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From the Department of Anesthesiology, British Columbia’s Children’s Hospital and University of British Columbia, Vancouver, British Columbia, Canada.
Address correspondence to:: Dr. J. Mark Ansermino, Department of Anesthesiology, University of British Columbia, British Columbia’s Children’s Hospital, 4480 Oak Street, Room 1L7, Vancouver, British Columbia V6H 3V4, Canada. Phone: 604-875-2345; E-mail: anserminos{at}yahoo.ca
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Abstract |
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Methods: Canadian pediatric anesthesiologists were invited to complete a web survey. Respondents selected their preferred anesthetic and airway management techniques in six clinical scenarios. The clinical scenarios involved airway management for cases where the difficulty was in visualizing the airway, sharing the airway and accessing a compromised airway.
Results: General inhalational anesthesia with spontaneous respiration was the preferred technique for managing difficult intubation especially in infants (90%) and younger children (97%), however, iv anesthesia was chosen for the management of the shared airway in the older child (51%) where there was little concern regarding difficulty of intubation. Most respondents would initially attempt direct laryngoscopy for the two scenarios of anticipated difficult airway (73% and 98%). The laryngeal mask airway is commonly used to guide fibreoptic endoscopy. The potential for complete airway obstruction would encourage respondents to employ a rigid bronchoscope as an alternate technique (17% and 44%).
Conclusion: Inhalational anesthesia remains the preferred technique for management of the difficult pediatric airway amongst Canadian pediatric anesthesiologists. Intravenous techniques are relatively more commonly chosen in cases where there is a shared airway but little concern regarding difficulty of intubation. In cases of anticipated difficult intubation, direct laryngoscopy remains the technique of choice and fibreoptic laryngoscopy makes a good alternate technique. The use of the laryngeal mask airway was preferred to facilitate fibreoptic intubation.
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Introduction |
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Recent reviews have provided guidelines for developing an approach to the pediatric patient with a difficult airway.4,5 Use of the flexible fibreoptic bronchoscopic (FOB) has become common practice amongst anesthesiologists and the availability of airway adjuncts such as laryngeal mask airway (LMA) and lighted stylet widespread.6
Providing evidence for the best method of dealing with a difficult pediatric airway remains a challenge. Most anesthesiologists will be faced with few cases each year, particularly with the reduction in the need for endotracheal intubation brought about by the use of the LMA. Conducting randomized controlled trials is very difficult due to the small numbers of cases in each centre and therefore we rely on the advice of individual experts with unique experience2,3 or on reviews of case studies4 to provide us with practice guidelines. Surveying current practice and opinion of experienced clinicians can help to identify changes in practice, reinforce practice guidelines and assess the impact of new techniques and pharmacological approaches. In this study, we wished to understand how experienced pediatric anesthesiologists in Canada would plan to approach six defined difficult pediatric airway scenarios.
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Methods |
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, they involved airway management for cases where the difficulty was in visualizing the airway (scenarios 1 and 2), sharing the airway (scenarios 3 and 4), and accessing a compromised airway (scenarios 5 and 6).
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Respondents were also asked whether or not they would use a spontaneously breathing technique or controlled ventilation with or without a muscle relaxant. In keeping with the ASA difficult airway algorithm, the respondents were required to select their primary and alternate airway management technique. The choices for airway management technique included: direct laryngoscopy; FOB with or without a LMA; blind nasal; blind intubation through a LMA; lighted stylet; rigid fibreoptic laryngoscopes; CombitubeTM (Life-Assist, Inc., CA, USA); rigid bronchoscope; retrograde wire; and surgical airway. Finally, respondents were asked to indicate, on a scale of 1 (least) to 5 (most), their level of experience and expectation of success with their choice of airway technique.
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Results |
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, indicate that the majority of the respondents were experienced pediatric anesthesiologists practicing in academic centres in Ontario, Alberta and British Columbia.
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Anesthetic method
The majority of respondents chose to give a general anesthetic for all cases except the laryngeal fracture (scenario 5), in which 46% chose an awake technique for establishing control of the airway. For the Pierre Robin cases (scenarios 1 and 2), almost all respondents chose to give a general anesthetic (95% and 95%) using an inhalational agent (89% and 84%) while maintaining spontaneous respiration (89% and 87%). For the shared airway cases, general anesthesia using inhalational agents was most commonly chosen in scenario 3 (76%), but in scenario 4, for the older child, iv and inhalational agents were chosen equally. Lastly, almost all chose to give a general anesthetic using an inhalational agent (97%), while keeping the patient with potential epiglottitis breathing spontaneously (95%). The results for preferred anesthetic method are displayed in Table III.
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FOB was favoured as an alternate technique or as the primary technique when the airway was known to be difficult. When a FOB technique was chosen, the use of a laryngeal mask to facilitate intubation was preferred. The results for preferred airway management techniques in scenarios 1, 2, 5 and 6 are displayed in Table IV.
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Discussion |
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General anesthesia prior to intubation was by far the most widely chosen anesthetic method for pediatric difficult airway patients. The use of awake techniques, frequently employed in adult practice,2,11 are not favoured in infants and young children, as cooperation is needed to produce topical anesthesia of the airway and obtain adequate conditions for endoscopic visualization of the airway. In the case of the ten-year-old with a traumatized airway (scenario 5), asleep and awake methods were chosen equally, which may reflect the fact that the child was potentially at an age to cooperate with an awake intubation.
Anesthetic method
The finding that inhalational anesthesia with spontaneous ventilation was used for most difficult airway cases concurs with the recommendations by most authors.12,13 However, in the shared airway scenarios (scenarios 3 and 4), a relatively greater number of respondents chose an iv technique to allow airway manipulation by the surgeon. Potential advantages of total iv techniques in diagnostic and therapeutic airway endoscopy include: steady level of anesthesia, independent of ventilation; and reduced exposure of operating room personnel to waste anesthetic agents.9 The use of muscle relaxants for airway management was also more prevalent in these scenarios. The traditional teaching for airway endoscopy for an inhaled foreign body, is to maintain spontaneous ventilation to avoid dislodging the foreign body deeper into the respiratory tract. However, in a retrospective review of anesthetic experience with bronchial or tracheal foreign body removal, neither spontaneous nor controlled ventilation was associated with an increased incidence of adverse events.14
Airway management technique
In cases of possible difficult intubation, direct laryngoscopy remains the primary technique of choice. The efficacy of a LMA both in providing a good airway in the pediatric patient with a difficult airway as well as a conduit for FOB has been well established in recent studies15,16 and it was commonly chosen to guide fibreoptic endoscopy. The rigid bronchoscope was used fairly commonly (44%) for cases with the potential for airway obstruction (scenarios 3, 5 and 6). There was no difference in the level of experience or anticipated success when this technique was chosen despite the latter two scenarios being rare. We would therefore assume that the choice of rigid bronchoscopy implied the presence of an ENT surgeon.
In the scenarios of difficulty in airway visualization, FOB was chosen as the initial technique by 22% in scenario 1 and 53% in scenario 2. This difference may be due to the different developmental stages of the patients in the two cases, greater familiarity with direct laryngoscopy or the desire to grade the laryngoscopic view.
As an alternate technique, a strong majority chose FOB for both scenario 1 and scenario 2. A significant proportion of those choosing FOB as an alternate technique for managing potential epiglottitis indicated that they had little or no experience of this condition. While there are no absolute contraindications to FOB, pharyngeal or laryngeal masses may distort anatomy and make FOB more difficult.15 The use of rigid bronchoscopy or surgical airway is recommended as an alternate technique for managing failed intubation in acute epiglottitis12,13 and as the primary technique for immediate airway management of blunt laryngotracheal trauma in children.7
The reliance on FOB in many of the clinical scenarios emphasizes the need to have suitable pediatric fibreoptic endoscopes available in locations dealing with these types of cases and need for appropriate training and maintenance of skills for FOB. The findings suggest that the number of cases available for training is limited and, thus, mandates the use of FOB in normal individuals and simulated scenarios for adequate training.
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Limitations |
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While selection bias may be present for both web surveys and mail surveys, the authors made numerous attempts to contact Canadian pediatric anesthesiologists to ensure equal chances of participating across this study’s population. A random sample may have been collected using another modality but a web survey was preferable for several reasons. Firstly, it removed geographical constraints, allowing the investigators to sample pediatric anesthesiologists from across Canada. Secondly, the media richness of the survey was ideal for presenting respondents with clinical scenarios; pictures, video and audio can be incorporated. Thirdly, the modality allowed respondents to complete the survey at their convenience. Fourthly, the automated data collection offered time and resource efficiencies to the researcher. Lastly, the automatic summary of the responses and import to a spreadsheet prevented transcription error during data entry and facilitated data analysis.
In summary, general inhalational anesthesia with spontaneous respiration was the preferred technique for management of difficult intubation particularly in infants and younger children, however, iv anesthesia was chosen for the management of the shared airway where there was little concern regarding difficulty of intubation.
FOB was used most commonly as an alternate technique or as a primary technique for a known difficult intubation. When FOB was chosen, the majority of clinicians tended to use a LMA as a conduit for the bronchoscope indicating that this technique is now firmly established in the approach to the difficult pediatric airway. A rigid bronchoscope should be available when the risk for complete airway obstruction is present. This survey of expert clinicians illustrates existing practices and may be helpful in planning an approach to the difficult pediatric airway.
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Footnotes |
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References |
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2 Walker RW, Darowski M, Morris P, Wraith JE. Anaesthesia and mucopolysaccharidoses. A review of airway problems in children. Anaesthesia 1994; 49: 1078–84.[Medline]
3 Gunawardana RH. Difficult laryngoscopy in cleft lip and palate surgery. Br J Anaesth 1996; 76: 757–9.
4 Frei FJ, Ummenhofer W. Difficult intubation in paediatrics. Paediatr Anaesth 1996; 6: 251–63.[Medline]
5 Wheeler M. Management strategies for the difficult pediatric airway. Anesthesiol Clin North Am 1998; 16: 743–61.
6 Jenkins K, Wong DT, Correa R. Management choices for the difficult airway by anesthesiologists in Canada. Can J Anesth 2002; 49: 850–6.
7 Gold SM, Gerber ME, Shott SR, Myer CM III. Blunt laryngotracheal trauma in children. Arch Otolaryngol Head Neck Surg 1997; 123: 83–7.[Abstract]
8 Merritt RM, Bent JP, Porubsky ES. Acute laryngeal trauma in the pediatric patient. Ann Otol Rhinol Laryngol 1998; 107: 104–6.[Medline]
9 Verghese ST, Hannallah RS. Pediatric otolaryngologic emergencies. Anesthesiol Clin North Am 2001; 19: 237–56.[Medline]
10 Levy RJ, Helfaer MA. Pediatric airway issues. Crit Care Clin 2000; 16: 489–504.[Medline]
11 Rosenblatt WH, Wagner PJ, Ovassapian A, Kain ZN. Practice patterns in managing the difficult airway by anesthesiologists in the United States. Anesth Analg 1998; 87: 153–7.
12 Badgwell JM, McLeod ME, Friedberg J. Airway obstruction in infants and children. Can J Anaesth 1987; 34: 90–8.
13 Benjamin B. Anesthesia for pediatric airway endoscopy. Otolaryngol Clin North Am 2000; 33: 29–47.[Medline]
14 Litman RS, Ponnuri J, Trogan I. Anesthesia for tracheal or bronchial foreign body removal in children: an analysis of ninety-four cases. Anesth Analg 2000; 91: 1389–91.
15 Auden SM. Flexible fiberoptic laryngoscopy in the pediatric patient. Anesthesiol Clin North Am 1998; 16: 763–93.
16 Walker RW. The laryngeal mask airway in the difficult paediatric airway: an assessment of positioning and use in fibreoptic intubation. Paediatr Anaesth 2000; 10: 53–8.[Medline]
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