postpneumonectomy syndrome ( pps ) is an ominous complication , with prevalence in children ranging from 1 in 6   to 1 in 5 pneumonectomies .
it is caused by mediastinal shift following massive lung resection that results in compression and stretching of the great vessels and airways .
it usually occurs after right pneumonectomy , performed for infections , congenital malformations , or metastatic tumours .
we report on a patient with oesophageal atresia ( oa ) who developed a pps following oa repair .
a 1-day - old girl was referred to our department for the suspect of oa .
she was born by caesarean section at 37 weeks of gestation after an uneventful pregnancy .
her birth weight was 2.1  kg and the apgar score was 7/7 at 1/5  min . on admission she was well , with normal oxygen saturation during spontaneous breathing .
chest x - rays showed the nasogastric tube folding at the level of the first thoracic vertebra and a distended stomach ( fig .
echocardiography demonstrated normal left sided aortic arch , a large patent ductus arteriosus and hypoplastic right pulmonary artery .
preoperative fiberoptic tracheoscopy was performed to exclude the presence of a tracheo - oesophageal cleft , and to measure the oesophageal gap .
the tip of the bronchoscope was placed at the level of the fistula and a contrasted naso - gastric tube was inserted in the upper pouch .
she underwent uneventful surgical ligation and section of the tof and primary oesophageal anastomosis . on post - operative day one , she had progressive clinical worsening with marked hypoxia despite mechanical ventilation .
chest x - rays showed total collapse of the right lung and right mediastinal shift ( fig .
a fiberoptic tracheobronchoscopy performed by an experienced otolaryngologist revealed a long malacic trachea , extending to the left main bronchus .
the suspect of a right oesophageal bronchus associated with the oa was confirmed by oesophagogram showing the origin of the right main bronchus from the oesophagus , caudal to the patent anastomosis ( fig .
the right lung collapse caused massive mediastinal shift and rotation , clinically mimicking a pps .
a high resolution ct scan with 3d images reconstruction showed a collapsed hypoplastic right lung with a single , small , right pulmonary artery and an associated left pulmonary artery sling ( fig .
2a ) , not visible during the pre - operative echocardiography focused to the side of the aortic arch . to push the mediastinum in the correct position ,
a 12 ch foley catheter was inserted in the right hemithorax and sterile normal saline ( 50  ml ) was infused ( fig .
d ) , and serial saline infusions were performed in the next days . in the occasion of surgical correction of the left pulmonary artery sling ( day 22 of life ) a tissue expander was inserted in the right hemithorax to stabilize the mediastinum . on post - operative day 25
, a right pneumonectomy was performed and the tissue expander was replaced with a larger one .
post - operative course was uneventful ; she was extubated on post - operative day 2 , and discharged home on post - operative day 24 .
she is alive and well at 24 months of follow - up with moderate thoracic asymmetry and good respiratory function .
we present a case of acute pps following oa repair in a patient with associated right oesophageal lung .
the association of oa with an abnormal bronchial implantation on the oesophagus is extremely rare and falls in the so - called communicating bronchopulmonary foregut malformations ( cbpfm ) . in our series of 256 patients with oa / tof consecutively treated from 1995 we found only one such patient and gou et al .
first used the term  bronchopulmonary foregut malformations  in 1968 to describe a spectrum of congenital malformations including pulmonary sequestration with or without connections to the alimentary tract .
srikanth et al . later suggested the term cbpfm to describe a segment of lung tissue connected to the foregut , and introduced a classification .
the first group of this classification is represented by sequestered lung tissue associated with oa / tof and connected to the distal oesophagus . in our patient ,
surgical repair of ea suddenly impeded the ventilation to the lung fed by the oesophageal bronchus , thereby leading to total right lung collapse and contralateral single lung ventilation .
the pathogenetic cascade is confirmed by the only reported case that did not have surgical ligation of the fistula after detection of the anomaly .
that patient s respiratory conditions remained stable because the fistula allowed airflow to the right lung . in our patient ,
the limitation of the preoperative endoscopic study to exclude a tracheo - oesophageal cleft and to define the oesophageal gap misled our intraoperative management and delayed the diagnosis of cbpfm .
a detailed tracheobronchoscopy would probably have allowed the diagnosis of cbpfm before oa repair , as suggested by the subsequent tracheobronchoscopy that showed the absence of the right main bronchus . in any case , in the event of acute worsening of clinical conditions during oa / tof repair or shortly thereafter , with unilateral total lung collapse , the presence of an associated cbpfm should always be born in mind and actively investigated .
oesophagogram is the gold - standard diagnostic test as it shows the aberrant origin of the oesophageal bronchus .
the study should be performed in lateral decubitus as the bronchus originates from the side of the oesophagus , usually the right one .
oesophagoscopy should be avoided in the acute setting as it can cause disruption of the fresh anastomosis . in our patient ,
lung resection is generally well tolerated , with good long - term outcomes . however , there are anatomic characteristics specific to children that are thought to predispose them to specific post - operative complications .
moreover , during childhood , lungs are more compliant due to the higher content of elastic tissue .
this relative flexibility of the mediastinal structures could lead to contralateral pulmonary distension after a pneumonectomy .
mediastinal shift and rotation causes compression and stretching of the great vessels and airways that in association with overdistension of the remaining lung can result in critical worsening of pulmonary function leading to major respiratory failure , the so called pps .
this condition is most frequently encountered in children than in adults for the anatomical characteristics mentioned above .
pps can occur almost immediately after pneumonectomy but is more common in the progressive and delayed form . in our patient ,
oa / tof repair was followed by acute complete right lung collapse , simulating a right pneumonectomy , with massive right - sided mediastinal shift , clinically mimicking a pps .
the left pulmonary artery sling that caused left main bronchus stenosis further worsened the clinical picture . as a consequence , both air and blood flow in the remaining left lung was acutely reduced by the mediastinal shift .
when such a clinical picture occurs in patients with group 1 cbpfm , the term pseudo - pps seems more appropriate as they do not undergo lung resection surgery .
classically , treatment of cbpfm is to resect the aberrant lung tissue with lobectomy or pneumonectomy and mediastinal repositioning using rigid prostheses ( e.g. breast prostheses ) or tissue expanders in the empty hemithorax .
reimplantation of the anomalous bronchus is the ideal management but was attempted in only one patient with cbpfm associated with oa , which was successful .
this option should be considered in patients with normal pulmonary vasculature and without lung tissue damage due to aspiration or prolonged consolidation . however , in some cases pps may be life - threatening , and its treatment requires emergency repositioning of the mediastinum in axis . in our patient , we performed an iatrogenic hydrothorax by infusing sterile normal saline in the right hemithorax , which was followed by immediate improvement of her clinical conditions .
serial infusions were performed to maintain the mediastinum in axis , which allowed the patient to sustain clinical stability and to undergo cardiac surgery . in our patient , bronchial reconstruction was not possible as definitive treatment because the right bronchus was too short , not allowing a good anastomosis with the trachea , and the lung remained collapsed too long to allow its re - expansion .
the association of oa with an abnormal bronchial implantation on the oesophagus is extremely rare and falls in the so - called communicating bronchopulmonary foregut malformations ( cbpfm ) . in our series of 256 patients with oa / tof consecutively treated from 1995 we found only one such patient and gou et al .
first used the term  bronchopulmonary foregut malformations  in 1968 to describe a spectrum of congenital malformations including pulmonary sequestration with or without connections to the alimentary tract .
srikanth et al . later suggested the term cbpfm to describe a segment of lung tissue connected to the foregut , and introduced a classification .
the first group of this classification is represented by sequestered lung tissue associated with oa / tof and connected to the distal oesophagus .
surgical repair of ea suddenly impeded the ventilation to the lung fed by the oesophageal bronchus , thereby leading to total right lung collapse and contralateral single lung ventilation .
the pathogenetic cascade is confirmed by the only reported case that did not have surgical ligation of the fistula after detection of the anomaly .
that patient s respiratory conditions remained stable because the fistula allowed airflow to the right lung . in our patient , the limitation of the preoperative endoscopic study to exclude a tracheo - oesophageal cleft and to define the oesophageal gap misled our intraoperative management and delayed the diagnosis of cbpfm .
a detailed tracheobronchoscopy would probably have allowed the diagnosis of cbpfm before oa repair , as suggested by the subsequent tracheobronchoscopy that showed the absence of the right main bronchus . in any case , in the event of acute worsening of clinical conditions during oa / tof repair or shortly thereafter , with unilateral total lung collapse , the presence of an associated cbpfm should always be born in mind and actively investigated .
oesophagogram is the gold - standard diagnostic test as it shows the aberrant origin of the oesophageal bronchus .
the study should be performed in lateral decubitus as the bronchus originates from the side of the oesophagus , usually the right one .
oesophagoscopy should be avoided in the acute setting as it can cause disruption of the fresh anastomosis . in our patient ,
lung resection is generally well tolerated , with good long - term outcomes . however , there are anatomic characteristics specific to children that are thought to predispose them to specific post - operative complications .
moreover , during childhood , lungs are more compliant due to the higher content of elastic tissue .
this relative flexibility of the mediastinal structures could lead to contralateral pulmonary distension after a pneumonectomy .
mediastinal shift and rotation causes compression and stretching of the great vessels and airways that in association with overdistension of the remaining lung can result in critical worsening of pulmonary function leading to major respiratory failure , the so called pps .
this condition is most frequently encountered in children than in adults for the anatomical characteristics mentioned above .
pps can occur almost immediately after pneumonectomy but is more common in the progressive and delayed form . in our patient ,
oa / tof repair was followed by acute complete right lung collapse , simulating a right pneumonectomy , with massive right - sided mediastinal shift , clinically mimicking a pps .
the left pulmonary artery sling that caused left main bronchus stenosis further worsened the clinical picture . as a consequence , both air and blood flow in the remaining left lung was acutely reduced by the mediastinal shift .
when such a clinical picture occurs in patients with group 1 cbpfm , the term pseudo - pps seems more appropriate as they do not undergo lung resection surgery .
classically , treatment of cbpfm is to resect the aberrant lung tissue with lobectomy or pneumonectomy and mediastinal repositioning using rigid prostheses ( e.g. breast prostheses ) or tissue expanders in the empty hemithorax .
reimplantation of the anomalous bronchus is the ideal management but was attempted in only one patient with cbpfm associated with oa , which was successful .
this option should be considered in patients with normal pulmonary vasculature and without lung tissue damage due to aspiration or prolonged consolidation . however , in some cases pps may be life - threatening , and its treatment requires emergency repositioning of the mediastinum in axis . in our patient , we performed an iatrogenic hydrothorax by infusing sterile normal saline in the right hemithorax , which was followed by immediate improvement of her clinical conditions .
serial infusions were performed to maintain the mediastinum in axis , which allowed the patient to sustain clinical stability and to undergo cardiac surgery . in our patient ,
bronchial reconstruction was not possible as definitive treatment because the right bronchus was too short , not allowing a good anastomosis with the trachea , and the lung remained collapsed too long to allow its re - expansion .
in patients with oa , the development of post - operative severe respiratory distress and unilateral lung collapse must lead to the suspect of an associated cbpfm .
neonatologists and paediatric surgeons should be aware of this rare association that may cause acute life threatening worsening of patient s clinical conditions . in the case of pps development ,
infusion of sterile normal saline in the affected hemithorax is a simple , fast and effective method that allows pushing the mediastinum in the correct position , thereby leading to dramatic improvement of the clinical conditions .
although no identifying details are reported , parents of the patient have given their informed consent .
 highlightsafter esophageal atresia repair , if postpneumonectomy syndrome develops , an associated esophageal lung must be considered.contrast esophagography , with the patient lying on the side of collapsed lung , is the optimal diagnostic study.in infants with postpneumonectomy syndrome , infusion of normal saline in the hemithorax on the side of collapsed lung is a simple , rapid , and effective method to obtain mediastinum realignment in emergency with immediate improvement of clinical conditions . 
Introduction
Case presentation
Discussion
Communicating bronchopulmonary foregut malformations
Clinical presentation
Treatment
Conclusions
Conflicts of interest
Funding
Ethical approval
Consent
Author contribution
Guarantor