title: Comparison and effects of two different airway occlusion times during measurement of maximal inspiratory pressure in adult intensive care unit neurological patients.
abstract: OBJECTIVE
  To verify if the maximal inspiratory pressure values with 40 seconds occlusion time are greater than with the 20 seconds occlusion time, and the impacts on the following patient's physiological variables: respiratory rate, pulse oxygen saturation, heart rate and blood pressure, before and after the measurements.
  
  
  METHODS
  This was a transversal prospective randomized study. Fifty-one patients underwent maximal inspiratory pressure measurement, measured by one single investigator. The manometer was calibrated before each measurement, and then connected to the adapter and this to the unidirectional valve inspiratory branch for 20 or 40 seconds.
  
  
  RESULTS
  The values with 40 seconds occlusion (57.6 ± 23.4 cmH2O) were significantly higher than the measurements taken with 20 seconds occlusion (40.5 ± 23.4 cmH2O; p=0.0001). The variables changes between the before and after measurement respiratory and hemodynamic parameters monitoring showed: heart rate variation for the 20 seconds occlusion 5.13 ± 8.56 beats per minute and after 40 seconds occlusion 7.94 ± 12.05 beats per minute (p = 0.053), versus baseline. The mean blood pressure change for 20 seconds occlusion was 9.29 ± 13.35 mmHg and for 40 seconds occlusion 15.52 ± 2.91 mmHg (p=0.021). The oxygen saturation change for 20 seconds occlusion was 1.66 ± 12.66%, and for 40 seconds 4.21 ± 5.53% (p=0.0001). The respiratory rate change for 20 seconds occlusion was 6.68 ± 12.66 movements per minute and for 40 seconds 6.94 ± 6.01 (p=0.883).
  
  
  CONCLUSIONS
  The measurement of maximal inspiratory pressure using a longer occlusion (40 seconds) produced higher values, without triggering clinically significant stress according to the selected variables.
authors.affiliation: Curso de Fisioterapia em UTI, Universidade Federal da Bahia - UFBA, Salvador, BA, Brasil.
authors.forename: Gilvan Reis
authors.initials: GR
authors.lastname: Pinheiro Filho
authors.affiliation: Escola Bahiana de Medicina e Saúde Pública, Salvador, BA, Brasil.
authors.forename: Helena França Correia Dos
authors.initials: HF
authors.lastname: Reis
authors.affiliation: Hospital Geral do Estado, Salvador, BA, Brasil.
authors.forename: Mônica Lajana de
authors.initials: ML
authors.lastname: Almeida
authors.affiliation: Hospital Geral do Estado - HGE, Salvador, BA, Brasil.
authors.forename: Wandalvo de Souza
authors.initials: Wde S
authors.lastname: Andrade
authors.affiliation: Universidade Federal da Bahia - UFBA, Salvador, BA, Brasil.
authors.forename: Rodolfo Leal Sampaio
authors.initials: RL
authors.lastname: Rocha
authors.affiliation: Hospital Geral do Estado, Salvador, BA, Brasil.
authors.forename: Petrônio Andrade
authors.initials: PA
authors.lastname: Leite