In vitro comparison of performance including imposed work of breathing of CPAP systems used in low-resource settings

A Novel CPAP Device With an Integrated Oxygen Concentrator for Low Resource Countries: In Vitro Validation and Usability Test in Field

Goal: To develop and validatea novel neonatal non-invasive respiratory support device prototype designed to operate in low-resource settings. Methods: The device integrates a blower-based ventilator and a portable oxygen concentrator. A novel control algorithm was designed to achieve the desired fraction of inspired oxygen (FiO2) while minimizing power consumption. The accuracy of the delivered FiO2 and the device power consumption were evaluated in vitro, and a formative usability test was conducted in a rural hospital in Uganda. Results: The agreement between the set and delivered FiO2 was high (limit of agreement:-5.6 ÷ 3.8%). For FiO2 below 60%, the control algorithm reduced the power drain by 50%. The device was also appreciated by intended users. Conclusion: The prototype proved effective in delivering oxygen-enriched continuous positive airway pressure in the absence of compressed air and oxygen, holding promise for a sustainable and effective implementation of neonatal respiratory support in low-resource settings.

Bubble CPAP respiratory support devices for infants in low-resource settings

Approximately 46% of the 5.2 million annual under-5 deaths derive from neonatal conditions commonly associated with hypoxemia or acute respiratory distress. It has been estimated that 98% of these deaths occur in low- and middle-income countries (LMICs). Effective implementation of noninvasive respiratory support at all levels of healthcare could significantly reduce neonatal mortality. Several factors limit the widespread and effective implementation of noninvasive respiratory support in LMICs, including inadequate infrastructure, lack of proper instrumentation, shortage of skilled staff, costly disposables, and difficulties in the supply of consumables and spare parts. The aim of this state-of-the-art paper is to provide a detailed evaluation of the commercially available devices providing noninvasive respiratory support in LMICs, focusing on bubblecontinuous positive airway pressure (bCPAP). bCPAP might be administrated using a variety of different commercial devices, including devices specifically designed for LMICs, as well as using self-made systems. We described all the equipment required for safe and effective implementation of bCPAP, including air and oxygen sourced, pressure-reducing valves and flowmeters, air-oxygen blending systems, humidifiers, respiratory support devices, patient circuits, and airway interfaces. Specifically, we critically evaluated the advantages and disadvantages of various existing solutions within the context of low-resource settings.

Feasibility and usability of a very low-cost bubble continuous positive airway pressure device including oxygen blenders in a Ugandan level two newborn unit

BACKGROUND

Preterm birth and resulting respiratory failure is a leading cause of newborn death- the majority of which occur in resource-constrained settings and could be prevented with bubble continuous positive airway pressure (bCPAP). Commercialized devices are expensive, however, and sites commonly use improvised devices utilizing 100% oxygen which can cause blindness. To address this, PATH and a multidisciplinary team developed a very low-cost bCPAP device including fixed-ratio oxygen blenders.

OBJECTIVE

We assessed feasibility of use of the device on neonatal patients as well as the usability and acceptability of the device by healthcare workers. This study did not evaluate device effectiveness.

METHODS

The study took place in a Ugandan level two unit. Neonates with respiratory failure were treated with the bCPAP device. Prospective data were collected through observation as well as likert-style scales and interviews with healthcare workers. Data were analyzed using frequencies, means and standard deviation and interviews via a descriptive coding method. Retrospectively registered via ClinicalTrials.gov number NCT05462509.

RESULTS

Fourteen neonates were treated with the bCPAP device in October-December 2021. Patients were born onsite (57%), with median weight of 1.3 kg (IQR 1-1.8). Median treatment length was 2.5 days (IQR 2-6). bCPAP was stopped due to: improvement (83%) and death (17%). All patients experienced episodes of saturations >95%. Median time for device set up: 15 minutes (IQR 12-18) and changing the blender: 15 seconds (IQR 12-27). After initial device use, 9 out of 9 nurses report the set-up as well as blender use was "easy" and their overall satisfaction with the device was 8.5/10 (IQR 6.5-9.5). Interview themes included the appreciation for the ability to administer less than 100% oxygen, desire to continue use of the device, and a desire for additional blenders.

CONCLUSIONS

In facilities otherwise using 100% oxygen, use of the bCPAP device including oxygen blenders is feasible and acceptable to healthcare workers.

TRIAL REGISTRATION

ClinicalTrials.gov, Identifier NCT05462509.

Testing positive pressure delivered from commercial and WHO-style pediatric bubble CPAP devices

Background/aim

Low-cost commercial bCPAP devices have been deployed in resource-limited settings to treat neonatal respiratory failure. The use of these devices has increased access to pediatric respiratory support for infants. However, constrained resources may result in substitution of recommended consumables and/or use in older age groups. We hypothesized that commercially available bCPAP devices, the standard WHO-style device and various improvised adaptations would all generate effective, safe positive pressure at the patient interface.

Methods

Performance of 2 commercially available bCPAP devices was tested against the standard WHO-style bCPAP device, as well as several improvised modifications of these devices, by measuring positive pressure delivered at the patient interface. Variables tested included different flow rates, patient interfaces and respiratory circuit tubing.

Results

Both commercial devices utilized according to manufacturer recommendations generated the expected positive pressure at the patient interface. When testing the recommended WHO-style bCPAP device with recommended materials as well as other improvised modifications, we found variable and potentially unpredictable generation of positive pressure at the patient interface.

Conclusions

Modified or improvised bCPAP devices should be used with extreme caution as the support provided may be more or less than expected depending on respiratory tubing and flow rates employed. Our data support the effectiveness of bCPAP in newborns and young infants. But, to our knowledge, there are no bCPAP patient interfaces for older children effective with low liter flow devices. Therefore, based on these results, we recommend against using WHO-style bCPAP devices for non-infant patients with respiratory failure and instead recommend using standard oxygen therapy with nasal cannulae or face-masks, as well as early consideration of transfer to a higher level of care.

Evaluation of a Bubble CPAP System for Low Resource Settings

BACKGROUND

Despite its established safety, efficacy, and relative simplicity, CPAP treatment is not widely available for newborns and infants in low- and middle-income settings. A novel bubble CPAP system was designed to address the gaps in quality and accessibility of existing CPAP systems by providing blended, humidified, and pressurized gases without the need for electricity, compressed air, or manual power. This was the first study that tested the performance of the system with a simulated patient model. METHODS: In a spontaneously breathing 3-dimensional printed nasal airway model of a preterm neonate, CPAP performance was assessed based on delivered pressure, oxygen level, and humidity at different settings. RESULTS: Preliminary device performance characteristics were within 5% among 3 separate devices. Performance testing showed accurate control of CPAP and oxygen concentration at all settings with the bubble CPAP system. Lung model pressure and oxygen concentration were shown to stay within ±0.5 cm H₂O and ±4% of full scale of the device settings, respectively, with relative humidity > 80%. CONCLUSIONS: Performance testing of the bubble CPAP system demonstrated accurate control of CPAP and oxygen concentration with humidity levels suitable for premature newborns on noninvasive support.