Y-shaped catheter improves carbon dioxide clearance during apnoeic oxygenation in tracheal surgery

OBJECTIVES: Apnoeic oxygenation is a ventilation method in tracheal surgery, but has the disadvantage of causing progressive hypercapnia. The aim of this experimental study was to evaluate the efficacy of a Y-shaped catheter for the prevention of accumulation of carbon dioxide (CO2) in tracheal surgery. METHODS: Surgery for tracheal resection and reconstruction was performed in 10 beagles under general anaesthesia. Before transecting the trachea, the dogs were hyperventilated for 10 min with pure oxygen. After the airway was opened, ventilation was maintained with a small catheter for apnoeic oxygenation for 30 min until the end of the tracheal reconstruction. Y-shaped catheters were used in 5 dogs and straight catheters were used in 5 dogs for oxygen insufflation. Haemodynamic values and blood gas values were evaluated and compared between the 2 groups. RESULTS: The mean elevation in the CO2 partial pressure value per minute from 5 min after the start of the procedure to the end of apnoeic oxygenation was 1.34 mmHg [95% confidence interval (CI) 1.00-1.68] in the Y-shaped catheter group and 2.03 mmHg (95% CI 1.54-2.53) in the straight catheter group (P < 0.018). The total CO2 partial pressure elevation value was 59.5 mmHg in the Y-shaped catheter group and 89.0 mmHg in the straight catheter group (P < 0.006). There were no significant differences in haemodynamic values between the 2 groups. CONCLUSIONS: Apnoeic oxygenation using a Y-shaped catheter represses the accumulation of CO2 compared with a straight catheter in canine tracheal resection-reconstruction surgery.