THE PERCUSSIONAIRE® UNIVERSAL TRANSPORT (LOGISTICAL) VENTILATORS -
During the initial pioneering of civil aviation helicopter and fixed wing aircraft for intensive care transport, the majority of the aircraft were dedicated to medical transport only. Thus the majority of Dr. Bird’s early civil intensive care ventilator transport installations were designed into the dedicated aircraft. The built-in aircraft installations restricted the use of the expensive aircraft to medical transport only, which could create an economic hardship for a small aircraft operator. The weight and size of intensive care ventilatory devices is a major consideration in small commercial helicopters and fixed wing aircraft.
As the use of helicopter and fixed wing medical transport aircraft proliferated, the demand for a small mobile transport ventilator capable of effectively ventilating the smallest neonate through pediatrics to large adults increased. The basic criteria for a ventilatory device and oxygen supplies had to be capable of providing cardio-respiratory support to the most critical patient equal to or better than that available in the hospital critical care facilities. Portable oxygen supplies had to be compatible with the time in the air as well as from the site of trauma to the institutional critical care facility with a calculated reserve.
To satisfy these requirements, Dr. Bird employed the mini TXP® Military Transporter® ventilators which are capable of effectively ventilating any patient capable of being mechanically ventilated. Under certain helicopter trauma response conditions, especially in vehicular accidents, there could be a mother and a child requiring cardio-respiratory critical care ventilatory support.
To meet these requirements, Dr. Bird developed a transport package called a Duotron® which would meet the criteria for the “critical care transport in small
airborne vehicles such as helicopters”
 The DUOTRON CONSISTED OF TWO TXP® TRANSPORTER® VENTILATORS, WITH A COMMON OXYGEN SUPPLY, ATTACHED BY MEANS OF A SADDLE.
One ventilator was programmed as a conventional time cycled (volume oriented) CMV ventilator with tidal delivery rates from under 5 to over 50 breaths per minute. The other, companion ventilator, was programmed for higher frequency percussive ventilation with sub tidal delivery frequencies of from about 50 to over 400 breaths per minute.
The I/E or i/e ratios at the selected frequencies were automatically controlled from 1:1 at the highest selected frequency to over 1:4 at the lowest selected frequency. Breathing rate selection is controlled by a single control knob.
© Bird Institute of Biomedical Technology 2005 page
1
The regulated oxygen source pressure was pre-set at 40 psig. Selectable Inspiratory FLOWRATE during the selected inspiratory time determined the patient’s tidal exchange during the programmed inspiratory time.
Push button manual inspiration provided for override of any ventilatory program.
THE TXP® TRANSPORTER® VENTILATORS ARE ALL TIME CYCLED. That is, at a selected regulated operational source pressure of a given FIO 2, the inspiratory time is determined by the cycling rate selected. Tidal volume is directly controlled by FLOW x TIME. Therefore, the TXP® is a miniaturized volume oriented ventilator with the mechanical integrity equivalent to or better than any other critical care ventilator used in any institutional ICU.
In a basic conventional volume oriented intensive care ventilator (CMV), a tidal volume is selected to be delivered under a scheduled peak delivery pressure (PIP). Thus, either the ventilator will first cycle on volume delivery or second on the selected PIP. Under these conditions, when the CONSTANT INSPIRATORY FLOWRATE is resisted by intrapulmonary resistances, the INSPIRATORY FLOW is converted into an INTRAPULMONARY PRESSURE RISE. This is the most common form of barotrauma during the mechanical ventilation of the lung.
 As is apparent, the thickness of the alveolar wall decreases with inspiratory lung inflation then increases with expiratory lung deflation.
Primarily, the potential decrease in inspiratory alveolar wall thickness is factored by preferential airway and the sustenance of an inflational pressure aggravated by a Penduluft effect.
© Bird Institute of Biomedical Technology 2005 page
2
THE RUGGEDIZED PHASITRON IS A VENTILATOR IN ITSELF
The unique lung protective strategy employed to minimize potential barotrauma as a component of the TXP® design logic is accommodated by Dr. Bird’s Phasitron® physical physiological interface. Essentially, the Phasitron
® is an air clutch that modifies the constant time cycled inspiratory flowrate from the TXP® ventilator into a variable inspiratory flowrate responding in milliseconds to changes in endobronchial airway resistances.
Essentially, the Phasitron, servoed by a remote fluidic device, is in itself a ventilator at the patient’s proximal airway. The peak jet pressure of the ambient
vented venturi jet will determine the available PIP.
Dynamically, (like a volume oriented ventilator) the Phasitron® proximal airway delivery pressure (at any instant of inspiratory time) will be controlled by intrapulmonary resistances to inflow up to the PIP determined by the peak venturi jet pressure. Therefore, any fourth generation fluidic ventilatory device conceived by Dr. Bird has a major lung protective strategy.
© Bird Institute of Biomedical Technology 2005 page
3
The high frequency percussive delivery serves to minimize the potential for a sustained mechanically induced proximal airway pressure rise capable of potentiating barotrauma. As inspiratory time is increased with slower tidal volume delivery rates (with longer sustained inspiratory peak pressures), the lung protective strategy is maintained by fluidic clutching within the Phasitron venturi.
The Duotron was capable of using separate breathing circuits for mother and child transport by employing two breathing circuits. Nominally, the mother would be ventilated with the TXP® with typical CMV programming, and the child with the TXP® programmed for high frequency percussive ventilation.
© Bird Institute of Biomedical Technology 2005 page 4
In order to maintain maximum oxygen economy with a degree of humidification during transport, the breathing circuit was humidified by a wet gun cotton wick inside the entrainment tubing in lieu of an artificial nose.
When the two high and low frequency TXP ® ventilators deliver into a common Phasiton, a combined diffusive convective ventilation could be programmed for (a form of) high frequency percussive ventilation sufficient to maintain the most critical cardio-pulmonary patients.
SEVERAL OF THE AVAILABLE MIXED DUOTRON® PROGAMS
© Bird Institute of Biomedical Technology 2005 page
5
After the success of the Duotron®, the system was re-packaged to facilitate logistical requirements of the twin TXP ® configurations. This unit became the UNIVERSAL BRONCHOTRON® Multi-Mode Ventilator.
The Bronchotron® has maintained the dual functional features of the Duotron® with more organized containment in a common housing. Re-packaging has allowed integration of a standard TIME CYCLED CMV ventilator  with access to both inspiratory and expiratory time and inspiratory flowrate, thus enabling UNIVERSAL VENTILATION of neonates through pediatrics to large adults as well as providing a universal High Frequency Percussive IPV Therapy ventilator.
The universal Bronchotron® can serve logistically, or as a universal acute care institutional critical care ventilator capable of providing for secretion mobilization and raising in the most challenging neonatal through pediatric to large adult patients with acute airway obstructions.
© Bird Institute of Biomedical Technology 2005 page
6
The universal Bronchotron® can provide for effective Time Cycled CMV ventilation in any lung capable of being mechanically ventilated.
The Phasitron® will deliver time cycled (volume oriented) CMV against pulmonary structures with reduced gross pulmonary compliance. PIP can be regulated by operational pressure selection (with fluidic clutching) in lieu of pressure limiting “pop off” provisions.
When the Bronchotron® is programmed with combined high frequency percussive oscillation enhanced by periodic CMV convective deliveries, a sinusoidal type of ventilation is created.
© Bird Institute of Biomedical Technology 2005 page 7
The combined endobronchial mechanical gas mixing (diffusion) with a convective tidal (convective) exchange is called High Frequency Percussive Ventilation (HFPV ™).
The pulmonary Functional Residual Capacity (FRC) can be mechanically increased by Dynamic Functional Residual Capacity (D/FRC), without PEEP or CPAP, by decreasing the expiratory time to deliver the successive tidal volumes before the peripheral pulmonary structures are deflated to the point of collapse.
Variations of packaging allow the Bronchotron® ventilators to be panel mounted for installations in neonatal incubators, emergency vehicles or dispensaries.
NOTES:
© Bird Institute of Biomedical Technology 2005 page 8
«
Go Back
|
