Oxygen Blending is Urgently Needed in Resource-Limited Settings

Addressing the gap in preterm resuscitation practices in high-income and low-middle income countries: a multicenter survey of the Asian neonatal network collaboration

Background

Optimum neonatal resuscitation practices are vital for improving neonatal survival and neurodevelopment outcomes, particularly in extremely preterm infants. However, such practices may vary between high-income countries (HICs) and low-middle-income countries (LMICs). This study aimed to evaluate the resuscitation practices of high-risk infants in a large multi-country sample of healthcare facilities among HICs and LMICs in Asia under the AsianNeo Network.

Methods

In 2021, a customized 6-item online survey on resuscitation practices of infants born at <29 weeks gestation (or birth weight <1,200 g) was sent by the representative of each country's neonatal network to all the Neonatal Intensive Care Units (NICUs) participating in AsianNeo network. At the time of the survey, there were 446 participating hospitals in eight countries: four high-income countries (Japan, Singapore, South Korea, and Taiwan) and four low-middle-income countries (Malaysia, Indonesia, Philippines, and Thailand).

Results

The study included 446 hospitals, with a response rate of 72.6% (ranging from 62.7% to 100%), with 179 (55.2%) in HICs and 145 (44.7%) in LMICs. Routine attendance of experienced NICU physicians during resuscitations is reported to be higher in HICs than LMICs, both during daytime (79% vs. 40%) and nighttime (62% vs. 23%). The NRP guidelines in each country were varied, with 4 out of 8 countries using indigenously developed guidelines. Equipment availability during resuscitation was also variable; saturation monitors, radiant warmers, and plastic wraps were available in almost all hospitals, whereas oxygen and air blenders, heated humidified gas, and end-tidal CO2 detectors were more available in HICs. The most common device for Positive Pressure Ventilation (PPV) was the T-piece resuscitator (52.3%).

Conclusion

The neonatal resuscitation practices for extremely preterm infants, encompassing staff, equipment, and guidelines, exhibited variance between HICs and LMICs in the AsianNeo region. Further enhancements are imperative to narrow this gap and optimize neonatal outcomes.

Optimizing Oxygen Delivery by Low-Flow Nasal Cannula to Small Infants: A Bench Study

BACKGROUND

In infants treated with a low-flow nasal cannula (LFNC), the oxygen concentration delivered to the lungs (i.e., the effective FiO2) is difficult to estimate. The existing mathematical formulas rely on important assumptions regarding the values of respiratory parameters and, thus, may be inaccurate. We aimed to assess oxygen delivery by LFNC to small infants using realistic simulations on a mechanical breathing model.

METHODS

A mechanical breathing simulator (infant upper-airway replica, single-space breathing compartment, electric motor, microcontroller) was developed. Breathing simulations (n = 1200) were performed at various tidal volume (VT), inspiratory time (Ti), and respiratory rate (RR) combinations and different cannula flows.

RESULTS

Minute ventilation (MV) was the most significant predictor of effective FiO2. FiO2 was higher at lower VT and higher Ti values. Benaron and Benitz's formula underestimated the effective FiO2 at lower MV values, while Finer's formula significantly overestimated it. A set of predictive FiO2 charts was developed based on cannula flow, infant body weight, and RR.

CONCLUSIONS

The effective FiO2 delivered by LFNC to small infants critically depends on VT, Ti, and RR. However, since VT and Ti values are not available in clinical practice, the existing mathematical formulas may be inaccurate. Our novel predictive FiO2 charts could assist in optimizing oxygen delivery by LFNC using easy-to-obtain parameters, such as infant body weight and RR.

Air–Oxygen Blenders for Mechanical Ventilators: A Literature Review

Respiratory diseases are one of the most common causes of death in the world and this recent COVID-19 pandemic is a key example. Problems such as infections, in general, affect many people and depending on the form of transmission they can spread throughout the world and weaken thousands of people. Two examples are severe acute respiratory syndrome and the recent coronavirus disease. These diseases have mild and severe forms, in which patients gravely affected need ventilatory support. The equipment that serves as a basis for operation of the mechanical ventilator is the air–oxygen blender, responsible for carrying out the air–oxygen mixture in the proper proportions ensuring constant supply. New blender models are described in the literature together with applications of control techniques, such as Proportional, Integrative and Derivative (PID); Fuzzy; and Adaptive. The results obtained from the literature show a significant improvement in patient care when using automatic controls instead of manual adjustment, increasing the safety and accuracy of the treatment. This study presents a deep review of the state of the art in air–oxygen benders, identifies the most relevant characteristics, performs a comparison study considering the most relevant available solutions, and identifies open research directions in the topic.

Evaluation of an innovative low flow oxygen blender system for global access

BACKGROUND

Safe and effective oxygen delivery methods are not available for the majority of infants and young children globally. A novel oxygen blender system was designed to accurately deliver concentration-controlled, oxygen-enriched air to hypoxemic children up to age five. The system does not require compressed medical air, is compatible with both oxygen tanks and oxygen concentrators, and is low cost. This is the first study that tested the performance of the innovative oxygen blender system.

METHODS

The performance of the oxygen blender system was assessed in vitro based on delivered oxygen levels and flow rates with an oxygen tank, an oxygen tank using a nasal occlusion model, and an oxygen concentrator.

RESULTS

The measured %O₂ of the performance test was within ± 5% of full scale (FS) of the target value across all flows and all nasal cannulas. Occlusion testing demonstrated that 50% occlusion did not significantly affect the system outputs. The oxygen blender system was shown to be compatible with both oxygen tanks and oxygen concentrators.

CONCLUSIONS

The novel oxygen blender system accurately controls oxygen concentrations and blended air flow rates, and is compatible with both oxygen tanks and oxygen concentrators. This innovation may be an opportunity for improved infant and child oxygen treatment worldwide.