Glenn Shunt

Glenn Shunt

Cite this article as:
Anders, M. Glenn Shunt, Don't Forget the Bubbles, 2013. Available at:
http://doi.org/10.31440/DFTB.3604

Definition: transection of the SVC, which is anastomosed to the right pulmonary artery (RPA). Hemi-fontan: confluence of SVC and RA anastomosed to RPA. Redirection of IVC and coronary sinus via baffle through ASD into LA.


Physiology:

  • Aim for SpO2 75-85%
  • LV preload and cardiac output are maintained by IVC flow
  • Pulmonary blood flow maintained is by SVC flow. (Transpulmonary gradient: SVC (CVP) – LAP)

Preoperative preparation:

ECG, CXR, CUS, FBE, clotting, UEC, PRBC (4), FFP (2), platelets (2), cryoprecipitate (2).


Postoperative management:

  • Commence heparin 10U/kg/hr once there is no major bleeding; change to aspirin (5 mg/kg) orally once enteral feeds tolerated
  • Respiratory: SpO2 75-85%. May need some time to settle the pulmonary blood flow and achieve stable saturations.Try to extubate early if feasible
  • Inotropes: usually not required, if so milrinone to decrease PVR and SVR and improve ventricular dysfunction
  • Fluid restriction: 2ml/kg/hr for the first day, feed early
  • Haemostasis
  • Remove all central lines as soon as possible

Specific problems:

  • Persistent hypoxaemia (SpO2 <70%) may indicate a mechanical obstruction of SVC – RPA (> 2-5 mmHg) anastomosis
  • Elevated PVR leading to hypoxaemia (increased transpulmonary gradient >18 mmHg). If intubated, aim for extubation if feasible; try higher FiO2, normal pH; trial of NO. Do not hyperventilate as this will cause decreased cerebral blood flow! Evacuate any pleural effusion early
  • Increased LAP pressure (>12 mmHg): commence milrinone, check ECHO for ventricular function and AV valve regurgitation
  • Consistent pulmonary venous congestion: check for anomalous connection SVC to LA
  • Risk of air embolism due to right to left shunt (from IVC territory)

Outcome:

  • Good palliation in younger children, but as the child grows the IVC blood flow increases leading to desaturations (Fontan circulation)
  • 1 ½ ventricular repair preferable: forward-flow/pulsatile flow into the PA in selected patients to prevent pulmonary AV fistulas

References:

[1] Critical Heart Disease in Infants and Children; 2nd ed, Nichols et al: Tricuspid Atresia

[2] Ann Thorac Surg. 1999 Sep;68(3):976-81; discussion 982: Mavroudis et al: Bidirectional Glenn shunt in association with congenital heart repairs: the 1(1/2) ventricular repair

[3] Arch Surg 1963;86:101: Shumacker: Discussion of Reed WA, Kittle CF, Heilbrunn A: Superior vena cava-pulmonary artery anastomosis

[4] Acta Med Scand 1956;154: 151-61.Robicsek et al: A new method for the treatment of congenital heart disease associated with impaired pulmonary circulation

[5] Pediatr Crit Care Med. 2011 Vol. 12, No.1: 39-45: Cholette et al: Children with single-ventricle physiology do not benefit from higher haemoglobin levels post cavopulmonary connection: Results of a prospective, randomized, controlled trial of a restrictive versus liberal red-cell transfusion strategy


 All Marc’s PICU cardiology FOAM can be found on PICU Doctor and can be downloaded as a handy app for free on iPhone or AndroidA list of contributors can be seen here.

If you enjoyed this post, why not check out our live conference on 26th August. Find out more about DFTB: Live + Connected

About Marc Anders

AvatarMarc Anders is a paediatric intensivist.

Avatar
Author: Marc Anders Marc Anders is a paediatric intensivist.

Leave a Reply