Avaliação da força muscular inspiratória (PImáx) durante o desmame da ventilação mecânica em pacientes neurológicos internados na unidade de terapia intensiva / Evaluation of inspiratory muscular force (Plmax) during weaning from mechanical ventilation in neurological patients in the intensive care unit

A ventilação mecânica, freqüentemente necessária em pacientes em estado crítico, pode ser associada à perda de força muscular respiratória por diversos mecanismos. Nosso objetivo foi avaliar a progressão da força da musculatura respiratória durante o processo de desmame, por mensuração seriada da PImáx até a independência completa da ventilação mecânica em pacientes neurológicos. A PImáx foi avaliada evolutivamente, uma vez ao dia, durante todo o período de desmame, com auxílio de manovacuômetro e válvula unidirecional. Foram incluídos no estudo 31 pacientes neurológicos (pós acidente vascular ou trauma crânio-encefálico) em desmame ventilatório e os valores obtidos foram comparados aos previstos, segundo Black e Hyatt15. A média de PImáx inicial (primeiro dia do desmame) foi - 40,0±20,0 cmH2O (39% do previsto) (p < 0, 05); 50% no 5º e 60% no 10º dia de desmame. Houve um aumento de 21% (p < 0,05) do 1º ao 10º dia. Todos os pacientes foram completamente retirados da ventilação mecânica até o 13º dia de desmame. Sendo assim, a evolução ascendente da força muscular inspiratória, em pacientes em ventilação mecânica prolongada, demonstra que a independência completa do ventilador, em pacientes neurológicos, é possível a partir de 72% dos valores previstos.

Mechanical ventilation, often needed in critically ill patients, may be associated to loss of respiratory muscular force due to several mechanisms. The objective was to assess the progression of respiratory muscular force during weaning from mechanical ventilation by using serial measurement of maximum inspiratory pressure until complete discontinuation in neurological patients. The PImax was progressively assessed by using manovacuometer and unidirectional valve once a day during the whole period of mechanical ventilation weaning. Thirty-one neurological patients (after stroke or craniocerebral trauma) undergoing weaning from mechanical ventilation were included for study, and the values obtained were compared to those established by Black and Hyatt15. The initial mean PImax (first day of weaning) was - 40.0±20.0 cmH2O (39% of the expected value) (p < 0.05), reaching 50% at day 5 and 60% at day 10. It was observed an increase of 21% (p < 0.05) between the first and tenth days. On the 13th day, mechanical ventilation had been completely discontinued in all patients. Therefore a progressive evaluation of the inspiratory muscular force in patients undergoing prolonged mechanical ventilation shows that the complete discontinuation is possible in neurological patients with 72% of the established values.

Adhesiveness and purulence of respiratory secretions: implications for mucociliary transport in patients with bronchiectasis.

OBJECTIVE: To analyze and compare the transport properties of respiratory secretions, classified by selected parameters, in individuals with bronchiectasis unrelated to cystic fibrosis. METHODS: We collected mucus samples from 35 individuals with bronchiectasis unrelated to cystic fibrosis. The samples were first classified by their surface properties (adhesive or nonadhesive), as well as by their aspect (mucoid or purulent). We then tested the samples regarding relative transport velocity (RTV), displacement in a simulated cough machine (SCM), and contact angle (CA). For the proposed comparisons, we used ANOVA models, with a level of significance set at 5%. RESULTS: In comparison with nonadhesive samples, adhesive samples showed significantly less displacement in the SCM, as well as a significantly higher CA (6.52 ± 1.88 cm vs. 8.93 ± 2.81 cm and 27.08 ± 6.13º vs. 22.53 ± 5.92º, respectively; p < 0.05 for both). The same was true in the comparison between purulent and mucoid samples (7.57 ± 0.22 cm vs. 9.04 ± 2.48 cm and 25.61 ± 6.12º vs. 21.71 ± 5.89º; p < 0.05 for both). There were no significant differences in RTV among the groups of samples, although the values were low regardless of the surface properties (adhesive: 0.81 ± 0.20; nonadhesive: 0.68 ± 0.24) or the aspect (purulent: 0.74 ± 0.22; mucoid: CONCLUSIONS: The respiratory secretions of patients with bronchiectasis showed decreased mucociliary transport. Increased adhesiveness and purulence cause the worsening of transport properties, as demonstrated by the lesser displacement in the SCM and the higher CA.

Adesividade e purulência de secreções respiratórias: implicações no transporte mucociliar em pacientes com bronquiectasias / Adhesiveness and purulence of respiratory secretions: implications for mucociliary transport in patients with bronchiectasis

OBJETIVO: Analisar e comparar as propriedades de transporte de secreções respiratórias, classificadas através de parâmetros selecionados, de indivíduos com bronquiectasias não secundárias à fibrose cística. MÉTODOS: Foram avaliadas amostras de muco respiratório, classificadas como com propriedades de superfície adesivas ou não adesivas, assim como com aspecto mucoide ou purulento, de 35 participantes com bronquiectasias não secundárias à fibrose cística, quanto a velocidade relativa de transporte (VRT), deslocamento em máquina simuladora de tosse (MST) e ângulo de contato (AC). Para as comparações propostas, foram utilizados modelos de ANOVA, com nível de significância estabelecido em 5 por cento. RESULTADOS: Houve uma diminuição significativa no deslocamento em MST, assim como um aumento significativo no AC, das amostras adesivas quando comparadas às não adesivas (6,52 ± 1,88 cm vs. 8,93 ± 2,81 cm e 27,08 ± 6,13º vs. 22,53 ± 5,92º, respectivamente; p < 0,05 para ambos). O mesmo ocorreu na comparação entre as amostras purulentas e mucoides (7,57 ± 0,22 cm vs. 9,04 ± 2,48 cm e 25,61 ± 6,12º vs. 21,71 ± 5,89º; p < 0,05 para ambos). Não houve diferença na VRT entre os grupos, embora os valores estivessem diminuídos, independentemente da adesividade (adesivas: 0,81 ± 0,20; não adesivas: 0,68 ± 0,24) ou do aspecto (purulentas: 0,74 ± 0,22; mucoides: 0,82 ± 0,22) das amostras. CONCLUSÕES: A secreção respiratória de pacientes com bronquiectasia apresentou uma diminuição do transporte ciliar. Maior adesividade e purulência favorecem a piora das propriedades de transporte, demonstradas pela diminuição do deslocamento em MST e pelo aumento do AC.

OBJECTIVE: To analyze and compare the transport properties of respiratory secretions, classified by selected parameters, in individuals with bronchiectasis unrelated to cystic fibrosis. METHODS: We collected mucus samples from 35 individuals with bronchiectasis unrelated to cystic fibrosis. The samples were first classified by their surface properties (adhesive or nonadhesive), as well as by their aspect (mucoid or purulent). We then tested the samples regarding relative transport velocity (RTV), displacement in a simulated cough machine (SCM), and contact angle (CA). For the proposed comparisons, we used ANOVA models, with a level of significance set at 5 percent. RESULTS: In comparison with nonadhesive samples, adhesive samples showed significantly less displacement in the SCM, as well as a significantly higher CA (6.52 ± 1.88 cm vs. 8.93 ± 2.81 cm and 27.08 ± 6.13º vs. 22.53 ± 5.92º, respectively; p < 0.05 for both). The same was true in the comparison between purulent and mucoid samples (7.57 ± 0.22 cm vs. 9.04 ± 2.48 cm and 25.61 ± 6.12º vs. 21.71 ± 5.89º; p < 0.05 for both). There were no significant differences in RTV among the groups of samples, although the values were low regardless of the surface properties (adhesive: 0.81 ± 0.20; nonadhesive: 0.68 ± 0.24) or the aspect (purulent: 0.74 ± 0.22; mucoid: CONCLUSIONS: The respiratory secretions of patients with bronchiectasis showed decreased mucociliary transport. Increased adhesiveness and purulence cause the worsening of transport properties, as demonstrated by the lesser displacement in the SCM and the higher CA.