title: Comparison of usual and alternative methods to measure height in mechanically ventilated patients: potential impact on protective ventilation.
abstract: BACKGROUND
  Protective ventilation implementation requires the calculation of predicted body weight (PBW), determined by a formula based on gender and height. Consequently, height inaccuracy may be a limiting factor to correctly set tidal volumes. The objective of this study was to evaluate the accuracy of different methods in measuring heights in mechanically ventilated patients.
  
  
  METHODS
  Before cardiac surgery, actual height was measured with a height gauge while subjects were standing upright (reference method); the height was also estimated by alternative methods based on lower leg and forearm measurements. After cardiac surgery, upon ICU admission, a subject's height was visually estimated by a clinician and then measured with a tape measure while the subject was supine and undergoing mechanical ventilation.
  
  
  RESULTS
  One hundred subjects (75 men, 25 women) were prospectively included. Mean PBW was 61.0 ± 9.7 kg, and mean actual weight was 30.3% higher. In comparison with the reference method, estimating the height visually and using the tape measure were less accurate than both lower leg and forearm measurements. Errors above 10% in calculating the PBW were present in 25 and 40 subjects when the tape measure or visual estimation of height was used in the formula, respectively. With lower leg and forearm measurements, 15 subjects had errors above 10% (P < .001).
  
  
  CONCLUSIONS
  Our results demonstrate that significant variability exists between the different methods used to measure height in bedridden patients on mechanical ventilation. Alternative methods based on lower leg and forearm measurements are potentially interesting solutions to facilitate the accurate application of protective ventilation.
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Bojmehrani
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Maude
authors.initials: M
authors.lastname: Bergeron-Duchesne
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Carmelle
authors.initials: C
authors.lastname: Bouchard
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Serge
authors.initials: S
authors.lastname: Simard
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Bouchard
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Abel
authors.initials: A
authors.lastname: Vanderschuren
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
authors.forename: Erwan
authors.initials: E
authors.lastname: L'Her
authors.affiliation: Centre de Recherche, l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada. francois.lellouche@criucpq.ulaval.ca.
authors.forename: François
authors.initials: F
authors.lastname: Lellouche
mesh_terms: D000367:Age Factors; D000368:Aged; D001510:Bed Rest; D001827:Body Height; D001835:Body Weight; D001837:Body Weights and Measures / Q000379:methods*; D006348:Cardiac Surgical Procedures; D005260:Female; D005542:Forearm; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D012737:Sex Factors; D016683:Supine Position; D013990:Tidal Volume
keywords: acute lung injury; height; measure; predicted body weight; protective mechanical ventilation; tidal volume; ventilator-induced lung injury