Feasibility and Safety of Dilatational Tracheotomy Using the Rigid Endoscope

A Multicenter Study

Andreas Nowak; Peter Kern; Sven Koscielny; Taras I. Usichenko; Klaus Hahnenkamp; Markus Jungehülsing; Matthias Tittel; Jens Oeken; Eckart Klemm

Disclosures

BMC Anesthesiol. 2017;17(7) 

In This Article

Discussion

PDT with TED was feasible in four study centers, and the time required for the PDT procedure (14.8 ± 6.2 [mean ± SD]) minutes was comparable with that the time required when using a flexible endoscope (13.6 ± 4.0).[9] The overall rate of complications (40.8%) was higher than the incidence reported in previous studies.[9] The complication rates of different PDT methods are difficult to compare because of the heterogeneity of observation periods and the differing classifications of the complications.[3,9] Review articles report an average complication rate of 26.0% in PDT.[9] In a previous study with trauma patients, PDT complications occurred in 37.4% of cases.[10] The most common complication during PDT with TED was fracture of the tracheal rings (17.1%), followed by desaturation (6.8%), special events (6.2%), anesthesia complications (4.5%), heavy bleeding (4.0%) and injuries to the posterior tracheal wall (1.1%). The higher overall complication rate in our study (40.8%) compared with other studies resulted from the accurate detection of tracheal ring fracture and its classification as a complication with the potential for late effects. During the three phases of PDT, complications such as bleeding and tracheal ring fracture were accompanied by an increase in the invasiveness of the procedure and tissue trauma caused by dilation of the trachea. However, most of these complications can be corrected by maintaining visualization with the use of the TED.

Bleeding

Bleeding during PDT is a frequent event occurring in 1.3–5.7% of patients;[1,11] in our investigation, clinically relevant bleeding was the fourth most common complication. The anatomical dead space volume of the tracheobronchial tree was calculated as 174 ml.[12] The tracheal bleeding usually spreads outward. Depending on volume, bleeding is nearly always found in the trachea, thus presenting an immediate vital complication even with small blood volumes.[7] Tracheal bleeding can lead to immediate desaturation. During flexible bronchoscopy, even several drops of blood may significantly impair the view, and the suction capacity of flexible bronchoscopes is limited. Possible bleeding into the trachea can be safely managed with clear endoscopic visibility of a rigid endoscope in combination with high-capacity suction tubes. In case of significant bleeding with risk of aspiration, the patient can be re-intubated with a cuffed endotracheal tube through the TED, and the surgeon can quickly convert the procedure to an open tracheostomy.[5]

Posterior Tracheal Wall Injuries

PDT-related injuries to the posterior tracheal wall occur in 0.7 to 2.6% of cases.[3,13] One superficial lesion of the posterior tracheal wall occurred during phase 1 because the puncture site was difficult to identify, and protection was abandoned through the puncture below the posterior lip of the TED. The second injury was caused when the dilator slipped in the patient's left main bronchus; the patient had a body mass index (BMI) of 41, an anatomically short neck with a crico-sternal distance (CSD) of 1 cm and a neck circumference of 44 cm. Such patients are at high risk for the lesions of the posterior tracheal wall, even in cases of elective endotracheal intubation.[14]

Tracheal Ring Fracture

Postmortem evidence of tracheal ring fracture caused by PDT and a reported incidence of up to 28.4% suggest that this complication is often under-diagnosed.[15] The incidence of tracheal ring fractures in our investigation (17.1%), which is probably the result of a sufficient view via TED, supports this finding. The assumed trachea-stabilizing effect of a rigid endoscope could not be detected in our study. The relevance of tracheal ring fractures in the development of tracheal stenosis is obvious but not fully understood. The development of tracheal stenosis after untreated tracheal ring fractures is probable,[16,17] and the possibility of immediate treatment of tracheal ring fragments after tracheal ring fracture may be an advantage of the TED.

Pneumothorax

The incidence of pneumothorax after PDT (0.6%) is rather low but can be life threatening if undetected.[11] Pneumothorax may result from incorrect puncture caused by injury to the para- or pre-tracheal space or the paratracheal tissues.[18] Additionally, the insertion of a flexible bronchoscope may rupture the lung parenchyma, causing endotracheal tube obstruction and consequent dynamic hyperinflation. Endoscopy with TED ensured adequate control of all procedural steps so that no pneumothorax resulted. Additionally, with TED, the airway remains open, and hyperinflation of the lungs as a result of air trapping does not occur.

Anesthesia Complications

Anesthesia complications were closely linked to desaturation, insufficient ventilation and a need for vasopressor support in intensive care patients. When patients ventilated with HFJV had been excluded from the analysis, the incidence of desaturation was 3.3%, similar to previous reports.[3] In clinical practice, respiratory and circulatory stability is commonly compromised in ICU patients because of disturbed vascular reactivity resulting from the underlying pulmonary impairment and prolonged immobilization. Therefore, the presence of an additional anesthesiologist or intensive care physician is recommended. An endotracheal tube puncture with leakage and subsequent altered ventilation can occur in 0.4 to 17% of cases with all methods of PDT using flexible endoscopy,[8] except for TED.

Dental Damage

We assume that the probability of tooth damage might be higher with TED than during fiberoptic tracheoscopy. Per oral rigid endoscopic procedures are commonly used in ENT surgery. For rigid endoscopy in ENT surgery, tooth damage is reported for 0.15% patients.[11] Because the TED is introduced from the right corner of the patient's mouth, the teeth and periodontal apparatus of position 11 to 15 of the right upper jaw and 41 to 45 of the right mandible are in focus during rigid endoscopy. In our study, one-third of patients were toothless, and 22% of patients had loose teeth. The only case of the removal of a tooth, which was loose because of carious damage prior to the PDT, confirms the low incidence of dental lesions during rigid endoscopy.

Management With TED

Loss of the airway during PDT may have fatal consequences. During PDT with or without fiberoptic control, intraoperative airway loss occurs in 1.9% to 7.4% of cases.[19,20] The risk of airway loss increases if the cuff of the endotracheal tube must be withdrawn into the larynx because of a tracheal puncture. During PDT using TED, airway loss does not occur. In particular, we showed the feasibility of inserting a rigid endoscope with an endotracheal tube as a guide. A total of 16 patients were intubated with the TED without the recommended guidance of an endotracheal tube. All cases of difficult introduction of the TED and one case of unsuccessful introduction of the TED occurred because of the failure to insert the rigid TED using the endotracheal tube. This factor emphasizes the importance of using the endotracheal tube as a guide. The beveled distal opening of the rigid tracheotomy endoscope should face laterally along the tube while it is introduced into the larynx. Overall, with skilled hands and the use of the endotracheal tube as a guide, the introduction of the TED is considered safe. The time required for PDT with TED is acceptable but not precisely comparable to published data for PDT with flexible bronchoscopy.[3,9]

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