Avaliação da pressão inspiratória máxima em pacientes críticos não-cooperativos: comparação entre dois métodos

Abstract

Background: Although mechanical ventilation is necessary for treating acute respiratory insufficiency, it may be associated with deconditioning and respiratory muscle dysfunction. Maximal inspiratory pressure (MIP) evaluation is used to estimate inspiratory muscle strength in artificially ventilated patients, but there is no definition as to the best way to make this measurement. Objective: To compare two methods for MIP evaluation, using four different protocols, among non-cooperative artificially ventilated patients. Method: Thirty non-cooperative patients undergoing the process of weaning off mechanical ventilation were evaluated. In accordance with block randomization, the simple occlusion method (OM) or the unidirectional valve method (UV) was applied to each patient for time periods of 20 and 40 seconds. Additionally, during the 40s measurements, the MIP value at 30s was recorded. Results: The MIP values were higher at 40s than at 20s, both from OM (48.2 ± 21.7 vs. 36 ± 18.7 cmH 2 O; p< 0.001) and from UV (56.6 ± 23.3 vs. 43.4 ± 24 cmH 2 O; p< 0.001). The MaxIP values were higher from UV at 40s (UV40) than from OM at 40s (OM40) (56.6 ± 23.3 vs. 48.2 ± 21.7 cmH 2 O; p< 0.001). There was a difference between UV at 30 and 40s (51.5 ± 20.8 vs. 56.6 ± 23.3 cmH 2 O; p< 0.001). Conclusion: Among non-cooperative patients, higher MIP values were obtained from the unidirectional valve method with 40s of occlusion than from the other protocols evaluated.

Análise da força muscular expiratória e respiração espontânea de indivíduos em ventilação mecânica: estudo transversal

“…Measurements of respiratory pressures lasted from 40 to 60 seconds, having as subjective basis the patients' comfort (adapted from Guimarães et al 22 ) and were only repeated if deemed necessary. On MEP, a manovacuometer (Comercial Médica -SP/Brazil, ±120 cmH 2 O) with oneway valve that allowed only the inspiration necessary for the Valsalva maneuver was attached to the AAW: maximal expiratory effort in total lung capacity (TLC) with occlusive AAW.…”

Comparação e efeitos de dois diferentes tempos de oclusão da via aérea durante a mensuração da pressão inspiratória máxima em pacientes neurológicos na unidade de terapia intensiva de pacientes adultos

“…The measurement was performed by one single investigator, with the manometer calibrated before each measurement keeping the pointer on zero, and next connected to the adapter and this to the unidirectional valve inspiratory branch. (14) The randomization was made by simple lottery, according to which was decided the initial airway occlusion time used for the subjects entering the trial. This random order of the initial times had a 15 minutes interval.…”

“…A recent trial investigated the IPmax evaluation in thirty non-cooperative and under MV weaning patients using two occlusion times, 20 and 40 seconds, showing significant differences for the IP40 versus IP20 comparison (56.6 ± 23.3 versus 43.4 ± 24 cmH2O; p<0.001), agreeing with this trial results, reporting as the best IPmax evaluation for non-cooperative patients a 40 seconds occlusion. (14) Another trial evaluated two occlusion methods in a heterogeneous 28 subjects population, either with or without consciousness level changes, under ventilatory weaning process, concluding that IP20 looks to be insufficient to measure the real IPmax in GCSS < 15 patients. (3) However, the measurement should have been performed in a more homogeneous patients population, such as in traumatic and non-traumatic, clinical and surgical neurological patients.…”

“…A recent trial mentioned that patients were monitored regarding HR and SpO2, however pre-and post-measurement values were not recorded, rendering impossible to evaluate prolonged maneuver impacts, particularly at 40 seconds. (14) The risks for this technique use include increased RR, HR and BP, and decreased SpO2, however, among the benefits can be mentioned being able to predict possible MV discontinuation failure and obtaining a parameter for muscle strength loss and gain in respiratory training subjects.…”

Equações preditivas e valores de normalidade para pressões respiratórias máximas na infância e adolescência

“…A mensuração da força muscular respiratória permite identificar precocemente quadros de fraqueza muscular respiratória e de insuficiência respiratória (1) , proporciona maior segurança no tratamento de pacientes (2) , indica a gravidade, as consequências funcionais e o progresso de diversas disfunções pulmonares e neuromusculares (3) , além de contribuir para um melhor acompanhamento do processo de desmame da ventilação mecânica (4) . Existem diversos procedimentos invasivos ou não para avaliar a força muscular respiratória.…”