Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2021
Non-contact thermography-based respiratory rate monitoring in a post-anesthetic care unit.
In patients at high risk of respiratory complications, pulse oximetry may not adequately detect hypoventilation events. Previous studies have proposed using thermography, which relies on infrared imaging, to measure respiratory rate (RR). These systems lack support from real-world feasibility testing for widespread acceptance. ⋯ Limits of agreement analysis revealed a bias of 1.3 and limits of agreement of 10.8 (95% confidence interval 9.07 to 12.5) and - 8.13 (- 6.41 to - 9.84) between direct measurements and bioimpedance, and a bias of -0.139 and limits of agreement of 2.65 (2.14 to 3.15) and - 2.92 (- 2.41 to 3.42) between direct measurements and thermography. Thermography allowed tracking of the manually measured RR in the post-anesthesia recovery unit without requiring patient contact. Additional work is required for image acquisition automation and nostril identification.
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J Clin Monit Comput · Dec 2021
Randomized Controlled TrialA mathematical model for predicting intracranial pressure based on noninvasively acquired PC-MRI parameters in communicating hydrocephalus.
To develop and validate a mathematical model for predicting intracranial pressure (ICP) noninvasively using phase-contrast cine MRI (PC-MRI). We performed a retrospective analysis of PC-MRI from patients with communicating hydrocephalus (n = 138). The patients were recruited from Shenzhen Second People's Hospital between November 2017 and April 2020, and randomly allocated into training (n = 97) and independent validation (n = 41) groups. ⋯ There was no significant difference in baseline demographic characteristics between the training and independent validation groups. The accuracy of the model for predicting ICP was 0.899 in the training cohort (n = 97) and 0.861 in the independent validation cohort (n = 41). We obtained an ICP-predicting model that showed excellent performance in the noninvasive diagnosis of clinically significant communicating hydrocephalus.
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J Clin Monit Comput · Dec 2021
Randomized Controlled TrialA beat-by-beat cardiovascular index, CARDEAN, to titrate opioid administration in the setting of orthopaedic surgery: a prospective randomized trial.
To determine whether a beat-by-beat cardiovascular index (CARDEAN: cardiovascular depth of analgesia, Alpha-2 Ltd, Lyon, France) reduces the incidence of tachycardia in ASA I-III patients undergoing orthopaedic surgery. A total of 76 patients were prospectively randomized into (1) a control group or (2) the CARDEAN group, in which the nurse anaesthetist was blinded to CARDEAN application. In addition to conventional signs, an external observer instructed the nurse anaesthetist to administer sufentanil 0.1 µg kg-1 when the CARDEAN crossed a threshold (≥ 60). ⋯ Data for 66 patients (27 with known hypertension) were analysed. In the CARDEAN group, (a) the dose of sufentanil was higher (control: 0.46 µg kg-1 100 min-1, CARDEAN: 0.57 µg kg-1 100 min-1, p = 0.016), (b) the incidence rates of tachycardia and untoward events were lower (respectively: - 44%; control: 2.52 events 100 min-1 [1.98-3.22]; CARDEAN: 1.42 [1.03-1.96], p = 0.005, hazard ratio: 0.56; movement, muscular contraction, or coughing: control: 0.74 events 100 min-1 [0.47-1.16]; CARDEAN: 0.31 [0.15-0.62], p = 0.038), and (c) extubation occurred more often in the operating room (control: 76.5%, CARDEAN: 97%, p = 0.016). CARDEAN-titrated opioid administration was associated with a higher dose of sufentanil, a reduction in tachycardia and earlier emergence in ASA I-III patients undergoing major orthopaedic surgery.
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J Clin Monit Comput · Dec 2021
Application of a benchtop colorimetric method for quantification of blood propofol levels.
Quantification of plasma propofol (2,6-diisopropylphenol) in the context of clinical anaesthesia is challenging because of the need for offline blood sample processing using specialised laboratory equipment and techniques. In this study we sought to refine a simple procedure using solid phase extraction and colorimetric analysis into a benchtop protocol for accurate blood propofol measurement. The colorimetric method based on the reaction of phenols (e.g. propofol) with Gibbs reagent was first tested in 10% methanol samples (n = 50) containing 0.5-6.0 µg/mL propofol. Subsequently, whole blood samples (n = 15) were spiked to known propofol concentrations and processed using reverse phase solid phase extraction (SPE) and colorimetric analysis. The standard deviation of the difference between known and measured propofol concentrations in the methanol samples was 0.11 µg/mL, with limits of agreement of - 0.21 to 0.22 µg/mL. For the blood-processed samples, the standard deviation of the difference between known and measured propofol concentrations was 0.09 µg/mL, with limits of agreement - 0.18 to 0.17 µg/mL. Quantification of plasma propofol with an error of less than 0.2 µg/mL is achievable with a simple and inexpensive benchtop method.
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J Clin Monit Comput · Dec 2021
Clinical TrialPostoperative continuous non-invasive cardiac output monitoring on the ward: a feasibility study.
Postoperative hypotension is common (occurring in one third of patients) and is associated with worse clinical outcomes. The LiDCO CNAP (continuous non-invasive arterial pressure) device measures haemodynamics but has not been widely adopted in ward environments. Improved early detection of hypotension by CNAP might guide interventions to improve clinical outcomes. ⋯ There were many episodes of hypotension unmasked through continuous monitoring. Based on the advanced haemodynamic data provided it is possible that the underlying cause of a third of postoperative hypotensive episodes is vasodilation rather than hypovolaemia. Trial registry number: NCT04010058 (ClinicalTrials.gov) Date of registration: 08/07/2019.