Ultrasound assessment of diaphragm thickness, contractility, and strain in healthy pediatric patients

BACKGROUND

Ultrasound-based diaphragmatic assessments are becoming more common in pediatric acute care, but baseline pediatric diaphragm thickness and contractility values remain unknown.

METHODS

We conducted a prospective, observational study of healthy children aged <18 years undergoing elective surgery. Diaphragm thickness at end-expiration (Tdi-exp), thickening fraction (DTF) and excursion were measured by ultrasound during spontaneous breathing and during mechanical ventilation. Diaphragm strain and peak strain rate were ascertained post hoc. Measurements were compared across a priori specified age groups (<1 year, 1 to <3, 3 to <6, 6 to <12, and 12 to <18 years) and with versus without mechanical ventilation.

RESULTS

Fifty subjects were evaluated (n = 10 per age group). Baseline mean Tdi-exp was 0.19 ± 0.04 cm, DTF 0.19 ± 0.09, excursion 1.69 ± 0.97 cm, strain -10.3 ± 4.9, peak strain rate -0.48 ± 0.21 s-1 . No significant difference in Tdi-exp or DTF was observed across age groups (p > .05). Diaphragm excursion increased with age (p < .0001). Diaphragm strain was significantly greater in the 12-17-year age group (-14.3 ± 6.4), p = .048, but there were no age-related differences in peak strain rate (p = .08). During mechanical ventilation, there were significant decreases in DTF 0.12 ± 0.04 (p < .0001), excursion 1.08 ± 0.31 cm (p < .0001), strain -4.60 ± 1.93 (p < .0001), and peak strain rate -0.20 ± 0.10 s-1 (p < .0001) while there was no change in Tdi-exp 0.18 ± 0.03 cm (p = .25) when compared to baseline values.

CONCLUSION

Pediatric Tdi-exp, DTF, and diaphragm peak strain rate were similar across age groups. Diaphragm excursion and strain varied across age groups. All measures of diaphragm contractility were diminished during mechanical ventilation.

Fibrotic-Like Pulmonary Radiographic Patterns Are Not Associated With Adverse Outcomes in COVID-19 Chronic Critical Illness

OBJECTIVES

Pulmonary fibrosis is a feared complication of COVID-19. To characterize the risks and outcomes associated with fibrotic-like radiographic abnormalities in patients with COVID-19-related acute respiratory distress syndrome (ARDS) and chronic critical illness.

DESIGN

Single-center prospective cohort study.

SETTING

We examined chest CT scans performed between ICU discharge and 30 days after hospital discharge using established methods to quantify nonfibrotic and fibrotic-like patterns.

PATIENTS

Adults hospitalized with COVID-19-related ARDS and chronic critical illness (> 21 d of mechanical ventilation, tracheostomy, and survival to ICU discharge) between March 2020 and May 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We tested associations of fibrotic-like patterns with clinical characteristics and biomarkers, and with time to mechanical ventilator liberation and 6-month survival, controlling for demographics, comorbidities, and COVID-19 therapies. A total of 141 of 616 adults (23%) with COVID-19-related ARDS developed chronic critical illness, and 64 of 141 (46%) had a chest CT a median (interquartile range) 66 days (42-82 d) after intubation. Fifty-five percent had fibrotic-like patterns characterized by reticulations and/or traction bronchiectasis. In adjusted analyses, interleukin-6 level on the day of intubation was associated with fibrotic-like patterns (odds ratio, 4.40 per quartile change; 95% CI, 1.90-10.1 per quartile change). Other inflammatory biomarkers, Sequential Organ Failure Assessment score, age, tidal volume, driving pressure, and ventilator days were not. Fibrotic-like patterns were not associated with longer time to mechanical ventilator liberation or worse 6-month survival.

CONCLUSIONS

Approximately half of adults with COVID-19-associated chronic critical illness have fibrotic-like patterns that are associated with higher interleukin-6 levels at intubation. Fibrotic-like patterns are not associated with longer time to liberation from mechanical ventilation or worse 6-month survival.

Incidence, risk factors, progression, and involution in retinopathy of prematurity at a tertiary care center in South India

BACKGROUND

Retinopathy of prematurity (ROP) is a vasculoproliferative disorder of immature retina, seen in preterm babies. Multiple risk factors attribute to this condition. Our aim was to correlate the role of any early neonatal surgeries with low gestational age (GA) and birth weight (BW) on preterm babies as a risk factor on the progression of ROP.

METHODS

A prospective, cohort study conducted in a hospital in South India over 3 years, including 600 babies with GA <35 weeks and BW <2500 g. Babies were divided into Group A (ROP) and Group B (no ROP). Group A included A1 (severe ROP) and A2 (nonsevere ROP) based on early treatment of ROP classification. We compared various risk factors of ROP, specifically the association of any early neonatal surgery undergone by these babies, on progression of ROP. The Chi-square test, unpaired t-test, and one-way analysis of variance tests were used for the comparisons and considered statistically significant if P < 0.05.

RESULTS

28.7% babies developed ROP, with 37.6% requiring treatment (Aggressive ROP in 2.1% of babies). Low GA and BW, longer duration on ventilator, respiratory distress syndrome, apnea of prematurity, Patent Ductus Arteriosus, sepsis, anemia, thrombocytopenia, history of blood transfusion, and history of early neonatal surgery under GA were associated with babies with ROP (P < 0.005), strongly with severe ROP. The most common surgeries undergone by the babies developing ROP were inguinal herniotomy under general anesthesia.

CONCLUSION

The study predicts preterm babies undergoing early surgical interventions are at risk of progressing to severe ROP, hence warranting frequent follow-ups.

Imaging Regional Lung Structure and Function in Small Animals Using Synchrotron Radiation Phase-Contrast and K-Edge Subtraction Computed Tomography

Synchrotron radiation offers unique properties of coherence, utilized in phase-contrast imaging, and high flux as well as a wide energy spectrum which allow the selection of very narrow energy bands of radiation, used in K-edge subtraction imaging (KES) imaging. These properties extend X-ray computed tomography (CT) capabilities to quantitatively assess lung morphology, and to map regional lung ventilation, perfusion, inflammation, aerosol particle distribution and biomechanical properties, with microscopic spatial resolution. Four-dimensional imaging, allows the investigation of the dynamics of regional lung functional parameters simultaneously with structural deformation of the lung as a function of time. These techniques have proven to be very useful for revealing the regional differences in both lung structure and function which is crucial for better understanding of disease mechanisms as well as for evaluating treatment in small animal models of lung diseases. Here, synchrotron radiation imaging methods are described and examples of their application to the study of disease mechanisms in preclinical animal models are presented.

Association of Proximity to a Long-Term Acute Care Hospital With Hospital Tracheostomy Practices

OBJECTIVES

Availability of long-term acute care hospitals has been associated with hospital discharge practices. It is unclear if long-term acute care hospital availability can influence patient care decisions. We sought to determine the association of long-term acute care hospital availability at different hospitals with the likelihood of tracheostomy.

DESIGN

Retrospective cohort study.

SETTING

California Patient Discharge Database, 2016-2018.

PATIENTS

Adult patients receiving mechanical ventilation for respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Using the California Patient Discharge Database 2016-2018, we identified all mechanically ventilated patients and those who received tracheostomy. We determine the association between tracheostomy and the distance between each hospital and the nearest long-term acute care hospital and the number of long-term acute care hospital beds within 20 miles of each hospital. Among 281,502 hospitalizations where a patient received mechanical ventilation, 22,899 (8.1%) received a tracheostomy. Patients admitted to a hospital closer to a long-term acute care hospital compared with those furthest from a long-term acute care hospital had 38.9% (95% CI, 33.3-44.6%) higher odds of tracheostomy (closest hospitals 8.7% vs furthest hospitals 6.3%, adjusted odds ratio = 1.65; 95% CI, 1.40-1.95). Patients had a 32.4% (95% CI, 27.6-37.3%) higher risk of tracheostomy when admitted to a hospital with more long-term acute care hospital beds in the immediate vicinity (most long-term acute care hospital beds within 20 miles 8.9% vs fewest long-term acute care hospital beds 6.7%, adjusted odds ratio = 1.54; 95% CI, 1.31-1.80). Distance to the nearest long-term acute care hospital was inversely correlated with hospital risk-adjusted tracheostomy rates (ρ = -0.25; p < 0.0001). The number of long-term acute care hospital beds within 20 miles was positively correlated with hospital risk-adjusted tracheostomy rates (ρ = 0.22; p < 0.0001).

CONCLUSIONS

Proximity and availability of long-term acute care hospital beds were associated with patient odds of tracheostomy and hospital tracheostomy practices. These findings suggest a hospital effect on tracheostomy decision-making over and above patient case-mix. Future studies focusing on shared decision-making for tracheostomy are needed to ensure goal-concordant care for prolonged mechanical ventilation.

Factors associated with extubation failure in very low birth weight infants: a cohort study in the northeast Brazil

OBJECTIVES

Identifying and understanding the main risk factors associated with extubation failure of very low birthweight (VLBW) infants in different populations can subsequently help in establishing better criteria while taking decision of extubation. The aim of the study was to identify factors associated with extubation failure in VLBW infants.

METHODS

A cohort study of VLBW infants who underwent their first extubation between April 2018 and December 2019 in a Neonatal Intensive Care Unit, Alagoas, Brazil, were included in this study. Extubation failure was defined as reintubation within seven days of extubation. Relative risks of predictive variables different between the extubation success group (ES) and extubation failure group (EF) were estimated with a robust Poisson regression model.

RESULTS

Out of the 112 infants included, 26 (23%) cases exhibited extubation failure. Extremely low birth weight (RR 2.55, 95% CI 1.07, 6.06), mechanical ventilation duration for first extubation greater than seven days (RR 2.66, 95% CI 1.10, 6.45), vaginal delivery (RR 2.07, 95% CI 1.03, 4.18) and maternal chorioamnionitis (RR 4.89, 95% CI 1.26-18.98) remained independently associated with extubation failure. EF had a significant greater need for respiratory support, longer oxygen therapy duration, more bronchopulmonary dysplasia (BPD) and longer length of hospital stay, even when adjusted for confounding variables.

CONCLUSIONS

Extremely low birth weight infants needing mechanical ventilation, wherein the duration for first extubation was longer than seven days, with vaginal delivery and maternal chorioamnionitis failed more frequently at the first attempt of extubation. And this failure increased the risk of BPD and the length of hospital stay.

Development and validation of a novel informational booklet for pediatric long-term ventilation decision support

OBJECTIVES

To provide accessible, uniform, comprehensive, and balanced information to families deciding whether to initiate long-term ventilation (LTV) for their child, we sought to develop and validate a novel informational resource.

METHODS

The Ottawa Decision Support Framework was followed. Previous interviews with 44 lay and 15 professional stakeholders and published literature provided content for a booklet. Iterative versions were cognitive tested with six parents facing decisions and five pediatric intensivists. Ten parents facing decisions evaluated the booklet using the Preparation for Decision Making Scale and reported their decisional conflict, which was juxtaposed to the conflict of 21 parents who did not read it, using the Decisional Conflict Scale. Twelve home ventilation program directors evaluated the booklet's clinical sensibility and sensitivity, using a self-designed six-item questionnaire. Data presented using summary statistics.

RESULTS

The illustrated booklet (6th-grade reading level) has nine topical sections on chronic respiratory failure and invasive and noninvasive LTV, including the option to forgo LTV. Ten parents who read the booklet rated it as helping "Quite a bit" or more on all items of the Preparation for Decision Making Scale and had seemingly less decisional conflict than 21 parents who did not. Twelve directors rated it highly for clinical sensibility and sensitivity.

CONCLUSIONS

The LTV booklet was rigorously developed and favorably evaluated. It offers a resource to improve patient/family knowledge, supplement shared decision-making, and reduce decisional conflict around LTV decisions. Future studies should validate it in other settings and further study its effectiveness.

Protocolized ventilator weaning verses usual care: A randomized controlled trial

Background:

Protocolized ventilator weaning (PW) strategies utilizing spontaneous breathing trials (SBTs) result in shorter intubation duration and intensive care unit (ICU) length of stay (LOS). We compared respiratory therapy (RT)-driven PW versus usual care (UC) as it pertains to physiologic respiratory parameters, intubation duration, extubation success/reintubation rates, and ICU LOS.

Methods:

prospective, multicentric, randomized controlled trial was performed in closed medical and surgical ICUs with 24/7 in-house intensivist coverage at six academic medical centers in a resource-limited setting from October 18, 2007, to May 03, 2014. Extubation readiness was determined by the attending physician (UC) or the respiratory therapist (PW) using predefined criteria and SBT. Physiologic variables, serial blood gas measurements, and weaning indices were assessed including the Rapid Shallow Breathing Index (RSBI), negative inspiratory force (NIF), occlusion pressure (P0.1), and dynamic and static compliance (C_dyn and C_s).

Results:

total of 5502 patients were randomized (PW 2787; UC 2715), of which 167 patients died without ventilator weaning (PW 90; UC 77) and 645 patients were excluded (PW 365; UC 280). Finally, a total of 4200 patients were analyzed (PW 2075; UC 2125). The PW group displayed improvements in minute ventilation (P < 0.001), C_s and C_dyn(both P < 0.05), P0.1 (P < 0.001), NIF (P < 0.001), and RSBI (P < 0.001). Early re-intubation (≤48 h) rates were lower in the PW group (16.7% vs. 24.8%; P < 0.0001), as were late re-intubation rates (5.2% vs. 25.8%; P < 0.0001). Intubation duration was longer in the PW group (P < 0.001), however, hospital LOS was shorter (P < 0.001). Mortality was unchanged (P = 0.19).

Conclusion:

PW with RT-driven extubation decisions is safe, effective, and associated with decreased re-intubation (early and late), shorter hospital stays, increased intubation duration (statistically but not clinically significant), and unchanged in-patient mortality.

A sigmoidal fit for pressure-volume curves of idiopathic pulmonary fibrosis patients on mechanical ventilation: clinical implications

OBJECTIVE

Respiratory pressure-volume curves fitted to exponential equations have been used to assess disease severity and prognosis in spontaneously breathing patients with idiopathic pulmonary fibrosis. Sigmoidal equations have been used to fit pressure-volume curves for mechanically ventilated patients but not for idiopathic pulmonary fibrosis patients. We compared a sigmoidal model and an exponential model to fit pressure-volume curves from mechanically ventilated patients with idiopathic pulmonary fibrosis.

METHODS

Six idiopathic pulmonary fibrosis patients and five controls underwent inflation pressure-volume curves using the constant-flow technique during general anesthesia prior to open lung biopsy or thymectomy. We identified the lower and upper inflection points and fit the curves with an exponential equation, V = A-B.e-k.P, and a sigmoid equation, V = a+b/(1+e-(P-c)/d).

RESULTS

The mean lower inflection point for idiopathic pulmonary fibrosis patients was significantly higher (10.5 ± 5.7 cm H2O) than that of controls (3.6 ± 2.4 cm H₂O). The sigmoidal equation fit the pressure-volume curves of the fibrotic and control patients well, but the exponential equation fit the data well only when points below 50% of the inspiratory capacity were excluded.

CONCLUSION

The elevated lower inflection point and the sigmoidal shape of the pressure-volume curves suggest that respiratory system compliance is decreased close to end-expiratory lung volume in idiopathic pulmonary fibrosis patients under general anesthesia and mechanical ventilation. The sigmoidal fit was superior to the exponential fit for inflation pressure-volume curves of anesthetized patients with idiopathic pulmonary fibrosis and could be useful for guiding mechanical ventilation during general anesthesia in this condition.