IntroductionAdequate ventilatory support of critically ill patients depends on prompt recognition of ventilator asynchrony, as asynchrony is associated with worse outcomes.We compared an automatic method of patient-ventilator asynchrony monitoring, based on airway flow frequency analysis, to the asynchrony index (AI) determined visually from airway tracings.MethodsThis was a prospective, sequential observational study of 110 mechanically ventilated adults. All eligible ventilated patients were enrolled. No clinical interventions were performed. Airway flow and pressure signals were sampled digitally for two hours. The frequency spectrum of the airway flow signal, processed to include only its expiratory phase, was calculated with the Cooley-Tukey Fast Fourier Transform method at 2.5 minute intervals. The amplitude ratio of the first harmonic peak (H1) to that of zero frequency (DC), or H1/DC, was taken as a measure of spectral organization. AI values were obtained at 30-minute intervals and compared to corresponding measures of H1/DC.ResultsThe frequency spectrum of synchronized patients was characterized by sharply defined peaks spaced at multiples of mean respiratory rate. The spectrum of asynchronous patients was less organized, showing lower and wider H1 peaks and disappearance of higher frequency harmonics. H1/DC was inversely related to AI (n = 110; r2 = 0.57; P < 0.0001). Asynchrony, defined by AI > 10%, was associated H1/DC < 43% with 83% sensitivity and specificity.ConclusionsSpectral analysis of airway flow provides an automatic, non-invasive assessment of ventilator asynchrony at fixed short intervals. This method can be adapted to ventilator systems as a clinical monitor of asynchrony.

Prognostic study, Level II (retrospective study).

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Chronic recurrent multifocal osteomyelitis (CRMO) is a disease of children and young adults. Clinically, the disease is characterized by the insidious onset of local pain and swelling in affected bones. Its course is one of intermittent periods of exacerbation and remission with successive bones affected. The pathogenesis of CRMO remains unknown, although an autoinflammatory disorder may be the cause, with inflammation of bone. This lesion is radiologically characterized as multiple lucencies surrounded by defined zones of patchy but dense sclerosis, cortical thickening from periosteal new bone formation, and increased bone size with different bones involved. Multiple therapeutic regimens had shown only a partial or temporary response. Because indomethacin has been successfully applied in inhibition of ossification and inflammatory processes, we initiated therapy with indomethacin in patients with CRMO. We report on the cases of 5 patients who responded dramatically to treatment with indomethacin. All underwent progressive clinical improvement (mean, 2.8 months). Radiological lesions disappeared after a mean period of 10.5 months. In 1 case where treatment was started late, small osteolytic zones persisted but with no clinical consequences. There were no additional recurrences or new bones affected during follow-up period (mean, 4 years). Our observation indicates that indomethacin may be an effective treatment for CRMO.