144
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epidural catheter and weighing the benefits to the patient, this poses a small risk. We suggest that an intravascular epidural catheter with a clot can still be salvaged when the primary insertion of the needle or catheter was difficult.
i)
Shaul Cohen MD David Amar MD Department of Anesthesiology Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx, NY 10461 REFERENCES 1 Youngstrom P, Sedensky M, Frankmann D, Spagnuolo S. Continuous epidural infusion of low-dose bupivacainefentanyi for labor analgesia. Anesthesiology 1988; 69: A686. 2 Bromage PR. Physiology and pharmacology of epidural analgesia. Anesthesiology 1967; 28: 592-662. 3 Bromage PR. Epidural Analgesia. Philadelphia: W.B. Saunders, 1978; 560. 4 VerniquetAJW. Vessel puncture with epidural catheters. Experience in obstetric patients. Anaesthesia 1980; 35: 660-2. 5 McNeill MJ. Cannulation of the epidural space. A comparison of 18- and 16-gauge needles. Anaesthesia 1988; 43: 154-5. 6 RyanOW. Accidentalintravenousinjectionofbupivacaine: a complication of obstetrical epidural anaesthesia. Br J Anaesth 1973; 45: 907-8. 7 Raitt DG. Delayed blockage in an extradural catheter. Br J Anaesth 1980; 52: 242. 8 Patteson SK, Smith AA, Langdon JR. Management of an intravascular epidural catheter. Anesthesiology 1988; 69: 153-4. 9 Freeman AB. Epidural fentanyl as a test dose. Anesth Analg 1989; 68: 187-8.
A simple method to facilitate difficult intubation To the Editor: Difficult intubation remains one of the anaesthetist's nightmares. It has been estimated that 90 per cent of cases of difficult intubation should be anticipated but ten per cent will occur unexpectedly in clinical practice.~ Such cases may present to anaesthetists of all levels of experience and plans to cope with them should be taught to the trainee at an early stage. Many of the techniques involve invasive manoeuvres which may not be practised
__./------
(b)
/
,' /
FIGURE 1 Diagrammaticrepresentationof the distal (a) and midpoint bends (b) of the tracheal tube.
during routine cases. We describe here a simple adaptation of a conventional tracheal tube ('IT) which we have found useful during difficult intubation. A silicone coated malleable introducer is well lubricated and inserted into a disposable TT so that its tip just protrudes from the distal end of the tube. The distal 5 cm of the TT is then bent anteriorly to an angle of 70-90 ~ (Figure la). A more acute bend may prevent subsequent withdrawal of the introducer. The midpoint of the TT is then bent to the left or right at an angle of 70-80 ~ to the first bend (Figure lb). The final shape is shown in Figure 2. The advantages of the newly configured tube are evident. The distal bend gives better access tO an anteriorly placed larynx whereas the bend in the middle of the tube enables a clear view of the larynx to be maintained during the whole intubation sequence as the proximal part of the tube does not obscure the laryngeal opening or the epiglottis/arytenoids. Inaddition, rotation of the proximal end of the tube allows the distal tip to be moved anteriorly or posteriorly with a minimum of effort whilst still maintaining a good view of the epiglottis or larynx. Even in Cormack grades III and IV difficult intubations 2 the end of the modified "IT can be inserted behind the epiglottis or its expected position. Gentle manipulation of the proximal end of the tube will then guide the tip towards the laryngeal opening and through the cords. When the larynx has been successfully intubated the introducer is withdrawn and the tube returns to its former shape. Many techniques have been described to facilitate
CORRESPONDENCE
145
A device for small-bore spinal needles for immediate detection of CSF
FIGURE2 The modifiedtracheal tube. difficult tracheal intubation. Simple manoeuvres such as changes in position of the neck, application of cricoid pressure or the use of a smaller tube or introducer may be useful. Blind nasal intubation or "railroading" a T r over a bougie are other options but these manoeuvres may aggravate an already difficult situation by causing bleeding. Cricothyroid puncture and the retrograde passage of a soft tipped wire 3 through the larynx is an alternative method of "railroading" the TI" but this invasive technique cannot be practised in normal patients. More recently the fibreoptic intubating bronchoscope 4 has gained favour for the difficult case b~t practice is required to master this technique. The expertise required for a difficult intubation is called for infrequently. We describe a non-invasive technique using equipment which is available in every anaesthetic room and which may be practised in normal patients thus improving the success rate in the occasional patient who is difficult to intubate. Martin Smith Maas FFARCS Robert J. Buist MBBS FFARCS N.Y. Mansour MBBSFFARCS Medway Hospital, Gillingham Kent, U.K. REFERENCES
1 Sia RL, Edens ET. How to avoid problems when using
the fibreoptic bronchoscope for difficult intubations. Anaesthesia .1981 ; 36: 74-5. 2 Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39:1105-11. 3 Roberts KW. New use for a Swan-Ganz introducer wire. Anes~ Anatg 1981; 60: 67. 4 Taylor PA, Towey RM. The broncho-fibrescope as an aid to endotracheal intubation. Br J Anaesth Anaesth 1972; 44:611-2.
To the Editor: Gerrish and Peacock t showed that a prolonged time (up to 66 see) may elapse before a fluid meniscus is seen when small diameter spinal needles are used. The in vitro flow of the 26-gauge needle with an internal diameter of 0.272 mm (Steriseal) and CSF pressure of 12 cm was found to be 0.084 ml.sec -~. For comparison, flow through the 22-gauge spinal needle (Steriseal) was seven times faster (0.588 ml. sec-t). To accelerate the appearance of CSF through the small-bore spinal needle we used a device comprised of a small part of an extension tube cut at its male end. This is attached to the spinal needle and filled with an anaesthetic solution (Figure).
FIGURE A cut male end of an extension tube connected to a 25G spinal needle. The same device was used by Mustafa and Milliken 2 to identify the epidural space. When the dura is punctured the fluid in the extension tube is immediately pushed out by the CSF fluid pressure. It requires only a very small amount of CSF to push the fluid level and to confirm the presence of the spinal needle in the spinal space. Slattery et al.3 recommended gentle aspiration through a 25-gauge. spinal needle to facilitate the time of CSF appearance. Also a clear hub needle allows a shorter appearance time. The device described may aid in performing spinal anaesthesia through the small-bore spinal needle and avoid multiple unnecessary attempts at dural puncture. Joseph Eldor MD Department of Anesthesia Hadassah Medical Centre, Ein Karem P.O. Box 12000 Jerusalem 91120 Israel
C A N A D I A N J O U R N A L OF A N A E S T H E S I A
epidural catheter and weighing the benefits to the patient, this poses a small risk. We suggest that an intravascular epidural catheter with a clot can still be salvaged when the primary insertion of the needle or catheter was difficult.
i)
Shaul Cohen MD David Amar MD Department of Anesthesiology Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx, NY 10461 REFERENCES 1 Youngstrom P, Sedensky M, Frankmann D, Spagnuolo S. Continuous epidural infusion of low-dose bupivacainefentanyi for labor analgesia. Anesthesiology 1988; 69: A686. 2 Bromage PR. Physiology and pharmacology of epidural analgesia. Anesthesiology 1967; 28: 592-662. 3 Bromage PR. Epidural Analgesia. Philadelphia: W.B. Saunders, 1978; 560. 4 VerniquetAJW. Vessel puncture with epidural catheters. Experience in obstetric patients. Anaesthesia 1980; 35: 660-2. 5 McNeill MJ. Cannulation of the epidural space. A comparison of 18- and 16-gauge needles. Anaesthesia 1988; 43: 154-5. 6 RyanOW. Accidentalintravenousinjectionofbupivacaine: a complication of obstetrical epidural anaesthesia. Br J Anaesth 1973; 45: 907-8. 7 Raitt DG. Delayed blockage in an extradural catheter. Br J Anaesth 1980; 52: 242. 8 Patteson SK, Smith AA, Langdon JR. Management of an intravascular epidural catheter. Anesthesiology 1988; 69: 153-4. 9 Freeman AB. Epidural fentanyl as a test dose. Anesth Analg 1989; 68: 187-8.
A simple method to facilitate difficult intubation To the Editor: Difficult intubation remains one of the anaesthetist's nightmares. It has been estimated that 90 per cent of cases of difficult intubation should be anticipated but ten per cent will occur unexpectedly in clinical practice.~ Such cases may present to anaesthetists of all levels of experience and plans to cope with them should be taught to the trainee at an early stage. Many of the techniques involve invasive manoeuvres which may not be practised
__./------
(b)
/
,' /
FIGURE 1 Diagrammaticrepresentationof the distal (a) and midpoint bends (b) of the tracheal tube.
during routine cases. We describe here a simple adaptation of a conventional tracheal tube ('IT) which we have found useful during difficult intubation. A silicone coated malleable introducer is well lubricated and inserted into a disposable TT so that its tip just protrudes from the distal end of the tube. The distal 5 cm of the TT is then bent anteriorly to an angle of 70-90 ~ (Figure la). A more acute bend may prevent subsequent withdrawal of the introducer. The midpoint of the TT is then bent to the left or right at an angle of 70-80 ~ to the first bend (Figure lb). The final shape is shown in Figure 2. The advantages of the newly configured tube are evident. The distal bend gives better access tO an anteriorly placed larynx whereas the bend in the middle of the tube enables a clear view of the larynx to be maintained during the whole intubation sequence as the proximal part of the tube does not obscure the laryngeal opening or the epiglottis/arytenoids. Inaddition, rotation of the proximal end of the tube allows the distal tip to be moved anteriorly or posteriorly with a minimum of effort whilst still maintaining a good view of the epiglottis or larynx. Even in Cormack grades III and IV difficult intubations 2 the end of the modified "IT can be inserted behind the epiglottis or its expected position. Gentle manipulation of the proximal end of the tube will then guide the tip towards the laryngeal opening and through the cords. When the larynx has been successfully intubated the introducer is withdrawn and the tube returns to its former shape. Many techniques have been described to facilitate
CORRESPONDENCE
145
A device for small-bore spinal needles for immediate detection of CSF
FIGURE2 The modifiedtracheal tube. difficult tracheal intubation. Simple manoeuvres such as changes in position of the neck, application of cricoid pressure or the use of a smaller tube or introducer may be useful. Blind nasal intubation or "railroading" a T r over a bougie are other options but these manoeuvres may aggravate an already difficult situation by causing bleeding. Cricothyroid puncture and the retrograde passage of a soft tipped wire 3 through the larynx is an alternative method of "railroading" the TI" but this invasive technique cannot be practised in normal patients. More recently the fibreoptic intubating bronchoscope 4 has gained favour for the difficult case b~t practice is required to master this technique. The expertise required for a difficult intubation is called for infrequently. We describe a non-invasive technique using equipment which is available in every anaesthetic room and which may be practised in normal patients thus improving the success rate in the occasional patient who is difficult to intubate. Martin Smith Maas FFARCS Robert J. Buist MBBS FFARCS N.Y. Mansour MBBSFFARCS Medway Hospital, Gillingham Kent, U.K. REFERENCES
1 Sia RL, Edens ET. How to avoid problems when using
the fibreoptic bronchoscope for difficult intubations. Anaesthesia .1981 ; 36: 74-5. 2 Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39:1105-11. 3 Roberts KW. New use for a Swan-Ganz introducer wire. Anes~ Anatg 1981; 60: 67. 4 Taylor PA, Towey RM. The broncho-fibrescope as an aid to endotracheal intubation. Br J Anaesth Anaesth 1972; 44:611-2.
To the Editor: Gerrish and Peacock t showed that a prolonged time (up to 66 see) may elapse before a fluid meniscus is seen when small diameter spinal needles are used. The in vitro flow of the 26-gauge needle with an internal diameter of 0.272 mm (Steriseal) and CSF pressure of 12 cm was found to be 0.084 ml.sec -~. For comparison, flow through the 22-gauge spinal needle (Steriseal) was seven times faster (0.588 ml. sec-t). To accelerate the appearance of CSF through the small-bore spinal needle we used a device comprised of a small part of an extension tube cut at its male end. This is attached to the spinal needle and filled with an anaesthetic solution (Figure).
FIGURE A cut male end of an extension tube connected to a 25G spinal needle. The same device was used by Mustafa and Milliken 2 to identify the epidural space. When the dura is punctured the fluid in the extension tube is immediately pushed out by the CSF fluid pressure. It requires only a very small amount of CSF to push the fluid level and to confirm the presence of the spinal needle in the spinal space. Slattery et al.3 recommended gentle aspiration through a 25-gauge. spinal needle to facilitate the time of CSF appearance. Also a clear hub needle allows a shorter appearance time. The device described may aid in performing spinal anaesthesia through the small-bore spinal needle and avoid multiple unnecessary attempts at dural puncture. Joseph Eldor MD Department of Anesthesia Hadassah Medical Centre, Ein Karem P.O. Box 12000 Jerusalem 91120 Israel
