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 perfusion value predicts eye opening after sevoflurane anaesthesia: an explorative study.
The variables measured in modern pulse oximetry apparatuses include a graphical pulse curve and a specified perfusion value (PV) that could be a sensitive marker for detecting differences in sympathetic activity. We hypothesized that there is a correlation between a reduction of PV and the time to eye opening after general anaesthesia. The objective was to investigate whether PV can predict eye opening after sevoflurane anaesthesia. ⋯ PV values were lower before anaesthesia and at eye opening compared to at 15 min after induction and at end of surgery (P < 0.05). The reduction of PV between end of surgery and eye opening was 0.76. We conclude that the pulse oximeter PV could be a useful variable to assess the timing of recovery, in terms of eye opening after a general anaesthesia.
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J Clin Monit Comput · Aug 2015
Observational StudyAgreement between stroke volume measured by oesophageal Doppler and uncalibrated pulse contour analysis during fluid loads in severe aortic stenosis.
The purpose of this analysis was to study agreement and trending of stroke volume measured by oesophageal Doppler and 3rd generation Vigileo during fluid loads in patients with severe aortic stenosis. Observational study in 32 patients (30 analyzed) scheduled for aortic valve replacement due to severe aortic stenosis. After induction of anesthesia and before start of surgery, hemodynamic registrations for 1 min were obtained before and after a fluid load. ⋯ Absolute values of SVOD and SVVig agreed poorly, but changes were highly concordant during fluid loads in aortic stenosis patients. The angular agreement indicated acceptable trending. The two measurement methods are not interchangeable in patients with aortic stenosis.