Journal of clinical monitoring and computing
-
J Clin Monit Comput · Apr 2002
Comparative StudyComparison of endotracheal tube and hookwire electrodes for monitoring the vagus nerve.
Monitoring the vagus nerve and the recurrent laryngeal nerve during surgical procedures may reduce the probability of significant nerve injury. As such, a number of methods to monitor these nerves have been devised including placing electrodes directly into the vocal cords or recording from surface electrodes. In direct comparison, monitoring the identical muscles, bipolar hookwire electrodes displayed approximately one order of magnitude greater amplitude, of both spontaneously occurring and evoked electrical activity than double wire endotracheal tube electrodes. The enhanced sensitivity of the hookwire electrodes, despite the technical difficulties with placement, suggests their use when maximum sensitivity is required.
-
J Clin Monit Comput · Apr 2002
A prototype device for standardized calibration of pulse oximeters II.
There is no commonly accepted in vivo calibration method for pulse oximeters available up to now. On the basis of a prototype device for the calibration of pulse oximeters which was introduced recently, a second approach based on the same concept was tackled in order to design a reliable method for standardized calibration of pulse oximeters. ⋯ Compared to the first prototype the current version is simpler and less expensive in production. Many of previously existing problems are solved and the applicability to a large variety of pulse oximeters and sensors is given. The novel concept for the calibration of pulse oximeters is a tool for assessing the performance of pulse oximeters.
-
J Clin Monit Comput · Apr 2002
Case ReportsCompartment syndrome of the arm: a complication of noninvasive blood pressure monitoring during thrombolytic therapy for myocardial infarction.
We report a rare case of tricep compartment syndrome caused by a hematoma which resulted from noninvasive blood pressure monitoring (NIBPM) during thrombolytic therapy. Clinicians administering thrombolytic agents should be aware of the risk of bleeding and compartment syndrome at the site of NIBPM. Appropriate preventative measures should be instituted when using automated pneumatic cuffs. An understanding of the pathophysiology and clinical presentation of an arm compartment syndrome will allow for prompt diagnosis and surgical treatment.
-
J Clin Monit Comput · Apr 2002
Real-time pulse oximetry artifact annotation on computerized anaesthetic records.
Adoption of computerised anaesthesia record keeping systems has been limited by the concern that they record artifactual data and accurate data indiscriminately. Data resulting from artifacts does not reflect the patient's true condition and presents a problem in later analysis of the record, with associated medico-legal implications. This study developed an algorithm to automatically annotate pulse oximetry artifacts and sought to evaluate the algorithm's accuracy in routine surgical procedures. ⋯ The real-time artifact detection algorithm developed in this study was more accurate than anaesthetists who post-operatively reviewed records produced by an existing computerised anaesthesia record keeping system. Algorithms have the potential to more accurately identify and annotate artifacts on computerised anaesthetic records, assisting clinicians to more correctly interpret abnormal data.
-
J Clin Monit Comput · Apr 2002
Performance of a real-time dicrotic notch detection and prediction algorithm in arrhythmic human aortic pressure signals.
A novel algorithm for real-time detection and prediction of the dicrotic notch from aortic pressure waves was evaluated in arrhythmic aortic pressure signals from heart failure patients. A simplified model of the arterial tree was used to calculate real-time aortic flow from aortic pressure. The dicrotic notch was detected at the first negative dip from the calculated flow, prediction of the notch was performed using a percentage of the decreasing flow. ⋯ Prediction of the dicrotic notch was tested at 40%, 20%, and 0% of the decreasing calculated aortic flow. The mean time-delays to the notch were 68 +/- 14 ms, 55 +/- 12 ms, and 43 +/- 8 ms, respectively. Given these small variability, intra-beat prediction of the dicrotic notch may be used for real-time intra-aortic balloon counterpulsation inflation timing.