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Abstract
Reversibility and impact of diaphragmatic dysfunction (DD) are unknown. The principal
aim was to describe diaphragmatic function as assessed by ultrasonography during weaning
trials.
Although diaphragmatic motion is readily studied by ultrasonography, the procedure remains poorly codified. The aim of this prospective study was to determine the reference values for diaphragmatic motion as recorded by M-mode ultrasonography. Two hundred ten healthy adult subjects (150 men, 60 women) were investigated. Both sides of the posterior diaphragm were identified, and M-mode was used to display the movement of the anatomical structures. Examinations were performed during quiet breathing, voluntary sniffing, and deep breathing. Diaphragmatic excursions were measured from the M-mode sonographic images. In addition, the reproducibility (inter- and intra-observer) was assessed. Right and left diaphragmatic motions were successfully assessed during quiet breathing in all subjects. During voluntary sniffing, the measurement was always possible on the right side, and in 208 of 210 volunteers, on the left side. During deep breathing, an obscuration of the diaphragm by the descending lung was noted in subjects with marked diaphragmatic excursion. Consequently, right diaphragmatic excursion could be measured in 195 of 210 subjects, and left diaphragmatic excursion in only 45 subjects. Finally, normal values of both diaphragmatic excursions were determined. Since the excursions were larger in men than in women, the gender should be taken into account. The lower limit values were close to 0.9 cm for women and 1 cm for men during quiet breathing, 1.6 cm for women and 1.8 cm for men during voluntary sniffing, and 3.7 cm for women and 4.7 cm for men during deep breathing. We demonstrated that M-mode ultrasonography is a reproducible method for assessing hemidiaphragmatic movement.
To determine the prevalence of diaphragmatic dysfunction diagnosed by M-mode ultrasonography (vertical excursion <10 mm or paradoxic movements) in medical intensive care unit patients and to assess the influence of diaphragmatic dysfunction on weaning outcome. Prospective, observational study. Twenty-eight-bed medical intensive care unit in a university-affiliated hospital. Eighty-eight consecutive patients in the medical intensive care unit who required mechanical ventilation over 48 hrs and met the criteria for a spontaneous breathing trial were assessed. Patients with a history of diaphragmatic or neuromuscular disease or evidence of pneumothorax or pneumomediastinum were excluded. During spontaneous breathing trial, each hemidiaphragm was evaluated by M-mode ultrasonography using the liver and spleen as windows with the patient supine. Rapid shallow breathing index was simultaneously calculated at the bedside. The prevalence of ultrasonographic diaphragmatic dysfunction among the eligible 82 patients was 29% (n = 24). Patients with diaphragmatic dysfunction had longer weaning time (401 [range, 226-612] hrs vs. 90 [range, 24-309] hrs, p < .01) and total ventilation time (576 [range, 374-850] hrs vs. 203 [range, 109-408] hrs, p < .01) than patients without diaphragmatic dysfunction. Patients with diaphragmatic dysfunction also had higher rates of primary (20 of 24 vs. 34 of 58, p < .01) and secondary (ten of 20 vs. ten of 46, p = .01) weaning failures than patients without diaphragmatic dysfunction. The area under the receiver operating characteristics curve of ultrasonographic criteria in predicting weaning failure was similar to that of rapid shallow breathing index. Using M-mode ultrasonography, diaphragmatic dysfunction was found in a substantial number of medical intensive care unit patients without histories of diaphragmatic disease. Patients with such diaphragmatic dysfunction showed frequent early and delayed weaning failures. Ultrasonography of the diaphragm may be useful in identifying patients at high risk of difficulty weaning.
The use of ultrasonography has become increasingly popular in the everyday management of critically ill patients. It has been demonstrated to be a safe and handy bedside tool that allows rapid hemodynamic assessment and visualization of the thoracic, abdominal and major vessels structures. More recently, M-mode ultrasonography has been used in the assessment of diaphragm kinetics. Ultrasounds provide a simple, non-invasive method of quantifying diaphragmatic movement in a variety of normal and pathological conditions. Ultrasonography can assess the characteristics of diaphragmatic movement such as amplitude, force and velocity of contraction, special patterns of motion and changes in diaphragmatic thickness during inspiration. These sonographic diaphragmatic parameters can provide valuable information in the assessment and follow up of patients with diaphragmatic weakness or paralysis, in terms of patient-ventilator interactions during controlled or assisted modalities of mechanical ventilation, and can potentially help to understand post-operative pulmonary dysfunction or weaning failure from mechanical ventilation. This article reviews the technique and the clinical applications of ultrasonography in the evaluation of diaphragmatic function in ICU patients.
[1
]
Service de réanimation polyvalente, Versailles-Le Chesnay, France luciefenet84@gmail.com.
[2
]
Service de réanimation polyvalente, Versailles-Le Chesnay, France.
[3
]
Réanimation Médicale et Médicine Hyperbare, Centre Hospitalier Universitaire Angers,
Faculté de Médecine, Université d'Angers, Angers, France.
[4
]
SAMU 78 SMUR de Versailles, Le Chesnay, France.
[5
]
Service de réanimation polyvalente, Versailles-Le Chesnay, France Service de pneumologie
et de soins intensifs, Hôpital Européen Georges Pompidou-20 rue Leblanc, 75015 Paris,
France.
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