Effective Gas Exchange in Paralyzed Juvenile Rabbits Using Simple, Inexpensive Respiratory Support Devices

Abstract

ABSTRACT:We have developed two devices: a high-amplitude bubble continuous positive airway pressure (HAB-CPAP) and an inexpensive bubble intermittent mandatory ventilator (B-IMV) to test the hypotheses that simple, inexpensive devices can provide gas exchange similar to that of bubble CPAP (B-CPAP) and conventional mechanical ventilation (CMV). Twelve paralyzed juvenile rabbits were intubated, stabilized on CMV, and then switched to CPAP. On identical mean airway pressures (MAPs), animals were unable to maintain pulse oximeter oxygen saturation (SpO 2 ) Ͼ80% on conventional B-CPAP, but all animals oxygenated well (97.3 Ϯ 2.1%) on HAB-CPAP. In fact, arterial partial pressures of O 2 (PaO 2 ) were higher during HAB-CPAP than during CMV (p ϭ 0.01). After repeated lung lavages, arterial partial pressures of CO 2 (PaCO 2 ) were lower with B-IMV than with CMV (p Ͻ 0.0001), despite identical ventilator settings. In lavaged animals, when HAB-CPAP was compared with CMV at the same MAP and 100% O 2 , no differences were observed in PaO 2 , but PaCO 2 levels were higher with HAB-CPAP (70 Ϯ 7 versus 50 Ϯ 5 mm Hg; p Ͻ 0.05). Arterial blood pressures were not impaired by HAB-CPAP or B-IMV. The results confirm that simple inexpensive devices can provide respiratory support in the face of severe lung disease and could extend the use of respiratory support for preterm infants into severely resourcelimited settings. (Pediatr Res 68: 526-530, 2010) I nfant mortality caused by respiratory distress syndrome in the United States decreased from ϳ268 in 100,000 live births in 1971 to 98 in 100,000 live births in 1985 (1) and 17 in 100,000 live births in 2007 (2). The decrease in mortality from 1971 to 1985 was, in large part, due to the development and widespread availability of mechanical ventilators and continuous positive airway pressure (CPAP) devices designed to assist lung recruitment and gas exchange in newborn infants in respiratory distress. However, Ͼ4 million infants die throughout the world each year, with 1 million dying principally from respiratory insufficiency (3,4), largely because of the lack in resource-limited countries of the respiratory support devices and technologies that are commonly used in more affluent societies.Modern ventilators are expensive to purchase, which limits availability in resource-limited countries. Even if the devices are donated, the need for highly trained personnel to operate, maintain, and repair the ventilators effectively prevent significant use of modern ventilators in most facilities. Practical methods for respiratory support of prematurely born infants could save hundreds of thousands of newborn lives each year.In an effort to bridge the gap between the need for less expensive, simpler, more practical approaches to respiratory support and the need for greater range of simple support methods, we have developed two novel devices that can be used separately or together to provide a broad range of respiratory support for infants.One device, termed high-amplitude bubble continuous positive...

Comparison of Bubble CPAP Devices Using RAM Cannula for Extubation Failure in Very Low Birth Weight Infants: Randomized and Cohort Studies

“…Homemade bCPAP devices and other devices with single outlet without diffusers (Fisher and Paykel) have larger fluctuations in pressure amplitudes (±2.2 cm H 2 O) than the B&B Bubbler © , and these fluctuations can change gas exchange volumes [4]. The pressure fluctuations can be further increased (Seattle-PAP) by adding an angled extension to the underwater tube [12]. Seattle-PAP can maintain ventilation in paralyzed, saline-lavaged rabbits on bCPAP, lowered breathing effort in infants, and is currently in a randomized trial (NCT03085329) [12, 20].…”

“…The pressure fluctuations can be further increased (Seattle-PAP) by adding an angled extension to the underwater tube [12]. Seattle-PAP can maintain ventilation in paralyzed, saline-lavaged rabbits on bCPAP, lowered breathing effort in infants, and is currently in a randomized trial (NCT03085329) [12, 20]. The similarities between devices may have negated any bubble effects, and other devices with more exaggerated pressure fluctuations could have different results.…”

“…The size and angulation of the exhalation limb in a bCPAP system affects the degree of pressure variation [4, 11]. bCPAP devices that create bigger oscillatory bubbles with more “noise” result in better oxygenation and decreased work of breathing [12], and higher CPAP is generated from vigorous, high-amplitude bubbling than slow bubbling at lower flow rates [13]. A bCPAP device with a single outlet exhalation tube, the B&B Bubbler © , may create larger bubbles and oscillatory noise, and resembles the devices used in units with low BPD rates [1, 2].…”

Neonatal Mortality From Respiratory Distress Syndrome: Lessons for Low-Resource Countries

“…Much work is already being done to make these interventions more easily adaptable and economical in low-resource settings. [65][66][67][68] The introduction of these technologies to the settings close to where most infants are born, such as local clinics, would save the most newborn lives. However, CPAP would be problematic without trained personnel, a supporting infrastructure, and innovative designs for resource-poor settings.…”

Neonatal Noninvasive Ventilation Techniques: Do We Really Need to Intubate?

“…93 In addition, high-amplitude bubble CPAP provided noninvasive support, via bi-nasal prongs, to spontaneously breathing, lung-lavaged juvenile rabbits with lower WOB (P Ͻ .001) and higher P aO 2 (P ϭ .007) than were observed in the same animals supported with bubble CPAP at identical mean airway pressures. 91 Two rabbits supported by high-amplitude bubble CPAP became apneic, with normal P aCO 2 and vital signs. High-amplitude bubble CPAP may represent a relatively simple new strategy for supporting a greater fraction of neonates who would otherwise fail CPAP and require invasive ventilation.…”