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From the *Department of Surgery, Division of Anesthesiology and Intensive Care, University of Pisa, Pisa, Italy; Department of Intensive Care, Anaesthesia and Analgesia, Versilia Hospital, Lidodi Camaiore, Italy; and Department of Anesthesiology, The University of Texas Medical School, Houston, Texas.
Address correspondence and reprint requests to Carin A. Hagberg, MD, Professor, Department of Anesthesiology, The University of Texas Medical School at Houston, 6431 Fannin, MSB 5.020, Houston, TX 77030. Address e-mail to carin.a.hagberg{at}uth.tmc.edu.
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Abstract |
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 Top Abstract IntroductionMETHODSRESULTSDISCUSSIONREFERENCES |
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Introduction |
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TopAbstractIntroductionMETHODSRESULTSDISCUSSIONREFERENCES |
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These techniques all have similar complication rates (9–11), which can occur early (during the procedure and <24 h) or late (>24 h after the procedure). Complications that can occur during these procedures include bleeding, creation of a false passage, pneumothorax, emphysema of the neck, puncture of the posterior wall of the trachea, and perforation of the esophagus. The risk of these complications can be dramatically reduced if the procedure is performed under continuous endoscopic guidance (11).
Traditionally, endoscopy is performed through an endotracheal tube. Furthermore, when performed with an endotracheal tube, the procedure requires that the cuff of the endotracheal tube be deflated and the tube be withdrawn until the cuff is located at the level of the vocal cords. Failure to position the endotracheal tube correctly can result in further complications during the course of the procedure, such as rupture of the tube cuff, transection of the tube with the needle, inability to ventilate, and accidental tracheal extubation. Any of these complications can result in life-threatening hypoxia.
Replacing an endotracheal tube with a Laryngeal Mask Airway (LMA) as a conduit for the fiberoptic bronchoscope avoids some of these risks and provides superior visualization of the trachea and larynx. Despite the theoretical advantages of the LMA, Ambesh et al. (12), found, in a comparative prospective study, that 33% of patients in the LMA group suffered potentially catastrophic complications, and that these patients were at significant risk for hypoxia and aspiration of gastric contents. Few studies have demonstrated the effectiveness and safety of the LMA during the percutaneous dilatational tracheostomy procedure (13–15). Of these, only one (14) is a comparative prospective study and, although Dosemeci et al. did show fewer overall complications with the LMA, the difference was not statistically significant. Also, as this study was unblinded a bias was introduced. Because there is conflicting evidence in the literature regarding the safety and reliability of using the LMA in daily clinical activity for airway control during bronchoscopic-assisted guidewire dilatating forceps procedures, a retrospective investigation was performed at our institution.
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METHODS |
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The procedure was done using continuous bronchoscopic guidance, with ventilation being performed through a Classic LMA (LMA North America, San Diego, CA) unless the patient had a contraindication to the use of a LMA, such as obesity, patients considered to be difficult to intubate (history of a difficult intubation, short thick neck, generalized edema, small receding chin, large tongue, thyromental distance of <3 finger breadths, reduced neck mobility), and those with significant inflammation of the upper airway (edema, laryngitis or epiglottitis) or those who required peak airway pressures >30 cm H2O (16,17). An LMA was also not used if the anesthesiologist preferred using an endotracheal tube for the procedure.
All patients were fasted at least 6 h before the surgical procedure. Patients received ketamine 1–2 mg/kg or midazolam 0.1–0.2 mg/kg and fentanyl 1–2 µg/kg for sedation and atracurium 0.5–0.6 mg/kg for neuromuscular blockade. Immediately before the onset of the procedure, the fraction of inspired oxygen was increased to 1.0, the pharynx was suctioned, and the nasogastric tube was suctioned but left in situ during the procedure.
All patients' heads were extended with a roll placed under their shoulders. The neck and the upper thorax were prepared with tincture of iodine and local anesthesia was provided by injection of 2% lidocaine with epinephrine 1:100,000 to improve patient tolerance for the procedure and reduce bleeding. In Group I, the endotracheal tube was removed and an LMA was inserted. The LMA size was chosen as recommended by the manufacturer: #3 <50 kg, #4 50–70 kg, and #5 >70 kg. In Group II, the endotracheal tube was withdrawn under direct vision, with a laryngoscope, until the inflated cuff was located between the vocal cords. Once adequate oxygenation and ventilation was confirmed, the PT commenced. The guidewire dilatating forceps technique was performed with a Percutaneous Tracheostomy Kit (SIMS Portex Limited, Hythe, Kent, UK) (Fig. 1). The trachea was entered with a cannulated needle followed by passage of a guidewire once the needle was removed. The position and depth of the tracheal puncture, as well as the position of the guidewire, were routinely checked with a fiberoptic bronchoscope in all patients. Subsequently, the forceps were used to dilate the tracheal wall (Fig. 2).
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Patient demographics were recorded. The patients were monitored in the intensive care unit as per standard protocol. Any complications occurring during the procedure or within 24 h after the procedure were recorded as early complications. Any complications that occurred more than 24 h after the procedure, but before discharge, were recorded as late complications.
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RESULTS |
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Table 1 demonstrates early and late complications between the study groups. Four of 188 (2.12%) patients in Group I experienced complications. Three patients (1.59%) experienced bleeding and 1 patient (0.53%) developed a pneumothorax within the first 24 h after the procedure. Six of 66 (9.09%) patients in Group II experienced complications. Bleeding, accidental extubation, and rupture of the endotracheal tube cuff occurred in 6 patients (2 of each) within the first 24 h. There were no late complications in either group. Of the patients who underwent open tracheostomy (n = 20), 6 (30.0%) experienced bleeding within the first 24 h and 3 (15.0%) experienced bleeding after the first 24 h. One (5.0%) patient developed tracheal stenosis.
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Significant differences were found in acute complications (bleeding, hypoxia, pneumothorax) between the Classic LMA and endotracheal tube groups (4 of 188 versus 6 of 66; P = 0.022 Fisher's exact test, odds ratio = 4.6). Significant differences were found in acute complications (10 of 254 versus 6 of 20; P < 0.001, odds ratio = 10.5) and chronic complications (tracheal stenosis) (0 of 254 versus 4 of 20; P < 0.001) between the guidewire dilatating forceps and surgical tracheostomy procedures.
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DISCUSSION |
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TopAbstractIntroductionMETHODSRESULTSDISCUSSIONREFERENCES |
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By performing this procedure under continuous bronchoscopic guidance, the needle and guidewire can be correctly placed and dilation can be carefully performed under fiberoptic visualization, thus reducing the risk of complications. However, to accomplish this through an endotracheal tube, the endotracheal tube must be withdrawn so that the cuff is located at the level of the vocal cords and the cuff must be partially deflated. This could lead to accidental extubation and loss of the airway, with fatal consequences. Also, withdrawing the endotracheal tube does not guarantee that the endotracheal tube or its cuff will not get punctured. This is because the anatomical length of the adult human larynx is 3.4–4.4 cm (20). In a size 8.0–9.0 mm endotracheal tube, the average length of the cuff is 3 cm and the average length of the tube from the distal end of the cuff to the tip of the endotracheal tube is 3 cm; therefore, it is possible that even if the endotracheal tube is withdrawn, the tube itself or the cuff could be punctured by the tracheostomy needle. This could lead to a loss of airway pressure and an inability to effectively ventilate the lungs, possibly resulting in devastating consequences.
An additional problem with the endotracheal tube is visualization with the fiberoptic bronchoscope. To obtain a clear, undistorted view of the procedure through the fiberoptic bronchoscope, the tip of the fiberoptic bronchoscope should be located at or beyond the tip of the endotracheal tube. As discussed above, this may be positioned directly at or distal to the tracheostomy needle insertion point, and therefore the view may be suboptimal to assess correct placement of the needle and guidewire.
The Classic LMA may be used to overcome these potentially devastating complications. This study demonstrates that the use of a Classic LMA for airway management during guidewire dilatating forceps PT procedures had significantly fewer complications than when performed using an endotracheal tube.
In addition to our study, numerous other studies have shown that the Classic LMA facilitates fiberoptic guidance and allows an undistorted view of the larynx and trachea, thus assisting the operator to confirm accurate positioning of the needle in the trachea (13–15,21,22). The LMA is easy to insert blindly and is a safe and effective means of providing positive pressure ventilation. Also, because the LMA is a supraglottic ventilatory device, the risk of penetrating it with the tracheostomy needle is virtually eliminated. On the other hand, the Classic LMA does not protect against aspiration (23); therefore it should be avoided in patients who are at high risk for aspiration. As an added precaution, an orogastric or nasogastric tube should be placed and the stomach contents suctioned before the procedure and it should remain in situ throughout the procedure. Gastroesophageal reflux disease was not considered a contraindication to the use of a LMA in our study, as those with history of gastroesophageal reflux disease were fasted for at least 6 hours before the procedure and their stomach contents were suctioned. Furthermore, the ProSeal LMA, a laryngeal mask with an esophageal vent, could be used to allow direct gastric drainage, thus minimizing the risk of aspiration and regurgitation (24).
Also, although we considered obesity a contraindication for the use of a Classic LMA in our study, Sustic et al. (25) report a case in which a LMA was used successfully during insertion of a PT using ultrasound guidance. It is also important to mention that although an LMA does not protect against aspiration in high risk patients, neither does an endotracheal tube with a deflated or ruptured cuff.
The limitations of this study are as follows: this was a retrospective study, thus the patients were not randomized, the operators were not blinded, and the data are not comparative. The patients who had the procedure performed with an endotracheal tube were usually more critically ill and were assessed to have more difficult airways. Furthermore, the degree of visualization through either the Classic LMA or the endotracheal tube was subjective, and there was no objective method used to grade the degree of visualization.
Despite the limitations of this study, we demonstrated that the Classic LMA is a safe and effective alternative to the endotracheal tube for airway management during guidewire dilatating forceps PT in selected patients. This represents the largest analysis of using LMAs for airway management during these procedures. Although using LMAs avoids some of the inherent risks associated with percutaneous tracheostomy procedures, there are limitations with their use. Although the ProSeal LMA may be more beneficial as compared with the Classic LMA during PT, the Classic LMA remains a valuable option when reasonable precautions are taken. Further investigation is required to determine which patients will benefit most from this method. Finally, further studies using the ProSeal LMA for airway management in these procedures are warranted.
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ACKNOWLEDGMENTS |
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Footnotes |
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This article has been cited by other articles:
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  C. A. Hagberg and D. Cattano The Laryngeal Mask Airway for Airway Management During Percutaneous Tracheostomy: Everything Should Be Made as Simple as Possible but Not Simpler Anesth. Analg., March 1, 2007; 104(3): 744 - 745. [Full Text] [PDF]
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M. Beiderlinden and M. Eikermann The Laryngeal Mask Airway for Airway Management During Percutaneous Tracheostomy: Everything Should Be Made as Simple as Possible but Not Simpler Anesth. Analg., March 1, 2007; 104(3): 743 - 744. [Full Text] [PDF]
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