Ju Yuel Park

Waveform analysis of tremor may help to differentiate Parkinson's disease from drug-induced parkinsonism

In this study, we analyzed the waveform characteristics of resting tremor by accelerometer recordings in patients with drug-induced parkinsonism (DIP) and Parkinsons disease (PD). We prospectively recruited 12 patients with tremulous PD and 12 patients with DIP presenting with resting tremor. Tremor was recorded from the more affected side and was recorded twice for a 60 s period in each patient. Peak frequency, amplitude and all harmonic peaks were obtained, and the asymmetry of the decay of the autocorrelation function, third momentum and time-reversal invariance were also computed using a mathematical algorithm. Among the parameters used in the waveform analysis, the harmonic ratio, time-reversal invariance and asymmetric decay of the autocorrelation function were different between PD and DIP at a statistically significant level (all p < 0.01). The total harmonic peak power and third momentum in the time series were not significantly different. The clinical characteristics of DIP patients may be similar to those of PD patients in some cases, which makes the clinical differentiation between DIP and PD challenging. Our study shows that the identification of parameters reflecting waveform asymmetry might be helpful in differentiating between DIP and PD.

Predictable normocapnoea in controlled ventilation of infants with Jackson Rees or Bain system

We have devised a formula for ventilator settings which would provide normal minute ventilation without rebreathing during controlled ventilation using a Jackson Rees or Bain system. As V T = V S + V F − V L, where V T = delivered tidal volume, V S = set tidal volume, V F = the volume of fresh gas entering during the inspiratory phase and V L = the lost volume due to the compliance of the system, V S was derived: V S = V L + V T × [1 − b/(1 + a)] where a = expiratory‐to‐inspiratory ratio and b = the ratio of fresh gas flow to the minute ventilation. It was evaluated in 62 infants. Arterial partial pressure of carbon dioxide (mean (SD)) was 4.6 (0.5) kPa (35 (4) mmHg) with a range of 3.42–5.78 kPa (26–44 mmHg). The 90th percentile was 5.1 kPa (39 mmHg). It is concluded that predictable normocapnoea can be conveniently achieved in infants in controlled ventilation with Jackson Rees or Bain system if our formula is applied.