Diaphragmatic Ultrasonography, a Novel Approach in Critical Care: A Proposal for a New Weaning Index.

The evaluation of the diaphragm in critically ill patients is simple and noninvasive and has shown good repeatability. The aim of the study was to generate a predictive index for successful weaning (ULDIMex) from invasive mechanical ventilation (IMV) based on an ultrasonographic diaphragmatic assessment before performing a spontaneous breathing test. We recruited patients who required IMV and who were candidates for weaning from ventilation. The measurement of diaphragmatic excursion and time during inspiration and expiration was obtained with a 3- to 5-MHz probe in the M mode. Using the formula (a + b)c/2, the value for the ULDIMex was obtained to evaluate its impact on predicting the successful weaning of IMV, where a is the time during the inspiratory phase, b is the time during expiration, and c is the diaphragmatic excursion during the inspiratory phase, which corresponds to the highest point of the curve from the baseline. We recruited 114 patients, of whom 86 (76%) were successfully weaned from IMV. The patients who were successfully weaned from the IMV had a cutoff value greater than 4.06 cm/s for the ULDIMex index, with a sensitivity of 92.8% (95% confidence interval, 76.5-99.1), specificity of 63.9% (95% confidence interval, 52.9-74.0), positive predictive value of 45.6%, and negative predictive value of 96.5%. The ULDIMex index demonstrated a good level of discrimination for successful weaning prediction. Considering the excellent negative likelihood ratio of the ULDIMex index of greater than 4.06, this index may be considered before performing an spontaneous breathing test to identify critically ill adult patients who will extubate successfully.

Pulmonary Ultrasound: A New Era in Critical Care Medicine.

Pulmonary ultrasonography is a complementary study that is easy to perform at the patient bedside with no need to transfer the patient to special areas. The technique provides information with high sensitivity and specificity for different pathologies. Pulmonary ultrasonography is a very important diagnostic tool in the assessment of lung, pleural, and chest wall diseases. Pulmonary ultrasound provides low-cost analysis, easy real-time reproduction, and safety, all of which have made it a beneficial tool in the diagnostic arsenal available to medical personnel. The purpose of this review was to describe the usefulness of pulmonary ultrasound in critical areas.

Standardization of Sonographic Diaphragm Thickness Evaluations in Healthy Volunteers.

BACKGROUND: B-mode ultrasound can be used to measure diaphragm thickness at the zone of apposition. We believe it is necessary to develop normal values for diaphragm thickness at rest in a large group of healthy subjects and compare them with international results. METHODS: Ultrasound measurements of diaphragm thickness at expiratory rest were taken in 109 healthy individuals, with results stratified by sex, body mass index, and thorax circumference. The following methods were used for analysis and interpretation. Multivariable databases with descriptive statistical analyses were made. The Pearson chi-square test was used to evaluate the distribution between variables. Additionally, mean and SD values were calculated. For standardization, the data were separated by sex within a 95% CI, and we calculated a Z test. A 95% CI was also constructed for proportion analyses. RESULTS: One hundred nine healthy volunteers were included in the study, and the correlation between the body mass index and thorax circumference values with a Pearson chi-square test resulted in an r = 0.69. Additionally, the average value of diaphragmatic thickness was 0.19 ± 0.04 cm (95% CI 0.17-0.20 cm) for men and 0.14 ± 0.03 cm (95% CI 0.13-0.15 cm) for women (P = .001). There was no relation between body mass index thorax circumference, and diaphragmatic thickness. CONCLUSION: Real-time ultrasound of the diaphragm is a simple, inexpensive, and portable imaging technique that can provide qualitative anatomical information. The findings in this study show that sonographic diaphragm evaluations can be applied to the general population.