Blue laser as a safe option in laser airway surgery.

Compare ventilation pressures of 2 endotracheal tube designs used in laser airway surgery in clinical practice and with a benchtop model to elucidate differences and understand the design elements that impact airflow dynamics. Ventilatory and aerodynamic characteristics of the laser resistant stainless-steel endotracheal tube (LRSS-ET) design and the laser resistant aluminum-wrapped silicone endotracheal tube (LRAS-ET) design were compared. Ventilatory parameters were collected for 32 patients undergoing laser-assisted airway surgery through retrospective chart review. An in vitro benchtop simulation measured average resistance and centerline turbulence intensity of both designs at various diameters and physiological frequencies. Baseline patient characteristics did not differ between the 2 groups. Clinically, the median LRAS-ET peak inspiratory pressure (PIP; 21.00 cm H2O) was significantly decreased compared to LRSS-ET PIP (34.67 cm H2O). In benchtop simulation, the average PIP of the LRAS-ET was significantly lower at all sizes and frequencies. The LRSS-ET consistently demonstrated an increased resistance, although no patterns were observed in turbulence intensity data between both designs. The benchtop model demonstrated increased resistance in the LRSS-ET compared to the LRAS-ET at all comparable sizes. This finding is supported by retrospective ventilatory pressures during laser airway surgery, which show significantly increased PIPs when comparing identically sized inner diameters. Given the equivocal turbulence intensity data, these differences in resistance and pressures are likely caused by wall roughness and intraluminal presence of tubing, not inlet or outlet geometries. The decreased PIPs of the LRAS-ET should assist in following lung protective ventilator management strategies and reduce risk of pulmonary injury and hemodynamic instability to the patient.

Surgical fires, particularly within Otolaryngology, remain a surprisingly frequent and devastating complication of laser-related surgery in the oropharynx and airway; Current estimates suggest anywhere from 200 to 600 surgical fires per year in the United States, with 20%-30% of these occurring as a complication of laser surgery and 90%-95% of these occurring in the head and neck region. Unfortunately, the complications of laser surgery in the airway may include respiratory failure, airway burns with stenosis, and may result in mortality. The most commonly utilized endotracheal tube for protection against inadvertent laser strikes, the Laser-Shield II tube (Medtronic), was removed from the commercial marketplace in 2016 after cases of airway fires were reported as a result of feature deficiencies in the product (FDA MAUDE Database review). Since the demise of the Laser-Shield II tube, alternatives such as the Mallinckrodt laser tube and handmade reinforced tubes have been utilized, although shortcomings in design and features have made these options less appealing to practicing Otolaryngologists. Creating a laser-safe endotracheal tube is critical for safe upper airway surgery. This paper evaluates new technologies, materials, and technical innovations in endotracheal tubes that may advance patient safety in laser-assisted Otolaryngology procedures. This paper evaluates new technologies, materials, and technical innovations in endotracheal tubes that may advance patient safety in laser-assisted Otolaryngology procedures. First, this article reviews the background of laser surgery in Otolaryngology and the consequent risk of surgical fire with resultant development of laser-resistant endotracheal tubes and commercial availability. Next, a review of claims and national database review of product failures related to previous laser-resistant endotracheal tubes is performed through the FDA MAUDE database. This includes an evaluation of cases: review of techniques in laser airway surgery including spontaneous ventilation, decreased O2 concentration, currently available endotracheal tubes including "handmade" fixes for perceived safety risks, and determination of failure points for previous laser-resistant endotracheal tubes. Third, the paper reviews the requested features of an "ideal" laser-resistant endotracheal tube. Finally, the paper reviews failure testing from an initial, unsuccessful attempt at material development and the consequent development of alternative technologies that address failure points from previous endotracheal tubes and addresses requested features with a detailed analysis of FDA-approval required testing. Extensive lab testing of the new tube predicts a significant reduction of risk in vivo with inability to perforate the shaft or cuff of the tubes under standard working conditions. While no iteration of a laser-resistant endotracheal tube is entirely laser safe, advances in technology can improve the safety profile of these devices. The new tube contains a double cuff, a soft and flexible shaft to minimize laryngeal insertion trauma, a smooth external surface, a tight-to-shaft balloon, and methylene blue dye in the cuff to alert the user to inadvertent penetration. These characteristics were the most requested by laryngologists in the development of a new laser-resistant tube. The newest endotracheal tube brings the features most requested by Otolaryngologists in a laser-resistant tube, and improves the safety profile over previous tubes. Development of a new endotracheal tube represents an advancement in safety for the Otolaryngologist in laser airway surgery. Understanding the previous history and the science behind surgical fire formation is essential in advancing safety for patients in the future. N/A Laryngoscope, 134:S1-S12, 2024.

The prevention laser induced tracheal tube fires necessitates the use of special anesthesia techniques. To assess the superiority of the Xomed (Jacksonville, FL) Laser Shield TM I tracheal tube to conventional tubes, we compared its combustibility to polyvinylchloride (PVC) and red rubber (RR) tracheal tubes. Methods: Size 6 Xomed, Mallinckrodt (Glens Falls, NY) PVC, and Rusch (Germany) RR tracheal tubes were studied. A Cooper (Santa Clara, CA) CO2 laser and operating microscope were used to focus the laser beam perpendicularly onto the tracheal tube shafts. Five Lmin-1 of O2 flowed through the tracheal tubes which rested on wet towels in air during the study. The laser was set for continuous operation and actuated until a blow torch fire occurred or 90 seconds had elapsed. Ten trials each at 15, 17, and 20 watts were done for the three types of tracheal tubes. ANOVA and Scheffe tests were performed. Results: The times to blow torch ignition of the PVC tracheal tubes were: (mean ± S>D>) 1.73±80, 1.76±0.73, and 1.53±0.42 seconds at 15, 17, and 20 watts respectively. For the Xomed tracheal tubes, blow torch ignition occurred at 85.93±80.80, 42.51±49.35, and 20.30±39.32 seconds at 15,17, and 20 watts, respectively. Blow torch fires of the RR tracheal tubes occurred after 24.49±2.64, 25.41±4.60, and 21.92±5.60 seconds at 15, 17, and 20 watts, respectively. The differences in the times to combustion of the PVC vs the Xomed tracheal tubes achieved statistical significance at 15 and 17 watts (P<0.05). Intra- luminal tracheal tube fires occurred after a significantly shorter time with the RR than with the Xomed tracheal tube at 15 watts (P<0.05). At 20 watts there were no statistically significant differences in the times to combustion of the three types of tracheal tubes tested. Discussion: The Xomed Laser Shield TM I tracheal tube is fabricated from silicone with a coating containing metallic particles. Our study shows that at 15 and 17 watts, a significantly longer duration of laser actuation was required for ignition of the Xomed tracheal tube than for PVC tracheal tubes. However, at 20 watts, the time to combustion of the Xomed tracheal tube was not significantly different from that of the PVC tracheal tube. Similarly, while at 15 watts, a longer period of laser contact was required for blow torch ignition of Xomed tracheal tubes than for the RR tracheal tubes, at 17 and 20 watts there was no significant difference in time to intraluminal combustion of these tubes. Furthermore, the Xomed tracheal tube is much more expensive than the RR or PVC tracheal tubes. Endotracheal tube fires have been shown to be the most common serious complication of laser airway surgery. In an attempt to prevent laser-induced airway fires, the Xomed Laser Shield I (XLS) tracheal tube was introduced. To assess its superiority to conventional tracheal tubes, we compared its combustibility to polyvinylchloride (PVC) and red rubber (RR) tracheal tubes. A CO2 laser and operating microscope were used to focus the laser beam perpendicularly onto the tracheal tubes shafts. Five L min-1 of oxygen flowed through the tracheal tubes which rested on wet towels in air during the study. The laser was set to continuous operation and actuated until a blow torch fire occurred or 1 minute had elapsed. Ten trials each at 15, 17, and 20 watts were done for the three types of endotracheal tubes. The times to blow torch ignition of the PVC tracheal tubes were: (Mean+ SD) 1.7+ 0.8, 1.8+ 0.7, and 1.5+ 0.4 at 15, 17 and 20 watts, respectively. For the XLS tracheal tubes, blow torch ignition occurred at 85.9 + 80.8, 42.5+ 49.4, and 20.3+ 39.3 at 15, 17 and 20 watts, respectively. Blowtorch fires of the RR tracheal tubes occurred after 24.5+ 2.6, 25.4+ 4.6, and 21.9+ 5.6 seconds at 15, 17 and 20 watts, respectively. The difference in the times to combustion of the PVC vs. XLS endotracheal tubes achieved statistical significance at 15 and 17 watts (P<0.05). At 20 watts there were no statistically significant differences in the times to combustion of the three tracheal tubes tested. We conclude that the RR, PVC, or XLS tracheal tubes provide inadequate protection from the CO2 laser and should not be used for laser airway surgery. Wrapping the tracheal tubes with an appropriate metallic foil tape or the use of a stainless steel tracheal tube is recommended instead.

The risk of an endotracheal tube's combustion during laser airway surgery necessitates the use of special anesthetic techniques and equipment to prevent this complication. This study was designed to evaluate the Laser-Trach(TM), a new laser-resistant rubber endotracheal tube for use during laser airway surgery. The Laser-Trach endotracheal tubes that were evaluated were size 6.0 mm internal diameter (ID) red rubber endotracheal tubes which had been commercially wrapped by Kendall-Sheridan (Mansfield, Mass.) with copper foil tape and overwrapped with fabric. The fabric layer was saturated with water prior to our tests, as recommended by the manufacturer. The Laser-Trach endotracheal tubes were compared with plain (bare) size 6.0 mm ID Rusch red rubber endotracheal tubes. The tubes under study were positioned horizontally on wet towels in air and had 5 L x min(-1) of oxygen flowing through them. They were subjected to continuous laser radiation at 40 W from either a CO2 or an Nd-YAG laser. The Nd-YAG laser was propagated via a 600-micron fiber bundle. Each laser was directed perpendicularly at the shaft of the endotracheal tube being studied, and its output was continued until a blowtorch fire occurred or 60 seconds had elapsed. Sixty seconds of CO2 laser fire did not ignite any of the eight Laser-Trach endotracheal tubes tested. However, blowtorch ignition of all eight bare rubber tubes tested occurred after 0.87 +/- 0.21 (mean +/- SD) seconds of CO2 laser fire. Nd-YAG laser contact with the Laser-Trach endotracheal tubes caused the perforation and blowtorch ignition of all eight tubes tested after 18.79 +/- 7.83 seconds. This was a significantly (P<.05) longer time than the 5.45 +/- 4.75 seconds required for the blowtorch ignition of all eight plain rubber endotracheal tubes tested with the Nd-YAG laser. Our results show that under the conditions of this study, the shafts of the Kendall-Sheridan Laser-Trach endotracheal tubes were resistant to the C02 laser. However, this endotracheal tube is not recommended for use with the Nd-YAG laser.

Fire risk during laser airway surgery is well-documented, but there is limited information regarding this risk with the novel TruBlue laser. This study evaluates its safety under different experimental conditions. Using a cadaveric porcine larynx and lungs model, we conducted trials with laser-safe endotracheal tubes (LSETTs), high-flow ventilation (HFV), and jet ventilation. We varied distance, FiO2 levels, and laser power settings to observe the occurrence of uncontrolled fires, brief flames, and sparks. LSETT trials showed no fire events. Pledget fires were the only uncontrolled fires in HFV, at 100%, 70%, and 50% FiO2. Brief flames occurred only with 4 W continuous settings at 100% FiO2. Innocuous spark ignition rates were significantly increased by increased wattage (p < 0.05). In jet ventilation trials, brief flames appeared across a wider range of FiO2 levels and settings. HFV and jet ventilation groups showed a greater frequency and earlier occurrence of sparks and brief flames, in contrast to the event-free LSETT group (p < 0.05). Using the TruBlue laser with a fully inflated LSETT cuff positioned at least 0.3 cm below the operating area while delivering 100% oxygen was consistently safe in our trials. Uncontrolled fires occurred only when targeting a pledget under HFV, confirming extrinsic fuel as the main risk and highlighting the safety of the TruBlue laser with HFV and jet ventilation in its absence. Compared to HFV, jet ventilation trials showed a higher frequency of brief flames and sparks. A 60-s continuous application of the laser at 100% FiO2 is safe. NA.

We wish to report a case of unexpected difficult intubation after induction of anaesthesia caused by a tracheal ring. A 58-year-old woman, ASA III, was admitted for hysterectomy and bilateral salpingo-oophorectomy because of endometrial adenocarcinoma. Medical history revealed morbid obesity, noninsulin-dependent diabetes mellitus, hypertension and chronic asthmatic bronchitis treated with β2-adrenergic agonists, methylxanthines and oxygen therapy. Pulmonary function testing revealed an FEV1 of 38%, arterial blood gases confirmed hypoxaemia (Pao2 = 51 mmHg) and slight hypercapnia (Paco2 = 43 mmHg). Past surgical history included a laparotomy under general anaesthesia requiring some days in ICU because of her morbid obesity. Difficulty of tracheal intubation was suspected because of obesity and inadequate neck extension; after topical anaesthesia, vocal cords were clearly seen at laryngoscopy. General anaesthesia was induced and vecuronium 12 mg was given to facilitate tracheal intubation. A 7.5-mm i.d. tracheal tube could not be advanced beyond the vocal cords because of resistance. Intubation was reattempted with smaller tubes; finally, a 5.0-mm i.d. tube was passed through the vocal cords but adequate ventilation could not be maintained. The patient's trachea was extubated and normal emergence from anaesthesia occurred. Because of the unexpected difficulties in intubation an otolaryngologist was consulted in the operating theatre to examine the larynx and trachea. A tracheal ring was found which caused subglottic stenosis. Because of morbid obesity the patient was observed overnight in ICU. In the following days, following tracheostomy under local anaesthesia, general anaesthesia was induced and laser airway surgery was performed. Her tracheostomy was maintained to allow a hysterectomy and bilateral salpingo-oophorectomy to be carried out. Some weeks later the tracheostomy tube was removed, her flow volume loop improved and oxygen therapy was discontinued. Our case of difficult intubation was unexpected even though a difficult laryngoscopy was anticipated for morbid obesity and inadequate neck extension; after induction of general anaesthesia, a tracheal ring created an obstacle to tracheal intubation and only a very small tracheal tube could be passed (5.0-mm i.d. tube), which proved inadequate for ventilation. A tracheal ring consists of a congenital or acquired, fibrous membrane. An acquired ring may develop as a result of injury to the tracheal mucous membrane and submucosal tissues primarily due to iatrogenic intervention, especially long-term intubation [1–3]. Postoperative review of the patient's history revealed worsening of dyspnoea following her previous laparotomy. Her postoperative period of ventilation in ICU for morbid obesity probably caused scaring, which resulted in an acquired tracheal ring. However, her increasing tracheal stenosis was confused with worsening of chronic bronchitis. In this case a tracheal ring was an unsuspected and coincidental finding but caused an obstacle to tracheal intubation [1–3]. The absence of symptoms such as stridor or sign of upper airways obstruction, in spite of a marked decrease in tracheal cross-section, is consistent with the observation that symptoms rarely occur until at least 75% of the tracheal diameter has been obliterated [3]; in this case exertional dyspnoea was attributed to worsening of chronic bronchitis.

Con: Bronchial stenting and laser airway surgery should not take place outside the operating room

The use of the laser in surgery has led to a resurgence of an old problem that had been considered eliminated: the danger of fires and explosions. Anesthesiologists remember very well the fires and explosions that occurred when combustible anesthetics such as ether were used. Now we are finding however, that when using the laser, a medium that has a high energy density and collimation, that we are seeing a resurgence of such fires. In anesthesiology, we have a special problem regarding combustion because of the proximity of the laser to the endotracheal tube during laser airway surgery.The use of the laser in surgery has led to a resurgence of an old problem that had been considered eliminated: the danger of fires and explosions. Anesthesiologists remember very well the fires and explosions that occurred when combustible anesthetics such as ether were used. Now we are finding however, that when using the laser, a medium that has a high energy density and collimation, that we are seeing a resurgence of such fires. In anesthesiology, we have a special problem regarding combustion because of the proximity of the laser to the endotracheal tube during laser airway surgery.

IntroductionThis article presents our experience with an alternative cannulation strategy for VV ECMO, adding it to previously reported cases found on PubMed.Case reportWe report three cases: two patients aged 17 and one aged 3. Two required VV ECMO for pneumonia, and one for airway surgery. All patients had a two-site approach. In two cases, drainage was initiated from the left side of the neck at the onset of therapy, with return to the groin. One patient required a change in the drainage cannula from the right to the left side during treatment, while the return continued to the groin.DiscussionMany centres have reported positive outcomes with alternative sites for cannulation in adults, including the left side of the neck. Alternative sites for cannulation require proper visualization techniques for guidewire and cannula insertion due to possible complications. We share our positive experience with left-sided cannulation using transthoracic echocardiographic visualization and a supraclavicular approach in paediatric patients of various weights.ConclusionLeft-sided cannulation is a safe option in specific clinical cases. Further studies are needed to validate this approach, especially for paediatric patients.

Transoral laser surgery for glottic stenosis (transverse cordotomy and anteromedial arytenoidectomy (TCAMA)) is often complicated by granulation tissue (GT) formation. GT can cause dyspnea and may require surgical removal to alleviate airway obstruction. Inhaled corticosteroids (ICS) have been shown to reduce benign vocal fold granulomas, however its use to prevent GT formation has not been described. We aimed to analyze the effect of immediate postoperative ICS on GT formation in patients undergoing transoral laser surgery for glottic stenosis. A retrospective analysis of patients that had transoral laser surgery for glottic stenosis from 2000 to 2019 was conducted. Surgical instances were grouped into those that received postoperative ICS and those that did not. Demographics, diagnosis, comorbidities, intraoperative adjuvant therapy, and perioperative medications were collected. Differences in GT formation and need for surgical removal were compared between groups. A multivariate exact logistic regression model was performed. Forty-four patients were included; 16 required 2 glottic airway surgeries (60 surgical instances). Of the 23 instances where patients received immediate postoperative ICS, 0 patients developed GT; and of the 37 instances that did not receive postoperative ICS, 15 (40.5%) developed GT (P < .0001). Eight (53.3%) of these cases returned to the OR for GT removal. ICS use was solely associated with the absence of GT formation (P = .042) in the multivariate analysis. Immediate postoperative use of ICS seems to be a safe and effective method to prevent granulation tissue formation and subsequent surgery in patients following transoral laser airway surgery for glottic stenosis.

The changing face of paediatric airway endoscopic surgery: An 8-year single surgeon review

Management of airway obstruction

This brief review of the anesthesiologist's role in the team effort necessary for the safe treatment of airway tumors by laser beam is provided to acquaint the referring physician or medical oncologist with some of the anesthesiologist's operating room concerns and how they are met. The necessity of bringing the patient to a level of maximum physiologic reserve prior to treatment becomes obvious with information gained by scanning this review. The referring physician or medical oncologist aids the patient and the anesthesiologist and surgeon by performing a thorough preoperative cardiopulmonary evaluation and therapeutic intervention, as indicated by patient need. The review includes a description of the actions of the carbon dioxide (CO2) and neodynium-yttrium aluminum garnet (YAG) lasers, "laser safety" for patients and personnel, monitoring, guarding the airway, ignition dangers, and comments on the use of jet and high frequency jet ventilation (HFJV).

The occurrence of airway fires during laser airway surgery necessitates the use of special techniques to improve patient safety. For example, it is recommended that the endotracheal tube cuff be inflated with saline. However, in the event of an endotracheal tube fire, the tube must be quickly removed. This study was designed to determine the time necessary for red rubber (RR) or polyvinylchloride (PVC) endotracheal tubes to be removed from a model airway after inflating the cuffs with saline. A model larynx and trachea was suspended vertically. It was intubated with either 7.0 RR or PVC endotracheal tubes. Six milliliters of saline was used to inflate the endotracheal tube cuffs. After inflation, a clamp was used to occlude the pilot tube on the RR endotracheal tubes. A 4-lb weight was then suspended from the endotracheal tube. The time to spontaneous extubation of the model trachea after unclamping the pilot tubes on 12 RR endotracheal tubes was determined. For the PVC endotracheal tubes, the times to spontaneous extubation using the 4-lb weight were determined in 12 endotracheal tubes after cutting the pilot tube and in 12 by maximum aspiration of the saline from the endotracheal tube cuff with a 10-ml syringe. A time of 0.94 +/- 0.10 sec (mean +/- SD) was required for spontaneous extubation of the RR endotracheal tubes after unclamping the pilot tube. For the PVC endotracheal tubes, extubation occurred 3.28 +/- 1.08 and 1.81 +/- 0.60 sec after cutting the pilot tube or deflating the cuff with a syringe, respectively. The mean times for each of the 3 groups were significantly different (p < 0.05) from each other as determined by the ANOVA. This study shows that if PVC endotracheal tubes are used, deflation of the saline-filled cuff by aspiration with a 10-ml syringe is faster than cutting the pilot tube. Unclamping the pilot tube on the RR endotracheal tubes resulted in the fastest time to endotracheal extubation.

To determine whether the filling of tracheal tube cuffs with saline would decrease their combustibility during laser surgery, 20 polyvinylchloride tracheal tubes were studied. The cuffed end of each tracheal tube was inserted into the neck of an empty flask, and the tube and flask were flushed with oxygen for 5 min before cuff inflation. Ten tracheal tubes had their cuffs inflated with air, and 10 were inflated with saline. A Lasersonics LS880 CO2 laser, set to 5 W for five of each of the two types of filled cuffs and to 40 W for the other pair of five tubes, was fired continuously at the cuffs for up to 1 min. No combustion occurred at the 5-W setting. The times to cuff perforation when the laser was set at 5 W were (mean +/- SD) 1.00 +/- 0.83 and 4.21 +/- 3.91 s for the air- and saline-filled cuffs, respectively, a difference that was not statistically significant. The time to deflation of the saline-filled cuff (104.6 +/- 67.5 s) was, however, significantly longer than that of the air-filled cuff (2.59 +/- 1.97 s). When the tracheal tube cuffs were exposed to 40-W laser radiation, the cuff and adjacent tube shaft ignited in all cases when the cuffs were inflated with air, but only in one of five cases when the cuffs were filled with saline (P less than 0.05). The filling of tracheal tube cuffs with saline provides simple, moderately effective partial protection of the cuff of endotracheal tubes during CO2 laser airway surgery.