Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2016
Observational StudyNon-invasive measurements of pulse pressure variation and stroke volume variation in anesthetized patients using the Nexfin blood pressure monitor.
Nexfin beat-to-beat arterial blood pressure monitoring enables continuous assessment of hemodynamic indices like cardiac index (CI), pulse pressure variation (PPV) and stroke volume variation (SVV) in the perioperative setting. In this study we investigated whether Nexfin adequately reflects alterations in these hemodynamic parameters during a provoked fluid shift in anesthetized and mechanically ventilated patients. The study included 54 patients undergoing non-thoracic surgery with positive pressure mechanical ventilation. ⋯ The median bias between PPV and SVV was different for patients younger [-1.5 % (-3 to 0)] or older [+2 % (0-4.75)] than 55 years (P < 0.001), while there were no gender differences in the bias between PPV and SVV. The Nexfin monitor adequately reflects alterations in PPV and SVV during a provoked fluid shift, but the level of agreement between PPV and SVV was low. The SVV tended to be superior over PPV or Eadyn in predicting fluid responsiveness in our population.
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J Clin Monit Comput · Oct 2016
Changes in cerebral oxygen saturation during transcatheter aortic valve replacement.
Cerebral oxygen saturation (rSO2) is a non-invasive monitor used to monitor cerebral oxygen balance and perfusion. Decreases in rSO2 >20 % from baseline have been associated with cerebral ischemia and increased perioperative morbidity. During transcatheter aortic valve replacement (TAVR), hemodynamic manipulation with ventricular pacing up to 180 beats per minute is necessary for valve deployment. ⋯ Furthermore, baseline rSO2 in this population was at the lower limit of the published normal range. Significant cerebral desaturation during valve deployment may potentially be limited by maximizing rSO2 after anesthetic induction. Future studies should attempt to correlate recovery in rSO2 with recovery of hemodynamics and cardiac function, provide detailed neurological assessments pre and post procedure, determine the most effective method of maximizing rSO2 prior to hemodynamic manipulation, and provide the most rapid method of recovery of rSO2 following valve deployment.
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J Clin Monit Comput · Oct 2016
Evaluation of a fiber-optic technique for recording intramuscular pressure in the human leg.
To evaluate a forward-sensing fiber-optic pressure technique for recording of intramuscular pressure (IMP) in the human leg and investigate factors that may influence IMP measurements used in diagnosing compartment syndromes. IMP in the tibialis anterior muscle was recorded simultaneously by a fiber-optic technique and needle-injection technique in 12 legs of 7 healthy subjects. Both measurement catheters were placed in parallel with the muscle fibers to the same depth, as verified by sonography. ⋯ The fiber-optic technique may be used for IMP measurements in a muscle with both normal and abnormally elevated IMP. It has good dynamic properties allowing for measurement of IMP oscillations. Saline injection used with needle-injection systems to ensure catheter patency compromises IMP readings at least one minute after injection.
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J Clin Monit Comput · Oct 2016
Continuous-wave near-infrared spectroscopy is not related to brain tissue oxygen tension.
Near-infrared spectroscopy (NIRS) has gained acceptance for cerebral monitoring, especially during cardiac surgery, though there are few data showing its validity. We therefore aimed to correlate invasive brain tissue oxygen measurements (PtiO2) with the corresponding NIRS-values (regional oxygen saturation, rSO2). We also studied whether NIRS was able to detect ischemic events, defined as a PtiO2-value of <15 mmHg. ⋯ Continuous-wave-NIRS was unable to reliably detect ischemic cerebral episodes, defined as a PtiO2 value <15 mmHg. Displayed NIRS-values did not correlate with invasively measured PtiO2-values. CW-NIRS should not be used for the detection of cerebral ischemia.