None listed
Conditions
Brief summary
There are different schools of thought about how children/Tamariki with sick lungs should be ventilated (assisted by a machine). One strategy supported by the literature is called the “open lung strategy” in which we return the lungs to as normal a state as possible, while aiming to reduce the risks associated with assisted ventilation. There are many tests available to assess ventilated children/Tamariki, but the difficulty is that no test tells you when optimal ventilation has been reached. In this study we would use two simple tools to help indicate when the lungs are in as normal a state as possible, and hence improve our ability to ventilate these children/Tamariki. These tools (1) measure the pressure in the oesophagus, and (2) measure the change in lung volume during breathing by loosely placing stretchy bands around the chest and abdomen. Both have minimal risk. During this study of 12-20 children/Tamariki ventilated for lung problems in the Paediatric Intensive Care Unit, we would use the “open lung strategy” while measuring the responses obtained from these two tools. The only changes from standard care are to replace the feeding tube with one that measures pressure, to apply the stretchy bands and a sticky dot for monitoring.
Interventions
Measurement of transpulmonary pressure during stepped positive end expiratory pressure (PEEP) recuitment manoever on conventional mandatory ventilation (CMV) and high frequency oscillatory ventilation (HFOV). Children with severe ARDS will only be studied on HFOV.
Recruitment strategy - CMV. Tidal volume 6ml/kg with a rate enabling adequate carbon dioxide (CO2) clearance without autoPEEP. Inspired fraction of oxygen (FiO2) to permit oxygen saturation 85-92% in neonates and 92-96% in older chil
Measurement of transpulmonary pressure during stepped positive end expiratory pressure (PEEP) recuitment manoever on conventional mandatory ventilation (CMV) and high frequency oscillatory ventilation (HFOV). Children with severe ARDS will only be studied on HFOV. Recruitment strategy - CMV. Tidal volume 6ml/kg with a rate enabling adequate carbon dioxide (CO2) clearance without autoPEEP. Inspired fraction of oxygen (FiO2) to permit oxygen saturation 85-92% in neonates and 92-96% in older children. PEEP commenced at 5cmH2O. PEEP increased in increments of 2cm H2O at short intervals. Each step held until an oxygenation plateau is achieved. Measurements made at the end of each step. PEEP increased until oxygenation improves (the opening pressure). The lung will be considered recruited when either the FiO2 can be reduced to <0.4, or there are signs of overdistension. The PEEP will then be reduced in steps of 1cmH2O allowing plateauing of oxygenation and transcutaneous carbon dioxide [TcCO2] with measurement at the end of each step. The PEEP will be reduced until there is a significant reduction in oxygenation, compliance, or increase in TcCO2 (the closing pressure). Lung recruitment on HFOV will be performed with a frequency (Hertz) and amplitude appropriate for age and illness severity, and allowing adequate CO2 clearance. An FiO2 to permit previously described oxygen saturation parameters will be used. The mean airways pressure (MAP) will be commenced at 10cmH20, or at four above the MAP on CMV if previously CMV ventilated. The MAP will be increased and then decreased in steps of 2cmH2O as described above. The lung will then be recruited by increasing the PEEP / MAP to the previously noted opening pressure, then the PEEP / MAP will be reduced to 2cm above the closing pressure. The duration of the both the entire recruitment manoever and duration and number of individual steps will vary between patients, as the time to plateau at each step varies both between patients and with the lung pathology. The entire procedure takes between one and three hours.
Sponsors
Dr Jan Kelly
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
0 to 16 Years
Healthy volunteers
No
Inclusion criteria
Mechanically ventilated. Lung pathology fulfilling criteria for acute lung injury or acute respiratory distress syndrome.
Exclusion criteria
Children ventilated for an obstructive lung pathology. Children with raised intracranial pressure or a head injury.
Outcome results
None listed