title: Standardization of Sonographic Diaphragm Thickness Evaluations in Healthy Volunteers.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Critical Care, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Raúl
authors.initials: R
authors.lastname: Carrillo-Esper
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico. gmemiinv@gmail.com.
authors.forename: Ángel Augusto
authors.initials: ÁA
authors.lastname: Pérez-Calatayud
authors.affiliation: Research in Medical Sciences Neuro-Rehabilitation Laboratory, National Institute of Rehabilitation, Mexico City, Mexico.
authors.forename: Emilio
authors.initials: E
authors.lastname: Arch-Tirado
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Manuel Alejandro
authors.initials: MA
authors.lastname: Díaz-Carrillo
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garrido-Aguirre
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Rafael
authors.initials: R
authors.lastname: Tapia-Velazco
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Peña-Pérez
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Isis
authors.initials: I
authors.lastname: Espinoza-de Los Monteros
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: José Martín
authors.initials: JM
authors.lastname: Meza-Márquez
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Oscar Iván
authors.initials: OI
authors.lastname: Flores-Rivera
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Adriana Denise
authors.initials: AD
authors.lastname: Zepeda-Mendoza
authors.affiliation: Department of Critical Care Medicine, Fundación Clinica Médica Sur, Mexico City 14050, Mexico.
authors.forename: Teresa
authors.initials: T
authors.lastname: de la Torre-León
mesh_terms: D000328:Adult; D015992:Body Mass Index; D016009:Chi-Square Distribution; D003964:Diaphragm / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D045853:Exhalation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D012015:Reference Standards; D012016:Reference Values; D012146:Rest; D014463:Ultrasonography / Q000379:methods / Q000592:standards*; D055815:Young Adult
keywords: diaphragm thickness; ultrasound