Impacto de um protocolo de desmame de ventilação mecânica na taxa de falha de extubação em pacientes de difícil desmame / Impact of a mechanical ventilation weaning protocol on the extubation failure rate in difficult-to-wean patients

OBJETIVO: Determinar se a acurácia preditiva do julgamento clínico isolado pode ser melhorada com o uso suplementar de um protocolo de desmame objetivo como ferramenta de suporte para a tomada de decisão. MÉTODOS: Estudo prospectivo multicêntrico de coorte realizado em três UTIs clínicas/cirúrgicas. Foram incluídos no estudo todos os pacientes de difícil desmame (falha no primeiro teste de ventilação espontânea [TVE]), sob ventilação mecânica (VM) por mais de 48 h, admitidos em uma das UTIs entre janeiro de 2002 e dezembro de 2005. Os pacientes do grupo protocolo (GP) foram extubados após teste de tubo T de acordo com um protocolo de desmame e comparados com o grupo de pacientes extubados sem o uso do protocolo (GNP). O desfecho primário foi a taxa de reintubação em até 48 h após a extubação. RESULTADOS: Foram incluídos 731 pacientes - 533 (72,9%) no GP e 198 (27,1%) no GNP. A taxa global de reintubação foi de 17,9%. As taxas de sucesso da extubação no GP e no GNP foram 86,7% e 69,6%, respectivamente (p < 0,001). Não houve diferenças significativas entre os grupos quanto a idade, gênero, escore de gravidade e tempo de VM antes da inclusão. Entretanto, DPOC foi mais frequente no GNP que no GP (44,4% vs. 17,6%; p < 0,001), ao passo que pacientes sépticos e em pós-operatório foram mais comuns no GP (23,8% vs. 11,6% e 42,4% vs. 26,4%, respectivamente; p < 0,001 para ambos). O tempo de VM após a falha no primeiro TVE foi maior no GP que no GNP (9 ± 5 dias vs. 7 ± 2 dias; p < 0,001). CONCLUSÕES: Nesta amostra de pacientes de difícil desmame, o uso de um protocolo de desmame melhorou o processo decisório, reduzindo a possibilidade de falha na extubação.

OBJECTIVE: To determine whether the predictive accuracy of clinical judgment alone can be improved by supplementing it with an objective weaning protocol as a decision support tool. METHODS: This was a multicenter prospective cohort study carried out at three medical/surgical ICUs. The study involved all consecutive difficult-to-wean ICU patients (failure in the first spontaneous breathing trial [SBT]), on mechanical ventilation (MV) for more than 48 h, admitted between January of 2002 and December of 2005. The patients in the protocol group (PG) were extubated after a T-piece weaning trial and were compared with patients who were otherwise extubated (non-protocol group, NPG). The primary outcome measure was reintubation within 48 h after extubation. RESULTS: We included 731 patients-533 (72.9%) and 198 (27.1%) in the PG and NPG, respectively. The overall reintubation rate was 17.9%. The extubation success rates in the PG and NPG were 86.7% and 69.6%, respectively (p < 0.001). There were no significant differences between the groups in terms of age, gender, severity score, or pre-inclusion time on MV. However, COPD was more common in the NPG than in the PG (44.4% vs. 17.6%; p < 0.001), whereas sepsis and being a post-operative patient were more common in the PG (23.8% vs. 11.6% and 42.4% vs. 26.4%, respectively; p < 0.001 for both). The time on MV after the failure in the first SBT was higher in the PG than in the NPG (9 ± 5 days vs. 7 ± 2 days; p < 0.001). CONCLUSIONS: In this sample of difficult-to-wean patients, the use of a weaning protocol improved the decision-making process, decreasing the possibility of extubation failure.

Cirrose experimental induzida pela inalaçao de tetracloreto de carbono: adaptaçao da técnica e avaliaçao da peroxidaçao lipídica / Experimental cirrhosis induced by carbon tetrachloride inhalation: adaptation of the technique and evaluation of lipid peroxidation

BACKGROUND: Long-term administration of carbon tetrachloride is an accepted experimental model to produce hepatic fibrosis. Oxidative stress has been postulated as a major molecular mechanism involved in carbon tetrachloride hepatotoxicity, where the reactive oxygen species play an important role in the pathogenesis of liver fibrosis. AIMS: This study was conducted to evaluate the effectiveness of an experimental model of hepatic cirrhosis induced by carbon tetrachloride inhalation as well as the importance of lipid peroxidation and the characteristics of the ascitic fluid in this model. METHODS: At first the hepatic histologic findings were assessed using the hematoxilineosin technique in different moments of carbon tetrachloride inhalation (5th, 7th, 9th, 12th weeks). Later, at the end of 15 weeks of the study the rats were divided in three groups (control; control + phenobarbital; and carbon tetrachloride + phenobarbital) for lipid peroxidation, ascitic fluid and histologic characteristics evaluation. For the lipid peroxidation analysis, thiobarbituric acid and QL techniques were used. Cytologic and bacteriologic parameters were analysed in the ascitic fluid. RESULTS: Cirrhosis was established in 100 per cent of carbon tetrachloride rats between the 12th and 15th weeks with an elevation in the lipid peroxidation carbon tetrachloride rats' livers. Ascitic fluid infection was observed in one of seven rats who has developed ascites. CONCLUSIONS: The carbon tetrachloride inhalation method developed in this study is effective in cirrhosis induction and ascites formation, and the carbon tetrachloride cirrhosis physiopathogenesis is probably related to the oxidative stress installation.