Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2021
LetterAnti-decubitus bed mattress may interfere with cerebrovascular pressure reactivity measures due to induced ICP and ABP cyclic peaks.
Severe traumatic brain injury (TBI) patients are monitored with continuous arterial blood pressure (ABP) and intracranial pressure (ICP). The pressure reactivity index (PRx) is a frequently used correlation coefficient between ABP and ICP to inform clinicians at the bedside about trends in global cerebrovascular pressure regulation status. We present an unexpected influence of cyclic anti-decubitus mattress inflations and deflations on invasive ICP, ABP and PRx calculations in our TBI patients. ⋯ In our database, 23% (9/39) of the patients show recurrent peaks in the monitoring signals. We hypothesize that these peaks are caused by (a combination) of hydrostatic change, local (cervical) compression and/or incorrect sensor zeroing due to positional changes induced by the anti-decubitus mattress. This warrants further investigation by the manufacturer and exploration of data filters.
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J Clin Monit Comput · Apr 2021
Continuous and entirely non-invasive method for cerebrovascular reactivity assessment: technique and implications.
Continuous cerebrovascular reactivity assessment in traumatic brain injury (TBI) has been limited by the need for invasive monitoring of either cerebral physiology or arterial blood pressure (ABP). This restricts the application of continuous measures to the acute phase of care, typically in the intensive care unit. It remains unknown if ongoing impairment of cerebrovascular reactivity occurs in the subacute and long-term phase, and if it drives ongoing morbidity in TBI. ⋯ Recent advances in continuous high-frequency non-invasive ABP measurement, combined with NIRS or rTCD, can be employed to derive continuous and entirely non-invasive cerebrovascular reactivity metrics. Such non-invasive measures can be obtained during any aspect of patient care post-TBI, and even during outpatient follow-up, avoiding classical intermittent techniques and costly neuroimaging based metrics obtained only at specialized centers. This combination of technology and signal analytic techniques creates avenues for future investigation of the long-term consequences of cerebrovascular reactivity, integrating high-frequency non-invasive cerebral physiology, neuroimaging, proteomics and clinical phenotype at various stages post-injury.
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J Clin Monit Comput · Apr 2021
Observational StudyOscillometric versus invasive blood pressure measurement in patients with shock: a prospective observational study in the emergency department.
In emergency medicine, blood pressure is often measured by an oscillometric device using an upper arm cuff. However, measurement accuracy of this technique in patients suffering from hypotensive shock has not been sufficiently evaluated. We designed a prospective observational study investigating the accuracy of an oscillometric device in hypotensive patients admitted to the resuscitation area of the emergency department. ⋯ In 64% of readings, values obtained by the upper arm cuff were not able to detect hypotension. Oscillometric blood pressure measurement is not able to reliably detect hypotension in emergency patients. Therefore, direct measurement of blood pressure should be established as soon as possible in patients suffering from shock.
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J Clin Monit Comput · Apr 2021
Performance of a closed-loop glucose control system, comprising a continuous glucose monitoring system and an AI-based controller in swine during severe hypo- and hyperglycemic provocations.
Intensive care unit (ICU) patients develop stress induced insulin resistance causing hyperglycemia, large glucose variability and hypoglycemia. These glucose metrics have all been associated with increased rates of morbidity and mortality. The only way to achieve safe glucose control at a lower glucose range (e.g., 4.4-6.6 mmol/L) will be through use of an autonomous closed loop glucose control system (artificial pancreas). ⋯ The total percent time within tight glucose control range, 4.4-6.6 mmol/L, was 32.8% (32.4-47.1) for Controls and 55.4% (52.9-59.4) for Treated (p < 0.034). Data are median and quartiles. The artificial pancreas system abolished severe hypoglycemia and outperformed the experienced ICU physician in avoiding clinically significant hypoglycemic excursions.
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J Clin Monit Comput · Apr 2021
An effective pressure-flow characterization of respiratory asynchronies in mechanical ventilation.
Ineffective effort during expiration (IEE) occurs when there is a mismatch between the demand of a mechanically ventilated patient and the support delivered by a Mechanical ventilator during the expiration. This work presents a pressure-flow characterization for respiratory asynchronies and validates a machine-learning method, based on the presented characterization, to identify IEEs. 1500 breaths produced by 8 mechanically-ventilated patients were considered: 500 of them were included into the training set and the remaining 1000 into the test set. Each of them was evaluated by 3 experts and classified as either normal, artefact, or containing inspiratory, expiratory, or cycling-off asynchronies. ⋯ The software classified IEEs with sensitivity 0.904, specificity 0.995, accuracy 0.983, positive and negative predictive value 0.963 and 0.986, respectively. The Cohen's kappa is 0.983 (with 95% confidence interval (CI): [0.884, 0.962]). The pressure-flow characterization of respiratory cycles and the monitoring technique proposed in this work automatically identified IEEs in real-time in close agreement with the experts.