Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2020
Validation of an automated system for detecting ineffective triggering asynchronies during mechanical ventilation: a retrospective study.
We compare the sensitivity and specificity of clinician visual waveform analysis against an automated system's waveform analysis in detecting ineffective triggering in mechanically ventilated intensive care unit patients when compared against a reference label set based upon analysis of respiratory muscle activity. Electrical activity of the diaphragm or esophageal/transdiaphragmatic pressure waveforms were available to a single clinician for the generation of a reference label set indicating the ground truth, that is, presence or absence of ineffective triggering, on a breath-by-breath basis. Pressure and flow versus time tracings were made available to (i) a group of three clinicians; and (ii) the automated Syncron-E™ system capable of detecting patient-ventilator asynchrony in real-time, in order to obtain breath-by-breath labels indicating the presence or absence of ineffective triggering. ⋯ Specificity for clinicians and the automated system were high (99.3% for clinician and 98.5% for the automated system). The automated system had a significantly higher sensitivity (83.2%) compared to clinicians (41.1%). Ineffective triggering detected by the automated system, which has access only to airway pressure and flow versus time tracings, is in substantial agreement with a reference detection derived from analysis of invasively measured patient effort waveforms.
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J Clin Monit Comput · Dec 2020
Multicenter StudyEffects of a standardized distraction on caregivers' perceptive performance with avatar-based and conventional patient monitoring: a multicenter comparative study.
Patient monitoring requires constant attention and may be particularly vulnerable to distractions, which frequently occur during perioperative work. In this study, we compared anesthesia providers' perceptive performance and perceived workload under distraction for conventional and avatar-based monitoring, a situation awareness-based technology that displays patient status as an animated patient model. In this prospective, multicenter study with a within-subject design, 38 participants evaluated scenarios of 3- and 10-s durations using conventional and avatar-based monitoring, under standardized distraction in the form of a simple calculation task. ⋯ Participants rated perceived workload lower under distraction with the avatar in the 3-s scenario: 65 (IQR 40-79) vs. 75 (IQR 51-88), p = 0.007, MoD: 9 (95% CI 3 to 15), and in the 10-s scenario: 68 (IQR 50-80) vs. 75 (IQR 65-86), p = 0.019, MoD: 10 (95% CI 2 to 18). Avatar-based monitoring improved anesthesia providers' perceptive performance under distraction and reduced perceived workload. This technology could help to improve caregivers' situation awareness, especially in high-workload situations.
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J Clin Monit Comput · Dec 2020
Do changes in perfusion index reflect changes in stroke volume during preload-modifying manoeuvres?
Changes in stroke volume (deltaSV) induced by a lung recruitment manoeuvre (LRM) have been shown to accurately predict fluid responsiveness during protective mechanical ventilation. Cardiac output monitors are used in a limited number of surgical patients. In contrast, all patients are monitored with a pulse oximeter, that may enable the continuous monitoring of a peripheral perfusion index (PI). ⋯ A deltaPI ≥ 26% predicted a deltaSV > 30% with a sensitivity of 83% and a specificity of 78% (AUC = 0.84, 95%CI 0.71-0.93). 24 patients experienced a deltaSV > 30% and subsequently received fluid. Fluid loads induced a 16% increase in SV and a 17% increase in PI, but fluid-induced deltaPI and deltaSV were weakly correlated (r2 = 0.19). In neurosurgical patients, we conclude that deltaPI may be used as a surrogate for deltaSV during LRMs but not during fluid loading.
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J Clin Monit Comput · Dec 2020
Observational StudySurrogate indices of aortic peak systolic velocity variation to monitor fluid responsiveness in pediatric non-cardiac surgery: a prospective observational study.
Aortic peak systolic velocity variation (ΔVpeakAo) is a reliable dynamic indicator of preload in mechanically ventilated children. However, easily measurable alternative parameters like carotid peak systolic velocity variation (ΔVpeakCa) and suprasternal peak systolic velocity variation (ΔVpeakSs) are not well evaluated in children. The aim of the study was to find correlation between ΔVpeakCa and ΔVpeakSs to ΔVpeakAo, as potential surrogate markers of fluid responsiveness. 52 children, 1-12 years old, undergoing major non-cardiac surgeries under general endotracheal anaesthesia were recruited for this single-centre prospective observational study. ΔVpeakAo, ΔVpeakCa and ΔVpeakSs were measured by pulsed wave Doppler in appropriate windows, measuring maximum and minimum peak flow velocity over a single respiratory cycle. ⋯ Bland-Altman analysis showed minimal bias of 1.86 percentage points with limits of agreement of 11.21 to - 7.49 (ΔVpeakAo and ΔVpeakSs) and 3.93 percentage points with limits of agreement of 14.04 to - 6.18 (ΔVpeakAo and ΔVpeakCa). ΔVpeakSs and ΔVpeakCa also showed good discrimination to predict ΔVpeakAo (lying in previously validated fluid responsive zones) with sensitivities and specificities of 82.25% and 85% with cut-off of 11% for ΔVpeakSs, and 88.52% and 70% with cut-off of 8.6% for ΔVpeakCa. Carotid peak systolic velocity variation (ΔVpeakCa) and suprasternal peak systolic velocity variation (ΔVpeakCa) can be potential surrogate markers for Aortic peak systolic velocity variation (ΔVpeakAo) in assessing fluid responsiveness in mechanically ventilated children. Study registration: Clinicaltrials.gov ID NCT03155555.
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J Clin Monit Comput · Dec 2020
Observational StudyThe ability of perfusion index to detect segmental ulnar nerve sparing after supraclavicular nerve block.
Supraclavicular nerve block (SCB) is a commonly used regional block for upper extremity surgery. The most common form of failure of SCB is ulnar segmental sparing. We aimed to evaluate the accuracy of perfusion index (PI) in early detection of segmental sparing of the ulnar component of SCB. ⋯ An increase of 71% in PI at the little finger 5 min after SCB could accurately rule out ulnar sparing. Clinical trial identifier NCT03880201. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT03880201?term=NCT03880201&draw=2&rank=1 .