A prototype small‐bore ventilation catheter with a cuff: cuff inflation optimizes ventilation with the Ventrain

BACKGROUND: Ventilation through small‐diameter tubes typically precludes use of a cuff as this will impede the necessary passive outflow of gas alongside the tube's outer surface. Ventrain assists expiration and enables oxygenation and normoventilation through small‐bore cannulas or catheters, particularly in obstructed airways. A small‐bore ventilation catheter (SBVC; 40 cm long, 2.2 mm inner diameter) with a separate pressure monitoring lumen and a cuff was developed. Efficacy of oxygenation and ventilation with Ventrain through this catheter was investigated in sealed and open airways in a porcine cross‐over study. METHODS: Six pigs were ventilated with Ventrain (15 l/min oxygen, frequency 30 breaths per min, I : E‐ratio 1 : 1) through the SBVC, both with the cuff inflated and deflated. Prior to each test they were ventilated conventionally until steady state was achieved. RESULTS: With an inflated cuff, PaO(2) rose instantly and remained elevated (median [range] PaO(2) 61 [52–69] kPa after 30 min; P = 0.027 compared to baseline). PaCO(2) remained stable at 4.9 [4.2–6.2] kPa. After cuff deflation, PaO(2) was significantly lower (9 [5–28] kPa at 10 min, P = 0.028) and interventional ventilation had to be stopped prematurely in five pigs as PaCO(2) exceeded 10.6 kPa. Pulmonary artery pressures increased markedly in these pigs. Intratracheal pressures were kept between 5 and 20 cmH(2)O with the cuff inflated, but never exceeded 2 cmH(2)O after cuff deflation. CONCLUSION: The SBVC combines the benefits of a small diameter airway and a cuff. Cuff inflation optimizes oxygenation and ventilation with Ventrain.