To the theory of bronchial asthma

In bronchial asthma, most authors now see, as is known, a kind of neurosis of the respiratory apparatus, and they accept that asthma attacks are the result of specific irritation of the respiratory center (Briigelmann, Hoffman)

On the use of inhalations of carbon dioxide in surgery according to Dzialoszunskiy (Zentr. f. Chir., 1926, No. 23)

According to Dzialoszunsky (Zentr. F. Chir., 1926, No. 23), carbon dioxide during inhalation causes strong irritation of the respiratory center and deep and frequent breathing. Due to a noticeable increase in respiratory activity, the inhaled drug is released from the body faster, the lungs are ventilated down to the smallest bronchi, and a secret is released that fills the respiratory tract.

Ventilatory response to CO2 with Read's rebreathing method in normal infants

Background Methods of evaluating the ventilatory response to CO2 (VRCO2) of the respiratory center include the steady-state and the rebreathing method. Although the rebreathing method can evaluate the respiratory center more in detail, the steady-state method has been mainly performed in infants. The aim of this study was to investigate whether we could perform the VRCO2 with the rebreathing method in normal infants. Methods The subjects were 80 normal infants. The gestational age was 39.9（39.3-40.3）weeks, and the birth body weight was 3,142 (2,851-3,451) grams. We performed the VRCO2 with Read’s rebreathing method, measuring the increase in minute volume (MV) in response to the increase in EtCO2 by rebreathing a closed circuit. The value of VRCO2 was calculated as follow: VRCO2 (mL/min/mmHg/kg) = ΔMV / ΔEtCO2 / Body weight. Results We performed the examination without adverse events. The age in days at examination was 3 (2-4), and the examination time was 150±38 seconds. The maximum EtCO2 was 51.1 (50.5-51.9) mmHg. The value of VRCO2 was 34.6 (29.3-42.8). Tidal volume had a greater effect on the increase in MV than respiratory rate (5.4 to 14.3 mL/kg, 44.1 to 55.9 /min, respectively). Conclusion This study suggests that the rebreathing method can evaluate the ventilatory response to high blood CO2 in a short examination time. We conclude that the rebreathing method is useful even in infants. In the future, we plan to measure the VRCO2 of preterm infants, and evaluate the respiratory center of infants in more detail.

Endogenous hydrogen sulfide maintains eupnea in an in situ arterially perfused preparation of rats

Hydrogen sulfide (H2S) is constitutively generated in the human body and works as a gasotransmitter in synaptic transmission. In this study, we aimed to evaluate the roles of endogenous H2S in generating eupnea at the respiratory center. We employed an in situ arterially perfused preparation of decerebrated rats and recorded the central respiratory outputs. When the H2S-producing enzyme cystathionine β-synthase (CBS) was inhibited, respiration switched from the 3-phase eupneic pattern, which consists of inspiration, postinspiration, and expiration, to gasping-like respiration, which consists of inspiration only. On the other hand, when H2S synthesis was inhibited via cystathionine γ-lyase (CSE) or when H2S synthesis was activated via CBS, eupnea remained unchanged. These results suggest that H2S produced by CBS has crucial roles in maintaining the neuronal network to generate eupnea. The mechanism of respiratory pattern generation might be switched from a network-based system to a pacemaker cell-based system in low H2S conditions.