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ABSTRACT: Although a life-threatening complication, pulmonary aspiration of gastric contents caused by vomiting or regurgitation during induction of anaesthesia cannot be prevented. It may be prevented if the mouth is placed more inferiorly than the larynx and tracheal bifurcation by the use of head-down tilt and head-neck positioning.
We aimed to determine the head-down tilt required to prevent aspiration in the neutral, simple extension, sniffing and full cervical spine extension (Sellick) positions and to investigate the relationship between pulmonary aspiration and the vertical height of the mouth, larynx and tracheal bifurcation.
Observational study.
Operating theatre at Nippon Steel Yawata Memorial Hospital.
Manikins with coloured fluid in the oesophagus and 30 adult volunteers.
Use of head-down tilt between 0° and 50° in 5° increments in four head-neck positions (neutral, simple extension, sniffing and Sellick).
Aspiration of oesophageal contents (coloured fluid) from the oesophagus into the trachea and bronchi. Measurement of the mouth-arytenoid angle (manikin and volunteers) and the mouth-carina angle (manikin).
The head-down tilts required to protect both the trachea and bronchi from aspiration were 45°, 35° and 10° in the neutral, simple extension and Sellick positions, respectively, which coincided with the mouth-arytenoid angle in those positions. The maximum tilt used in this study was not adequate to prevent aspiration in the sniffing position. The head-down tilt required to level the mouth with the tracheal bifurcation (mouth-carina angle) protected the bronchi from aspiration but not the trachea.
A head-down tilt equal to the mouth-arytenoid angle (levelling the mouth with the larynx) was necessary to completely prevent aspiration. This angle of tilt was within clinically relevant ranges only with the Sellick position.
European Journal of Anaesthesiology 05/2012; 29(8):380-5. · 2.23 Impact Factor
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International journal of cardiology 06/2011; 154(2):e34-5. · 7.08 Impact Factor
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ABSTRACT: 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.
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.
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).
In the situation in which securing the airway in the lateral position is required, the AWS is more effective than the Macintosh laryngoscope.
European Journal of Anaesthesiology 10/2010; 28(3):164-8. · 2.23 Impact Factor
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Canadian Anaesthetists? Society Journal 04/2010; 57(4):389-90. · 2.31 Impact Factor
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ABSTRACT: There are some disadvantages of the Airway Scope (AWS), and the most crucial one is that the AWS has only one fixed-size AWS blade. When the blade is too short to reach beneath the epiglottis and to lift it directly, an endotracheal tube hits the epiglottis and cannot be advanced into the glottic aperture even when it is visible. A bougie may solve this difficulty because its angulated tip can be controlled in a desired direction. Therefore, we examined the efficacy of the bougie on this problem.
Forty patients were randomly classified into two groups: intubation with only the AWS, and with the AWS and the bougie. After general anesthesia and muscle relaxation, the AWS blade tip was positioned in the vallecula, the glottis was fully exposed, and intubation using the AWS with or without a bougie was performed. Success rate and time to intubation were compared in both groups.
Success rate was 13/20 in intubation with only the AWS and 19/20 in intubation with the AWS and the bougie (P<0.05). Median intubation time was reduced from 48 sec without the bougie to 29 sec with the bougie (P<0.01).
Use of the bougie was useful for difficult intubation with the AWS caused by inability to lift the epiglottis directly.
Masui. The Japanese journal of anesthesiology 04/2010; 59(4):525-30.
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Anesthesiology 10/2009; 111(4):917-9. · 5.36 Impact Factor
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ABSTRACT: 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.
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.
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.
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.
Anesthesiology 06/2009; 110(6):1335-40. · 5.36 Impact Factor
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ABSTRACT: 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.
Journal of clinical anesthesia 03/2009; 21(1):61-3. · 1.32 Impact Factor
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ABSTRACT: The Airway Scope, one of the newest video-laryngoscopes, provides an excellent view of the larynx on a built-in monitor screen. Difficulty in introducing an endotracheal tube into the laryngeal aperture may occur, even though the aperture is visible. The bougie may solve this difficulty because its angulated tip can be controlled in a desired direction. The successful use of the bougie along with the Airway Scope in a full-stomach patient with a difficult airway is presented.
Journal of clinical anesthesia 03/2009; 21(1):64-6. · 1.32 Impact Factor
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Anesthesiology 03/2007; 106(2):403; author reply 403-4. · 5.36 Impact Factor
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ABSTRACT: While 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.
Thirty 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).
Mean angles of the occipito-atlanto-axial extension in simple head extension and the sniffing position were 20.4 degrees+/-5.1 degrees and 24.2 degrees+/-5.6 degrees, respectively (P<0.01).
The 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.
Canadian Journal of Anaesthesia 02/2007; 54(2):129-33. · 2.35 Impact Factor
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ABSTRACT: 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.
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.
Median values of the radiologic occipitoatlantoaxial extension angle and the Bellhouse angle were 11.2 degrees and 24.9 degrees , respectively. In 21 of 40 patients, the radiologic occipitoatlantoaxial extension angle was less than 12 degrees (reduced occipitoatlantoaxial extension capacity). In these patients, extension of the median angle of 16.4 degrees occurred at the subaxial regions and was greater than that of 8.5 degrees in patients with a radiologic occipitoatlantoaxial extension angle of 12 degrees 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.
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.
Anesthesiology 05/2006; 104(4):680-5. · 5.36 Impact Factor
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Anesthesiology 03/2006; 104(2):378-9; author reply 379-80. · 5.36 Impact Factor
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Anesthesiology 12/2004; 101(5):1235-7. · 5.36 Impact Factor
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ABSTRACT: Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome, described by McCarty et al., is a form of "seronegative rheumatoid arthritis" characterized by an acute-onset polyarthritis with pitting edema of the dorsum of both hands and/or both feet. The syndrome is prevalent in elderly men, completely remitted with a small dose of steroid over a relatively short period, and has a benign clinical course. We describe a case of RS3PE syndrome in a 61-year-old man undergoing a lobectomy of the lung and discuss anesthetic management for the syndrome.
Masui. The Japanese journal of anesthesiology 10/2004; 53(9):1039-41.
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Anesthesia & Analgesia 11/2003; 97(4):1205; author reply 1205-6. · 3.29 Impact Factor
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ABSTRACT: We examined the reliability of an airway evaluation test to assess the occipitoatlantoaxial (OAA) extension capacity described by Bellhouse et al. (Bellhouse test) in 20 adult volunteers with normal cervical spines. Each subject sat upright with the head in the neutral position and was then asked to extend the head maximally while attempting to move the neck as little as possible. The angle from the neutral position to the extreme extension was measured using the goggle-goniometer. Lateral cervical radiographs were taken in these positions, and the OAA extension angle was radiographically measured. Median values for OAA extension measured radiographically and extension of the head measured with the Bellhouse test were 21.5 degrees and 30 degrees, respectively. Extension of 9.5 degrees occurred at the subaxial regions, which could not be detected by inspecting surface contours of the neck. The extent of the subaxial extension was almost consistent with the degree of overestimation of the OAA extension capacity by the Bellhouse test. Because the subaxial extension occurred independent of the degree of the OAA extension, a strong relationship between the angle measured with the goggle-goniometer and the OAA extension angle measured radiographically was not established (P < 0.01, r(2) = 0.44). These findings mean that the test is not always accurate to evaluate the OAA extension capacity and will fail to detect a reduction of the OAA extension capacity if the subaxial regions are normal. Therefore, these problems derived from the Bellhouse test offer a potential for missing a prediction of difficult tracheal intubations because reduced OAA extension is one of the important factors that make intubation difficult. IMPLICATIONS: The Bellhouse test was not always accurate to evaluate the actual occipitoatlantoaxial extension capacity because of the inevitable occurrence of the subaxial extension. This may mean that some difficult endotracheal intubations will be unpredictable.
Anesthesia & Analgesia 11/2002; 95(5):1437-41, table of contents. · 3.29 Impact Factor
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ABSTRACT: With fibreoptic intubation, advancement of the endotracheal tube (ETT) through the glottis is blind. Thus, in patients with a laryngeal tumour, there is a potential for damage to the tumour. Previously, we proposed the use of a fibreoptic bronchoscope (FOB)-video camera system to permit visualization of tube passage. We used this technique successfully in a patient with a known difficult airway and a large glottic tumour.
A 61-yr-old man with a known history of difficult laryngoscopic intubation underwent laryngeal microsurgery for recurrence of a glottic tumour. As preoperative indirect laryngoscopy revealed a large, mobile, and pedunculated glottic lesion obstructing the glottic opening, we planned a conventional awake fibreoptic intubation. Endoscopy showed that the tumour partially obstructed the glottis and the space between the tumour and the glottic opening was very narrow. To avoid damage to the tumour, we changed to an alternative fibreoptic intubation technique. The FOB attached to a video camera was passed nasally and a jaw thrust manoeuver was applied, providing an excellent view of the larynx. An anesthesiologist inserted the ETT with a curved stylet orally, and carefully advanced the tube tip into the space between the tumour and the glottic opening under video control. Absence of damage to the tumour and passage of the tube between the cords were confirmed visually.
This alternative intubation technique, providing a view of the tube passage into the glottis, was a reasonable method to avoid potential damage to the glottic tumour by blind tube passage during conventional fibreoptic intubation.
Canadian Journal of Anaesthesia 03/2002; 49(2):203-6. · 2.35 Impact Factor
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Anesthesiology 04/2001; 94(5):935. · 5.36 Impact Factor
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ABSTRACT: PurposeTo assess the effect of cricoid pressure on the positioning of and ventilation through the laryngeal mask airway (LMA).
MethodsIn a double-blind, randomized design, the LMA was inserted with (CP[+] group, n = 20) or without double-handed cricoid pressure
(CP[−] group, n = 20). Ventilation through the LMA was assessed by measuring expiratory tidal volume and judged as adequate
when a mean expiratory tidal volume of ≥10 ml · kg−1 could be obtained. The LMA position was examined by fibreoscopy. The position of the mask relative to the cricoid cartilage
and the cervical spine was radiologically examined (n = 10 in each group).
ResultsVentilation was adequate in all patients in the CP[−] group but in only five patients (25%) of the CP[+] group (P < 0.001).
The glottis was visible fibreoptically below the mask aperture in all patients in the CP[−] group, but in only three patients
in the CP[+] group (P < 0.001). Fibreoscopy showed that the mask was not inserted far enough in the remaining 17 patients
of the CP[+] group. The reason for unsuccessful ventilation in the CP[+] group was excessive gas leakage (n = 2) and/or partial
or complete airway obstruction (n = 13), which was noted fibreoptically. The radiographs showed that the tip of the mask in
the CP[−] group was located below the level of the cricoid cartilage (C6 or C7 vertebra). The mask tip in the CP[+] group was above this level (C4 or C5 vertebra) (P < 0.01).
ConclusionCricoid pressure impedes positioning of and ventilation through the LMA.
ObjectifVérifier l’influence de la pression cricoïdienne sur la ventilation au masque laryngé (ML) et son positionnement.
MéthodesAu cours de cette étude aléatoire et en double aveugle, le LM a été inséré avec (groupe CP[+], n = 20) ou sans pression cricoïdienne
manuelle (groupe CP[−], n = 20). La ventilation par masque laryngée était évaluée par la mesure du volume courant expiré et
jugée suffisante lorsqu’on obtenait un volume minute expiré ≥10 ml · kg−1. La position du ML était vérifiée par fibroscopie. Chez dix patients de chaque groupe, l’examen radiologique a déterminé
la position du ML relativement au cartilage cricoïde et à la colonne cervicale.
RésultatsLa ventilation a été adéquate chez tous les patients du groupe CP[−] mais chez seulement cinq (25%) du groupe CP[+] (P < 0,001).
La glotte était visible par fibroscopie sous l’ouverture du masque chez tous les patients du groupe CP[−], mais chez seulement
trois du groupe CP[+]. La fibroscopie a montré que le masque n ’était pas inséré assez profondément chez les 17 autres patients
du groupe CP[+]. Cet échec ventilatoire dans le groupe CP[+] était causé par une fuite de gaz exagérée (n = 2) ou/et par l’obstruction
des voies aériennes partielle ou complète (n = 13), vérifiée par fibroscopie. Les radiographies ont révélé que la pointe du
masque dans le groupe CP[−] était située sous le niveau du cartilage cricoïde (C6 ou C7). Dans le groupe CP[+], la pointe du masque était située à un niveau plus élevé (C4 ou C5, P < 0,01).
ConclusionLa pression cricoïdienne nuit et à la ventilation au masque laryngé et a son positionnement.
Canadian Journal of Anaesthesia 04/1996; 43(10):1035-1040. · 2.35 Impact Factor
