Objective: To compare in intubated patients manually ventilated in order to mirror the ventilator, the respiratory and hemodynamic effects induced by a bag device equipped with an inspiratory gas flow-limiting valve (Smart Bag, 0-Two Medical Technologies Inc., Mississauga, ON, Canada) and a Standard bag.
Design: Non-randomized crossover study comparing 13 respiratory and eight hemodynamically paired parameters. Eight intubated patients were manually ventilated, each by three different intensive care workers yielding 24 sets of data for comparison. Data were collected during two sessions of manual ventilation, first with the Standard bag and then with the Smart Bag. Between each session, the patient was reconnected to the ventilator until return to the baseline. Patients, included after coronary surgery, were sedated and paralyzed.
Setting: Intensive Care Unit, university hospital.
Results: Compared with Standard bag, the Smart Bag provided a decrease of inspiratory flow (23 +/- 4.7 vs. 47.3 +/- 16.5 l/min) with a decrease of peak pressure (13.3 +/- 2.9 vs. 21.9 +/- 7.3 cmH2O) and tidal volume (9.4 +/- 2.8 vs. 12.4 +/- 2.7 ml/kg). While the expiratory time was similar, the inspiratory time increased (1.83 +/- 0.58 vs. 1.28 +/- 0.46 s) with the Smart Bag, limiting the respiratory rate (14 +/- 5 vs. 17 +/- 6 cycles/min) and the minute volume (8.8 +/- 2.9 vs. 14.4 +/- 4.9 l/min). Finally, it limited the fall of the ETCO2 (27.9 +/- 5.1 vs. 24.3 +/- 5.7 mmHg) and probably the risks of severe respiratory alkalosis. The bags similarly affected hemodynamic states.
Conclusion: In intubated patients manually ventilated, the Smart Bag limits the risks of excessive airway pressure and the fall of the ETCO2, with hemodynamic effects similar to those of the Standard bag.