Brochoscopy Intervention using Laryngeal Mask Airway in Infant for Severe Airway Stenosis

Citation: Cheng Q, Li L (2015) Brochoscopy Intervention using Laryngeal Mask Airway in Infant for Severe Airway Stenosis. Glob J Anesthesiol 2(1): 012013. DOI: 10.17352/2455-3476.000009 012 kpa; and SpO2, 92%. Laboratory investigation revealed no significant findings. After consulting with anesthesitists, endoscopists, surgeons and radiologists, EBI for tracheal stenosis was scheduled though LMA because of her poor respiratory condition.


Introduction
Fibreoptic bronchoscopy (FB) and laryngeal mask airway (LMA) have been used successfully in children since the early 1980s [1,2]. The paediatric fibreoptic bronchoscopy visa laryngeal mask airway (LMA) in general anesthesia was established in 1990s [3,4]. Although previous studies have shown some experience on FB in infant, conclusive effects on bronchoscopy intervention are unknown. We report the use of laryngeal mask airway (LMA) to guide electric bronchoscopy interventions (EBI) while maintaining an adequate depth of anesthesia and effective ventilation in small infant who was diagnosed of having severe airway stenosis from computed tomography (CT) scan.

Case Reports
A five-month-old female infant weighing 6kg, was arranged to EBI using LMA. She was hospitalized because of caugh one month ago. Preoperative examination: Karnofsky score 20 points,inspiratory stridor, intermittment cyanosis. CT and FB revealed 80% tracheal obstruction ( Figure 1A). The stenosis was arising from trachea membrance 20 mm below the vocal cord. The stenotic lesion had extended from the origin of tracheal bronchus to the carina (length of stenosis was 11 mm), without involving the carina. The luminal diameter at the narrowest of the trachea was 2 mm. arterial blood gas analysis were as follows: pH 7.35; PaCO 2 , 6.58 kpa; PaO 2 , 7.70

Technique of bronchoscopic intervention
Procedures were performed with electric flexible bronchoscopes (Pantex, Janpan, bronchoscopes of external diameters 4.9 mm and 2.8mm) through the 2 # LMA. When managing airway obstruction, endoscopists recanalized the obstructed lumen and relieve the patient's symptoms [5]( Figure 1C). Various methods for controlling the airway have been established to solve this problem, such as the electric loop, cryoprobe, argon plasma coagulation. The operation took 30 minutes ( Figure 1D). After operation, the findings of the postoperative arterial blood gas analysis were as follows: pH 7.01; PaCO 2 ,15.33KPa ; PaO 2 , 10.13KPa and SpO2, 93%.we remove LMA and insert the endotracheal 3.5 # tube. The patient was transferred to the intensive care unit. 6 hours after the surgery, endotracheal tube was removed. The pathological diagnosis is hemangioma. A week later, the patient discharged. After a year follow-up, the patient has no breath suppress symptoms.

Discussion
EBI under general anesthesia is difficult and hazardous in small infant. Although a rigid bronchoscope is suitable for examing the larynx under general anesthesia, it is more hazardous to tissues around the larynx than fiberscopic procedures. Thus, fiberoptic bronchoscopy with the LMA should fulfill both the requirements of diagnosis and of safety for children [3,6,7].
By contrast, EBI through an endotracheal tube under general anesthesia is a safe procedure, but narrow airway cannot be passed through an appropriately sized bronchoscope. The smallest bronchoscope which has a biopsy channel is 4.9 mm in diameter and endotracheal tube of at least 7 mm in diameter. This would effectively mean that transbronchial intervention could only be performed in children over 8 years of age [3]. The smallest bronchoscope with a suction channel is 2.8 mm in diameter and requires and endotracheal tube of at least 4.5 mm in diameter. The lower age limit for bronchoalveolar lavage would then be 1 years. So the size 2 LMA (internal diameter 7 mm) is suitable for use in infants.
Most centers avoid bronchoscopy in children under light sedation because the results will often remain unsatisfactory because of cough and movement. Also, in our experience, significant problems during the procedure are usually due rather to a too shallow and almost never to a too deep level of anesthesia/sedation. A recent review of this topic shows a practical approach to these procedures [8]. Even with deep sedation, protective airway reflexes must be suppressed to allow the passage of the bronchoscope through the glottis, generating a similar level of aspiration risk as during anesthesia [9]. In line with practice in children anesthesia in our department, we use general anaesthetic, rather than sedation, for all interventions. This enables better monitoring and airway control. So we also advocate that bronchoscopy interventions in children should only be performed under general anaesthetic [10].
During this case postoperative blood gas PaO 2 , PaCO 2 higher indicate that mechanical ventilation is inadequate. The reasons of inadequate ventilation include tracheal diameter thin, relative large bronchoscope, and secretions, blood, shedding tiny tissues etc. When SPO 2 lower than 95%, we stopped the intervention and begin handal ventilation until SPO 2 100%. After pause the therapy, oxygen saturation rate was 78. This indicates that infants have limited oxygen reserve, especially collapse of the small airways and an interval of hypoxemia [11].
Although this case was performed through LMA, other devices should be prepared. From our limited experience, the following features should be focused on. (1) Adjust patient, head low-feet high position, avoid aspiration. (2) Anesthesiologist should be familiar with anesthetic airway control and prepare different sizes of tubes, establish emergency airway. This is critical when managing patients with airway obstruction. (3) During interventions, certified and fully trained nurse is required to the safe procedure.
In conclusion, the LMA is useful for fiberoptic bronchoscopy of children with severe subglottic stenosis. The anesthesiologist must be responsible for the airway in the whole intervention and control the airway quickly when emergency.