Wissam Shalish

International survey on periextubation practices in extremely preterm infants

Objective To determine periextubation practices in extremely preterm infants (<28 weeks gestation). Design A survey consisting of 13 questions related to weaning from mechanical ventilation, assessment of extubation readiness and postextubation respiratory support was developed and sent to clinical directors of level III NICUs in Australia, Canada, Ireland, New Zealand and USA. A descriptive analysis of the results was performed. Results 112/162 (69%) units responded; 36% reported having a guideline (31%) or written protocol (5%) for ventilator weaning. Extubation readiness was assessed based on ventilatory settings (98%), blood gases (92%) and the presence of clinical stability (86%). Only 54% ensured that infants received caffeine ≤24 h prior to extubation. 16% of units systematically extubated infants on the premise that they passed a Spontaneous Breathing Test with a duration ranging from 3 min (25%) to more than 10 min (35%). Nasal continuous positive airway pressure was the most common type of respiratory support used (84%) followed by nasal intermittent positive pressure ventilation (55%) and high-flow nasal cannula (33%). Reintubation was mainly based on clinical judgement of the responsible physician (88%). There was a lack of consensus on the time frame for definition of extubation failure (EF), the majority proposing a period between 24 and 72 h; 43% believed that EF is an independent risk factor for increased mortality and morbidity. Conclusions Periextubation practices vary considerably; decisions are frequently physician dependent and not evidence based. The definition of EF is variable and well-defined criteria for reintubation are rarely used. High-quality trials are required to inform guidelines and standardise periextubation practices.

Feature selection and oversampling in analysis of clinical data for extubation readiness in extreme preterm infants

We present an approach for the analysis of clinical data from extremely preterm infants, in order to determine if they are ready to be removed from invasive endotracheal mechanical ventilation. The data includes over 100 clinical features, and the subject population is naturally quite small. To address this problem, we use feature selection, specifically mutual information, in order to choose a small subset of informative features. The other challenge we address is class imbalance, as there are many more babies that succeed extubation than those who fail. To handle this problem, we use SMOTE, an algorithm which creates synthetic examples of the minority class.

Organizational principles of cloud storage to support collaborative biomedical research

This paper describes organizational guidelines and an anonymization protocol for the management of sensitive information in interdisciplinary, multi-institutional studies with multiple collaborators. This protocol is flexible, automated, and suitable for use in cloud-based projects as well as for publication of supplementary information in journal papers. A sample implementation of the anonymization protocol is illustrated for an ongoing study dealing with Automated Prediction of EXtubation readiness (APEX).

Predictors of extubation readiness in preterm infants: a systematic review and meta-analysis

Context A variety of extubation readiness tests have already been incorporated into clinical practice in preterm infants. Objective To identify predictor tests of successful extubation and determine their accuracy compared with clinical judgement alone. Methods MEDLINE, Embase, PubMed, Cochrane Library and Web of Science were searched between 1984 and June 2016. Studies evaluating predictors of extubation success during a period free of mechanical inflations in infants less than 37 weeks’ gestation were included. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. After identifying and describing all predictor tests, pooled sensitivity and specificity estimates for the different test categories were generated using a bivariate random-effects model. Results Thirty-five studies were included, showing wide heterogeneities in population characteristics, methodologies and definitions of extubation success. Assessments ranged from a few seconds to 24 hours, provided 0–6 cmH2O positive end-expiratory pressure and measured several clinical and/or physiological parameters. Thirty-one predictor tests were identified, showing good sensitivities but low and variable specificities. Given the high variation in test definitions across studies, pooling could only be performed on a subset. The commonly performed spontaneous breathing trials had pooled sensitivity of 95% (95% CI 87% to 99%) and specificity of 62% (95% CI 38% to 82%), while composite tests offered the best performance characteristics. Conclusions There is a lack of strong evidence to support the use of extubation readiness tests in preterm infants. Although spontaneous breathing trials are attractive assessment tools, higher quality studies are needed for determining the optimal strategies for improving their accuracy.

Uses and misuses of albumin during resuscitation and in the neonatal intensive care unit

Albumin is one of the most abundant proteins in plasma and serves many vital functions. Neonatal concentrations vary greatly with gestational and postnatal age. In critically ill neonates, hypoalbuminemia occurs due to decreased synthesis, increased losses or redistribution of albumin into the extravascular space, and has been associated with increased morbidities and mortality. For that reason, infusion of exogenous albumin as a volume expander has been proposed for various clinical settings including hypotension, delivery room resuscitation, sepsis and postoperative fluid management. Albumin is often prescribed in infants with hypoalbuminemia, hyperbilirubinemia, and protein-losing conditions. However, the evidence of these practices has not been reviewed or validated. Albumin infusion may initiate highly complex processes that vary according to the individual and disease pathophysiology. Indeed, it may be associated with harms when misused. In this review, we critically appraise the scientific evidence for administering albumin in most conditions encountered in the neonatal intensive care unit, while emphasizing the benefits and risks associated with their use.

Automated ongoing data validation and quality control of multi-institutional studies

This paper addresses the problem of ensuring the validity and quality of data in ongoing multi-disciplinary studies where data acquisition spans several geographical sites. It describes an automated validation and quality control procedure that requires no user supervision and monitors data acquired from different locations before analysis. The procedure is illustrated for the Automated Prediction of Extubation readiness (APEX) project in preterm infants, where acquisition of clinical and cardiorespiratory data occurs at 6 sites using different equipment and personnel. We have identified more than 40 problems with clinical information and 25 possible problems with the cardiorespiratory signals. Our validation and quality control procedure identifies these problems in an ongoing manner so that they can be timely addressed and corrected throughout this long-term collaborative study.

Heart Rate Variability in Extremely Preterm Infants Receiving Nasal CPAP and Non-Synchronized Noninvasive Ventilation Immediately After Extubation

INTRODUCTION: There is a paucity of studies comparing the physiological effects of nasal CPAP or non-synchronized noninvasive ventilation (ns-NIV) during the postextubation phase in preterm infants. Heart rate variability (HRV) can identify system instability before clinical or laboratory signs of deterioration. Thus, we sought to investigate any differences in HRV between those modes. METHODS: 15 preterm infants with birthweight ≤1,250 g and undergoing their first extubation attempt were studied immediately after disconnection from mechanical ventilation. Electrocardiogram (ECG) recordings were obtained while on nasal CPAP and ns-NIV in a random order (30–60 min on each). Time and frequency domain analyses were used to calculate HRV from 5-min segments of ECG. RESULTS: 12 of 15 infants were analyzed (3 were excluded for low ECG quality): 7 successes and 5 failures. HRV parameters were higher during ns-NIV when compared to nasal CPAP, but differences were not statistically different. However, absolute and relative differences in HRV values (all time domain parameters) were significantly higher in infants who failed extubation during ns-NIV. CONCLUSIONS: Nasal CPAP or ns-NIV provided immediately postextubation did not affect HRV. Interestingly, in an exploratory analysis, changes in HRV did occur during ns-NIV in the subgroup of infants who failed extubation. Hence, changes in HRV as early as 2 h after extubation should be further explored in larger studies as a potential predictor of postextubation respiratory failure.

Correlation of clinical parameters with cardiorespiratory behavior in successfully extubated extremely preterm infants

Extremely preterm infants (gestational age ≤ 28 weeks) often require EndoTracheal Tube-Invasive Mechanical Ventilation (ETT-IMV) to survive. Clinicians wean infants off ETT-IMV as early as possible using their judgment and clinical information. However, assessment of extubation readiness is not accurate since 20 to 40% of preterm infants fail extubation. We extended our work in automated prediction of extubation readiness by examining correlations of automated cardiorespiratory features to clinical parameters in successfully extubated infants. Only a few features, mainly those related to variability of breathing synchrony, had any consistent correlation with clinical parameters, namely gestational age, day of life at extubation, and bicarbonate. We conclude that the automated cardiorespiratory features likely provide different information additional to clinical practice.