Use of tracheobronchography as a diagnostic tool in ventilator-dependent infants

Airway Problems in Neonates-A Review of the Current Investigation and Management Strategies

Airway problems in the neonatal population are often life threatening and raise challenging issues in diagnosis and management. The airway problems can result from congenital or acquired lesions and can be broadly classified into those causing obstruction or those due to an abnormal "communication" in the airway. Many different investigations are now available to identify the diagnosis and quantify the severity of the problem, and these tests can be simple or invasive. Bronchography and bronchoscopy are essential to determine the extent and severity of the airway problem and to plan treatment strategy. Further imaging techniques help to delineate other commonly associated abnormalities. Echocardiography is also important to confirm any associated cardiac abnormality. In this review, the merits and disadvantages of the various investigations now available to the clinician will be discussed. The current therapeutic strategies are discussed, and the review will focus on the most challenging conditions that cause the biggest management conundrums, specifically laryngotracheal cleft, congenital tracheal stenosis, and tracheobronchomalacia. Management of acquired stenosis secondary to airway injury from endotracheal intubation will also be discussed as this is a common problem. Slide tracheoplasty is the preferred surgical option for long-segment tracheal stenosis, and results have improved significantly. Stents are occasionally required for residual or recurrent stenosis following surgical repair. There is sufficient evidence that a multidisciplinary team approach for managing complex airway issues provides the best results for the patient. There is ongoing progress in the field with newer diagnostic tools as well as development of innovative management techniques, such as biodegradable stents and stem cell-based tracheal transplants, leading to a much better prognosis for these children in the future.

Tracheobronchomalacia diagnosed by tracheobronchography in ventilator-dependent infants

BACKGROUND

Tracheobronchomalacia prevalence in premature infants on prolonged mechanical ventilation is high.

OBJECTIVE

To examine the prevalence of tracheobronchomalacia diagnosed by tracheobronchography in ventilator-dependent infants, and describe the demographic, clinical and dynamic airway characteristics of those infants with tracheobronchomalacia.

MATERIALS AND METHODS

This retrospective review studies 198 tracheobronchograms performed from 1998 to 2011 in a cohort of 158 ventilator-dependent infants <2 years of age. Dynamic airway assessment during tracheobronchography determined the optimal positive end-expiratory pressure to maintain airway patency at expiration in those infants with tracheobronchomalacia.

RESULTS

Tracheobronchograms were performed at a median age of 52 weeks post menstrual age. The primary diagnoses in these infants were bronchopulmonary dysplasia (53%), other causes of chronic lung disease of infancy (28%) and upper airway anomaly (13%). Of those with bronchopulmonary dysplasia, 48% had tracheobronchomalacia. Prematurity (P=0.01) and higher baseline - pre-tracheobronchogram positive end-expiratory pressure (P=0.04) were significantly associated with tracheobronchomalacia. Dynamic airway collapse during tracheobronchography showed statistically significant airway opening at optimal positive end-expiratory pressure (P < 0.001). There were no significant complications noted during and immediately following tracheobronchography.

CONCLUSION

The overall prevalence of tracheobronchomalacia in this cohort of ventilator-dependent infants is 40% and in those with bronchopulmonary dysplasia is 48%. Infants born prematurely and requiring high pre-tracheobronchogram positive end-expiratory pressure were likely to have tracheobronchomalacia. Tracheobronchography can be used to safely assess the dynamic function of the airway and can provide the clinician the optimal positive end-expiratory pressure to maintain airway patency.

Radiology in paediatric non-traumatic thoracic emergencies

Non-traumatic thoracic emergencies in children are very frequent, and they usually present with breathing difficulties. Associated symptoms may be feeding or swallowing problems or less specific general symptoms such as fever, sepsis or chest pain. The emergencies always require a rapid diagnosis to establish a medical or surgical intervention plan, and radiological imaging often plays a key role. Correct interpretation of the radiological findings is of great importance in diagnosing and monitoring the illness and in avoiding serious complications. Plain radiography with fluoroscopy still remains the most important and frequently used tool to gain information on acute pulmonary problems. Ultrasound is the first choice for the detection and treatment of simple and complicated pleural effusions. Cross-sectional techniques such as multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) are mainly used to study pulmonary/mediastinal masses and congenital abnormalities of the great vessels and the lungs. This article will discuss the choice of imaging technique, the urgency of radiological management and the imaging characteristics of acquired and congenital causes of non-traumatic thoracic emergencies. They represent common conditions involving the respiratory tract, chest wall and the oesophagus, as well as the less frequent causes such as tumours and manifestations of congenital malformations.

What does imaging the chest tell us about bronchopulmonary dysplasia?

Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Chest imaging is important in making the diagnosis of BPD, and in assessing for complications. More recently computerised tomography (CT) scanning has provided insights in to the pathophysiology of BPD. Studies in infants, young and school age children as well as young adults have consistently demonstrated abnormalities in the peripheral lung, possibly related either to small airway or alveolar disease. Advances in CT scanning may increase the clinical role for this modality, in addition newer techniques such as hyperpolarised gas magnetic resonance imaging are likely to provide further insights in to the nature of BPD and its effects on the developing lung.

Computed tomography versus bronchography in the diagnosis and management of tracheobronchomalacia in ventilator dependent infants

AIM

To assess the relative accuracy of dynamic spiral computed tomography (CT) compared with tracheobronchography, in a population of ventilator dependent infants with suspected tracheobroncho-malacia (TBM).

SETTING

Paediatric intensive care unit in a tertiary teaching hospital.

PATIENTS AND METHODS

Infants referred for investigation and management of ventilator dependence and suspected of having TBM were recruited into the study. Tracheobronchography and CT were performed during the same admission by different investigators who were blinded to the results of the other investigation. The study was approved by the hospital research ethics committee, and signed parental consent was obtained.

RESULTS

Sixteen infants were recruited into the study. Fifteen had been born prematurely, and five had cardiovascular malformations. In 10 patients there was good or partial correlation between the two investigations, but in six patients there was poor or no correlation. Bronchography consistently showed more dynamic abnormalities, although CT picked up an unsuspected double aortic arch. Radiation doses were 0.27-2.47 mSv with bronchography and 0.86-10.67 mSv with CT.

CONCLUSIONS

Bronchography was a better investigation for diagnosing TBM and in determining opening pressures. Spiral CT is unreliable in the assessment of TBM in ventilator dependent infants. In addition, radiation doses were considerably higher with CT.

Tracheobronchial intervention in children

Disorders of the major airways in children are often difficult to treat. Recent advances in interventional radiology are proving useful, for both assessment of the severity of the problem and treatment. Flexible bronchoscopy and bronchography are essential tools for diagnosis, intervention and follow-up. Echocardiography, computed tomography and magnetic resonance imaging may also be important for the evaluation of cardiovascular anomalies, which are often associated with airway obstruction. Surgery remains the first line of treatment for most congenital abnormalities of the airway and for cardiac anomalies that cause airway compression. Balloon dilatation and stenting are helpful in certain other conditions, as well as in children whose airway problem is not fully corrected by surgery. A multidisciplinary approach is required, with input from pediatric cardiothoracic surgeons, radiologists, radiographers, otolaryngologists, pulmonologists, anesthesiologists, intensivists, physiotherapists and liaison nurses.

Tracheobronchial malacia and stenosis in children in intensive care: bronchograms help to predict oucome

BACKGROUND

Severe tracheobronchial malacia and stenosis are important causes of morbidity and mortality in children in intensive care, but little is known about how best to diagnose these conditions or determine their prognosis.

METHODS

The records of all 62 children in whom one or both of these conditions had been diagnosed by contrast cinetracheobronchography in our intensive care unit in the period 1986-95 were studied.

RESULTS

Seventy four per cent of the 62 children had congenital heart disease; none was a preterm baby with airways disease associated with prolonged ventilation. Fifteen of the children had airway stenosis without malacia; three died because of the stenosis and two died from other causes. Twenty eight of the 47 children with malacia died; only eight children survived without developmental or respiratory handicap. All children needing ventilation for malacia for longer than 14 consecutive days died if their bronchogram showed moderate or severe malacia of either main bronchus (15 cases), or malacia of any severity of both bronchi (three additional cases); all children needing ventilation for malacia for longer than 21 consecutive days died if their bronchogram showed malacia of any severity of the trachea or a main bronchus (three additional cases). These findings were strongly associated with a fatal outcome (p<0.00005); they were present in 21 children (all of whom died) and absent in 26 (of whom seven died, six from non-respiratory causes). They had a positive predictive value for death of 100%, but the lower limit of the 95% confidence interval was 83.9% so up to 16% of patients meeting the criteria might survive.

CONCLUSION

In this series the findings on contrast cinetracheobronchography combined with the duration of ventilation provided a useful guide to the prognosis of children with tracheobronchomalacia. The information provided by bronchoscopy was less useful.