Laryngeal View Research Articles

The successful use of sugammadex and uneventful recovery from general anaesthesia in a patient with myotonic dystrophy.

Sir, Myotonic dystrophy is an autosomal dominant multisystem disorder characterised by progressive weakness and wasting of muscles, cardiomyopathy and cardiac conduction defects, restrictive lung disease, sleep apnoea syndrome, slow gastric emptying, endocrine disorders and cataracts. This condition is often associated with prolonged muscle contractions with defective relaxation (myotonia). There are two major types of myotonic dystrophy: Type 1 and type 2. These are caused by mutations in different genes. Anaesthetic management of this condition can be challenging due to the potential for these patients to develop perioperative cardiorespiratory complications and because they may demonstrate abnormal responses to sedative and neuromuscular blocking agents. We present a report of the successful management of a 60-year-old gentleman with myotonic dystrophy type 1, weighing 70 kg, who presented for elective laparoscopic cholecystectomy. His symptoms had included progressive weakness of the upper limbs with dysarthria, soft voice and mild static swallowing impairment. He had dilated cardiomyopathy and had a pacemaker/defibrillator in situ. The patient also had moderate obstructive sleep apnoea and was saturating at 99% in room air. This patient had never undergone general anaesthesia, and all his previous investigations had been performed previously under local anaesthesia with sedation. Pre-operative examination findings included the characteristic facial features of myotonic dystrophy and a modified Mallampati class III. On the day of surgery, no oral pre-medication was given other than his usual medications. Intra-operative monitoring included five-lead electrocardiography, pulse oximetry, capnography, invasive blood pressure monitoring with a right radial artery catheter and bispectral index (BIS). Magnet and external defibrillator pads were placed over his chest. Following adequate pre-oxygenation, induction and maintenance of anaesthesia were carried out with 0.5 mg of midazolam followed by propofol and remifentanil target controlled infusion titrated to BIS between 40 and 60 and haemodynamic status. After the initial administration of 50 mg rocuronium for intubation anticipating approximately 2 h procedure, we had planned to give subsequent doses guided by a peripheral nerve stimulator. A grade II b laryngeal view was obtained with direct laryngoscopy and a size 8.5 endotracheal tube was inserted. The maintenance phase of anaesthesia was uneventful, and no other analgesia was given intra-operatively. Upper and lower body forced air warmers were used throughout. The surgery was uncomplicated and lasted 45 min. At the end of surgery as no twitches were observed with train-of-four (TOF) stimulus after the initial intubating dose of rocuronium, the decision was made to reverse neuromuscular blockade with an initial sugammadex dose of 200 mg and further administer additional doses if necessary. Interestingly with the initial dose, all the four twitches to TOF stimuli appeared with no fade, merely within 30 s. Furthermore, there was no obvious fade with double burst stimulation. The patient was extubated when fully awake after a smooth emergence. His oxygen saturation was 99% with 5 L/min of supplemental oxygen. The patient was admitted to the Intensive Care Unit for observation and had an uncomplicated recovery. Patients with myotonic dystrophy often have respiratory muscle weakness resulting in an ineffective cough. This can co-exist with a decreased ventilatory response to hypoxia and hypercapnia. Pharyngeal muscle weakness and prolonged gastric emptying may increase the risk of aspiration. As a consequence, there is a possibility of increased postoperative pulmonary complications in this patient group.[1] Suxamethonium can result in exaggerated contracture in patients with myotonic dystrophy.[1] It may be difficult to predict the reaction to neostigmine in these patients as it can result in aggravation of paralysis or myotonia.[2,3] Peripheral nerve stimulation itself can also result in a myotonic response that may be misinterpreted, as sustained tetanus.[1] Residual neuromuscular blockade may further increase the risk of postoperative pulmonary complications in these patients. Sugammadex, a modified gamma-cyclodextrin, selectively binds with rocuronium or vecuronium to reverse the neuromuscular blocking effect. It is devoid of the risks of neostigmine and with better efficacy at reversal, has been suggested as a superior alternative.[4,5,6] We had decided to use rocuronium and sugammadex combination, to avoid the possible need for neostigmine to reverse any other relaxant as well as because of lack of quantitative neuromuscular monitoring with which we could ensure complete reversal. In contrast to the previous reports, where sugammadex was either given to avoid the possibility of residual paralysis[4] or less than normal dose of rocuronium was given for intubation,[6] we observed that using sugammadex, we could easily reverse a complete paralysis following the usual intubating dose of rocuronium (approximately 0.6 mg/kg). We therefore suggest that sugammadex, if available, should be considered for reversal of neuromuscular blockade with steroidal non-depolarising muscle relaxants in patients with muscular disorders such as myotonic dystrophy, particularly in facilities where advanced neuromuscular monitoring is unavailable.

Comparison of Macintosh laryngoscope and C-MAC video laryngoscope for intubation in lateral position.

Background and Aims:Endotracheal intubation is conventionally performed when the patient is in supine position. It may be required to secure airway in laterally positioned patient. Tracheal intubation in lateral position seems to be difficult because the laryngeal view is compromised. Hence, C-MAC video laryngoscope (Karl Storz, Germany), a newer device using a modified macintosh blade may be useful for intubation in lateral position.Material and Methods:A total of 100 American Society of Anesthesiologists Grade I and II patients, randomly allotted to C-MAC or direct laryngoscopy group. Patients with difficult airway were excluded. After induction of anesthesia, patient was put in right-lateral position and intubation was carried out by consultant who is well-versed in using C-MAC laryngoscope. Time for intubation, number of attempts, Modified Cormack – Lehane grade, mucosal injury, and external laryngeal manipulation applied were noted.Statistical Analysis:Demographics and baseline airway assessments were analyzed using summary statistics. Unpaired t-test was used to assess intubation time. Number of attempts, esophageal intubation, dental injury, mucosal injury, use of stylet, and application of external laryngeal manipulation were analyzed using Chi-square test.Results:Overall intubation success rate was 100%. The time taken in C-MAC group was 24.8 ± 8.5 s and in direct group was 33.8 ± 9.12 s. The number of intubation attempts was not significant. Cormack – Lehane grade was better with C-MAC laryngoscope. Mucosal injury and use of external laryngeal manipulation was more in direct group.Conclusion:C-MAC is better than Macintosh laryngoscope for intubation in lateral position.

Anticipated Difficult Tracheal Intubation: Comparison between conventional laryngoscope (Macintosh) and video laryngoscope TrueView EVO2

Context: In patients with anticipated difficult airway, it is difficult to align the oropharyngolaryngeal axis to facilitate intubation by conventional laryngoscopy, which leads to failed intubation. The TruView EVO 2 laryngoscope is a device with a unique blade that provides an optical view around the corner. The blade is a modified laryngoscope blade incorporating an unmagnified optic side port with anterior fraction of 42΀ in the line of sight allowing indirect tracheal intubation. Aim: The aim of the study was to compare TrueView blade with Macintosh blade with respect to the (view of the glottis by (Cormack-Lehane grading); Time for tracheal Intubation, Attempts required for intubation, maneuvers to optimize the laryngeal view and success rate of intubation); Settings and Design: It was a prospective, randomized controlled single blind clinical study. Materials and Methods: Seventy ASA grade I and II, Mallampatti Grading (MPG), III and IV patients posted for elective surgery with restricted neck mobility such as post-burn contracture neck, cervical spine surgeries divided into Group 1-35 patients (Trueview) and Group 2-35 patients (Macintosh). All intubation was done by an expert anesthesiologist. Statistical Analysis: Tests used were Mann-Whitney U test, two independent sample t-tests, Chi-square test, and Fischer's exact t-test. Results: Cormack-Lehane Grade I was seen in 62.85% and O in Group 1 and Group 2, respectively. Grade II was seen in 37.14% and 28.57% in Group 1 and Group 2, respectively, and Grade III in 0 and 71.42% in Groups 1 and 2, respectively, which was statistically significant. Thus EVO 2 improved the view of glottis by 2 Grades. Both the techniques were comparable as far as time is concerned. A 94.2% patients in Group 1 intubated in 1 st attempt, 5% needed 2 nd attempt, whereas in Group 2 72.7% patients were intubated in 1 st attempt and 27.2% in 2 nd attempt. Maneuver BURP required more with conventional laryngoscopy. Success rate in Group 1 was 100% and in Group 2 it was 94.2%. Conclusion: The use of TrueView in patients with anticipated difficult airway considerably improved the view of glottis. With adequate experience, the number of attempts may be reduced and maneuver required for securing airway successfully could be optimized.

Higher Operating Tables Provide Better Laryngeal Views for Tracheal Intubation

Lee, H.-C.*; Yun, M.-J.†; Hwang, J.-W.‡; Na, H.-S.‡; Kim, D.-H.†; Park, J.-Y.§ Author Information

Head elevation improves laryngeal exposure with direct laryngoscopy

Study objectiveThe aim of this study was to examine the effect of changing head position on the laryngeal view in the same subject. DesignProspective, randomized, crossover comparison of laryngeal views. SettingOperating suite at a university-affiliated, community hospital. PatientsOne hundred sixty-seven consenting adult patients scheduled to undergo elective surgery with general anesthesia. InterventionsAfter anesthesia induction and muscle relaxation and the head in extended position, the laryngeal view was graded in 3 different head height positions. A special inflatable pillow was placed under the subject's head before induction and was deflated to produce no head elevation or inflated to produce either 6.0cm (sniffing position), or 10.0cm elevation (elevated sniffing position) in random order. Main resultsThe incidence of difficult laryngoscopy (grade ≥3) was 8.38% with no head elevation, 2.39% in the sniffing position, and 1.19% in the elevated sniffing position. Head elevation was not associated with a worse grade in any single patient. ConclusionsSniffing position improves glottic exposure when the laryngoscopic grade is greater than 1 in the head-flat position. The elevated sniffing position improves the view to a better grade in some patients. Because head elevation was not associated with a worse grade in any subject, the elevated sniffing position should be considered as the initial head position before direct laryngoscopy when a difficult exposure is anticipated.

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.

The evaluation of brain natriuretic peptide changes and difficult airway predictors during perioperative period of pregnancy.

Airway changes, difficult ventilation, and intubation are the leading causes of morbidity and mortality in pregnancy, but no prospective study has evaluated the relationship between airway changes and brain natriuretic peptide (BNP) before and after cesarean section operations. The purpose of this study was to evaluate the relationship between BNP and airway changes in women undergoing delivery and during the postoperative period. Included in this prospective study were a total of 35 pregnant females with ASA I physical status who were scheduled for cesarean section under general anesthesia. BNP levels, Mallampati classification, mouth opening, thyromental distance, sternomental distance, and the degree of neck extension were recorded before cesarean section and 24 h after the operation. Laryngeal views were also documented after intubation. Significant differences in BNP levels, Mallampati classification, mouth opening, thyromental distance, sternomental distance, and the degree of neck extension measurements arose between initial measurements and those measurements made 24 h postoperatively. Pre-delivery Mallampati I, II, III, IV scores of 6, 18, 7, 4 had by 24 h after cesarean section changed to 13, 13, 6, 3, respectively (p < 0.05). Initial BNP levels were 7.59 ± 6.30; postoperative levels were 52.39 ± 48.17. In this study we found a correlation between perioperative BNP levels and difficult intubation parameters. Within 24 h postpartum, Mallampati scores changed in 13 patients (30.95 %). Besides the correlation between BNP levels and difficult intubation parameters, we also found significant differences in initial and postoperative BNP values.

Macintosh or Miller Laryngoscope Blades for Infants

The straight Miller laryngoscope blade is traditionally recommended for intubation in infants, due to the large size and flexibility of the infant epiglottis. However, the Miller and Macintosh blades have not been systematically compared in young children. In a prospective, single-blind, randomized study, researchers compared laryngeal views obtained with size 1 …

Capnography in anesthetic management for laryngeal microsurgery

Suspension laryngoscopy and laryngeal microsurgery present significant challenge to the anesthesiologist due to the fact that anesthetic equipment hinders surgical approach and visibility of laryngeal structures. High frequency jet ventilation is a of method of choice for most of the endolaryngeal procedures as it allows unimpaired view of larynx and can be delivered via small catheters. However, despite improved oxygenation, elimination of carbon dioxide may be significantly affected and patients' СО2 status has to be monitored strictly. Being widely considered as the most reliable method for assessment of carbon dioxide elimination, capnograhy has obvious limitations in the case of high frequency jet ventilation. At the same time, double lumen jet ventilation catheters have a potential of monitoring СО2 status using side stream sensors. The present study offers analysis of 50 endoscopic laryngeal procedures performed under general anesthesia with subglottic high frequency jet ventilation via double lumen jet catheter. The assessment of СО2 levels was performed intermittently along with decrease in ventilation frequency to physiological values (10–12 per minute). For relatively long procedures (e.g. surgical repair of bilateral vocal cord paralysis) arterial blood sampling was done in order to measure СО2 levels directly in arterial blood. Obtained data showed no significant retention of СО2 under high frequency jet ventilation. Intermittent short-term (less then one minute) decrease in ventilation rate allows to utilize capnography as a reliable monitoring method to assess respiratory efficiency of subglottic high frequency jet ventilation during microsurgery of the larynx.

Comparative study between LMA-Proseal™ and Air-Q® Blocker for ventilation in adult eye trauma patients

BackgroundThe disposable Air-Q® Blocker Masked Laryngeal Airway (MLA) is a new supraglottic device used for intubation, rescue ventilation, and for esophageal suctioning. Laryngeal Mask Airway-Proseal™ is a well known supraglottic device in clinical practice. The aim of the study was to compare Air-Q® Blocker against LMA-Proseal™ as supraglottic devices for ventilation.MethodsSixty adult healthy patients scheduled for eye trauma surgeries under general anesthesia were randomly allocated into 2 groups; Group A (n = 30), where Air-Q® Blocker is used, Group P (n = 30), where LMA-Proseal™ is used. The success rate and time of their insertion were measured. Laryngeal view grading was assessed by fiberoptic bronchoscope. Ease of gastric tube placement and any post-operative complications (airway edema, sore throat or hoarseness) were also measured. Stress response of device insertion was measured using the vital sign measurements.ResultsSuccess of insertion at 1st attempt was (90%) in Group A and (83.3%) in Group P. Insertion time was 18.37 ± 3.77 s in Group (A), while 23.43 ± 3.54 s in Group P, (p < 0.001). Airway seal pressure was comparable in both groups. Full view of vocal cords amounted to (76.7%) in Group A, and (56.7%) in Group P respectively. 1st Attempt Gastric Tube Insertion was (93.3%) in Group A, and (83.3%) in Group P. comparison of previous data in both groups showed no statistical significant differences between them. The incidence of postoperative complications and post insertion hemodynamic stress response was statistically nonsignificant when compared between the 2 groups.ConclusionThe Air-Q® Blocker demonstrated to be remarkably good as a ventilatory device, with adequate airway seal pressure, and improved facilitation of gastric tube insertion compared to LMA-Proseal™. Minimal pressor response was achieved after insertion with no statistical significance.

The Process of Prehospital Airway Management

Endotracheal intubation success rates in the prehospital setting are variable. Our objective was to describe the challenges encountered and corrective actions taken during the process of endotracheal intubation by paramedics. Analysis of prehospital airway management using a prospective registry that was linked to an emergency medical services administrative database. Emergency medical services system serving King County, Washington, 2006-2011. Paramedics in this system have the capability to administer neuromuscular blocking agents to facilitate intubation (i.e., rapid sequence intubation). A total of 7,523 patients more than 12 years old in whom paramedics attempted prehospital endotracheal intubation. None. An intubation attempt was defined as the introduction of the laryngoscope into the patient's mouth, and the attempt concluded when the laryngoscope was removed from the mouth. Endotracheal intubation was successful on the first attempt in 77% and ultimately successful in 99% of patients (7,433 of 7,523). Paramedics used a rapid sequence intubation strategy on 54% of first attempts. Among the subset with a failed first attempt (n = 1,715), bodily fluids obstructing the laryngeal view (50%), obesity (28%), patient positioning (17%), and facial or spinal trauma (6%) were identified as challenges to intubation. A variety of adjustments were made to achieve intubation success, including upper airway suctioning (used in 43% of attempts resulting in success), patient repositioning (38%), rescue bougie use (19%), operator change (16%), and rescue rapid sequence intubation (6%). Surgical cricothyrotomy (0.4%, n = 27) and bag-valve-mask ventilation (0.8%, n = 60) were rarely performed by paramedics as final rescue airway strategies. Airway management in the prehospital setting has substantial challenges. Success can require a collection of adjustments that involve equipment, personnel, and medication often in a simultaneous fashion.

Pentax Airway Scope® vs Macintosh laryngoscope for tracheal intubation in adult patients: a systematic review and meta‐analysis

The Pentax Airway Scope(®) is a single-use optical videolaryngoscope designed to assist with difficult tracheal intubation. We systematically reviewed the efficacy of the Pentax Airway Scope with that of a conventional laryngoscope for tracheal intubation in adults with 'normal' and 'difficult' airways. We included 17 randomised controlled trials with a total of 1801 participants. We used the DerSimonian and Laird random-effects model to calculate pooled relative risk or weighted mean differences. The relative risk (95% CI) of a Cormack-Lehane grade-1 laryngeal view was 2.40 (1.76-2.49) with the Pentax Airway Scope compared with the Macintosh laryngoscope, p < 0.00001. We found no other differences between the two laryngoscopes. Despite a superior laryngeal view, the Pentax Airway Scope provides little clinical benefit over the conventional laryngoscope.

The LMA-Supreme versus the I-gel in simulated difficult airway in children

Supraglottic airway devices such as the LMA-Supreme (LMA-S) and I-gel, which have an additional lumen for the insertion of a gastric tube, can be useful in the management of the difficult airway. To test the performance of these two devices in the difficult paediatric airway. Randomised double-blind study. Anaesthesia department, university hospital. Sixty American Society of Anesthesiologists (ASA) I-II children undergoing elective surgery. After obtaining ethical approval and written informed consent from the parents, we compared the size 2 LMA-S with the I-gel in a simulated airway scenario made more difficult by using a cervical collar to limit mouth opening and neck movement. The primary aim was to compare the oropharyngeal leak pressure of the LMA-S and the I-gel. The secondary aims were to compare success rate, insertion time, time to pass a gastric tube and fibreoptic view of the larynx. Oropharyngeal leak pressure (mean ± SD) for the LMA-S was significantly higher than with the I-gel (20.9 ± 3.2 versus 18.9 ± 3.2 cmH2O, P = 0.019). First attempt success rate for the LMA-S was 100 and 90% for the I-gel (P > 0.05). Insertion time of the LMA-S was shorter than I-gel (11.2 ± 1.8 versus 13.5 ± 2.4 s, P = 0.001). Gastric tube placement was possible in all patients. The mean insertion time of the gastric tube was shorter with the LMA-S than with the I-gel (10.3 ± 3.6 versus 12.7 ± 3.2 s, P = 0.009). Fibreoptic laryngeal views were similar in both groups. In the simulated difficult airway in children, both airway devices provided effective ventilation. Paediatric size 2 LMA-S sustained a higher airway pressure before leaking and was quicker to insert than the I-gel equivalent. These differences may not be clinically significant.

Higher operating tables provide better laryngeal views for tracheal intubation

The present study was conducted to investigate the influence of different operating table heights on the quality of laryngeal view and the discomfort of the anaesthetist during enodotracheal intubation. Eight anaesthetists participated, to each of whom 20 patients were allocated. Before induction of anaesthesia, the height of the operating table was adjusted to place the patient's forehead at one of four landmarks on the anaesthetist's body (the order being determined by block randomization with eight blocks): umbilicus (Group U), lowest rib margin (Group R), xiphoid process (Group X), and nipple (Group N). Next, the anaesthetist began the laryngoscopy and evaluated the grade of laryngeal view. For this 'initial posture', the anaesthetist was not allowed to adjust his or her posture (flexion or extension of the neck, lower back, knee, and ankle). This laryngeal view was then re-graded after these constraints were relaxed. At each posture, the anaesthetist's joint movements and discomfort during mask ventilation or intubation were evaluated. The laryngeal view before postural changes was better in Group N than in Group U (P=0.003). The objective and subjective measurements of neck or lower back flexion during intubation were higher in Group U than in Groups X and N (P<0.01 for each). The improvement of laryngeal view resulting from postural changes correlated with the anaesthetist's discomfort score before the postural change (P<0.01). Higher operating tables (at the xiphoid process and nipple level of the anaesthetist) can provide better laryngeal views with less discomfort during tracheal intubation. TRIAL REGISTRY NUMBER: NCT01649973 (clinicaltrials.gov).

Comparing performance of different laryngoscope blades

Editor, In a randomised clinical study, Buléon et al.1 showed that the Heine XP plastic single-use blade resulted in an increase in the intubation failure rate and a worse laryngeal view compared with the Heine metallic reusable blade and the Callisto metallic single-use blade. The power of this study is its use of a large sample, and the authors have controlled some factors that can significantly affect the laryngeal visualisation and tracheal intubation, such as patient's characteristics and upper airway anatomy, blade sizes and use of anaesthetic and neuromuscular blocking drugs.2,3 Additionally, the authors openly discuss the limitations of their work. However, we note other issues of this study making interpretation of their results questionable. First, in the method section, the authors stated that the position of the patients’ head and neck during direct laryngoscopy was recorded after intubation. In the results section, these data are not provided and compared. Proper positioning of the head and neck (for example, sniffing position) is essential for optimal laryngeal visualisation during direct laryngoscopy and inadequate positioning may result in prolonged or failed tracheal intubation attempts because of the inability to visualise the larynx.4 Moreover, we do not feel that the authors clearly described whether they had achieved an optimal attempt at laryngoscopy when evaluating the laryngoscopic views obtained with the three blades. Second, there was no mention of how many experienced anaesthesiology nurses or physicians participated in this study. Metallic reusable blades are devices that are frequently used for tracheal intubation. There are many single-use blades on the market and these differ greatly in their main characteristics, such as configuration, quality and robustness.5–8 Unfortunately, the authors did not explain whether there were significant differences in shape, length, angulation, rigidity, light intensity and brightness field among the three blades that were tested in their study. More importantly, it remained unclear whether all participants had used the plastic and metallic single-use blades in routine tracheal intubation before this study. Differently shaped blades may require different laryngoscopic techniques and may even result in difficulty in laryngoscopy and tracheal intubation performed by a novice user.5,8 Thus, we cannot exclude the possibility that different experiences and proficiency levels of participants with the three blades tested in this study attribute to the findings. Here, we would like to share the viewpoint of Behringer et al.9 that in a comparative intubation study, for the results to be valid, participants must be equally proficient with each tested device in order to avoid bias. Third, sample size was selected to detect a difference of 3% in the rate of intubation failure between the metallic reusable and the single-use blade groups and the plastic single-use blade group. However, of 1863 eligible patients, 190 (10.2%) were excluded from the final analysis because of missing data. The authors did not explain whether these excluded patients were equally distributed among the three study groups. A significantly higher rate of missing data in any group may have biased the final analysis of the results. Fourth, the intubation difficulty scale (IDS) is the sum of the seven parameters associated with the intubation effort. An IDS score 1 to 5 indicates slight intubation difficulty and an IDS score more than 5 indicates moderate to major intubation difficulty.10 In this study, a notably higher IDS score in the plastic single-use blade group was mainly due to a higher number of patients with IDS scores 1 to 5 in the plastic single-use blade group compared with the metallic reusable and single-use blade groups. In clinical practice, intubation difficulty with IDS scores 1 to 5 should not be a problem for experienced anaesthesiologists. Adnet et al.10 demonstrated that when IDS was 5 or less, intubation time did not vary significantly. When IDS was more than 5, however, intubation time increased rapidly in relation to the score.10 As a result, an IDS score of more than 5 is often defined as difficult intubation and used as the primary outcome of a comparative study.8,11 In the study by Buléon et al.,1 the incidence of an IDS score of more than 5 did not significantly differ between the study groups. Finally, apart from the blade types, interaction of many other factors can also affect the ease of laryngoscopy and success rate of tracheal intubation.3,4 Thus, we feel that the study by Buléon et al.1 does not provide high-level evidence to support the conclusion that the plastic single-use blade is less efficient than the metallic reusable and single-use blades. Acknowledgements relating to this article Assistance with the letter: none. Financial support and sponsorship: none. Conflicts of interest: none. Comment from the editor: Dr Buléon and colleagues did not wish to respond to this letter.

Comparative study between Air-Q and Intubating Laryngeal Mask Airway when used as conduit for fiber-optic

This study compared Air-Q and Intubating LMA when used as a conduit for endotracheal intubation.MethodsOne hundred patients scheduled for surgical operations under general anesthesia were randomly allocated into two equal groups (n = 50). Group I: Air-Q and group II: Intubating Laryngeal Mask Airway (ILMA) in both groups intubation was done by Fiberoptic bronchoscope (FOB) through study device. After induction of anesthesia, patients were ventilated with Air-Q or ILMA. Then, endotracheal tube (ETT) was inserted through study device. Recorded measurements were as follows: number of attempts and duration of insertion of device, peak airway pressure and fiberoptic grading of laryngeal view. Also, we recorded number of attempts and duration of insertion of ETT and the incidence of blood stain on device and sore throat grading.ResultsDuration of insertion of Air-Q was 13.300 ± 3.471 s, whilst that of ILMA was 19.640 ± 4.737 s (p < 0.001). In group I, peak airway pressure was 26.400 ± 2.176 cmH2O, whilst, in group II, it was 25.260 ± 1.468 cmH2O (p < 0.01). Full view of vocal cords amounted to 78% and 26% of Groups I and II patients, respectively (p < 0.001). Time of insertion of ETT was 33.5 ± 6.795 s in group I, whilst in group II, it was 39.5 ± 6.566 s (p < 0.001). Blood stain was found on supraglottic device in 46% and 22% of cases in Groups I and II, respectively (p < 0.01).ConclusionAir-Q proved to be an excellent conduit for endotracheal intubation compared to the ILMA.

Clinical experience with the C-Mac videolaryngoscope in morbidly obese patients

The use of videolaryngoscopes is recommended as a part of routine practice in anaesthesia for morbidly obese patients. The aim of this study was to evaluate C-Mac in a group of morbidly obese patients to see if it improves intubation conditions. 86 morbidly obese (BMI > 40 kg m⁻²) patients scheduled for bariatric surgery were included in the study. In every studied case, C-Mac was used with a Mackintosh shaped blade. For the first attempt, the anaesthetists performing the intubation were asked to use a videolaryngoscope as a standard laryngoscope (they were blinded to the monitor display) and evaluate the glottic view in direct laryngoscopy. Then they were asked to look at the monitor of the videolaryngoscope and intubate the patient. The laryngoscopy conditions were evaluated using the Cormack-Lahane (CL) scale. The time from picking up the laryngoscope to inserting the endotracheal tube was recorded. The evaluation of CL grade in direct laryngoscopy was: 44 patients - grade 1; 23 patients - grade 2; 13 patients - grade 3; six patients - grade 4. In all cases of CL grade > 1 in direct laryngoscopy, the use of C-Mac improved CL grade to 1. Mean time of intubation was 17.2 ± 2.5 sec. The C-Mac improves laryngeal view in morbidly obese patients, and allows for fast endotracheal intubation.

From the Journal archives: Early clinical experience with a new video laryngoscope

Cooper RM, Pacey JA, Bishop MJ, McCluskey SA. Early clinical experience with a new videolaryngoscope (GlideScope®) in 728 patients. Can J Anesth 2005; 52: 191-8. This investigation was an observational study designed to evaluate the newly developed GlideScope video laryngoscope (GVL) and to assess its ability both to provide a laryngeal view and to facilitate intubation. The study, which was conducted from November 2001 to March 2003, included 133 operators from five centres (Ontario and British Columbia, Canada and Washington State, USA) involving 728 patients. The resulting Cormack-Lehane (C/L) laryngeal exposure was excellent (1) in 92% of patients and good (2) in 7% of patients. The GVL provided a comparable or superior view in the 133 patients in whom both the GVL and the direct laryngoscope (DL) were used. Among the 35 patients with a C/L grade ≥ 3 view with the DL, the view improved to a C/L grade 1 view in 24 patients and a C/L grade 2 view in three patients. Tracheal intubation with the GVL was successful in 96.3% of patients and failed in 3.7%. Fifty-four percent of the failed intubations occurred despite achieving a C/L grade 1 view and resulted from the inability to direct the endotracheal tube toward a clearly seen larynx. The GVL consistently yielded a comparable or superior glottic view compared with the DL despite the operators’ limited or lack of prior experience with the device. Successful intubation was typically achieved even when direct laryngoscopy was predicted to be moderately or considerably difficult. Not only was the GVL a novice-friendly device, this novel study also suggested that a video laryngoscope might provide superior performance when compared with the DL, particularly in patients in whom the DL provided a poor laryngeal view.

Anesthetic implications of infants with mandibular hypoplasia treated with mandibular distraction osteogenesis

SummaryObjectives To document the incidence of difficult intubation following mandibular distraction osteogenesis (MDO) in children with severe mandibular hypoplasia. Background Syndromes associated with significant mandibular hypoplasia, especially Pierre Robin sequence, provide a challenge in airway management both in and out of the operating room. Mandibular advancement using mandibular distraction osteogenesis devices has been used in infants in an attempt to reduce the incidence of acute life-threatening airway obstruction. Whether MDO also reduces the incidence of difficult intubation has not been adequately described. Methods A retrospective chart review of 51 infants with upper airway obstruction secondary to mandibular hypoplasia who required MDO between January 2002 and 2012. The primary outcome was the incidence of difficult or failed intubation. Secondary outcomes were the relationship between syndrome type and the incidence of difficult intubation. Results Fifty-one PRS infants were identified. Twenty-eight patients had isolated PRS, six had syndromic PRS, seven had Treacher Collins syndrome, and 10 had another coexisting syndrome. Prior to mandibular distraction osteogenesis (MDO), the incidence of difficult intubation was 71%, with the highest incidence in patients with Treacher Collins syndrome (100%), sPRS syndrome (100%), and PRS (65%). Following MDO, the incidence of difficult intubation was 8.3%. The difference was statistically significant for all patients (Kruskal–Wallis rank test P = 0.0001) those with isolated PRS (P = 0.0001), syndromic PRS (P = 0.0023), and other syndromes (P = 0.0002), but not for Treacher Collins syndrome (P = 0.21). Three patients had pre existing tracheostomies. Conclusions In a select group of infants with severe upper airway obstruction who have failed nonsurgical airway interventions, mandibular distraction osteogenesis reduces the incidence of difficult mask ventilation and difficult intubation. We were not able to compare the improvement in airway management to a comparable group of PRS infants who did not undergo surgical intervention. The improvement in laryngeal view was most marked for infants with isolated PRS but no significant benefit was demonstrated in infants with TCS.

External laryngeal manipulation done by the laryngoscopist makes the best laryngeal view for intubation.

Purpose:External laryngeal manipulation (ELM) is used to get better laryngeal view during direct laryngoscopy. This study was designed to test the hypothesis that ELM done by the intubating anesthetist (laryngoscopist) offers the best laryngeal view for tracheal intubation.Materials and method:A total of 160 patients underwent different surgical procedures were included in this study. Percentage of glottic opening (POGO) score and Cormack and Lehane scale were used as outcome measures for comparison between different laryngoscopic views. Four views were described; basic laryngoscopic view and then views after ELM done by the assistant, by the laryngoscopist and finally by the assistant after the guidance from the laryngoscopist respectively. The last three views compared with the basic laryngoscopic view.Results:ELM done by the laryngoscopist or by the assistant after guidance from the laryngoscopist showed significant improvement of Cormack grades and POGO scores compared with basic laryngoscopic view. Number of patients with Cormack grade1 increased from 39 after direct laryngoscopy to 97 and 96 patients (P < 0.001 by Fisher's exact test), after ELM done by the laryngoscopist and that done by the assistant after guidance from the anesthetist respectively. Furthermore, the number of patients with POGO scores of 100% increased from 39 after direct laryngoscopy to 78 and 61 (P < 0.01) patients after ELM done by the laryngoscopist and that done by the assistant after guidance from the anesthetist respectively.Conclusion:It appeared from this study that ELM done by the anesthetist makes the best laryngeal view for tracheal intubation.