Tracheal intubation

Tracheal intubation is the act of placing a tube into the trachea thus enabling oxygen delivery and carbon dioxide removal. Intubation is the most reliable method of maintaining an airway under anaesthesia, and for protecting against aspiration of stomach contents. Traditionally, intubation is achieved by direct visualization of the glottis, but indirect laryngoscopy (via a videolaryngoscope) has become a common alternative. Prior to embarking upon intubation, a thorough patient history and examination must be undertaken by the laryngoscopist; equipment must be prepared and checked; a trained assistant present; and an experienced anaesthetist available in case assistance is required. Once the endotracheal tube has been placed, correct positioning must be confirmed via both clinical examination and monitoring, which must include capnography. Tracheal intubation is a procedure that should only be undertaken by trained operators and is not without risk. It is important to note that it is failure to oxygenate patients rather than failure to intubate that ultimately leads to serious morbidity and mortality. The Difficult Airway Society has produced guidelines on how to manage unanticipated difficulty in tracheal intubation; it is essential that every practitioner trained to intubate patients is familiar with these algorithms and the key principles of safe airway management.     

Tracheal intubation

Tracheal intubation is the placement of a tube into the trachea. It provides the gold standard for airway protection ensuring the trachea and lungs are protected from the aspiration of stomach contents. The tube can be used for ventilation permitting oxygen delivery and the removal of carbon dioxide; it also has a role in delivering drugs. If the tracheal tube is misplaced and not recognized, then hypoxia will occur which may be fatal.Tracheal intubation was first recorded in 1543, but few advances were made until the First World War when its importance was recognized. Sir Ivan Whiteside Magill was predominantly involved in the development of tracheal intubation and he designed several pieces of equipment we still use in our clinical practice today.Prior to intubation the required equipment should be assembled and checked and the indication for tracheal intubation confirmed. An experienced and trained assistant is required and an anaesthetist with advanced airway skills should be available. Following tracheal intubation, correct placement of the tube should be confirmed by clinical signs and capnography. The tube should be carefully secured to avoid displacement.     

Tracheal intubation

Tracheal intubation is the placement of a tube into the trachea. It provides the gold standard for airway protection ensuring the trachea and lungs are protected from the aspiration of stomach contents. The tube can be used for ventilation permitting oxygen delivery and the removal of carbon dioxide; it also has a role in delivering drugs. If the tracheal tube is misplaced and not recognized, then hypoxia will occur which may be fatal.Tracheal intubation was first recorded in 1543, but few advances were made until the First World War when its importance was recognized. Sir Ivan Whiteside Magill was predominantly involved in the development of tracheal intubation and he designed several pieces of equipment we still use in our clinical practice today.Prior to intubation the required equipment should be assembled and checked and the indication for tracheal intubation confirmed. An experienced and trained assistant is required and an anaesthetist with advanced airway skills should be available. Following tracheal intubation, correct placement of the tube should be confirmed by clinical signs and capnography. The tube should be carefully secured to avoid displacement.     

Die Kehlkopfmaske bei schwieriger Intubation

Objective. The laryngeal mask airway (LMA) was prospectively used in patients who were difficult to intubate to evaluate whether it improves ventilation compared to a face mask, facilitates fibreoptic intubation, and how often blind intubation would be possible. Methods. In a university hospital, 30 patients who were difficult to intubate (35 operative procedures) and 50 normal subjects were investigated; 23 patients had had radical resection of a facial tumor with irradiation at a previous time and 7 could not be intubated conventionally (grade 3 and 4 visibility of the larynx according to Cormack [14]). Blind intubation was attempted with a bent bougie, a 6.0-mm uncuffed tube, or a straight bougie. Results. Insertion of the LMA was possible in all except 1 patient with a mouth opening of 1?cm. Ventilation via the LMA was always excellent and, for tumor patients, superior to a face mask. In tumor patients, leak pressure was higher than in patients with normal cervical anatomy either with or without difficult intubation conditions (25.2±7.9, P<0,05, vs. 20.8±4.4 vs. 20.6±4.9?cmH₂O; n.s.; Fig.?2). Fibreoptic intubation through the LMA was successful in all cases and easier than via a nasal or oral route. Blind intubation was successful in 22% of difficult to intubate patients and 19% of normals, mainly using a 6.0?mm uncuffed endotracheal tube. Substitution of an uncuffed oral tube inserted via the LMA by a nasal endotrachel tube using a reinforced stomach tube is described (Fig.?4). Conclusion. The LMA improves ventilation, facilitates fibreoptic intubation, and offers the possibility for blind endotracheal intubation in difficult to intubate patients. Blind intubation though the LMA has to be practised extensively to have a high sucess rate. The LMA represents an additional aid for the anaesthetic management of patients who are difficult to intubate.     

Airway management after failure to intubate by direct laryngoscopy: outcomes in a large teaching hospital

PURPOSE: The purpose of this single-centre database review was to establish the incidence of failure to intubate by direct laryngoscopy, to measure morbidity and mortality associated with this event, and to examine the use and efficacy of alternative airway devices. METHODS: Difficult intubation via direct laryngoscopy at Mayo Clinic Rochester is recorded in an electronic database using a functional classification: 0 = no difficulty; 1 = mild to moderate difficulty; and 2 = severe difficulty often requiring a change in intubation technique. Using this database, the total number of intubations was determined for a selected review period and the incidence of failure to intubate by direct laryngoscopy was established. Abstraction of chart data allowed for determination of associated morbidity and mortality, success of alternative airway devices, and case cancellation rate. RESULTS: During the period from August 1, 2001 through December 31, 2002, 37,482 patients underwent general anesthesia with attempted direct laryngoscopy. One hundred sixty-one patients (0.43%) could not be intubated by direct laryngoscopy alone. Morbidity associated with difficult intubation included soft tissue/dental damage (n = 8), intraoperative cardiac arrest (n = 1), and possible aspiration (n = 1). Three patients required intensive care unit admission. There was no associated mortality. The most commonly used alternative airway device was the flexible fibreoptic scope. Five case cancellations resulted from failure to intubate with alternative devices. CONCLUSION: The rate of unexpected failure to intubate by direct laryngoscopy is essentially unchanged from earlier studies. While morbidity was low, continued education and early use of alternative difficult airway devices may further limit complications associated with this event.     

Fiberoptic intubation via laryngeal mask airway under general anesthesia in the patients with halo vest

Since 1991, we gave anesthesia to 155 patients with halo vest. All of 128 whose airways could be kept patent by laryngeal mask airway (LMA) were successfully intubated fiberoptically via LMA using the tube exchange catheter under general anesthesia. Four patients developed airway obstruction during the induction of anesthesia, two of whom were awakened and subsequently intubated by awake fiberoptic intubation. In one patient LMA could keep the airway patent. In the other patient, cervical immobilization by halo device was released and the intubation was performed with a laryngoscope. For 8 patients, awake fiberoptic intubation was chosen from the preoperative evaluation of the positioning of head and neck. Fifteen patients were intubated with a laryngoscope without trying LMA fiberoptic intubation. No patient developed neurological injury attributed to the intubation. LMA fiberoptic intubation has several advantages. Patients do not feel discomfort under general anesthesia. Ventilation is kept continued until LMA is removed. Even less experienced residents can intubate easily and safely without assistance. However, we must carefully diagnose and select the patient whose airway can be kept patent under general anesthesia. The motionless pictures of the intubation procedures can be seen on the web site: www.hosp.go.jp/~kobe/.     

Large goitre causing difficult intubation and failure to intubate using the intubating laryngeal mask airway: lessons for next time

A 63-yr-old woman was anaesthetized for sub-total thyroidectomy. The thyroid gland was large, deviating the trachea to the right and causing 30% tracheal narrowing at the level of the suprasternal notch. Mask ventilation was easy but laryngoscopy was Cormack and Lehane grade 3. Despite being able to see the tip of the epiglottis, tracheal intubation was impossible. An intubating laryngeal mask was inserted and although the airway was clear and ventilation easy, it was not possible to intubate the trachea either blindly or with the fibreoptic bronchoscope. Tracheal intubation was eventually achieved using a 6.5- mm cuffed oral tracheal tube via a size 4 laryngeal mask under fibreoptic control. We describe the case in detail and discuss the use of the intubating laryngeal mask, its potential limitations and how to optimize its use in similar circumstances.      

A comparative study of tracheal intubation using an intubating laryngeal mask (Fastrach) alone or together with a lightwand (Trachlight)

Study Objective: To determine if the Trachlight^TM lightwand can facilitate Fastrach^TM intubation by guiding the tip of the endotracheal tube into the trachea.

Design: Open-label, prospective, randomized, comparative study.

Setting: General operating suites of a tertiary teaching hospital.

Patients: 172 elective surgical patients requiring general anesthesia with endotracheal intubation.

Interventions: With general anesthesia, the Fastrach™, which is a new intubating laryngeal mask airway, was inserted into the oropharynx. Ventilation was ensured before the insertion of an endotracheal tube via the Fastrach™. Tracheal intubation was then performed randomly (coin toss) using either the endotracheal tube alone (Fastrach™ group), or endotracheal tube with the Trachlight, a lightwand (Fastrach/Trachlight™ group). The time to place the Fastrach™ and endotracheal tube, to remove the Fastrach™, and the total time to intubate were recorded. The number of attempts, failures, trauma, sore throats, and hemodynamic changes were also recorded. Data were analyzed using unpaired t-test, ANOVA with repeated measures, or Chi-squares contingency table where appropriate.

Measurements and Main Results: Although there were no differences in the times to place the Fastrach™, and endotracheal tube, the hemodynamic changes, and postoperative complications, there were significantly more attempts and failures in the Fastrach™ group compared to the Fastrach™/Trachlight™ group. There were no differences in the incidence of sore throat and trauma in between the groups.

Conclusions: Although tracheal intubation is effective using a Fastrach™ alone (76% success rate), it is more effective when the Fastrach™ is used in conjunction with the Trachlight™ (95%). These results suggest that the lightwand is a useful adjunct for Fastrach™ intubation. However, the role of Fastrach™ intubation together with the Trachlight™ in the management of patients with a potential difficult airway remains to be determined.     

A comparison of fibreoptic‐guided tracheal intubation through the Ambu®Aura‐i™, the intubating laryngeal mask airway and the i‐gel™: a manikin study

We compared the Aura‐i ^? , intubating laryngeal mask airway and i‐gel ^? as conduits for fibreoptic‐guided tracheal intubation in a manikin. Thirty anaesthetists each performed two tracheal intubations through each device, a total of 180 intubations. The median (IQR [range]) time to complete the first intubation was 40 (31–50 [15–162]) s, 37 (34–48 [25–75]) s and 28 (22–35 [14–59]) s for the Aura‐i, intubating laryngeal mask airway and i‐gel, respectively. Tracheal intubation through the i‐gel was the quickest (p < 0.01). Resistance to railroading of the tracheal tube over the fibrescope was significantly greater through the Aura‐i compared with the intubating laryngeal mask airway and the i‐gel (p = 0.001). There were no failures to intubate through the intubating laryngeal mask airway or the i‐gel but six intubation attempts through the Aura‐i were unsuccessful, in five owing to a railroading failure and in one owing to accidental oesophageal intubation. We conclude that the Aura‐i does not perform as well as the intubating laryngeal mask airway or the i‐gel as an adjunct for performing fibreoptic‐guided tracheal intubation.     

The intubating laryngeal mask airway does not facilitate tracheal intubation in the presence of a neck collar in simulated trauma

Tracheal intubation must be performed with great care in the multiply injured patient when it must be assumed that the cervical spine may be damaged. Use of conventional direct laryngoscopy usually requires removal of the neck collar and manual in-line stabilization of the head and neck. The intubating laryngeal mask (ILMA) has been designed to facilitate tracheal intubation in the neutral position. We used the ILMA to intubate the trachea in 10 patients wearing a neck collar and with cricoid pressure applied in a simulated trauma scenario. The ILMA was difficult to insert and ventilation proved difficult. In only two patients was intubation successful. These problems were probably caused by the neck collar strap under the chin lifting up and tipping the larynx anteriorly. On the basis of these findings, ILMA use in a subject wearing a neck collar cannot be recommended.      

Erste Erfahrungen mit der Intubationslarynxmaske

Objective: We report our initial experience with an improved model of the laryngeal mask airway, the intubating laryngeal mask airway (ILMA, commercial name Fastrach), which was designed by A.I.J. Brain to improve blind endotracheal intubation through a laryngeal mask. Methods: In the ILMA, a number of construction details were newly designed compared to a standard laryngeal mask airway (SLM): 1) the angle between the shaft and the mask plane is changed, and also the radius of the shaft, 2) the internal diameter of the shaft is increased to allow the passage of an 8.0 mm cuffed endotracheal tube, resulting in an outer diameter of 2.0 cm, 3) a stable rubber lip (epiglottic elevating bar) is incorporated instead of the gills to clear the epiglottis out of the lumen during the passage of the endotracheal tube, 4) the shaft is manufactured out of stainless steel covered by silicone with a handle attached for more precise guidance. We prospectively used the ILMA in 80 patients for blind intubation. 51 had normal anatomy (group I), 19 were difficult to intubate (Cormack grade 3–4; group II), 18 had a reduced mouth opening (≤2.5 cm awake; group III), 8 of them also were difficult to intubate. Results: Insertion of the ILMA and ventilation was possible in all patients but one with a mouth opening of 1.3 cm during anaesthesia. 4 patients with difficult intubation and one with normal anatomy could not be ventilated with a face mask but could be ventilated with the ILMA. Blind intubation was successful in 69 out of 80 patients (global success rate 87%; group I: 84%; II: 95%; III: 83%), in 38 during the first attempt (initial success rate 48%; group I: 45%; II: 63%; III: 44%), showing no difference for patients with normal anatomy, difficult intubation or reduced mouth opening. For 82 successful intubations, 157 intubation attempts were performed (success rate per attempt 52%; group I: 48%; II: 67%; III: 54%). Success rate per attempt decreased to 42%, if intubation was not successful during the first attempt (106 intubation attempts resulting in 44 successful intubations, including 31 intubation attempts for 11 failures; group I: 35%; II: 56%; III: 38%). Intubation through the ILMA was not possible in 11 patients (14%). Failures to intubate were caused by a reduced mouth opening in 1 patient, an unsuited endotracheal tube in 1 patient, a wrong size of the ILMA may have been the cause in 6 patients, in the remaining 3, lacking personal skill may have been responsible. Endotracheal tubes suited to be used with the ILMA are straight or preformed Woodbridge tubes, whereas standard plastic tubes are too stiff. Manouvres facilitating blind intubation though the ILMA were careful alignment of the ILMA with the handle, an up and down manouvre, rotation of the tube or head movements. Conclusion: The ILMA improved ventilation compared to a face mask and almost doubled the success rate of blind intubation compared to a SLM in our hands in a variety of intubation situations. The ILMA has the potential to be useful in difficult to intubate patients – except those with cervical pathology – or in emergency medicine. Handling can be trained during every day routine. Experienced judgement of definite endotracheal tube placement is mandatory.     

Maskenbeatmung als Rückzugsstrategie zur endotrachealen Intubation

The goal of ventilation in an unprotected airway is to optimize oxygenation and carbon dioxide elimination of the patient. This can be achieved with techniques such as mouth-to-mouth ventilation, but preferably with bag-valve-mask ventilation. Securing the airway with an endotracheal tube is the gold standard, but excellent success in emergency airway management depends on initial training, retraining, and actual frequency of a given procedure in the routine. "Patients do not die from failure to intubate; they die from failure to stop trying to intubate or from undiagnosed oesophageal intubation" (Scott 1986). Therefore, adequate face mask ventilation has absolute priority in airway management by an unexperienced rescuer. During ventilation of an unprotected airway, stomach inflation and subsequent severe complications may result. Careful ventilation can be performed with low inspiratory pressure and flow, and subsequently with a low tidal volume at a high inspiratory fraction of oxygen. This could be a strategy to achieve more patient safety.     

Fibreoptic nasal intubation in children with anticipated and unanticipated difficult intubation

The establishment of a tracheal airway with direct laryngoscopy can be either a very difficult or an impossible task in children with congenital or acquired facial malformations. Out of 46 patients categorized as difficult tracheal intubation, fibreoptic laryngoscopy was used successfully in 44 children anaesthetized by mask with sevoflurane and oxygen or by an intravenous infusion of propofol and mask oxygenation. There were two failures (4.3%). One was due to excessive bleeding and secretions produced by the multiple attempts to intubate with direct laryngoscopy and the other failure in a patient with Pierre Robin syndrome and very small nasal passages that precluded the introduction of the endoscope. Fibreoptic laryngoscopy was successful in 37 cases (80.4%) on the first attempt to intubate and in seven (15.2%) on a second or third attempt. We conclude that fibreoptic laryngoscopy in anaesthetized children with difficult anticipated or unanticipated tracheal intubation in trained hands is a safe technique that can be lifesaving. Therefore, we urge all anaesthesia trainees to become proficient in fibreoptic tracheal intubation.     

TRACHEAL INTUBATION IN A MANNIKIN: COMPARISON OF THE BELSCOPE WITH THE MACINTOSH LARYNGOSCOPE

Tracheal intubation carries a risk of accidental oesophagealintubation; this is increased with inexperienced trainees, andin patients with a difficult airway. The recent introductionof an angulated laryngoscope, the Belscope, may permit a betterview of the vocal cords and increase the accuracy of orotrachealintubation. To determine how easy it is to learn to use theBelscope compared with the traditional Macintosh laryngoscope,a group of medical students attempted to intubate a mannikinwhich had been modified to simulate a difficult intubation.Time to intubation was fast with both laryngoscopes, althoughfaster with the Macintosh, but the Belscope produced an unexpectedgreater incidence of failed intubation. (Br. J. Anaesth. 1993;71: 905–907) ^*Department of Anaesthetics, Portiuncula Hospital, Ballinasloe,Co. Galway, Ireland     

Die schwierige Intubation beim Erwachsenen

Goal of this review. We review the recent literature and our experience in order to determine how one can recognize and handle patients with difficult endotracheal intubation. Definition and incidence.?An intubation is called difficult if a normally trained anesthesiologist needs more than 3 attempts or more than 10 min for a successful endotracheal intubation.“ The incidence of difficult intubation depends on the degree of difficulty encountered showing a range of 1–18% of all intubations to about 2/10000 – 1/million for ?cannot ventilate – cannot intubate“ situations. Three ?cannot ventilate – cannot intubate“ situations are presented that occurred at our institution in the last 10 years out of about 85000 anaesthesias. Preoperative recognition. Intubation will be overtly difficult in patients with a small mouth opening, protruding upper teeth, a stiff neck, engorgement of the tongue, cervical swelling after an operation for a face tumour, or in patients with an unstable cervical spine. In about 50–70%, a difficult intubation can be detected preoperatively in patients with grossly normal cervical anatomy by three indirect signs: if the soft palate cannot be visualized (Mallampati classification), if the inframandibular space is smaller than normal, and if the mobility of the atlanto-occipital joint is reduced to below 15°. It is essential that these indirect parameters be tested preoperatively, especially in patients in whom general anaesthesial is planned for a caesarean section or if an ileus intubation is planned. Handling. General handling of difficult intubation, use of special material including a portable unit, and confirmation of the endotracheal position of an endotrachaeal tube are outlined (CO₂ et, SaO₂, fibreoptic bronchoscopy, direct visualization of the translaryngeal position of the tube). The laryngeal mask airway, transtracheal jet ventilation, and the mini-coniotomy are selectively presented as alternative airways. The American Society of Anesthesiologists' (ASA) difficult airway algorithm is presented. Conclusion. With better preoperative evaluation and clear guidelines and training for difficult intubation anaesthetic morbidity and mortality can be reduced.     

Infraglottic airway devices and techniques

Infraglottic airway management techniques, such as intubation of the trachea with a cuff-sealed endotracheal tube, offer significant advantages for the anaesthetized patient, especially for patients in critical condition.There are numerous ways of intubation of the trachea; the most common and popular is direct laryngoscopy. The variety of laryngoscope blades offers choices to solve difficult intubations, but all different techniques and devices need experience in routine clinical use.In case of failure, unsuccessful attempts to intubate the trachea should be limited to three, in order to use different—e.g. supraglottic or fibreoptic—techniques.Nasotracheal intubation causes an inherent risk of severe epistaxis, which may severely compromise airway management options and endangers the patient's life. Prior to passing the tube through the nose, direct laryngoscopy should be performed to estimate the Cormack–Lehane score.Rigid intubation fibrescopes—as flexible ones—do improve the view of the larynx and permit tracheal intubation with less head and cervical spine movement than direct laryngoscopy. Success with these devices requires considerable experience and clinical practice.The use of retrograde intubation has reduced during recent years, mainly due to the availability of flexible and rigid intubation fibrescopes.The EasyTube—a relatively new device—combines the advantages of both an endotracheal tube with a supraglottic airway device.The Combitube is a well-established emergency airway used widely for solving unanticipated and anticipated difficult airways. International guidelines recommend the use of Combitube following the number of studies and reports associated with its use.     

Difficult airway in a child with spinal muscular atrophy type I

Spinal muscular atrophy (SMA) type I is a relatively common inherited neuromuscular disease of hypotonic newborns, but is not associated with craniofacial abnormalities. There is nothing in the literature about difficult intubation in patients affected by this disease. We report a case of 34-month-old girl with SMA type I who was scheduled for emergency endoscopic laser treatment of tracheal stenosis caused by granulations. Tracheostomy was performed at 17 months of age and before this, the orotracheal tube was changed periodically without difficulty. For this laser treatment, orotracheal intubation was required. Preoperative physical examination revealed micrognathia and class II malocclusion. Opening her mouth was not difficult. Although difficult orotracheal intubation was predictable, we attempted to intubate her trachea as usual, but could not visualize the epiglottis. We decided to proceed with retrograde intubation, one of the standard techniques employed in a child with a difficult airway, via the tracheostome. A feeding nasogastric catheter was used as a guide catheter, and our strategy was successful. In this study we report a case of difficult airway in a child with SMA type I. The relationship between SMA type I with a tracheostome and difficult airway are discussed.     

A case of awake intubation using Pentax-airway scope combined with surface airway anesthesia for two obese patients with cervical spondylosis and for the author himself

We report successful awake intubation using AWS combined with surface anesthesia of the upper airway via nebulizer. The two cases are suitable for awake intubation due to difficult airway. After inhaled lidocaine 4% and nebulized 4 ml, while giving fentanyl i. v, we performed awake intubation. As a preparatory step to the procedure described above, awake intubation was tested on the author himself with only surface anesthesia. The patients and author did not buck during intubation. The present case shows that it is possible to perform awake intubate safely with less stress with the combination of AWS and surface airway anesthesia via nebulizer.     

Fastrach laryngeal mask and difficult intubation

OBJECTIVE: To evaluate the success rate of intubation through the intubating laryngeal mask airway (LMA-Fastrach) in patients with predictive signs of difficult airway or after intubation failure. STUDY DESIGN: Open prospective study. PATIENTS: The study included 33 adults, 21 with predictive signs of difficult airway and 12 after intubation failure. METHODS: After induction of anaesthesia, the intubating LMA was inserted. Proper insertion was confirmed by easy bag ventilation and capnography. Intubation through the intubating LMA was then carried out with an armoured endotracheal tube. If intubation failed, a second attempt was carried out after a gentle manipulation of the intubating LMA. After two attempts, if intubation remained impossible, fibrescopic intubation through the intubating LMA was carried out. In case of failure the usual tracheal intubation algorithms were used. RESULTS: Tracheal intubation through the intubating LMA was successful in all patients, in 32 on the first attempt and in one on the second. Successful tracheal intubation was possible on the first attempt in 25 patients (76%), on the second in four (12%) and after fibrescopic intubation through the intubating LMA in the four remaining (12%). CONCLUSION: The results of this study confirm that tracheal intubation through the intubating LMA can be recommended in patients with a difficult airway, whether foreseen or not.     

Use of GlideScope for double lumen endotracheal tube insertion in an awake patient with difficult airway

There is scientific evidence that an anticipated difficult airway must be managed with the patient being awake. The GlideScope has been proven to be a useful device to intubate the trachea in some instances when difficult airway is present, and particularly in the awake patient. It has also been used for double lumen tube (DLT) in the anaesthetized patient, but its use with DLT in both circumstances, awake patients with difficult airway has not been described.GlideScope enabled us to achieve accurate local anesthetic spraying and a successful endotracheal intubation with a double lumen tube (DLT) in an awake patient with predicted difficult airway and bronchoaspiration risk. Different ways to resolve cases like this can be found in the anesthetic literature, but we think this could be another option to bear in mind. We also describe a new variation in the maneuver of introducing a DLT into the trachea under GlideScope view as DLT presents with some difficulties when introduced under normal circumstances.This option could add some risk for the patients when used in inexperienced hands and there is not sufficient scientific evidence in the literature to recommend it for all cases.