prepackaged syringe, for instance blue in the Portexepidural set with both horizontal and vertical flanges(in contrast to vertical flanges only or a smoothplunger) can avoid confusion between syringes(Figure). The feel and weight of the loss of resistancesyringe with free and consistent movement of theplunger are well discernable to the experienced hand.One may preferably use such dedicated syringes forneuraxial drug administration. Further, once thesyringe is filled with the local anesthetic solution, itshould preferably be attached to the Luer lock con-nector on the epidural catheter rather than kept alongwith the other syringes containing drugs intended forparenteral administration. Alternatively, syringes con-taining local anesthetics may be kept along with theLuer lock adaptor in a sterile drape, beside the patient.

Such simple measures may hopefully, help avoidaccidental iv injections of local anesthetics.

Rajesh Mahajan MD

Jammu, India

RReeffeerreenncceess1 Favier JC, Da Conceiçao M, Fassassi M, Allanic L,

Steiner T, Pitti R. Successful resuscitation of seriousbupivacaine intoxication in a patient with pre-existingheart failure. Can J Anesth 2003; 50: 62–6.

2 Karaca S, Unlusoy EO. Accidental injection of intra-venous bupivacaine (Letter). Eur J Anaesthesiol 2002;19: 616–7.

3 Radhakrishna S. Syringe labels in anaesthetic inductionrooms. Anaesthesia 1999; 54: 963–8.

4 Thomas TA, Cooper GM. Maternal deaths from anesthe-sia. An extract from why mothers die 1997-1999. Theconfidential enquiries into maternal death in theUnited Kingdom. Br J Anaesth 2002; 89: 499–508.

5 Armitage EN. Lumbar and thoracic epidural block. In:Wildsmith JAW, Armitage EN, McClure JH (Eds.).Principles and Practice of Regional Anaesthesia, 3rd ed.New York: Churchill Livingstone; 2003: 139–68.

RE P LY :I agree with Dr. Mahajan that careful labelling ofsyringes is not sufficient. The use of pre-printed labelswith colour codes is an important measure to limit drugconfusion. For example, a grey colour code could be usedfor local anesthetics (Time Med labelling systems®, BurrRidge, IL, USA). A colour code is a visual alarm toavoid syringe swaps.

I also concur with the recommendation to use 10-mLdistinct syringes for neuraxial drug administration.However, the use of these 10-mL specific syringes is uncom-fortable for peripheral blocks when 20 to 40 mL volumesare injected. I propose the use of 30-mL Luer-lock syringesfor such blocks: 20 to 30 mL injection volumes are commonand 30-mL Luer lock syringes are not frequently used forother purposes (in France). Careful incremental injec-tions with repeated aspiration tests are primordial. In ourcase report,1 20-mL syringes where prepared for postopera-tive analgesia. The contents of one syringe were injected ivaccidentally. If a colour code or a 30-mL syringe had beenused, we may, hopefully, not have had to treat the dra-matic consequences of this iv injection of 20 mL of 0.375%bupivacaine + 15 µg clonidine.

Jean-Christophe Favier MD

Laurent Allanic MD

Metz Armées, France

RReeffeerreennccee1 Favier JC, Da Conceiçao M, Fassassi M, Allanic L,

Steiner T, Pitti R. Successful resuscitation of seriousbupivacaine intoxication in a patient with pre-existingheart failure. Can J Anesth 2003; 50: 62–6.

Choosing a laryngoscope blade: straightvs curved

To the Editor:Whilst we are impressed that Arino et al.1 recruitedand randomized 500 subjects for a study comparingdirect laryngoscopy using five different laryngoscopesby a single operator, we question their conclusion that

1078 CANADIAN JOURNAL OF ANESTHESIA

FIGURE Showing the plungers of various syringes. A) Loss ofresistance syringe (Portex); B) disposable plastic syringe; C) glasssyringe.

the Macintosh blade should be preferred to the Millerblade.

Instead, the study data suggest that in those pre-dicted to be a difficult intubation, the Miller bladewould offer the best chance of successfully intubatingthe trachea, although in those predicted to bestraightforward, the Macintosh would be the pre-ferred blade.

The vast majority of patients present no airway dif-ficulties and clearly, in these patients, we must allendeavour to avoid the complications associated withintubation. However, like Arino, we recognize thatintubating the trachea is the ultimate end-point fordetermining the efficacy of a laryngoscope blade. Inthose predicted to be difficult, this must be the over-riding consideration.

The data presented show that when a Miller bladewas used, no patient had a grade 3 or 4 laryngoscopicview, whereas eight out of 100 patients had a grade 3or 4 laryngoscopic view when using a Macintoshblade. In fact, one of the four patients who could notbe intubated was in the Macintosh group.

Finally, when applying any conclusions from thisstudy to our own practice, it is noteworthy that a veryhigh success rate for intubation was achieved for allfive blades. However, the over-riding factor in thechoice of any airway device should be the operator’spast experience and familiarity with the equipment.

Michael Lim MB BS FRCA

Charlotte Demspey MB BS FRCA

Michael Pead MB BS FRCA

London, UK

RReeffeerreennccee1 Arino JJ, Velasco JM, Gasco C, Lopez-Timoneda F.

Straight blades improve visualization of the larynxwhile curved blades increase ease of intubation: a com-parison of the Macintosh, Miller, McCoy, Belscope andLee-Fiberview blades. Can J Anesth 2003; 50: 501–6.

RE P LY :We consider that straight blades improve visualization ofthe larynx while curved blades increase ease of intuba-tion. A good laryngeal view with the intubating devicedid not equal ease of intubation. Since the most impor-tant aspect of any laryngoscopic intubation is the correctplacement of the endotracheal tube, and not the visual-ization of the larynx, we recommend the use of a curvedblade to improve the ease of intubation. Curved bladesprovide more room in the oropharynx to maneuver theendotracheal tube, even if the laryngeal view is Cormackgrade 3.1

When laryngoscopy is difficult with the curved blade(the epiglottis obstructs the view of the larynx) the use ofa straight blade may help to achieve adequate laryngealvisualization,2 but the ease of intubation may notimprove. Like Marks et al.3 we recognize that the curvedtip of the Miller blade offers better intubating conditionsthan other straight blades.

We agree that the operator´s experience and familiar-ity is an important factor in the choice of any airwaydevice.

Jose J. Arino MD PhD

Jose M. Velasco MD

Carmen Gasco MD PhD

Francisco Lopez-Timoneda MD PhD

Madrid, Spain

RReeffeerreenncceess1 Arino JJ, Velasco JM, Gasco C, Lopez-Timoneda F.

Straight blades improve visualization of the larynxwhile curved blades increase ease of intubation: a com-parison of the Macintosh, Miller, McCoy, Belscope andLee-Fiberview blades. Can J Anesth 2003; 50: 501–6.

2 Benumof JL. Difficult laryngoscopy: obtaining the bestview. Can J Anaesth 1994; 41: 361–5.

3 Marks RR, Hancock R, Charters P. An analysis oflaryngoscope blade shape and design: new criteria forlaryngoscope evaluation. Can J Anaesth 1993; 40:262–70.

To the Editor:I read with interest the recent article by Arino et al.,1

assessing the use of straight blades (Miller, Belscope)or curved blades (Macintosh, McCoy, Lee-Fiberview)in the improvement of visualization of the larynx andease of intubation.

It was noted in the conclusion that straight bladesgive the best visualization of the larynx. However,“the function of laryngoscopy is ease of placement ofthe endotracheal tube and a curved blade was optimalin this respect”.1

In the United Kingdom, in situations of difficultintubation a gum elastic bougie is traditionally used2

and has reported success rates of 96%.3 In this case visu-alization of the larynx to aid placement of the bougie isthe most important factor. The increased space in theoropharynx to maneuver the endotracheal tube (as pro-vided by a curved blade) is therefore not required, asstudies show that once the bougie has been placed thetube can always be railroaded into position.4 Hames etal. recently suggested greater success with fibrescopesbut at present in the UK these are not readily availableand require dual operators at a time of urgency.3

CORRESPONDENCE 1079