Novel Position for Laryngeal Mask Airway Insertion in Patients with Postburn Contracture over Neck: A Case Series.

Difficult intubation in cases of post burn contracture over neck is a known problem. We report five cases of postburn contracture over neck, posted for scar excision and split skin grafting. Detailed preanesthetic examination and airway evaluation was done. Anticipating difficulty in conventional laryngoscopy and endotracheal intubation in these patients due restricted neck movements we planned to manage these cases under general anesthesia using classic laryngeal mask airway (LMA). Standard method of LMA insertion was unsuccessful. The patients were repositioned using shoulder elevation and jaw thrust after which LMA could be successfully inserted in these patients. The cases were subsequently managed uneventfully. Classic LMA can be used as a useful alternative in the management of difficult airway for the administration of general anesthesia. In cases where standard method is unsuccessful elevation of shoulders can help in insertion of LMA. Copyright:

INTRODUCTION

Postburn contracture over neck is challenging to anesthesiologists due to difficulty in airway management. Implications of burns such as fibrosis of tissues, distortion of landmarks, and restriction of neck movements make conventional intubation difficult.[1]

Technical advances such as fiber optic bronchoscopy have made management of difficult airway safer. However, their availability, expertise and functioning is an issue.[2] In such cases, laryngeal mask airway (LMA) can be used.

We report five cases of postburn contracture over neck, where a novel method of shoulder elevation and jaw thrust to aid successful placement of LMA was used.

CASE REPORT

Consent from patients for publishing the case report was taken. Five female patients with a history of postburn contracture over chin, neck, and chest were posted for scar excision and split skin grafting [Figures 1 and 2]. The patients had no comorbidities and blood investigations were within normal limits. Airway examination showed restricted neck movements. Thyromental and sternomental distances could not be measured due to distortion of land marks. Mouth opening and Mallampati grading were noted [Table 1]. Oral cavity examination revealed no obvious deformity due to burns. Chest X-ray and X-ray neck anterioposterior view and lateral view were taken. Consent was obtained for anesthesia and possibility of emergency tracheostomy.

Figure 1

Patient 1, Burn contracture anterior and lateral view

Figure 2

Patient 2, Burn contracture anterior and lateral view

Table 1

Details of patients

	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5
Age (years)	32	24	28	30	31
Sex	Female	Female	Female	Female	Female
Weight (kg)	50	46	44	48	52
Mouth opening (mm)	40	36	38	40	41
Mallampati score	4	4	4	4	4
LMA size used	3	3	3	3	3
History of burns	5 years	3 years	4 years	3 years 8 months	4 years 2 months
Duration of surgery (min)	240	200	210	250	180

LMA=Laryngeal mask airway

The patients were advised overnight fasting. They received oral alprazolam 0.25 mg and oral ranitidine 150 mg the night before and on the morning of surgery. Before the surgery, landmarks were marked over the neck after visualizing the X-ray taking into account the possibility of emergency cricothyrotomy or tracheostomy. Surgeon was prepared for excision of scar in case of failure to pass LMA. A surgical team for possible emergency tracheostomy was also prepared.

In operating room, patients were placed supine with head rested over a head ring with height of approximately 7 cm. After adequate intravenous (i.v.) access, application of standard monitors, premedication and preoxygenation, patients were induced with i.v. Propofol titrated to loss of eyelash reflex and relaxation of jaw. If required i.v. Propofol 1 mg.kg−1was added to achieve adequate level of anesthesia in case of patient coughing, gagging, or moving during LMA insertion. Bag mask ventilation was checked before attempting LMA insertion. Posterior surface of LMA cuff was lubricated and insertion was attempted by an experienced anesthesiologist. Standard technique for LMA insertion was unsuccessful, after which 180° rotation technique was tried, which also failed. Before third attempt, an assistant standing on the right side of patient facing anesthesiologist lifted both the shoulders so that sternum and external auditory meatus were at the same level. The stability of head was maintained with head ring. Another assistant standing on the left side of patient facing the anesthesiologist performed jaw thrust and LMA insertion was attempted again. The insertion of LMA was successful in this position. Correct placement was confirmed by chest auscultation and end tidal carbon dioxide waveform. Oxygen saturation was maintained during the whole event. The later intraoperative and postoperative periods were uneventful.

DISCUSSION

Various options of anesthetic management in burn contracture over neck are described like, awake fiber optic guided intubation, tumescent anesthesia, video-assisted laryngoscope for intubation, Airtraq, supraglottic airway device, preinduction scar release under local anesthesia, and ketamine followed by direct laryngoscopy and endotracheal intubation, intubation with the help of special laryngoscope blades, retrograde intubation.[3] All our patients had severely restricted neck movements and their Mallampati score was 4. Hence, we expected difficulty or impossibility with conventional laryngoscopy and endotracheal intubation.

Fiber optic bronchoscopy is the gold standard for managing anticipated difficult airway.[2] However, fiber optic bronchoscope was unavailable with us. Difficult airway management algorithms recommend use of supra glottis airway devices for the management of anticipated and unanticipated airway management.[4] Taking into consideration, the presence of available resources and our past experience in managing similar cases of difficult airway using LMA, we planned to manage the cases under general anesthesia using classic LMA.

Classic LMA is a cheap, useful airway device which has the advantage of easy insertion.[5] In a meta-analysis conducted by Park et al., they concluded that 90° rotation after lateral insertion and 180° rotation technique may be considered as an useful alternative when predicting or encountering difficulty in inserting supraglottis airway devices.[6] Hence, when standard technique of LMA insertion failed we used the 180° rotation technique. However, we failed to place the LMA in position using this method also. This could be because of folding of the airway cuff over epiglottis. We attributed this to patient position rather than the technique of insertion. Sniffing position is considered the most ideal position for LMA insertion.[7] In our patients, the sniffing position could not be achieved as extension of head was not possible. Hence, we tried LMA insertion in a different position. Gupta et al. in their study have observed that LMA cuff leak is more in neck flexion.[8] Lebowitz et al. in a study on 189 adult patients observed that the elevation of head and shoulder by any means that brings the patient's sternum onto the horizontal plane of external auditory meatus improves laryngoscopic view for tracheal intubation in obese and nonobese patients.[9] Study by Eglen et al. on 180 adult patients using three different techniques of LMA insertion has found that successful insertion time was significantly shorter when triple maneuver is applied. Triple airway maneuver involves extension of head, mouth opening, and jaw thrust.[10] In our patients head tilt was not possible, but jaw thrust could be applied. Hence, we opted for elevation of shoulders along with jaw thrust which we believe helped in better alignment of airway axis due to which successful placement of LMA became possible. We would like to highlight utility of this position in cases of difficult LMA insertion.

CONCLUSION

LMA can be used as an useful alternative for management of difficult airway. The elevation of shoulders and application of jaw thrust can help in successful placement of LMA in difficult cases like postburn contracture over neck where sniffing position is not possible.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.