Fluxo de saída de oxigênio fornecido por reanimadores manuais com balão auto-inflável em pacientes com ventilação espontânea

Abstract

Objective: To determine the oxygen outflow delivered by seven different models of manually operated self-inflating resuscitation bags (with and without an oxygen reservoir connected), which were tested using different oxygen supply rates without manipulating the bag, by simulating their use in patients breathing spontaneously. Methods: The oxygen outflow was measured using a wall oxygen flow meter and a flow meter/respirometer attached to the bag, together with another flow meter/respirometer attached to the patient connection port. The resuscitation bags that allow the connection of an oxygen reservoir were tested with and without this device. All resuscitation bags were tested using oxygen supply rates of 1, 5, 10, and 15 L/min. Statistical analyses were performed using analysis of variance and t-tests. Results:The resuscitation bags that allow the connection of an oxygen reservoir presented a greater oxygen outflow when this device was connected. All resuscitation bags delivered a greater oxygen outflow when receiving oxygen at a rate of 15 L/min. However, not all models delivered a sufficient oxygen outflow even when the two previous conditions were satisfied. Conclusions: Of the resuscitation bags studied, those that allow the connection of an oxygen reservoir must have this reservoir connected to the bag when used as a source of oxygen in nonintubated spontaneously breathing patients. All of the models studied should receive oxygen at a rate ≥ 15 L/min. It is not safe to use manually operated self-inflating resuscitation bags for this purpose without knowing their characteristics. ResumoObjetivo: Determinar o fluxo de saída de oxigênio fornecido por sete modelos diferentes de reanimadores manuais com balão auto-inflável (com e sem reservatório de oxigênio acoplado), que foram testados utilizando-se diferentes fluxos de entrada de oxigênio sem manipular o balão, simulando o uso em pacientes com respiração espontânea. Métodos: O fluxo de saída de oxigênio foi medido utilizando-se um fluxômetro de oxigênio de parede e um fluxômetro/respirômetro conectados ao balão e outro fluxômetro/respirômetro conectado à porta de conexão do paciente. Os reanimadores que permitem o acoplamento de um reservatório de oxigênio foram testados com e sem esse reservatório. Todos os reanimadores foram testados utilizando-se fluxos de entrada de oxigênio de 1, 5, 10 e 15 L/min. Para a análise estatística utilizaram-se análise de variância e o teste t. Resultados: Os reanimadores que permitem o acoplamento de um reservatório de oxigênio apresentaram maior fluxo de saída de oxigênio quando esse dispositivo estava acoplado. Todos os reanimadores forneceram maior fluxo de saída de oxigênio quando receberam 15 L/min de oxigênio. Entretanto, nem todos os modelos testados forneceram fluxo de saída de oxigênio suficiente mesmo quando as duas condições anteriores foram atendidas. Conclusões: Dos reanimadores estudados, os que permitem o acoplamento de um reservatório de oxigênio devem obrigatoriamente estar com esse reservatório ac...

From Mouth-to-Mouth to Bag-Valve-Mask Ventilation: Evolution and Characteristics of Actual Devices—A Review of the Literature

“…An air volume is provided to the patient when the rescuer squeezes the bag. These different parts are depicted in Figure 1 [11]. …”

“…BVM systems with nonrebreathing valves can be used either in controlled ventilation or in spontaneous ventilation to keep or to increase patient arterial oxygen blood pressure prior to intubation [11, 18]. However, according to Tibballs et al, some devices with a “duckbill” valve should not be used to provide oxygen during spontaneous ventilation.…”

“…However, “duckbill” valves did not reliably prevent air entrainment [19]. It remains, therefore, important to know the BVM characteristics before the use on a patient breathing spontaneously [11]. …”

Evaluation of manual resuscitators used in ICUs in Brazil

“…( 1 , 2 ) Being used in ICUs in order optimize oxygenation and facilitate the removal of secretion in patients on invasive mechanical ventilation, MRs are also used for intra-hospital transport and as a source of temporary ventilation in intubated and nonintubated patients. ( 1 - 4 ) On the basis of their inflation mechanism, MRs can be classified as self-inflating or flow-inflating, ( 1 , 5 ) the former being the most commonly used type in ICUs in Brazil.…”

“…( 5 , 6 ) When the bag is compressed by the operator, the patient valve occludes the expiratory port and allows the air within the bag to flow to the patient; when the pressure within the bag ceases, the patient valve returns to its normal position, occluding the communication of the bag with the patient and allowing the air coming from the patient to be exhaled through the expiratory port. A drop in pressure within the bag during exhalation causes the inflating valve to open, allowing the air to enter the bag.…”