Laparoscopic Surgery in an Adult with a Fontan Circulation
A 24-year-old man with hypoplastic left heart syndrome palliated to an extracardiac Fontan conduit presents with acute calculous cholecystitis and needs laparoscopic cholecystectomy. Baseline SpO2 is 92% on room air, BP 102/62 mmHg, and HR 72 in sinus rhythm. Systemic ventricular EF is 45%, Fontan pressure 15 mmHg, there is mild ascites and a serum albumin of 3.1 g/dL from protein-losing enteropathy, and he takes furosemide and warfarin for a prior conduit thrombus. The INR is 1.3 after five days of holding. The surgeon wants to proceed tonight. He has had clear liquids only for 14 hours and appears mildly hypovolemic and anxious.
1. State the physiologic determinants of cardiac output in this patient and the biggest threats during induction and pneumoperitoneum, then outline your induction and ventilation strategy.
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Physiology. There is no subpulmonary ventricle. Pulmonary blood flow is driven by the gradient between systemic venous pressure and pulmonary venous pressure, and cardiac output equals pulmonary blood flow. That makes the circulation preload-dependent, dependent on low pulmonary vascular resistance, dependent on sinus rhythm and on a low mean intrathoracic pressure, and intolerant of anything that raises the pressure in the chest or the pulmonary vasculature. Systemic venous pressure is what fills the conduit, so a fall in venous return or in systemic vascular tone reduces the gradient.
Threats. Induction agents cause vasodilation and a drop in systemic venous pressure; positive pressure ventilation and pneumoperitoneum raise intrathoracic pressure and reduce venous return; hypoxemia, hypercarbia, acidosis, hypothermia, and high airway pressures raise pulmonary vascular resistance; and dehydration from fasting worsens all of it.
Plan.
- Give a fluid bolus (10 mL/kg) before induction; the patient's history of fasting and his anxious appearance already suggest hypovolemia.
- Induce slowly and incrementally with an agent that preserves tone - etomidate, or ketamine with a small dose of propofol. Aim for a controlled, unhurried sequence, and have phenylephrine and vasopressin drawn up and running before you lose the airway.
- Ventilate with modest tidal volumes (6–8 mL/kg), a normal rate, and low PEEP (5 cmH2O), targeting a PaCO2 of about 40 mmHg and avoiding hypercarbia and hypoxia.
- Ask the surgeon to keep insufflation pressure at or below 10–12 mmHg and to use the lowest pressure that provides exposure; if the patient becomes unstable, ask them to desufflate immediately.
2. What monitoring and access will you establish, and do you proceed tonight with an INR of 1.3? Justify the timing decision.
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Monitoring and access. An arterial line before induction is essential: the blood pressure is the only real-time indicator of systemic vascular tone and, indirectly, of the transpulmonary gradient. Secure two large-bore peripheral IVs. A central line is reasonable but not mandatory; it provides a reliable route for vasoactive infusions and a central venous pressure trend, and - importantly - the catheter should be flushed carefully, because any patient with a Fontan circulation who has a fenestration has a right-to-left shunt and is at risk of paradoxical air embolism from any line. Use an air-eliminating filter on all infusions. Standard monitors, temperature monitoring, and a Foley catheter to follow urine output.
Timing. Proceed. An INR of 1.3 after five days of warfarin is not a prohibitive bleeding risk for a laparoscopic cholecystectomy, and holding longer would be more dangerous than operating. The patient has acute cholecystitis, which produces an inflammatory and procoagulant state, and a Fontan conduit with low flow, a prior thrombus, dehydration, and protein-losing enteropathy is one of the highest-risk settings for conduit thrombosis. A brief delay to give vitamin K or FFP would not lower the risk of thrombosis, but it would increase the risk of bleeding and would delay source control of an infection that is driving the procoagulant state.
So the plan is: proceed tonight with the congenital cardiology team aware, correct volume status, avoid hypotension, and restart anticoagulation early rather than waiting for a 'safe' window that never comes.
3. Describe your immediate postoperative disposition and the plan for hemodynamics, fluid management, and anticoagulation over the next 48 hours.
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Disposition. A cardiac-capable intensive care unit, not a general surgical floor. This patient has a single ventricle, protein-losing enteropathy, and a recent infection, and is at risk for low cardiac output, conduit thrombosis, and bleeding. Extubate as soon as it is safe: spontaneous negative-pressure ventilation lowers mean intrathoracic pressure and improves pulmonary blood flow, so the same physiology that made induction difficult makes early extubation desirable.
Hemodynamics. Keep the systemic venous pressure adequate - a CVP around his baseline Fontan pressure of 15, and do not chase a 'normal' CVP of 5. Use vasopressin or norepinephrine for tone; avoid pure vasodilators and avoid deep sedation that drops venous return. Watch for arrhythmia: the Fontan patient tolerates loss of sinus rhythm poorly, and any new atrial arrhythmia should be treated promptly.
Fluids and end-organ function. Replace insensible losses and blood loss; he is likely to need volume and albumin. Follow urine output, lactate, liver function, and daily weight, and remember that protein-losing enteropathy means his albumin and oncotic pressure are low and his enteric protein losses will increase with any venous hypertension.
Anticoagulation. Restart warfarin within 24–48 hours once he is taking enteral medication and hemostasis is secure, and bridge with prophylactic or low-dose therapeutic heparin in the interim, decided with the congenital cardiologist and taking into account surgical bleeding. Avoid NSAIDs. Add mechanical prophylaxis, and arrange early ambulation.