A spontaneous breathing trial with pressure support overestimates readiness for extubation in children

Evaluation of renal near-infrared spectroscopy for predicting extubation outcomes in the pediatric intensive care setting

Background

In pediatric intensive care units, extubation failure following invasive mechanical ventilation poses significant health risks. Determining readiness for extubation in children can minimize associated morbidity and mortality. This study investigates the potential role of renal near-infrared spectroscopy (RrSO2) in predicting extubation failure in pediatric patients.

Methods

A total of 84 patients aged between 1 month and 18 years, mechanically ventilated for at least 24 h, were included in this prospective study. RrSO2 levels were measured using near-infrared spectroscopy before and during an extubation readiness test (ERT). The primary outcome measure was extubation failure, defined as a need for reintubation within 48 h.

Results

Of the 84 patients, 71 (84.6%) were successfully extubated, while 13 (15.4%) failed extubation. RrSO2 was found to be lower in the failed extubation group, also decrease in RrSO2 values during ERT was significantly greater in patients with extubation failure. ROC analysis indicated a decrease in ΔRrSO2 of more than 6.15% from baseline as a significant predictor of extubation failure, with a sensitivity of 0.984 and a specificity of 0.889.

Conclusion

Monitoring changes in RrSO2 values may serve as a helpful tool to predict extubation failure in pediatric patients. Further multi-center research is warranted to improve the generalizability and reliability of these findings.

Tests and Indices Predicting Extubation Failure in Children: A Systematic Review and Meta-analysis

INTRODUCTION

There is lack of consensus on what constitutes best practice when assessing extubation readiness in children. This systematic review aims to synthesize data from existing literature on pre-extubation assessments and evaluate their diagnostic accuracies in predicting extubation failure (EF) in children.

METHODS

A systematic search in PubMed, EMBASE, Web of Science, CINAHL, and Cochrane was performed from inception of each database to 15 July 2021. Randomized controlled trials or observational studies that studied the association between pre-extubation assessments and extubation outcome in the pediatric intensive care unit population were included. Meta-analysis was performed for studies that report diagnostic tests results of a combination of parameters.

RESULTS

In total, 41 of 11,663 publications screened were included (total patients, n = 8111). Definition of EF across studies was heterogeneous. Fifty-five unique pre-extubation assessments were identified. Parameters most studied were: respiratory rate (RR) (13/41, n = 1945), partial pressure of arterial carbon dioxide (10/41, n = 1379), tidal volume (13/41, n = 1945), rapid shallow breathing index (RBSI) (9/41, n = 1400), and spontaneous breathing trials (SBT) (13/41, n = 5652). Meta-analysis shows that RSBI, compliance rate oxygenation pressure (CROP) index, and SBT had sensitivities ranging from 0.14 to 0.57. CROP index had the highest sensitivity [0.57, 95% confidence interval (CI) 0.4-0.73] and area under curve (AUC, 0.98). SBT had the highest specificity (0.93, 95% CI 0.92-0.94).

CONCLUSIONS

Pre-extubation assessments studied thus far remain poor predictors of EF. CROP index, having the highest AUC, should be further explored as a predictor of EF. Standardizing the EF definition will allow better comparison of pre-extubation assessments.

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.

Clinical Challenges in Pediatric Ventilation Liberation: A Meta-Narrative Review

OBJECTIVES

To map the evidence for ventilation liberation practices in pediatric respiratory failure using the Realist And MEta-narrative Evidence Syntheses: Evolving Standards publication standards.

DATA SOURCES

CINAHL, MEDLINE, COCHRANE, and EMBASE. Trial registers included the following: ClinicalTrials.gov, European Union clinical trials register, International Standardized Randomized Controlled Trial Number register.

STUDY SELECTION

Abstracts were screened followed by review of full text. Articles published in English language incorporating a heterogeneous population of both infants and older children were assessed.

DATA EXTRACTION

None.

DATA SYNTHESIS

Weaning can be considered as the process by which positive pressure is decreased and the patient becomes increasingly responsible for generating the energy necessary for effective gas exchange. With the growing use of noninvasive respiratory support, extubation can lie in the middle of the weaning process if some additional positive pressure is used after extubation, while for some extubation may constitute the end of weaning. Testing for extubation readiness is a key component of the weaning process as it allows the critical care practitioner to assess the capability and endurance of the patient's respiratory system to resume unassisted ventilation. Spontaneous breathing trials (SBTs) are often seen as extubation readiness testing (ERT), but the SBT is used to determine if the patient can maintain adequate spontaneous ventilation with minimal ventilatory support, whereas ERT implies the patient is ready for extubation.

CONCLUSIONS

Current literature suggests using a structured approach that includes a daily assessment of patient's readiness to extubate may reduce total ventilation time. Increasing evidence indicates that such daily assessments needs to include SBTs without added pressure support. Measures of elevated load as well as measures of impaired respiratory muscle capacity are independently associated with extubation failure in children, indicating that these should also be assessed as part of ERT.

Prediction of extubation failure in the paediatric cardiac ICU using machine learning and high-frequency physiologic data

BACKGROUND

Cardiac intensivists frequently assess patient readiness to wean off mechanical ventilation with an extubation readiness trial despite it being no more effective than clinician judgement alone. We evaluated the utility of high-frequency physiologic data and machine learning for improving the prediction of extubation failure in children with cardiovascular disease.

METHODS

This was a retrospective analysis of clinical registry data and streamed physiologic extubation readiness trial data from one paediatric cardiac ICU (12/2016-3/2018). We analysed patients' final extubation readiness trial. Machine learning methods (classification and regression tree, Boosting, Random Forest) were performed using clinical/demographic data, physiologic data, and both datasets. Extubation failure was defined as reintubation within 48 hrs. Classifier performance was assessed on prediction accuracy and area under the receiver operating characteristic curve.

RESULTS

Of 178 episodes, 11.2% (N = 20) failed extubation. Using clinical/demographic data, our machine learning methods identified variables such as age, weight, height, and ventilation duration as being important in predicting extubation failure. Best classifier performance with this data was Boosting (prediction accuracy: 0.88; area under the receiver operating characteristic curve: 0.74). Using physiologic data, our machine learning methods found oxygen saturation extremes and descriptors of dynamic compliance, central venous pressure, and heart/respiratory rate to be of importance. The best classifier in this setting was Random Forest (prediction accuracy: 0.89; area under the receiver operating characteristic curve: 0.75). Combining both datasets produced classifiers highlighting the importance of physiologic variables in determining extubation failure, though predictive performance was not improved.

CONCLUSION

Physiologic variables not routinely scrutinised during extubation readiness trials were identified as potential extubation failure predictors. Larger analyses are necessary to investigate whether these markers can improve clinical decision-making.

Pediatric Ventilation Liberation: A Survey of International Practice Among 555 Pediatric Intensivists

Pediatric ventilation liberation has limited evidence, likely resulting in wide practice variation. To inform future work, practice patterns must first be described.

Effect of pediatric ventilation weaning technique on work of breathing

Background

Ventilator liberation is one of the most challenging aspects in patients with respiratory failure. Most patients are weaned through a transition from full to partial respiratory support, whereas some advocate using a continuous spontaneous ventilation (CSV). However, there is little scientific evidence supporting the practice of pediatric ventilator liberation, including the timing of onset of and the approach to weaning mode. We sought to explore differences in patient effort between a pressure controlled continuous mode of ventilation (PC-CMV) [in this cohort PC assist/control (PC-A/C)] with a reduced ventilator rate and CSV, and to study changes in patient effort with decreasing PS.

Methods

In this prospective physiology cross-over study, we randomized children < 5 years to first PC-A/C with a 25% reduction in ventilator rate, or CSV (continuous positive airway pressure [CPAP] + PS). Patients were then crossed over to the other arm. Patient effort was measured by calculating inspiratory work of breathing (WOB) using the Campbell diagram (WOB_Campbell), and by pressure–rate-product (PRP) and pressure–time-product (PTP). Respiratory inductance plethysmography (RIP) was used to calculate the phase angle. Measurements were obtained at baseline, during PC-A/C and CPAP + PS, and during decreasing set PS (maximum -6 cmH₂O).

Results

Thirty-six subjects with a median age of 4.4 (IQR 1.5–11.9) months and median ventilation time of 4.9 (IQR 3.4–7.0) days were included. Nearly all patients (94.4%) were admitted with primary respiratory failure. WOB_Campbell during baseline [0.67 (IQR 0.38–1.07) Joules/L] did not differ between CSV [0.49 (IQR 0.17–0.83) Joules/L] or PC-A/C [0.47 (IQR 0.17–1.15) Joules/L]. Neither PRP, PTP, ∆Pes nor phase angle was different between the two ventilator modes. Reducing pressure support resulted in a statistically significant increase in patient effort, albeit that these differences were clinically negligible.

Conclusions

Patient effort during pediatric ventilation liberation was not increased when patients were in a CSV mode of ventilation compared to a ventilator mode with a ventilator back-up rate. Reducing the level of PS did not lead to clinically relevant increases in patient effort. These data may aid in a better approach to pediatric ventilation liberation.

Trial registration clinicaltrials.gov NCT05254691. Registered 24 February 2022

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02106-6.

Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals: 2022 Update

The purpose of this document is to highlight practical recommendations to assist acute care hospitals to prioritize and implement strategies to prevent ventilator-associated pneumonia (VAP), ventilator-associated events (VAE), and non-ventilator hospital-acquired pneumonia (NV-HAP) in adults, children, and neonates. This document updates the Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals published in 2014. This expert guidance document is sponsored by the Society for Healthcare Epidemiology (SHEA), and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America, the American Hospital Association, the Association for Professionals in Infection Control and Epidemiology, and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

Associations With Extubation Failure and Predictive Value of Risk Analytics Algorithms With Extubation Readiness Tests Following Congenital Cardiac Surgery

OBJECTIVES

Extubation failure is associated with morbidity and mortality in children following cardiac surgery. Current extubation readiness tests (ERT) do not consider the nonrespiratory support provided by mechanical ventilation (MV) for children with congenital heart disease. We aimed to identify factors associated with extubation failure in children following cardiac surgery and assess the performance of two risk analytics algorithms for patients undergoing an ERT.

DESIGN

Retrospective cohort study.

SETTING

CICU at a tertiary-care children's hospital.

PATIENTS

Children receiving MV greater than 48 hours following cardiac surgery between January 1, 2017, and December 31, 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Six hundred fifty encounters were analyzed with 49 occurrences (8%) of reintubation. Extubation failure occurred most frequently within 6 hours of extubation. On multivariable analysis, younger age (per each 3-mo decrease: odds ratio [OR], 1.06; 95% CI, 1.001-1.12), male sex (OR, 2.02; 95% CI, 1.03-3.97), Society of Thoracic Surgery-European Association for Cardiothoracic Surgery category 5 procedure (p equals to 0.005), and preoperative respiratory support (OR, 2.08; 95% CI, 1.09-3.95) were independently associated with unplanned reintubation. Our institutional ERT had low sensitivity to identify patients at risk for reintubation (23.8%; 95% CI, 9.7-47.6%). The addition of the inadequate delivery of oxygen (IDO2) index to the ERT increased the sensitivity by 19.0% (95% CI, -2.5 to 40.7%; p = 0.05), but the sensitivity remained low and the accuracy of the test dropped by 8.9% (95% CI, 4.7-13.1%; p < 0.01).

CONCLUSIONS

Preoperative respiratory support, younger age, and more complex operations are associated with postoperative extubation failure. IDO2 and IVCO2 provide unique cardiorespiratory monitoring parameters during ERTs but require further investigation before being used in clinical evaluation for extubation failure.

Ventilation Weaning and Extubation Readiness in Children in Pediatric Intensive Care Unit: A Review

Ventilation is one of the most common procedures in critically ill children admitted to the pediatric intensive care units (PICUs) and is associated with potential severe side effects. The longer the mechanical ventilation, the higher the risk of infections, mortality, morbidity and length of stay. Protocol-based approaches to ventilation weaning could have potential benefit in assisting the physicians in the weaning process but, in pediatrics, clear significant outcome difference related to their use has yet to be shown. Extubation failure occurs in up to 20% of patients in PICU with evidences demonstrating its occurrence related to a worse patient outcome including higher mortality. Various clinical approaches have been described to decide the best timing for extubation which can usually be achieved by performing a spontaneous breathing trial before the extubation. No clear evidence is available over which technique best predicts extubation failure. Within this review we summarize the current strategies of ventilation weaning and extubation readiness evaluation employed in the pediatric setting in order to provide an updated view on the topic to guide intensive care physicians in daily clinical practice. We performed a thorough literature search of main online scientific databases to identify principal studies evaluating different strategies of ventilation weaning and extubation readiness including pediatric patients receiving mechanical ventilation. Various strategies are available in the literature both for ventilation weaning and extubation readiness assessment with unclear clear data supporting the superiority of any approach over the others.

Effect of Protocolized Weaning and Spontaneous Breathing Trial vs Conventional Weaning on Duration of Mechanical Ventilation: A Randomized Controlled Trial

Background

Identifying ventilated patients ready for extubation is a challenge for clinicians. Premature extubation increases risks of reintubation while delayed weaning increases complications of prolonged ventilation. We compared the duration of mechanical ventilation (MV) and extubation failure in children extubated using a weaning protocol based on pressure support spontaneous breathing trial (PS SBT) vs those extubated after nonprotocolized physician-directed weaning.

Patients and methods

A prospective randomized controlled trial was conducted in the pediatric intensive care unit of a tertiary care hospital in children ventilated for ≥24 hours. All eligible patients underwent daily screening and were randomized once found fit. The intervention group underwent PS SBT of 2 hours duration followed by a T-piece trial and extubation. Controls underwent conventional weaning with synchronized intermittent mandatory ventilation mode and a T-piece trial before extubation.

Results

Eighty patients were randomized into two groups of 40 each. About 77.5% of patients passed the PS SBT on the first attempt. No statistical difference was found either in the duration of MV between the two groups [median (interquartile range) in days: 4.77 (2.89, 9.46) in controls and 4.94 (2.23, 6.35) in cases, p = 0.62] or in the rate of extubation failure (13% and 10.5%, p = 1). Mortality was found to be significantly higher in the reintubated patients compared to those not reintubated in both groups (p = 0.002 in cases and 0.005 in controls).

Conclusion

Weaning using PS SBT-based protocol though did not shorten the duration of MV, it was found to be safe for assessing extubation readiness and did not increase extubation failure (CTRI no—CTRI/2018/04/013270).

How to cite this article

Kishore R, Jhamb U. Effect of Protocolized Weaning and Spontaneous Breathing Trial vs Conventional Weaning on Duration of Mechanical Ventilation: A Randomized Controlled Trial. Indian J Crit Care Med 2021;25(9):1059–1065.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Progression of Respiratory Support Following Pediatric Extubation

OBJECTIVES

High-flow nasal cannula and noninvasive positive pressure ventilation have become ubiquitous in contemporary PICUs. Practice patterns associated with the use of these modalities have not been well described. In this study, we aimed to describe the use of high-flow nasal cannula and noninvasive positive pressure ventilation in children after extubation and analyze the progression of usage in association with patient factors. Our secondary aim was to describe interventions used for postextubation stridor.

DESIGN

Single-center retrospective cohort study.

SETTING

A 36-bed quaternary medical-surgical PICU.

PATIENTS

Mechanically ventilated pediatric patients admitted between April 2017 and March 2018. Exclusions were patients in the cardiac ICU, patients requiring a tracheostomy or chronic ventilatory support, and patients with limited resuscitation status.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data regarding respiratory modality use was collected for the first 72 hours after extubation. There were 427 patients included in the analysis; 51 patients (11.9%) were extubated to room air, 221 (51.8%) to nasal cannula, 132 (30.9%) to high-flow nasal cannula, and 23 (5.4%) to noninvasive positive pressure ventilation. By 72 hours, 314 patients (73.5%) were on room air, 52 (12.2%) on nasal cannula, 29 (6.8%) on high-flow nasal cannula, eight (1.9%) on noninvasive positive pressure ventilation, and 24 (5.6%) were reintubated. High-flow nasal cannula was the most used respiratory modality for postextubation stridor. Multivariate analysis demonstrated that longer duration of invasive mechanical ventilation increased the odds of initial high-flow nasal cannula and noninvasive positive pressure ventilation use, and a diagnosis of cerebral palsy increased the odds of escalating from high-flow nasal cannula to noninvasive positive pressure ventilation in the first 24 hours post extubation.

CONCLUSIONS

High-flow nasal cannula is commonly used immediately after pediatric extubation and the development of postextubation stridor; however, its usage sharply declines over the following 72 hours. Larger multicenter trials are needed to identify high-risk patients for extubation failure that might benefit the most from prophylactic use of high-flow nasal cannula and noninvasive positive pressure ventilation after extubation.

High Breath-by-Breath Variability Is Associated With Extubation Failure in Children

OBJECTIVES

Extubation failure is multifactorial, and most tools to assess extubation readiness only evaluate snapshots of patient physiology. Understanding variability in respiratory variables may provide additional information to inform extubation readiness assessments.

DESIGN

Secondary analysis of prospectively collected physiologic data of children just prior to extubation during a spontaneous breathing trial. Physiologic data were cleaned to provide 40 consecutive breaths and calculate variability terms, coefficient of variation and autocorrelation, in commonly used respiratory variables (i.e., tidal volume, minute ventilation, and respiratory rate). Other clinical variables included diagnostic and demographic data, median values of respiratory variables during spontaneous breathing trials, and the change in airway pressure during an occlusion maneuver to measure respiratory muscle strength (maximal change in airway pressure generated during airway occlusion [PiMax]). Multivariable models evaluated independent associations with reintubation and prolonged use of noninvasive respiratory support after extubation.

SETTING

Acute care, children's hospital.

PATIENTS

Children were included from the pediatric and cardiothoracic ICUs who were greater than 37 weeks gestational age up to and including 18 years who were intubated greater than or equal to 12 hours with planned extubation. We excluded children who had a contraindication to an esophageal catheter or respiratory inductance plethysmography bands.

INTERVENTIONS

Noninterventional study.

MEASUREMENTS AND MAIN RESULTS

A total of 371 children were included, 32 of them were reintubated. Many variability terms were associated with reintubation, including coefficient of variation and autocorrelation of the respiratory rate. After controlling for confounding variables such as age and neurologic diagnosis, both coefficient of variation of respiratory rate(p < 0.001) and low PiMax (p = 0.002) retained an independent association with reintubation. Children with either low PiMax or high coefficient of variation of respiratory rate had a nearly three-fold higher risk of extubation failure, and when these children developed postextubation upper airway obstruction, reintubation rates were greater than 30%.

CONCLUSIONS

High respiratory variability during spontaneous breathing trials is independently associated with extubation failure in children, with very high rates of extubation failure when these children develop postextubation upper airway obstruction.

A Respiratory Therapist-Driven Pathway Improves Timeliness of Extubation Readiness Assessment in a Single PICU

OBJECTIVES

Our smart aim was to decrease the time between when a mechanically ventilated patient was eligible for and when they underwent their first extubation readiness test (delta time) by 50% within 3 months through the development and implementation of a respiratory therapist-driven extubation readiness test pathway.

DESIGN

Quality improvement project.

SETTING

Single, tertiary care, 24-bed, academic PICU.

PATIENTS

Pediatric patients admitted to the PICU and requiring mechanical ventilation for a primary pulmonary process.

INTERVENTIONS

We developed an extubation readiness test pathway that consisted of an eligibility screen and a standard testing process. Patients were screened every 3 hours. Upon passing the screen and being cleared by a prescriber, a test was initiated. No clinical management was dictated to prescribers.

MEASUREMENTS AND MAIN RESULTS

The preintervention and intervention cohorts included 109 and 43 mechanical ventilation courses, respectively. The mean delta time decreased from 33.77 hours to 2.92 hours after pathway implementation (p = 0.000). The medical length of stay decreased from 196.6 to 177.2 hours (p = 0.05). There were no statistically significant changes in duration of mechanical ventilation until first extubation (112.9 vs 122.3 hr; p = 0.651) and 48-hour extubation failure rate (16.5% vs 4.8%; p = 0.056). The sensitivity and positive predictive value for the extubation readiness test were 89.5% and 94.4%, respectively. The mean for all process compliance measures was 91.5%.

CONCLUSIONS

A respiratory therapist-driven extubation readiness test pathway can be safely implemented in a large, academic PICU. The pathway resulted in earlier extubation readiness testing without increasing key balancing measures-the duration of mechanical ventilation, PICU length of stay, or the extubation failure rate.

Spontaneous Breathing and Imposed Work During Pediatric Mechanical Ventilation: A Bench Study

OBJECTIVES

To calculate imposed work of breathing during simulated spontaneous breathing at a given tidal volume across the range of normal length or shortened pediatric endotracheal tube sizes and endotracheal tubes with an intraluminal catheter in situ.

DESIGN

In vitro study.

SETTING

Research laboratory.

INTERVENTIONS

A bench model (normal compliance, no airway resistance) simulating sinusoid flow spontaneous breathing used to calculate imposed work of breathing for various endotracheal tube sizes (3.0-7.5 mm). Imposed work of breathing was calculated by integrating inspiratory tidal volume over the end-expiratory difference between the positive end-expiratory pressure and the tracheal pressure. Measurements were taken at different combinations of set spontaneous tidal volume (2.5, 5.0, 7.5, and 10 mL/kg), age-appropriate inspiratory times, length of endotracheal tube, and presence of intraluminal catheter.

MEASUREMENTS AND MAIN RESULTS

Overall median imposed work of breathing (Joules/L) was not significantly different between the four age groups: 0.047 Joules/L (interquartile range, 0.020-0.074 Joules/L) for newborns, 0.077 Joules/L (interquartile range, 0.032-0.127 Joules/L) for infants, 0.109 Joules/L (interquartile range, 0.0399-0.193 Joules/L) for small children, and 0.077 Joules/L (interquartile range, 0.032-0.132 Joules/L) for adolescents. Shortening the endotracheal tubes resulted in a significant difference in reduction in overall imposed work of breathing, but the absolute reduction was most notable in small children (0.030 Joules/L) and the least effect in neonates (0.016 Joules/L). Overall imposed work of breathing increased in each age group when an intraluminal catheter was in situ: 91.09% increase in imposed work of breathing in neonates to 0.168 Joules/L, 84.98% in infants to 0.142 Joules/L, 81.98% in small children to 0.219 Joules/L, and 55.45% in adolescents to 0.140 Joules/L.

CONCLUSIONS

Calculated imposed work of breathing were not different across the range of endotracheal tube sizes. The low imposed work of breathing values found in this study might be appreciated as clinically irrelevant. Our findings add to the change in reasoning that it is appropriate to perform spontaneous breathing trials without pressure support. Nonetheless, our findings on the measured imposed work of breathing values need to be confirmed in a clinical study.

Spontaneous Breathing Trial for Prediction of Extubation Success in Pediatric Patients Following Congenital Heart Surgery: A Randomized Controlled Trial

OBJECTIVES

To evaluate the usefulness of a spontaneous breathing trial for predicting extubation success in pediatric patients in the postoperative period after cardiac surgery compared with a physician-led weaning.

STUDY DESIGN

Randomized, controlled trial.

SETTING

PICU of a tertiary-care university hospital.

PATIENTS

A population of pediatric patients following cardiac surgery for congenital heart disease.

INTERVENTIONS

Patients on mechanical ventilation for more than 12 hours after surgery who were considered ready for weaning were randomized to the spontaneous breathing trial group or the control group. The spontaneous breathing trial was performed on continuous positive airway pressure with the pressure support of 10 cmH2O, the positive end-expiratory pressure of 5 cmH2O, and the fraction of inspired oxygen less than or equal to 0.5 for 2 hours. Patients in the control group underwent ventilator weaning according to clinical judgment.

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was extubation success defined as no need for reintubation within 48 hours after extubation. Secondary outcomes were PICU length of stay, hospital length of stay, occurrence rate of ventilator-associated pneumonia, and mortality. One hundred and ten patients with the median age of 8 months were included in the study: 56 were assigned to the spontaneous breathing trial group and 54 were assigned to the control group. Demographic and clinical data and Risk Adjustment for Congenital Heart Surgery-1 classification were similar in both groups. Patients undergoing the spontaneous breathing trial had greater extubation success (83% vs 68%, p = 0.02) and shorter PICU length of stay (median 85 vs 367 hr, p < 0.0001) compared with the control group, respectively. There was no significant difference between groups in hospital length of stay, occurrence rate of ventilator-associated pneumonia, and mortality.

CONCLUSIONS

Pediatric patients with congenital heart disease undergoing the spontaneous breathing trial postoperatively had greater extubation success and shorter PICU length of stay compared with those weaned according to clinical judgment.

The effect of pressure support on imposed work of breathing during paediatric extubation readiness testing

BACKGROUND

Paediatric critical care practitioners often make use of pressure support (PS) to overcome the perceived imposed work of breathing (WOBimp) during an extubation readiness test (ERT). However, no paediatric data are available that shows the necessity of adding of pressure support during such tests. We sought to measure the WOBimp during an ERT with and without added pressure support and to study its clinical correlate. This was a prospective study in spontaneously breathing ventilated children < 18 years undergoing ERT. Using tracheal manometry, WOBimp was calculated by integrating the difference between positive end-expiratory pressure (PEEP) and tracheal pressure (Ptrach) over the measured expiratory tidal volume (VTe) under two paired conditions: continuous positive airway pressure (CPAP) with and without PS. Patients with post-extubation upper airway obstruction were excluded.

RESULTS

A total of 112 patients were studied. Median PS during the ERT was 10 cmH₂O. WOBimp was significantly higher without PS (median 0.27, IQR 0.20-0.50 J/L) than with added PS (median 0.00, IQR 0.00-0.11 J/L). Although there were statistically significant changes in spontaneous breath rate [32 (23-42) vs. 37 (27-46) breaths/min, p < 0.001] and higher ET-CO₂ [5.90 (5.38-6.65) vs. 6.23 (5.55-6.94) kPa, p < 0.001] and expiratory Vt decreased [7.72 (6.66-8.97) vs. 7.08 (5.82-8.08) mL/kg, p < 0.001] in the absence of PS, these changes appeared clinically irrelevant since the Comfort B score remained unaffected [12 (10-13) vs. 12 (10-13), P = 0.987]. Multivariable analysis showed that changes in WOBimp occurred independent of endotracheal tube size.

CONCLUSIONS

Withholding PS during ERT does not lead to clinically relevant increases in WOBimp, irrespective of endotracheal tube size.

Monitoring diaphragm function in a patient with myasthenia gravis: electrical activity of the diaphragm vs. maximal inspiratory pressure

Background

Maximal inspiratory pressure (MIP) is used to assess respiratory muscle strength of patients with myasthenia gravis (MG) requiring ventilatory support. Electrical activity of the diaphragm (E-di) has been used to guide weaning.

Case presentation

The MIP and tidal volume/ΔE-di (the patient-to-ventilator breath contribution) were monitored in a 12-year-old girl with MG requiring ventilator support. The same ventilatory settings were maintained until extubation. During weaning, MIP increased slightly, but varied unpredictably. Tidal volume/ΔE-di decreased at a constant rate as muscle strength recovered.

Conclusion

In this patient with muscle weakness, E-di was a reliable tool to monitor weaning from mechanical ventilation.

Risk Factors for Pediatric Extubation Failure: The Importance of Respiratory Muscle Strength

OBJECTIVE

Respiratory muscle weakness frequently develops during mechanical ventilation, although in children there are limited data about its prevalence and whether it is associated with extubation outcomes. We sought to identify risk factors for pediatric extubation failure, with specific attention to respiratory muscle strength.

DESIGN

Secondary analysis of prospectively collected data.

SETTING

Tertiary care PICU.

PATIENTS

Four hundred nine mechanically ventilated children.

INTERVENTIONS

Respiratory measurements using esophageal manometry and respiratory inductance plethysmography were made preextubation during airway occlusion and on continuous positive airway pressure of 5 and pressure support of 10 above positive end-expiratory pressure 5 cm H2O, as well as 5 and 60 minutes postextubation.

MEASUREMENTS AND MAIN RESULTS

Thirty-four patients (8.3%) were reintubated within 48 hours of extubation. Reintubation risk factors included lower maximum airway pressure during airway occlusion (aPiMax) preextubation, longer length of ventilation, postextubation upper airway obstruction, high respiratory effort postextubation (pressure rate product, pressure time product, tension time index), and high postextubation phase angle. Nearly 35% of children had diminished respiratory muscle strength (aPiMax ≤ 30 cm H2O) at the time of extubation, and were nearly three times more likely to be reintubated than those with preserved strength (aPiMax > 30 cm H2O; 14% vs 5.5%; p = 0.006). Reintubation rates exceeded 20% when children with low aPiMax had moderately elevated effort after extubation (pressure rate product > 500), whereas children with preserved aPiMax had reintubation rates greater than 20% only when postextubation effort was very high (pressure rate product > 1,000). When children developed postextubation upper airway obstruction, reintubation rates were 47.4% for those with low aPiMax compared to 15.4% for those with preserved aPiMax (p = 0.02). Multivariable risk factors for reintubation included acute neurologic disease, lower aPiMax, postextubation upper airway obstruction, higher preextubation positive end-expiratory pressure, higher postextubation pressure rate product, and lower height.

CONCLUSIONS

Neuromuscular weakness at the time of extubation was common in children and was independently associated with reintubation, particularly when postextubation effort was high.

Accuracy of an Extubation Readiness Test in Predicting Successful Extubation in Children With Acute Respiratory Failure From Lower Respiratory Tract Disease

OBJECTIVE

Identifying children ready for extubation is desirable to minimize morbidity and mortality associated with prolonged mechanical ventilation and extubation failure. We determined the accuracy of an extubation readiness test (Randomized Evaluation of Sedation Titration for Respiratory Failure extubation readiness test) in predicting successful extubation in children with acute respiratory failure from lower respiratory tract disease.

DESIGN

Secondary analysis of data from the Randomized Evaluation of Sedation Titration for Respiratory Failure clinical trial, a pediatric multicenter cluster randomized trial of sedation.

SETTING

Seventeen PICUs in the intervention arm.

PATIENTS

Children 2 weeks to 17 years receiving invasive mechanical ventilation for lower respiratory tract disease.

INTERVENTION

Extubation readiness test in which spontaneously breathing children with oxygenation index less than or equal to 6 were placed on FIO2 of 0.50, positive end-expiratory pressure of 5 cm H2O, and pressure support.

MEASUREMENTS AND MAIN RESULTS

Of 1,042 children, 444 (43%) passed their first extubation readiness test. Of these, 295 (66%) were extubated within 10 hours of starting the extubation readiness test, including 272 who were successfully extubated, for a positive predictive value of 92%. Among 861 children who were extubated for the first time within 10 hours of performing an extubation readiness test, 788 passed their extubation readiness test and 736 were successfully extubated for a positive predictive value of 93%. The median time of day for extubation with an extubation readiness test was 12:15 hours compared with 14:54 hours for extubation without an extubation readiness test within 10 hours (p < 0.001).

CONCLUSIONS

In children with acute respiratory failure from lower respiratory tract disease, an extubation readiness test, as described, should be considered at least daily if the oxygenation index is less than or equal to 6. If the child passes the extubation readiness test, there is a high likelihood of successful extubation.

Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals: 2014 Update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format to assist acute care hospitals in implementing and prioritizing strategies to prevent ventilator-associated pneumonia (VAP) and other ventilator-associated events (VAEs) and to improve outcomes for mechanically ventilated adults, children, and neonates. This document updates "Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals," published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Risk Factors for Extubation Failure Following Neonatal Cardiac Surgery

OBJECTIVE

Extubation failure after neonatal cardiac surgery has been associated with considerable postoperative morbidity, although data identifying risk factors for its occurrence are sparse. We aimed to determine risk factors for extubation failure in our neonatal cardiac surgical population.

DESIGN

Retrospective chart review.

SETTING

Urban tertiary care free-standing children's hospital.

PATIENTS

Neonates (0-30 d) who underwent cardiac surgery at our institution between January 2009 and December 2012 was performed.

INTERVENTIONS

Extubation failure was defined as reintubation within 72 hours after extubation from mechanical ventilation. Multivariate logistic regression analysis was performed to determine independent risk factors for extubation failure.

MEASUREMENTS AND MAIN RESULTS

We included 120 neonates, of whom 21 (17.5%) experienced extubation failure. On univariate analysis, patients who failed extubation were more likely to have genetic abnormalities (24% vs 6%; p = 0.023), hypoplastic left heart (43% vs 17%; p = 0.009), delayed sternal closure (38% vs 12%; p = 0.004), postoperative infection prior to extubation (38% vs 11%; p = 0.002), and longer duration of mechanical ventilation (median, 142 vs 58 hr; p = 0.009]. On multivariate analysis, genetic abnormalities, hypoplastic left heart, and postoperative infection remained independently associated with extubation failure. Furthermore, patients with infection who failed extubation tended to receive fewer days of antibiotics prior to their first extubation attempt when compared with patients with infection who did not fail extubation (4.9 ± 2.6 vs 7.3 ± 3; p = 0.073).

CONCLUSIONS

Neonates with underlying genetic abnormalities, hypoplastic left heart, or postoperative infection were at increased risk for extubation failure. A more conservative approach in these patients, including longer pre-extubation duration of antibiotic therapy for postoperative infections, may be warranted.

Clinical Epidemiology of Extubation Failure in the Pediatric Cardiac ICU: A Report From the Pediatric Cardiac Critical Care Consortium

OBJECTIVE

To describe the clinical epidemiology of extubation failure in a multicenter cohort of patients treated in pediatric cardiac ICUs.

DESIGN

Retrospective cohort study using prospectively collected clinical registry data.

SETTING

Pediatric Cardiac Critical Care Consortium registry.

PATIENTS

All patients admitted to the CICU at Pediatric Cardiac Critical Care Consortium hospitals.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Analysis of all mechanical ventilation episodes in the registry from October 1, 2013, to July 31, 2014. The primary outcome of extubation failure was reintubation less than 48 hours after planned extubation. Repeated-measures analysis using generalized estimating equations to account for within patient and center correlation was performed to identify risk factors for extubation failure. Adjusted extubation failure rates for each hospital were calculated using logistic regression controlling for patient factors. Of 1,734 mechanical ventilation episodes (1,478 patients at eight hospitals) ending in a planned extubation, there were 100 extubation failures (5.8%). In multivariable analysis, only longer duration of mechanical ventilation was significantly associated with extubation failure (p = 0.01); the failure rate was 4% when ventilated less than 24 hours, 9% after 24 hours, and 13% after 7 days. For 503 patients intubated and extubated in the cardiac operating room, 15 patients (3%) failed extubation within 48 hours (12 within 24 hr). Case-mix-adjusted extubation failure rates ranged from 1.1% to 9.8% across hospitals. Patients failing extubation had greater median cardiac ICU length of stay (15 vs 3 d; p < 0.001) and in-hospital mortality (7.9 vs 1.2%; p < 0.001).

CONCLUSIONS

Though extubation failure is uncommon overall, there may be opportunities to improve extubation readiness assessment in patients ventilated more than 24 hours. These data suggest that extubation in the operating room after cardiac surgery can be done with a low failure rate. We observed variation in extubation failure rates across hospitals, and future investigation must elucidate the optimal strategies of high-performing centers to reduce ventilation time while limiting extubation failures.

Strategies to prevent ventilator-associated pneumonia in acute care hospitals: 2014 update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format to assist acute care hospitals in implementing and prioritizing strategies to prevent ventilator-associated pneumonia (VAP) and other ventilator-associated events (VAEs) and to improve outcomes for mechanically ventilated adults, children, and neonates. This document updates “Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals,” published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Preventing extubation failures in a pediatric intensive care unit

The objective of this project was to reduce the number of failed extubations in the pediatric intensive care unit. This article describes extubation failures in the pediatric intensive care unit and the development and implementation of an extubation readiness protocol using the Iowa Model for Evidence-based Practice as a guideline. The Iowa Model consists of processes for implementing evidence into practice, such as critiquing and synthesizing the literature, identifying stakeholders, and recognizing triggers. The extubation protocol was developed excluding children with previous lung injury and/or neuromuscular conditions, which contribute to an increased risk and complexity of planned extubations.

Weaning from mechanical ventilation in paediatrics. State of the art

Weaning from mechanical ventilation is one of the greatest volume and strength issues in evidence-based medicine in critically ill adults. In these patients, weaning protocols and daily interruption of sedation have been implemented, reducing the duration of mechanical ventilation and associated morbidity. In paediatrics, the information reported is less consistent, so that as yet there are no reliable criteria for weaning and extubation in this patient group. Several indices have been developed to predict the outcome of weaning. However, these have failed to replace clinical judgement, although some additional measurements could facilitate this decision.