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Abstract
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.
- Neonatology
- Respiratory
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What is already known on this topic?
Mechanical ventilation (MV) is still a common therapy in extremely preterm infants despite the increased use of non-invasive respiratory support.
Weaning, assessment of extubation readiness and provision of postextubation respiratory support are complex steps necessary for timely and successful extubation.
Determination of worldwide periextubation practices can help identify unnecessary variations in practice and delineate need for better evidence to inform guidelines.
What this study adds?
In the new era where MV is increasingly reserved for the sickest preterm infants failing initial non-invasive support, periextubation practices vary considerably.
Decisions are frequently physician dependent; not always evidence based. A small proportion of units use spontaneous breathing trials, but duration and perceived usefulness are quite variable.
Extubation failure definition is highly variable and well-defined criteria for reintubation are rarely used. Higher levels of evidence are necessary to standardise care.
Introduction
Mechanical ventilation (MV) is commonly used to support extremely preterm infants (<28 weeks gestation) but has important associated complications.1 Therefore, clinicians prefer to use non-invasive ventilation initially to avoid MV, but when intubation is required, they try to remove the endotracheal tube as soon as possible. However, the process leading towards extubation is complex, requires careful planning and involves three major steps: weaning, assessment of extubation readiness and provision of postextubation support.2 Furthermore, definitions of extubation failure (EF) and the criteria for reintubation are inconsistent and rates of EF appear to be high.3 Unfortunately, there is little high-quality evidence to guide clinicians during this periextubation period, leading to wide variations in practice,4 which can affect important outcomes.5
Protocols are widely used to reduce unnecessary variations in practice and improve outcomes.6 ,7 Therefore, the development and implementation of protocols for the three major steps involved in the periextubation period have been recommended by the American College of Chest Physician and the American College of Critical Care Medicine in adults.8 In paediatric and neonatal patients, the evidence is much less compelling.9 ,10 However, improvements in outcomes have been reported by some centres, including faster weaning from MV with the use of a respiratory therapist-driven protocol,11 earlier extubation with the routine performance of a spontaneous breathing trial (SBT) to assess extubation readiness12 and lower bronchopulmonary dysplasia (BPD) rates with application of strict guidelines for nasal continuous positive airway pressure (CPAP) therapy.13
Therefore, we designed a survey to identify periextubation practices across five countries in three different continents. We also aimed to examine the criteria used to define EF and the need for reintubation.
Methods
A survey consisting of 13 questions related to periextubation practices involving some aspects of weaning from MV, assessment of extubation readiness and postextubation respiratory support was developed after review of the literature and consultation with experts in neonatal respiratory care (see online supplementary appendix A). All questions focused on the respiratory care of extremely preterm infants, that is, those less than 28 weeks gestation. The questionnaire was distributed electronically between October 2013 and February 2014, with bimonthly reminders. All level III NICU clinical directors were identified using the official medical directory for each country (Canada, USA, Ireland, Australia and New Zealand). Consent was inferred by completing the survey.
We asked about the use of guidelines or protocols for ventilator weaning and the professional group responsible for making the decisions about weaning. We also ascertained the earliest age when the first extubation attempt would be considered, as well as criteria used to assess extubation readiness. More specifically, we inquired about the use of a SBT, a challenge whereby the infant is breathing spontaneously through the endotracheal tube for fixed time duration while clinical status is assessed. After providing a broad definition of SBT, we asked respondents whether they used the SBT in their unit, and if so the duration of the trial and criteria used to determine its success or failure. Furthermore, we asked about the types of respiratory support used immediately following extubation.
We also assessed whether units had specific criteria to guide reintubation. We asked respondents to define EF, the rate of EF in their unit and whether they considered EF to be an independent risk factor for mortality and morbidity in these infants.
Results
The questionnaire was sent electronically to 158 NICU’s, out of which 112 (71%) responded: 62/93 (67%) from USA, 21/30 (70%) from Canada, 14/21 (67%) from Australia, 5/6 (83%) from New Zealand and 8/8 (100%) from Ireland. Two responders skipped the question about their country.
Periextubation practices
Weaning from MV
Thirty-six per cent of the NICUs reported having a guideline (31%) or written protocol (5%) for ventilator weaning. Decisions about weaning were made by the one or more of the following: staff neonatologist (99%), neonatal fellow (71%) or nurse practitioner (54%).
Assessment of extubation readiness
Extubation readiness was assessed based on multiple criteria, including ventilatory settings (98%), blood gases (92%) and the presence of clinical and haemodynamic stability (86%). Fifty-four per cent of respondents ensured that infants received caffeine within 24 h prior to extubation. Only 16% of units routinely extubated infants on the premise that they passed a SBT, but up to 38% at least sometimes used it as part of their assessment. The SBT was of variable duration ranging from 3 min (25%) to more than 10 min (35%). Most of the centres were either neutral (55%) or disagreed (23%) with the idea that a SBT could help to predict extubation readiness. Following weaning and assessment of extubation readiness, the first attempt to extubate was performed anytime from immediately after surfactant administration (18%) up to more than 14 days of life (1%), although the majority of centres extubated between 1 and 3 days of life (figure 1).
Age at first extubation attempt.
Postextubation respiratory support
Nasal CPAP was the most common type of postextubation respiratory support used (84%) followed by nasal intermittent positive pressure ventilation (NIPPV) (55%) and high-flow nasal cannula (HFNC) (33%). A minority of centres (10%) reported using low-flow nasal cannula, oxyhood or no support during the immediate postextubation phase.
Definition and criteria of EF
The decision to reintubate was mainly based on clinical judgement of the responsible physician (88%); only 12% of units had well-defined criteria to guide reintubation. There was a lack of consensus on the time frame for definition of EF, with the majority proposing a period between 24 and 72 h (figure 2). Most respondents (79%) estimated having an EF rate between 10% and 30% in their unit. At the same time, 43% believed that EF was an independent risk factor for increased mortality and morbidity.
Time frame used to define extubation failure.
Discussion
Using a simple and pragmatic survey, we were able to obtain very important information about periextubation practices from a large number of units across five countries located in three continents. The descriptive analysis revealed significant variations in practices, with a lack of specific guidelines or protocols to streamline management. It also identified some approaches that were inconsistent with current evidence. Our results are concerning because this survey has been conducted in an era where intubation and MV are increasingly reserved for the sickest preterm infants who fail a trial of non-invasive support and are therefore under higher risk of EF, with a potentially inherent increase in morbidity and mortality.
Practice variability most commonly stemmed from a lack of, or conflicting evidence to support one respiratory approach over another. For instance, weaning from MV continues to be performed in a non-standardised manner, mostly by the staff neonatologist or neonatal fellow on service. This physician-dependent model contrasts with adult and paediatric acute care practices, whereby the use of healthcare professional-driven protocols for ventilation weaning has become standard of care.14–16 The evidence to support MV protocols in the preterm population, although promising, is still scarce.4 ,11 Similarly, the decision to extubate is also subjective and non-evidence based, primarily relying on ventilator settings, blood gases and the presence of clinical stability.3
In the absence of accurate and objective predictors of extubation readiness, we found a growing interest in using a SBT as part of the assessment process. This strategy has been recently reinvestigated in three small, single-centre studies.12 ,17 ,18 However, in clinical practice we noted the use of variable duration of the SBTs ranging from less than 3 to more than 10 min. Such findings highlight the need for more evidence to evaluate the routine use of SBTs as a regular assessment tool, particularly with regard to the duration, criteria for success or failure and accuracy.
In relation to postextubation respiratory support, extremely preterm infants were most frequently extubated to CPAP, followed by NIPPV and HFNC. All three therapies have been demonstrated in large randomised control trials (RCTs) to be effective in reducing the risk of EF.19–21 The significantly higher CPAP usage could be explained by its familiarity, cost, ease of use and the extensive body of literature in the past decade. NIPPV, on the other hand, was not as consistently adopted by units. We observed very similar rates of NIPPV use when compared with two other surveys in Ireland22 and England.23 This could be explained by the fact that several questions related to ventilator settings (pressures and rates) and use of synchronisation during NIPPV remain unanswered.24 ,25 Although a meta-analysis of several small, single-centre studies concluded that NIPPV was superior to CPAP after extubation,26 the large pragmatic multinational RCT failed to demonstrate any reduction in BPD, mortality or the combined outcome.20
In some instances, we observed that outcomes of clinical research were not always readily translated into clinical practice, even when evidence of effectiveness already existed. Indeed, 10% of centres still reported extubating extremely preterm infants to low-flow nasal cannula, oxyhood or no support, despite the evidence favouring the use of CPAP, NIPPV or HFNC. Similarly, only 54% of respondents took into account the administration of caffeine prior to extubation, despite substantial evidence in favour of its use.27
Evidence is lacking to support any criteria or specific time frame to define EF in extremely preterm infants, which was apparent in our survey. Indeed, the large majority of the respondents used a time frame of ≤72 h to define EF (93%), which mainly reflects what studies have traditionally used. This short time frame has recently been challenged.3 When looking at infants below 1000 g, reintubation rate rises in proportion to the observation period, even when the definition extends to 7 days. In other words, using EF definitions of 72 h or less may underestimate the true failure rate and therefore give centres false reassurance about their clinical practice and outcomes. Finally, nearly half the respondents believed that EF was an independent risk factor for increased mortality and morbidity despite the lack of strong evidence in the neonatal population. We speculate that this belief may come from the strong evidence from the adult28 ,29 and paediatric literature 30 ,31 and the multiple mechanisms involved in the process of endotracheal reintubation, reopening of atelectatic lungs (biotrauma) and reinitiation of MV, all potentially harmful to the preterm lungs. Therefore, a consensus regarding the definition of EF is needed to determine acceptable reintubation rates and to understand the risks associated with reintubation in the extremely preterm population.
Our study had some important limitations. Responses were provided by a single individual and may not have been representative of the collective unit practice. The responses may also have reflected what people say they do, but not necessarily what they actually do in clinical practice. We deemed that the clinical medical directors of each unit would be best suited to represent their unit. Our survey was simple and pragmatic. This helped us achieve a good response rate but meant that more details were not sought.
Conclusions
Our survey demonstrated that periextubation practices in extremely preterm infants vary considerably. Decisions are frequently physician dependent and not always evidence based. A small proportion of units use SBTs, but the duration and perceived usefulness of the test vary considerably. The definition of EF is highly variable and well-defined criteria for reintubation are rarely used. Thus, the results of this survey should be used to further stimulate research that can provide evidence to inform guidelines and standardise periextubation practices in modern neonatology.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
- Data supplement 1 - Online supplement
Footnotes
Contributors WS: conceptualised and designed study, performed data analysis, drafted the initial manuscript and approved the final manuscript as submitted. HA, GD, MK and PGD: participated in the development of the survey and design of the study, reviewed and revised the manuscript and approved the final manuscript as submitted. GS: conceptualised and designed study, participated in the data analysis, reviewed and revised the manuscript and approved the final manuscript as submitted.
Funding WS was supported by the Richard and Edith Strauss Fellowship Award from McGill University and GS from a Canadian Institute of Health Research Grant. ED is supported by Science Foundation Ireland Grant No. INFANT-12/RC/2272.
Competing interests None declared.
Ethics approval McGill University Health Centre, Canada—Research Ethics Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Authors agree with data sharing of their original research article.