Neurally Adjusted Ventilatory Assist (NAVA) Use in Infants With Acute Viral Bronchiolitis: a Randomised, Crossover Feasibility Study
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 16
- 试验地点
- 2
- 主要终点
- Changes to neuroventilatory efficiency when ventilation parameters are titrated
研究概览
简要总结
This exploratory intervention feasibility study aims to evaluate the use of a novel mode of ventilation known as Neurally adjusted ventilatory assist (NAVA) in infants with acute viral bronchiolitis.
The main aims are:
-
To determine whether an optimal combination of NAVA support level and Positive End Expiratory Pressure (PEEP) exists that can:
-
maximise aspects of respiratory muscle unloading and
-
minimize air trapping
-
To evaluate the impact of two morphine infusion doses on comfort levels and respiratory drive (standard = 20mcg/kg/hr, low = 5mcg/kg/hr) during ventilation titration.
Patients will act as their own control and will be randomly allocated to receive either standard or low dose morphine. They will receive the alternate dose on day 2. During each period of morphine dosing ventilation levels will be titrated and vital signs, respiratory parameters and comfort b scales will be recorded.
详细描述
This study is a Randomised, non-blinded, crossover (morphine dose), mode of ventilation feasibility study to evaluate the use of NAVA in infants with acute viral bronchiolitis.
Background and study aims:
This study aims to evaluate a novel mode of mechanical ventilation (breathing machine), Neurally Adjusted Ventilatory Assist (NAVA), in infants admitted to the paediatric intensive care unit (PICU) with acute viral bronchiolitis. This respiratory illness accounts for 12% of PICU admissions nationally. Current modes of ventilation are inefficient, often requiring prolonged use of sedative drugs for comfort and to improve ease of ventilation (synchronicity). Consequences of prolonged sedative use are muscle wastage including the respiratory muscles, increased risk of developing secondary infections and the potential for withdrawal from medication symptoms.
NAVA is a mode of ventilation that is delivered using our current ventilators (breathing machines). However, it differs from current modes by providing respiratory support in proportion to the signal from the brain to move the diaphragm, this is achieved via measurement of electrical activity of the diaphragm (the main muscle used to initiate a breath). This is measured by using a modified version of the patients' feeding tube (which is used in PICU to feed patients whilst on a ventilator).
Research in children to date has demonstrated that NAVA, compared to other ventilatory modes, allows for improved ventilator synchrony, reduced work of breathing and potentially less sedative use. This is consistent with our clinical impression (we have been using NAVA in an ad hoc way for >5 years). Although some of these studies included infants with bronchiolitis, the findings were not specific to this patient group. Of note, we do not yet know how to optimise NAVA settings in bronchiolitis, and whether current common sedative drugs (e.g. morphine) affect this, by decreasing respiratory drive excessively (potentially compromising NAVA utility).
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Other
- 盲法
- None
入排标准
- 年龄范围
- 1 Day 至 1 Year（Child）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Infants aged > 36 weeks corrected gestation and < 1 year of age
- •Admitted to PICU with acute viral bronchiolitis within 48 hours of admission
- •Likely to require mechanical ventilation for > 24 hours after enrolment
- •Able to pass a nasogastric tube
排除标准
- •Apnoea as a primary reason for ventilation in the absence of respiratory symptoms
- •History of gastro-intestinal bleeds in previous 30 days or significant coagulopathy
- •Facial trauma or surgery
- •Known neuro-muscular disease or diaphragmatic palsy
- •Haemodynamic instability (requiring inotropes)
结局指标
主要结局
Changes to neuroventilatory efficiency when ventilation parameters are titrated
时间窗: Measures will be recorded during the intervention
Measured by a change in neuro-ventilatory efficiency (NVE) during titration of ventilation settings NVE is measured as a ratio between electrical activity of the diaphragm (Edi) and patient's tidal volume during inspiration (Edi/Tv). An improvement in NVE can be demonstrated by a decrease in Edi without a fall in Tv.
Changes to neuromuscular efficiency when ventilation parameters are titrated.
时间窗: Measures will be recorded during the intervention
Measured by a change neuro-muscular efficiency (NME) during changes in ventilation settings NME measures Edi against the generated airway pressure during an occlusion (P0.1) thus providing an estimate of inspiratory driving pressure normalized to inspiratory neural inspiratory effort. This will be presented as a ratio: Paw (airway pressure) - PEEP)/ Edi.
Change in Electrical activity of the diaphragm (Edi) when ventilator parameters are titrated
时间窗: Measures will be recorded immediately after each intervention
Edi is a reflection of the electrical activity on the diaphragm. Normal Edi is 5-15 microvolts. There would be an expectation that this would change if the ventilation is meeting the patients ventilatory demands
changes in respiratory rate
时间窗: Measures will be recorded immediately after each intervention
Changes in respiratory rate will be recorded to ensure they are within normal range for the child's age.
Stabilisation of vital signs
时间窗: Measures will be recorded immediately after each intervention
Changes in transcutaneous carbon dioxide (TCO2) will be recorded to ensure they are within normal range for the child's age.
Changes to air trapping when ventilation parameters are titrated
时间窗: Measures will be recorded immediately after each intervention
A forced deflation (FD) will require pressure to be applied to the thoracic area to mimic a forced exhalation - pressure loops will be recorded via the servo-i during this time. This will give an idea of forced vital capacity and the amount of airway resistance as FD causes dynamic compression of the airways. Residual volume will indicate level of air-trapping occurring. Forced Expiratory Volume (FEV) will be measured at the end of each PEEP level to assess the residual volume, a marker of air-trapping to assess whether PEEP titration overcomes intrinsic PEEP. This will be measured using a standardised physiotherapy technique. A large inflation breath (approx. 40cmH20) will be administered to the patient and held for 3 seconds followed by a manual compression, the ventilator will record flow loops from this compression - the degree of scalloping will be quantified in measuring the degree of air trapping using a validated calculation.
Maintenance of patient comfort
时间窗: Measures will be recorded immediately after each intervention
Patient comfort will be measured using a COMFORT-Behavioral Scale (COMFORT-b). The COMFORT-b scale is an observational scale that has been validated for assessing comfort in children in PICU. Pain in children from 0-3 years of age and sedation in the 0-16 year old child. A score of 0-40 with a score greater than 22 indicating discomfort.
Changes in blood pressure
时间窗: Measures will be recorded immediately after each intervention
Changes to blood pressure will be recorded to ensure they are within normal range for the child's age.
Changes in heart rate
时间窗: Measures will be recorded immediately after each intervention
Changes to heart rate heart Rate recorded to ensure they are within normal range for the child's age.
次要结局
- To record the incidence of adverse events(On study completion up to 1 year)
- To assess recruitment rate(On study completion up to 1 year)
- To assess retention rates(On study completion up to 1 year)
- To assess time to recruit participants(On study completion up to 1 year)
- To assess the willingness of clinicians to recruit participants(On study completion up to 1 year)