Comparison of BlockBuster laryngeal mask with Air-Q intubating laryngeal airway as a conduit for fiber-optic guided intubation in children: A prospective randomized controlled study.

BACKGROUND: The pediatric sizes of BlockBuster supraglottic airway (SGA) have been introduced recently. Its efficacy as a conduit for endotracheal intubation in children has not been assessed. Newer devices are often compared with Air-Q SGA to assess their intubating capability. AIMS: The primary objective was to compare the time taken for fiber-optic-guided intubation through the BlockBuster and the Air-Q SGAs. METHODS: Sixty children aged 6 months to 12 years with normal airways were randomized into two groups: Air-Q SGA (Group A) and Blockbuster SGA (Group B). After administration of general anesthesia, an appropriately sized SGA was inserted. The time taken for fiber-optic-guided intubation through the SGA, success, ease, and time for SGA insertion and removal were noted. The glottic view was graded by fiber-optic bronchoscopy. RESULTS: Demographic parameters were comparable. The time to intubate with the BlockBuster 62.40 ± 17.2 s was comparable to the Air-Q 60.8 ± 18.5 s (mean difference 1.6 s, 95% CI -7.65 to10.85; p = .73). The average time for SGA insertion in BlockBuster and Air-Q was 14.57 ± 3.2 s and 16.67 ± 5.39 s, respectively (mean difference -2.1, 95% CI -4.39 to 0.19 s; p = .07). The first-attempt intubation success and overall intubation success rates were comparable in both groups, 96.7% and 100%, respectively. In Group B, 25/3/1/1/0 cases had a glottic view grade of 1/2/3/4/5, respectively. In Group A, 23/3/2/2/0 cases had grade of 1/2/3/4/5 glottic views respectively. The average time to SGA removal was comparable between the BlockBuster (20.17 ± 5.8 s) and the Air-Q (22.5 ± 12.8 s) groups (mean difference -2.3 s, 95% CI -7.5 to 2.82 s; p = .37). None of the children had any perioperative complications. CONCLUSION: BlockBuster SGA may be a useful alternative to Air-Q for SGA-assisted, fiber-optic-guided tracheal intubation in children.

Assessment of scoring systems to describe the position of tracheostomy tubes within the airway - the lunar study.

BACKGROUND: Malposition of tracheostomy tubes is difficult to detect at the bedside and may contribute to eventual device misplacement. Endoscopic examination can be undertaken via tracheoscopic (T-view) or trans-laryngeal (L-view) approach, offering more precise detail regarding positioning within the airway. The aims of this study were to evaluate inter-rater agreement between bespoke T and L view scoring systems and subsequently whether T-views could predict L-views. METHODS: Adult intensive care unit patients with percutaneous or surgical tracheostomies were included and paired T and L-views of their tracheostomy tube within the airway were taken on up to four occasions. Images were later scored by five independent raters using bespoke scoring systems. The primary outcome was to determine the T and L view scoring system with the best inter-rater agreement, defined by weighted kappa and intra-class correlation coefficients. The secondary outcome was to assess agreement between T and L-view scoring systems. RESULTS: Seventy-one T-views and 43 L-views were obtained from a total of 20 patients. Images were scored by five raters, resulting in 355 T-view scores, 215 L-view scores and 215 paired T and L-view scores for comparison. There was good inter-rater agreement (highest T-view k = 0.84, L-view k = 0.72). There was poor agreement between T and L-view scores for each of the paired images (highest k = 0.25) although extreme-to-extreme misclassification rates remained acceptable. CONCLUSIONS: Whilst our data demonstrated good inter-rater agreement between scoring systems, it is not possible to reliably predict the T-view orientation and position of a tracheostomy tube within the airway from the paired L-view. CLINICAL TRIAL REGISTRATION: NCT01356719.

Evaluation of six videolaryngoscopes in 720 patients with a simulated difficult airway: a multicentre randomized controlled trial.

BACKGROUND: Videolaryngoscopes are aggressively marketed, but independent evaluation in difficult airways is scarce. This multicentre, prospective randomized controlled trial evaluates six videolaryngoscopes in patients with a simulated difficult airway. METHODS: With ethics committee approval and written informed consent, 12 senior anaesthetists intubated the trachea of 720 patients. A cervical collar limited mouth opening and neck movement, making intubation difficult. We evaluated three unchannelled (C-MAC™ D-blade, GlideScope™, and McGrath™) and three channelled videolaryngoscopes (Airtraq™, A.P. Advance™ difficult airway blade, and KingVision™). The primary outcome was first-attempt intubation success rate. Secondary outcomes included overall success rate, laryngeal view, intubation times, and side-effects. The primary hypothesis for every videolaryngoscope was that the 95% confidence interval of first-attempt success rate is ≥90%. RESULTS: Mouth opening was decreased from 46 (sd 7) to 23 (3) mm with the cervical collar. First-attempt success rates were 98% (McGrath™), 95% (C-MAC™ D-blade), 87% (KingVision™), 85% (GlideScope™ and Airtraq™), and 37% (A.P. Advance™, P<0.01). The 95% confidence interval of first-attempt success rate was >90% only for the McGrath™. Overall success, laryngeal view, and intubation times differed significantly between videolaryngoscopes (all P<0.01). Side-effects were minor. CONCLUSIONS: This trial revealed differences in the performance of six videolaryngoscopes in 720 patients with restricted neck movement and limited mouth opening. In this setting, first-attempt success rates were 85-98%, except for the A.P. Advance™ difficult airway blade. Highest success and lowest tissue trauma rates were achieved by the McGrath™ and C-MAC™ D-blade, highlighting the importance of the videolaryngoscope blade design. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: identifier NCT01692535.

Fracture of Laryngeal Mask Airway during General Anesthesia / 대한마취과학회지

Laryngeal mask airway (LMA) is an adjunctive airway device composed of a tube with a cuffed mask-like projection on the distal end, which is more practical than a face mask and less invasive than an endotracheal tube. It has the great economical advantage of being reusuable. Even though the LMA withstands a large number of sterilization cycles without undergoing damage, these sterilization cycles make the tear strength of the LMA lower. And it can be easily damaged during anesthesia or sterilization. We report a case of a fracture of the LMA during anesthesia probably caused by teeth as well as prolonged and repeated use.

Clinical Application of Laryngeal Mask Airway in Cesarean Section / 대한마취과학회지

BACKGROUND: Laryngeal mask airway (LMA) is a useful instrument for routine anesthesia. It permits spontaneous or positive pressure ventilation but its use in obstetric anesthesia has not been described. In this study, we evaluated the effectiveness and the side effects of the LMA during elective cesarean sections. METHODS: Institutional approval and patients' permission were obtained. One thousand sixty-seven patients scheduled for elective an cesarean section, that have been NPO for more than 6 (6-48) hours were evaluated. They were premedicated with an H2 receptor blocker (ranitidine 50 mg i.m.) 1 hour before the operation. They were anesthetized with penthotal sodium (3-4 mg/kg), vecuronium (1 mg/10 kg i.m.) and then a 3 or 4 LMA was inserted after the mask ventilation with 100% oxygen for 1 min. The cuff was inflated with air 15.3 +/- 2.6 ml. On auscultation, air entry was good in both lungs. Anesthesia was maintained by 50% oxygen in N2O with 0.7 - 1.0% enflurane. Analgesics (tramadol 30 mg i.v.) was given incrementally after delivery of the baby. Manual assisted ventilation was used throughout the procedure. The number of insertion attempts, cuff volume and the incidences of complications were evaluated. RESULTS: In 1051 patients, the LMA was inserted on the first attempt. In 16 patients more than 2 attempts were needed and change to endotracheal intubation were needed in 7 cases. The mean cuff volume was 15 +/- 2.6 ml at insertion and increased to 18.5 +/- 3.2 ml after removal. The average airway pressure was 20 cmH2O during positive pressure ventilation, above that pressure air leakage was detected in 16 cases. Complications noted were mild sore throat in 5 cases, and blood tinged after removal of LMA in 3 cases but gastric distention was not detected. No incidence of aspiration was noted. CONCLUSIONS: In this study, the LMA proved to be a useful tool for the management of patients presenting for elective an cesarian section. There is the remote possibility of aspiration which did not happen in our study.

A Comparison of Two Types of Tracheal Tube for Use in Intubating Laryngeal Mask Airway Assisted Blind Orotracheal Intubation / 대한마취과학회지

BACKGROUND: The conventional laryngeal mask airway (LMA) has been used to facilitate blind tracheal intubation in numerous situations where laryngoscopy and conventional intubation has been difficult, but it has the disadvantage that its airway tube is too long and narrow for intubation. The intubating laryngeal mask airway (ILM) has been specifically designed to increase the success rate of blind intubation. A specially constructed ILM tracheal tube is available for use with the ILM, But this tube is in short supply and expensive. Thus, this study was performed to compare the success rate and time of blind intubation through ILM with reinforced tracheal tube or specially-designed tracheal tube, and to assess the use of reinforced tracheal tube as a substitute for specially-designed tracheal tube. METHODS: After acquiring informed consent, 60 ASA grade 1 or 2 patients undergoing anesthesia for elective surgical procedures who normally required tracheal intubation were randomized into two groups. In group 1 (n = 30), the patients were intubated with a specially-designed tracheal tube through ILM. In group 2 (n = 30), reinforced tracheal tubes were used. The patients were induced and relaxed with an iv injection of thiopental sodium, fentanyl-ketamine-midazolam mixture and vecuronium. When an adequate level of anesthesia was achieved, the ILM was inserted. After adequate ventilation was confirmed, blind tracheal intubation with either of the two types of tracheal tubes through the ILM was attempted. Then we recorded success rate, intubation time and adjusting maneuvers. RESULTS: The ILM was successfully inserted at first attempt in 59/60 (98%) patients, but in 1 patient, adequate ventilation was not acheived. The success rate of tracheal intubation was 27 (93%) in group 1 and 28 (93%) in group 2. In group 1, 21 (72%) patients were successfully intubated on the first attempt, 1 (4%) patient on the second attempt, and 5 (17%) patients on the third attempt. In group 2, 20 (67%) patients were successfully intubated on the first attempt, 2 (6%) patients on the second attempt, and 6 (20%) patients on the third attempt. The mean time taken for intubation was 116.9 sec in group 1 and 122.3 sec in group 2. CONCLUSIONS: The authors conclude that the reinforced tracheal tube can be substitute for a specially- designed tracheal tube.

Endotracheal Intubation through the Intubating LMA / 대한마취과학회지

BACKGROUND: The fundamental responsibility of an anesthesiologist is to maintain adequate ventilation and to supply oxygen in the face of unexpected difficulties with tracheal intubation. The laryngeal mask airway (LMA) has been used as a ventilatory device familiarly for routine or difficult intubation but it has been hard to intubate with it the larger than 6 mm internal diameter (ID) endotracheal tube (ET). The intubating LMA is a new prototype of the LMA; it is partey composed of an anatomically curved rigid airway tube of ID 13 mm for larger ET tube insertion (such as ID 9.0 mm) into a 15 mm connector at its outer end which is fixed permanently to a laryngeal mask. This study was performed to evaluate the technique and facility of the intubating LMA as an apparatus for endotracheal intubation when used by an inexperienced anesthesiologist. METHODS: With informed consent, 43 patients of ASA physical status I or II were selected. Either lubricated polyvinyl chloride or an armored wire tube of ID 7.0 or 7.5 mm was intubated through the No. 4 or 5 intubating LMA. During this procedure, we observed the technical method and success rate, and recorded systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) changes. 24 hours after each operation, we observed subjective symptoms such as sore throat, hoarseness, and difficult in swallowing. RESULTS: The success rate of intubating LMA insertion was as follows: 33 (77%) patients were successed on first attempt, 6 (14%) patients on second attempt, 4 (9%) patients on third attempt. The insertion of the intubating LMA was carried out facilely without another maneuver such as neck extension or tongue expulsion. The success rate of tracheal intubation was 86.1%. In 32 (74.5%) patients there was easy intubation, but 5 (11.6%) patients required more adjustment and the failure rate with them was 6 (13.9%). SBP, DBP were only increased by endotracheal intubation through the intubating LMA, but HR was significantly increased during both insertion and intubation (p < 0.05). Postoperative sore throat was complained of in 11 patients; hoarseness in 1 patient. CONCLUSIONS: Insertion of the intubating LMA is facile due to the absence of need for the maneuvers of neck motion or tongue expulsion. The intubating technique through the intubating LMA is a relatively rapid and easy method, but it requires technical experience which in some cases is lacking in inexperienced anesthesiologists.

Endotracheal Intubation through the Intubating LMA / 대한마취과학회지

BACKGROUND: The fundamental responsibility of an anesthesiologist is to maintain adequate ventilation and to supply oxygen in the face of unexpected difficulties with tracheal intubation. The laryngeal mask airway (LMA) has been used as a ventilatory device familiarly for routine or difficult intubation but it has been hard to intubate with it the larger than 6 mm internal diameter (ID) endotracheal tube (ET). The intubating LMA is a new prototype of the LMA; it is partey composed of an anatomically curved rigid airway tube of ID 13 mm for larger ET tube insertion (such as ID 9.0 mm) into a 15 mm connector at its outer end which is fixed permanently to a laryngeal mask. This study was performed to evaluate the technique and facility of the intubating LMA as an apparatus for endotracheal intubation when used by an inexperienced anesthesiologist. METHODS: With informed consent, 43 patients of ASA physical status I or II were selected. Either lubricated polyvinyl chloride or an armored wire tube of ID 7.0 or 7.5 mm was intubated through the No. 4 or 5 intubating LMA. During this procedure, we observed the technical method and success rate, and recorded systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) changes. 24 hours after each operation, we observed subjective symptoms such as sore throat, hoarseness, and difficult in swallowing. RESULTS: The success rate of intubating LMA insertion was as follows: 33 (77%) patients were successed on first attempt, 6 (14%) patients on second attempt, 4 (9%) patients on third attempt. The insertion of the intubating LMA was carried out facilely without another maneuver such as neck extension or tongue expulsion. The success rate of tracheal intubation was 86.1%. In 32 (74.5%) patients there was easy intubation, but 5 (11.6%) patients required more adjustment and the failure rate with them was 6 (13.9%). SBP, DBP were only increased by endotracheal intubation through the intubating LMA, but HR was significantly increased during both insertion and intubation (p < 0.05). Postoperative sore throat was complained of in 11 patients; hoarseness in 1 patient. CONCLUSIONS: Insertion of the intubating LMA is facile due to the absence of need for the maneuvers of neck motion or tongue expulsion. The intubating technique through the intubating LMA is a relatively rapid and easy method, but it requires technical experience which in some cases is lacking in inexperienced anesthesiologists.

The Effect of Cuff Volume of Laryngeal Mask Airway on Cuff Pressure and Ventilation / 대한마취과학회지

BACKGROUND: The cuff inflation of laryngeal mask airway (LMA) with excessive volume of air may injure soft tissue and nerves around hypopharynx because of high cuff pressure. But it is not well known about adequate cuff volume of LMA. The cuff inflation of LMA in hypopharynx accomodate pharynx, so various injection volume may differ in sealing effect. This may influence ventilation. This study was proposed to investigate the effect of cuff volume on cuff pressure and ventilation when LMA inserted. METHODS: Fifteen male patients were inserted with #4 LMA, fifteen female patients were inserted #3 LMA. For male patients, 10, 20, 30 and 40 ml of air were injected into cuff of LMA and 10, 15, 20 and 25 ml for female patients. Cuff pressure, minute ventilation and airway pressure were randomly measured. RESULTS: Volume of injected into cuff and cuff pressure of LMA were closly related. But minute ventilation and airway pressure were not related with injected air volume of LMA. CONCLUSION: Excessive volume of air injected to LMA cuff was not beneficial to ventilation. So minimal sealing cuff volume under maximal recommended volume of LMA may reduce the incidence of complications associated with high cuff pressure.