Pediatric upper airway obstruction: interobserver variability is the road to perdition

Air leak test in the Paediatric Intensive Care Unit (ALTIPICU): rationale and protocol for a prospective multicentre observational study

INTRODUCTION

In children, respiratory distress due to upper airway obstruction (UAO) is a common complication of extubation. The quantitative cuff-leak test (qtCLT) is a simple, rapid and non-invasive test that has not been extensively studied in children. The objective of the ongoing study whose protocol is reported here is to investigate how well the qtCLT predicts UAO-related postextubation respiratory distress in paediatric intensive care unit (PICU) patients.

METHODS AND ANALYSIS

Air Leak Test in the Paediatric Intensive Care Unit is a multicentre, prospective, observational study that will recruit 900 patients who are aged 2 days post-term to 17 years and ventilated through a cuffed endotracheal tube for at least 24 hours in any of 19 French PICUs. Within an hour of planned extubation, the qtCLT will be performed as a sequence of six measurements of the tidal volume with the cuff inflated then deflated. The primary outcome is the occurrence within 48 hours after extubation of severe UAO defined as combining a requirement for intravenous corticosteroid therapy and/or ventilator support by high-flow nasal cannula and/or by non-invasive ventilation or repeat invasive mechanical ventilation with a Westley score ≥4 with at least one point for stridor at each initiation. The results of the study are expected to identify risk factors for UAO-related postextubation respiratory distress and extubation failure, thereby identifying patient subgroups most likely to require preventive interventions. It will also determine whether qtCLT appears to be a reliable method to predict an increased risk for postextubation adverse events as severe UAO.

ETHICS AND DISSEMINATION

The study was approved by the Robert Debré University Hospital institutional review board (IRB) on September 2021 (approval #2021578). The report of Robert Debré University Hospital IRB is valid for all sites, given the nature of the study with respect to the French law. The results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT05328206.

Factors Associated With Post-Extubation Stridor in Infants Intubated in the Pediatric ICU

BACKGROUND

Post-extubation stridor (PES) is a common problem in the pediatric intensive care unit (PICU) and is associated with extubation failure, longer length of stay, and increased mortality. Infants represent a large proportion of PICU admissions and are at higher risk for PES, making identification and mitigation of factors associated with PES important in this age group.

RESEARCH QUESTION

What factors are associated with PES in infants (age less than 1 year) intubated in the PICU?

STUDY DESIGN & METHODS

The primary outcome was PES as defined by the need for racemic epinephrine within 6 h of extubation. Secondary outcomes were heliox administration and reintubation. Statistical analyses were performed with Fisher's exact test for univariate analyses and multivariate logistic regression.

RESULTS

518 patient charts were retrospectively reviewed. 24.1% of patients developed PES. Duration of mechanical ventilation greater than 48 h was associated with increased risk of PES (odds ratio [OR] = 1.75, 95% confidence interval [CI] 1.13-2.71, P = .01), as was nonelective intubation (OR = 2.92, 95% CI 1.91-4.46, P < .01). The presence of a cuff, gastroesophageal reflux disease, prematurity, and known upper airway abnormality had no association with PES. 4.0 endotracheal tubes (ETTs) had an increased association with PES compared to 3.5 ETTs (OR = 1.96, 95% CI 1.18-3.27, P < .01). There was no difference in risk of PES between 3.5 and 3.0 ETTs.

INTERPRETATION

In infants intubated in the PICU, mechanical ventilation greater than 48 h and nonelective intubation were associated with PES. 4.0 ETTs were associated with higher risk of PES compared to 3.5 ETTs. These findings may help providers in ETT selection and to identify infants that may be at increased risk of PES.

Pre-Extubation Ultrasound Measurement of In Situ Cuffed Endotracheal Tube Laryngeal Air Column Width Difference: Single-Center Pilot Study of Relationship With Post-Extubation Stridor in Subjects Younger Than 5 Years Old

OBJECTIVES

Post-extubation stridor (PES) is difficult to predict before extubation. We therefore evaluated the potential diagnostic performance of pre-extubation laryngeal air column width difference (LACWD) measurement, as assessed by intensivist-performed point-of-care laryngeal ultrasound, in relation to clinically important PES.

DESIGN

Prospective observational cohort study.

SETTING

Single quaternary care PICU (July 19, 2021, to October 31, 2022).

PATIENTS

Included subjects were younger than 5 years old, intubated with a cuffed endotracheal tube, requiring invasive mechanical ventilation for greater than 24 hours, and nearing extubation. Subjects at high risk for supraglottic airway obstruction were excluded.

INTERVENTIONS

Laryngeal ultrasound with measurement of laryngeal air column width with the endotracheal tube cuff inflated and deflated. Clinically important PES was defined as a high-pitched inspiratory respiratory noise suspected to be from a subglottic focus necessitating received medical intervention or reintubation.

MEASUREMENTS AND MAIN RESULTS

Among 53 enrolled subjects, 18 of 53 (34%) experienced PES and three of 53 (6%) were reintubated because of severe subglottic upper airway obstruction. Median LACWD was significantly lower in the stridor group compared with the nonstridor group (∆ 0.41 mm; 95% CI, 0.37-0.48; p < 0.001). The area under the receiver operating characteristic curve for LACWD as a diagnosis of PES was 0.94 (95% CI, 0.89-1.00; p < 0.001). The LACWD cutoff for PES was less than or equal to 0.47 mm, which yielded a diagnostic sensitivity of 91.4% and specificity of 88.9%. In this population, the pre-to-post-test change in probability of PES for LACWD less than or equal to 0.47 mm is 0.34 to 0.81.

CONCLUSIONS

Pre-extubation LACWD is a novel, noninvasive assessment that can be performed and interpreted by the intensivist at the bedside. There is, however, diagnostic uncertainty in the use of this measurement for identifying those at-risk of PES and larger validation studies are needed.

Prevalence, Risk Factors, and Outcomes of Airway Versus Non-Airway Pediatric Extubation Failure

BACKGROUND

Pediatric extubation failure is associated with morbidity and mortality. The most common cause is upper-airway obstruction. Subglottic edema is common, but upper-airway obstruction can occur from the oral cavity to the trachea. Dichotomous categorization of extubation failure as airway versus non-airway may help identify risk factors as well as strategies that translate to lower extubation failure rates.

METHODS

This was as single-center, retrospective cohort study of invasive mechanical ventilation encounters within a quality improvement database between October 1, 2017-November 30, 2020. Utilizing a 3-physician adjudication process, all extubation failures were categorized as airway versus non-airway. Primary outcome was failure subtype prevalence. Secondary outcome was failure subtype risk factors. Clinical outcomes were explored.

RESULTS

The all-cause extubation failure rate was 10% in a cohort of 844 encounters. Airway and non-airway extubation failure represented 60.7% and 39.3%, respectively. Most airway failures were due to upper-airway obstruction (84.3%)-35.3% were supraglottic, 25.5% subglottic, and 23.5% mixed. Other causes of airway failure were airway patency/secretions (11.8%) and aspiration (3.9%). Non-airway failures were attributed to respiratory failure (75.8%), encephalopathy (15.2%), and other (9%). All-cause extubation failure was associated with dysgenetic/syndromic comorbidity (P = .005), ≥ 3 concurrent comorbid conditions (P = .007), indication for invasive ventilation (P < .001), and longer invasive mechanical ventilation duration (P < .001). Airway extubation failure was significantly associated with the presence of a respiratory comorbidity (P = .01) and Glasgow coma scale < 10 (P = .02). No significant non-airway failure risk factors were identified. Longer pediatric ICU (PICU) stay (P < .001) and PICU mortality (P < .001) were associated with all-cause extubation failure. No significant outcome associations with extubation failure subtype were identified.

CONCLUSIONS

Airway extubation failure prevalence was 1.5 times higher than non-airway failure. Potential risk factors for airway failure were identified. These findings are hypothesis generating for future study focused on key evidence gaps and pragmatic bedside application.

Pediatric ventilation liberation: evaluating the role of endotracheal secretions in an extubation readiness bundle

BACKGROUND

An evidence gap exists regarding the role of endotracheal secretions in pediatric extubation decisions. This study aims to evaluate whether endotracheal secretion burden independently correlates with pediatric extubation failure.

METHODS

This is a single-center, prospective cohort study of children aged <19 years requiring intubation. Nurses (RN) and respiratory therapists (RT) independently used a novel secretion assessment score focusing on secretion volume, character, and trend. We hypothesized that the RN and RT secretion scores would not correlate with extubation outcome and inter-rater reliability would be poor.

RESULTS

RN secretion character sub-score (OR 3.3, 95% CI 1.1-11.1, p = 0.048) was independently associated with extubation failure. RN and RT inter-rater reliability was poor (correlation 0.385, 95% CI 0.339-0.429, p < 0.001). A failure prediction model incorporating the RN secretion character sub-score as well as indication for mechanical ventilation and spontaneous breathing trial result demonstrated an area under the receiver operating curve of 0.817 (95% CI 0.730-0.904, p < 0.001).

CONCLUSIONS

In the general pediatric population, the RN assessment of endotracheal secretion character was independently associated with extubation failure. A model incorporating indication for mechanical ventilation, spontaneous breathing result, and RN assessment of endotracheal secretion character demonstrated reasonable accuracy in predicting failure in those clinically selected for extubation.

IMPACT

Development of comprehensive and sensitive extubation readiness bundles are key to balancing the competing risks of prolonged invasive mechanical ventilation duration and extubation failure. Evidence for clinical factors linked to extubation outcomes in children are limited. Endotracheal secretion burden is a common factor considered but has not been studied. This study supports a role for endotracheal secretion burden, as assessed by the bedside nurse, in extubation readiness bundles. Inter-rater reliability with respiratory therapists was poor. A model incorporating other key factors showed good discrimination for extubation outcome and sets the stage for prospective evaluation in the general population and diagnosis-specific subgroups.

Subglottic Post-Extubation Upper Airway Obstruction Is Associated With Long-Term Airway Morbidity in Children

OBJECTIVES

Post-extubation upper airway obstruction is the most common cause of extubation failure in children, but there are few data regarding long-term morbidity. We aim to describe the frequency of long-term airway sequelae in intubated children and determine the association with post-extubation upper airway obstruction.

DESIGN

Retrospective, post hoc analysis of previously identified prospective cohort of children in the pediatric/cardiothoracic ICU at Children's Hospital Los Angeles from July 2012 to April 2015. A single provider blinded to the upper airway obstruction classification reviewed the electronic medical records of all patients in the parent study, before and after the index extubation (extubation during parent study), to identify pre-index and post-index upper airway disease. Primary outcomes were prevalence of newly diagnosed airway anomalies following index extubation.

SETTING

Single center, tertiary, 391-bed children's hospital.

PATIENTS

From the parent study, 327 children younger than 18 years (intubated for at least 12 hr) were included if they received subsequent care (regardless of specialty) after the index extubation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

New airway anomalies were identified in 40 of 327 children (12.2%). Patients labeled with subglottic upper airway obstruction at the index extubation were more likely to be diagnosed with new airway anomalies on subsequent follow-up, receive long-term Otolaryngology follow-up, or receive airway surgery (all p ≤ 0.006). In multivariable modeling, upper airway obstruction as the primary reason for initial intubation (odds ratio, 3.71; CI, 1.50-9.19), reintubation during the index ICU admission (odds ratio, 4.44; CI, 1.67-11.80), pre-index airway anomaly (odds ratio, 3.31; CI, 1.36-8.01), and post-extubation subglottic upper airway obstruction (odds ratio, 3.50; CI, 1.46-8.34) remained independently associated with the diagnosis of new airway anomalies.

CONCLUSIONS

Post-extubation subglottic upper airway obstruction is associated with a three-fold greater odds of long-term airway morbidity. These patients may represent an at-risk population that should be monitored closely after leaving the ICU.

Heliox for croup in children

BACKGROUND

Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (the benefits of which are often delayed) and nebulised epinephrine (adrenaline) (the benefits of which may be short-lived and which can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation. A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress. This review updates versions published in 2010, 2013, and 2018.

OBJECTIVES

To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation.

SEARCH METHODS

We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, CINAHL, Web of Science, and LILACS, on 15 April 2021. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 15 April 2021. We contacted the British Oxygen Company, a leading supplier of heliox.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo, no treatment, or any active intervention(s) in children with croup.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Data that could not be pooled for statistical analysis were reported descriptively.

MAIN RESULTS

We included 3 RCTs involving a total of 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months, and all studies were conducted in emergency departments. Two studies were conducted in the USA and one in Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study because of its open-label design. We did not identify any new trials for this 2021 update. One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70) (Westley croup score, scale range 0 to 16). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low certainty, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported. In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve Taussig croup scores (scale range 0 to 15) at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -1.56 to 0.16). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be a difference in hospitalisation rates between groups (odds ratio 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to imprecision and high risk of bias related to an open-label design. Information on heart rate and intubation was not reported. In the third study, 29 children with moderate to severe croup all received continuous cool mist and intramuscular dexamethasone (0.6 mg/kg). They were then randomised to receive either heliox (given as a mixture of 70% helium and 30% oxygen) plus one to two doses of nebulised saline or 100% oxygen plus nebulised epinephrine (adrenaline), with gas therapy administered continuously for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may result in little or no difference overall using repeated-measures analysis. We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported. The included studies did not report on adverse events, intensive care admissions, or parental anxiety. We could not pool the available data because each comparison included data from only one study.

AUTHORS' CONCLUSIONS

Given the very limited available evidence, uncertainty remains regarding the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate croup treated with dexamethasone. The effect of heliox may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.

Twenty-four-hour pretreatment with low dose (0.25 mg/kg/dose) versus high dose (0.5 mg/kg/dose) dexamethasone in reducing the risk of postextubation airway obstruction in children: A randomized open-label noninferiority trial

OBJECTIVE

Multidose dexamethasone pretreatment reduces risk of postextubation airway obstruction (PEAO). However, its optimal dose is not known. We planned to compare 24 h pretreatment with low-dose dexamethasone (LDD) (0.25 mg/kg/dose) versus high-dose dexamethasone (HDD) (0.5 mg/kg/dose) in reducing risk of PEAO.

DESIGN

Stratified (for age and intubation duration) randomized open-label noninferiority trial.

SETTING

Fifteen-bed pediatric intensive care unit in a lower-middle-income country.

PATIENTS

Children (3 months-12 years) intubated for more than or equal to 48 h and planned for first extubation (February 17-March 19). Upper airway conditions, chronic respiratory diseases, chronic NSAID therapy, steroid, or intravenous immunoglobulin in the last 7 days, presence of gastrointestinal bleeding, hypertension, and hyperglycemia were exclusions.

INTERVENTIONS

LDD (n = 144) or HDD (n = 143) (q6h) for a total of six doses. Extubation was planned immediately after fifth dose. Noninferiority margin was kept at 12% from baseline.

Utility of Endotracheal Tube Cuff Pressure Monitoring in Mechanically Ventilated (MV) Children in Preventing Post-extubation Stridor (PES)

Objective

To study if protocolized monitoring of endotracheal tube (ETT) cuff pressure every 6 hours is better than adjusting endotracheal tube cuff inflation by the only bedside clinical assessment.

Materials and methods

This was a single-center prospective randomized controlled study done between July 1, 2017 and March 31, 2019. Children between 1 month and 18 years, intubated with cuffed ETT by our trained doctors were included. After obtaining consent, patients were randomized into two groups, standard group (SG) and cuff pressure monitoring group (MG). Sample size was calculated with 80 patients in each group with a power of 80%, significance level (alpha 0.05 and beta 0.2). In the SG, ETT cuff inflation was adjusted by clinical assessment (bedside minimal leak technique and monitoring the percentage of leak displayed on ventilator display) at 6 hours interval. In the MG, cuff pressures were monitored by the device every 6 hours to maintain between 20 and 25 mm Hg.

Results

Out of 543 mechanically ventilated children during the study period, 266 were eligible and randomized for study. During the study, 89 patients died and 17 were left against medical advice, leaving 80 patients in each group. Incidence of post-extubation stridor (PES), re-intubation rate, ventilator-associated pneumonia (VAP) rate, ventilator days, and length of pediatric intensive care unit (PICU) stay were analyzed and found no advantage of protocolized monitoring of cuff pressures in the reduction of any of the above variables.

Conclusion

Our findings if confirmed by large multicentric studies can bring an end to routine ETT cuff pressure measurements and emphasize more on clinical assessment. Clinical trial registry (CTRI/2019/05/019098).

Indian Journal of Critical Care Medicine (2021): 10.5005/jp-journals-10071-23737

How to cite this article

Shaikh F, Janaapureddy YR, Mohanty S, Reddy PK, Sachane K, Dekate PS, et al. Utility of Endotracheal Tube Cuff Pressure Monitoring in Mechanically Ventilated (MV) Children in Preventing Post-extubation Stridor (PES). Indian J Crit Care Med 2021;25(2):181–184.

Pre-extubation ultrasonographic measurement of intracricoid peritubal free space: A pilot study to predict post-extubation airway obstruction in children

OBJECTIVE

Post-extubation airway obstruction (PEAO) is common and difficult to predict in children. We hypothesized that Intracricoid Peritubal Free Space (IPFS) obtained by deducting the outer diameter of the endotracheal tube in situ (OD_TT - provided by the manufacturer) from the ultrasonographically measured internal transverse cricoid diameter (ICD_t) is likely to be inversely proportional to the risk of developing PEAO. This prospective observational study was planned to evaluate this hypothesis.

METHODS

This study was conducted in a Pediatric Intensive Care Unit of a tertiary care teaching hospital in a low-middle income economy. Laryngotracheal ultrasound was performed just prior to the first elective extubation in 93 patients (3mo-12yrs) intubated for ≥ 48 h, to calculate the IPFS. Patients with pre-existent upper airway conditions, chronic respiratory diseases and poor airway reflexes were excluded. Patients with Westley's Croup Score (WCS) ≥4 were classified as PEAO, and those with WCS ≥7, as extubation failure (EF).

RESULTS

Thirty-two (34%) patients developed PEAO, while seventeen (18%) developed EF. Baseline clinical characteristics were similar in patients with and without PEAO. IPFS was lesser in patients who developed PEAO (4.16 ± 1.18 mm vs. 5.28 ± 1.51 mm, p < 0.001) and EF (4.13 ± 1.44 mm vs. 5.07 ± 1.46 mm, p = 0.019) compared to those who did not. IPFS <5.16 mm predicted PEAO [sensitivity, 84%; positive predictive value (PPV), 87%; AUC, 0.714), while IPFS <3.77 mm predicted EF (specificity, 80%; PPV, 88%; AUC, 0.679). Combining clinical risk factors (presence of clinical edema, prolonged ventilation and younger age) and lesser IPFS helped develop a clinico-sonographic prediction model with improved predictability for PEAO and EF (AUC, 0.820 for both).

CONCLUSIONS

Lesser IPFS is reasonably sensitive and specific to predict PEAO and EF respectively with high PPV. Combining clinical risk factors and IPFS improved the PPV further. Further studies with larger samples stratified for different age groups in different clinical settings are required to confirm these observations.

Initial radiographic tracheal ratio in predicting clinical outcomes in croup in children

Croup is the leading infectious disease resulting in pediatric upper airway obstruction. Our purpose is to analyze diverse features of neck radiographs could be seen as an objective tool to predict outcomes in patients with croup. One hundred and ninety-two patients were prospectively recruited in pediatric emergency department with diagnosis of croup. The initial Westley score (WS), presence of steeple sign, extent of narrowing, and narrowing ratio on soft tissue neck radiographs were determined before and after treatments. The extent of frontal narrowing, extent of lateral narrowing, frontal ratio (FR), and lateral ratio (LR) were investigated to predict clinical outcomes in patients with croup. The extent of frontal/lateral narrowing and LR had significant correlation with outpatient status. Almost 71% of patients with FR values below 0.23 stayed in the hospital longer, whereas nearly 98% of patients with FR vales above 0.65 could be discharged. About 85% of patients with LR below 0.45 hospitalized longer. The LR and FR were significantly correlated with the severity and admission rate in croup. The LR > 0.6 and FR > 0.65 may indicate low risk in patients with croup, whereas the FR < 0.23 or LR < 0.45 may indicate the need of stay in hospital for further treatment and monitor.

Interobserver Agreement on Clinical Judgment of Work of Breathing in Spontaneously Breathing Children in the Pediatric Intensive Care Unit

Clinical assessment of the work of breathing (WOB) remains a cornerstone in respiratory support decision-making in the pediatric intensive care unit (PICU). In this study, we determined the interobserver agreement of 30 observers (PICU physicians and nurses) on WOB and multiple signs of effort of breathing in 10 spontaneously breathing children admitted to the PICU. By reliability analysis, the agreement on overall WOB was poor to moderate, and only three separate signs of effort of breathing (breathing rate, stridor, and grunting) showed moderate-to-good interobserver reliability. We conclude that the interobserver agreement on the clinical WOB judgment among PICU physicians and nurses is low.

Derivation and Validation of an Objective Effort of Breathing Score in Critically Ill Children

OBJECTIVES

To derive and validate a score that correlates with an objective measurement of a child's effort of breathing.

DESIGN

Secondary analysis of a previously conducted observational study.

SETTING

The pediatric and cardiothoracic ICUs of a quaternary-care children's hospital.

PATIENTS

Patients more than 37 weeks gestational age to age 18 years who were undergoing extubation.

INTERVENTIONS

Effort of breathing was measured in patients following extubation using esophageal manometry to calculate pressure rate product. Simultaneously, members of a multidisciplinary team (nurse, physician, and respiratory therapist) assessed respiratory function using a previously validated tool. Elements of the tool that were significantly associated with pressure rate product in univariate analysis were identified and included in a multivariate model. An Effort of Breathing score was derived from the results of the model using data from half of the subjects (derivation cohort) and then validated using data from the remaining subjects (validation cohort) by calculating the area under the receiver operator characteristic curve for pressure rate product greater than 90th percentile and for the need for reintubation.

MEASUREMENTS AND MAIN RESULTS

Among 409 subjects, the median age was 5 months, and nearly half were cardiac surgery patients (49.1%). Retractions, stridor, and pulsus paradoxus were included in the Simple Score. Area under the receiver operator characteristic curve for pressure rate product greater than 90th percentile was 0.8359 (95% CI, 0.7996-0.8722) in the derivation cohort and 0.7930 (0.7524-0.8337) in the validation cohort. Area under the receiver operator characteristic curve for reintubation was 0.7280 (0.6807-0.7752) when all scores were analyzed individually and was 0.7548 (0.6644-0.8452) if scores from three clinicians from different disciplines were summated. Results were similar regardless of provider discipline or training.

CONCLUSIONS

A scoring system was derived and validated, performed acceptably to predict increased effort of breathing or need for advanced respiratory support and may function best when used by a team.

Heliox for croup in children

BACKGROUND

Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (from which benefits are often delayed) and nebulised epinephrine (adrenaline) (which may be short-lived and can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation.A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress.This review updates versions published in 2010 and 2013.

OBJECTIVES

To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment, on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation.

SEARCH METHODS

We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group's Specialised Register; MEDLINE; Embase; CINAHL; Web of Science; and LILACS in January and February 2018. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 8 February 2018. We contacted British Oxygen Company, a leading supplier of heliox (BOC Australia 2017).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo or any active intervention(s) in children with croup.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We reported data that could not be pooled for statistical analysis descriptively.

MAIN RESULTS

We included 3 RCTs with 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months; all studies were conducted in emergency departments in the USA (two studies) and Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study due to an open-label design. We added no new trials for this update.One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low quality, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported.In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve croup scores at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -4.86 to 3.46). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be no difference in hospitalisation rates between groups (OR 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low quality, downgraded due to imprecision and high risk of bias related to open-label design. Information on heart rate and intubation was not reported.In the third study, 29 children with moderate to severe croup received intramuscular dexamethasone (0.6 mg/kg) and either heliox with one to two doses of nebulised saline, or 100% oxygen with one to two doses of adrenaline for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may have little or no difference overall using repeated measures analysis. We assessed the evidence for all outcomes in this comparison as of low quality, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported.The included studies did not report on adverse events, intensive care admissions, or parental anxiety.We could not pool the available data because each comparison included data from only one study.

AUTHORS' CONCLUSIONS

Due to very limited evidence, uncertainty remains about the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate to severe croup treated with dexamethasone. The effect may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.

A Systematic Review and Comprehensive Critical Analysis Examining the Use of Prednisolone for the Treatment of Mild to Moderate Croup

Background:

Many randomised control trials and systematic reviews have examined the benefits of glucocorticoids for the treatment of croup in children, but they have reported mainly on dexamethasone as an oral treatment for croup. No systematic reviews have examined prednisolone alone.

Aim:

To determine in a systematic review of the literature whether a single dose of oral prednisolone is as effective as a single dose of dexamethasone for reducing croup symptoms in children.

Search Strategy:

A detailed search was conducted on the following databases: CINAHL, MEDLINE EBSCO, MEDLINE, OVID, PubMed, The Cochrane Library, ProQuest, EMBASE, JBI, Sum search, and OpenGrey. Study authors were contacted.

Selection Criteria:

Randomised Controlled Trials, clinical trials or chart reviews which examined children with croup who were treated with prednisolone alone, or when prednisolone was compared to a dexamethasone treatment and the effectiveness of the intervention was objectively measured using croup scores and re-attendance as primary outcomes.

Data Collection and Analysis:

Following PRISMA guidelines for systematic reviews, relevant studies were identified. Scores were graded agreed by two independent reviewers using QualSyst.

Main Results:

Four studies met the inclusion criteria, but were too heterogeneous to combine in statistical meta-analysis. The result suggests that although prednisolone appears as effective as dexamethasone when first given, it is less so for preventing re-presentation. Trial sample sizes were small, making firm conclusions difficult, however, a second dose of prednisolone the following day may be useful. More research including cost-benefit analysis is needed to examine the efficacy of prednisolone compared to dexamethasone.

Clinical respiratory scales: which one should we use?

INTRODUCTION

There are countless clinical respiratory scales for acute dyspnoea. Most healthcare professionals choose one based on previous personal experience or following local practice, unaware of the implications of their choice. The lack of critical comparisons between those different tools has been a widespread problem that only recently has begun to be addressed via score validation studies. Here we try to assess and compare the quality criteria of measurement properties of acute dyspnoea scores. Areas covered: A literature review was conducted by searching the PubMed database. Forty-five documents were deemed eligible as they reported the use or building of clinical scales, using at least two parameters, and applied these to an acute episode of respiratory dyspnoea. Our primary focus was the description of the validity, reliability and utility of 41 suitable scoring instruments. Differences in sample selection, study design, rater profiles and potential methodological shortcomings were also addressed. Expert commentary: All acute dyspnoea scores lack complete validation. In particular, the areas of measurement error and interpretability have not been addressed correctly by any of the tools reviewed. Frequent modification of pre-existing scores (in items composition and/or name), differences in study design and discrepancies in reviewed sources also hinder the search for an adequate tool.

Westley score and clinical factors in predicting the outcome of croup in the pediatric emergency department

BACKGROUND

Westley croup score has been generally used to assess the severity of croup. This study aimed to identify the individual factors associated with Westley score (WS) and other clinical factors in predicting the outcomes in the pediatric emergency department (PED).

POPULATION AND METHOD

We prospectively recruited patients with croup from the PED. The individual factors of WS, fever, age, and the length of hospital stay were analyzed to predict clinical outcomes. We calculated all the areas under the receiver operating characteristic (ROC) curve to determine the cutoff values of initial WS discriminating the need for admission to the wards.

RESULT

A total of 192 patients with croup were enrolled. Cyanosis and altered consciousness were not clinically significant even in patients with severe croup, whereas retraction and air entry were the major factors in WS for predicting clinical outcomes. The initial WS had a strong correlation with the length of hospital stay (r = 0.617, P < 0.001). ROC analysis showed that patients with an initial WS <2 (sensitivity, 5%; specificity, 100%; LR⁺ , 1.05; LR^- , 0; AUC, 0.87) were discharged home while the patients with an initial WS ≥5 (sensitivity, 99%; specificity, 57%; LR⁺ , 41.0; LR^- , 0.43) were more likely to require to stay in the PED. Patients with an WS ≥6 were more likely to be admitted to the wards (sensitivity, 97%; specificity, 47%; LR⁺ , 416.35; LR^- , 0.54; AUC, 0.90) CONCLUSION: Patients with an initial WS of 1-2 could be safely treated at home and those with initial WS >5 required hospitalization for further treatment.

Post-extubation stridor in Respiratory Syncytial Virus bronchiolitis: Is there a role for prophylactic dexamethasone?

Aim

The purpose of this study was to determine the incidence of reintubation due to upper airway obstruction in a homogeneous group of ventilated infants with Respiratory Syncytial Virus bronchiolitis. Our secondary objective was to determine whether prophylactic administration of dexamethasone prior to extubation was associated with decreased risk of reintubation.

Methods

This retrospective observational study in two Pediatric Intensive Care Units in 2 university hospitals in The Netherlands included two hundred patients younger than 13 months admitted with respiratory insufficiency caused by Respiratory Syncytial Virus bronchiolitis, requiring invasive mechanical ventilation. A logistic regression analysis with propensity score method was used to adjust for possible confounding.

Results

Reintubation due to post-extubation stridor occurred in 17 (8.5%) of 200 patients. After propensity score matching, administration of dexamethasone prior to extubation was associated with a significantly (p = 0.0011) decreased risk of reintubation due to post-extubation stridor compared to patients not receiving prophylactic dexamethasone (absolute risk reduction 13%, 95% CI 5.3–21%).

Conclusion

Reintubation due to post-extubation stridor is an important complication of ventilation for Respiratory Syncytial Virus bronchiolitis. Dexamethasone administered prior to extubation probably reduces the risk of post-extubation stridor necessitating reintubation in these infants. The results of this study support initiation of a placebo-controlled trial to confirm the beneficial effect of prophylactic dexamethasone.

Impact of monitoring endotracheal tube cuff leak pressure on postextubation stridor in children

PURPOSE

To determine if implementing a protocol maintaining an air leak when using cuffed endotracheal tubes (ETT) throughout the course of mechanical ventilation (MV) in children would decrease the rate of postextubation stridor (PES).

METHODS

All children requiring MV through a cuffed ETT were included, except those with (1) upper airway anomaly, (2) died while on MV, (3) received tracheostomy before extubation, and (4) transferred before extubation. We implemented a protocol limiting the volume of air instilled into the cuff, allowing an air leak by 25 cm H₂O pressure or by peak inspiratory pressure, whichever was higher. Monitoring occurred every 6 hours, adjusting cuff volumes if necessary. Patients receiving nebulized racemic epinephrine within 24 hours of extubation for upper airway obstruction were defined as having PES.

RESULTS

At baseline, 110 patients received cuffed ETTs. The proportion of patients who had an air leak at the time of extubation was 47.3%, and that who developed PES was 21.8%. During the intervention, 101 patients received cuffed ETTs. Most (72.3%) had an air leak at the time of extubation (P< .01), and 9.9% developed PES, a 54.6% relative decrease (relative risk, 0.45; 95% confidence interval, 0.22-0.90; P= .018).

CONCLUSIONS

Maintaining an appropriate air leak throughout the course of MV using cuffed ETT decreases the rate of PES in children.

Evaluating Risk Factors for Pediatric Post-extubation Upper Airway Obstruction Using a Physiology-based Tool

RATIONALE

Subglottic edema is the most common cause of pediatric extubation failure, but few studies have confirmed risk factors or prevention strategies. This may be due to subjective assessment of stridor or inability to differentiate supraglottic from subglottic disease.

OBJECTIVES

Objective 1 was to assess the utility of calibrated respiratory inductance plethysmography (RIP) and esophageal manometry to identify clinically significant post-extubation upper airway obstruction (UAO) and differentiate subglottic from supraglottic UAO. Objective 2 was to identify risk factors for subglottic UAO, stratified by cuffed versus uncuffed endotracheal tubes (ETTs).

METHODS

We conducted a single-center prospective study of children receiving mechanical ventilation. UAO was defined by inspiratory flow limitation (measured by RIP and esophageal manometry) and classified as subglottic or supraglottic based on airway maneuver response. Clinicians performed simultaneous blinded clinical UAO assessment at the bedside.

MEASUREMENTS AND MAIN RESULTS

A total of 409 children were included, 98 of whom had post-extubation UAO and 49 (12%) of whom were subglottic. The reintubation rate was 34 (8.3%) of 409, with 14 (41%) of these 34 attributable to subglottic UAO. Five minutes after extubation, RIP and esophageal manometry better identified patients who subsequently received UAO treatment than clinical UAO assessment (P < 0.006). Risk factors independently associated with subglottic UAO included low cuff leak volume or high preextubation leak pressure, poor sedation, and preexisting UAO (P < 0.04) for cuffed ETTs; and age (range, 1 mo to 5 yr) for uncuffed ETTs (P < 0.04). For uncuffed ETTs, the presence or absence of preextubation leak was not associated with subglottic UAO.

CONCLUSIONS

RIP and esophageal manometry can objectively identify subglottic UAO after extubation. Using this technique, preextubation leak pressures or cuff leak volumes predict subglottic UAO in children, but only if the ETT is cuffed.

Risk factors for post-extubation stridor in children: the role of orotracheal cannula

Objective

To determine the risk factors associated with stridor, with special attention to the role of the cuffed orotracheal cannula.

Methods

Prospective analysis of all the intubated patients submitted to mechanical ventilator support from January 2008 to April 2011. The relevant factors for stridor collected were age, weight, size and type of airway tube, diagnosis, and duration of mechanical ventilation. The effects of variables on stridor were evaluated using uni- and multivariate logistic regression models.

Results

A total of 136 patients were included. Mean age was 1.4 year (3 days to 17 years). The mean duration of mechanical ventilation was 73.5 hours. Fifty-six patients (41.2%) presented with stridor after extubation. The total reintubation rate was 19.6% and 12.5 in patients with and without stridor, respectively. The duration of mechanical ventilation (>72 hours) was associated with a greater risk for stridor (odds ratio of 8.60; 95% confidence interval of 2.98-24.82; p<0.001). The presence of the cuffed orotracheal cannula was not associated with stridor (odds ratio of 98; 95% confidence interval of 0.46-2.06; p=0.953).

Conclusion

The main risk factor for stridor after extubation in our population was duration of mechanical ventilation. The presence of the cuffed orotracheal cannula was not associated with increased risk for stridor, reinforcing the use of the cuffed orotracheal cannula in children with respiratory distress.

Respiratory inductance plethysmography calibration for pediatric upper airway obstruction: an animal model

BACKGROUND

We sought to determine optimal methods of respiratory inductance plethysmography (RIP) flow calibration for application to pediatric postextubation upper airway obstruction.

METHODS

We measured RIP, spirometry, and esophageal manometry in spontaneously breathing, intubated Rhesus monkeys with increasing inspiratory resistance. RIP calibration was based on: ΔµV(ao) ≈ M[ΔµV(RC) + K(ΔµV(AB))] where K establishes the relationship between the uncalibrated rib cage (ΔµV(RC)) and abdominal (ΔµV(AB)) RIP signals. We calculated K during (i) isovolume maneuvers during a negative inspiratory force (NIF), (ii) quantitative diagnostic calibration (QDC) during (a) tidal breathing, (b) continuous positive airway pressure (CPAP), and (c) increasing degrees of upper airway obstruction (UAO). We compared the calibrated RIP flow waveform to spirometry quantitatively and qualitatively.

RESULTS

Isovolume calibrated RIP flow tracings were more accurate (against spirometry) both quantitatively and qualitatively than those from QDC (P < 0.0001), with bigger differences as UAO worsened. Isovolume calibration yielded nearly identical clinical interpretation of inspiratory flow limitation as spirometry.

CONCLUSION

In an animal model of pediatric UAO, isovolume calibrated RIP flow tracings are accurate against spirometry. QDC during tidal breathing yields poor RIP flow calibration, particularly as UAO worsens. Routine use of a NIF maneuver before extubation affords the opportunity to use RIP to study postextubation UAO in children.