Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2020
Event-triggered averaging of electrical impedance tomography (EIT) respiratory waveforms as compared to low-pass filtering for removal of cardiac related impedance changes.
Electrical impedance tomography (EIT) is used for bedside ventilation monitoring; cardiac related impedance changes represent a source of noise superimposed on the ventilation signal, commonly removed by low-pass filtering (LPF). We investigated if an alternative approach, based on an event-triggered averaging (ETA) process, is more effective at preserving the actual ventilation waveform. Ten paralyzed patients undergoing volume-controlled ventilation were studied; 30 breaths for each patient were identified to compare LPF and ETA. ⋯ Both for global and regional waveforms, minimum and maximum EIT slopes were steeper by ETA as compared to LPF (average difference respectively - 57 ± 60 mL/s and 144 ± 96 mL/s for global signal, p < 0.05); ventilator inspiratory peak airflow correlated with maximum slope measured by ETA (r = 0.902, p < 0.001), but not LPF (p = 0.319). Beginning of inspiration identified on the ventilator waveform and on the global EIT signal by ETA occurred simultaneously, (+ 0.04 ± 0.07 s, p = 0.081), while occurred earlier by LPF (- 0.26 ± 0.1 s, p < 0.001). Removal of cardiac related impedance changes by ETA results in a ventilation signal more similar to the waveforms recorded by the ventilator, particularly regarding the slope of impedance changes and time at the minimum values as compared to LPF.
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J Clin Monit Comput · Jun 2020
Review Meta AnalysisAccuracy and precision of non-invasive cardiac output monitoring by electrical cardiometry: a systematic review and meta-analysis.
Cardiac output monitoring is used in critically ill and high-risk surgical patients. Intermittent pulmonary artery thermodilution and transpulmonary thermodilution, considered the gold standard, are invasive and linked to complications. Therefore, many non-invasive cardiac output devices have been developed and studied. ⋯ Despite the low bias for both adults and pediatrics, the MPE was not clinically acceptable. Electrical cardiometry cannot replace thermodilution and transthoracic echocardiography for the measurement of absolute cardiac output values. Future research should explore it's clinical use and indications.
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J Clin Monit Comput · Jun 2020
Clinical TrialAdjustment of oxygen reserve index (ORi™) to avoid excessive hyperoxia during general anesthesia.
The Oxygen Reserve Index (ORi™) is a non-invasive variable that reflects oxygenation continuously. The aims of this study were to examine the relationship between arterial partial pressure of oxygen (PaO2) and ORi during general anesthesia, and to investigate the usefulness of ORi as an indicator to avoid hyperoxia. Twenty adult patients who were scheduled for surgery under general anesthesia with arterial catheterization were enrolled. ⋯ The cut-off ORi value obtained from the receiver operating characteristic curve to detect PaO2 ≥ 150 mmHg was 0.21 (sensitivity 0.950, specificity 0.755). Four-quadrant plot analysis showed that the ORi trending of PaO2 was good (concordance rate was 100.0%). Hyperoxemia can be detected by observing ORi of patients under general anesthesia, and thus unnecessary administration of high concentration oxygen can possibly be avoided.
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J Clin Monit Comput · Jun 2020
Comparative StudyThe value of a superior vena cava collapsibility index measured with a miniaturized transoesophageal monoplane continuous echocardiography probe to predict fluid responsiveness compared to stroke volume variations in open major vascular surgery: a prospective cohort study.
Superior vena cava collapsibility index (SVC-CI) and stroke volume variation (SVV) have been shown to predict fluid responsiveness. SVC-CI has been validated only with conventional transoesophageal echocardiography (TEE) in the SVC long axis, on the basis of SVC diameter variations, but not in the SVC short axis or by SVC area variations. SVV was not previously tested in vascular surgery patients. ⋯ Our study validated the value of the SVC-CI measured as area variations in the SVC short axis to predict fluid responsiveness in anesthetized patients. An hTEE probe was used to monitor and measure the hSVC-CI but conventional TEE may also offer this new dynamic parameter. In our cohort of significant preoperative hypovolemic patients undergoing major open vascular surgery, hSVC-CI and SVV cutoff values of 37% and 15%, respectively, predicted fluid responsiveness with good accuracy.
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J Clin Monit Comput · Jun 2020
Duration of cardiac arrest requires different ventilation volumes during cardiopulmonary resuscitation in a pig model.
There are few studies examining the ventilation strategies recommended by current CPR guidelines. We investigated the influence of different minute volume applying to untreated cardiac arrest with different duration, on resuscitation effects in a pig model. 32 Landrace pigs with 4 or 8 min (16 pigs each) ventricular fibrillation (VF) randomly received two ventilation strategies during CPR. "Guideline" groups received mechanical ventilation with a tidal volume of 7 ml/kg and a frequency of 10/min, while "Baseline" groups received a tidal volume (10 ml/kg) and a frequency used at baseline to maintain an end-tidal PCO2 (PETCO2) between 35 and 40 mmHg before VF. Mean airway pressures and intrathoracic pressures (PIT) in the Baseline-4 min group were significantly higher than those in the Guideline-4 min group (all P < 0.05). ⋯ Higher ROSC was observed in the Baseline-8 min group than in the Guideline-8 min group (87.5% vs. 37.5%, P = 0.039). For 4 min VF but not 8 min VF, a guideline-recommended ventilation strategy had satisfactory results during CPR. A higher minute ventilation resulted in better outcomes for subjects with 8 min of untreated VF through thoracic pump.