Pulmonary circulation and gas exchange were observed during and after prostaglandin E_1-indueed hypotention in 9 adult mongrel dogs undergoing procaine balanced anesthesia. Cardiac index decreased from 12.5% to 13% (P0.05) during hypotension but the effective ratios of oxygen increased(P

Objective To investigate the advantage and safety of penehyclidine hydrochloride as the antagonist of muscle relaxant in aged patients with myocardial ischemia. Methods Sixty cases over 60 years old with myocardial ischemia in ECG were randomized to receive 15 ?g/kg atropine+40 ?g/kg neostigmine (group A),sole 20 ?g/kg penehyclidine hydrochloride (group B),20 ?g/kg penehyclidine hydrochloride +40 ?g/kg neostigmine (group C). Vital signs of antagonism were observed before and after the changes of antagonism. Results All cases had an uneventful anesthesia and operation. After antagonists were administered,heart rate and heart rate variation index increased,respiration became shallow and faster in group A. The heart rate in group B only increased mildly and the muscle tone returned very slowly as the increasing of BIS. The signs were the most desirable such as mildly lower heart rate,the minimal heart rate variation index,faster recover of muscle tone without re-relaxation,slow and deep respiration,and slowly recovered BIS. Conclusion Penehyclidine hydrochloride combined with neostigmine is suitable to reverse the muscle relaxant in aged with myocardial ischemia.