Physiologic comparison between conventional mechanical ventilation and transtracheal open ventilation in acute traumatic quadriplegic patients

Objective: To evaluate the efficacy of mechanical ventilation administered through a small-boro, uncuffed tracheotomy tube, so-called transtracheal open ventilation (TOV), in comparison with conventional mechanical ventilation via a cuffed tracheal tube (endotracheal invasive ventilation, EIV). Design: Physiologic study. Setting: Intensive care unit of a referral trauma center. Patients: Ten acute quadriplegic patients. Interventions: In acute quadriplegic patients receiving EIV, TOV was subsequently applied via an uncuffed, small-bore tube (internal diameter of 4 or 5 mm). Measurements and Main Results: Compared with EIV, arterial blood gases were not significantly different after 1 hr of TOV (PaO₂/FIO₂, 222.8 ± 60.9 vs. 218.5 ± 60.3; PaCO₂, 37.8 ± 7.1 torr [5.04 ± 0.95 kPa] vs. 35.5 ± 6.8 torr [4.73 ± 0.91 kPa], for EIV and TOV, respectively). Respiratory rate (19.5 ± 4.7 vs. 19.6 ± 5 breaths/min) and inspiratory effort (pressure-time product of esophageal pressure during a 1-min period, 125.9 ± 48.4 vs. 112.8 ± 36.4 cm H₂O· sec^-1·min^-1) were also no different between the two modes. After 24 hrs of TOV, compared with EIV and TOV after 1 hr, respiratory rate and arterial blood gases remained stable, and the pressure-time product of esophageal pressure during a 1-min period was slightly, but significantly, reduced (83.5 ± 16.6 cm H₂O·sec ^-1·min^-1, p < .05). Conclusions: In acute quadriplegic patients receiving mechanical ventilation, TOV was as effective as EIV in providing ventilatory support.