Please see Bibliography of References for a list of abstracts, manuscripts and posters.
Borrat X, Mercadal J, Benito S, Adalia R, Zavala E, Tercero J. Crit Care. 2009;13(Suppl 1):P026.
Introduction: Unnecessary prolongation of mechanical ventilation(MV) is related to increased morbility. On the contrary early discontinuation of MV with reintubation is also related to bad prognosis. High respiratory-cardiac load, neuromuscular dysfunction are known factors related to weaning failure. Oxygen tissue saturation(StO2) obtained by near infrared spectroscopy(NIRS) reflects the balance between oxygen delivery and consumption at muscle level. StO2 evolution during weaning may have a role in assessing respiratory muscle performance and help us to predict patient readiness to be weaned. The objective is to describe respiratory muscle StO2 during a T-tube test.
Methods: A patient with mild head injury and pulmonary contussion was submitted to a T-Tube trial after obtaining stability on day five. NIRS signal from serratus anterior muscle was acquired by placing Inspectra device probe on the skin surface of the muscle. Simultaneously respiratory, heart rate, mean arterial pressure and arterial oxygen saturation were recorded.
Results: After 5min the patient failed on his first T-tube trial showing profuse sweating, accessory muscles recruitment and increasing respiratory rate and mean arterial pressure. StO2 signal decreased during ventilatory failure until the patient was on assistance again.
Conclusions: NIRS was sensitive to respiratory muscles fatigue but further research is in process to asses its predictive capability.
References: Moalla W et al. Respiratory muscle deoxygenation and ventilatory threshold assesments using near infrared spectroscopy in children. Int J Sports Med 26:576-82;2005.
Image 1: StO2 evolution during T-tube trial