Progression of Respiratory Support Following Pediatric Extubation

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.

A 30-Minute Spontaneous Breathing Trial Misses Many Children Who Go On to Fail a 120-Minute Spontaneous Breathing Trial

BACKGROUND

The optimal length of spontaneous breathing trials (SBTs) in children is unknown.

RESEARCH QUESTIONS

What are the most common reasons for SBT failure in children, and when do they occur? Can clinical parameters at the 30-min mark of a 120-min SBT predict outcome?

STUDY DESIGN AND METHODS

We performed a secondary analysis of a clinical trial in pediatric ARDS, in which 2-h SBTs are conducted daily. SBT failure is based on objective criteria, including esophageal manometry for effort of breathing, categorized as passage, early failure (≤ 30 min), or late failure (30-120 min). Spirometry was used to calculate respiratory rate (RR), tidal volume (Vt), and rapid shallow breathing index (RSBI), in addition to pulse oximetry and capnography. Predictive models evaluated parameters at 30 min against SBT outcome, using receiver operating characteristic plots and area under the curve.

RESULTS

We included 100 children and 305 SBTs, with 42% of SBTs being successful, 32% failing within 30 min, and 25% failing between 30 and 120 min. Of the patients passing SBTs at 30 min, 40% went on to fail by 120 min. High respiratory effort (esophageal manometry) was present in > 80% of failed SBTs. At the 30-min mark, there were no clear thresholds for RR, Vt, RSBI, Fio2, oxygen saturation, or capnography that could reliably predict SBT outcome. Multivariable modeling identified RR (P < .001) and RSBI > 7 (P = .034) at 30 min, pre-SBT inspiratory pressure level (P = .009), and pre-SBT retractions (P = .042) as predictors for SBT failure, but this model performed poorly in an independent validation set with the receiver operating characteristic plot crossing the reference line (area under the curve, 0.67).

INTERPRETATION

A 30-min SBT may be too short in children recovering from pediatric ARDS because many go on to fail between 30 and 120 min. Reassuring values of Vt, RR, and gas exchange at 30 min do not reliably predict SBT passage at 2 h, likely because they do not capture the effort of breathing.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03266016; URL: www.

CLINICALTRIALS

gov.

Executive Summary: International Clinical Practice Guidelines for Pediatric Ventilator Liberation, A Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Document

Rationale: Pediatric-specific ventilator liberation guidelines are lacking despite the many studies exploring elements of extubation readiness testing. The lack of clinical practice guidelines has led to significant and unnecessary variation in methods used to assess pediatric patients' readiness for extubation. Methods: Twenty-six international experts comprised a multiprofessional panel to establish pediatrics-specific ventilator liberation clinical practice guidelines, focusing on acutely hospitalized children receiving invasive mechanical ventilation for more than 24 hours. Eleven key questions were identified and first prioritized using the Modified Convergence of Opinion on Recommendations and Evidence. A systematic review was conducted for questions that did not meet an a priori threshold of ⩾80% agreement, with Grading of Recommendations, Assessment, Development, and Evaluation methodologies applied to develop the guidelines. The panel evaluated the evidence and drafted and voted on the recommendations. Measurements and Main Results: Three questions related to systematic screening using an extubation readiness testing bundle and a spontaneous breathing trial as part of the bundle met Modified Convergence of Opinion on Recommendations criteria of ⩾80% agreement. For the remaining eight questions, five systematic reviews yielded 12 recommendations related to the methods and duration of spontaneous breathing trials, measures of respiratory muscle strength, assessment of risk of postextubation upper airway obstruction and its prevention, use of postextubation noninvasive respiratory support, and sedation. Most recommendations were conditional and based on low to very low certainty of evidence. Conclusions: This clinical practice guideline provides a conceptual framework with evidence-based recommendations for best practices related to pediatric ventilator liberation.

Predictive parameters and model for extubation outcome in pediatric patients

Background

Prolonged mechanical ventilation is associated with significant morbidity in critically ill pediatric patients. In addition, extubation failure and deteriorating respiratory status after extubation contribute to increased morbidity. Well-prepared weaning procedures and accurate identification of at-risk patients using multimodal ventilator parameters are warranted to improve patient outcomes. This study aimed to identify and assess the diagnostic accuracy of single parameters and to develop a model that can help predict extubation outcomes.

Materials and methods

This prospective observational study was conducted at a university hospital between January 2021 and April 2022. Patients aged 1 month to 15 years who were intubated for more than 12 h and deemed clinically ready for extubation were enrolled. A weaning process with a spontaneous breathing trial (SBT), with or without minimal setting, was employed. The ventilator and patient parameters during the weaning period at 0, 30, and 120 min and right before extubation were recorded and analyzed.

Results

A total of 188 eligible patients were extubated during the study. Of them, 45 (23.9%) patients required respiratory support escalation within 48 h. Of 45, 13 (6.9%) were reintubated. The predictors of respiratory support escalation consisted of a nonminimal-setting SBT [odds ratio (OR) 2.2 (1.1, 4.6), P = 0.03], >3 ventilator days [OR 2.4 (1.2, 4.9), P = 0.02], occlusion pressure (P0.1) at 30 min ≥0.9 cmH₂O [OR 2.3 (1.1, 4.9), P = 0.03], and exhaled tidal volume per kg at 120 min ≤8 ml/kg [OR 2.2 (1.1, 4.6), P = 0.03]; all of these predictors had an area under the curve (AUC) of 0.72. A predictive scoring system to determine the probability of respiratory support escalation was developed using a nomogram.

Conclusion

The proposed predictive model, which integrated both patient and ventilator parameters, showed a modest performance level (AUC 0.72); however, it could facilitate the process of patient care.

Operational Definitions Related to Pediatric Ventilator Liberation

BACKGROUND

Common, operational definitions are crucial to assess interventions and outcomes related to pediatric mechanical ventilation. These definitions can reduce unnecessary variability among research and quality improvement efforts, to ensure findings are generalizable, and can be pooled to establish best practices.

RESEARCH QUESTION

Can we establish operational definitions for key elements related to pediatric ventilator liberation using a combination of detailed literature review and consensus-based approaches?

STUDY DESIGN AND METHODS

A panel of 26 international experts in pediatric ventilator liberation, two methodologists, and two librarians conducted systematic reviews on eight topic areas related to pediatric ventilator liberation. Through a series of virtual meetings, we established draft definitions that were voted upon using an anonymous web-based process. Definitions were revised by incorporating extracted data gathered during the systematic review and discussed in another consensus meeting. A second round of voting was conducted to confirm the final definitions.

RESULTS

In eight topic areas identified by the experts, 16 preliminary definitions were established. Based on initial discussion and the first round of voting, modifications were suggested for 11 of the 16 definitions. There was significant variability in how these items were defined in the literature reviewed. The final round of voting achieved ≥ 80% agreement for all 16 definitions in the following areas: what constitutes respiratory support (invasive mechanical ventilation and noninvasive respiratory support), liberation and failed attempts to liberate from invasive mechanical ventilation, liberation from respiratory support, duration of noninvasive respiratory support, total duration of invasive mechanical ventilation, spontaneous breathing trials, extubation readiness testing, 28 ventilator-free days, and planned vs rescue use of post-extubation noninvasive respiratory support.

INTERPRETATION

We propose that these consensus-based definitions for elements of pediatric ventilator liberation, informed by evidence, be used for future quality improvement initiatives and research studies to improve generalizability and facilitate comparison.

Commentary on the First-Line Support for Assistance in Breathing in Children Trials on Noninvasive Respiratory Support: Taking a Closer Look

Noninvasive respiratory support modalities such as high-flow nasal cannula (HFNC) therapy and continuous positive airway pressure (CPAP) are used frequently in pediatric critical care to support acutely ill children with respiratory failure (step-up management) and children following extubation (step-down management). Although there are several observational studies and database analyses comparing the efficacy of HFNC and CPAP, and a few small randomized clinical trials (RCTs), until recently, there were no large RCTs comparing the two modalities in a mixed group of critically ill children. In the first half of 2022, results from the First-Line Support for Assistance in Breathing in Children (FIRST-ABC) trials were published; these comprised a master protocol of two trials: one in acutely ill children (step-up RCT) and one in extubated children (step-down RCT). Each of these pragmatic trials randomized 600 children to either HFNC or CPAP when the treating clinician decided that noninvasive respiratory support beyond standard oxygen therapy was required. The primary outcome was time to liberation from all forms of respiratory support (invasive and noninvasive), excluding supplemental oxygen. The FIRST-ABC trials represent a significant advance in the field of noninvasive respiratory support, which has traditionally been evidence-poor and associated with considerable variability in clinical practice. In this article, we provide an overview of how the FIRST-ABC trials were conceived and conducted, our view on the results, and how the trial findings have changed our clinical practice.

Commentary on High-Flow Nasal Cannula and Continuous Positive Airway Pressure Practices After the First-Line Support for Assistance in Breathing in Children Trials

Continuous positive airway pressure (CPAP) and heated humidified high-flow nasal cannula (HFNC) are commonly used to treat children admitted to the PICU who require more respiratory support than simple oxygen therapy. Much has been published on these two treatment modalities over the past decade, both in Pediatric Critical Care Medicine (PCCM ) and elsewhere. The majority of these studies are observational analyses of clinical, administrative, or quality improvement datasets and, therefore, are only able to establish associations between exposure to treatment and outcomes, not causation. None of the initial randomized clinical trials comparing HFNC and CPAP were definitive due to their relatively small sample sizes with insufficient power for meaningful clinical outcomes (e.g., escalation to bilevel noninvasive ventilation or intubation, duration of PICU-level respiratory support, mortality) and often yielded ambiguous findings or conflicting results. The recent publication of the First-Line Support for Assistance in Breathing in Children (FIRST-ABC) trials represented a major step toward understanding the role of CPAP and HFNC use in critically ill children. These large, pragmatic, randomized clinical trials examined the efficacy of CPAP and HFNC either for "step up" (i.e., escalation in respiratory support) during acute respiratory deterioration or for "step down" (i.e., postextubation need for respiratory support) management. This narrative review examines the body of evidence on HFNC published in PCCM , contextualizes the findings of randomized clinical trials of CPAP and HFNC up to and including the FIRST-ABC trials, provides guidance to PICU clinicians on how to implement the literature in current practice, and discusses remaining knowledge gaps and future research priorities.

Developing an Extubation strategy for the difficult pediatric airway-Who, when, why, where, and how?

Comprehensive airway management of the pediatric patient with a difficult airway requires a plan for the transition back to a patent and protected airway. Multiple techniques are available to manage the periextubation period. Equally important is performing a comprehensive risk assessment and developing a strategy that optimizes the likelihood of safe extubation. This includes team-focused communication of the desired goals, critical steps in the process, and potential responses in the case of failed extubation. This review summarizes extubation of pediatric patients with difficult airways along with one suggested framework to manage this challenging period.

Effect of High-Flow Nasal Cannula Therapy vs Continuous Positive Airway Pressure Following Extubation on Liberation From Respiratory Support in Critically Ill Children: A Randomized Clinical Trial

IMPORTANCE

The optimal first-line mode of noninvasive respiratory support following extubation of critically ill children is not known.

OBJECTIVE

To evaluate the noninferiority of high-flow nasal cannula (HFNC) therapy as the first-line mode of noninvasive respiratory support following extubation, compared with continuous positive airway pressure (CPAP), on time to liberation from respiratory support.

DESIGN, SETTING, AND PARTICIPANTS

This was a pragmatic, multicenter, randomized, noninferiority trial conducted at 22 pediatric intensive care units in the United Kingdom. Six hundred children aged 0 to 15 years clinically assessed to require noninvasive respiratory support within 72 hours of extubation were recruited between August 8, 2019, and May 18, 2020, with last follow-up completed on November 22, 2020.

INTERVENTIONS

Patients were randomized 1:1 to start either HFNC at a flow rate based on patient weight (n = 299) or CPAP of 7 to 8 cm H2O (n = 301).

MAIN OUTCOMES AND MEASURES

The primary outcome was time from randomization to liberation from respiratory support, defined as the start of a 48-hour period during which the child was free from all forms of respiratory support (invasive or noninvasive), assessed against a noninferiority margin of an adjusted hazard ratio (HR) of 0.75. There were 6 secondary outcomes, including mortality at day 180 and reintubation within 48 hours.

RESULTS

Of the 600 children who were randomized, 553 children (HFNC, 281; CPAP, 272) were included in the primary analysis (median age, 3 months; 241 girls [44%]). HFNC failed to meet noninferiority, with a median time to liberation of 50.5 hours (95% CI, 43.0-67.9) vs 42.9 hours (95% CI, 30.5-48.2) for CPAP (adjusted HR, 0.83; 1-sided 97.5% CI, 0.70-∞). Similar results were seen across prespecified subgroups. Of the 6 prespecified secondary outcomes, 5 showed no significant difference, including the rate of reintubation within 48 hours (13.3% for HFNC vs 11.5 % for CPAP). Mortality at day 180 was significantly higher for HFNC (5.6% vs 2.4% for CPAP; adjusted odds ratio, 3.07 [95% CI, 1.1-8.8]). The most common adverse events were abdominal distension (HFNC: 8/281 [2.8%] vs CPAP: 7/272 [2.6%]) and nasal/facial trauma (HFNC: 14/281 [5.0%] vs CPAP: 15/272 [5.5%]).

CONCLUSIONS AND RELEVANCE

Among critically ill children requiring noninvasive respiratory support following extubation, HFNC compared with CPAP following extubation failed to meet the criterion for noninferiority for time to liberation from respiratory support.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN60048867.