Polyvinyl Chloride Endotracheal Tube Research Articles

Ease of endotracheal intubation with the conventional polyvinyl chloride endotracheal tube versus wire-reinforced flexometallic tube through the intubating laryngeal mask airway: A comparative study.

The aim of our study was to compare the ease of intubation when using conventional PVC tubes versus the wire-reinforced flexometallic tubes with the ILMA-FastrachTM. The number of attempts, time taken and additional maneuvers were noted. Intra-operative hemodynamic changes, post-operative sore throat, bleeding and hoarseness of voice was recorded over a period of 24 hours. After informed consent, 60 ASA I-II patients undergoing elective surgeries under general anesthesia were allocated to undergo blind intubation with the PVC tube or the wire-reinforced flexometallic tube. More attempts were required for successful intubation using the wire-reinforced tube than the PVC tube with 76.7% passing in the first attempt in the PVC, and 53.3% passing in the first attempt in the flexometallic group. (P = 0.4). Average time for intubation in the PVC group: 28.24 ± 7.22 seconds. Average time for intubation in the flexometallic tube: 45.8 ± 15.78 sec. Occurrence of post-operative sore throat was 13.3% in the PVC group and 26.6% in the flexometallic group, with minimal hoarseness of voice 3.3% in the PVC group and 10% in the flexometallic group. There was also a slightly higher hemodynamic response in those who were intubated with the flexometallic tube than a PVC tube. Intubating via the ILMA-Fastrach with the PVC tube offered better intubating conditions with regards to lesser time taken, lesser attempts, less manipulation, and less hemodynamic variations as compared to the patients who were intubated using the wire-reinforced tube.

Comparison between Polyvinyl Chloride and Flexometallic Endotracheal Tube for Blind Tracheal Intubation through I-gel: A Randomised Clinical Study

Introduction: I-gel is the most commonly used, secondgeneration supraglottic airway device, which plays an important role in modern anaesthesia practice as a rescue device in difficult as well as failed intubation situations and resuscitations. Now-a-days, it is gaining popularity as a conduit to facilitate endotracheal intubation. No Endotracheal Tube (ETT) is designed specifically for intubation through I-gel. The ETT used for routine tracheal intubation are standard Polyvinyl Chloride (PVC) ETT and Flexometalic ETT. Aim: To compare the two different types of ETTs i.e. standard PVC ETT and Flexometatlic ETT for blind tracheal intubation through I-gel. Materials and Methods: The present study was a singleblinded, randomised clinical trial in which 120 patients were randomly allocated into two groups on the basis of the ETT used for intubation through I-gel. In Group P blind tracheal intubation was done using PVC ETT, and in Group F blind tracheal intubation was done using Flexometatlic ETT through I-gel. Time taken for successful intubation, number of successful intubations, ease of intubation, number of attempts,manoeuvers used, and complications were recorded. Results: The mean time taken for successful intubation in Group P was 22.31±3.771 sec and in Group F was 26.51±4.408 sec (p<0.05). Intubation was significantly easy (26/60 vs 13/60) with PVC ETT (p=0.011). More patients were successfully intubated with PVC ETT than Flexometalic ETT (48/60 vs 36/60; p=0.017). Conclusion: PVC ETT is a better choice for blind tracheal intubation through I-gel as compared to flexometallic ETT.

Anaesthetic Challenges in a Paediatric Patient with Escobar Syndrome-Difficult Airway and Postoperative Pneumothorax.

Escobar syndrome (ES) is an autosomal recessive disorder characterised by the presence of pterygia in cervical, antecubital and popliteal regions. Anaesthesiologist encounter notable challenges in this syndrome, especially airway management due to associated malformations like cleft lip/palate, micrognathia, syngnathia, ankyloglossia, neck contracture, cervical spine fusion, limited neck extension and craniofacial dysmorphism. In addition to difficult airway, anaesthesiologist may encounter other perioperative challenges. Here, we report a paediatric patient with ES, who required general anaesthesia for laparoscopic inguinal hernia repair and orchidopexy. Initial attempt with video laryngoscope failed due to inability to visualise epiglottis. Subsequent attempt with fibreoptic bronchoscope also failed due to rapid decrease in oxygen saturation. He was finally intubated with fibreoptic bronchoscope along with oxygen insufflation with a 3mm internal diameter polyvinylchloride endotracheal tube inserted nasally and connected to oxygen supply. Further perioperative challenges faced were intraoperative hyperthermia and postoperative pneumothorax with mediastinal shift. To the best of our knowledge, this is the first case reporting pneumothorax with mediastinal shift as a postoperative complication and use of oxygen insufflation through nasal tube during fibreoptic intubation in paediatric patient with ES.

Evaluation of audible leak versus pressure volume loop closure for polyvinyl chloride cuff and polyurethane microcuff in endotracheal tube inflated with air: a prospective randomized study.

Cuff pressure of endotracheal tube (ETT) must be high enough to seal the trachea, and must be low enough to allow adequate perfusion of tracheal mucosa. Compared with polyvinyl chloride (PVC) cuffed tubes, polyurethane cuffed tubes protect more efficiently. Different methods of ETT cuff pressure maintenance in practice have been reported. We planned to compare ETT cuff pressure using different techniques in PVC and polyurethane microcuff tubes in a prospective randomized study. Eighty surgical patients between 16–65 years belonging to American Society of Anesthesiologists physical status I–III, scheduled for orotracheal intubation under general anaesthesia, were included. All enrolled patients were randomized into four groups (n = 20 per group), followed by corresponding treatments, including intubation by PVC ETT or polyurethane microcuff ETT and cuff inflation by auscultation of audible leak or pressure volume loop. Amount of air required to inflate cuff was more in polyurethrane tube as compared to polyvinyl tube. While comparing the two methods of cuff inflation, less volume of air was required in pressure volume loop method. We concluded that PVC cuff tube and polyurethane microcuff tube both are safe tubes used in adult patients. However, when inflated using same technique polyurethane microcuff tubes required larger volume to inflate cuff. Further, pressure generated in polyurethane microcuff tubes in much lower than PVC tubes. The study was approved by the Institutional Ethics Committee of Pt B D Sharma, PGIMS, Rohtak (No. IEC/Th/18/Anst15) on January 20, 2018 and registered with Clinical Trials Registry-India (registration No. CTRI/2019/01/017170) on January 18, 2019.

Biofilm formation on three different endotracheal tubes: a prospective clinical trial

BackgroundBiofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation.MethodsWe compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP.ResultsHigh-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14–15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06–0.59], p = 0.005, and OR 0.34 [95% CI 0.13–0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17–1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation.ConclusionHigh-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed.Trial registrationClinicalTrials.gov NCT02284438. Retrospectively registered on 21 October 2014.

Influence of Fitness-empowering Elderly Intervention Programs on Fitness Levels in Semarang City, Indonesia

Armoured endotracheal tube is commonly used during neurosurgical procedures for airway secure. In intensive care unit, the major complications reported with the use of armoured endotracheal tube are related to patient's biting on the tube. In the present cases, we described the armoured endotracheal tube was obstructed by patient biting of the tube. From this report, we learned that adequate sedation and oral airway securer are necessary to protect the armoured endotracheal tube. Moreover, a nasal or oral polyvinylchloride endotracheal tube or tracheostomy may be a better substitution for long-term artificial airway use.

Airway management for tracheal resection proximal to carina in a cat

Tracheal tumours in cats are rare, and most primary tumours respond well to complete surgical excision. Providing secure airway management during resection of the trachea is particularly challenging and in...

Anesthesia-related Safety Profile of a High-energy Ultrasonic Scalpel in Oropharyngeal and Laryngeal Surgery: An Ex Vivo Model.

IntroductionThe aim of this study was to evaluate the fire risks associated with a harmonic scalpel, with an established avian model simulating oropharyngeal/laryngeal surgery. MethodsA standard polyvinyl-chloride (PVC) endotracheal tube (ETT) was inserted into a degutted, whole raw chicken through which 100% oxygen was piped at 10 L/min. The inflated cuff of the tube was grasped and sectioned with the jaws of a standard high-power ultrasonic dissection system Ultracision (Ethicon Endosurgery, Cincinnati, Ohio, USA). Then, the whole ETT was grasped and cut, leaving the device in contact with the ETT for two more minutes. In a second step under the same conditions, an electrosurgical device was placed into the chicken cavity and activated at the chicken tissue near the ETT at a setting of 20 W. All trials were repeated to ensure accuracy.ResultsNo ignition could be produced with the harmonic scalpel under any operation mode settings. In all cases, the ETT was cut through with some fumes and brown discoloration at the site of contact. The electrosurgical device easily caused flash ignition within seconds.ConclusionThe harmonic scalpel appears to be a safer tool than electrosurgical devices in the setting of open cavity surgery in oxygen-enriched environments with respect to the presence of flammable medical PVC devices as ETT or catheters.

I-Gel as an intubation conduit: Comparison of three different types of endotracheal tubes.

Background and Aims:I-Gel®, a novel SAD has been introduced as a ventilating device but has widely gained popularity as conduit for intubation. Unlike intubating laryngeal mask airway (ILMA), I-Gel® does not have an endotracheal tube specially designed for it. Hence the aim of this study was to compare the rate of successful intubation via I-Gel® using three different types of endotracheal tubes.Methods:We randomised 75 American Society of Anesthesiologists (ASA) physical status I and II patients, between the age group 18-60 years of either sex undergoing elective surgery under general anaesthesia into three groups on the basis of endotracheal tube (ETT), used for intubation via I-Gel®: Group P (Polyvinyl chloride ETT), Group I (Intubating laryngeal mask airway ETT), Group F (flexometallic ETT). After following the standard induction protocol, appropriate size I Gel® was inserted in all patients. Thereafter group specific ETT was inserted via I-Gel®. We recorded and compared the time taken for successful intubation, the success rate, number of attempts taken, manoeuvres used, and complications among three different types of ETT. Quantitative variables were compared using Kruskal Wallis test and the qualitative variables were compared using Chi-square test.Results:The time taken for successful intubation was least in group P (10.51 ± 3.82 seconds). Group P also had the highest first attempt (68%) and overall rate of successful intubation (88%).Conclusion:PVC ETT had highest first attempt success rate and required minimum time for endotracheal intubation via I-Gel® when compared to ILMA ETT and Flexible ETT.

Modification of Tracheal Cuff Shape and Continuous Cuff Pressure Control to Prevent Microaspiration in an Ex Vivo Pig Tracheal Two-Lung Model.

Microaspiration of subglottic secretions plays a pivotal role in ventilator-associated pneumonia. Impact of endotracheal tube cuff material and shape on tracheal sealing performance remains debated. The primary objective was to compare the tracheal sealing performance of polyvinyl chloride tapered, cylindrical and spherical cuffs. Secondary objectives were to determine the impact of continuous cuff pressure control on sealing performance and pressure variability. Prospective randomized ex vivo animal study. French research laboratory. Seventy-two ex vivo pig tracheal two-lung blocks. Blocks were randomly intubated with cylindrical (n = 26), tapered (n = 24), or spherical (n = 22) polyvinyl chloride endotracheal tube cuffs. Two milliliter of methylene blue were instilled above the cuff to quantify microaspirations, and lungs were ventilated for 2 hours. Continuous cuff pressure control was implemented in 33 blocks. Cuff pressures were continuously recorded, and after 2 hours, a microaspiration score was calculated. Tapered cuffs improved cuff sealing performance compared with spherical cuffs with or without continuous cuff pressure control. Compared with spherical cuffs, tapered cuffs reduced the microaspiration score without and with continuous pressure control by 65% and 72%, respectively. Continuous cuff pressure control did not impact sealing performance. Tapered cuffs generated higher cuff pressures and increased the time spent with overinflation compared with spherical cuffs (median [interquartile range], 77.9% [0-99.8] vs. 0% [0-0.5]; p = 0.03). Continuous cuff pressure control reduced the variability of tapered and spherical cuffs likewise the time spent with overinflation of tapered and cylindrical cuffs. Polyvinyl chloride tapered cuffs sealing enhanced performance at the cost of an increase in cuff pressure and in time spent with overinflation. Continuous cuff pressure control reduced the variability and normalized cuff pressures without impacting sealing performance.

Lipase degradation of plasticized polyvinyl chloride endotracheal tube surfaces to create nanoscale features.

Polyvinyl chloride (PVC) endotracheal tubes (ETTs) nanoetched with a fungal lipase have been shown to reduce bacterial growth and biofilm formation and could be an inexpensive solution to the complex problem of ventilator-associated pneumonia (VAP). Although bacterial growth and colonization on these nanoetched materials have been well characterized, little is known about the mechanism by which the fungal lipase degrades the PVC and, thus, alters its properties to minimize bacteria functions. This study used X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to better describe the surface chemistry of both unetched and lipase nanoetched PVC ETT. ATR-FTIR analysis of the unetched and treated surfaces showed a similar presence of a plasticizer. This was confirmed by XPS analysis, which showed an increase of carbon and the presence of oxygen on both unetched and nanoetched surfaces. A quantitative comparison of the FTIR spectra revealed significant correlations (Pearson’s correlation, R=0.997 [R2=0.994, P<0.001]) between the unetched and nanomodified PVC ETT spectra, demonstrating similar surface chemistry. This analysis showed no shifting or widening of the bands in the spectra and no significant changes in the intensity of the infrared peaks due to the degradation of the plasticizer by the fungal lipase. In contrast, results from this study did demonstrate significantly increased nanoscale surface features on the lipase etched compared to non-etched PVC ETTs. This led to a change in surface energetics, which altered ion adsorption to the ETTs. Thus, these results showed that PVC surfaces nanoetched with a 0.1% lipase solution for 48 hours have no significant change on surface chemistry but do significantly increase nanoscale surface roughness and alters ion adsorption, which suggests that the unique properties of these materials, including their previously reported ability to decrease bacterial adhesion and growth, are due to the changes in the degree of the nanoscale roughness, not changes in their surface chemistry.

Decreased Pseudomonas aeruginosa biofilm formation on nanomodified endotracheal tubes: a dynamic lung model.

Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation that has been shown to be associated with increased mortality rates and medical costs in the pediatric intensive care unit. Currently, there is no cost-effective solution to the problems posed by VAP. Endotracheal tubes (ETTs) that are resistant to bacterial colonization and that inhibit biofilm formation could provide a novel solution to the problems posed by VAP. The objective of this in vitro study was to evaluate differences in the growth of Pseudomonas aeruginosa on unmodified polyvinyl chloride (PVC) ETTs and on ETTs etched with a fungal lipase, Rhizopus arrhizus, to create nanoscale surface features. These differences were evaluated using an in vitro model of the pediatric airway to simulate a ventilated patient in the pediatric intensive care unit. Each experiment was run for 24 hours and was supported by computational models of the ETT. Dynamic conditions within the ETT had an impact on the location of bacterial growth within the tube. These conditions also quantitatively affected bacterial growth especially within the areas of tube curvature. Most importantly, experiments in the in vitro model revealed a 2.7 log reduction in the number (colony forming units/mL) of P. aeruginosa on the nanoroughened ETTs compared to the untreated PVC ETTs after 24 hours. This reduction in total colony forming units/mL along the x-axis of the tube was similar to previous studies completed for Staphylococcus aureus. Thus, this dynamic study showed that lipase etching can create surface features of nanoscale roughness on PVC ETTs that decrease bacterial attachment of P. aeruginosa without the use of antibiotics and may provide clinicians with an effective and inexpensive tool to combat VAP.

Evaluation of the Effect of Tracheal Tube Orientation on Success of Intubation through Intubating Laryngeal Mask Airway.

Polyvinyl Chloride Endotracheal Tube (PVC ETT) can be used as an alternative to Fastrach Silicone Wire-Reinforced Tube (FTST) for intubation through Intubating Laryngeal Mask Airway (ILMA) as the latter is expensive and has low volume high pressure cuff. To evaluate the effects of orientation of PVC ETT (normal curve and reverse curve) on the success of intubation through ILMA, haemodynamic response and postoperative sore throat. Sixty healthy adult patients of ASA physical status I & II scheduled for elective surgery under general anaesthesia requiring endotracheal intubation were randomly divided into two groups. In Normal (N) group (n=30), the tracheal tube was inserted with its natural curve following the 90° curvature of ILMA. In Reverse (R) group (n=30), the tracheal tube was inserted with its natural curve directed opposite to the curvature of ILMA. The time taken to intubate, number of attempts, and maneuvers required for successful endotracheal intubation along with haemodynamics and oxygen saturation were noted. Postoperative sore throat was evaluated using a Verbal Analogue Scale (VAS) (0-10). Qualitative data was analysed by Chi-Square test and Fisher's exact test. Quantitative data was analysed by unpaired t-test and Mann-Whitney test. Placement of ILMA was successful in all patients. Total Intubation Time (mean±SD) in Group N was 12.53±1.78 seconds and in Group R was 11.97±1.33 seconds (p>0.05). Tracheal intubation through ILMA was successful in all patients. First attempt success rate in R Group (26 patients, 86.7%) was higher than N Group (22 patients, 73.3%) (p>0.05). Four patients (13.3%) in R Group and 8 patients (26.7%) in N Group required 2nd step of Chandy's maneuver during second attempt for successful intubation. Incidence of sore throat 6 hours postoperatively was statistically significant (median value 2.00 in N Group vs. 0.00 in R Group) between two groups. PVC ETT with reverse orientation increases first attempt success rate of intubation through ILMA with less immediate postoperative laryngeal morbidity.

Activities of tobramycin and polymyxin E against Pseudomonas aeruginosa biofilm-coated medical grade endotracheal tubes.

Indwelling medical devices have become a major source of nosocomial infections, especially Pseudomonas aeruginosa infections, which remain the most common cause of ventilator-associated pneumonia (VAP) in neonates and children. Using medical grade polyvinyl chloride endotracheal tubes (ETTs), the activity of tobramycin and polymyxin E was quantified in a simulated prevention and treatment static time-kill model using biofilm-forming P. aeruginosa. The model simulated three clinical conditions: (i) planktonic bacteria grown in the presence of antibiotics (tobramycin and polymyxin E) without ETTs, (ii) planktonic bacteria grown in the presence of P. aeruginosa, antibiotic, and ETTs (simulating prevention), and (iii) a 24-h-formed P. aeruginosa biofilm grown on ETTs prior to antibiotic exposure (simulating treatment). In the model simulating "prevention" (conditions 1 and 2 above), tobramycin alone or in combination with polymyxin E was more bactericidal than polymyxin E alone at 24 h using a concentration of greater than 2 times the MIC. However, after a 24-h-old biofilm was allowed to form on the ETTs, neither monotherapy nor combination therapy over 24 h exhibited bactericidal or bacteriostatic effects. Against the same pathogens, tobramycin and polymyxin E, alone or in combination, exhibited bactericidal activity prior to biofilm attachment to the ETTs; however, no activity was observed once biofilm formed on ETTs. These findings support surveillance culturing to identify pathogens for a rapid and targeted approach to therapy, especially when P. aeruginosa is a potential pathogen.

Evaluating the Effects of a 532‐nm Fiber‐Based KTP Laser on Transoral Laser Surgery Supplies

The KTP laser has become commonplace in transoral head and neck surgery. The interactions of this laser with commonly used supplies in transoral surgery have not been formally examined. This study evaluates the effects of the KTP laser on surgical supplies. Experimental study. The study was conducted in an empty operating room at a university-affiliated medical center. An Aura XP 532-nm KTP laser with a 600-nm fiber was used in pulsed and continuous modes. The beam was focused at the shaft and balloon of 3 "laser-safe" endotracheal tubes (ETTs), a polyvinyl chloride (PVC) ETT, and a Codman surgical patty. Time to penetrate was recorded. Results The KTP laser beam was unable to penetrate any of the laser-resistant ETTs. It did react with the black number markings on the PVC ETT by producing sparks but was unable to penetrate the shaft of the ETT. The KTP laser was nonreactive with all ETT cuffs except in 1 of 3 trials with the outer balloon cuff of a Rusch Lasertubus ETT when the laser was used in a continuous mode. The KTP laser caused the production of a flame upon contact with the blue radiopaque strip of the surgical patty, even when the patty was wet. This study demonstrates that a number of safe ETT options may be used during transoral laser microsurgery with a KTP laser. In addition, Codman surgical patties are shown to be a significant fire risk in KTP laser surgery.

Laryngeal surgery using a CO2 laser: is a polyvinylchloride endotracheal tube safe?

ObjectiveWe performed retrospective clinical analysis and in vitro testing to analyze the risks involved in laryngeal surgery using a CO2 laser. Materials and methodsThe occurrence of adverse events during laryngeal surgeries using a CO2 laser, the reasons for these adverse events, and the risks of laryngeal laser surgery were analyzed in 704 patients. In vitro experiments were performed to observe the tolerance of the cuffs of polyvinylchloride (PVC) endotracheal tubes to the CO2 laser under conditions of filling water or air, different laser power levels, and different cutting patterns. The flammability of the PVC endotracheal tube under different oxygen concentrations, laser power levels, and laser cutting patterns were also studied. ResultsIn the 704 patients who underwent laryngeal laser surgery, the tracheal cuff broke in 92 cases; sparks were observed in 8 cases; and dense smoke, in 27 cases during surgery. No fires or explosions occurred. The in vitro results were as follows: (1) Under the intermittent stimulation mode, the water cuff did not break, but the air cuff broke during the first stimulation. (2) Under the continuous stimulation mode, the water and air cuffs broke easily, and the water and air cuffs broke immediately when the stimulation power was greater than 8 W. (3) Under the intermittent stimulation mode, the PVC endotracheal tube burned only under conditions of pure oxygen supply and 10 W of laser power. Under the continuous stimulation mode, the tube did not burn with 5 W of laser power, regardless of the oxygen concentration used. When the laser power level reached 8 W and the oxygen concentration was greater than 50%, the tube will easily burn. When the laser power level was 10 W, the tube burned at oxygen concentrations greater than 20%. ConclusionsBurning of the tube during laryngeal surgery using a CO2 laser could be effectively avoided when appropriate measures were taken, such as filling the endotracheal cuff with water, maintaining less than 40% oxygen concentration, using less than 8 W laser power, and using the intermittent stimulation mode.

Stylet-Assisted Tracheal Intubation Through an ILMA in a Patient with an Anterior Larynx

To the Editor Although the intubating laryngeal mask airway (ILMA) has been described for use in morbidly obese patients,1 despite its correct placement, tracheal intubation may be unsuccessful. An obese male patient (body mass index [BMI] = 34) in the intensive care unit with a right middle cerebral artery territory stroke required urgent tracheal intubation owing to poor Glasgow coma scale (E1V1M2). After sedation and paralysis, ventilation via a mask was adequate but intubation using a #4 Macintosh blade, external laryngeal manipulation, and a bougie was not possible. An ILMA (#4 LMA-Fastrach™, The Laryngeal Mask Company Limited, Le Rocher, Victoria, Mahé, Seychelles) was placed and ventilation resumed. Tracheal intubation using the flexometallic tube provided with the ILMA failed as the tube tip was repeatedly displaced into the esophagus. Repositioning of the ILMA and Chandy's maneuver part 22 were attempted but also unsuccessful. Intubation with a 7.0-mm internal diameter cuffed Portex polyvinyl chloride (PVC) endotracheal tube (ETT) (Smiths Medical, UK), together with a flexion maneuver, also did not help because of the anteriorly positioned larynx. Size 5 ILMA and Fiberoptic Bronchoscope were unavailable. Hence, using a stylet, the tip of the portex tube was bent as shown in Figure 1 and reintroduced through ILMA, and the ETT could be easily advanced off the stylet into the trachea.Figure 1: Angle of emergence formed by the tracheal tubes on emerging from the distal aperture of the intubating laryngeal mask airway (ILMA). A, LMA-Fastrach silicone wire-reinforced tube (7.5-mm internal diameter). B, Portex polyvinyl chloride tracheal tube (7.5-mm internal diameter). C, Portex polyvinyl chloride tracheal tube with stylet (PVCT; 7.5-mm internal diameter).In cases of extremely anterior larynx, accentuating the angle of emergence of the tracheal tube from the ILMA may facilitate intubation.3 This may be safely done by ensuring that the tip of the stylet remains within the ETT, about 1 to 2 cm proximal to the tip of ETT. We measured the angle of emergence (using a protractor) of Flexometallic and Portex PVC ETT through ILMA and found them to be 35° and 45°, respectively (Fig. 1A & 1B). Introducing a stylette as suggested increases the angle of emergence to 65° (Fig. 1C), which aids in placement of the tracheal tube tip through ILMA in patients with anterior larynx. Damage to the arytenoids and trachea is a potential complication of blind intubation. Difficulty in advancing the tube due to impingement upon the anterior surface of the larynx is another possibility. Using the Parker flexitip PVC tube is an option in this scenario. The centered, tapered, and flexible distal tip gently flexes when resistance is encountered, thus enabling successful introduction minimizing airway trauma.4 Patient consent statement Written permission from the patient's first degree relative was obtained because the patient passed away at home owing to unrelated causes, months after treatment, prior to this submission. The written consent statement is available from the archival author. Georgene Singh, MD Appavoo Arulvelan, MD Kadarapura N. Gopalakrishna, MD Sethuraman Manikandan, MD Vimala Smita, MD, DM Ramesh C. Rathod, MD Department of Anesthesiology Sree Chitra Tirunal Institute for Medical Sciences and Technology Thiruvananthapuram Kerala, South India [email protected]

Decreased Staphylococcus aureus biofilm formation on nanomodified endotracheal tubes: a dynamic airway model

Ventilator-associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation for over 24 hours increases the risk of VAP and is associated with high morbidity, mortality, and medical costs. Cost-effective endotracheal tubes (ETTs) that are resistant to bacterial infections could help prevent this problem. The objective of this study was to determine differences in the growth of Staphylococcus aureus on nanomodified and unmodified polyvinyl chloride (PVC) ETTs under dynamic airway conditions simulating a ventilated patient. PVC ETTs were modified to have nanometer surface features by soaking them in Rhizopus arrhisus, a fungal lipase. Twenty-four-hour experiments (supported by computational models) showed that airflow conditions within the ETT influenced both the location and the concentration of bacterial growth on the ETTs, especially within areas of tube curvature. More importantly, experiments revealed a 1.5 log reduction in the total number of S. aureus on the novel nanomodified ETTs compared with the conventional ETTs after 24 hours of airflow. This dynamic study showed that lipase etching can create nanorough surface features on PVC ETTs that suppress S. aureus growth, and thus may provide clinicians with an effective and inexpensive tool to combat VAP.

An unusual site of an occult air leak in an armoured endotracheal tube in the midst of surgery

Sir, Even after a recommended check of the anaesthesia equipments, we may sometimes face some intriguing problems during the surgical interventions. We describe an unusual site of an air leak in an armoured endotracheal tube (ETT) in the midst of the surgical procedure involving the trachea. A 35-year-old male, ASA class 1 patient with a history of tracheal injury was posted for Montgomery T-tube insertion through the tracheostomy site. After administration of general anaesthesia, the tracheostomy tube was removed and the patient was intubated with a 38FG Rusch® armoured ETT through the tracheostomy site. Before insertion, a recommended check of cuff and cuff inflation assembly was performed, with no leaks detected.[12] Instead of using an adhesive tape for securing the ETT in place, the surgeon insisted on application of a stay suture over the sternal skin and to tie it with the ETT. We noticed the leak pressure alarm displayed on the screen of the anaesthesia machine (GE Datex Ohmeda Aestiva 5®) nearly 20 min after the start of the surgical procedure. The surgeons also noticed the leak around the cuff and immediately alarmed us. The cuff was reinflated and surgery started, but again the same leak pressure alarm was displayed on the monitor after 10 min of the commencement of surgery. We decided to stop the surgery and replace the armoured ETT with fresh armoured ETT. Meanwhile, we carried out an in vitro check for patency of cuff, which showed no air leak, and, therefore, we decided to put whole tube in water to check the leak in the inflation tube assembly. To our surprise, we found a leak from the site where the surgeons had applied the stay suture near the 20 cm mark where the inflation tube was embedded in the ETT [Figure 1].Figure 1: Air leak site from the inflation tube assemblyWe concluded that applying a stay suture might have breached the integrity of the inflation tube that was embedded in the armoured ETT, leading to occult air leak. A similar observation with resterlized armoured ETT had been noted before when these tubes were stretched during the surgical procedure, allowing air to leak if any cuts or holes were present in the ETT, which usually get missed on routine check.[34] We observed that the inflation tube assembly of the armoured ETT is more superficially embedded in the wall of the ETT as compared with the poly vinyl chloride ETT; therefore, the chances of its damage are greater. The surgeons should be discouraged to apply stay suture on these ETTs for securing it in place. In certain situations, if the stay suture is necessary for securing the tube, then certain simple yet effective maneuvers can be done to avoid damage to the inflation tube assembly. The ETT should be placed in such a way that the tangential force of the stay suture should not directly be applied on the wall of the ETT where the inflation tube assembly is embedded. For that, the ETT with the inflation tube assembly should be facing downward and away from the contact point of the suture. If required, we can also apply a sterilized adhesive tape or an aluminium foil circumferentially in that area where the stay suture is tied onto the ETT, which will negate the effects of that tangential force and hence avoiding the breach in the inflation tube assembly.

Fructose-enhanced reduction of bacterial growth on nanorough surfaces

Patients on mechanical ventilators for extended periods of time often face the risk of developing ventilator-associated pneumonia. During the ventilation process, patients incapable of breathing are intubated with polyvinyl chloride (PVC) endotracheal tubes (ETTs). PVC ETTs provide surfaces where bacteria can attach and proliferate from the contaminated oropharyngeal space to the sterile bronchoalveolar area. To overcome this problem, ETTs can be coated with antimicrobial agents. However, such coatings may easily delaminate during use. Recently, it has been shown that changes in material topography at the nanometer level can provide antibacterial properties. In addition, some metabolites, such as fructose, have been found to increase the efficiency of antibiotics used to treat Staphylococcus aureus (S. aureus) infections. In this study, we combined the antibacterial effect of nanorough ETT topographies with sugar metabolites to decrease bacterial growth and biofilm formation on ETTs. We present for the first time that the presence of fructose on the nanorough surfaces decreases the number of planktonic S. aureus bacteria in the solution and biofilm formation on the surface after 24 hours. We thus envision that this method has the potential to impact the future of surface engineering of biomaterials leading to more successful clinical outcomes in terms of longer ETT lifetimes, minimized infections, and decreased antibiotic usage; all of which can decrease the presence of antibiotic resistant bacteria in the clinical setting.