Journal of clinical monitoring and computing
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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.
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J Clin Monit Comput · Oct 2019
Reliability of effective arterial elastance using peripheral arterial pressure as surrogate for left ventricular end-systolic pressure.
To compare the effective arterial elastance (Ea) obtained from the arterial pressure with Ea calculated from left-ventricular (LV) pressure-volume analysis. Experimental study. LV pressure-volume data was obtained with a conductance catheter and arterial pressures were measured via a fluid-filled catheter placed in the proximal aorta, femoral and radial arteries. ⋯ When Ea was compared with estimates using MAP, the relationship was r2 = 0.95, 0.96 and 0.95 for Eaao_MAP, Eafem_MAP and Earad_MAP, respectively; with a bias and LOA: 0.05 ± 0.11, 0.06 ± 0.11, 0.06 ± 0.11 mmHg ml-1, respectively. LV ESP can be estimated from the arterial pressure. Provided that the SV measurement is reliable, the ratio MAP/SV provides a robust Ea surrogate over a wide range of hemodynamic conditions and is interchangeably in any peripheral artery, so it should be recommended as an arterial estimate of Ea in further research.
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J Clin Monit Comput · Oct 2019
Multicenter Study Comparative Study Clinical Trial Observational StudyMindray 3-directional NMT Module (a new generation "Tri-axial" neuromuscular monitor) versus the Relaxometer mechanomyograph and versus the TOF-Watch SX acceleromyograph.
Recently introduced Mindray "3-directional" neuromuscular transmission transducer (NMT, Shenzhen, China) acceleromyograph) claim to monitor thumb movement in 3 different directions. We compared NMT with the gold standard Relaxometer® mechanomyograph (MMG, Groningen University, Netherlands) in Study-1 and with TOF-Watch SX™ (WTCH) acceleromyograph from which it was developed in Study-2. We used first twitch (T1%) and train-of-four (TOF) ratio rocuronium 0.6 mg kg-1 neuromuscular block to evaluate NMT diagnostic accuracy in indicating 3 clinically relevant time points namely; MMG T1 5% (95% twitch depression) for tracheal intubation, MMG T1 25% for repeat neuromuscular blocking agents (NMBAs) administration, and MMG 0.9 TOF ratio full neuromuscular block recovery. ⋯ NMT could not efficaciously detect MMG time for tracheal intubation; NMBAs repeat dose administration or full neuromuscular block recovery. Data from NMT cannot be used interchangeably with MMG. Our study revealed that NMT Tri-axial acceleromyography seems to offer no advantage over the MMG gold standard or the classic Mono-axial TOF-Watch SX monitor.
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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).