Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2005
Case ReportsTo do or not to do a preinduction check-up of the anesthesia machine.
The anesthesia machine check is an integral part of the anesthesiologist's daily routine. It is standard operating procedure to check the high- and low-pressure systems of the machine as well as other integral parts that are accessible. Many new anesthesia machines offer a self-testing capability, but older ones with fewer electronics on board are still widely used. ⋯ In our case we encountered an open CO2 absorber after a service of the machine had been performed between the cases without our knowledge. We were unable to ventilate the patient during induction. The presence of a backup self-filling manual ventilation bag was invaluable in preventing an otherwise inevitable emergency.
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Anesthesia and analgesia · Sep 2005
An algorithm for processing vital sign monitoring data to remotely identify operating room occupancy in real-time.
We developed an algorithm for processing networked vital signs (VS) to remotely identify in real-time when a patient enters and leaves a given operating room (OR). The algorithm addresses two types of mismatches between OR occupancy and VS: a patient is in the OR but no VS are available (e.g., patient is being hooked up), and no patient is in the OR but artifactual VS are present (e.g., because of staff handling of sensors). The algorithm was developed with data from 7 consecutive days (122 cases) in a 6 OR trauma center. ⋯ Identified patient in- and out-times were accurate within 4.9 min (CI 4.2-5.7) and 2.8 min (CI 2.3-3.5), respectively, and were not different in accuracy from times reported by staff on OR records. The algorithm's usefulness was demonstrated partly by its continued operational use. We conclude that VS can be processed to accurately report OR occupancy in real-time.
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Automatic muscle relaxation control may reduce anesthesiologists' workload freeing them for other patient care requirements. In this report we describe a muscle relaxation controller designed for routine clinical application using rocuronium and the train-of-four count. A muscle relaxation monitor (TOF Watch SX) was connected to a laptop computer running a controller algorithm program that communicates with a syringe pump to form a closed-loop muscle relaxation system. ⋯ Average rocuronium infusion rate was 0.36 mg.kg(-1).h(-1) (sd 0.18 mg.kg(-1).h(-1)). We show that the controller remains useful even in the presence of disturbances that can arise in routine clinical conditions. The muscle relaxation controller maintained the target train-of-four count values and may serve as a basis for the design of hardware and user interfaces for closed-loop muscle relaxation control in clinical conditions.
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Anesthesia and analgesia · Sep 2005
Tutorial: context-sensitive decrement times for inhaled anesthetics.
Context-sensitive decrement times for inhaled anesthetics connect two values: a) the duration of anesthesia (nominally at a constant alveolar concentration)-the "context" and b) the time to decrease the alveolar or vital tissue (e.g., brain, heart, kidney, and liver, collectively called the vessel-rich group of tissues) concentration by some fractional "decrement" of the starting concentration. Increasing duration of anesthesia increases the time to a given decrement in a nonlinear manner that may considerably delay recovery. In the present report we use a commercially available simulation program (Gas Man) to confirm and enlarge on these concepts. ⋯ For desflurane, only prolonged anesthesia or decrements of 95% and more should delay awakening from anesthesia. These changes are shown to be the result of the relative solubility of each anesthetic in blood and tissue. An increase in cardiac output is also shown to delay awakening.
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Anesthesia and analgesia · Sep 2005
Clinical TrialAnalysis of the bispectral index during natural sleep in children.
The Bispectral Index (BIS) is a system used to measure sedation levels. Some investigators recently analyzed changes in the BIS during natural sleep in adults and found that the BIS diminished considerably as sleep became deeper. No such studies have been undertaken to investigate changes in the BIS in sleeping children. ⋯ The results showed that the BIS decreased progressively as sleep became deeper. The correlation between the stage of sleep and the BIS was significant. On reawaking, a slow increase was apparent in the BIS.