High-flow nasal cannula (HFNC) is becoming the gold standard to treat respiratory distress at any age since it potentially provides several significant clinical advantages. An obstacle to the ...diffusion of this simple and effective system of oxygen therapy is the impossibility to know the optimal flow rate leading to such advantages that allows the reduction in the respiratory effort without causing hyperinflation. To assist clinicians during HFNC treatment in setting the optimal flow rate and in determining the most relevant parameters related to respiratory mechanics and the effort of the patient, we developed a new programmable data monitoring, acquisition, and elaborating system (Pro_HFNC). The application of Pro_HFNC is fully compatible with HFNC as it is interfaced with patient through a facial mask and two specific catheters. The unavoidable and unpredictable loss of air flow occurring around the contour of the mask is evaluated and compensated by a specific algorithm implemented by Pro_HFNC. Our preliminary clinical trials on pediatric patients treated with HFNC show that Pro_HFNC is actually capable to detect for any specific patient both the lower threshold of the delivered flow beyond which the benefits of HFNC application are reached and all the parameters useful for a complete evaluation of the respiratory profile. Pro_HFNC can really help physicians in setting the optimal flow rate during HFNC treatment, thus allowing for the most effective HFNC performance.
The first results obtained by the DAMA/LIBRA–phase2 experiment are presented. The data have been collected over six independent annual cycles corresponding to a total exposure of 1.13 ton × year, ...deep underground at the Gran Sasso National Laboratory. The DAMA/LIBRA–phase2 apparatus, about 250 kg highly radio-pure NaI(Tl), profits from a second generation high quantum efficiency photomultipliers and of new electronics with respect to DAMA/LIBRA–phase1. The improved experimental configuration has also allowed to lower the software energy threshold. The DAMA/LIBRA–phase2 data confirm the evidence of a signal that meets all the requirements of the model independent Dark Matter annual modulation signature, at 9.5 σ C.L. in the energy region (1–6) keV. In the energy region between 2 and 6 keV, where data are also available from DAMA/NaI and DAMA/LIBRA–phase1, the achieved C.L. for the full exposure (2.46 ton × year) is 12.9 σ .
Introduction
Although neonatal breathing patterns vary after perinatal asphyxia, whether they change during therapeutic hypothermia (TH) remains unclear. We characterized breathing patterns in ...infants during TH for hypoxic-ischemic encephalopathy (HIE) and normothermia after rewarming.
Methods
In seventeen spontaneously breathing infants receiving TH for HIE and in three who did not receive TH, we analyzed respiratory flow and esophageal pressure tracings for respiratory timing variables, pulmonary mechanics and respiratory effort. Breaths were classified as braked (inspiratory:expiratory ratio ≥1.5) and unbraked (<1.5).
Results
According to the expiratory flow shape braked breaths were chategorized into early peak expiratory flow, late peak expiratory flow, slow flow, and post-inspiratory hold flow (PiHF). The most braked breaths had lower rates, larger tidal volume but lower minute ventilation, inspiratory airway resistance and respiratory effort, except for the PiHF, which had higher resistance and respiratory effort. The braked pattern predominated during TH, but not during normothermia or in the uncooled infants.
Conclusions
We speculate that during TH for HIE low respiratory rates favor neonatal braked breathing to preserve lung volume. Given the generally low respiratory effort, it seems reasonable to leave spontaneous breathing unassisted. However, if the PiHF pattern predominates, ventilatory support may be required.
Abnormal breathing can be a symptom of an unhealthy status. Conventional diagnostic exams involve cumbersome and intrusive instrumentation, such as nasal cannulas, that is, uncomfortable for the user ...and that, most of the times, do not consider the breathing asymmetries between the two nostrils. This article describes a two-channel flexible epidermal sensor for the wireless and less-invasive bilateral monitoring of nasal breathing based on temperature measurement. The device is suitable to adhere to the prolabium and comprises two coupled T-match antennas whose Ultra-High Frequency (UHF) Radio-Frequency Identification (RFID) Integrated Circuits (ICs) are placed at the entrance of the nostrils. They are provided with embedded temperature sensors so that they implement both sensing and transmission of the data. A measurement campaign is carried out to provide a quantitative characterization of the dual-channel device as a breath sensor by comparison with a conventional flow meter. The two nostrils can be independently monitored due to a negligible cross-sensitivity of the two ICs' temperature data. Moreover, temperature-based measurements proved capable to reproduce typical clinical breathing features, with less than 12% uncertainty with respect to flow waveforms.
•Work of breathing (WOB) is hard to measure during high-flow nasal cannula (HFNC).•A monitoring facemask and pneumotachograph simplifies the task apart from leakages.•A leak-correction algorithm ...allows WOB measurement via pneumotachography during HFNC.•Tested on a mechanical lung model and in vivo our system reliably computed WOB.
Measuring work of breathing (WOB) is an intricate task during high-flow nasal cannula (HFNC) therapy because the continuous unidirectional flow toward the patient makes pneumotachography technically difficult to use. We implemented a new method for measuring WOB based on a differential pneumotachography (DP) system, equipped with one pneumotachograph inserted in the HFNC circuit and another connected to a monitoring facemask, combined with a leak correction algorithm (LCA) that corrects flow measurement errors arising from leakage around the monitoring facemask. To test this system, we used a mechanical lung model that provided data to compare LCA-corrected respiratory flow, volume and time values with effective values obtained with a third pneumotachograph used instead of the LCA to measure mask flow leaks directly. Effective and corrected volume and time data showed high agreement (Bland–Altman plots) even at the highest leak. Studies on two healthy adult volunteers confirmed that corrected respiratory flow combined with esophageal pressure measurements can accurately determine WOB (relative error < 1%). We conclude that during HFNC therapy, a DP system combined with a facemask and an algorithm that corrects errors due to flow leakages allows pneumotachography to measure reliably the respiratory flow and volume data needed for calculating WOB.
Objectives
To determine whether in infants with bronchiolitis admitted to a pediatric intensive care unit (PICU) the starting rate for high‐flow nasal cannula (HFNC) therapy set by the attending ...physicians upon clinical judgment meets patients' peak inspiratory flow (PIF) demands and how it influences respiratory mechanics and breathing effort.
Methodology
We simultaneously obtained respiratory flow and esophageal pressure data from 31 young infants with moderate‐to‐severe bronchiolitis before and after setting the HFNC rate at 1 L/kg/min (HFNC‐1), 2 L/kg/min (HFNC‐2) or upon clinical judgment and compared data for PIF, respiratory mechanics, and breathing effort.
Results
Before HFNC oxygen therapy started, 16 (65%) infants had a PIF less than 1 L/kg/min (normal‐PIF) and 15 (45%) had a PIF more than or equal to 1 L/kg/min (high‐PIF). Normal‐PIF‐infants had higher airway resistance (p < .001) and breathing effort indexes (e.g., pressure rate product per min PTP/min, p = .028) than high‐PIF‐infants. Starting the HFNC rate upon clinical judgment (1.20–2.05 L/kg/min) met all infants' PIFs. In normal‐PIF‐infants, the clinically judged flow rate increased PIF (p = .081) and tidal volume (p = .029), reduced airway resistance (p = .011), and intrinsic positive end‐expiratory pressure (p = .041), whereas, in both high‐PIF and normal‐PIF infants, it decreased respiratory rate (p < .001) and indexes of breathing effort such as PTP/min (in normal‐PIF infants, p = .004; in high‐PIF infants, p = .001). The 2 L/kg/min but not 1 L/kg/min rate induced similar effects.
Conclusions
The wide PIF distribution in our PICU population of infants with bronchiolitis suggests two disease phenotypes whose therapeutic options might differ. An initial flow rate of nearly 2 L/kg/min meets patients' flow demands and improves respiratory mechanics and breathing effort.
Apnoea, desaturations and bradycardias are common problems in preterm infants which can be treated with nasal continuous positive airway pressure (NCPAP) and nasal intermittent positive pressure ...ventilation (NIPPV). It is unclear whether synchronised NIPPV (SNIPPV) would be even more effective.
To assess the effects of flow-SNIPPV, NIPPV and NCPAP on the rate of desaturations and bradycardias in preterm infants and, secondarily, to evaluate their influence on pattern of breathing and gas exchange.
Nineteen infants (mean gestational age at study 30 weeks, 9 boys) with apnoeic spells were enrolled in a randomised controlled trial with a cross-over design. They received flow-SNIPPV, NIPPV and NCPAP for 4 h each. All modes were provided by a nasal conventional ventilator able to provide synchronisation by a pneumotachograph. The primary outcome was the event rate of desaturations (≤80% arterial oxygen saturation) and bradycardias (≤80 bpm) per hour, obtained from cardiorespiratory recordings. The incidence of central apnoeas (≥10 s) as well as baseline heart rate, FiO2, SpO2, transcutaneous blood gases and respiratory rate were also evaluated.
The median event rate per hour during flow-SNIPPV, NIPPV and NCPAP was 2.9, 6.1 and 5.9, respectively (p<0.001 and 0.009, compared with flow-SNIPPV). Central apnoeas per hour were 2.4, 6.3 and 5.4, respectively (p=0.001, for both compared with flow-SNIPPV), while no differences in any other parameter studied were recorded.
Flow-SNIPPV seems more effective than NIPPV and NCPAP in reducing the incidence of desaturations, bradycardias and central apnoea episodes in preterm infants.
The results obtained with the total exposure of 1.04 ton × yr collected by DAMA/LIBRA-phase1 deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. during 7 annual cycles are ...summarized. The DAMA/LIBRA-phase1 and the former DAMA/NaI data (cumulative exposure 1.33 ton × yr, corresponding to 14 annual cycles) give evidence at 9.3 σ C.L. for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radiopure NaI(Tl) target. The modulation amplitude of the single-hit events in the (2–6) keV energy interval is 0.0112 ± 0.0012 cpd/kg/keV; the measured phase is 144 ± 7 days and the measured period is 0.998 ± 0.002 yr; values are in a good well in agreement with those expected for DM particles. No systematic or side reactions able to mimic the exploited DM signature have been found or suggested by anyone over more than a decade. Some of the perspectives of the presently running DAMA/LIBRA-phase2 are outlined.
Background
Nasopharyngeal tubes are useful in pediatric anesthesia for insufflating oxygen and anesthetics. During nasopharyngeal tube‐anesthesia, gas insufflation provides some positive ...oropharyngeal pressure that differs from the proximal airway pressure owing to the flow‐dependent pressure drop across the nasopharyngeal tube (ΔPNPT).
Aims
This study aimed to investigate whether ΔPNPT could be used for calculating oropharyngeal pressure during nasopharyngeal tube‐assisted anesthesia.
Methods
In a physical model of nasopharyngeal tube‐anesthesia, using Rohrer's equation, we calculated ΔPNPT for three nasopharyngeal tubes (3.5, 4.0, and 5.0 mm inner diameter) under oxygen and several sevoflurane in oxygen combinations in two ventilatory scenarios (continuous positive airway pressure and intermittent positive pressure ventilation). We then calculated oropharyngeal pressure as proximal airway pressure minus ΔPNPT. Calculated and measured oropharyngeal pressure couples of values were compared with the root mean square deviation to assess accuracy. We also investigated whether oropharyngeal pressure accuracy depends on the nasopharyngeal tube diameter, flow rate, gas composition, and leak size. Using ΔPNPT charts, we tested whether ΔPNPT calculation was feasible in clinical practice.
Results
When we tested small‐diameter nasopharyngeal tubes at high‐flow or high‐peak inspiratory pressure, proximal airway pressure measurements markedly overestimated oropharyngeal pressure. Comparing measured and calculated maximum and minimum oropharyngeal pressure couples yielded root mean square deviations less than 0.5 cmH2O regardless of ventilatory modality, nasopharyngeal tube diameter, flow rate, gas composition, and leak size.
Conclusion
During nasopharyngeal tube‐assisted anesthesia, proximal airway pressure readings on the anesthetic monitoring machine overestimate oropharyngeal pressure especially for smaller‐diameter nasopharyngeal tubes and higher flow, and to a lesser extent for large leaks. Given the importance of calculating oropharyngeal pressure in guiding nasopharyngeal tube ventilation in clinical practice, we propose an accurate calculation using Rohrer's equation method, or approximating oropharyngeal pressure from flow and pressure readings on the anesthetic machine using the ΔPNPT charts.
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