Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2022
In-silico analysis of closed-loop vasopressor control of phenylephrine versus norepinephrine.
We have previously demonstrated in in-silico, pre-clinical animal models, and finally human clinical studies the ability of a novel closed-loop vasopressor titration system to manage norepinephrine infusion rates to keep mean arterial blood pressure in a very tight range, reduce hypotension time and severity, and reduce overtreatment. We hypothesized that the same controller could, with modification for pharmacologic differences, suitably titrate a lower-potency longer duration of action agent like phenylephrine. Using the same physiologic simulation model as was used previously for in-silico testing of our controller for norepinephrine, we first updated the model to include a new vasopressor agent modeled after phenylephrine. ⋯ The controller kept the simulated patients' MAP in target for 94% of management time in the simple scenarios and more than 85% of time in the most challenging scenarios. Varvel criteria were all under 1% error for expected pharmacologic responses and were consistent with those established for norepinephrine in our previous studies. The controller was able to acceptably titrate phenylephrine in this simulated patient model consistent with performance previously seen for norepinephrine after adjusting for the anticipated differences between the two agents.
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J Clin Monit Comput · Oct 2022
Positive end-expiratory pressure individualization guided by continuous end-expiratory lung volume monitoring during laparoscopic surgery.
To determine whether end-expiratory lung volume measured with volumetric capnography (EELVCO2) can individualize positive end-expiratory pressure (PEEP) setting during laparoscopic surgery. We studied patients undergoing laparoscopic surgery subjected to Fowler (F-group; n = 20) or Trendelenburg (T-group; n = 20) positions. EELVCO2 was measured at 0° supine (baseline), during capnoperitoneum (CP) at 0° supine, during CP with Fowler (head up + 20°) or Trendelenburg (head down - 30°) positions and after CP back to 0° supine. ⋯ Breath-by-breath noninvasive EELVCO2 detected changes in lung volume induced by capnoperitoneum and body position and was useful to individualize the level of PEEP during laparoscopy. Trial registry: Clinicaltrials.gov NCT03693352. Protocol started 1st October 2018.
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The current grading of facial nerve function is based on subjective impression with the established assessment scale of House and Brackmann (HB). Especially for research a more objective method is needed to lower the interobserver variability to a minimum. We developed a semi-automated grading system based on (facial) surface EMG-data measuring the facial nerve function of 28 patients with vestibular schwannoma surgery. ⋯ Lateralization indices were calculated and multivariant machine learning analysis was performed according to three scenarios [differentiation of normal (1) and slight (2) vs. impaired facial nerve function and classification of HB 1-3 (3)]. The calculated AUC for each scenario showed overall good differentiation capability with a median AUC of 0.72 for scenario 1, 0.91 for scenario 2 and multiclass AUC of 0.74 for scenario 3. This study approach using sEMG and machine learning shows feasibility regarding facial nerve grading in perioperative VS-surgery setting. sEMG may be a viable alternative to House Brackmann regarding objective evaluation of facial function especially for research purposes.
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J Clin Monit Comput · Oct 2022
Pressure-flow breath representation eases asynchrony identification in mechanically ventilated patients.
Breathing asynchronies are mismatches between the requests of mechanically ventilated subjects and the support provided by mechanical ventilators. The most widespread technique in identifying these pathological conditions is the visual analysis of the intra-tracheal pressure and flow time-trends. This work considers a recently introduced pressure-flow representation technique and investigates whether it can help nurses in the early detection of anomalies that can represent asynchronies. ⋯ The pressure-flow diagram significantly increases sensitivity and decreases the response time of early asynchrony detection performed by nurses. Moreover, the data suggest that operator experience does not affect the identification results. This outcome leads us to believe that, in emergency contexts with a shortage of nurses, intensive care nurses can be supplemented, for the sole identification of possible respiratory asynchronies, by inexperienced staff.
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J Clin Monit Comput · Oct 2022
Observational StudyContinuous transthoracic echocardiographic monitoring for changes in maternal cardiac hemodynamics during cesarean section under combined epidural-spinal anesthesia: a prospective, observational study.
The change in maternal hemodynamics during cesarean section has not been well studied. Continuous transthoracic echocardiography can monitor cardiac function continuously. This study aimed to evaluate the effectiveness of maternal hemodynamic parameters monitoring during cesarean section using continuous transthoracic echocardiography. ⋯ End-diastolic volume also increased significantly after delivery of the neonate, but end-systolic volume was unchanged. Following delivery of the neonate, fractional shortening increased till the end of the cesarean section while total peripheral resistance decreased significantly. In conclusion, continuous transthoracic echocardiographic monitoring revealed that there were significant changes in hemodynamic parameters during cesarean section after delivery of the newborn and placenta, which warranted further investigation.