The 10 Hz dynamic response of a fluid-filled pressure monitoring system is a novel alternative to the fast flush test and indicative of unacceptable systolic pressure overshoot.

The standard method for qualitatively evaluating the dynamic response is to see if the gain of the amplitude spectrum curve approaches 1 (input signal = output signal) over the frequency band of the blood pressure waveform. In a previous report, Watanabe reported that Gardner's natural frequency and damping coefficient, which are widely used as evaluation methods, do not reflect the dynamic response of the circuit. Therefore, new parameters for evaluating the dynamic response of pressure monitoring circuits were desired. In this study, arterial pressure catheters with length of 30, 60, 150, and 210 cm were prepared, and a blood pressure wave calibrator, two pressure monitors with analog output and a personal computer were used to analyze blood pressure monitoring circuits. All data collection and analytical processes were performed using step response analysis program. The gain at 10 Hz was close to 1 and the systolic blood pressure difference was small in the short circuits (30 cm, 60 cm), and the gain at 10 Hz was 1.3-1.5 in the 150 cm circuit and over 1.7 in the 210 cm circuit. The difference in systolic blood pressure increased in proportion to the length of the circuit. It could also be inferred that the gain at 10 Hz should be less than 1.2 to meet a clinically acceptable blood pressure difference. In conclusion, the gain at 10 Hz is sufficiently useful as an indicator to determine the correct systolic blood pressure.

Why the natural frequency and the damping coefficient do not evaluate the dynamic response of clinically used pressure monitoring circuits correctly.

PURPOSE: The dynamic response of pressure monitoring circuits must be evaluated to obtain true invasive blood pressure values. Since Gardner's recommendations in 1981, the natural frequency and the damping coefficient have become standard parameters for anesthesiologists. In 2006, we published a new dynamic response evaluation method (step response analysis) that can plot frequency spectrum curves instantly in clinical situations. We also described the possibility of the defect of the standard parameters. However, the natural frequency and the damping coefficient are considered the gold standard and are even included in a major anesthesiology textbook. Therefore, we attempted to clarify the issues of these parameters with easy-to-understand pressure waves and basic numerical formulae. METHODS: A blood pressure wave calibrator, a single two-channel pressure amplifier, and personal computer were used to analyze blood pressure monitoring circuits. All data collection and analytical processes were performed using our step response analysis program. RESULTS: We compared two different circuits with almost the same natural frequency and damping coefficients. However, their amplitude spectrum curves and input/output pressure values were significantly different. CONCLUSIONS: The natural frequency and the damping coefficient are inadequate for the dynamic response evaluation. These parameters are primarily obtained from the phase spectrum curve and not from the amplitude spectrum curve. We strongly recommend an evaluation using the amplitude spectrum curve with our step response analysis method. It is crucial to maintain an amplitude gain of 1 (input amplitude = output amplitude) in the pressure wave frequency range of 0-20 Hz.

Rosai-Dorfman disease presenting as a solitary mediastinal mass.

Rosai-Dorfman disease (RDD) involving an extranodal site is a diagnostic challenge. Reported herein is the case of a 67-year-old man who presented with a solitary superior mediastinal mass. The lesion was clinically suspected of malignancy including lymphoma because of its high uptake during a (67)Ga-scintigram and (18)F-fluorodeoxyglucose-positron emission tomography. There was no evidence of spread of the disease. Histology of thoracoscopic biopsy specimens indicated granulomatous lesion with infiltration of lymphocytes, plasma cells, and histiocytes with lymphocytes engulfed in their cytoplasm. The lesion did not contain lymph node or thymic elements. On immunohistochemistry the histiocytes were positive for S-100 protein, CD68, and CD163 but were negative for CD1a. These findings suggested a diagnosis of RDD. Despite lack of intervention, the lesion remained almost the same size for 3 years. To the best of the authors' knowledge this is the first case of RDD presenting as a solitary mediastinal mass.

An asymptomatic case of pulmonary cryptococcosis with endobronchial polypoid lesions and bilateral infiltrative shadow.

A case of pulmonary cryptococcosis with focal endobronchial polypoid lesions is described. A 64-year-old woman consulted our hospital for further evaluation of an abnormal shadow on a chest radiograph. She had been prescribed corticosteroid for rheumatoid arthritis. Chest radiographs revealed an infiltrative shadow in the right lower and left middle and lower lung fields, and chest computed tomography (CT) revealed bilateral airspace consolidations and multiple nodules. A bronchoscopic finding revealed white polypoid lesions at the orifice of the posterior basal bronchus in the left lower lobe. Histopathological examination of transbronchial biopsy specimens demonstrated cryptococcal organisms. After fluconazole therapy for 4 months, the infiltrate had decreased in size and the bronchial polypoid lesions had disappeared.

[Asthma control test (ACT) faultiness and the remediation by peak flow (PEF) measurement at outpatient department].

BACKGROUND: To grasp the asthma patients' control level, an asthma control test (ACT), an easy questionnaire, is getting to be used as the alternative method of asthma diary recording. ACT is based on the patient's 4-week memory and the accuracy is not confirmed thoroughly METHODS: Two hundred and eighty three visits of 88 asthmatics (male 29, female 59) were subjected. The accuracy of ACT to detect "truly good control" was analyzed by comparing with the asthma diary (symptoms and PEF were recorded). RESULTS: Sensitivities, specificities (chi square values) for extraction of truly good control were 0.88, 0.42 (23.7) by the threshold of ACT > or =23, 0.77, 0.51 (18.1) by ACT > or =24, and 0.54, 0.69 (12.9) by ACT=25, significantly (p<0.001, respectively). When PEF% predicted > or =80% was added as the second factor, the chi square values improved to 29.9 by ACT > or =23 and to 30.3 by ACT > or =24 significantly (p<0.001, respectively). CONCLUSION: Addition of PEF measurement on visit on ACT may help understanding the asthmatic patient condition.

Pulmonary mucormycosis (Cunninghamella bertholletiae) with cavitation diagnosed using ultra-thin fibre-optic bronchoscopy.

Recently, ultra-thin bronchoscopy has made it possible to observe smaller bronchi not visualized using standard techniques. We describe a case of pulmonary mucormycosis with cavitation, diagnosed using an ultra-thin bronchoscope. A 15-year-old girl with acute myeloid leukaemia had taken oral prednisolone, 60 mg/day, for graft versus host disease after haematopoietic stem cell transplantation. She was admitted to our hospital with fever and a large cavitary lesion in the right hilum. Using an ultra-thin bronchoscope, the interior of the cavity in the superior segment of the right lower lobe was observed. The bronchoscopic findings revealed debris adhering to the cavity wall with a small volume of effusion. Cunninghamella bertholletiae was isolated from the effusion specimen obtained using the bronchoscope. Pulmonary mucormycosis (C. bertholletiae) complicating an immunocompromised state was diagnosed. Ultra-thin bronchoscopy is useful to diagnose complex pulmonary infections and more research is needed to verify its clinical indications and utility.

Recommendation of a clinical impulse response analysis for catheter calibration-dumping coefficient and natural frequency are incomplete parameters for clinical evaluation.

OBJECTS: The damping coefficient and natural frequency are standard parameters for clinicians to evaluate the dynamic responses of pressure monitoring lines. But in fact, we had experienced some cases in which there were discrepancies between these parameters and frequency response curves. We tried to elucidate the defectiveness of the dumping coefficient and natural frequency with our new catheter calibration methods. METHODS AND RESULTS: At first we made a laboratory study with a function signal generator, a pressure wave converter, two pressure amplifiers and a personal computer. Using with our high-precision frequency response measurement method (step-response analysis) we clearly demonstrated the defectiveness of these parameters. Additionally a more sophisticated original method (clinical impulse response analysis) was also demonstrated in clinical recommendation, which makes it possible to measure true frequency response characteristics (system transfer function) without a function signal generator and a pressure wave converter, even in the operating room just after priming of the monitoring circuit without contamination. CONCLUSION: We recommend a clinical impulse response analysis for catheter calibration, instead of dumping coefficient and natural frequency.