Comparação entre três métodos de obtenção do índice de respiração rápida e superficial em pacientes submetidos ao desmame da ventilação mecânica Comparison among three methods to measure the rapid shallow breathing index in patients submitted to weaning from mechanical ventilation

Abstract

JUSTIFICATIVA E OBJETIVOS: Esta pesquisa justifica-se na necessidade de maior conhecimento a respeito das técnicas de desmame ventilatório utilizadas em pacientes sob ventilação mecânica prolongada. O objetivo deste estudo foi comparar a obtenção do índice de respiração rápida e superficial (IRRS) nas modalidades PSV de 10 cmH2O e PEEP de 5 cmH2O (PSV10); CPAP de 5 cmH2O (CPAP5) e em ventilação espontânea (ESP), correlacionando com sucesso ou insucesso na retirada da ventilação mecânica (VM). MÉTODO: Estudo prospectivo incluindo 54 pacientes em VM há mais de 48 horas, submetidos ao IRRS em três modos ventilatórios: PSV10, CPAP5 e ESP nos momentos pré e pós-nebulização, utilizando tubo-T. Os pacientes foram retirados da VM quando o IRRS era BACKGROUND AND OBJECTIVES: To compare the attainment of the rapid shallow breathing index (IRRS) in modalities PSV 10 cmH2O and PEEP 5 cmH2O (PSV10), CPAP 5 cmH2O (CPAP5) and spontaneous breathing (SB), correlating them with success on failure in the withdrawal of mechanical ventilation (MV). METHODS: Prospective study including 54 patients in MV > 48 hours, submitted to the IRRS in three ventilatory modalities: PSV10, CPAP5 and SB at the moments before and after T-tube spontaneous breathing. The patients were removed from MV when IRRS was < 105. RESULTS: There wasn't statistically significant difference between IRRS values at the moments before and after T-tube SB. There was statistically significant difference IRRS value between the modalities CPAP5 and PSV10 (p = 0.008), and between the modalities SB and PSV10 (p = 0.01) at the moment before T-Tube SB and of IRRS value, gotten between CPAP5 and PSV10 (p = 0.01) at the moment after T-tube SB. CONCLUSIONS: From this sample, it can be observed that IRRS values are overestimated when gotten in modality PSV10. It was also evidenced that there is no need of a 30 min T-tube SB before extubation, when the weaning is performed with the technique of gradual reduction of PSV. This study suggested that IRRS is able to predict weaning success; however it is not able to determine failure when it was < 105. It is recommended that IRRS must be analyzed in association with other predictive weaning parameters.

Keywords

• desmame
• índice de respiração rápida e superficial
• ventilação com pressão de suporte
• ventilação mecânica
• tubo-T
• mechanical ventilation
• pressure support ventilation
• rapid shallow breathing index
• T-tube
• weaning