Ultrathin-wall, two-stage, twin endotracheal tube: a tracheal tube with minimal resistance and minimal dead space for use in newborn and infant patients.

OBJECTIVE

To design and fabricate crush-proof polyurethane tracheal tubes for the newborn with the lowest resistance, least dead space, and thinnest wall.

DESIGN

Test and evaluation of a novel, low-resistance, and low-dead-space tracheal tube for newborns.

SETTING

National Institutes of Health Research Laboratory.

INTERVENTIONS

The short orotracheal portion of the tracheal tube was fabricated of polyurethane, reinforced with flat nickel-titanium shape-memory alloy (Nitinol) to render the tube crush-proof, of a wall thickness about one half of a standard tracheal tube. To the oral part of the tracheal tube, which is the sole dead-space, we attached a Y piece. We connected to one arm of the Y a nonreinforced (inspiratory) tube of larger internal diameter, and a similar tube (expiratory) to the other.

MEASUREMENTS AND RESULTS

The computed air flow resistance, as derived from the pressure/flow curves, is about one half to one third the resistance of a comparable standard tracheal tube at flow rates up to 8 L/min, with a tubing, connector, and adapter dead space three to seven times smaller, depending on the tracheal tube connector piece, the ventilator tube connector piece, and size of the tracheal tube.

CONCLUSIONS

The novel tracheal tube design has a resistance to gas flow one half to one third that of a standard tracheal tube and a dead-space volume three to seven times lower, including tubing and connector dead space. In addition, it offers a means for potential accurate, continuous online monitoring of expiratory oxygen and Co(2) concentration and gas flow, in both the inspiratory and the expiratory lines, without contributing to dead-space ventilation or gas flow resistance.