Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Randomized Controlled Trial Clinical TrialSpecific elements of a new hemodynamics display improves the performance of anesthesiologists.
We tested the hypothesis that a monitoring display proposed by Blike et al. improves the performance of anesthesiologists. We measured the performance of anesthesiologists using the new display and compared it to their performance with a traditional display. We studied three different displays on how they affected recognition and differentiation of five etiologies of shock-anaphylaxis, bradycardia, hypovolemia, ischemia and pulmonary embolus. ⋯ The new display with "emergent features" can improve the diagnostic performance of clinicians.
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J Clin Monit Comput · Jan 2000
Computer assisted physiologic monitoring and stability assessment in vascular surgical patients undergoing general anesthesia--preliminary data.
Physiologic monitors present an influx of numerical data that can be overwhelming to the clinician. We combined several parameters in an effort to reduce the amount of information that must be continuously monitored including oxyhemoglobin saturation by pulse oximetry, end-tidal CO2 concentration, arterial blood pressure, and heart rate into an integrated measure--the health stability magnitude (HSM). The HSM is computed for a predetermined basal period, the reference HSM (RHSM), and recalculated continuously for comparison with the baseline value. In this study we present the HSM concept and examine changes in the HSM during abdominal aortic aneurysm surgery. ⋯ The correlation between HSM and dHSM depicts changes in multiple monitored parameters that can be viewed using a single graphical representation. Projection of individual cases on the contour diagram may help the clinician to distinguish relative intraoperative stability from important events. Data reduction in this manner may guide clinical decision-making in response to unanticipated or unrecognized events.
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J Clin Monit Comput · Jan 2000
ReviewHRCT imaging of airway responsiveness: effects of anesthetics.
The noninvasive imaging method, high resolution computed tomography (HRCT), has been developed in animal models and applied to humans with obstructive lung disease for assessing regional and individual airway responsiveness. The ability to directly view airway responses during provocations such as tracheal intubation in an asthmatic could greatly enhance our understanding and treatment of airway hyperresponsiveness. HRCT uses increased kilovoltage peak (kVp) and milliamperage (mAs) settings, thin slices, high spacial frequency reconstruction algorithms, and small fields of view to resolve structures as small as 200 microm. ⋯ HRCT allows direct in vivo measurement of airway responsiveness to pharmacological and physiological stress that induces bronchoconstriction or bronchodilation. Using HRCT, we are able to measure airway dilation at baseline airway tone with inhalation anesthetics, differentiate the bronchodilating properties of inhalational agents in airways with tone, assess bronchodilating agents commonly used as premedications prior to anesthesia, and measure airway heterogeneity at baseline tone and their response to a variety of stimuli. This ability of HRCT to measure airway caliber and response heterogeneity in vivo noninvasively will dramatically improve our understanding of pulmonary physiology in general and the effects of anesthetics on the airways specifically.
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J Clin Monit Comput · Jan 2000
ReviewEffects of high thoracic epidural anesthesia and local anesthetics on bronchial hyperreactivity.
Bronchial hyperreactivity can cause life threatening bronchospasm after airway irritation. Therefore, endotracheal intubation is avoided in asthmatics when feasible. High thoracic epidural anesthesia can be used to avoid endotracheal intubation and offers less postoperative pulmonary complications when compared to systemic postoperative analgesia. ⋯ The attenuation of bronchial hyperreactivity can be shown as a dose dependent effect of lidocaine and bupivacaine. The intravenous effect of lidocaine is comparable to the effect of a moderate dose of salbutamol and leads to an additive effect when both drugs are used in combination. Overall, high thoracic epidural anesthesia can be used safely in patients with bronchial hyperreactivity and intravenous administration of lidocaine (1.5-2.0 mg x kg(-1)) can be used as a prophylactic treatment prior to airway instrumentation.
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J Clin Monit Comput · Jan 2000
Atypical "tails-up" capnograph due to breach in the sampling tube of side-stream capnometer.
An atypical "tails-up" capnograph pattern was noticed in a patient during the use of an accidentally crushed sampling tube with a slit-like hole. We investigated the mechanics involved in the observed capnograph pattern. ⋯ During IPPV, pressure in the breathing circuit is lower during exhalation, thus allowing air to enter through the slit-like hole in the sampling tube causing erroneously low ETCO2 and expiratory sevoflurane. With inspiration, positive pressure in the breathing circuit, transmitted to the sampling tube, prevents air admixture and the upsurge in CO2 is displayed giving the capnograph an atypical "tails-up" appearance. During spontaneous breathing, since pressure in the breathing circuit barely becomes positive during exhalation and is negative during inspiration, air mixes with the sampled gas during both phases and so the capnograph shape was normal but with lower values for ETCO2, insp./exp. sevoflurane, and nitrous oxide levels. If undiagnosed, this defect in the sampling tube can lead to significant errors in the measurement of inspired and expired gas concentrations.