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Year : 2008  |  Volume : 52  |  Issue : 3  |  Page : 317-320 Table of Contents     

Paraglossal Straight Blade Intubation Technique-an Old Technique Revisited in Difficult Intubations: A Series of 5 Cases

Assistant Professor, Department of Anesthesia and ENT, Himalayan Institute of Medical Sciences, Jollygrant, Dehradun, Uttarakhand, India

Date of Acceptance02-Apr-2008
Date of Web Publication19-Mar-2010

Correspondence Address:
Sanjay Agrawal
Assistant Professor, Anaesthesia, Himalayan Institute of Medical Sciences, Jollygrant, Dehradun
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Source of Support: None, Conflict of Interest: None

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We as anaesthesiologist at times encounter patients with mandibular dystocias, and oral/oropharyngeal lesions for surgical management. Such patients pose a challenge for airway management and intubation and at times proce­dure may end with tracheostomy. The Macintosh curved blade laryngoscopy is gold standard for intubation. This technique may be technically flawed in conditions like vallecular cyst, tonsillar growth, mandibular dystocias and hemifacial microsmia. However the experience of otolaryngologists to visualize the glottis using a straight blade direct laryngoscope (Jackson type) in cases where anaesthesiologist fails, prompted us to use straight blade laryngoscope (Miller's) for intubation. Here we describe, review and discuss an alternative technique of paraglossal straight blade intubation. We have tried this technique in five patients of difficult intubation and were able to avoid emergency cricothyrotomy and tracheostomy.

Keywords: Paraglossal straight blade, Intubation, Vallecular cyst, Tonsillar growth, Mandibular dystocias and Hemifacial microsmia.

How to cite this article:
Agrawal S, Asthana V, Meher R, Singh D K. Paraglossal Straight Blade Intubation Technique-an Old Technique Revisited in Difficult Intubations: A Series of 5 Cases. Indian J Anaesth 2008;52:317-20

How to cite this URL:
Agrawal S, Asthana V, Meher R, Singh D K. Paraglossal Straight Blade Intubation Technique-an Old Technique Revisited in Difficult Intubations: A Series of 5 Cases. Indian J Anaesth [serial online] 2008 [cited 2021 May 8];52:317-20. Available from: https://www.ijaweb.org/text.asp?2008/52/3/317/60641

   Introduction Top

Patients with mandibular dystocias and oral/ oropharyngeal lesions posted for various surgeries, pose problem to an anaesthesiologist with regards to airway management. Causes for difficult intubation in these may be due to the lesions occupying the path of intubation, relative macroglossia as a consequence of skeletal ab­normalities [1],[2],[3],[4] reducing the space available for manipu­lation and insertion of endotracheal tube. The ability of paraglossal straight blade technique to give reliable view of larynx is confirmed by experience of E.N.T. sur­geons who rarely fail to visualize the vocal cords using straight blade. In anaesthetic practice, use of E.N.T. type straight blade has enabled good visualization of larynx where laryngoscopy with conventional blade has been unsuccessful [5] .Here we present the data of five cases of difficult intubations where alternative intuba­tion technique of paraglossal straight blade technique was tried and found to be successful for intubation. This technique is especially useful for management of diffi­cult airway at places lacking advance airway manage­ment gadgets.

   Case report Top

[Table 1] shows the profile of five patients taken up for various surgeries. All the patients were on preop­erative assessment declared as difficult intubations. Since fibreoptic bronchoscope was not available at the time, alternate airway management instruments such as LMA, cricothyroid puncture needle and standby sur­geons to perform emergency tracheostomy were at hand.

The patients were not premedicated in the ward. On shifting to the operating room (OR), glycopyrrolate 0.2 mg was given intravenously.

Inhalational induction of anaesthesia was done with incremental concentration of halothane in 66%nitrous oxide and oxygen .Care was taken that spontaneous ventilation was maintained at all time .When sufficient depth of anaesthesia was attained a small bolus of propofol(1mg.kg -1 )was given before attempting laryn­goscopy. Initially Macintosh laryngoscope was tried by an experienced anaesthesiologist of greater than 5 years of experience. As the attempts to visualize the larynx were unsuccessful, paraglossal straight blade technique was tried by the same anaesthesiologist using appro­priate sized Miller blade, introducing the blade from right hand side of the mouth. In all the cases Cormack and Lehanne intubation grade improved and intubation was successful.Cormack and Lehane grade as visual­ized during intubation by different blades were desig­nated as Mackintosh view(Mackintosh blade) and Paraglossal view(Miller blade, paraglossal approach). In two patients two attempts were needed for successful intubation.

   Description of paraglossal technique Top

In basic paraglossal technique [6] size 3 or 4 Miller's blade is passed from right corner of mouth, along the groove between tongue and tonsil using leftward and anterior pressure to displace the tongue to the left of laryngoscope and to maintain tongue in this position at all time. Blade is advanced; epiglottis visualized and tip of blade passed posterior to epiglottis. The blade is lifted anteriorly thus elevating the epiglottis directly and visualizing the glottic opening. If a good view is not achieved the blade should be kept lateral to the incisor and head rotated to left. In comparison to Macintosh technique this approach gives a better view of larynx at an expense of less space to manipulate the tracheal tube. As a consequence an assistant retracts the corner of the mouth and improve the maneuverability of the tube using a stylet.

   Discussion Top

Difficult intubation is defined, as a condition where conventionally trained anaesthesiologist is unable to in­tubate or ventilate the patient after 3 attempts. The pres­ence of difficult intubations is a common finding in pa­tients with oral/ pharyngeal lesions.

The cases with anticipated difficult intubations are usually managed along the awake limb of difficult air­way algorithm [7] . However unanticipated difficult intubations may be encountered usually after inducing anaesthesia. Various approaches have been evolved for dealing with these situations. Introduction of LMA by Archie J Brain [8] in 1981 has revolutionized unanticipated airway management, as this device is successful in main­taining the airway& ventilation even if intubation is not possible.

The use of Macintosh laryngoscope blade is a gold standard for intubation and is the preference of many of conventionally trained anaesthesiologists. The tech­nique is usually atraumatic, gives a good view of glottis and its ease of use has made it a preferred technique. The high success rate leads to complacency regarding the role of alterative laryngoscopy and techniques; with consequent failure to develop skill in their use [9],[10],[11] .

The use of fibreoptic intubations has changed the scenario in cases of difficult intubation [12],[13] . However its use is precluded by high cost and expertise required for its use. Its use in emergency condition is hampered due to presence of blood/mucus/secretions. Use of fi­bre optic bronchoscope through LMA, ILMA for in­tubation has greatly increased the efficacy of this pro­cedure for successful intubation. Due to the above cited problems, an alterative technique of intubation using more than one type of laryngoscope& blades have been recommended by many authorities for increasing the chances of success. Hex Venn [14] described the suc­cessful use of rigid bronchoscope inserted from right side of mouth in a grade 4 (Cormack& Lehanne clas­sification) laryngoscopy patients when other techniques have failed to achieve tracheal intubation and specu­lated that use of straight laryngoscope blade from side of mouth could improve glottic visualization in such patient.

The advantage of visualsation using Miller's blade is better view but at an expense of limited space of manipulation of tracheal tubes. As a consequence use of stylet/bougie with retraction of corner of the mouth by assistant improves maneuverability of tracheal tube.

The causes of difficult intubation are multifold, rang­ing from inadequate mouth opening, limited extension of head over neck, TM joint pathology, retrognathia, micrognathia, relative macroglossia, anterior larynx or posterior displacement of epiglottis obscuring the glot­tic view. Other problems of intubation associated with large oral and oropharyngeal lesions are:

  1. Direct laryngoscopy usually fails to expose epi-­lottis as lesions are large, fragile and tend to bleed.
  2. Some swelling can impinge against epiglottis, dis­placing it posteriorly. This makes mobilization of epiglottis difficult with usual laryngoscopy [16].
  3. Use of neuromuscular block for intubation leads to pharyngeal muscles relaxation causing further posterior movement of tongue and epiglottis [17].
  4. Multiple direct laryngoscopic attempts can cause edema and/or bleeding with subsequent difficult ventilation.
Disadvantage of Macintosh blade in such cases may be due to the following causes:­

  1. The contribution of soft tissue of oral cavity may play an important role in difficult intubation. Rela­tive macroglossia usually as a consequence of skel­etal abnormalities may be a major problem in most cases of difficult intubation [18].
  2. In cases where the volume of oral/pharyngeal cavity is less and size of tongue are relative large leads to difficult airway thus leaving the anaesthesiologist to deal with secondary effects of soft tissue.
  3. Insuch cases use of Macintosh blade not only dis­places the tongue to left but also compresses the residual volume distally to 'pear drop' shape so that epiglottis is displaced posterior towards pha­ryngeal wall and thus obstructing the glottic view. Thus this technique may be fundamentally flawed in presence of absolute or relative macroglossia [18] .
The cause of improved view by paraglossal straight blade technique is due to contribution from both the paraglossal approach and the straight blade laryn­goscope. The actual mechanism for improved visual­ization is due to reduction of soft tissue compression (central component of line of sight) and lowering of proximal end of line of sight [19],[20] . Moreover the straight blade overcomes the problem of intrusion of curvature of Macintosh blade into the line of sight. Improved view by extension of head is possible with use of straight blade but not with curved blade.

The ability of paraglossal straight blade technique to give reliable view of larynx is confirmed by experi­ence of E.N.T. surgeons who rarely fail to visualize the vocal cords using straight blade. Normally the direct laryngoscope (Jackson type) is held close to center of mouth. They normally move tongue to left of laryngo­scope. In anaesthetic practice use of E.N.T. type straight blade has enabled good visualization of larynx where laryngoscopy with conventional blade has been unsuc­cessful.

Thus in conclusion this technique leads to successful intubations in cases where Macintosh blade fails. The result in literature is encouraging and raises a ques­tion as to why this technique is not practiced regularly? This technique warrants practice for its use with confi­dence when laryngoscopy proves difficult with other techniques.

   References Top

1.Bellhouse CP, Dore C. Criteria for estimating likelihood of difficulty of endotracheal intubation with Macintosh laryngoscope. Anesthesia and Intensive Care 1988; 16: 329-37.  Back to cited text no. 1      
2.Charter P. Analysis of mathematical model for osseous factors in difficult intubation. Canadian Journal of Anes­thesia 1994;41:5940-602.  Back to cited text no. 2      
3.Cormack R S, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39:1105-11.  Back to cited text no. 3      
4.Mallampati SR, Gatt SP, Gugino LD, et al. A clinical sign to predict difficult tracheal intubation- a prospective study. Canadian Journal of Anesthesia 1985; 32:429-34.  Back to cited text no. 4      
5.Crinquette V, Vilette B, Solanet C, et al. Appraisal of PCV, a laryngoscope for difficult endotracheal intubation. Annales Francaises D 'Anesthesie Ct dc Re'animation 1991; 10:589-94.  Back to cited text no. 5      
6.Henderson JJ. The use of paraglossal straight blade laryn­goscopy in difficult tracheal intubation. Anaesthesia. 1997;52:552-60.  Back to cited text no. 6      
7.Benumof JL. Laryngeal mask airway and the ASA diffi­cult airway algorithm. Anesthesiology 1996; 84: 686-99.  Back to cited text no. 7      
8.Brain AJ. The laryngeal mask airway-a new concept in airway management. Br J Anaesth 1983; 55:801-7.  Back to cited text no. 8      
9.Macintosh RR. A new laryngoscope. Lancet 1943; 1:205.  Back to cited text no. 9      
10.Macintosh RR. Laryngoscope blade. Lancet 1944; 1:485.  Back to cited text no. 10      
11.Horton WA, Fahy I, Charters P. Position of Macintosh blade during laryngoscopy. Br J Anaesth1988; 61:109.  Back to cited text no. 11      
12.Fulling PD, Roberts JT. Fibreoptic Intubation. Interna­tional Anaesthesiology Clinics 2000 38:189-217.  Back to cited text no. 12      
13.Fiberoptic Airway Management In: Anesthesiology clin­ics of North America. The upper airway and anesthesia 2002; 20:933-52.  Back to cited text no. 13      
14.Hex Venn P. The gum elastic bougie. Anaesthesia 1993; 48:274-5.  Back to cited text no. 14      
15.Golding-Wood DG, Whittet HB. The lingual tonsil. A ne­glected symptomatic structure? J Laryngol Otol 1989; 103: 922-5.  Back to cited text no. 15      
16.Sato N, Nakazawa T, Nakasuji I, Shingu K. Fiberoptic tracheal intubation aided by jaw lifting in a patient with an epiglottic cyst. Masui 2002; 51:910-2.  Back to cited text no. 16      
17.Jones DH, Cohle SD. Unanticipated difficult airway sec­ondary to lingual tonsillar hyperplasia. Anesth Analg 1993; 77: 1285-8.  Back to cited text no. 17      
18.Horton WA, Fahy L, Carters P. Factor analysis in difficult tracheal intubation: Laryngoscopy induced airway ob­struction. British journal of Anaesthesia 1990; 65:801-5.  Back to cited text no. 18      
19.Handler SD, Keon TP. Difficult laryngoscopy/intubation the child with mandibular hypoplasia. Annals of Otology Rhinology Laryngology 1983;92:401-4.  Back to cited text no. 19      
20.Diaz ZH, Guarisco JL, LeJeune FE Jr. A modified tubular pharyngolaryngoscope for difficult pediatric laryngos­copy. Anesthesiology 1990; 73:357-8.  Back to cited text no. 20      


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