The objective of this study is to evaluate the effects of continuous positive airway pressure and nasal intermittent positive pressure ventilation on breathing pattern variables of very low birth weight neonates immediately after extubation.
The effects of non-invasive ventilation on the respiratory function of neonates have not been fully elucidated. Currently, two modalities of non invasive ventilation are commonly used in Brazilian neonatal intensive care units: continuous positive airway pressure (CPAP) and nasal intermittent positive pressure ventilation (NIPPV). In this study, it was hypothesized that NIPPV will improve tidal volume when compared to CPAP. The objective of this study is to evaluate the effects of continuous positive airway pressure and nasal intermittent positive pressure ventilation on breathing pattern variables of very low birth weight neonates immediately after extubation. Soon after extubation, the neonates will be randomized into the CPAP-NIPPV (sequence 1) or the NIPPV-CPAP (sequence 2). The sequence will be assigned at random using sealed envelopes. Respiratory inductive plethysmography will be used to evaluate the breathing pattern (tidal volume, respiratory rate, minute ventilation, mean inspiratory flow) and chest wall motion (labor breathing index, inspiratory phase relation, expiratory phase relation, total phase relation and phase angle). Student t tests for paired samples will be used and the Wilcoxon test according to the data distribution. A significance level of 5% will be adopted. The analyzes will be performed by StatisticalPackage software for the Social Sciences® (SPSS, Chicago, IL, USA), version 17.0 for Windows.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
17
\- NIPPV The following parameters: inspiratory pressure = 15 cmH2O / final expiratory positive pressure = 6 cmH2O / inspiratory time = 0.40 / flow = 6-8 L.min-1 / respiratory rate = 24. Respiratory inductive plethysmography is used to evaluate breathing pattern (tidal volume, respiratory rate, minute ventilation, mean inspiratory flow) and chest wall motion (labor breathing index - LBI, phase relation in inspiratory breathing - PhRIB, phase relation in expiratory breathing - PhREB, total phase relation - PhRTB and phase angle).
\- CPAP The following parameters: pressure of 6 cmH2O, with flow of 6-8L/min. Respiratory inductive plethysmography is used to evaluate breathing pattern (tidal volume, respiratory rate, minute ventilation, mean inspiratory flow) and chest wall motion (labor breathing index - LBI, phase relation in inspiratory breathing - PhRIB, phase relation in expiratory breathing - PhREB, total phase relation - PhRTB and phase angle).
Hospital das Clínicas da UFMG
Belo Horizonte, Minas Gerais, Brazil
Laboratório de Avaliação e Pesquisa em Desempenho Cardiorrespiratório da UFMG
Belo Horizonte, Minas Gerais, Brazil
Tidal volume
Defined as the volume of air entering or exiting the lungs during each breath - in millilitres.
Time frame: Measure during the two non-invasive ventilation strategies. Tidal volume will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Respiratory rate
Breaths per minute
Time frame: Measure during the two non-invasive ventilation strategies. Respiratory rate will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Minute ventilation
Computed from tidal volume multiplied by respiratory rate, in liters/minute
Time frame: Measure during the two non-invasive ventilation strategies. Minute ventilation will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Mean inspiratory flow
Is a estimation of respiratory center drive activity. The higher its value, the greater the drive and vice-versa.
Time frame: Measure during the two non-invasive ventilation strategies. Mean inspiratory flow will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Labored Breathing Index (LBI)
This is a measure of chest wall coordination. This is the Labored Breathing Index (LBI) of a breath that takes into account phase and amplitude of the ribcage and abdomen traces. It is computed as the ratio of the sum of the integrals of the absolut values of the derivatives of the inspiratory limbs of ribcage and abdomen excursions divided by the corresponding integral of the derivative of the inspiratory limb of the tidal volume deflection. This measure of thoracoabdominal coordination is computed on a breath by breath basis. Perfect thoracoabdominal coordination produces an LBI of 1.0. In babies or adults who are relaxed and awake or in Quiet State, LBI lies between 1.0 and 1.2 but no systematic study of the normal values of LBI as a function of sleep stage and body posture has yet been undertaken. In Active State, thoracoabdominal discoordination generally is associated with elevated LBI values.
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Time frame: Measure during the two non-invasive ventilation strategies. Labor breathing index (LBI) will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Phase relation in inspiratory breathing (PhRIB)
This express the percentage agreement between direction of ribcage and abdomen movements during the inspiratory phase of breath.
Time frame: Measure during the two non-invasive ventilation strategies. Phase relation in inspiratory breathing will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Phase relation in expiratory breathing
This express the percentage agreement between direction of ribcage and abdomen movements during the expiratory phase of breath.
Time frame: Measure during the two non-invasive ventilation strategies. Phase relation in expiratory breathing will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Phase relation in total breathing
This express the percentage agreement between direction of ribcage and abdomen movements during the entire breath cycle.
Time frame: Measure during the two non-invasive ventilation strategies. Phase relation in total breathing will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.
Phase angle
The phase angle is computed from Lissajous loops between ribcage and abdomen excursions on a breath by breath basis.
Time frame: Measure during the two non-invasive ventilation strategies. Phase angle will be measured for 2 hours, one hour in continuous positive airway pressure and one hour in nasal intermittent positive pressure ventilation.