Anesthesia and analgesia
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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
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.
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Anesthesia and analgesia · Sep 2005
Sepsis produced by Pseudomonas bacteremia does not alter plasma volume expansion after 0.9% saline infusion in sheep.
Clinicians generally consider sepsis to be a state in which fluid is poorly retained within the vasculature and accumulates within the interstitium. We hypothesized that infusion of 0.9% saline in conscious, chronically instrumented sheep with hyperdynamic bacteremic sepsis would be associated with less plasma volume expansion (PVE) and greater interstitial fluid volume expansion than in conscious, nonseptic sheep. Six conscious adult sheep received an IV infusion of 25 mL/kg of 0.9% saline over 20 min (1.25 mL.kg(-1).min(-1)) in a control nonseptic state and during early and late sepsis (4 and 24 h, respectively, after initiation of a standard infusion of live Pseudomonas aeruginosa). ⋯ Volume kinetic analysis was similar in all three protocols. In both nonseptic and septic sheep, infusion of 0.9% saline resulted in similar peak PVE and resolution of PVE over a 3-h interval and similar kinetic parameters. Contrary to clinical impressions and to our hypothesis, the distribution of 0.9% saline in this animal model was not changed by bacteremia produced by infusion of Pseudomonas aeruginosa.
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Anesthesia and analgesia · Sep 2005
Antiemetics of the 5-hydroxytryptamine 3A antagonist class inhibit muscle nicotinic acetylcholine receptors.
Antagonists of the serotonergic 5-hydroxytryptamine 3A receptor (5-HT(3A)R) and muscle nicotinic acetylcholine receptors (nAChR) are widely used in anesthesia practice. Both 5-HT(3A)R and nAChR are ligand-gated ion channels with known pharmacological overlap between some of their agonists and antagonists. We studied the actions of clinically used 5-HT(3A)R antagonist antiemetics and nondepolarizing muscle blockers on ionic currents elicited by the activation of mammalian 5-HT(3A)R and muscle nAChR, expressed in Xenopus laevis oocytes. ⋯ Conversely, ondansetron, dolasetron, and granisetron also reversibly inhibited nAChR currents in a dose-dependent manner with IC(50)s of 14.2, 7.8, and 4.4 microM for the adult nAChR and 16.0, 18.6, and 13.9 microM for the embryonic nAChR. Again, hydrodolasetron showed significantly (10 times) more inhibitory potency on the adult nAChR than the parent compound dolasetron. These results indicate that drugs that target specific ligand-gated ion channels may also affect other ion channel types.