Respiratory care最新文献

Background: In acute hypoxemic respiratory failure (AHRF), spontaneous breathing effort can generate excessive regional lung stress and strain manifesting as pendelluft. Higher PEEP may reduce pendelluft and reduce regional lung stress and strain during spontaneous breathing. This study aimed to establish whether higher or lower PEEP ameliorates pendelluft and to characterize factors determining the presence and magnitude of pendelluft during spontaneous breathing efforts. Methods: This study was a randomized crossover trial of higher versus lower PEEP applied after systematically initiating spontaneous breathing in subjects with moderate or severe AHRF. The presence and volume of pendelluft were assessed by electrical impedance tomography (EIT). Results: EIT recordings were available for 20 of 30 subjects enrolled in the trial. After initiating spontaneous breathing, 11/20 exhibited pendelluft (proportion 55% [95% CI 32-76]). Following PEEP titration, the prevalence of pendelluft was not different between higher versus lower PEEP levels (50% vs 50%, P = .55). When present, pendelluft volume was generally small (median 28 [interquartile range 8-93] mL) but ranged as high as 364 mL. Pendelluft was associated with higher respiratory effort (esophageal pressure [P_es] swing [ΔP_es] median -15 cm H₂O vs ΔP_es median -8 cm H₂O, P = .01), higher pulmonary flow resistance (median 8 cm H₂O/L/s vs median 3 cm H₂O/L/s, P < .001), and higher dynamic pulmonary elastance (median 5.0 cm H₂O/mL/kg predicted body weight vs median 3.2 cm H₂O/mL/kg predicted body weight, P = .03). Conclusions: Pendelluft reflecting increased regional lung stress and strain is likely common during spontaneous breathing effort in patients with AHRF but was not systematically affected by applying higher PEEP. The presence and magnitude of pendelluft depended on respiratory effort and lung mechanics.

Background: Intraoperative bronchospasm in pediatric patients supported through laryngeal mask airways (LMAs) is commonly treated with pressurized metered-dose inhaler (pMDI) albuterol. The aim of the study was to evaluate delivery of pMDI albuterol through LMAs under different conditions in a model of infant/child supported with a ventilator. Methods: We compared drug delivery efficiency of 4 actuations of albuterol pMDI (captured on a filter placed between the LMA and a test lung), drug deposition in the circuit (elbow) and in the LMA under different experimental conditions. Outcomes were expressed of percentage of nominal dose. We compared devices (valved holding chamber [VHC] and adapter), timing of administration (inspiration and expiration), tidal volumes (50 mL and 100 mL), mode of actuation (single and multiple), and LMA sizes (1, 1.5, and 2). Multiple regression analysis was used to evaluate the contribution of each to these components to the outcomes. P < .05 was considered statistically significant. Results: Results are expressed as median (interquartile range) of pooled data. Drug delivery efficiency was 0% (0-1.1) and 6.3% (3.2-14.7) for adapter and VHC, respectively. Elbow deposition was 25.8% (19.2-63.3) and 2.9% (1.4-6.4) for adapter and VHC, respectively. LMA deposition was 2.6% (1.3-4.6) and 4.6% (2.9-6.1) for adapter and VHC, respectively. Multiple regression analysis showed that device, timing of actuation, and LMA size explained 33%, 17%, and 8% of the observed variation in delivery efficiency (R² 0.63), respectively. Multiple regression analysis showed that device and timing of actuation explained 52% and 16% of the observed variation, respectively (R² 0.70). Multiple regression analysis poorly explained factors associated with LMA deposition (R² 0.22). Conclusions: Using a VHC, actuating the pMDI during exhalation, and using a small LMA size increased drug delivery efficiency. The adapter was an inefficient add-on device for aerosol delivery with a pMDI through an LMA that caused significant circuit deposition.

Background: CPAP benefits preterm infants with respiratory distress, including reduced bronchopulmonary dysplasia (BPD) incidence, surfactant use, and extubation failure. Successful CPAP weaning also promotes oral feeding. However, there is no consensus on the optimal weaning of CPAP in neonates. This study aimed to determine the effects of CPAP weaning guideline implementation on neonatal outcomes. Methods: CPAP gradual pressure weaning guidelines were implemented in the Penn State Children's Hospital neonatal ICU in 2020. We included baseline data from infants (epoch 1) before guideline implementation in 2018-2019. We included infants (epoch 2) after implementing the guidelines during 2020-2021. The inclusion criteria were infants < 32 weeks gestation with CPAP support. Adherence with the CPAP weaning guidelines was the primary process measure. Primary outcome measures included successful CPAP wean on the first attempt. Balancing measures used were total days on respiratory support and hospital length of stay. Results: One hundred ninety-five infants were included in this study, 95 infants in epoch 1 before guideline implementation and 100 infants in epoch 2 after implementing guidelines. Infants in the 2 epochs were similar in median gestational age at 29 weeks versus 30 weeks (P = .47) and were similar in median birthweight at 1,190 g versus 1,130 g (P = .73). After implementing weaning guidelines, the successful weaning off CPAP improved from 9.5% to 54% (P < .001). The total days needed to achieve full oral feeds decreased by 7 d (29 median d vs 22 median d, P < .001). The BPD incidence was not significantly different between the 2 epochs at 17% versus 16%, P = .87. There was no difference in total days of respiratory support, total length of stay, the number of infants discharged on home nasogastric feeding, and demographic variables. Conclusions: The implementation of the bubble CPAP weaning guideline improved the successful weaning of CPAP and promoted oral feeding in preterm infants.

Background: Respiratory failure in infants is a common reason for admission to the pediatric ICU (PICU). Although high-flow nasal cannula (HFNC) is the preferred first-line treatment at our institution, some infants require CPAP or noninvasive ventilation (NIV). Here we report our experience using CPAP/NIV in infants <10 kg. Methods: We conducted a retrospective review of infants <10 kg treated with CPAP/NIV in our PICUs between July 2017-May 2021 in the initial phase of treatment. Demographic, support type and settings, vital signs, pulse oximetry, and intubation data were extracted from the electronic health record. We compared subjects successfully treated with CPAP/NIV with those who required intubation. Results: We studied 62 subjects with median (interquartile range) age 96 [6.5-308] d and weight 4.5 (3.4-6.6) kg. Of these, 22 (35%) required intubation. There were no significant differences in demographics, medical history, primary interface, pre-CPAP/NIV support, and device used to deliver CPAP/NIV. HFNC was used in 57 (92%) subjects before escalation to CPAP/NIV. Subjects who failed CPAP/NIV were less likely to have bronchiolitis (27% vs 60%, P = .040), less likely to be discharged from the hospital to home (68% vs 93%, P = .02), had a longer median hospital length of stay (LOS) (26.9 [21-50.5] d vs 10.4 [5.6-28.4] d, P = .002), and longer median ICU LOS (14.6 [7.9-25.2] d vs 5.8 [3.8-12.4] d, P = .004). Initial vital signs and F_IO2 were similar, but S_pO2 was lower and F_IO2 higher at 6 h and 12 h after support initiation for subjects who failed CPAP/NIV. Initial CPAP/NIV settings were similar, but subjects who failed CPAP/NIV had higher maximum and final inspiratory/expiratory pressure. Conclusions: Most infants who failed initial HFNC support were successfully managed without intubation using NIV or CPAP. Bronchiolitis was associated with a lower rate of CPAP/NIV failure, whereas lower S_pO2 and higher F_IO2 levels were associated with higher rates of intubation.

Background: In pediatric patients, the intracuff pressure of endotracheal tubes should be as low as possible to prevent injury to the tracheal mucosal wall. The conventional stethoscope-guided technique relies solely on the operator's sensitivity of audible detection, which may lead to increased intracuff pressure. This study was conducted to compare the flow-volume loop guided technique for endotracheal tube cuff inflation with the stethoscope-guided technique and to determine whether the flow-volume loop guided technique results in lower and more consistent intracuff pressure. Methods: The participants were randomized to undergo either the flow-volume loop guided or the stethoscope-guided cuff inflation technique. In the flow-volume loop guided group, the cuff was inflated until the flow-volume loop was completely sealed. In the stethoscope-guided group, the cuff was inflated until the leakage was not audible. Cuff inflation was performed twice with incremental volumes of 0.5 mL and 0.2 mL to determine the consistency of the methods. The primary outcome was the intracuff pressure, and the secondary outcome was the incidence of postextubation complications. Results: Eighty participants (4 to 12 years old) were included in this study. The use of the flow-volume loop guided technique was associated with a lower cuff pressure versus use of the stethoscope-guided technique when inflated at the 0.5-mL increment [14 (6-18) cm H₂O vs 19 (9-24) cm H₂O; P < .001] and at the 0.2-mL increment [14 (6-18) cm H₂O vs 18 (9-24) cm H₂O; P < .001], with better consistency between the measured cuff pressures (z = -2.299; P = .02). The presence of postextubation complications (6/80) was not significantly different between the 2 groups but was associated with the American Society of Anesthesiologists physical status (P < .001). Conclusions: The flow-volume loop guided technique for endotracheal tube cuff inflation is a more objective technique that effectively seals the airway with the lower cuff pressure to allow for mechanical ventilation in pediatric subjects during anesthesia.