Comparison of oral intubation using flexible fibreoptic bronchoscope with or without rigid cervical collar: A clinical study

Abstract

Background: Device like fibreoptic bronchoscope is gold standard for difficult intubation situations. It can be performed by both orotracheal and nasotracheal route. But, through nasal route there are more chances of nasal bleeding and pressure necrosis while through oral route there is only one problem, which is clearing of upper airway for bronchoscope. Manoeuvres like jaw thrust and chin lift are very useful in clearing upper airway for bronchoscope. The aim of this study was to compare ease of oral intubation using flexible fibreoptic bronchoscope with or without rigid cervical collar, in terms of need of manoeuvres: Jaw thrust and Chin lift. Materials and Methods: 25 patients in age range 20-50 years, of ASA ? - II, and of either sex undergoing elective surgery under general anaesthesia were randomly allocated into each group. There were two groups: Group A (Rigid Cervical Collar) and group B (Without Collar). Intubating condition was assessed in between these groups with need of manoeuvres like jaw thrust and chin lift. Quantitative data i.e. age, weight, thyromental distance and sternomental distance were presented as mean value and standard deviation. Intergroup comparison of quantitative data was done by t-test and probability was considered to be significant if less than <0.05. Categorical data i.e. sex, ASA grade, Mallampati grade and need of manoeuvres were presented as number and were compared among groups using Chi-square test. P < 0.05 was considered statistically significant. Results: There was significant (P < 0.05) difference between group A and group B in terms of use of manoeuvres for ease of intubation and clearing upper airway. In group B, need of jaw thrust and chin lift for clearing airway is significantly (P < 0.05) higher than collar group. Conclusion: We concluded that as far as the oral intubation with flexible fibreoptic bronchoscope is concerned, rigid cervical collar is very useful tool for making intubation easier.

Keywords

Airway - fibreoptic bronchoscope - intubation - jaw thrust - rigid cervical collar

INTRODUCTION

Airway problems are the most common cause of morbidity and mortality due to anaesthesia. With the possibility of difficult intubation (5.8%), “cannot intubate” (≤0.35%), or “cannot intubate - cannot ventilate” (≤0.02%) situations, every anaesthesiologist must be prepared to deal with these airway abnormalities.[1] [2] [3] Difficult airway problem can be due to any of the following reasons- limited oropharyngeal space, decreased atlanto-occipital extension, decreased submandibular compliance and decreased pharyngeal space.[4] [5] [6] [7] Flexible fibreoptic bronchoscope is the most viable option available for the anaesthesiologist to manage such difficult airway problems.[8]

With flexible fibreoptic bronchoscope, intubation can be performed either by orotracheal route or by nasotracheal route. Through nasal route, there are more chances of various complications like epistaxis (most common with an incidence of 18-66%),[9] [10] turbinectomy or retropharyngeal dissection.[11] [12] Blood in the airways can produce a dramatic deterioration in conditions by obscuring the view during fibrescopy and by aspiration of blood into lungs.[13] Though these problems can be reduced with local application of vasoconstrictive drugs, or softening of the tube, or use of a nasopharyngeal airway as a pathfinder,[14] but are not entirely avoidable. While through oral route there is only one problem which is clearing of upper airway for bronchoscope.

During general anaesthesia, approximation of soft palate, tongue and epiglottis to the posterior pharyngeal wall occurs after administration of induction anaesthetic agents (with or without muscle relaxants).[15] Due to little space left in oropharynx for manoeuvring distal flexi-tip of fibreoptic bronchoscope, there is difficulty in locating glottic opening.[16] To solve this problem, several manoeuvres (jaw thrust,[17] [18] [19] lingual traction,[20] [21] etc.) and aid of airway intubators[22] [23] [24] (such as Ovassapian, Berman and Williams) have been tried. Sole use of intubating airways does not clear pathway for fibreoptic and required multiple manipulation.[21] [25] [26] [27]

There have been no controlled trials assessing the relative effectiveness of rigid cervical collar as an aid in opening up the oropharyngeal space in anaesthetised patients. It would be useful to know the additional role of cervical collar, as this information might enable anaesthesiologists to perform fibreoptic orotracheal intubation more swiftly and reliably. Therefore, this study was aimed to compare ease of oral intubation using flexible fibreoptic bronchoscope with or without rigid cervical collar, in terms of need of manoeuvres: Jaw thrust and Chin lift.

MATERIALS AND METHODS

After obtaining approval by Institution’s Research Ethical Committee and written informed consent, 50 patients scheduled for various elective surgical procedures requiring orotracheal intubation for general anaesthesia were enrolled. Patients in age range 20-50 years, of ASA (American Society of Anaesthesiologist) I - II, and of either sex were included in study. Patients with ASA physical status III, IV, V, or with anticipated intubation difficulty (Mallampati grade 4, thyromental distance <6 cm, sternomental distance <12 cm), or with a history reactive airway disease, gastro-oesophageal reflux, cervical spine pathology, airway distortion or trauma and major organ dysfunction were excluded from study. It was a hospital-based, randomised, single-blind, comparative, interventional type of clinical trial, conducted between 1 Jan 2013 to 31 Dec 2013.

The allocation sequence was generated using a randomisation technique (chit and box method). Patients were randomised in two groups of 25 each- group A (with rigid cervical collar) and group B (without rigid cervical collar). Before induction of anaesthesia, patient’s fasting status (8 h fasting) was confirmed. All patients received standardised general anaesthesia. Standard monitoring included ECG, non-invasive arterial pressure, SpO_2, EtCO₂ (end tidal carbon dioxide) and measurement of volatile anaesthetic levels. Bispectral index (BIS) (Aspect Medical Systems, Norwood, MA, USA) monitoring was utilised in all patients when available. Patients were premedicated with glycopyrrolate (0.005 mg/kg I.V.) and fentanyl citrate (2 μg/kg I.V.). Induction was done with propofol 2 mg/kg infused I.V. slowly and was titrated to induce anaesthesia in a dose sufficient to produce loss of verbal response. After induction of anaesthesia, all patients were manually ventilated with face mask with 1% isoflurane in oxygen. Neuromuscular blocking agent (rocuronium 1 mg/kg I.V.) was administered after checking adequacy of mask ventilation. If any difficulty was encountered in mask ventilation, the patient was excluded from study. Tracheal intubation was not performed until the BIS score had decreased below 60, and additional dose of propofol were administered to increase the depth of anaesthesia if required.

After the onset of neuromuscular block, tracheal intubation was performed with endotracheal tube (Male -8.0 mm ID, Female -7.5 mm ID) by flexible fibreoptic bronchoscope. For oral intubation with fibreoptic bronchoscope, modified Berman’s airway was used as an aid in all patients. An appropriate sized rigid cervical collar (Ambulance Collar, MGRM Medicare Limited, Hyderabad, India) was placed as per manufacturer’s instructions in group A. To perform manoeuvres (jaw thrust and chin lift) for fibreoptic intubation, we required a second assistant to place both hands behind the angle of the mandible bilaterally, with thumbs beneath chin, and gently pull forward with visible displacement of the chin forward and upward. Tube position was confirmed by auscultation and confirmed by EtCO₂ tracings. After successful intubation, the endotracheal tube was connected to the circle breathing system of the anaesthesia machine for intermittent positive pressure ventilation. Anaesthesia was maintained with isoflurane/N₂O: O₂ (60%:40%). Subsequent management was left to the discretion of the anaesthesiologist providing care to the patient. Data were collected in form of need of manoeuvres (Jaw thrust and Chin lift)- Yes/No. All the intubations were performed by a single anaesthesiologist who was familiar and trained with intubation using fibreoptic bronchoscope. Any patient who required more than one attempt to achieve successful intubation was excluded from study.

Statistical analysis

The sample size was calculated to be 25 subjects in each group with alpha error 0.05 and power 80%. Sample size calculation was based on pilot study on 12 patients, with need of manoeuvres as the primary outcome. Sample size calculation and analysis of the statistical data obtained from study was carried out by statistical programming software Statistical Package for the Social Sciences - SPSS Statistics Version 17.0.0 (SPSS Inc., Chicago, Illinois, USA). Quantitative data i.e. age, weight, thyromental distance and sternomental distance were presented as mean value and standard deviation. Intergroup comparison of quantitative data was done by student’s t-test and statistical significance was considered at P < 0.05. Categorical data (or qualitative data) i.e. sex, ASA grade, Mallampati grade and need of manoeuvres (jaw thrust and chin lift) were presented as number and were compared among groups using Chi square test. P < 0.05 was considered statistically significant.

RESULTS

Patient’s morphometric characteristics and airway assessment parameters are shown in [Table 1]. There was no statistically significant difference in intergroup comparison of demographic variables. Comparative observation of difficult intubation predicators (Mallampati grade, thyromental distance and sternomental distance) among the study population in both groups also showed statistically insignificant difference (P > 0.05).

Table 1 Intergroup comparison of morphometric characteristics and airway parameters

	Group A (with collar)	Group B (without collar)	Significance (P value)
* Qualitative data (i.e. sex, ASA grade, Mallampati grade) are presented as numbers and quantitative data (i.e. age, weight, thyromental distance, sternomental distance) are presented as mean ±SD. NS: Not significant, S: Significant, P <0.05 –Significant
Age (years)	38.32±8.20	36.12±9.51	NS (0.385378)
Sex (male/female)	17/8	16/9	NS (0.765291)
Weight (Kg)	67.68±8.97	63.32±8.14	NS (0.078171)
ASA grade (1/2)	13/12	12/13	NS (0.777297)
Mallampati grade (1/2/3)	14/9/2	17/7/1	NS (0.646083)
Thyromental distance (cm)	8.21±1.03	8.57±1.13	NS (0.244608)
Sternomental distance (cm)	15.7±2.18	17±2.43	NS (0.066949)

Intergroup comparison of need of manoeuvres is shown in [Figure 1] and [Table 2]. There was statistically significant (P = 0.0018) difference between group A and group B in terms of use of manoeuvres (jaw thrust and chin lift) for ease of intubation and clearing upper airway. In group B need of jaw thrust and chin lift for clearing airway was 76%, while in collar group, it was only 32%.

Figure 1: Percentage need of manoeuvres in Group A (with cervical collar) and in Group B (without cervical collar)

Table 2 Intergroup comparison of need of manoeuvres (jaw thrust and chin lift)

	N = 25		Total Significance (P value)
	Group A (with collar)	Group B (without collar)
*Qualitative data (i.e. need of manoeuvres) are presented as numbers. P is calculated by Chi square test. P <0.05 –Significant
Need of manoeuvres (jaw thrust and chin lift)	8	19	27	Significant (0.001801)
No need of manoeuvres (jaw thrust and chin lift)	17	6	23
Total	25	25	50

Episodes of desaturation (SpO₂ < 90%), failure to intubate and airway trauma were not seen in any of the study subject.

DISCUSSION

In recent advances, flexible fibreoptic intubation is an essential expertise for an airway management specialist, as found useful in several situations like difficult airway, cervical spine risk, one-lung isolation, endotracheal tube (ETT) exchange and tracheo-bronchoscopy. After determination of fibreoptic intubation as the appropriate choice, we must decide whether to use a nasal or oral approach. In general, the angle of curvature of the ETT (channel) naturally approximates that of the patient’s upper airway therefore the nasal route is easier for fibreoptic intubation. But oral fibreoptic intubation has its advantages as it can be performed in patients who have contraindication for nasal application of vasoconstrictors (i.e. parturient, some heart disease patients) or having any bleeding tendency or coagulation disorders.[28]

This clinical trial was aimed to identify obstacles that might occur during oral fibreoptic intubation and also attempted to alleviate these obstacles with help of manoeuvres or cervical collar. In anaesthetised patient, muscle tone is reduced after induction which leads to posterior displacement of the soft palate, base of tongue and epiglottis and causes approximation to posterior pharyngeal wall,[15] [29] ultimately occluding pathway for fibrescope. Roberts et al.[17], Hartley et al.,[18] and Lucas et al.[19] found in their studies that jaw thrusting was very helpful manoeuvre for clearing airway to perform fibrescopy. While Benumof et al.,[30] found triple airway manoeuvre (chin lift, extension at atlanto-occipital joint and anterior displacement of the mandible) as an effective approach to clear the path. Durga et al.,[31] reported that both lingual traction and jaw thrust were effective manoeuvres for clearance of airway, and jaw thrust was more effective at epiglottic level.

In our study, we demonstrated that application of rigid cervical collar act as an aid for oral fibreoptic intubation with significantly less need of manoeuvres like jaw thrust and chin lift for clearing of upper airway. At soft palate level, apposition of the tongue to uvula base and soft palate was avoided with help of intubating airway, as a result of this, fibrescope was passed to one side of uvula base without any difficulty. At epiglottic level, when the epiglottis was apposed to the posterior pharyngeal wall, passage of the fibreoptic beneath the tip of epiglottis became possible with application of cervical collar (particularly in group A patients) or with help of manoeuvres- jaw thrusting and chin lifting (mainly in group B patients).

Forward movement of jaw during thrusting leads to widening of the oropharyngeal cavity and opens the laryngeal aperture, thus easing insertion of a fibreoptic bronchoscope into the trachea.[32] [33] But jaw thrusting also causes significant movement of cervical spine.[34] While our study demonstrated that rigid cervical collar, which is commonly used to provide adequate cervical immobilisation to avoid further devastating neurological outcomes,[35] markedly reduced the requirement of manoeuvres for oral fibrescopy without cervical spine movement which can be useful particular in patients with cervical spine injury. The study showed that jaw thrust with chin lift was very effective way of clearing of airway both at soft palate and epiglottic levels. We did experience difficulty during railroading of endotracheal tube over fibreoptic bronchoscope in some patients of both groups and this difficulty was sorted out by 90° anticlockwise rotation of the tube over cord as this solution was reported by several studies.[36] [37]

In this study, we didn’t include patients with difficult intubation possibility. So at present, it is not known whether application of manoeuvres with airway intubators or use of cervical collar with airway intubators is the more reliable way of airway clearance required to perform oral fibreoptic intubation of patients known to be an intubation difficulty. Further clinical work would be required to review this possibility.

When oral fibreoptic intubation is chosen, satisfactory airway clearance can be secured with use of intubating airway and cervical collar, as a better alternative to various manoeuvres. Performing oral fibrescopy with manoeuvres required a second assistant and significant movement of cervical spine too; both can be avoided with help of cervical collar. With the use of rigid cervical collar, we can fulfil two aims. First is stabilisation of neck (which is very important in a case cervical trauma to avoid further deterioration) during intubation and second is easy fibreoptic oral intubation without chin lift and jaw thrust.

No conflict of interest has been declared by the author(s).

• REFERENCES

• 1 Shiga T, Wajima Z, Inoue T, Sakamoto A. Predicting difficult intubation in apparently normal patients: A meta-analysis of bedside screening test performance. Anesthesiology 2005; 103: 429-37
• 2 Crosby ET, Cooper RM, Douglas MJ, Doyle DJ, Hung OR, Labrecque P. et al. The unanticipated difficult airway with recommendations for management. Can J Anaesth 1998; 45: 757-76
• 3 Benumof JL. Difficult laryngoscopy: Obtaining the best view. Can J Anaesth 1994; 41 (5 Pt 1) 361-5
• 4 Bainton CR. Models to facilitate the learning of fiberoptic technique. Int Anesthesiol Clin 1994; 32: 47-55
• 5 Bainton CR. Difficult intubation: What's the best test?. Can J Anaesth 1996; 43: 541-3
• 6 Stackhouse RA, Bainton CR. Difficult airway management. In: Hughes SC, Rosen M, Levinson G. editors. Anesthesia for Obstetrics. 4th ed.. Baltimore: Williams and Wilkins; 2001. p. 375-90
• 7 Stackhouse RA, Marks JD, Bainton CR. Performing fiberoptic endotracheal intubation: Clinical aspects. Int Anesthesiol Clin 1994; 32: 57-73
• 8 Ovassapian A. Fiberoptic tracheal intubation in adults. In: Ovassapian A. editor. Fiberoptic Endoscopy and the Difficult Airway. 2nd ed.. Philadelphia: Lippincott-Raven; 1996
• 9 Kim YC, Lee SH, Noh GJ, Cho SY, Yeom JH, Shin WJ. et al. Thermosoftening treatment of the nasotracheal tube before intubation can reduce epistaxis and nasal damage. Anesth Analg 2000; 91: 698-701
• 10 Tintinalli JE, Claffey J. Complications of nasotracheal intubation. Ann Emerg Med 1981; 10: 142-4
• 11 Moore DC. Middle turbinectomy: A complication of IMPROPER nasal intubation?. Anesthesiology 2000; 92: 1504-5
• 12 Williams AR, Burt N, Warren T. Accidental middle turbinectomy: A complication of nasal intubation. Anesthesiology 1999; 90: 1782-4
• 13 Coe TR, Human M. The peri-operative complications of nasal intubation: A comparison of nostril side. Anaesthesia 2001; 56: 447-50
• 14 Smith JE, Reid AP. Identifying the more patent nostril before nasotracheal intubation. Anaesthesia 2001; 56: 258-62
• 15 Nandi PR, Charlesworth CH, Taylor SJ, Nunn JF, Dore CJ. Effect of general anaesthesia on the pharynx. Br J Anaesth 1991; 66: 157-62
• 16 Mason RA. Learning fibreoptic intubation: Fundamental problems. Anaesthesia 1992; 47: 729-31
• 17 Roberts JT. Preparing to use the flexible fiber-optic laryngoscope. J Clin Anesth 1991; 3: 64-75
• 18 Hartley M, Morris S, Vaughan RS. Teaching fibreoptic intubation. Effect of alfentanil on the haemodynamic response. Anaesthesia 1994; 49: 335-7
• 19 Lucas DN, Yentis SM. A comparison of the intubating laryngeal mask tracheal tube with a standard tracheal tube for fibreoptic intubation. Anaesthesia 2000; 55: 358-61
• 20 Cole AF, Mallon JS, Rolbin SH, Ananthanarayan C. Fiberoptic intubation using anesthetized, paralyzed, apneic patients: Results of a residency training program. Anesthesiology 1996; 84: 1101-6
• 21 Hakala P, Randell T, Valli H. Laryngoscopy and fibreoptic intubation in acromegalic patients. Br J Anaesth 1998; 80: 345-7
• 22 Berman RA. A method for blind intubation of the trachea or oesophagus. Anesth Analg 1977; 56: 866-7
• 23 Ovassapian A. A new fiberoptic intubating airway. Anesth Analg 1987; Suppl 66: S132
• 24 Williams RT, Maltby JR. Airway intubator. Anesth Analg 1982; 61: 309
• 25 Hakala P, Randell T. Comparison between two fibrescopes with different diameter insertion cords for fibreoptic intubation. Anaesthesia 1995; 50: 735-7
• 26 Randell. Valli H, Hakal P. Comparison between the Ovassapian intubating airway and the Berman intubation airway in fibreoptic intubation. Eur J Anaesth 1997; 14: 380-4
• 27 Aoyama K, Seto A, Takenaka I. Simple modification of the Ovassapian fiberoptic intubating airway. Anesthesiology 1999; 91: 897
• 28 Stackhouse RA. Fiberoptic airway management. Anesthesiology Clin North Am 2002; 20: 930-51
• 29 Boidin MP. Airway patency in the unconscious patient. Br J Anaesth 1985; 57: 306-10
• 30 Benumof JL. Nonintubation management of the airway: Mask ventilation. In: Benumof JL. editor. Airway Management: Principles and Practice. 1st ed.. St Louis: Mosby; 1996. p. 233
• 31 Durga VK, Millns JP, Smith JE. Manoeuvres used to clear the airway during fibreoptic intubation. Br J Anaesth 2001; 87: 207-11
• 32 Aoyama K, Takenaka I, Nagaoka E, Kadoya T. Jaw thrust maneuver for endotracheal intubation using a fiberoptic stylet. Anesth Analg 2000; 90: 1457-8
• 33 Murashima K, Fukutome T. Effect of jaw-thrust manoeuvre on the laryngeal inlet. Anaesthesia 1998; 53: 203-4
• 34 Wong DM, Prabhu A, Chakraborty S, Tan G, Massicotte EM, Cooper R. Cervical spine motion during flexible bronchoscopy compared with the Lo Pro GlideScope. Br J Anaesth 2009; 102: 424-30
• 35 Hastings RH, Kelly SD. Neurologic deterioration associated with airway management in a cervical spine injured patient. Anaesthesiology 1993; 78: 580-3
• 36 Schwartz D, Johnson C, Roberts J. A maneuver to facilitate flexible fiberoptic intubation. Anesthesiology 1989; 71: 470-1
• 37 Koga K, Asai T, Latto IP, Vaughan RS. Effect of size of a tracheal tube and the efficacy of the use of the laryngeal mask for fibrescope-aided tracheal intubation. Anaesthesia 1997; 52: 131-5