Assisted pressure control ventilation via a mini-tracheostomy tube for postoperative respiratory management of lung cancer patients

Abstract

Assisted pressure control ventilation (PCV) via a min-tracheostomy tube (MTT) was conducted to improve gas exchange and reduce the work of breathing of lung cancer patients after surgery. Thirty-two patients with lung cancer underwent lobectomy and were managed postoperatively by assisted PCV via an MTT. On the basis of a simulation study using a lung model for clinical use, we set the inspiratory pressure to 20 cmH2O and inspiratory time to 1.0 sec to produce a 450-ml supported volume via the MTT per breath. The blood gases and respiratory rate of each patient were measured under three sets of conditions: PCV via an MTT transtracheal oxygenation (TTO) via an MTT and a Venturi face mask with the same FiO2. After PCV via an MTT overnight, the blood gases in the room air were measured 2.5 h after withdrawing PCV. In order to determine the effect of PCV via an MTT on gas exchange after PCV withdrawal, 32 other age and sex-matched lung cancer patients, who had undergone lobectomy and oxygenation via a face mask alone after surgery, were used as historical controls. The simulation study showed that the ventilated volume provided by assisted PCV via an MTT was about half that provided via a conventional endotracheal tube, even in the presence of air leakage. The clinical application showed that the ventilated volume obtained with the PCV via an MTT was significantly higher than that with spontaneous breathing (P < 0.001). PCV via an MTT increased the PaO2 and reduced both the PaCO2 and respiratory rate significantly in comparison with TTO via an MTT and a face mask (P < 0.001). After PCV withdrawal the morning after surgery, the PaO2 of the PCV group was significantly higher than that of the historical controls (P < 0.001). No postoperative pulmonary complications were observed in either the PCV or the control groups, however. In addition, no complications or morbidity were seen related to either MTT insertion or PCV via an MTT. Assisted PVC via an MTT increased the tidal volume, improved the gas exchange, reduced the respiratory rate by providing adequate ventilatory support and increased the PaO2, even after withdrawal following lung surgery. Even though we did not observe any benefit of clinical outcome with PCV via an MTT in the present study, this procedure appears to be a potentially useful respiratory management modality for patients with high risk of postoperative pulmonary complications. © 2000 HARCOURT PUBLISHERS LTD.