Volume control mode: Guide for positioning of laryngeal mask airway

Laryngeal mask combined with bronchial blocker provides an alternative for lung isolation but lacks adequate access to the non-dependent lung. Substituting the blocker with a bronchial tube may overcome this limitation. In this report, a #4.5 cuffed bronchial tube was introduced into the non-dependent lung through a second-generation laryngeal mask for transthoracic oesophagectomy. During the 2.5-hour thoracotomy, one-lung ventilation was achieved by isolating the left lung with the bronchial tube and ventilating the right lung via the laryngeal mask, using volume-control mode (7 mL/kg × 12/min) with PIP21–23 cm H2O, pH 7.36 and PaCO2 38.3. Prior to thoracotomy closure, suction and reinflation of the left lung were performed through the bronchial tube. Bronchoscopy via the laryngeal mask revealed no injury to the airway after removal of the bronchial tube. The case shows that laryngeal mask combined with bronchial intubation provides one-lung ventilation with access to the isolated lung.

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Effects of Peak Inspiratory Flow on Development of Ventilator-induced Lung Injury in Rabbits

Anesthesiology ◽

10.1097/00000542-200409000-00021 ◽

2004 ◽

Vol 101 (3) ◽

pp. 722-728 ◽

Cited By ~ 57

Author(s):

Yoshiko Maeda ◽

Yuji Fujino ◽

Akinori Uchiyama ◽

Nariaki Matsuura ◽

Takashi Mashimo ◽

...

Keyword(s):

Mechanical Ventilation ◽

Lung Injury ◽

Cycle Time ◽

Inspiratory Flow ◽

Control Mode ◽

Volume Control ◽

Control Group ◽

Inspiratory Time ◽

Peak Inspiratory Flow ◽

Volume Control Mode

Background A lung-protecting strategy is essential when ventilating acute lung injury/acute respiratory distress syndrome patients. Current emphasis is on limiting inspiratory pressure and volume. This study was designed to investigate the effect of peak inspiratory flow on lung injury. Methods Twenty-four rabbits were anesthetized, tracheostomized, ventilated with a Siemens Servo 300, and randomly assigned to three groups as follows: 1) the pressure regulated volume control group received pressure-regulated volume control mode with inspiratory time set at 20% of total cycle time, 2) the volume control with 20% inspiratory time group received volume-control mode with inspiratory time of 20% of total cycle time, and 3) the volume control with 50% inspiratory time group received volume-control mode with inspiratory time of 50% of total cycle time. Tidal volume was 30 ml/kg, respiratory rate was 20 breaths/min, and positive end-expiratory pressure was 0 cm H2O. After 6 h mechanical ventilation, the lungs were removed for histologic examination. Results When mechanical ventilation started, peak inspiratory flow was 28.8 +/- 1.4 l/min in the pressure regulated volume control group, 7.5 +/- 0.5 l/min in the volume control with 20% inspiratory time group, and 2.6 +/- 0.3 l/min in the volume control with 50% inspiratory time group. Plateau pressure did not differ significantly among the groups. Gradually during 6 h, Pao2 in the pressure regulated volume control group decreased from 688 +/- 39 to a significantly lower 304 +/- 199 mm Hg (P < 0.05) (mean +/- SD). The static compliance of the respiratory system for the pressure regulated volume control group also ended significantly lower after 6 h (P < 0.05). Wet to dry ratio for the pressure regulated volume control group was larger than for other groups (P < 0.05). Macroscopically and histologically, the lungs of the pressure regulated volume control group showed more injury than the other groups. Conclusion When an injurious tidal volume is delivered, the deterioration in gas exchange and respiratory mechanics, and lung injury appear to be marked at a high peak inspiratory flow.

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