Ultrasound evaluation of diaphragm function in mechanically ventilated patients: comparison to phrenic stimulation and prognostic implications

Background The relationship between the diaphragm thickening fraction and the transdiaphragmatic pressure, the reference method to evaluate the diaphragm function, has not been clearly established. This study investigated the global and intraindividual relationship between the thickening fraction of the diaphragm and the transdiaphragmatic pressure. The authors hypothesized that the diaphragm thickening fraction would be positively and significantly correlated to the transdiaphragmatic pressure, in both healthy participants and ventilated patients. Methods Fourteen healthy individuals and 25 mechanically ventilated patients (enrolled in two previous physiologic investigations) participated in the current study. The zone of apposition of the right hemidiaphragm was imaged simultaneously to transdiaphragmatic pressure recording within different breathing conditions, i.e., external inspiratory threshold loading in healthy individuals and various pressure support settings in patients. A blinded offline breath-by-breath analysis synchronously computed the changes in transdiaphragmatic pressure, the diaphragm pressure-time product, and diaphragm thickening fraction. Global and intraindividual relationships between variables were assessed. Results In healthy subjects, both changes in transdiaphragmatic pressure and diaphragm pressure-time product were moderately correlated to diaphragm thickening fraction (repeated measures correlation = 0.40, P < 0.0001; and repeated measures correlation = 0.38, P < 0.0001, respectively). In mechanically ventilated patients, changes in transdiaphragmatic pressure and thickening fraction were weakly correlated (repeated measures correlation = 0.11, P = 0.008), while diaphragm pressure-time product and thickening fraction were not (repeated measures correlation = 0.04, P = 0.396). Individually, changes in transdiaphragmatic pressure and thickening fraction were significantly correlated in 8 of 14 healthy subjects (ρ = 0.30 to 0.85, all P < 0.05) and in 2 of 25 mechanically ventilated patients (ρ = 0.47 to 0.64, all P < 0.05). Diaphragm pressure-time product and thickening fraction correlated in 8 of 14 healthy subjects (ρ = 0.41 to 0.82, all P < 0.02) and in 2 of 25 mechanically ventilated patients (ρ = 0.63 to 0.66, all P < 0.01). Conclusions Overall, diaphragm function as assessed with transdiaphragmatic pressure was weakly related to diaphragm thickening fraction. The diaphragm thickening fraction should not be used in healthy subjects or ventilated patients when changes in diaphragm function are evaluated. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

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Role of Bedside Ultrasonography in Assessment of Diaphragm Function as a Predictor of Success of Weaning in Mechanically Ventilated Patients

Tuberculosis and Respiratory Diseases ◽

10.4046/trd.2020.0045 ◽

2020 ◽

Vol 83 (4) ◽

pp. 295-302

Author(s):

Mostafa Ibrahim Elshazly ◽

Khaled Mahmoud kamel ◽

Reem Ibrahim Elkorashy ◽

Mohamed Said Ismail ◽

Jumana Hesham Ismail ◽

...

Keyword(s):

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Diaphragm Function ◽

Predictor Of Success ◽

Bedside Ultrasonography ◽

Ventilated Patients

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Relation of Ultrasound Based Quantitative Indices of Diaphragm Function to the Drive to Breathe in Spontaneously Breathing Mechanically Ventilated Patients

10.1164/ajrccm-conference.2021.203.1_meetingabstracts.a2784 ◽

2021 ◽

Author(s):

V.S.R. Koppurapu ◽

Y. Zemkova ◽

S. Bowmaster ◽

B. Nassar ◽

G.A. Schmidt

Keyword(s):

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Quantitative Indices ◽

Diaphragm Function ◽

Spontaneously Breathing ◽

Ventilated Patients

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Influence of Dexmedetomidine on Diaphragm Function and Postoperative Outcomes in ICU Patients with Mechanical Ventilation

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2021/1990838 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Chengda Zhao ◽

Meihua Huang ◽

Baiyun Wang ◽

Huanhui Zhong ◽

Wen Meng

Keyword(s):

Mechanical Ventilation ◽

Success Rate ◽

Ventilator Weaning ◽

Postoperative Outcomes ◽

Control Group ◽

Diaphragm Thickness ◽

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Diaphragm Function ◽

Ventilated Patients

Objective. To probe into the influence of dexmedetomidine (DEX) on diaphragm function and postoperative outcomes of mechanically ventilated patients in the intensive care unit (ICU). Methods. 84 patients with mechanical ventilation (MV) in the ICU of our hospital were selected as the research participants, including 38 patients in the control group (CG) sedated with midazolam (MZ) and 46 patients in the research group (RG) with DEX sedation. Ramsay sedation score, visual analogue scale (VAS), and restlessness score (RS) were used to evaluate their state before sedation (T0), as well as 2 h (T1), 6 h (T2), and 24 h (T3) after sedation, and the alterations of mean arterial pressure (MAP) and heart rate (HR) were recorded. Serum cortisol (Cor), adrenocorticotropic hormone (ACTH), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin- (IL-) 1β, IL-6, and tumor necrosis factor-α (TNF-α) were measured before and 24 h after sedation. The end-inspiratory diaphragm thickness (DTei) and end-expiratory diaphragm thickness (DTee) were measured within 2 h after the initiation of MV and 5 min after the spontaneous breathing test (SBT), and the diaphragm thickening fraction (DTF) was calculated. Finally, the ventilator weaning, MV time, and the incidence of adverse reactions (ADs) of the two groups were counted. Results. T0 and T3 witnessed no distinct difference in Ramsay, VAS, and RS scores between the two arms ( P > 0.05 ), but at T1 and T2, RG had better sedation state and lower VAS and RS scores than CG ( P < 0.05 ), with more stable vital signs ( P < 0.05 ). After sedation, the contents of oxidative stress and inflammatory factors in RG were lower, while DTee, DTei, and DTF were higher, versus CG ( P < 0.05 ). Moreover, RG presented higher success rate of first ventilator weaning, less MV time, and lower incidence of ADs than CG ( P < 0.05 ). Conclusions. DEX is effective in mechanically ventilated patients in the ICU, which can protect patients against diaphragm function damage, improve the success rate of ventilator weaning, and benefit the postoperative outcome, with excellent and rapid sedation effect and less stress damage to patients.

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