A modified nasal trumpet to facilitate fibreoptic intubation

S. Metz*,1 and C. Beattie2

1 Anesthesia Service, MCP Hospital, 3300 Henry Avenue, Philadelphia, PA 19129-1191, USA. 2 Department of Anesthesiology, New York University School of Medicine, 400 East 34th Street, Room 626, New York, NY 10016, USA

Corresponding author. E-mail: samuel.metz@drexel.edu
{dagger}LMA® is the property of Intavent Limited.

Accepted for publication: September 14, 2002


    Abstract
 Top
 Abstract
 Introduction
 Methods
 Discussion
 References
 
Background. The modified nasal trumpet (MNT) is a standard nasopharyngeal airway with an added distal fenestration and fitted with a 15 mm adaptor to permit connection to an anaesthesia circuit.

Methods. Based on its successful use as an emergency device in the ‘cannot intubate, cannot ventilate’ scenario, we considered that the MNT would aid fibreoptic intubation by providing a patent airway, spontaneous ventilation, and inhalation anaesthesia during the procedure. We report use of the MNT for this purpose seven times in six patients with difficult airways.

Results. In each case, the MNT allowed oxygenation and general anaesthesia while maintaining spontaneous ventilation when awake intubation was unsuccessful or not possible.

Conclusion. The MNT has a place in the operating room suites as a useful airway management device.

Br J Anaesth 2003; 90: 388–91

Keywords: equipment, airway; airway, complications


    Introduction
 Top
 Abstract
 Introduction
 Methods
 Discussion
 References
 
In 1969, the binasal pharyngeal airway was reported as an alternative to tracheal intubation.1 2 This was two nasopharyngeal airways joined to a single adaptor and connected to an anaesthesia circuit. Despite its success for elective and emergency airway management, it disappeared from clinical use. One of us (C.B.) has successfully used an adaptation of this device, the modified nasal trumpet (MNT), as an airway rescue device to facilitate positive pressure ventilation in emergencies.3 This MNT consists of a nasopharyngeal airway modified with the addition of a 15 mm adaptor from an endotracheal tube (ETT) and a cut distal fenestration (Fig. 1). The adaptor allows connection to an anaesthesia circuit or self-inflating bag. The added fenestration permits gas flow if the distal opening is occluded.



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Fig 1 Modified nasal trumpet.

 
Inspired by success in the ‘cannot intubate, cannot ventilate’ scenario,3 we considered that the MNT would allow spontaneous ventilation for inhalation anaesthesia during fibreoptic intubations when awake intubation was not possible. We report seven cases using the device in six patients, intubated successfully with the aid of the MNT despite challenging circumstances.


    Methods
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 Abstract
 Introduction
 Methods
 Discussion
 References
 
MNTs were constructed using pre-packaged nasopharyngeal airways (Kendall Argyle, Mansfield, MA, USA). One or two distal fenestrations were added by cutting a hole near the distal end. These nasal airways were then mated to ETT adaptors. A nasopharyngeal airway between 7.5 and 8.5 mm (30–34 French) will accept an adaptor from a 7.0 to 8.0 mm ETT. We usually combine an 8.5 mm nasopharyngeal airway with an 8.0 mm adaptor.

All patients were pre-treated with oxymetazoline 0.05% spray to reduce risk of haemorrhage. All devices were lubricated with either surgical lubricant or lidocaine 2% gel. Patients were positioned with their backs at least 45 degrees from the horizontal. To reduce trauma to turbinates, we usually first attempted passage via the left nostril, placing the leading edge on the medial side of the nasal chamber away from the turbinates and with the preformed curve of the airway directed caudad. After insertion the MNT was connected to the anaesthesia circuit.

Case reports
Patient 1
A 76-yr-old female (height 157 cm, weight 123 kg) had refused an elective operation to resect a periglottic tumour 1 week before. She then presented in the emergency department with respiratory distress and inability to swallow. Nasal pharyngoscopy showed a large supraglottic tumour obscuring the airway, with bubbling froth in the posterior pharynx. The surgeons considered the tumour a relative contraindication to tracheostomy.

On arrival in the operating room, the patient was gasping with saliva bubbling from her mouth. She was tachypnoeic with a ventilatory frequency of 30 bpm, exhausted, but cooperative. Voluntary mouth opening was limited. Mallampati classification was 4. The cricothyroid membrane was obscured by fat. Pulse oximeter saturation with supplemental oxygen by nasal cannula was 90%. We planned an awake nasal fibreoptic intubation.

The patient was given i.v. glycopyrrolate. Both nostrils were prepared with lidocaine 2% gel. An MNT was inserted into the right nostril and connected to the anaesthesia circuit. Saturation increased to 100%. Several attempts to pass a fibrescope through the vocal cords via the left nostril failed because of copious secretions and the rapid breathing of the patient moving all landmarks.

Sevoflurane was added to the fresh oxygen flow. After the patient lost consciousness, the jaw was lifted and the mouth closed to permit assisted ventilation with the reservoir bag. The deeper assisted breaths brought the patient’s spontaneous rate down to 10 bpm and positive pressure enlarged the pharyngeal diameter. Saturation remained 100%. With the pharynx distended and a slower ventilatory frequency, the trachea was easily entered with the fibrescope and the ETT passed into the trachea.

Patient 2
This patient was a 55-yr-old female undergoing elective mastectomy. After induction of general anaesthesia with thiopental and succinylcholine, three attempts to see the glottis by direct laryngoscopy were unsuccessful. Blind placement of an ETT with a stylet also failed. Mask ventilation was easy throughout. The patient resumed spontaneous ventilation and was permitted to recover. With the patient awake but drowsy, topical anaesthesia of the mouth and pharynx was applied in preparation for an awake oral fibreoptic intubation, secretions made the topical anaesthetic ineffective. The patient’s nostrils were then prepared with lidocaine 2% gel, which allowed insertion of a MNT in the left nostril. After breathing sevoflurane in oxygen until unresponsive, the patient then tolerated an oral fibreoptic intubation while breathing spontaneously.

Patient 3
A 43-yr-old male (height 188 cm, weight 168 kg) for a femoral-popliteal bypass graft, refused awake intubation and regional anaesthesia. An anaesthesia record from the week before stated an uneventful rapid sequence intubation with direct laryngoscopy. A similar approach was planned for this anaesthetic.

After preoxygenation and induction of anaesthesia with thiopental and succinylcholine, direct laryngoscopy showed no recognizable landmarks beyond the tongue. Lighted stylet intubation failed. Bag and mask ventilation required extreme jaw lift but maintained arterial saturation greater than 90%. The patient was allowed to resume spontaneous ventilation, and a left-sided MNT inserted. The patient then breathed sevoflurane in oxygen spontaneously with assisted breathing and manual mouth closure. Nasal fibreoptic intubation through the right nostril was successful.

Later, it was found that the previous intubation had been difficult, with the use of a gum elastic bougie.

Patient 4
This patient was a 20-yr-old male for elective reduction of a mandibular fracture, in whom mouth opening was limited by pain. A nasal ETT was needed and the patient refused an awake intubation. After preoxygenation by mask, anaesthesia was induced with i.v. thiopental, maintaining spontaneous ventilation. Both nostrils were lubricated with lidocaine gel 2%. A MNT was inserted into the right nostril and connected to the anaesthesia circuit. General anaesthesia was maintained with sevoflurane in oxygen. An adult fibrescope armed with a nasal RAE ETT was passed through the left nostril into the pharynx. Additional topical anaesthesia was provided by lidocaine 1% sprayed through the working channel of the fibrescope. The fibrescope and then the ETT were passed without difficulty into the trachea. The patient breathed spontaneously during the intubation.

Two days later, the patient returned to the operating room for further fixation of the fracture. The trachea was intubated in a similar fashion with spontaneous ventilation of sevoflurane in oxygen through a MNT during nasal fibreoptic intubation through the other nostril.

Patient 5
A mentally handicapped 29-yr-old female to have oral dental clearance would not cooperate with insertion of an i.v. catheter, so she received i.m. ketamine in the holding area. After arrival in the operating room, oxygen was administered by mask while an i.v. catheter was inserted. The patient was given glycopyrrolate i.v. and lidocaine 2% gel to both nostrils. A right-sided MNT was connected to the anaesthesia circuit. With the patient spontaneously breathing sevoflurane in oxygen, nasal fibreoptic intubation was done via the left nostril without difficulty.

Patient 6
A 31-yr-old male had undergone repair of a zygomatic-maxillary complex fracture 3 weeks before. He presented with facial cellulitis and swelling over the operative area, and required urgent incision and drainage.

Examination showed painful swelling over the left cheek preventing voluntary mouth opening and limiting neck extension. Breathing through the mouth was limited. Placing a mask over the face was painful. Nasal fibreoptic intubation during anaesthesia with spontaneous breathing was planned.

Anaesthesia was induced with thiopental, preserving spontaneous ventilation. A right-sided MNT was placed and connected to the anaesthesia circuit. Anaesthesia was maintained with sevoflurane in oxygen. Fibreoptic intubation through the left nostril was uneventful. The MNT was kept in place until after extubation and full recovery of consciousness.


    Discussion
 Top
 Abstract
 Introduction
 Methods
 Discussion
 References
 
Nasopharyngeal airways have been used for over 100 yr.4 Their use for primary airway management has declined and is rarely mentioned in the anaesthesia literature. We tested whether a standard nasopharyngeal airway could be used safely and effectively to facilitate elective and semi-elective fibreoptic intubation in spontaneously breathing patients. Our experience confirmed the value of the MNT in these circumstances.

The MNT is functionally similar to both the laryngeal mask airway (LMA{dagger})5 and the cuffed oropharyngeal airway (COPA).6 The MNT establishes a patent airway (may substitute for mask ventilation in the unintubated patient), permits positive pressure ventilation, and can be placed blindly.

As a tool to facilitate intubation, it is potentially superior to both the LMA and the COPA. The MNT may be inserted in a spontaneously breathing patient, either awake or anaesthetized. Awake patients require little to no sedation. Unlike either the LMA or COPA, placing the MNT does not require an anaesthetic dose that risks apnoea. The MNT also permits fibreoptic tracheal intubation, either orally or nasally, with the device in place. Unlike an LMA, the MNT does not restrict the size of ETT to that which fits through the lumen, nor does it require specialized equipment (i.e. the ‘Fastrack’ LMA).

The MNT also provides an alternative to the Patil intubating face-mask for fibreoptic intubation during positive pressure ventilation of the anaesthetized patient.7 The Patil mask avoids the risk of nasal bleeding, but the MNT (unlike the Patil mask) does not restrict the size of the ETT that can be used.

Using the MNT with inhalation anaesthesia to aid fibreoptic intubation has potential advantages compared with nasal cannula and i.v. anaesthesia. Greater inspired concentrations of oxygen, ability to monitor respiratory pattern, and potential for rapid conversion to positive pressure ventilation are easily possible (Fig. 2).



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Fig 2 Technique of delivering positive pressure ventilation via the MNT. The mouth and opposite nostril are closed with one hand (reproduced from Beattie3 with permission).

 
Passing devices through the nose can cause bleeding. Recognizing this, we pre-treated all patients with a nasal vasoconstrictor. In a previous series of patients managed by us with the MNT, two out of 46 patients had nasal bleeding discernible at the orifice; neither required specific treatment. In a larger series at our institution, three nosebleeds occurred in 102 patients; none required treatment (unpublished data). In our small series presented here, we noted no nasal bleeding.

We conclude that the MNT is useful for maintaining a patent airway, spontaneous ventilation, and general anaesthesia during fibreoptic intubations. It was especially useful in patients who needed, but refused, awake intubation. It can be constructed rapidly from equipment commonly found in the operating room, placement requires little or no sedation, it establishes a patent airway in a spontaneously breathing patient, and it permits delivery of an inhaled general anaesthetic during fibreoptic intubation. As with any airway device, we recommend that clinicians become familiar with its elective use before using it in an emergency.


    References
 Top
 Abstract
 Introduction
 Methods
 Discussion
 References
 
1 Elam JO, Titel JH, Feingold, Weisman H, Bauer RO. Simplified airway management during anesthesia or resuscitation: a binasal pharyngeal system. Anesth Analg 1969; 48: 307–16[Medline]

2 Weisman H, Weis TW, Elam JO, Bethune RM, Bauer RO. Use of double nasopharyngeal airways in anesthesia. Anesth Analg 1969; 48: 356–61[Medline]

3 Beattie C. The ‘modified nasal trumpet’ maneuver. Anesth Analg 2002; 94: 467–9[Abstract/Free Full Text]

4 McIntyre JWR. Oropharyngeal and nasopharyngeal airways: I (1880–1995). Can J Anaesth 1996; 43: 629–35[Abstract]

5 Vergese C, Brimacombe JR. Survey of laryngeal mask usage in 11,910 patients: safety and efficacy for conventional and unconventional usage. Anesth Analg 1996; 82: 129–33[Abstract]

6 Greenberg RS, Brimacombe J, Berry A, Gouze V, Piantadosi S, Dake EM. A randomized controlled trial comparing the cuffed oropharyngeal airway and the laryngeal mask airway in spontaneously breathing anesthetized adults. Anesthesiology 1998; 88: 970–7[CrossRef][ISI][Medline]

7 Ovassapian A, Wheeler M. Fiberoptic endoscopy-aided techniques. In: Benumof JL, ed. Airway Management: Principles and Practice. St Louis: Mosby, 1996; 290–310