Aki Mäkivirta

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Postoperative monitoring of cardiac operated patients requires appropriately functioning monitor alarms as well as intensive nursing activity. The limit alarms can be used for detection of life-threatening situations and monitoring of physiological changes in the patient's state. We studied the significance and the frequency of audible alarms during the(More)
We studied the effects of removing brief variations in the monitoring data on the quality of limit alarms during the postoperative haemodynamic monitoring of cardiac patients. The variations were removed by median filtering. The false alarm frequency was reduced by more than two-thirds compared with a typical patient monitor. We designed and clinically(More)
IP networks allow constructing versatile device configurations for multimedia streaming. However, the stochastic nature of the packet-switched data transmission may complicate IP-based implementations of some conventional applications such as analog wired transmission of synchronized multi-channel audio. This paper introduces a multimedia streaming system(More)
A knowledge-based alarm system for intensive care monitoring was designed, built, tested on-line, and evaluated. The system is a functional prototype of a highly specific patient monitor providing alarms on hypovolemia, hyperdynamic state, left ventricular failure and hypoventilation. These intelligent alarm functions aim to maintain the quality of patient(More)
To survey the routine use of bedside multivariable monitors in monitoring cardiac postoperative patients, 23 experienced anesthesiologists and cardiac surgeons were first asked to list which variables and what limit alarms they used. Then they defined to what extent the variables' values were allowed to deviate before therapeutic actions were needed.(More)
An intelligent alarm system for the postoperative monitoring of cardiac surgery patients, which did not require any manual data entries, was tested in two phases. A clinician monitored at bedside the patients' recovery and verified clinically abnormal physiological states. After the first test with ten patients, the system's rulebase was upgraded and then(More)
Objective. Our objective was to study the distribution of invasively measured hemodynamic data to enhance the reliability of patient monitor alarm systems.Methods. Monitoring data were collected, preprocessed off-line, and analyzed in 10 postcardiac surgery patients. The data were studied statistically to estimate the probability distributions, the(More)
The development of intelligent alarm systems for intensive care benefits from the transformation of data from a quantitative to a qualitative mode. We constructed a computerized algorithm for the symbolization of on-line monitoring data of heart rate, systemic arterial, pulmonary arterial and central venous pressures, as well as central and peripheral(More)