Diaphragm sniff ultrasound: Normal values, relationship with sniff nasal pressure and accuracy for predicting respiratory involvement in patients with neuromuscular disorders

Abstract

Background In patients with neuromuscular disorders, assessment of respiratory function relies on forced vital capacity (FVC) measurements. Providing complementary respiratory outcomes may be useful for clinical trials. Diaphragm sniff ultrasound (US) is a noninvasive technique that can assess diaphragm function that may be affected in patients with neuromuscular disorders. Purpose We aimed to provide normal values of sniff diaphragm ultrasound, to assess the relationship between sniff diaphragm US, vital capacity (VC) and sniff nasal pressure. Additionally, we aimed to evaluate the diagnostic accuracy of sniff diaphragm US for predicting restrictive pulmonary insufficiency. Materials and methods We included patients with neuromuscular disorders that had been tested with a sniff diaphragm US and functional respiratory tests. Healthy subjects were also included to obtain normal diaphragm sniff ultrasound. We performed diaphragm tissue Doppler imaging (TDI) and time movement (TM) diaphragm echography combined with sniff maneuver. Results A total of 89 patients with neuromuscular diseases and 27 healthy subjects were included in our study. In patients, the median age was 32 years [25; 50] and the median FVC was 34% of predicted [18; 55]. Sniff diaphragm motion using TM ultrasound was significantly associated with sniff nasal pressure, both for the right hemidiaphragm (r = 0.6 p <0.0001) and the left hemidiaphragm (r = 0.63 p = 0.0008). Right sniff peak TDI velocity was also significantly associated with FVC (r = 0.72, p<0.0001) and with sniff nasal pressure (r = 0.66 p<0.0001). Sniff diaphragm ultrasound using either TM mode or TDI displayed significant accuracy for predicting FVC<60% with an area under curve (AUC) reaching 0.93 (p<0.0001) for the right sniff diaphragm ultrasound in TM mode and 0.86 (p<0.001) for right peak diaphragm TDI velocity. Conclusion Sniff diaphragm TM and TDI measures were significantly associated with sniff nasal pressure. Sniff diaphragm TM and TDI had a high level of accuracy to reveal respiratory involvement in patients with neuromuscular disorders. This technique is useful to assess and follow up diaphragm function in patients with neuromuscular disorders. It may be used as a respiratory outcome for clinical trials.

Tissue Doppler Imaging of the Diaphragm in Healthy Subjects and Critically Ill Patients

“…In recent years, ultrasonography has been used extensively to evaluate diaphragmatic motion characteristics, such as excursion and thickening ( 1 ), with derived measurements repeatedly being shown to carry prognostic implications in the outcome of weaning ( 2 – 4 ). However, TDI of diaphragmatic tissue motion has been studied so far very little in adults ( 5 ); moreover, no information exists regarding the waveform pattern of diaphragmatic motion velocity and its reference values in healthy subjects and in ICU patients with respiratory failure.…”

M Mode Ultrasound and Tissue Doppler Imaging to Assess Diaphragm Feature in Late Onset Pompe Disease

“…In LOPD, clinically relevant diaphragm weakness may develop even in patients with little peripheral muscular impairment, causing nocturnal hypoventilation, supine dyspnea aggravation, daytime hypercapnia, fatigue and excessive daytime sleepiness [3]. Diaphragm we assessed the diaphragm motion using TM mode in rest and during a sniff maneuver, as previously described [5]. We found a paradoxical diaphragm motion during a sniff maneuver of both the right (−11 mm) and the left hemi diaphragm (−18 mm), with M mode (Figure 1).…”

VOX Index– A New Parameter Using Ultrasound to Predict Time of Applying Noninvasive Ventilation

“…function assessed by diaphragmatic ultrasound 6,17 . Physicians could perform real time assessment of patient's inspiratory muscle strength through monitoring the diaphragm thickness and movement distance, achieving early diagnosis of diaphragmatic atrophy and prediction of extubation outcomes in mechanically ventilated patients 14,15,20−22 .…”

“…The real time assessment can also be used to determine if NIV is needed for patients with dyspnea in the emergency department, further predicting the NIV outcome 12,16 . Despite the limited amount of studies regarding the velocity of diaphragm contraction, the great association between V D and inspiratory muscle strength has been demonstrated and used for extubation outcome prediction, which proved the reliability of V D 6,18 . In this study, we not only assessed the regular diaphragmatic ultrasound parameters, but also introduced a new index to better predict the need of NIV in ICU patients.…”

“…Transdiaphragmatic pressure (Pdi) is the traditional measure of diaphragm strength which is di cult to serve as a regular monitoring tool due to patient intolerance caused by the invasive technique 5 . Diaphragmatic ultrasound, on the contrary, has gained popularity in ICU as a new tool of assessing diaphragm functions providing its radiation free and noninvasive features [6][7][8][9][10] . Several studies have demonstrated the application of diaphragmatic ultrasound in predicting the NIV or extubation outcomes in ICU patients by measuring the diaphragm movement distance, velocity of contraction, thickness, and thickening fraction [11][12][13][14] .…”