Year : 2023 | Volume
| Issue : 1 | Page : 77-79
Cause of profound hypoxemia following a bilateral bidirectional Glenn shunt: Clue suggested by agitated saline echo contrast
Madan M Maddali1, Pravin Saxena1, Khalid S Al Alawi2, Abdoulah Mohsen3
1 Department of Cardiac Anesthesia, National Heart Center, Royal Hospital, Muscat, Sultanate of Oman
2 Department of Pediatric Cardiology, National Heart Center, Royal Hospital, Muscat, Sultanate of Oman
3 Department of Cardiothoracic Surgery, National Heart Center, Royal Hospital, Muscat, Sultanate of Oman
Madan M Maddali
Senior Consultant in Anesthesia, National Heart Center, Royal Hospital, P. B.No: 1331, P.C: 111, Seeb, Muscat
Sultanate of Oman
Source of Support: None, Conflict of Interest: None
|Date of Submission||08-May-2022|
|Date of Decision||09-May-2022|
|Date of Acceptance||09-May-2022|
|Date of Web Publication||02-Jan-2023|
Following a bilateral bidirectional Glenn shunt, a child had persistent hypoxemia. Agitated saline contrast injection into the jugular vein during transesophageal echocardiography displayed a rapid appearance of saline particles in the cardiac chambers suggesting the presence of pulmonary arteriovenous malformations. However, the clinical picture was not in agreement and an angiographic contrast injection during an immediate cardiac catheterization revealed the underlying pathology which was immediately corrected surgically.
Keywords: Contrast media, echocardiography/methods, heart bypass, hypoxia/diagnostic imaging, hypoxia/etiology, microbubbles, pulmonary artery/diagnostic imaging, right/methods
|How to cite this article:|
Maddali MM, Saxena P, Al Alawi KS, Mohsen A. Cause of profound hypoxemia following a bilateral bidirectional Glenn shunt: Clue suggested by agitated saline echo contrast. Saudi J Anaesth 2023;17:77-9
|How to cite this URL:|
Maddali MM, Saxena P, Al Alawi KS, Mohsen A. Cause of profound hypoxemia following a bilateral bidirectional Glenn shunt: Clue suggested by agitated saline echo contrast. Saudi J Anaesth [serial online] 2023 [cited 2023 Feb 1];17:77-9. Available from: https://www.saudija.org/text.asp?2023/17/1/77/364850
| Introduction|| |
Agitated saline (bubble) contrast studies are an important component of contemporary echocardiography. Agitated saline contrast studies play an important role in the demonstration of right to left intracardiac and intrapulmonary shunts and can have major diagnostic implications. This case report highlights the crucial role played by an agitated saline contrast study during intraoperative transesophageal echocardiography that helped in the identification of the cause of profound hypoxemia in a child that underwent a bilateral bidirectional Glenn shunt. Institutional ethical committee approval [SRC#CR10/2022] and informed consent from the parents of the infant were obtained to publish this case report.
| Case Report|| |
A 4-month-old girl [weight: 6 kg; height: 60 cm] with an arterial oxygen saturation of 65% on high flow oxygen supplementation presented for an emergency bilateral bidirectional Glenn shunt following a failed attempt at patent ductus arteriosus stent dilation. The baby was born cyanosed. An immediate transthoracic echocardiography revealed a situs solitus levocardia, atrioventricular concordance, bilateral superior vena cava with a bridging vein, restrictive atrial septal defect, double outlet right ventricle, hypoplastic left ventricle and mitral valve, inlet type ventricular septal defect, pulmonary atresia, and a patent ductus arteriosus. Deployment of a 4 mm drug-eluting stent in the ductus arteriosus with simultaneous atrial balloon septostomy was done as an emergency procedure [Figure 1]. The child was discharged home with a room air arterial oxygen saturation of about 80%. During the current admission, the child was brought to the hospital with a chest infection and was found to have severe arterial oxygen desaturation [below 60%] on room air not responding to supplemental oxygen insufflation. After 3 days of conservative management with antibiotics and oxygen supplementation, an urgent dilation of the ductus arteriosus stent was attempted as transthoracic echocardiography suggested the narrowing of the stent in the ductus arteriosus. The stent dilation failed to improve the arterial oxygen saturation and as the measured pulmonary artery pressures were 15 mm Hg, a bilateral bidirectional Glenn shunt was contemplated to augment pulmonary blood flow. After separation from cardiopulmonary bypass following the creation of the bilateral bidirectional Glenn shunt, the arterial oxygen saturations were persistently low [in the range of 55–60%]. The arterial blood pressure was 100/60 mm Hg, and right and left superior vena cava pressures were 27 mm Hg with 0.5 mcg/kg/min milrinone infusion. A 13 cm long central venous catheter in the right femoral vein displayed a pressure of 17 mm Hg suggesting reduced ventricular function. Increasing the inspired oxygen concentration to 1.0 and administration of 20 ppm nitric oxide did not improve the arterial oxygen saturation beyond 65%. The arterial desaturation was attributed to the preoperative lung infection and reduced myocardial function. It was decided to close the sternotomy and observe the child in the operating room itself. A modified left suprasternal two-dimensional (2-D) transthoracic echocardiography view with color Doppler demonstrated a laminar blood flow across the left Glenn shunt [Figure 2]a and [Figure 2]b. The ventricular contractility was good and there was no regurgitation of the atrioventricular valves. An agitated saline injection into the left internal jugular vein showed the rapid appearance of the saline contrast in the atrium by transesophageal echocardiography [Figure 2]c and [Figure 2]d, [Videoclip 1]. An immediate cardiac catheterization in the hybrid operating room was done to identify the reason for the rapid appearance of the agitated saline echo contrast in the cardiac chambers. Angiographic contrast injection identified an azygos vein communicating with inferior vena cava causing the rapid appearance of the saline contrast in the chambers of the heart mimicking pulmonary arteriovenous malformations in the presence of an obstructed right Glenn shunt [Figure 3].
|Figure 1: Image of the stent deployed in the ductus arteriosus by interventional cardiac catheterization|
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|Figure 2: (a-d) A modified left suprasternal 2-D transthoracic echocardiography view (a) with color Doppler (b) showing a laminar flow through the left vena cava. A mid-esophageal 4-chamber transesophageal echocardiography view showing the chambers of the heart before (c) and after (d) agitated saline injection into the left internal jugular vein|
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|Figure 3: Venous angiography showing the underlying pathology for the profound hypoxemia and the cause for the rapid appearance of the agitated saline in the atrium|
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Cardiopulmonary bypass was reinstituted and the right Glenn shunt was reconstructed. The azygos vein was occluded. Subsequent agitated saline injection into the left jugular vein catheter displayed no saline contrast in the cardiac chambers suggesting that the azygous vein was the cause of the earlier echocardiography findings [Videoclip 2]. The patient was separated from cardiopulmonary bypass with stable hemodynamic parameters. The child's trachea was extubated after 6 h of mechanical ventilation.
| Discussion|| |
Intraoperative transesophageal echocardiography displayed a rapid appearance of saline particles in the cardiac chambers following agitated saline injection, into the jugular vein. The saline particles appeared within three cardiac cycles in the left heart suggesting the presence of pulmonary arteriovenous malformations. However, the clinical picture was not in agreement and a venous angiography revealed the underlying pathology. Agitated saline contrast study to a certain extent helped raise doubt and guide the diagnostic process.
Pulmonary arteriovenous malformations can occur in patients undergoing caval-pulmonary shunts and can remain undetected. They may cause persistent hypoxemia. Agitated saline injection during transthoracic/transesophageal echocardiography into the venous system with immediate appearance of the agitated saline in the left heart within three cardiac cycles is helpful in the diagnosis of these pulmonary arteriovenous malformations.
In patients who have undergone a bilateral bidirectional cavo-pulmonary anastomosis, there may be multiple pulmonary arteriovenous malformations, and cardiac catheterization helps in identifying the extent of the malformations.
In the current patient, the initial explanation for the post-procedure hypoxemia was the preoperative pulmonary dysfunction due to infection. The agitated saline echo contrast study raised the suspicion of pulmonary arteriovenous malformations. However, the predicament was if the hypoxemia was due to pulmonary arteriovenous malformations, why were the bilateral jugular venous pressures elevated? It was observed that the inferior vena cava pressure was elevated [17 mm Hg] and as it was uninterrupted, this suggested an elevated common atrial pressure. It was assumed that the elevated common atrial pressure due to a compromised ventricular function may be responsible for the elevated Glenn pressures. To address this dilemma, an immediate venous angiography was done that revealed the underlying problem.
The agitated saline contrast study was helpful to a certain extent in raising the doubt and guiding the diagnostic process that led to the immediate reoperation and a successful patient outcome.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has provided consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]