VivaSight-SL™ Versus Bronchoscopy for Percutaneous Tracheotomy

Background

Long-term ventilated critically ill patients often receive a tracheotomy to facilitate weaning from the ventilator and for prevention of secondary complications by the endotracheal tube [1]. Besides surgical tracheotomy in which a muco-cutaneous fistula is prepared between trachea and outer skin, percutaneous tracheotomy (PDT) has been introduced, in which a cannula is being inserted into the trachea. After introduction of a guidewire, the trachea is then dilated [2]. This intervention should be led by optical guidance, i. e. to verify the correct point of tracheal cannulation between the 2nd and 3rd tracheal cartilage and to minimize the risk for accidental injury to the membranous part of the trachea [3]. Usually, optical guidance is performed by bronchoscopy [4]. During bronchoscopy in ventilated patients, a drop in minute ventilation or an increase of carbon dioxide partial pressure with a consecutive respiratory acidosis may occur. Recently, an endotracheal tube with an integrated camera at its tip has been introduced that permits a continuous visualization of the trachea on a monitor connected to the camera (VivaSightTM-SL, ETView Ltd., Misgav, Israel) [5]. This tube has been CE and FDA certified (http://www.etview.com/products/ vivasight-sl).

In this study, it is being evaluated whether the optical guidance during PDT can be performed by the VivaSightTM-SL tube. Without the need for bronchoscopy during intervention, patients' ventilation during the procedure may be optimized with a lesser increase of the arterial and the end-expiratory carbon dioxide partial pressures. Furthermore, the procedure itself would be simpler without the need for a bronchoscopy.

In the investigators' institution, the VivaSightTM-SL tube has already been used in two patients together with bronchoscopic guidance for percutaneous tracheotomy. According to the investigators' experience, it seems to be possible to perform the procedure without a bronchoscopy. Therefore, the feasibility of PDT with guidance by the VivaSightTM-SL tube alone without bronchoscopy is tested. After a positive result in the first part of this study, non-inferiority of the VivaSightTM-SL tube in comparison to bronchoscopy is tested.

Methods

Design of Study / No. of Patients:

part 1: observational study, 10 consecutive patients part 2: randomized, prospective study, 46 patients

With a sample size of 46 (randomized 1:1 in 2 groups of 23 each) a difference of 35% on a visualization score [6] may be seen with an α-error of 0,05 and a β-error of 1-0,8.

Procedures:

• screening of for study inclusion according to inclusion and exclusion criteria
• changing of the endotracheal tube to the VivaSightTM-SL tube
• percutaneous tracheotomy with Ciaglia Blue Rhino technique [2, 7, 8]
• arterial blood gas sampling (BGA): baseline value from patients' records, prior to skin incision, immediately after insertion of tracheal tube study inclusion:

All patients being treated in the Dept. of Intensive Care Medicine receiving percutaneous tracheotomy due to long term ventilation are screened according to inclusion and exclusion criteria.

Details of study-procedures:

Intubation:

The Intubation with the VivaSightTM-SL endotracheal tube does not differ from an intubation with a conventional tube that is done with respect to the standard operating procedure (SOP) of the Dept. for Intensive Care Medicine. During the intubation, vital parameters are monitored with respect to the underlying disease and patients' therapy is continuously adjusted. According to the SOP, two physicians are present of which at least one is a fellow or an attending physician with experience in intensive care medicine.

bronchoscopy:

The bronchoscopy for percutaneous tracheotomy is done according to the SOP of the Dept. for Intensive Care Medicine. Furthermore, during this study the bronchoscopy is done by a physician with an experience of more that 200 bronchoscopies.

percutaneous tracheotomy:

The tracheotomy is performed according to the Ciaglia Blue Rhino method [2, 7, 8] (Ciaglia Blue Rhino® G2, Cook Medical, Bloomington, IN, USA). After skin incision and an optional blunt dissection of the subcutaneous tissue, the trachea is cannulated between the 2nd and 3rd tracheal cartilage. Visualization is provided by either the VivaSightTM-SL tube or by conventional bronchoscopy. Should visualization be insufficient (one item of score ≥ 3, see below), a bronchoscope is available as a back-up. The tracheotomy is performed by an experienced fellow or attending physician.

rating of visualization of tracheal structures and ventilation during percutaneous dilatational tracheostomy (mod. after [6]):

Rating (each item 1 to 4 points)

1. Identification of: thyroid cartilage, cricoid cartilage, 1st-3rd tracheal cartilage

1 Reliable identification; 2 Only cricoid cartilage and tracheal cartilages; 3 Only tracheal cartilages; 4 No vision on tracheal structures

1. Visualization of tracheal circumference 1 Complete; 2 circumference 1/3 to 2/3 of circumference; 3 Only small parts of trachea; 4 No vision on tracheal structures
2. Monitoring puncture: midline + level below 1st or 2nd tracheal cartilage

1 Reliable identification; 2 Midline sure Level uncertain, but below the 1st tracheal cartilage; 3 Level of puncture uncertain; 4 No vision on tracheal structures

1. Monitoring dilatation Anterior wall and Pars membranacea (P.m.) visible; 1 Reliable identification; 2 P.m. only; 3 Only small parts of trachea visible, no control of P.m.; 4 No vision on tracheal structures
2. Quality of Ventilation Before puncture and worst ventilation during PDT, respectively

1 Minute ventilation (MV) as before starting tracheotomy; 2 MV < 2 L/min or oxygen saturation (SO2) 80-90% (>2minutes); 3 MV < 0,5l /min or SO2 70 - 79% (> 2 minutes); 4 MV = 0 or SO2 < 70% (> 2 minutes)

Consent: all patients or their legal surrogate give written informed consent.

Data protection: Data are anonymized.