Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2021
Unexpected deposits in the anesthetic circuit: a possible cause of PEEP/Pmax valve malfunction.
PEEP is regulated by the internal PEEP/maximum peak inspiratory pressure limit (Pmax) valve. Malfunctioning of the PEEP/Pmax valve can result in the creation of unintentional or unstable PEEP, and a reduction of inspired tidal volume. Some of our Dräger Fabius® anesthesia machines were noted to exhibit changes in expiratory waveforms and unstable PEEP during general anesthesia. ⋯ The build-up of deposits occurred within a year after the previous regular inspection. Our troubleshooting process determined the issue with the PEEP/Pmax valve, which could go unnoticed because the valve is encased inside the breathing circuit, and requires disassembly for close inspection. Our findings should raise awareness regarding the importance of the preventive maintenance cycle as a safety precaution to keep the anesthetic circuit free of unexpected contamination.
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J Clin Monit Comput · Aug 2021
Observational StudyDoes ultrasonographic assessment of gastric antrum correlate with gastric residual volume in critically ill patients? A prospective observational study.
This study aimed to evaluate the relationship between ultrasonographic gastric antral measurements and aspirated gastric residual volume (GRV) in mechanically ventilated critically ill patients receiving enteral nutrition (EN). This prospective observational study included 56 enterally-fed critically ill patients in one-year period. All imaging procedures were done at 30-degree head-of-bed elevation and supine position on epigastric region of abdomen with 2.5-6 MHz convex-array probe just before routine GRV aspiration. ⋯ In Receiver operating characteristic (ROC) analysis of antral CSA ≥ 920 mm2 (mean + 1*SD) for estimating aspirated GRV, the area under the curve (AUC) was 0.848 (95% CI, 0.76 ~ 0.93) (p < 0.0001), and ROC analysis of antral CSA to discriminate aspirated GRV ≥ 250 mL showed a significant relation (AUC = 0.969, 95% CI 0.94 ~ 0.99, p < 0.0001). Ultrasonographic measurement of gastric antral CSA is an easy and reliable bedside procedure to estimate GRV in critically ill patients receiving EN in 30-degree head-of-bed elevation and supine position. Trial registration number: NCT04413474, date of registration: June 17, 2020, retrospectively registered.
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J Clin Monit Comput · Aug 2021
Assessment of spontaneous breathing during pressure controlled ventilation with superimposed spontaneous breathing using respiratory flow signal analysis.
Integrating spontaneous breathing into mechanical ventilation (MV) can speed up liberation from it and reduce its invasiveness. On the other hand, inadequate and asynchronous spontaneous breathing has the potential to aggravate lung injury. During use of airway-pressure-release-ventilation (APRV), the assisted breaths are difficult to measure. ⋯ In the mechanical subgroup the values for RRspont and MVspont the EVITA® showed higher values compared to Breath-Sep. We developed a computerized method for respiratory flow-curve based differentiation of breathing cycle components during mechanical ventilation with superimposed spontaneous breathing. Further studies in humans and optimizing of this technique is necessary to allow for real-time use at the bedside.
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J Clin Monit Comput · Aug 2021
Randomized Controlled TrialComparison of haemodynamic- and electroencephalographic-monitored effects evoked by four combinations of effect-site concentrations of propofol and remifentanil, yielding a predicted tolerance to laryngoscopy of 90.
This prospective study evaluates haemodynamic and electroencephalographic effects observed when administering four combinations of effect-site concentrations of propofol (CePROP) and remifentanil (CeREMI), all yielding a single predicted probability of tolerance of laryngoscopy of 90% (PTOL = 90%) according to the Bouillon interaction model. We aimed to identify combinations of CePROP and CeREMI along a single isobole of PTOL that result in favourable hypnotic and haemodynamic conditions. This knowledge could be of advantage in the development of drug advisory monitoring technology. 80 patients (18-90 years of age, ASA I-III) were randomized into four groups and titrated towards CePROP (Schnider model, ug⋅ml-1) and CeREMI (Minto model, ng⋅ml-1) of respectively 8.6 and 1, 5.9 and 2, 3.6 and 4 and 2.0 and 8. ⋯ This study provides clinical insight on the haemodynamic and hypnotic consequences, when a model based predicted PTOL is used as a target for combined effect-site controlled target- controlled infusion of propofol and remifentanil. Heart rate and bispectral index were significantly different between groups despite a theoretical equipotency for PTOL, suggesting that each component of the anaesthetic state (immobility, analgesia, and hypnotic drug effect) should be considered as independent neurophysiological and pharmacological phenomena. However, claims of (in)accuracy of the predicted PTOL must be considered preliminary because larger numbers of observations are required for that goal.