Intrabronchial instillation

Sinus bradycardia. An abnormally low sinoatrial impulse rate (< 60/min) can be raised by parasympatholytics. The quaternary ipratropium is preferable to atropine, because it lacks CNS penetrability (p.108). Sympathomimetics also exert a positive chronotropic action they have the disadvantage of increasing myocardial excitability (and automaticity) and, thus, promoting ectopic impulse generation (tendency to extra-systolic beats). In cardiac arrest, epinephrine, given by intrabronchial instillation or intracardiac injection, can be used to reinitiate heart beat. 

Data obtained after either intravenous or intraperitoneal administration of chromium are difficult to interpret given the low uptake from the gastrointestinal tract. Intratracheal or intrabronchial instillation of chromium compounds and inhalation of chromiu-m(III) or chromium(VI) better mimic human occupational exposure (Gauglhofer and Bianchi 1991). 

---