Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2019
Observational StudyThe accuracy and trending ability of cardiac index measured by the fourth-generation FloTrac/Vigileo system™ and the Fick method in cardiac surgery patients.
To compare the accuracy and trending ability of the cardiac index (CI) measured by FloTrac/Vigileo™ (CIFT) or derived by the Fick equation (CIFick) using E-CAiOVX (enables continuous monitoring of oxygen consumption) with that measured by thermodilution (CITD) in patients with off-pump coronary artery bypass surgery. Twenty-two patients undergoing elective off-pump coronary artery bypass surgery were included. CIFT and CIFick were determined simultaneously at six time-points during off-pump coronary artery bypass surgery. ⋯ The concordance rate of four-quadrant plot analysis was 93.3% for CIFT and 66.7% for CIFick in datasets where CITD ≥ 2.4 L/min/m2 before and after phenylephrine administration were included. CIFT and CIFick had wide limits of agreement with CITD, and were below acceptable limits for tracking phenylephrine-induced CI changes. However, subgroup analysis showed improved accuracy and trending ability of CIFT when only points where CITD ≥ 2.4 L/min/m2 were included, while there was no improvement in CIFick accuracy or trending ability.
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J Clin Monit Comput · Oct 2019
Observational StudyMonitoring of pulse pressure variation using a new smartphone application (Capstesia) versus stroke volume variation using an uncalibrated pulse wave analysis monitor: a clinical decision making study during major abdominal surgery.
Pulse pressure variation (PPV) and stroke volume variation (SVV) can be used to assess fluid status in the operating room but usually require dedicated advanced hemodynamic monitors. Recently, a smartphone application (Capstesia™), which automatically calculates PPV from a picture of the invasive arterial pressure waveform from any monitor screen (PPVCAP), has been developed. The purpose of this study was to compare PPVCAP with SVV from an uncalibrated pulse wave analysis monitor (SVVPC). ⋯ PPVCAP and SVVPC would have resulted in completely opposite clinical decisions regarding fluid administration in 1% of the cases. In this clinical decision making study in patients undergoing major abdominal surgery, we observed a moderate agreement between PPVCAP and SVVPC with regard to categories used to guide fluid administration. Trial Registration: Clinical Trials.gov (NCT03137901).
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J Clin Monit Comput · Oct 2019
Observational StudyPhotoplethysmographic characterization of vascular tone mediated changes in arterial pressure: an observational study.
To determine whether a classification based on the contour of the photoplethysmography signal (PPGc) can detect changes in systolic arterial blood pressure (SAP) and vascular tone. Episodes of normotension (SAP 90-140 mmHg), hypertension (SAP > 140 mmHg) and hypotension (SAP < 90 mmHg) were analyzed in 15 cardiac surgery patients. SAP and two surrogates of the vascular tone, systemic vascular resistance (SVR) and vascular compliance (Cvasc = stroke volume/pulse pressure) were compared with PPGc. ⋯ The PPGc misclassified 7 out of the 190 episodes, presenting good accuracy (98.4% and 97.8%), sensitivity (100% and 94.9%) and specificity (97.9% and 99.2%) for detecting episodes of hypotension and hypertension, respectively. Changes in arterial pressure and vascular tone were closely related to the proposed classification based on PPG waveform. Clinical Trial Registration NTC02854852.
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J Clin Monit Comput · Oct 2019
LetterThe use of end-tidal argon to detect venous air embolism: foiled by "fake oxygen!"
Venous air-embolism (VAE) potentially catastrophic complication surgery. Based on previous data using changes in end-tidal nitrogen as an indicator of VAE, we surmised that changes in end-tidal argon (EtAr) may be an indicator of VAE. We sought to determine if a commercial mass-spectrometer (PCT Proline Analyzer 61700-8 Class 85, Ametek, Pittsburgh, PA 15238) could be used to detect changes in EtAr in an invitro model. ⋯ This is a USP-accepted contaminant, rendering this technology is insensitive for early, rapid detection of VAE. We assumed medical grade oxygen was pure and were surprised to learn otherwise. We want to share this likely largely unknown finding with the medical community.