Table 3. Mehta’s rule of 4: laser with flexible bronchoscopy.
| Maximum length of lesion: 4 cm |
| Duration of lung collapse <4 weeks |
| Life expectancy >4 weeks |
| Procedure time <4 hours |
| FiO2 during laser therapy <40% |
| Number of pulses between cleaning <40 |
| Total number of repeat laser treatment <4 |
| Laser team: 4 persons |
| Initial settings |
| Noncontact: 40 Watts |
| Contact: 4 Watts |
| Pulse duration: 0.4 seconds |
| Distance |
| Endotracheal tube to lesion >4 cm |
| Fiber tip to lesion: 4 mm |
| Flexible bronchoscopy to tip: 4 mm |
FiO2, fraction of inspired oxygen.