AVALIAÇÃO DA PRECISÃO E ESTABILIDADE DO FLUXO DE OXIGÊNIO MEDICINAL ATRAVÉS DE FLUXÔMETRO ANALÓGICO E DIGITAL SOB VARIAÇÃO DE PRESSÃO NA REDE DE GASES MEDICINAIS.

Introduction: Oxygen therapy is essential in clinical practice, requiring flow accuracy to avoid hypoxemia and hyperoxia, which pose significant risks to the patient. Conventional analog flowmeters are susceptible to pressure variations in the medical gas network, compromising their accuracy. This study evaluates the accuracy and stability of the digital device compared to an analog flowmeter under variable pressure conditions. Methods: Controlled laboratory tests were performed comparing the ATAS O₂ with an analog ball flowmeter. Accuracy was assessed by varying the network inlet pressure (3.5, 5, and 7 kgf/cm²) and the flow (1 to 7 L/min). Statistical analysis included paired t-test, ANOVA, Chi-square test, and linear regression, with p < 0.05. Results: The ATAS O₂ demonstrated significantly superior accuracy and stability. Its mean error increased smoothly with pressure. In contrast, the analog flowmeter exhibited a rapid and steep increase in error as pressure varied. The differences between the devices were statistically significant (p < 0.01 at 3.5 kgf/cm²; p < 0.001 at 5 and 7 kgf/cm²), confirming the interaction between flowmeter type and pressure on the magnitude of the error. The analog flowmeter showed a dramatically higher frequency of out-of-tolerance measurements (p < 0.001) and a strong tendency for error to increase with increasing flow and pressure. Conclusion: The digital flowmeter offers a robust and reliable solution for accurate oxygen administration, especially in networks with pressure fluctuations.