Abstract

BACKGOUND: Mass casualties from organophosphorus inhalation die from respiratory depression. Gas supplies and equipment are limited for mechanical ventilation of multiple subjects in emergency situation. Endobronchial insufflation of air (EIA) can be simply performed with air compressor and catheter. The author tried to examine the usefulness of EIA in five apneic dogs induced by tetrodotoxin (TTX) infusion.
METHOD
Five anesthetized dogs were intubated with endotracheal tube and endobronchial insufflation catheter and instrumented with arterial catheter and ventilated with controlled mechanical ventilation (CMV) while 12 microgram/kg TTX was infused intravenous over 90 minutes to produce apnea. EIA of 1 microliter/kg/min was delivered through a 35 cm long, 0.8 cm ID catheter with a forked end placed astride the carina. During conventional ventilation, arterial blood gases and pH were measured (base line, BL). The data were measured after confirmation of apnea for 1 minute (time=0, control value), and then measured serially for 4 hours of EIA.
RESULT
All animals survived and were alert and neurologically normal within 24 hours. The changes of arterial oxygen tension (PaO2) were no significant difference between control value and 10, 20, 30 minute (p<0.05), and arterial carbon dioxide tension (PaCO2) were significant increase in control value compared to base line (p<0.05), and pH were no significant difference in all values (p<0.05). Spontaneous respiratory efforts slowly returned after 45 minute of EIA and resulted in the improvement of gas exchange.
CONCLUSION
EIA recognized as a sort of ventilatory technique is useful only when other equipments could not be available. The EIA catheter can be placed by cricothyroidotomy. EIA is very helpful in supporting ventilation, and it also helps the apneic dogs stay in normal condition.

• Keywords: Monitoring;blood gas;Toxicity;neurotoxicity;tetrodotoxin;Ventilation;apnea;endobronchial insufflation;