Bronchoscopy versus an endotracheal tube mounted camera for the peri-interventional visualization of percutaneous dilatational tracheostomy - a prospective, randomized trial (VivaPDT)

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 minutes)	MV < 0.5 L/minute or SpO₂ 70–79% (> 2 minutes)	MV = 0 or SpO₂ < 70% (> 2 minutes)

Abbreviations: MV Minute ventilation; PDT Percutaneous dilatational tracheostomy; p.m. Pars membranacea of the trachea, SpO ₂ Oxygen saturation as measured by pulse oximetry
From Grensemann et al. [12] (modified from Linstedt et al. [15])
Rating system: 1 = very good; 2 = good; 3 = difficult; 4 = impossible. The quality of ventilation (line E) was rated twice (i.e., before puncture [E1] and to reflect the worst ventilation during tracheostomy [E2])

ISSN: 1364-8535