Table 1 Rating scale for the visualization of tracheal structures and ventilation during percutaneous dilatational tracheostomy
Rating | 1 | 2 | 3 | 4 | |
|---|---|---|---|---|---|
A | Identification of thyroid cartilage, cricoid cartilage, first to third tracheal cartilage | Reliable identification | Only cricoid cartilage and tracheal cartilages | Only tracheal cartilage | No vision of tracheal structures |
B | Visualization of tracheal circumference | Complete circumference | One-third to two-thirds of circumference | Only small parts of trachea | No vision of tracheal structures |
C | Monitoring puncture midline + level below first or second tracheal cartilage | Reliable identification | Midline can be displayed, level uncertain, but below the first tracheal cartilage | Level of puncture uncertain | No vision of tracheal structures |
D | Monitoring dilatation anterior wall and pars membranacea (p.m.) visible | Reliable identification | p.m. only | Only small parts of trachea visible, no control of p.m | No vision of tracheal structures |
E | Quality of ventilation before puncture and worst ventilation during PDT, respectively | Minute ventilation (MV) as before starting PDT | MV < 2 L/minute or SpO2 80–90% (> 2 min) | MV < 0.5 L/minute or SpO2 70–79% (> 2 min) | MV = 0 or SpO2 < 70% (> 2 min) |
F | Quality of suction tube for suction of viscous mucus | Easy suction | Suction requires lavage | Suction requires multiple removals of bronchoscope and lavage | Suction not possible |
G | Handling of bronchoscope | easy | Impeded, all parts of the bronchial system visible | Intubation of one segment not possible | Intubation of more than one segment not possible |