Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2015
Observational StudyProspective evaluation of regional oxygen saturation to estimate central venous saturation in sepsis.
Current treatment guidelines for sepsis claim an early goal-directed hemodynamic optimization including fluid resuscitation, use of vasopressors and inotropic agents. We investigated the correlation between the prominent treatment goal central venous saturation (ScvO2) and the frontal and the thenar regional oxygen saturation (rSO2) measured by near infrared spectroscopy. Secondary, we examined the value of ScvO2, lactate levels and rSO2 as surrogate markers of an impaired tissue oxygenation for outcome prediction in sepsis. ⋯ In the group with ScvO2 <70% and lactate levels <2.5 mmol/l no patients died during the observation period. Frontal rSO2 correlates with ScvO2 but both frontal and thenar rSO2 do not exactly discriminate between patients with high or low ScvO2 in sepsis. The combination of elevated lactate >2.5 mmol/l and ScvO2 >70 % is highly associated with poor outcome in ICU patients with sepsis, severe sepsis and septic shock.
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J Clin Monit Comput · Aug 2015
Effect of concurrent oxygen therapy on accuracy of forecasting imminent postoperative desaturation.
Episodic postoperative desaturation occurs predominantly from respiratory depression or airway obstruction. Monitor display of desaturation is typically delayed by over 30 s after these dynamic inciting events, due to perfusion delays, signal capture and averaging. Prediction of imminent critical desaturation could aid development of dynamic high-fidelity response systems that reduce or prevent the inciting event from occurring. ⋯ In conclusion, we report the use of autoregressive models to predict [Formula: see text] and forecast imminent critical desaturation events in the postoperative period with high degree of accuracy. These models reliably predict critical desaturation in patients receiving supplemental oxygen therapy. While high-fidelity prophylactic interventions that could modify these inciting events are in development, our current study offers proof of concept that the afferent limb of such a system can be modeled with a high degree of accuracy.
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J Clin Monit Comput · Aug 2015
Observational StudyReliability of a new 4th generation FloTrac algorithm to track cardiac output changes in patients receiving phenylephrine.
Phenylephrine is often used to treat intra-operative hypotension. Previous studies have shown that the FloTrac cardiac monitor may overestimate cardiac output (CO) changes following phenylephrine administration. A new algorithm (4th generation) has been developed to improve performance in this setting. ⋯ Agreement between FloTrac G3 and Nexfin was: 0.23 ± 1.19 l/min and concordance was 51.1%. In contrast, agreement between FloTrac G4 and Nexfin was: 0.19 ± 0.86 l/min and concordance was 87.2%. In conclusion, the pulse contour method of measuring CO, as implemented in FloTrac 4th generation algorithm, has significantly improved its ability to track the changes in CO induced by phenylephrine.
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J Clin Monit Comput · Aug 2015
Pulse transit time shows vascular changes caused by propofol in children.
Pulse transit time (PTT) is the time that it takes for the arterial pulse pressure wave to travel from the aortic valve to the periphery. It is a simple noninvasive technique for evaluating vascular changes. This study investigated the vascular changes by propofol during the induction of anesthesia in pediatric patients with the measuring of PTT. ⋯ The PTT after the peak changed variously; most of the patients showed no plateau; the PTT decreased progressively after the peak. The PTT after propofol administration prolonged in short time and rapidly recovered toward to the baseline values in pediatric patients. In conclusion, the baseline PTT in children is shorter comparing with adults and the vasodilatory effect of propofol on the vessels as described by the PTT was rapid and the recovery was faster, although the response to propofol was more varied than in adults.
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J Clin Monit Comput · Aug 2015
Comprehensive diagnosis of whole-body acid-base and fluid-electrolyte disorders using a mathematical model and whole-body base excess.
A mathematical model of whole-body acid-base and fluid-electrolyte balance was used to provide information leading to the diagnosis and fluid-therapy treatment in patients with complex acid-base disorders. Given a set of measured laboratory-chemistry values for a patient, a model of their unique, whole-body chemistry was created. This model predicted deficits or excesses in the masses of Na(+), K(+), Cl(-) and H2O as well as the plasma concentration of unknown or unmeasured species, such as ketoacids, in diabetes mellitus. ⋯ The results of this study showed the importance of a complete set of laboratory measurements to obtain sufficient accuracy of the quantitative diagnosis; having only a minimal set, just pH and PCO2, led to a large scatter in the predicted results. A computer module was created that would allow a clinician to achieve this diagnosis at the bedside. This new diagnostic approach should prove to be valuable in the treatment of the critically ill.