Tamao Iwagaki

Approach combining the airway scope and the bougie for minimizing movement of the cervical spine during endotracheal intubation.

Background:The Airway Scope (AWS, AWS-S100; Hoya-Pentax, Tokyo, Japan), a recently introduced video laryngoscope, has been reported to reduce movement of the cervical spine during intubation attempts in comparison with conventional laryngoscopes. Use of the bougie as an aid for the AWS may cause further reduction. The authors compared cervical spine movement during intubation with the AWS with and without a bougie. Methods:Thirty patients without cervical spine abnormality were randomized into two groups: intubation with AWS only and intubation with the AWS and the bougie. The cervical spine motion between the occiput (C0) and the fourth cervical vertebra (C4) was observed fluoroscopically, and change in movement between adjacent vertebrae created by each intubation method was compared. Time to intubation was also measured. Results:Laryngoscopy with the AWS produced extension of the cervical spine segments assessed (C0-4). Median extension angle of the C0-4 during intubation using the AWS was reduced from 16.0 degrees without the bougie to 6.5 degrees with the bougie (P < 0.01). There was no significant difference in time to intubation between them. Conclusions:Use of the bougie resulted in significantly reduced extension of the cervical spine during intubation attempt with the AWS in patients with a normal cervical spine.

The sniffing position provides greater occipito-atlanto-axial angulation than simple head extension: a radiological study.

PurposeWhile the anatomic sniffing position has traditionally been considered the standard head and neck position for laryngoscopy, recent evidence suggests that the sniffing position provides no significant advantage over simple head extension. To establish if the sniffing position provides an anatomic advantage, we compared the occipito-atlanto-axial extension angle, a key determinant for obtaining a good laryngeal view during laryngoscopy, in simple head extension and sniffing positions.MethodsThirty volunteers with normal cervical spines were studied. Radiological examinations of the lateral cervical spine were taken and compared in each of the following three positions for each subject: neutral position (flat on the table with no pillow and without head extension or flexion); simple head extension (head maximally extended without a pillow); and the sniffing position (head extension with cervical flexion obtained by 7 cm occipital elevation).ResultsMean angles of the occipito-atlanto-axial extension in simple head extension and the sniffing position were 20.4°±5.1°and 24.2°± 5.6°, respectively (P < 0.01).ConclusionThe anatomic sniffing position provides greater occipito-atlanto-axial extension compared to simple head extension. These findings should be taken into consideration when optimizing patient positioning for laryngoscopy.RésuméObjectifLa position anatomique de reniflement est traditionnellement considérée comme la position standard de la tête et du cou pour la laryngoscopie; toutefois, des études récentes suggèrent que cette position ne présente aucun avantage significatif par rapport à la simple extension de la tête. Nous avons comparé l’angle d’extension occipito-atlaïdo-axial dans les positions de simple extension de la tête et de reniflement afin de déterminer si la position de reniflement présentait un avantage anatomique, l’angle étant un élément-clé dans l’obtention d’une bonne vision laryngée pendant la laryngoscopie.MéthodeL’étude portait sur trente volontaires avec colonnes cervicales normales. Chaque sujet a subi des examens radiologiques de la colonne cervicale latérale dans les trois positions suivantes: position neutre (à plat sur la table sans oreiller et sans extension ou flexion de la tête); extension simple de la tête (tête en extension maximale sans oreiller); et position de reniflement (extension de la tête avec flexion cervicale obtenue par une élévation occipitale de 7 cm). Les résultats ont ensuite été comparés.RésultatsLes angles moyens d’extension occipito-atlaïdo-axiale dans l’extension simple de la tête et la position de reniflement étaient de 20,4° ± 5,1° et 24,2° ± 5,6° respectivement (P < 0,01).ConclusionLa position anatomique de reniflement présente une plus grande extension occipito-atlaïdo-axiale que la simple extension de la tête. Ces résultats devraient être pris en compte pour obtenir un meilleur positionnement du patient lors de la laryngoscopie.

Severe subluxation in the sniffing position in a rheumatoid patient with anterior atlantoaxial subluxation.

SPECIAL attention should be paid to airway management in rheumatoid patients with atlantoaxial subluxation (AAS) because they may be at risk of life-threatening neurologic injury caused by worsening the subluxation in the head and neck position during airway maneuver. 1-5 Atlantoaxial subluxation is found in 11-46% of patients with rheumatoid arthritis and is classified into four groups according to the direction of the subluxation, including anterior AAS, posterior AAS, vertical AAS, and lateral AAS. 6,7 Anterior AAS is the most prevalent form, accounting for 80% of all types of subluxations. 6,7 In rheumatoid patients with anterior AAS, the degree of subluxation has been estimated in association with flexion and extension at the entire cervical spine (the head and neck) as a functional unit. 6,7 During flexion of the entire cervical spine, the atlas separates anteriorly from the axis, and the subluxation is worsened. On the contrary, during extension, the atlas slides backward until it rests against the dens of the axis, and the subluxation is reduced. Therefore, standard anesthesia textbooks advocate avoiding flexion of the head and neck in rheumatoid patients with anterior AAS. 3,4 The sniffing position is widely recommended as the standard head and neck position for conventional laryngoscopy. 8,9 This position consists of two components, which are severe extension of the head at the occipitoatlantoaxial (OAA) complex and slight flexion of the neck at the subaxial cervical segments. 8,9 In this position, the direction of movement of the OAA complex (head movement) and that of the subaxial segments (neck movement) are opposite. 8,9 Theoretically, extension of the OAA complex reduces the subluxation, and flexion of the subaxial segments makes it worse in rheumatoid patients with anterior AAS. In general, it is believed that accomplishment of the sniffing position is tolerated in these patients because the OAA complex where the subluxation occurs is extended, and the degree of the subaxial flexion is mild. 2,10 However, whether this position is safe is still unknown. We report a case of the rheumatoid patient with anterior AAS that was markedly worsened by the sniffing position.

Preoperative evaluation of extension capacity of the occipitoatlantoaxial complex in patients with rheumatoid arthritis: comparison between the Bellhouse test and a new method, hyomental distance ratio.

Background: The authors devised a new method, the hyomental distance ratio (HMDR), for preoperatively identifying patients with a reduced occipitoatlantoaxial extension capacity, which was defined as the ratio of the hyomental distance in head extension position to that in the neutral position. They compared the accuracy of the HMDR with that of the Bellhouse test in 40 patients with rheumatoid arthritis. Methods: Each patient wearing goggles on which a goniometer was mounted sat upright with the head in the neutral position and then extended the head maximally. The angle of the goggles and the hyomental distance were measured in the two head positions, and a lateral cervical radiograph was taken simultaneously. The Bellhouse angle was defined as a difference in the angles of the goggles between these positions. Results: Median values of the radiologic occipitoatlantoaxial extension angle and the Bellhouse angle were 11.2° and 24.9°, respectively. In 21 of 40 patients, the radiologic occipitoatlantoaxial extension angle was less than 12° (reduced occipitoatlantoaxial extension capacity). In these patients, extension of the median angle of 16.4° occurred at the subaxial regions and was greater than that of 8.5° in patients with a radiologic occipitoatlantoaxial extension angle of 12° or more (P < 0.01). As a result, a strong relation between the Bellhouse angle and radiologic occipitoatlantoaxial extension angle was not established (P < 0.01, r = 0.48). In contrast, the HMDR correlated well with the radiologic occipitoatlantoaxial extension angle (P < 0.0001, r = 0.88). The areas under the receiver operating characteristic curve of the Bellhouse test and the HMDR were 0.72 and 0.95, respectively. Conclusions: The HMDR was a good predictor of a reduced occipitoatlantoaxial extension capacity in patients with rheumatoid arthritis, but the Bellhouse test was not a clinically reliable method.

Efficacy of the Airway Scope on tracheal intubation in the lateral position: comparison with the Macintosh laryngoscope.

Background The Airway Scope (AWS) may become a rescue airway device to secure the airway in the lateral position. We evaluated the efficacy of the AWS on tracheal intubation in patients in this position in comparison with the Macintosh laryngoscope. Methods Seventy patients scheduled for surgery in the lateral position under general anaesthesia with tracheal intubation were randomised into two groups: intubation with the Macintosh laryngoscope and that with the AWS. After general anaesthesia and muscle relaxation, experienced anaesthetists performed laryngoscopy and intubation using either laryngoscope in the right or left lateral position. Laryngoscopic view, intubation time, intubation difficulty scale score and success rate of tracheal intubation (within 60 s) were recorded and compared between intubation with the Macintosh laryngoscope and that with the AWS. Results In the lateral position, the laryngoscopic view with the AWS was significantly better than that with the Macintosh laryngoscope (P < 0.01). Tracheal intubation was successful at the first attempt with the AWS in all patients and with the Macintosh laryngoscope in 85.3% of patients (P < 0.05). The median times to intubation with the AWS and with the Macintosh laryngoscope were 14 (interquartile range, 9–19) s and 29 (20–31) s, respectively (P < 0.01). Also, the AWS significantly reduced the intubation difficulty scale score compared with the Macintosh laryngoscope (P < 0.01). Conclusion In the situation in which securing the airway in the lateral position is required, the AWS is more effective than the Macintosh laryngoscope.

Anesthetic management of a patient with laryngeal amyloidosis

A 73-year-old woman who suffered from progressive hoarseness for 6 years and dysphagia without pain for 1 year presented with a soft tissue deposition on the posterior region of the vocal cords and narrowing in the subglottic area. Biopsy of this soft tissue and histological examination revealed laryngeal amyloidosis. A tracheostomy and partial removal of the amyloid were performed with general anesthesia. The airway was secured with a smaller diameter endotracheal tube, which was inserted atraumatically with Magills forceps. The larynx is a rare site for amyloidosis. Laryngeal amyloidosis is fragile and hemorrhagic. Therefore, massive bleeding may occur during intubation. Anesthetists should take care in intubating the tracheas of these patients and be aware of other systemic diseases in laryngeal amyloidosis.

A simple maneuver for confirmation of the guidewire during ultrasound-guided internal jugular vein cannulation

To the Editor, The use of ultrasound guidance for internal jugular vein cannulation increases the rate of success, reduces procedure time, and reduces the rate of complications. Although the utility of ultrasound has been well established, some problems remain even when ultrasound is used, such as accidental arterial puncture or penetration of the posterior wall of the internal jugular vein. To minimize mechanical injury, the use of a micropuncture technique with a fine needle and guidewire has been proposed. It is currently unknown whether the micropuncture technique reduces complications when compared with the larger needle and guidewire method typically used for internal jugular vein cannulation. Nevertheless, in theory, a fine needle and a thin guidewire may minimize mechanical injury and bleeding. The micropuncture technique may be particularly valuable in coagulopathic patients. In addition, a conscious patient has little discomfort with a small needle and guidewire. We have used a micropuncture Seldinger kit (CV Legaforce EX, Terumo, Tokyo, Japan) with a 21G needle, 0.015-inch guidewire, and 12G double-lumen catheter. Another problem with ultrasound-guided internal jugular vein cannulation is that the guidewire is not always visible on the ultrasound image. Before dilation, it is essential to confirm the guidewire within the venous lumen to avoid severe mechanical injury that may result from dilation. Nevertheless, a standard relatively large guidewire is sometimes invisible on the ultrasound image, and a thin guidewire can be even more difficult to visualize. To overcome this problem, we push the neck skin softly with the index finger just caudal to where the wire penetrates the skin after removal of the needle (Fig. 1) (Video, available as Electronic Supplementary Material). This maneuver facilitates confirmation of the guidewire within the venous lumen with the ultrasound image (Fig. 2A, B); (Video, available as Electronic Supplementary Material). With the skin pushed, the wire moves posteriorly away from the vein wall, which enhances the reflected ultrasound. In addition, the angle between the ultrasound beam and the wire becomes perpendicular.

Kounis syndrome during general anaesthesia and administration of adrenaline

During the course of anaphylaxis, occurrence of myocardial ischaemia has been known, which have recently been named as Kounis syndrome [1]. Regarding treatment for this syndrome, early intravenous administration of adrenaline is the key points for managing anaphylaxis [2–4] but adrenaline can aggravate myocardial ischaemia. Moreover, whether adrenaline is effective or not is controversial [5,6]. We report a case of Kounis syndrome during general anaesthesia in which administration of adrenaline was effective in both anaphylactic shock and myocardial ischaemia, and discuss perioperative problems about diagnosis and therapy. A 61-yr-old man was scheduled for varicose vein stripping. He had in good health, had no past history suggestive of allergy, and took no medications. The operation began uneventfully under spinal anaesthesia. Ten minutes after the start of surgery, the patient became confusional, severely hypotensive and tachycardic. Ephedrine, phenylephrine and noradrenaline were administered in addition to rapid infusion of normal saline but the patient remained hypotensive and tachycardic. Fifteen minutes after occurrence of hypotension, the ECG revealed ST segment elevation in a MCL5 lead. We suspected that hypotension was caused by left ventricular dysfunction as a result of myocardial ischaemia, and started nitroglycerin and noradrenaline continuously. But the patients condition remained unchanged. A few minutes later, the anaesthetist noticed a mildly or moderately erythematous rash at the patients face for the first time and

Malposition of the epiglottis associated with fiberoptic intubation.

A case in which the epiglottis was tucked into the laryngeal inlet by advancement of an endotracheal tube (ETT) during fiberoptic intubation, is presented. In this case, pulling the fibroscope, which was advanced under the displaced epiglottis, was effective for restoration.

Fluoroscopic observation of the occipitoatlantoaxial complex during intubation attempt in a rheumatoid patient with severe atlantoaxial subluxation.

ATLANTOAXIAL subluxation (AAS) is found in 11– 46% of patients with rheumatoid arthritis. Rheumatoid patients with AAS may be at risk of life-threatening neurologic injury caused by exacerbation of the subluxation in the head and neck position during airway maneuver; therefore, appropriate management of the cervical spine is essential. Tokunaga et al. have recommended the protrusion position, which is equal to the posture used in anesthesiology as the sniffing position, during intubation attempt in these patients to reduce subluxation. In contrast, previous studies have shown that accomplishment of the protrusion position sometimes results in worsening AAS in rheumatoid patients with severe instability of the occipitoatlantoaxial (OAA) complex. In cases of severe OAA instability, appropriate head and neck position during airway maneuver is poorly understood despite its importance. Minimizing movement of the cervical spine may be the only method for avoiding exacerbation of AAS and protecting the spinal cord. It is often difficult to predict the degree of cervical spine motion for laryngoscopy and intubation because the motion varies from individual to individual. Moreover, prediction is all the more difficult in patients with rheumatoid arthritis because their trachea is sometimes difficult to intubate. These indicate that, despite the necessity of minimizing cervical movement, the degree of the motion is not known until laryngoscopy and intubation are performed. Observation of the cervical motion during airway maneuver may provide a safer management. We report a case of fluoroscopic observation of the OAA complex during laryngoscopy and intubation in a rheumatoid patient with severe AAS. Case Report