The laryngeal mask airway in fibreoptic bronchoscopy

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] .

The Tools of the Trade - Uses of Flexible Bronchoscopy

Bronchoscopes have markedly improved the diagnosis as well as therapy in pediatric pulmonary disorders. Two types of bronchoscopes are available; flexible and rigid, with their own advantages and disadvantages. Depending on the clinical need and availability of skills, choice is made between the two. Typically, rigid scopes are largely used by the surgeons (pediatric or otolayngologists) while flexible bronchoscope stays in the domain of the pediatric pulmonologist and intensivists. Rigid scopes may be more versatile than flexible bronchoscopes in removing the foreign bodies from the airway. Flexible bronchoscopes on the other hand can even be introduced through an endotracheal tube. At times, use of both scopes may be required in a given patient for optimal results. Bronchoscopes give us a means to visualize the inside of the airway, which can be very informative for assessing various pathologies affecting the airways. Apart from the visualization of the parts of the airway tree and their structure as well as patency, it can also be used to take tissue biopsy specimens, collect secretions from the airways and bronchoalveolar lavage which can also get cellular elements from the distal alveoli. In the past few decades, more and more instruments are being used for expanding the utility of flexible bronchoscope for interventions ranging from bronchial toilet, foreign body removal, airway stenting and lasers or cryotherapy for airway lesions. The perinatologists have opened up more vistas and thrown newer challenges for using fiberoptic bronchoscopy (FB) for in utero tracheal occlusion in cases with diaphragmatic hernia. The vast applications of this tool makes it very relevant to pulmonary investigations and therapeutics.

How to enter the pediatric airway for bronchoscopy

BACKGROUND

Bronchoscopies are performed in childhood for diagnostic reasons (e.g. evaluation of stridor, unexplained cough, possible malformations) and therapeutic reasons (e.g. foreign body removal, management of the difficult airway).

METHODS

Various procedures of entering the pediatric airways are presented, based on an overview of the literature and the experience of the authors.

RESULTS

The advantages and disadvantages of direct fibreoptic bronchoscopy, bronchoscopy via face mask, via laryngeal mask airway, via tracheal tube, and for combined flexible and rigid bronchoscopy are discussed. In addition, practical aspects of bronchoscopy are considered, including local anesthesia, oxygen supplementation, monitoring, antibiotic treatment.

CONCLUSIONS

Although inspection of the pediatric airways has become a well-accepted routine procedure with a high diagnostic yield, and bronchoscopies are well tolerated, it is important that the most appropriate means of access to the airways is chosen according to the indications and the age of the child.

Pediatric fiberoptic bronchoscopy with a laryngeal mask airway

BACKGROUND AND OBJECTIVES

Bedside flexible fiberoptic bronchoscopy (FFB) with sedation has been recognized as a diagnostic modality in children. In certain circumstances, general anesthesia with endotracheal intubation is advocated. This study evaluates the usefulness of the laryngeal mask airway (LMA) as an alternative to endotracheal intubation during pediatric FFB.

DESIGN, SETTING, AND PATIENTS

Between July 1995 and June 2000, we studied 92 children (51 girls; age range, 1 through 15 years) in the operating theater of a major tertiary children's hospital. The LMA was used in children with atelectasis, diffuse infiltrates, and those who required BAL under general anesthesia. The size of the LMA was chosen to accommodate a bronchoscope appropriate for the child's weight and age.

RESULTS

Procedures were well tolerated, no complications were observed, and oxygen saturation exceeded 95% in all patients. Major findings included mucoid impaction and purulent bronchial secretions, and BAL was successfully accomplished in all individuals.

CONCLUSIONS

Diagnostic BAL or extraction of mucous plugs should be accomplished with optimal control of the airway under general anesthesia. The use of the LMA during FFB is safe, provides excellent patient comfort, and should be utilized as an alternative to endotracheal intubation.

Pediatric bronchoscopy

Diagnostic flexible endoscopy for pediatric respiratory diseases is performed in many centers. Technical advances have resulted in performance of interventional bronchoscopies, and new diagnostic indications are being explored. Indications with documented clinical benefit include congenital or acquired progressive or unexplained airway obstruction. Pulmonary infections in immunodeficient children who do not respond to empirical antibiotic treatment may be diagnosed by bronchoscopy and bronchoalveolar lavage (BAL). The potential usefulness of bronchoscopy and BAL for managing chronic cough, wheeze, or selected cases with asthma or cystic fibrosis requires further study. The use of transbronchial biopsies (TBB) is established in pediatric lung transplantation. The role of TBB in the diagnosis of chronic interstitial lung disease in children remains to be determined. For a number of interventional applications, rigid endoscopy is required, and pediatric bronchoscopists should be trained in its use. Complications in pediatric bronchoscopy are rare, but severe nosocomial infection or overdosing with local anesthetics has occurred. The issues of quality control, video documentation, interobserver variability of findings, and educational standards will have to be addressed in the future as bronchoscopy use becomes less restricted to only large pediatric pulmonary units.

Bronchoscopic removal of bronchial foreign bodies through the laryngeal mask airway in pediatric patients

The laryngeal mask airway was used to perform fiberoptic removal of bronchial foreign bodies (peanuts) in two pediatric patients. Laryngeal mask airway offers easy access to the airway, safe respiratory management and direct visualization of the airway during bronchoscopic procedures. Laryngeal mask airway allows the use of larger bronchoscopes than can usually be used for children when bronchoscopy is performed through an endotracheal tube. In each case, the peanuts were removed safely and easily using a Fogarty catheter through the fiberoptic bronchoscope. These cases suggest that laryngeal mask airway is useful in maintaining a secure airway during the removal of bronchial foreign bodies in children.

Laryngeal mask airway facilitated fibreoptic bronchoscopy in infants

PURPOSE

To assess the efficacy of the laryngeal mask airway (LMA) for fibreoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) in infants.

METHODS

Observations were made in 19 consecutive infants undergoing FOB under general anaesthesia (GA) plus topical local anaesthesia. Anaesthesia was induced with N2O, O2, and halothane or sevoflurane except in two patients who received propofol and one who received thiopentone. Anaesthesia was maintained with oxygen and either sevoflurane, halothane, desflurane, or propofol infusion. No neuromuscular blockers were used. Size #1 or #2 LMAs were used through which a 3.5 mm fibreoptic bronchoscope was introduced. ECG, noninvasive blood pressure, pulse oximetry and, PETCO2 were measured. Intra- and post-procedural complications were recorded.

RESULTS

Mean age was 6 months; mean weight was 6.6 kg. Chronic wheezing was the indication for FOB in eight patients. Minor complications occurred in five patients: difficult LMA placement in one patient required changing size from #2 to #1; two patients had laryngospasm and bronchospasm that resolved with deepened anaesthesia and nebulised bronchodilator; one patient had transient arterial O2 desaturation, responding to increased FIO2, and one patient required tracheal intubation because ventilation via LMA became inadequate.

CONCLUSION

The minor complications observed were similar to other series and did not result in morbidity or mortality. We feel that GA via LMA facilitates safe FOB in infants. It affords excellent airway management, a quiet patient, and passage of a large fibreoptic bronchoscope for better imaging and suction channel required for BAL.