RT Journal Article
SR Electronic
T1 How much time is necessary to assess maximal inspiratory pressure by unidirectional expiratory valve method in subjects without artificial airway?
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P4302
VO 44
IS Suppl 58
A1 Samantha Grams
A1 Karen Kimoto
A1 Elen Azevedo
A1 Christina Brito
A1 Wellington Yamaguti
YR 2014
UL http://erj.ersjournals.com/content/44/Suppl_58/P4302.abstract
AB The most used method to evaluate maximal inspiratory pressure is by maintaining maximum negative pressure forced against an occluded airway (MIPsta). To overcome the need for collaboration during MIPsta, a new technique was developed using a unidirectional expiratory valve in patients undergoing invasive mechanical ventilation (MIPuni). For this evaluation, the occlusion should be maintained for at least 20 seconds to record maximal pressure. Recently, MIPuni has also been performed in subjects under spontaneous breathing without artificial airway. However, the necessary time to obtain MIPuni in subjects without artificial airway is still unknown. The aim of this study was to determine how much time is necessary to obtain MIPuni in subjects without artificial airway. Thirty-one subjects performed both MIPsta and MIPuni methods. For MIPuni, a digital vacuum manometer was attached to a unidirectional expiratory valve and a face mask for 20 seconds. During this period, all subjects were encouraged to make maximal respiratory efforts. To define the optimum duration of the maneuver, the 20 seconds of observation were partitioned every five-second interval (0-5s, 0-10s, 0-15s, 0-20s). MIPuni (117.3 ± 24.8 cmH2O; p<0.001) presented a statistically significant difference when compared to MIPsta (102.5 ± 23.9 cmH2O). Maximal peak values for MIPuni were achieved within the 20-second time window, which differed significantly from the peak values obtained during the 0-5s interval (p=0.036). We recommend that the occlusion should be maintained for at least 20 seconds to record MIPuni in subjects without artificial airway.