Marquette Medical Systems, Milwaukee, WI) to identify the presence of CHF3, and provide a clinically useful indirect warning of CO production. ⋯ We have shown that the SAM module is capable of measuring CHF3 due to anesthetic breakdown. With appropriate changes in the display programming and reference cell spectra the monitor would be able to provide an early warning of CO exposure, although the amount of CO would not be reported.
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J Clin Monit Comput · Jan 2000
Determining the artifact sensitivity of recent pulse oximeters during laboratory benchmarking.
This study aimed to investigate and compare the performance of the algorithms contained in the newest generation of pulse oximeters (Masimo SET in IVY2000, Nellcor Oxismart N-3000, Agilent M3 rev. B) against a traditional pulse oximeter (Agilent CMS rel. A.0). ⋯ Very pronounced improvements (between 2.3 and 3.4 fold) on all of the newer devices were found for the pulse rate. The NMC turned out to be a very useful tool for generating a standard signal set for algorithm development and benchmarking purposes that eliminates repetitive clinical testing in early stages. The applicability of its results needs confirmation by clinical live studies.
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J Clin Monit Comput · Jan 2000
Teaching respiratory physiology: clinical correlation with a human patient simulator.
In recent years students have increasingly objected to laboratory exercises involving animal subjects. We have replaced the valuable animal experiments with demonstrations using a full-scale human patient simulator. In small groups first-year medical students observe realistic clinical situations such as opioid-induced hypoventilation, pneumothorax, and pulmonary edema. ⋯ They practice interventions such as providing supplemental oxygen and mask ventilation, monitor the results, and develop a basic differential diagnosis and treatment plan. We utilize the clinical context to review fundamental concepts of respiratory physiology including the alveolar air equation and oxyhemoglobin dissociation curve. The students give these laboratory exercises uniformly superior evaluations.
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J Clin Monit Comput · Jan 2000
Local cardiac wall stabilization influences the reproducibility of regional wall motion during off-pump coronary artery pass surgery.
Myocardial ischemia is a risk factor during off-pump coronary artery bypass procedures. The development of new regional wall motion abnormalities assessed by transesophageal echocardiography (TEE) is a very sensitive sign of myocardial ischemia. To facilitate anastomosis, the epicardial area of the anastomosis site is often immobilized by a "stabilizer." This study was designed to investigate whether cardiac wall stabilization with an epicardial stabilizer could affect the interpretation of wall motion during coronary anastomosis without cardiopulmonary bypass. ⋯ Cardiac wall stabilization affects the reproducibility in the interpretation of regional wall motion during off-pump coronary artery bypass surgery. Caution should be used when monitoring for myocardial ischemia using TEE during coronary artery bypass surgery with epicardial stabilizer.
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J Clin Monit Comput · Jan 2000
Influence of tidal volume and thoraco-abdominal separation on the respiratory induced variation of the photoplethysmogram.
The present study was aimed at determining the relative influences of tidal volume and thoraco-abdominal separation (relative thoracic and abdominal contribution to the tidal volume) on the respiratory induced intensity variation (RIIV) of the photoplethysmographic signal. The effects were studied in two body positions. ⋯ The effects on the RIIV signal following changes in thoraco-abdominal separation and tidal volume are of the same order of magnitude. In the supine position, the influence of thoracic versus abdominal contribution to the tidal volume is not as significant as in the sitting position. Photoplethysmography is a promising technique for combined monitoring of several respiratory parameters, including tidal volume. In situations where the relative thoracic and abdominal contributions are likely to vary, the tidal volume information becomes less reliable.