scholarly journals First Attempt at Using Electrical Impedance Tomography to Predict High Flow Nasal Cannula Therapy Outcomes at an Early Phase

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhe Li ◽  
Zhiyun Zhang ◽  
Qian Xia ◽  
Danling Xu ◽  
Shaojie Qin ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Final Analysis ◽  
High Flow ◽  
Nasal Cannula ◽  
Time To Failure ◽  
High Flow Nasal Cannula ◽  
Impedance Tomography ◽  
Rapid Shallow Breathing Index ◽  
Significant Difference

Objective: Spatial and temporal ventilation distributions in patients with acute respiratory failure during high flow nasal cannula (HFNC) therapy were previously studied with electrical impedance tomography (EIT). The aim of the study was to explore the possibility of predicting HFNC failure based on various EIT-derived parameters.Methods: High flow nasal cannula failure was defined reintubation within 48 h after HFNC. EIT was performed with the patients spontaneously breathing in the supine position at the start of HFNC. EIT-based indices (comprising the global inhomogeneity index, center of ventilation, ventilation delay, rapid shallow breathing index, minute volume, and inspiration to expiration time) were explored and evaluated at three time points (prior to HFNC, T1; 30 min after HFNC started, T2; and 1 h after, T3).Results: A total of 46 subjects were included in the final analysis. Eleven subjects had failed HFNC. The time to failure was 27.8 ± 12.4 h. The ROX index (defined as SpO2/FiO2/respiratory rate) for HFNC success patients was 8.3 ± 2.7 and for HFNC failure patients, 6.2 ± 1.8 (p = 0.23). None of the investigated EIT-based parameters showed significant differences between subjects with HFNC failure and success. Further subgroup analysis indicated that a significant difference in ventilation inhomogeneity was found between ARDS and non-ARDS [0.54 (0.37) vs. 0.46 (0.28) as evaluated with GI, p < 0.01]. Ventilation homogeneity significantly improved in ARDS after 60-min HFNC treatment [0.59 (0.20) vs 0.57 (0.19), T1 vs. T3, p < 0.05].Conclusion: Spatial and temporal ventilation distributions were slightly but insignificantly different between the HFNC success and failure groups. HFNC failure could not be predicted by changes in EIT temporal and spatial indexes of ventilation distribution within the first hour. Further studies are required to predict the outcomes of HFNC.

Respiratory Drive in Patients with Sepsis and Septic Shock: Modulation by High-flow Nasal Cannula

2021 ◽  
Author(s):  
Tommaso Mauri ◽  
Elena Spinelli ◽  
Bertrand Pavlovsky ◽  
Domenico Luca Grieco ◽  
Irene Ottaviani ◽  
...  
Keyword(s):  
Septic Shock ◽  
Esophageal Pressure ◽  
Lung Compliance ◽  
High Flow ◽  
Nasal Cannula ◽  
Low Flow ◽  
Respiratory Drive ◽  
High Flow Nasal Cannula ◽  
Impedance Tomography ◽  
Sepsis And Septic Shock

Background Experimental and pilot clinical data suggest that spontaneously breathing patients with sepsis and septic shock may present increased respiratory drive and effort, even in the absence of pulmonary infection. The study hypothesis was that respiratory drive and effort may be increased in septic patients and correlated with extrapulmonary determinant and that high-flow nasal cannula may modulate drive and effort. Methods Twenty-five nonintubated patients with extrapulmonary sepsis or septic shock were enrolled. Each patient underwent three consecutive steps: low-flow oxygen at baseline, high-flow nasal cannula, and then low-flow oxygen again. Arterial blood gases, esophageal pressure, and electrical impedance tomography data were recorded toward the end of each step. Respiratory effort was measured as the negative swing of esophageal pressure (ΔPes); drive was quantified as the change in esophageal pressure during the first 500 ms from start of inspiration (P0.5). Dynamic lung compliance was calculated as the tidal volume measured by electrical impedance tomography, divided by ΔPes. The results are presented as medians [25th to 75th percentile]. Results Thirteen patients (52%) were in septic shock. The Sequential Organ Failure Assessment score was 5 [4 to 9]. During low-flow oxygen at baseline, respiratory drive and effort were elevated and significantly correlated with arterial lactate (r = 0.46, P = 0.034) and inversely with dynamic lung compliance (r = –0.735, P < 0.001). Noninvasive support by high-flow nasal cannula induced a significant decrease of respiratory drive (P0.5: 6.0 [4.4 to 9.0] vs. 4.3 [3.5 to 6.6] vs. 6.6 [4.9 to 10.7] cm H2O, P < 0.001) and effort (ΔPes: 8.0 [6.0 to 11.5] vs. 5.5 [4.5 to 8.0] vs. 7.5 [6.0 to 12.6] cm H2O, P < 0.001). Oxygenation and arterial carbon dioxide levels remained stable during all study phases. Conclusions Patients with sepsis and septic shock of extrapulmonary origin present elevated respiratory drive and effort, which can be effectively reduced by high-flow nasal cannula. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Short-Term High-Flow Nasal Cannula for Moderate to Severe Bronchiolitis Is Effective in a General Pediatric Ward

2019 ◽  
Vol 58 (14) ◽  
pp. 1522-1527 ◽  
Author(s):  
Nimrod Sachs ◽  
Eran Rom ◽  
Tommy Schonfeld ◽  
Rachel Gavish ◽  
Itay Berger ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Severity Score ◽  
Final Analysis ◽  
High Flow ◽  
Nasal Cannula ◽  
High Flow Nasal Cannula ◽  
Short Term ◽  
Pediatric Ward ◽  
Physiological Benefits

We examined the clinical and physiological benefits of heated humidified high-flow nasal cannula (HHHFNC) in treating pediatric bronchiolitis in a general pediatric ward. Children aged 0 to 2 years, hospitalized with moderate to severe bronchiolitis, were connected to HHHFNC. Each child was evaluated at 4- to 10-hour intervals, both on and off the device, using the Wang et al Bronchiolitis Severity score and transcutaneous CO2 monitor. Sixteen children were included in the final analysis. The Bronchiolitis Severity score improved by 3 points during the first and second intervals ( P = .001). Transcutaneous CO2 values were reduced by an average 8.7 mm Hg ( P = .001). No adverse effects were noted in children connected to the device. The HHHFNC device used in a general pediatric ward setting served as a safe and efficacious tool in treating moderate to severe bronchiolitis. Immediate clinical and physiological improvement was observed and maintained 1 to 4 hours after disconnection from the device.

scholarly journals High-Flow Nasal Cannula: A Promising Oxygen Therapy for Patients with Severe Bronchial Asthma Complicated with Respiratory Failure

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Wanru Geng ◽  
Wuliji Batu ◽  
Shuhong You ◽  
Zhaohui Tong ◽  
Hangyong He
Keyword(s):  
Respiratory Failure ◽  
Bronchial Asthma ◽  
Oxygen Therapy ◽  
Response Rate ◽  
High Flow ◽  
Nasal Cannula ◽  
High Flow Nasal Cannula ◽  
Therapy Technique ◽  
Significant Difference ◽  
Life Threatening

Severe bronchial asthma complicated with respiratory failure, a common critical illness in respiratory medicine, may be life-threatening. High-flow nasal cannula (HFNC) is a novel oxygen therapy technique developed in recent years. HFNC was applied in this study for treating adult patients with severe bronchial asthma complicated with respiratory failure. Its efficacy was analyzed comparatively to conventional oxygen therapy (COT). HFNC and COT were randomly performed based on conventional treatment. The HFNC group was similar to COT-treated patients in terms of response rate, with no significant difference in efficacy between the two groups. In patients with bronchial asthma, effectively increased PO2 and reduced PCO2 were observed after treatment in both groups. However, HFNC was more efficient than COT in elevating PO2 in patients with severe bronchial asthma complicated with respiratory failure, while no statistically significant difference in PCO2 reduction was found between the two groups. Heart rate (HR) and respiratory rate (RR) between the two groups on admission (0 h) and at 2, 8, 24, and 48 h after admission were compared. Both indicators significantly decreased with time. No significant differences in HR and RR were found between the groups at 0, 2, and 8 h after admission. However, these indicators were significantly lower in the HFNC group compared with the COT group at 24 and 48 h after admission. HFNC could significantly elevate PO2 and reduce HR and RR. Thus, it is a promising option for patients with severe bronchial asthma complicated with respiratory failure.

scholarly journals Efficacy of High-flow Nasal Cannula Oxygen Therapy in Patients with Mild Hypercapnia

2021 ◽  
Author(s):  
Lingling Su ◽  
Qinyu Zhao ◽  
Taotao Liu ◽  
Yujun Xu ◽  
Weichun Li ◽  
...  
Keyword(s):  
Oxygen Therapy ◽  
Medical Information ◽  
Characteristic Curve ◽  
Predictive Performance ◽  
High Flow ◽  
Nasal Cannula ◽  
Intubation Rate ◽  
High Flow Nasal Cannula ◽  
Inpatient Hospitalization ◽  
Significant Difference

Abstract Objectives: To investigate the indications of high-flow nasal cannula (HFNC) oxygen therapy among patients with mild hypercapnia and to explore the predictors of intubation when HFNC fails.Methods: This retrospective study was conducted based on the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Adult patients with mild hypercapnia (45<PaCO2≤60 mmHg) received either HFNC or noninvasive ventilation (NIV) oxygen therapy. Propensity score matching (PSM) was implemented to increase between-group comparability. The Kaplan-Meier method was used to estimate overall survival and cumulative intubation rates, while 28-day mortality, 48-hour and 28-day intubation rates were compared using the Chi-square test. The predictive performances of HR/SpO2 and the ROX index (the ratio of SpO2/FiO2 to respiratory rate) at 4 hours were assessed regarding HFNC failure, which was determined if intubation was given within 48 hours after the initiation of oxygen therapy. The area under the receiver operating characteristic curve (AUC) for HR/SpO2 and the ROX index were calculated and compared.Results: A total of 524,520 inpatient hospitalization records were screened, 106 patients in HFNC group and 106 patients in NIV group were successfully matched. No significant difference in 48-hour intubation rate between the HFNC group and the NIV group (14.2% vs. 8.5%, P=0.278); patients receiving HFNC had higher 28-day intubation rate (26.4% vs. 14.2%, P=0.029), higher 28-day mortality (17.9% vs. 8.5%, P=0.043), longer ICU length of stay (4.4 vs. 3.3 days, P=0.019), compared to those of NIV group. The AUC of HR/SpO2 at 4 hours after the initiation of HFNC yielded around 0.660 for predicting 48-hour intubation, greater than that of the ROX index with an AUC of 0.589 (P<0.01).Conclusions: HFNC therapy cannot completely replace NIV for patients with mild hypercapnia. As opposed to the ROX index, a modest, yet improved predictive performance is demonstrated using HR/SpO2 in predicting the failure of HFNC among these patients.

scholarly journals Imaging fascicular organization of peripheral nerves with fast neural Electrical Impedance Tomography (EIT)

2020 ◽  
Author(s):  
Enrico Ravagli ◽  
Svetlana Mastitskaya ◽  
Nicole Thompson ◽  
Francesco Iacoviello ◽  
Paul R Shearing ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Peripheral Nerves ◽  
Electrical Impedance ◽  
Electrode Array ◽  
Compound Action Potential ◽  
Micro Computed Tomography ◽  
Impedance Tomography ◽  
Tissue Impedance ◽  
Significant Difference ◽  
Stimulation Of

Imaging of the compound action potential (CAP) in fascicles in peripheral nerves could help avoid side effects in neuromodulation by selective stimulation of identified fascicles. Existing methods have low resolution, limited imaging depth, or are invasive. We propose fast neural electrical impedance tomography (EIT), which allows fascicular CAP imaging with a high resolution of ∼200 μm, <1 ms. This uses a non-penetrating flexible cuff electrode array with 14 circumferential electrodes. This has been validated in rat sciatic nerve by comparison to micro-computed tomography (microCT) and histology with fluorescent dextran tracers (n=5). With EIT, there were reproducible localized changes in tissue impedance in response to stimulation of individual fascicles (tibial, peroneal and sural). The reconstructed EIT images corresponded to microCT scans and neural tracer histology, with significant separation between the fascicles (p<0.01), and no significant difference between techniques. The standard deviation from the mean fascicle position for EIT was 86 μm (6% of nerve diameter). This suggests fast neural EIT can reliably image the functional fascicular anatomy of the nerves and so aid selective neuromodulation.

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