Bronchovenous fistula – leading to fatal massive systemic air embolism during cardiopulmonary bypass
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《血管的通路杂志》
Department of Thoracic and Cardiovascular Surgery, Christian Medical College & Hospital, Vellore – 632 004, India
Abstract
Objective: We report a case of a bronchovenous fistula in an adult who could not be resuscitated following a mitral valve replacement. Methods: A 39-year-old man underwent a mitral valve replacement for severe mitral stenosis and regurgitation. Following uneventful valve replacement surgery, and while attempting to wean the patient off bypass, we encounted a bronchovenous fistula following mechanical ventilation. Results: This patient could not be resuscitated following surgery because of persistent air embolism in the patient. Conclusion: Systemic air embolism has been reported to occur following penetrating chest injury. Especially, when the entry and the exit sites have been over sewn and either a marked Valsalva maneuver by the patient (such as coughing or straining) or forced positive pressure ventilation in excess of 60 torr occurs, systemic air embolism can be created from bronchiolar–alveolar to pulmonary venous fistula. It has also been described in blunt thoracic trauma. Bronchovenous fistula is occasionally encountered in neonates due to ventilation injuries with high ventilatory pressures, especially with underlying lung pathology like respiratory distress syndrome, necessitating such high ventilatory pressures. To our knowledge, this is the first such case reported in the literature.
Key Words: Bronchovenous fistula
1. Introduction
Bronchovenous fistula is a rare complication following cardiopulmonary bypass. We report a case of a patient who could not be resuscitated following the development of the bronchovenous fistula while weaning off cardiopulmonary bypass following a mitral valve replacement [1,2].
2. Case report
A 39-year-old gentleman who was suffering from severe mitral stenosis and regurgitation was taken up for mitral valve replacement. He also had a history of severe bilateral varicosities involving the great saphenous system. At the time of surgery it was noticed that all of the tissues were very friable. Even the aortic and venous purse string sutures cut through very easily. He was put on bypass following aortic and bicaval cannulation and the heart arrested using cold sanguineous cardioplegia. On opening the left atrium, the mitral valve was stenosed and incompetent with thickened fibrosed valve leaflets. The valve was excised and replaced using a Starr Edwards Mechanical prosthesis sparing the posterior leaflet. The valve was seated, tied and checked. The left atrium was closed and after routine de-airing maneuvers the cross clamp was released. The heart picked up well in sinus rhythm and manual ventilation was commenced. After a few minutes, the anesthetist noticed difficulty in ventilating the patient and they had to use greater manual pressures to ventilate the patient. They then noticed bright blood in the endotracheal tube. Suddenly we found air bubbling through the left atrial suture line with each ventilation. Simultaneously there was air bubbling from the sides of the aortic and the root cannulae. The head end was immediately lowered further and the patient was ventilated using 100% FIO2 at a lower ventilatory pressure. However, none of these measures were effective and the air continued to bubble through the left atrium in large volumes. We cross clamped the aorta, arrested the heart again and opened the left atrium. We found air gushing through the right lower lobe pulmonary vein with each squeeze of the bag by the anaesthetist. We closed the left atrium, released the cross clamp and tried de-airing measures again, but air continued to leak through the left atrial suture line and the heart gradually slowed and distended. Eventually, all efforts were in vain and the patient expired on the table [4,5].
3. Discussion
Mortality for systemic air embolism is very high and ranges from 48 to 80% in adults [3]. The pathophysiology of bronchovenous fistula is considered to be due to alveolar rupture into small veins and capillaries [6]. Air can enter through a direct iatrogenic connection between the lung parenchyma and the left atrium [7]. In our case no Swan Ganz catheter was introduced which could have caused this complication. Recently, Dr Reinhartz et al. [8] reported a case of successful resuscitation in a neonate following bronchovenous fistula following cardiopulmonary bypass. The etiology of that was suspected to be barotrauma due to high ventilatory pressures.
The diagnosis of massive air embolism can be self-evident as was in our case. However, if the fistula is small, an echocardiogram can show air entering into the left atrium. Trans-esophageal echocardiography is considered to be invaluable in the operating theater as was evident in the case managed successfully as reported by Dr Reinhartz et al. The management of bronchovenous fistula involves low head tilt, 100% FIO2 along with other measures like low ventilatory pressures and ionotropic support [8]. Extra corporeal membrane oxygenation [8] and selective single lung ventilation have been used successfully in a few cases of iatrogenic bronchovenous fistula. This can allow sufficient time for the air leak in the affected lung to seal off. Single lung ventilation was initially suggested by Moon and Pintadori [9] and, of late, by Ho and Ling [3]. In our case, we were not aware of this entity and we were not sure of the cause of this problem. We feel that this occurred because of barotrauma due to high pressure caused by manual ventilation. If we had known, probably selective left lung ventilation and collapsing of the right lung could have saved our patient. The mortality for massive air embolism as was seen in our patient continues to remain extremely high. No autopsy was performed on our patient as the relatives were not agreeable for the same.
References
Graham JM, Beall AC Jr, Mattox KL, Vaughn GD. Systemic air embolism following penetrating trauma to the lung. Chest 1977;72:449–454.
Graham JM, Mattox KL, Feliciano DV, Beall AC Jr. Air embolism following penetrating thoracic trauma. Curr Concepts Trauma Care Fall 1979;7–9.
Ho Am, Ling E. Systemic air embolism after lung trauma. Anaesthesiology 1999;90:564–575.
Gregory GA, Tooley WH. Gas embolism in hyaline membrane disease. New Eng J Med 1970;282:1141–1142.
Lee SK, Tanewell AK. Pulmonary vascular embolism in newborn. Arch Disease Child 1989;64:507–510.
Klein JF, Hilfer C, Shahrivar F. Neonatal radiology casebook; pulmonary venous gas embolism. J Perin 1990;10:328–329.
Kole SD, Saksena DS, Oswal DH. Fatal cerebral air embolism during open-heart surgery caused by lung parenchyma to left atrium communication. J Heart Valve disease 1994;3:583–584.
Reinhartz O, Anil M, De Silva FH. Management of neonatal bronchovenous fistula after cardiopulmonary bypass. Ann Thorac Surg 2002;73:1320–1322.
Moon RE, Piantadori CA. Initial treatment of patients with extensive trauma. (letter). New Eng J Med 1991;325:1444–1445.(Hari Krishna Doshi, Roy T)
Abstract
Objective: We report a case of a bronchovenous fistula in an adult who could not be resuscitated following a mitral valve replacement. Methods: A 39-year-old man underwent a mitral valve replacement for severe mitral stenosis and regurgitation. Following uneventful valve replacement surgery, and while attempting to wean the patient off bypass, we encounted a bronchovenous fistula following mechanical ventilation. Results: This patient could not be resuscitated following surgery because of persistent air embolism in the patient. Conclusion: Systemic air embolism has been reported to occur following penetrating chest injury. Especially, when the entry and the exit sites have been over sewn and either a marked Valsalva maneuver by the patient (such as coughing or straining) or forced positive pressure ventilation in excess of 60 torr occurs, systemic air embolism can be created from bronchiolar–alveolar to pulmonary venous fistula. It has also been described in blunt thoracic trauma. Bronchovenous fistula is occasionally encountered in neonates due to ventilation injuries with high ventilatory pressures, especially with underlying lung pathology like respiratory distress syndrome, necessitating such high ventilatory pressures. To our knowledge, this is the first such case reported in the literature.
Key Words: Bronchovenous fistula
1. Introduction
Bronchovenous fistula is a rare complication following cardiopulmonary bypass. We report a case of a patient who could not be resuscitated following the development of the bronchovenous fistula while weaning off cardiopulmonary bypass following a mitral valve replacement [1,2].
2. Case report
A 39-year-old gentleman who was suffering from severe mitral stenosis and regurgitation was taken up for mitral valve replacement. He also had a history of severe bilateral varicosities involving the great saphenous system. At the time of surgery it was noticed that all of the tissues were very friable. Even the aortic and venous purse string sutures cut through very easily. He was put on bypass following aortic and bicaval cannulation and the heart arrested using cold sanguineous cardioplegia. On opening the left atrium, the mitral valve was stenosed and incompetent with thickened fibrosed valve leaflets. The valve was excised and replaced using a Starr Edwards Mechanical prosthesis sparing the posterior leaflet. The valve was seated, tied and checked. The left atrium was closed and after routine de-airing maneuvers the cross clamp was released. The heart picked up well in sinus rhythm and manual ventilation was commenced. After a few minutes, the anesthetist noticed difficulty in ventilating the patient and they had to use greater manual pressures to ventilate the patient. They then noticed bright blood in the endotracheal tube. Suddenly we found air bubbling through the left atrial suture line with each ventilation. Simultaneously there was air bubbling from the sides of the aortic and the root cannulae. The head end was immediately lowered further and the patient was ventilated using 100% FIO2 at a lower ventilatory pressure. However, none of these measures were effective and the air continued to bubble through the left atrium in large volumes. We cross clamped the aorta, arrested the heart again and opened the left atrium. We found air gushing through the right lower lobe pulmonary vein with each squeeze of the bag by the anaesthetist. We closed the left atrium, released the cross clamp and tried de-airing measures again, but air continued to leak through the left atrial suture line and the heart gradually slowed and distended. Eventually, all efforts were in vain and the patient expired on the table [4,5].
3. Discussion
Mortality for systemic air embolism is very high and ranges from 48 to 80% in adults [3]. The pathophysiology of bronchovenous fistula is considered to be due to alveolar rupture into small veins and capillaries [6]. Air can enter through a direct iatrogenic connection between the lung parenchyma and the left atrium [7]. In our case no Swan Ganz catheter was introduced which could have caused this complication. Recently, Dr Reinhartz et al. [8] reported a case of successful resuscitation in a neonate following bronchovenous fistula following cardiopulmonary bypass. The etiology of that was suspected to be barotrauma due to high ventilatory pressures.
The diagnosis of massive air embolism can be self-evident as was in our case. However, if the fistula is small, an echocardiogram can show air entering into the left atrium. Trans-esophageal echocardiography is considered to be invaluable in the operating theater as was evident in the case managed successfully as reported by Dr Reinhartz et al. The management of bronchovenous fistula involves low head tilt, 100% FIO2 along with other measures like low ventilatory pressures and ionotropic support [8]. Extra corporeal membrane oxygenation [8] and selective single lung ventilation have been used successfully in a few cases of iatrogenic bronchovenous fistula. This can allow sufficient time for the air leak in the affected lung to seal off. Single lung ventilation was initially suggested by Moon and Pintadori [9] and, of late, by Ho and Ling [3]. In our case, we were not aware of this entity and we were not sure of the cause of this problem. We feel that this occurred because of barotrauma due to high pressure caused by manual ventilation. If we had known, probably selective left lung ventilation and collapsing of the right lung could have saved our patient. The mortality for massive air embolism as was seen in our patient continues to remain extremely high. No autopsy was performed on our patient as the relatives were not agreeable for the same.
References
Graham JM, Beall AC Jr, Mattox KL, Vaughn GD. Systemic air embolism following penetrating trauma to the lung. Chest 1977;72:449–454.
Graham JM, Mattox KL, Feliciano DV, Beall AC Jr. Air embolism following penetrating thoracic trauma. Curr Concepts Trauma Care Fall 1979;7–9.
Ho Am, Ling E. Systemic air embolism after lung trauma. Anaesthesiology 1999;90:564–575.
Gregory GA, Tooley WH. Gas embolism in hyaline membrane disease. New Eng J Med 1970;282:1141–1142.
Lee SK, Tanewell AK. Pulmonary vascular embolism in newborn. Arch Disease Child 1989;64:507–510.
Klein JF, Hilfer C, Shahrivar F. Neonatal radiology casebook; pulmonary venous gas embolism. J Perin 1990;10:328–329.
Kole SD, Saksena DS, Oswal DH. Fatal cerebral air embolism during open-heart surgery caused by lung parenchyma to left atrium communication. J Heart Valve disease 1994;3:583–584.
Reinhartz O, Anil M, De Silva FH. Management of neonatal bronchovenous fistula after cardiopulmonary bypass. Ann Thorac Surg 2002;73:1320–1322.
Moon RE, Piantadori CA. Initial treatment of patients with extensive trauma. (letter). New Eng J Med 1991;325:1444–1445.(Hari Krishna Doshi, Roy T)