Ultrasound Assessment of Diaphragm Function in Traumatic Brain Injury: A Prospective Observational Study

Abstract

Abstract Background Prolonged mechanical ventilation is associated with weaning failure in severe TBI patients. Ultrasound is a noninvasive modality for evaluating diaphragm function. On ultrasonography (USG), diaphragm thickness is observed to decrease over time in mechanically ventilated patients. However, little literature exists on the severity of diaphragmatic dysfunction in traumatic brain injury (TBI) patients. This study aimed to observe the changes occurring in diaphragmatic function in mechanically ventilated TBI patients. Methods TBI patients aged 18 to 65 years, requiring mechanical ventilation, were included. USG assessment of diaphragm function was done on days 0, 3, 5 and 7 of neurotrauma intensive care unit (NICU) admission in the supine position, during sedation holiday and spontaneous breathing trial. Measurements were done at end expiration (TE) and at maximal inspiration (TI) using 7- to 13-MHz linear array probe for three consecutive times and then averaged. Thickness fraction was calculated as (TI – TE/TE) × 100. Diaphragmatic excursion (DE) was measured in the M mode using 1- to 5-MHz phased array probe, as maximal height of inspiration. Results Forty patients were evaluated. The mean diaphragmatic thickness fraction (DTF) at days 0, 3, 5, and 7 was 33.58 ± 10.08, 33.4 ± 9.76, 32.32 ± 8.36, and 31.65 ± 8.23, respectively. Change in DTF was statistically significant on day 7 (p = 0.040). The mean DE at days 0, 3, 5, and 7 was 9.61 ± 3.99, 9.02 ± 3.46, 8.87 ± 2.63, 8.56 ± 2.74, respectively. Changes in DE over days 3, 5, and 7 were statistically significant (p < 0.001). The mean DTF was lower on day 3 in patients who were admitted for less than 20 days than those who required hospital admission for more than 20 days (p = 0.044). Conclusion Decrease in DTF and DE over the period of 7 days was observed with a significant decrease occurring on the 7th day following TBI.