Macintosh Laryngoscope Blade Research Articles

Effect of Use of a Bougie vs Endotracheal Tube and Stylet on First-Attempt Intubation Success Among Patients With Difficult Airways Undergoing Emergency Intubation

The tracheal tube introducer, known as the bougie, is typically used to aid tracheal intubation in poor laryngoscopic views or after intubation attempts fail. The effect of routine bougie use on first-attempt intubation success is unclear. To compare first attempt intubation success facilitated by the bougie vs the endotracheal tube + stylet. The Bougie Use in Emergency Airway Management (BEAM) trial was a randomized clinical trial conducted from September 2016 through August 2017 in the emergency department at Hennepin County Medical Center, an urban, academic department in Minneapolis, Minnesota, where emergency physicians perform all endotracheal intubations. Included patients were 18 years and older who were consecutively admitted to the emergency department and underwent emergency orotracheal intubation with a Macintosh laryngoscope blade for respiratory arrest, difficulty breathing, or airway protection. Patients were randomly assigned to undergo the initial intubation attempt facilitated by bougie (n = 381) or endotracheal tube + stylet (n = 376). The primary outcome was first-attempt intubation success in patients with at least 1 difficult airway characteristic (body fluids obscuring the laryngeal view, airway obstruction or edema, obesity, short neck, small mandible, large tongue, facial trauma, or the need for cervical spine immobilization). Secondary outcomes were first-attempt success in all patients, first-attempt intubation success without hypoxemia, first-attempt duration, esophageal intubation, and hypoxemia. Among 757 patients who were randomized (mean age, 46 years; women, 230 [30%]), 757 patients (100%) completed the trial. Among the 380 patients with at least 1 difficult airway characteristic, first-attempt intubation success was higher in the bougie group (96%) than in the endotracheal tube + stylet group (82%) (absolute between-group difference, 14% [95% CI, 8% to 20%]). Among all patients, first-attempt intubation success in the bougie group (98%) was higher than the endotracheal tube + stylet group (87%) (absolute difference, 11% [95% CI, 7% to 14%]). The median duration of the first intubation attempt (38 seconds vs 36 seconds) and the incidence of hypoxemia (13% vs 14%) did not differ significantly between the bougie and endotracheal tube + stylet groups. In this emergency department, use of a bougie compared with an endotracheal tube + stylet resulted in significantly higher first-attempt intubation success among patients undergoing emergency endotracheal intubation. However, these findings should be considered provisional until the generalizability is assessed in other institutions and settings. clinicaltrials.gov Identifier: NCT02902146.

Comparison of flange slide pack technique using macintosh laryngoscope blade with conventional laryngoscopy-guided throat packing: A pilot study

Context: An analytical pilot study was conducted prospectively to ascertain the efficacy of a new method of throat packing “Flange Slide Pack Technique” (FSPT) in patients undergoing nasal, faciomaxillary, and oral surgeries. Aim: To compare the conventional technique of throat packing guided by direct laryngoscopy with FSPT where the Macintosh laryngoscope blade is used as aid for throat packing. Settings and Design: A comparative observational pilot study was conducted at a tertiary care hospital. Subjects and Methods: Subjects were randomly allocated into two groups based on the technique for throat packing by computer-generated random numbers as Group A (conventional technique) and Group B (FSPT). Primary outcomes measured were total time duration taken for packing the throat with a standardized length of ribbon gauze and changes in heart rate and change in Mean Arterial Pressure (MAP) from baseline. Secondary outcomes measured were incidence of postoperative sore throat (POST) at 6 h postoperatively and ease of insertion of the throat packs. Statistical Analysis: Parametric data were analyzed using “unpaired t-test.” Comparison of proportions and data were analyzed using Chi-square test. SPSS Version 17 (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. Results: The time taken to pack the throat was shorter in Group B; percentage increase of MAP from baseline was higher in Group A. Ease of insertion of throat pack was more in Group B. POST results were insignificant. Conclusions: FSPT can prove to be an alternative technique to the conventional method of packing the throat by minimizing duration of laryngoscopy and thereby limiting the stress response.

Haemodynamic Responses to Laryngoscopy and Intubation in Patients Undergoing Craniotomy: Comparison between Macintosh and Mccoy Laryngoscope Blades, with Monitoring of Entropy

Haemodynamic Responses to Laryngoscopy and Intubation in Patients Undergoing Craniotomy: Comparison between Macintosh and Mccoy Laryngoscope Blades, with Monitoring of Entropy

Comparison of hemodynamic changes during laryngoscopy with McCoy and Macintosh laryngoscopes

Background: The Macintosh blade is one of the most popular blades with a gently curved tongue which extends to the tip. The McCoy blade laryngoscope has a hinge on the tip to avoid the lifting force in the vallecula reducing the amount of force exerted in the vallecula causing less hemodynamic changes. Aim: An attempt had been made to compare hemodynamic changes during laryngoscopy with Macintosh and McCoy laryngoscopes in adult patients undergoing elective surgeries. Settings and Design: It was a prospective, randomized, observational study conducted between October 1, 2013, and April 10, 2015. Materials and Methods: Institutional Ethics Committee approval was taken before the commencement of the study. An informed and written consent was taken from every patient selected for the study. Sixty adults (18–60 years) of both sexes, American Society of Anesthesiologists Grade I and II, undergoing elective surgery under general anesthesia requiring endotracheal intubation were enrolled in this study. Patients were randomly divided into two groups. Group A – where McCoy laryngoscope blade was used for laryngoscopy and Group B – where Macintosh laryngoscope blade was used for laryngoscopy. After induction of anesthesia, laryngoscopy was performed, and trachea was intubated. The change in systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) was observed for 10 min post intubation. Statistical Analysis Used: It was done using SPSS. T-test and Chi-square test were applied according to the requirement. The level of significance was fixed at 95%. P < 0.05 was considered statistically significant. Results: McCoy group showed statistically significant lower values of mean HR, SBP, DBP, and MAP till 5 min after intubation when compared to Macintosh group (P < 0.05). Conclusions: HR, SBP, DBP, and MAP all did rise in both the group following laryngoscopy and intubation but changes with McCoy laryngoscope were less and statistically significant when compared to Macintosh laryngoscopes.

COMPARISON OF FOUR LARYNGOSCOPES FOR OROTRACHEAL INTUBATION BY NURSES DURING RESUSCITATION WITH AND WITHOUT CHEST COMPRESSIONS: A RANDOMIZED CROSSOVER MANIKIN TRIAL

BACKGROUND: Currently, the gold standard for airway management in cardiopulmonary resuscitation is endotra- cheal intubation. This should be performed without interruptions in chest compressions, or with a short break only to introduce the tube. METHODS: A total of 47 nurses were recruited who performed endotracheal intubation on a manikin in 2 scenar- ios: A — normal airway, without chest compressions; B — normal airway, with continuous chest compressions performed with the Lifeline ARM system. They used 4 devices: a Macintosh blade laryngoscope (MAC), and a Tru- View EVO2 (EVO2), TruView EVO2 PCD (PCD), and an ETView SL (ETView) laryngoscope. The intubation time and effectiveness, the grade of larynx visibility, and the ease of intubation in adults were compared. RESULTS: The median time to rst ventilation in scenario A was: for the MAC, 30.5 (interquartile range [IQR], 27– –36.5); for the EVO2, 35.5 (IQR, 32–39.5): for the PCD, 26.5 (IQR, 25–28.5); and for the ETView, 23 (22–24.5)’]; in scenario B: for the MAC, 47.5 (IQR, 37.5–51); for the EVO2, 42.5 (IQR, 39–47.5): for the PCD, 29.5 (IQR, 28–33); and for the ETView, 26 (IQR, 23–30.5) seconds]. The rst inbunation attempt success rate in scrnario A was: for the MAC, 44.7%; for the EVO2, 68.8%; for the PCD, 82.9%; and for the ETView, 91.5%; in scenario B: for the MAC, 38.3%; for the EVO2, 61.7%; for the PCD, 70.2%; and for the ETView 89.4%. CONCLUSIONS: The ef cacy of endotracheal intubation by nurses turned out to be insuf cient. Ongoing chest compressions signi cantly reduced the intubation effectiveness with the MAC. After a short training session, nurses could perform intubation with videolaryngoscopes. ETView appeared to be the most effective method in both scenarios.

Abstract PR527

Background & Objectives: Proper positioning of the head is essential for optimal laryngeal visualization during direct laryngoscopy. 25° back-up position has been shown to improve laryngeal view when compared with the flat supine position during direct laryngoscopy1. However, it has not been compared with the sniffing position (SP). In this prospective, randomized, crossover study we evaluated, the effect of 25° back- up position on direct laryngoscopic view compared to the sniffing position in adult patients receiving general anesthesia with endotracheal intubation. We also compared the laryngeal views in both positions with optimum external laryngeal manipulation (ELM). Materials & Methods: After Institutional Ethics Committee approval and written informed consent, 100 patients were randomized into two groups (S and B). Laryngoscopy was performed using MacIntosh laryngoscope blade size 3. Sniffing position was obtained by placing a non-compressible pillow of appropriate height so as to achieve the horizontal alignment of external auditory meatus to sternal notch2. In group S after induction of anesthesia and muscle paralysis, first laryngoscopy (L1) was done in 25° back-up position followed by laryngoscopy (L2) and intubation in sniffing position. In group B first laryngoscopy (L1) was done in sniffing position followed by second laryngoscopy (L2) and intubation in 25° back-up position. Cormack Lehane (CL) grade of laryngeal view was noted during both the laryngoscopies without and with ELM. Results: In our study we observed that 25° back-up position gives better laryngeal visualization as compared to sniffing position (p = 0.0000149). The laryngeal view improved in 33% patients, remained same in 44% and worsened in 23% patients during 25° back-up position as compared to sniffing position. However, with ELM sniffing position was better than 25° back-up position for laryngeal visualization (p = 0.00000238). Conclusion: During direct laryngoscopy, the laryngeal view, as assessed by Cormack Lehane grade, improves significantly in the 25° back-up position when compared with the sniffing position. With ELM sniffing position is better than 25° back-up position for laryngeal visualization.

Comparison of Macintosh, McCoy and Miller Laryngoscope Blades for Intubation- A Prospective Randomised Study

Maintenance of airway during anaesthesia is very important to anaesthesiologist. A prospective, randomized study was conducted in300 patients posted for various surgeries under general anaesthesia with endotracheal intubation to evaluate differences in glottic view, attempts of laryngoscopy and intubation attempts associated with the three blades- Macintosh, McCoy and Miller laryngoscope blade. They were allocated in three groups. In first group laryngoscopy was done with Macintosh blade, in second group with McCoy blade, in third group with Miller blade. In this study it was found that Cormack LehaneGrade III view was more with Macintosh and McCoy blade which was more in comparison to Miller blade. Degree of difficulty in intubation was more with Miller blade in comparison to Macintosh and McCoy blade which is statistically significant ( p value < 0.05).

Aktywność mięśni w trakcie intubacji dotchawiczej za pomocą 4 laryngoskopów (standardowego z łopatką Macintosha, Intubrite, TruView Evo2 i King Vision) – badanie porównawcze

Successful endotracheal intubation requires mental activity and no less important physical activity from the anesthesiologist, so ergonomics of used devices is important. The aim of our study has been to compare 4 laryngoscopes regarding an operator's activity of selected muscles of the upper limb, an operator's satisfaction with used devices and an operator's fatigue during intubation attempts. The study included 13 anesthesiologists of similar seniority. To measure muscle activity MyoPlus 2 with 2-channel surface ElectroMyoGraphy (sEMG) test device was used. Participant's satisfaction with studied devices was evaluated using Visual Analog Scale. An operator's fatigue during intubation efforts was evaluated by means of the modified Borg's scale. The highest activity of all the studied muscles was observed for the Intubrite laryngoscope, followed by the Mackintosh, TruView Evo2 and the lowest one - for the King Vision video laryngoscope. A significant statistical difference was observed for the King Vision and the rest of laryngoscopes (p < 0.05). No significant statistical differences were observed between the Macintosh, TruView Evo2 and Intubrite laryngoscopes (p > 0.05). The shortest time of intubation was achieved using the standard Macintosh blade laryngoscope. The highest satisfaction was noted for the King Vision video laryngoscope, and the lowest for - the TruView Evo2. The Intubrite was the most demanding in terms of workload, in the opinion of the participants', and the least demanding was the King Vision video laryngoscope. Muscle activity, namely the force used for intubation, is the smallest when the King Vision video laryngoscope is used with the highest satisfaction and lowest workload, and the highest muscle activity was proven for the Intubrite laryngoscope with the highest workload. Med Pr 2016;67(2):155-162.

TotalTrack video intubating laryngeal mask in super-obese patients - series of cases.

BackgroundSuper-obese patients are at increased risk of difficult mask ventilation and difficult intubation. Therefore, devices that allow for simultaneous ventilation/oxygenation during attempts to visualize the entrance to the larynx, increase patient safety. TotalTrack video intubating laryngeal mask is a new device that allows for ventilation during intubation efforts.Patients and methodsTwenty-four super-obese patients (body mass index >50 kg/m2) were divided into two subgroups: intubation efforts using 1) TotalTrack and 2) Macintosh blade standard laryngoscope in induction of general anesthesia. Visualization and successful intubation was evaluated for both groups with ventilation and post-mask complications additionally evaluated for TotalTrack.ResultsIn all cases in the TotalTrack group, the Cormack-Lehane score was 1, ventilation and intubation was successful in 11/12 patients. No hypoxia during intubation efforts was recorded. No serious complications of use of TotalTrack were observed. In the Macintosh blade laryngoscope group, all patients were intubated, but the Cormack-Lehane score was 2 in four cases, and 3 in three cases.ConclusionTotalTrack video intubating laryngeal mask is a device that allows for better visualization of the larynx compared to the standard Macintosh blade laryngoscope, it provides effective ventilation/oxygenation and intubation in super-obese patients.

Comparison of the force required to perform endotracheal intubation on healthy adult patients utilizing the GlideScope® videolaryngoscope and Macintosh laryngoscope: a systematic review protocol.

REVIEW QUESTION / OBJECTIVE The objective of this systematic review is to evaluate the characteristics of the force, in Newton, required to perform endotracheal intubation utilizing a GlideScope® (Verathon Medical, Bothwell, WA, USA) videolaryngoscope or a Macintosh laryngoscope on healthy adult patients. This involves the determination of the quantum of force in Newton required to visualize the epiglottis and perform the orotracheal intubation with either a GlideScope® videolaryngoscope or a Macintosh laryngoscope blade. INCLUSION CRITERIA Types of participants The target population of this systematic review will be healthy adult patients who provided informed consent for this study and were undergoing elective surgery, with or without rapid sequence intubation. Specifically, patient populations that will be included in this review are adults who are over the age of 18 with a body mass index of less than 35 and are of physical status classification 1 or 2 in accordance to the American Society of Anesthesiologist. These limiters were applied to this review's population of interest to control for the potentially increased laryngoscope handle force applied by the laryngoscopist under conditions that deviated from normal, hence confounding device-related force comparison. Laryngoscopists used must be experienced with both the GlideScope® and Macintosh laryngoscopes, as defined by having at least 25 attempts with each device. The techniques utilized for pediatric laryngoscopy as well as airway anatomy axes are not the same as those for adults; as such pediatric patients will not be included. Types of intervention(s)/phenomena of interest This review will consider studies that TRUNCATED AT 250 WORDS

Comparison of the laryngoscopy views with the size 1 Miller and Macintosh laryngoscope blades lifting the epiglottis or the base of the tongue in infants and children

Miller laryngoscope blades are preferred for laryngoscopy in infants and children <2 yr of age. Despite their long history, the laryngeal view with the Miller blade size 1 has never been compared with that with the Macintosh (MAC) blade in children. This prospective, single-blinded, randomized study was designed to compare the laryngeal views with the size 1 Miller and MAC blades in children <2 yr. With IRB approval, 50 ASA I and II children <2 yr undergoing elective surgery were enrolled. After an inhalation induction and neuromuscular block with i.v. rocuronium 0.5 mg kg(-1), two laryngeal views were obtained with a single blade (Miller or MAC) in each child: one lifting the epiglottis and another lifting the tongue base. The best laryngeal views in each blade position were photographed with a SONY(®) Cyber-shot camera and rated by a blinded anaesthesiologist using the percentage of glottic opening scale. The scores with the Miller blade lifting the epiglottis and the MAC blade lifting the tongue base were similar. The scores with the Miller blade lifting the epiglottis and the tongue base were similar. The scores for the MAC blade lifting the tongue base were greater than those lifting the epiglottis (95% confidence interval: 7.6-26.8) (P=0.0004). In infants and children <2 yr of age, optimal laryngeal views may be obtained with either the Miller size 1 blade lifting the epiglottis or with the Miller or MAC blades lifting the tongue base. NCT01717872 at Clinical Trials.gov.

Postoperative Sore Throat After Laryngoscopy With Macintosh or Glide Scope Video Laryngoscope Blade in Normal Airway Patients

Background:The Glide Scope videolaryngoscope provides a suitable view for intubation, with less force required.Objectives:The present study was conducted, to compare postoperative sore throat and hoarseness after laryngoscopy and intubation, by Macintosh blade or Glide Scope video laryngoscope in normal airway patients.Patients and Methods:Three hundred patients were randomly allocated into two groups of 150: Macintosh blade laryngoscope or Glide Scope video laryngoscope. The patients were evaluated for 48 hours for sore throat and hoarseness by an interview.Results:The incidence and severity of sore throat in the Glide Scope group, at 6, 24 and 48 hours after the operation, were significantly lower than in the Macintosh laryngoscope group. In addition, the incidence of hoarseness in the Glide Scope group, at 6 and 24 hours after the operation, were significantly lower than in the Macintosh laryngoscope group. The incidence and severity of sore throat in men, at 6 and 24 hours after the operation, were significantly lower than in the women.Conclusions:The incidence and severity of sore throat and hoarseness after tracheal intubation by Glide Scope were lower than in the Macintosh laryngoscope. The incidence and severity of sore throat were increased by intubation and longer operation times.

Inexpensive video-laryngoscopy guided intubation using a personal computer: initial experience of a novel technique

Video-laryngoscopy may provide an enhanced view of laryngeal structures compared to direct visualization. Commercial video-laryngoscopes are often expensive, limiting its adoption for routine use. We describe our initial experience using an inexpensive custom made device. Patients >15 years age, were randomly chosen, after informed consent, for video-laryngoscopy. A custom device easily assembled using an USB endoscopic camera, a conventional Macintosh laryngoscope blade size 3 or 4, and a personal computer was used. Patients with Mallampati class 1-3 were chosen. Video-laryngoscopy was recorded and reviewed. Twenty-four patients aged 16-68 years, of mean weight 58.46 ± 12.54 (40-86) kg were studied. The glottis could be visualized and intubation could be performed in all patients with 22/24 patients on first attempt. Mean duration of laryngoscopy was 22.17 ± 12.78 (7-59) s. Time taken for intubation, was mean of 28.58 ± 21.01 (9-89) s. Three patients with anticipated difficult airways could be intubated on the first attempt. Minor blood staining of the airway was seen in the video in two patients. Cormack-Lehane laryngoscopy grade visualized was 1 in 9/24, 2 in 15/24 patients. Percentage of glottic opening score was 62.29 ± 28.40 (20-100) %. Real-time video could be captured in all cases. The custom-made, inexpensive, video-laryngoscopy device is safe and reliable for clinical use. Real-time visualization and endotracheal intubation were successful in all patients, including those with anticipated difficult airway. Further, this device helps in archiving the video of intubation.

Forces generated by Macintosh and GlideScope® laryngoscopes in four airway‐training manikins

We measured forces generated by Macintosh and GlideScope(®) laryngoscope blades during airway intubation by 16 participants in four manikins: Laerdal(®) SimMan; TruCorp AirSim™ Advance; Laerdal(®) Airway Management Trainer; and Ambu(®) Airway Man. Both laryngoscopes generated the least force in the Laerdal Airway Management Trainer and the most in the Ambu Airway Man. The respective median (IQR [range]) forces generated by the Macintosh blade were 2 (1-4 [1-7]) N vs 9 (7-13 [5-16]) N, p = 0.00004, with peak forces 9 (5-11 [3-16]) N vs 18 (12-22 [3-31]) N, p = 0.0004. The respective average and peak forces generated by the GlideScope blade were 1 (1-2 [0-3]) N vs 4 (3-5 [2-6]) N, p = 0.00001, and 4 (2-7 [0-12]) N vs 7 (4-9 [3-18]) N, p = 0.054.

The Pentax airway scope versus the Macintosh laryngoscope: Comparison of hemodynamic responses and concentrations of plasma norepinephrine to tracheal intubation

BackgroundThe Pentax Airway Scope (AWS) is a video laryngoscope designed to facilitate tracheal intubation with a high-resolution image. The Pentax AWS has been reported to cause less hemodynamic stress than the Macintosh laryngoscope. The aims of this study are to investigate the differences in hemodynamic responses and norepinephrine concentrations to tracheal intubation between procedures using he Pentax AWS and the Macintosh laryngoscope.MethodsForty patients (American Society of Anesthesiologists class I-II, age range: 18-60 years) were randomly assigned to be intubated with either the Pentax AWS or the Macintosh laryngoscope while under general anesthesia. Routine monitoring, including invasive arterial blood pressure and bispectral index, were applied. Thiopental (4 mg/kg), fentanyl (1 µg/kg), midazolam (0.05 mg/kg), and rocuronium (0.6 mg/kg) were administered for anesthetic induction. Systolic, diastolic, and mean blood pressures and heart rates were recorded pre-intubation, immediately post-intubation (T0), and over the following 10 minutes at one minute intervals (T1, T2, T3, T4, T5…T10). Patient blood was sampled for norepinephrine concentrations pre-intubation (baseline) and post-intubation (T1). Evidence of sore throat was evaluated 30 min and 24 hr after extubation. Data were transformed to % basal and expressed as mean ± SD.ResultsThe systolic, diastolic, and mean blood pressure, and heart rate at T0 and T4 were significantly different between the two groups. There was no significant difference in plasma norepinephrine between the two groups. The difference in incidence of sore throat was not significant between the two groups.ConclusionsPentax-AWS for tracheal intubation has greater hemodynamic stability than the Macintosh blade laryngoscope.

Comparison of Laryngoscopic View and Hemodynamic Changes with Flexitip McCoy and Macintosh Laryngoscope Blade in Predicted Easy and Difficult Airway

Objective: To compare the laryngoscopic view and the hemodynamic changes by using flexitip McCoy laryngoscope with Macintosh laryngoscope. Method: Study design-Prospective randomized controlled study. A total of 220 patients were included in the study. Patients were allocated on the basis of their airway anatomy in to two groups, one is predicted easy group and the other one was predicted difficult airway group. Among each group, half of the patient intubation was performed with Macintosh blade and the other half was intubated with the help of McCoy blade. The airway prediction was done on the basis of Mallampati grade, thyromental distance, inter incisor gap, jaw protrusion and weight of the patient. Larygoscopic view and hemodynamic changes were recorded. Results: The change in pulse rate was significantly (p = 0.01) higher among the patients of Group B (85.02 ± 10.13) as compared to Group A (79.20 ± 13.11) after induction in predicted easy patients. Similar observation was found for pulse rate after laryngoscopy among both predicted easy and difficult patients. The diastolic blood pressure was significantly (p = 0.0001) higher in Group B (86.34 ± 9.78) than Group A (77.12 ± 11.66) after induction among predicted easy patients. However, diastolic blood pressure was significantly (p = 0.0004) higher in Group A (82.00 ± 10.98) compared with Group B (75.00 ± 9.06) after induction among predicted difficult patients. The average time taken during laryngoscopy was in-significantly (p > 0.05) higher in Group B (13.90 ± 5.95) compared with Group A (12.42 ± 3.58) among predicted easy patients. However, the time taken was significantly (p = 0.0001) higher in Group A (20.83 ± 2.47) than Group B (12.66 ± 3.0) in predicted difficult patients. A majority of the patients of both the groups were in Grade I (Group A = 61.8%, Group B = 81.8%) followed by Grade II (Group A = 38.2%, Group B = 18.2%) among predicted easy patients. Conclusion: It was concluded that the McCoy blade may be an answer to Macintosh blade in difficult airway cases, but not the substitute of Macintosh blade in every case. The McCoy blade improved laryngeal view in patients with limited neck extension.

Recycling steel from single‐use laryngoscope blades and Magill forceps

Shelton et al. 1 identified 41% of anaesthetic waste to be recyclable, including single-use stainless steel laryngoscope blades and intubating forceps. The legal position regarding re-use of single use items is clear 2: a single-use item is permitted for one patient during a single procedure. Reprocessing is prohibited; however, the regulations fail to provide any guidance on scrapping. Furthermore, although the 2011 regulations 3 describe the fate of waste laryngoscope blades in terms of incineration or ‘non-burn’ alternative treatment, recycling is not discussed. If steel was sterilised (to minimise the risk to handlers and processors) before scrapping, it could be recycled within the current UK regulations and generate an income of £1000 per tonne. Moreover, since it is no longer discarded into either clinical waste at a cost of £450 per tonne or sharps bins (£750 per tonne) the used metal is worth closer to £1500 per tonne. At University Hospital Southampton (UHS) we initiated a process for collecting and decontaminating anaesthetic room steel, similar to that in place for other surgical items at the end of their natural life The utility costs of washing and decontamination (Steris Cabinet Washer, Mentor, Ohio, USA) followed by sterilisation (BMM Weston P328, Faversham, Kent, UK) are shown in Table 5. The non-urgent nature of decontamination means that it can be undertaken at slack operating times without delaying the processing of urgent instruments. No additional staff need be employed to facilitate this process. The size-4 Macintosh laryngoscope blade weighs 106 g and a pair of adult Magill's intubating forceps 72 g, with scrap values of 10.6 and 7.2 pence, respectively. The maximum number of laryngoscope blades per tray is limited by space and weight to approximately 60. Both washer and steriliser cycles can process up to five fully laden trays containing 300 laryngoscope blades (31.8 kg of steel). Assuming each cycle runs to maximum efficiency, the cost is 1.34 pence per blade. Extrapolating these results to the envisaged use at UHS of 20 000 laryngoscope blades per year, the scrap value is £2120, the saving of not disposing of the waste an additional £1060, less the processing cost of £268. Our Trust stands to save £2912 per annum. Whilst Shelton et al. claim that recycling anaesthetic waste is beneficial in terms of both financial savings and reducing carbon emissions, we believe they have underestimated the environmental impact. The energy expenditure to produce 1 kg of steel from iron ore is over 10 MJ greater than when produced from recycled scrap steel (21.9 MJ vs 11.7MJ) and the carbon footprint associated with producing 1 kg of steel from iron ore is 1.97 kg vs 0.7 kg of CO2 if that steel comes from scrap 4. Almost all single-use laryngoscope blades are manufactured in Pakistan and then transported thousands of miles, to be used once only and for less than a minute. This is reflected in the carbon intensity of disposable items and is currently 600 g CO2 per £GB spent 5, or approximately 3.0 kg per laryngoscope blade. We agree with Shelton et al. and conclude that the process of recycling anaesthetic room steel reduces environmental harm and benefits hospitals economically. Furthermore, we support the authors’ call for clearer guidance on recycling anaesthetic room steel. If we cannot reduce the need for laryngoscopy and re-usable laryngoscope blades have all but been removed, then recycling the steel is perhaps the only sustainable option and steel saves both carbon and money.

A randomised trial comparing the CEL‐100 videolaryngoscopeTM with the Macintosh laryngoscope blade for insertion of double‐lumen tubes

We performed a randomised trial comparing the CEL-100 videolaryngoscope(TM) with the Macintosh laryngoscope blade in 170 patients undergoing double-lumen tube placement for thoracic surgery. Compared with the Macintosh laryngoscope blade, use of the CEL-100 resulted in significantly more patients with a Cormack and Lehane Grade-1 laryngeal view (90.4% vs 61.0%, p < 0.001), a higher rate of successful intubation on the first attempt (92.8% vs 79.3%, p = 0.012), a lower median (IQR [range]) intubation difficulty score (0 (0-0 [0-60]) vs 15 (0-30 [0-80]), p < 0.001), a higher incidence of correct positioning of the tube (90.3% vs 79.2%, p = 0.041) and significantly fewer patients requiring external laryngeal pressure (19.3% vs 32.9%, p = 0.046). Median (IQR [range]) time to successful intubation was 45 (38-55 [22-132]) s with the CEL-100 compared with 51 (40-61 [30-160] s using the Macintosh laryngoscope blade. We conclude that the CEL-100 videolaryngoscope is superior to the Macintosh laryngoscope blade for double-lumen tube insertion.

Videolaryngoscopy offers advantages over classic laryngoscopy in a patient with seriously limited lip opening

To the Editor: Inability to intubate the trachea is a leading cause of anesthesia-related injury [1]. Videolaryngoscopy offers advantages over direct laryngoscopy and is less traumatic [2, 3], as the miniature videocamera on the tip of the blade enables the intubator to provide an indirect view of the upper airway. We report a patient with limited lip opening in whom videolaryngoscopy proved to be helpful to provide a patent airway. A 73-year-old woman (160 cm; 75 kg; American Society of Anesthesiologists [ASA] physical status II), scheduled for lip reconstruction following lower lip cancer, underwent extensive lower lip resection with upper lip rotation (AbbeEstlander flap) to fill the lower lip defect [4]. Both lips were sewn together for 6 weeks, leaving an oral opening of 2.6 cm (intercommissural width). At the time of lip reconstruction (dividing the pedicle and releasing the lips), the patient showed asymmetric and limited mouth opening (interincisor distance 1.2 cm, oral width 2.6 cm; thyromental distance 6.8 cm; Mallampati grade IV), normal neck movement, and an adequate oral space. Precautions were taken to deal with a difficult airway: i.e., the provision of a difficult airway trolley, and personnel skilled in performing a surgical airway. After preoxygenation, anesthesia was induced with i.v. propofol 200 mg. Face mask ventilation was successful with capnographic tracing, and 100 mg succinylcholine was administered. The narrow mouth orifice prohibited any direct vision of the oral cavity during direct classic laryngoscopy (Cormack–Lehane grade IV), resulting in excessive tension on both lips. Channeled indirect videolaryngoscopes (Pentax-AWS , Tokyo, Japan; Airtraq , Prodol-Meditec, Vizcaya, Spain) were considered, but they were found to be too bulky to fit into the patient’s mouth, and failed to work, indicating that the wider blades of channeled videolaryngoscopes are a weak point. The insertion of a V-MAC videolaryngoscope (Karl Storz , Tutlingen, Germany), which consists of a less wide Macintosh-blade size three, into the mouth (Fig. 1) showed a Cormack–Lehane grade I on the monitor, and oral endotracheal intubation was successful at the first attempt, without the need to use a stylet. Normally a Macintosh-blade laryngoscope is introduced into the right side of the mouth, deflecting the tongue to the left, and the length of the blade is passed over the contour of the tongue. Subsequently the tongue is lifted upwards and forwards, so that enough room is created next to the blade to both visualize the glottic entrance and to insert the endotracheal tube in situ. In this patient no such maneuvers were an option. This case highlights the advantage of indirect videolaryngoscopy (Macintosh intubation blades incorporating optics in the tip for video-imaging) in patients with very limited mouth openings. The intubator does not need to see the vocal cords directly, as videolaryngoscopy offers both better laryngoscopic views and more successful intubations than classic laryngoscopy [2, 3, 5]. Management of difficult laryngoscopy in the patient with seriously reduced opening of the lips offers a unique and ongoing challenge for the anesthetist. With the present A. van Zundert (&) B. Pieters Department of Anesthesiology, Intensive Care and Pain Therapy, Catharina Hospital-Brabant Medical School, Michelangelolaan 2, NL-5623EJ, Eindhoven, The Netherlands e-mail: zundert@iae.nl

Successful Tracheal Intubation Using the Airtraq in Thoraco-omphalopagus Twins

To the Editor Tracheal intubation in conjoined twins, especially thoraco-omphalopagus twins, represents a unique challenge because of the varying extent of anatomical development and awkward positioning.1 We successfully intubated the tracheas of thoraco-omphalopagus twins using the Airtraq® (Prodol Meditec S.A., Vizcaya, Spain) (Fig. 1).Figure 1: Thoraco-omphalopagus twins after intubation (identified as A, on the right, and B, on the left).Female thoraco-omphalopagus conjoined twins, 40 days old, weighing 6.5 kg, were scheduled for surgical separation. The use of Airtraq optical laryngoscope in children was approved by the Human Ethics Committee of West China Hospital, and the parents provided informed consent. Preoperative studies showed a large cross-abdominal liver and separate hearts in a single pericardial sac combined with a left-sided superior vena cava of twin A draining into the coronary sinus of twin B. Both twins presented with micrognathism, high-vaulted arch, and short neck, and therefore difficult airway management was anticipated. After they were placed on the operating table with their necks slightly hyperextended, routine monitoring was established. Anesthesia was induced with sevoflurane, midozalam, and low-dose fentanyl with the intention to intubate the tracheas under deep sedation while maintaining spontaneous respiration. After the disappearance of eyelash reflex, tracheal intubation in twin B using a Macintosh laryngoscope blade size 1 was attempted by an experienced pediatric anesthesiologist with the twins in the lateral position to avoid significant hemodynamic compromise. Only the tip of the epiglottis was viewed and Cormack and Lehane grade III difficulty of intubation confirmed. Withdrawing the laryngoscope resulted in laryngospasm similar to that described by Shank1 and was resolved by administration of propofol. According to our preoperative protocol, we planned that the trachea of the second twin should be intubated. Therefore, while twin B underwent mask ventilation, the trachea of twin A was intubated without difficulty using an Airtraq optical laryngoscope (AOL; Prodol, Vizcaya, Spain), directly after which twin B was given succinylcholine 3 mg IV and tracheal intubation performed for twin B in a similar fashion. Although thoraco-omphalopagus twins usually present with an inflexible position, tracheal intubation can be achieved with the twins in the lateral and partly rotated position in most cases, rather than holding one baby above the other.2,3 We prefer deep sedation, maintaining spontaneous breathing in the management of anticipated difficult intubation. Transient laryngospasm occurring in our case was probably due to inadequate depth of anesthesia. Had our attempt using video-laryngscopy not been successful, we were prepared to use fiberoptic and rigid Seldinger-assisted video-telescopic intubation, as successfully applied in other similar cases.4–6 Jing Lin, MD Bin Liu, MD Ling Tan, MD Yun-Xia Zuo, MD, PhD Department of Anesthesiology West China Hospital Sichuan University Chengdu, Sichuan People's Republic of China [email protected]