Bronchoscopic airway evaluation facilitated by the laryngeal mask airway in pediatric patients

Pediatric interventional bronchoscopy: from early limitations to achievable opportunities

PURPOSE OF REVIEW

The rapid evolution of bronchoscopy equipment and technologies, from the introduction of the 1.1 mm flexible cryoprobe to the use of navigational and robotic bronchoscopy, has afforded unprecedented opportunities for pediatric advanced diagnostic and interventional bronchoscopy. While there is growing interest among pediatric pulmonologists to incorporate these new techniques into their practice, the current pediatric landscape is characterized by few practicing interventional bronchoscopists, scant published literature, and no formal training programs.

RECENT FINDINGS

While the majority of the published literature consists of case reports and small case series, the increased application of new techniques is starting to yield larger and more structured studies that will be able to provide more objective commentary on the proposed indications, safety, and efficacy of such techniques in the pediatric population.

SUMMARY

For many decades, progress in pediatric advanced diagnostic and interventional bronchoscopy was slow and deliberate, limited by the lack of appropriately sized equipment and experienced interventional bronchoscopists. The current opportunities afforded require equal, or perhaps even more, vigilance as pediatric pulmonologists employ new equipment and technologies and define new practices and standards of care. Importantly, this review is meant to serve as a general conspectus of pediatric advanced diagnostic and interventional bronchoscopy and not a consensus guideline for the performance of advanced or even routine bronchoscopy in the pediatric population. For technical standards of pediatric bronchoscopy, refer to existing guidelines [1,2] .

Comparison of laryngeal mask airway and endotracheal intubation in gynecological cancer operation

Endotracheal intubation (ETI) and laryngeal mask airway (LMA) in terms of hemodynamics and reaction were compared. A total of 54 general anesthesia patients were randomized into two groups with 27 cases in each group. Acceleration index (ACI), cardiac index (CI), cardiac output (CO), left cardiac work (LCW), systemic circulation resistance (SVR), mean arterial pressure (MAP), heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded at 12 time-points: before surgery (T0), start effect (T1), lost consciousness (T2), before ETI or LMA (T3), 1 min (T4), 3 min (T5), 5 min (T6) after ETI or LMA, the beginning of surgery (T7), 30 min (T8), 1 hour (T9) after surgery, the end of surgery (T10) and extubation (T11). In each group these indexes went down and rose up gently during surgery except for T4 (intubation) and T11 (extubation) in ETI. These indexes reached the highest at T11 (extubation). This is due to the stimulus on mucosa and muscle of root of tongue, throat and epiglottis from the windpipe. The stimulus excites sympathetic nerve and increases the release of catecholamine. As a result, the heart beats faster and blood pressure rises. However, the range in the LMA group is smaller especially at T4 and T11. This is most likely due to LMA not stimulating the trachea. SVR, MAP, HR, SBP and DBP were lower in LMA with statistical significance in some time-points. The other indexes such as ACI, CI, CO and LCW were significantly higher in LMA (P<0.05). These results indicated that LMA can be suitable for use in general anesthesia for less stimulation. The airway with LMA in patients undergoing gynecological cancer operation is better than ETI in keeping stable hemodynamics and producing less anesthetic complications with smooth recovery from general anesthesia.

Use of a Helium-Oxygen Mixture to Facilitate Ventilation During Bronchoscopy Through a Laryngeal Mask Airway

Purpose: Flexible fiberoptic bronchoscopy may be performed in infants and children for various diagnostic and therapeutic purposes. In infants and children, general anesthesia may be used to facilitate the procedure. When general anesthesia is used, a laryngeal mask may be used to control the airway. However, as the passage of the bronchoscope decreases the cross-sectional airway inside the laryngeal mask airway (LMA) for gas exchange, increases in respiratory resistance may occur. We present our experience with the use of a helium—oxygen mixture to facilitate bronchoscopy through an LMA during general anesthesia in infants and children. Methods: We retrospectively reviewed changes in tidal volume, respiratory rate, and transcutaneous carbon dioxide (TC-CO2) during 3 phases of general anesthetic care. Phase 1 was pressure support breathing of an air—oxygen mixture through an LMA during sevoflurane anesthesia prior to the start of bronchoscopy, phase 2 was with the bronchoscope inserted through the LMA during pressure support ventilation of sevoflurane in an air—oxygen mixture, and phase 3 was with the bronchoscope inserted through the LMA during pressure support breathing of sevoflurane in a helium—oxygen mixture. Results: The study cohort included 6 patients, ranging in age from 14 to 49 months. There was a statistically significant increase in respiratory rate, increase in TC-CO2, and decrease in tidal volume with the insertion of the bronchoscope through the LMA when compared to baseline values (phase 2 vs phase 1). These values returned to values that were comparable to the baseline values when a helium—oxygen mixture was administered (phase 1 vs phase 3). Conclusions: A helium—oxygen mixture decreases resistance to gas flow during bronchoscopy through an LMA in infants and children receiving general anesthesia with sevoflurane and pressure support ventilation.

Airway Management of the Severely Retrognathic Child: Use of the Laryngeal Mask Airway

Successful airway management of an infant or child with moderate to severe retrognathia first requires recognition of a potential problem. If the child cannot be intubated in a standard fashion, the use of a laryngeal mask airway (LMA) should be considered. We describe two cases wherein a toddler and an infant with severe retrognathia failed multiple attempts at traditional intubation. Both had an anterior larynx and hypoplasia of the mandible. In both cases, a subsequent LMA was successfully placed. The severely retrognathic newborn or child presents to the physician a unique challenge in airway management. Techniques to manage this difficult pediatric airway are different from those used in the adult. Otolaryngologists should be aware of this intubation technique and include it in their armamentarium of airway-management strategies. The LMA is not recommended as the technique of choice for securing a difficult airway, but it is an effective alternative when indicated, and it might be life-saving.

Pediatric airway issues

Airway management in the pediatric patient requires an understanding and knowledge of the differences and characteristics unique to the child and infant. New and exciting techniques are currently being explored and developed for management of the pediatric airway. Technology in the area of imaging has allowed clinicians to better visualize the airway and aberrations of it. Presently, there are many different modes and routes of ventilation and oxygenation that are being applied to the pediatric patient for different disease states. Work continues to probe for methods and ways that will allow us to take care of infants and children better and to provide the safest and most effective means of delivering that care. No doubt, there will be more advances and exciting ideas to come that lead to better management of the pediatric airway.

Anesthetic care for the child with Morquio syndrome: general versus regional anesthesia

Morquio syndrome is a subtype of the mucopolysaccharidoses (MPS IV) characterized by the intracellular accumulation of keratin sulfate. Anesthetic issues related to the primary disease process include infiltration of tissues with keratin sulfate leading to distortion of upper airway anatomy with difficult or impossible endotracheal intubation, infiltration of the cervical spine with odontoid hypoplasia placing these patients at risk for atlanto-axial subluxation and quadriparesis, as well as alterations in cardiorespiratory function. Two children with Morquio syndrome who required anesthetic care during lower extremity orthopedic procedures are presented. The anesthetic implications of Morquio syndrome are reviewed. General anesthesia was used in one case, whereas continuous spinal anesthesia, which was used in the second case, is reported for the first time in a child with mucopolysaccharidoses.

The laryngeal mask airway in fibreoptic bronchoscopy

A large series of patients is reported in whom the laryngeal mask airway was used to perform fibreoptic bronchoscopy. It allows direct visualisation of the airways during spontaneous respiration. It has enabled bronchoalveolar lavage and bronchography to be performed in children as young as 6 months and transbronchial biopsies in children as young as 4 years.