BackgroundThe rapid shallow breathing index (RSBI), which is the ratio between respiratory rate (RR) and tidal volume (VT), is one of the most widely used indices to predict weaning outcome. Whereas the diaphragm plays a fundamental role in generating VT, in the case of diaphragmatic dysfunction the inspiratory accessory muscles may contribute. If this occurs during a weaning trial, delayed weaning failure is likely since the accessory muscles are more fatigable than the diaphragm. Hence, we hypothesised that the traditional RSBI could be implemented by substituting VT with the ultrasonographic evaluation of diaphragmatic displacement (DD). We named the new index the diaphragmatic-RSBI (D-RSBI). The aim of this study was to compare the ability of the traditional RSBI and D-RSBI to predict weaning failure in ready-to-wean patients.MethodsWe performed a prospective observational study. During a T-tube spontaneous breathing trial (SBT) we simultaneously evaluated right hemidiaphragm displacement (i.e., DD) by using M-mode ultrasonography as well as the RSBI. Outcome of the weaning attempt, length of mechanical ventilation, length of intensive care unit and hospital stay, and hospital mortality were recorded. Receiver operator characteristic (ROC) curves were used to evaluate the diagnostic accuracy of D-RSBI and RSBI.ResultsWe enrolled 51 patients requiring mechanical ventilation for more than 48 h who were ready to perform a SBT. Most of the patients, 34 (66 %), were successfully weaned from mechanical ventilation. When considering the 17 patients that failed the weaning attempt, 11 (64 %) had to be reconnected to the ventilator during the SBT, three (18 %) had to be re-intubated within 48 h of extubation, and three (18 %) required non-invasive ventilation support within 48 h of extubation. The areas under the ROC curves for D-RSBI and RSBI were 0.89 and 0.72, respectively (P = 0.006).ConclusionsD-RSBI (RR/DD) was more accurate than traditional RSBI (RR/VT) in predicting the weaning outcome.Trial registrationOur clinical trial was retrospectively registered with ClinicalTrials.gov (identifier: NCT02696018). ClinicalTrials.gov processed our record on 25 February 2016.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1479-y) contains supplementary material, which is available to authorized users.
Between 1983 and 1986, the National Institute for Cancer Research in Genoa and affiliated institutions conducted a randomized study to compare two different ways of combining chemotherapy (CT) and radiation therapy (RT). One hundred sixteen patients were randomized to receive neoadjuvant CT followed by definitive RT (treatment arm A) or alternating CT and RT. In treatment arm A, RT consisted of 70 Gy to the involved areas and 50 Gy to the uninvolved neck at 2 Gy/fraction, five fractions per week. In treatment arm B, RT consisted of 60 Gy to involved areas and 50 Gy to the uninvolved neck in three courses of 20 Gy each, 2 Gy/fraction, ten fractions/2 weeks alternated with four courses of CT. CT consisted of vinblastine 6 mg/m2 intravenously followed 6 hours later by bleomycin 30 IU intramuscularly, day 1; methotrexate 200 mg intravenously, day 2; leucovorin rescue, day 3. CT was repeated every 2 weeks up to four courses. The same CT was used in both treatment arms of the study. Fifty-five patients were entered in treatment arm A and 61 in treatment arm B. Complete responses were 7/48 and 19/57 in treatment arms A and B, respectively (P less than 0.03). Four-year progression-free survival was 4% in treatment arm A and 12% in treatment arm B (P less than 0.02), and four-year survival was 10% in A and 22% in B (P less than 0.02). Mucosal tolerance was significantly worse in treatment arm B (P less than 0.00004). The subgroup analysis shows the major improvement of alternating CT and RT in patients with the worst prognostic characteristics.
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