Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2009
Case ReportsEarly non invasive detection of hypercarbia in two cardiac surgical patients.
The availability of transcutaneous monitors has provided a means of non invasive assessment of CO(2) tension and a trend of the ventilation status commonly in infants and neonates. The authors describe two cases of hypercapnia diagnosed early in adults by the non invasive transcutaneous measurement of carbon dioxide (tcpCO(2)) using TINA TCM4 in postoperative cardiac surgical patients who were mechanically ventilated. Curiously, this increase in tcpCO(2) levels was associated with a false increase in the tcpO(2) values though no changes in the ventilatory parameters to increase oxygenation were made. The probable mechanism of the increase in tcpO(2) levels with hypercarbia is discussed.
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J Clin Monit Comput · Feb 2009
Technical performance and reflection capacity of the anaesthetic conserving device--a bench study with isoflurane and sevoflurane.
The anaesthetic conserving device (AnaConDa), Sedana Medical, Sundbyberg, Sweden) facilitates administration of isoflurane or sevoflurane by liquid infusion. An anaesthetic reflector inside the device conserves exhaled anaesthetic and re-supplies it during inspiration. In this bench study, we examined the influence of infusion rates and ventilatory settings on the resulting anaesthetic concentrations on patient (C(pat)) and ventilator side of the reflector (C(loss)) to describe its technical performance. ⋯ The triple product minute volume times R(C) times C(pat) describes anaesthetic losses through the reflector. It can easily be calculated as long as the 10 ml reflection capacity is not exceeded and thus R(C) is constant. Increased minute ventilation necessitates increasing the IR to keep C(pat) constant. When using large V(T) and high C(pat) "spill over" occurs. This effect offers some protection against an inadvertent overdose.
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J Clin Monit Comput · Feb 2009
Specificity improvement for network distributed physiologic alarms based on a simple deterministic reactive intelligent agent in the critical care environment.
Automated physiologic alarms are available in most commercial physiologic monitors. However, due to the variability of data coming from the physiologic sensors describing the state of patients, false positive alarms frequently occur. Each alarm requires review and documentation, which consumes clinicians' time, may reduce patient safety through 'alert fatigue' and makes automated physician paging infeasible. ⋯ Alarms generated by patient monitors, the intelligent agent and alerts documented on patient flow sheets were compared. Significant improvements in the specificity of the physiologic alarms based on systolic and mean blood pressure was found on average to be 99% and 88% respectively. Even through significant improvements were noted based on this algorithm much work still needs to be done to ensure the sensitivity of alarms and methods to handle spurious sensor data due to patient or sensor movement and other influences.