Christopher.Deeble: added info

2024-05-04T19:24:25Z

added info

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	~~Commonly~~ as the final staged ~~surgical repair~~ of ~~patients with single ventricles~~.		Estimated around 70,000 patients worldwide with Fontan circulation. Performed in patients where biventricular repair not possible; conditions such as tricuspid atresia, pulmonary atresia with intact ventricular septum, double inlet left ventricle, hypoplastic left heart syndrome, double outlet right ventricle, and complete atrioventricular septal defects. Fontan is usually the final of 3 stages of palliative surgery (first being Norwood, second being Glenn); staged approach to allow the body to adapt. Patients tend to demonstrate gradual decline over time.

			Fontan circulation dependent on systemic venous pressure, PVR, AV valve function, cardiac rhythm, and ventricular function. Driving force of blood through pulmonary circuit is dependent on the different between the central venous pressure and the atrial pressure (passive process). CVP is mainly determined by intravascular volume, thus hypovolemia is poorly tolerated. Also important to maintain sinus rhythm and competent AV valve for optimal atrial emptying and ventricular filling. Additionally avoid agents that decrease myocardial contractility, as well avoid increases in PVR.

	== Anesthetic implications<!-- Briefly summarize the anesthetic implications of this comorbidity. --> ==		== Anesthetic implications<!-- Briefly summarize the anesthetic implications of this comorbidity. --> ==

	=== Preoperative optimization<!-- Describe how this comorbidity may influence preoperative evaluation and optimization of patients. --> ===		=== Preoperative optimization<!-- Describe how this comorbidity may influence preoperative evaluation and optimization of patients. --> ===
			Detailed history and physical examination

			Baseline labs, ECG, Echo.

	=== Intraoperative management<!-- Describe how this comorbidity may influence intraoperative management. --> ===		=== Intraoperative management<!-- Describe how this comorbidity may influence intraoperative management. --> ===
			If undergoing major surgery with fluid shifts, monitor with arterial line and CVP. Young patient with well compensated Fontan physiology with CVP (mPAP) of 12 mmHg, and atrial pressure of 5 mmHg (transpulmonary pressure gradient of 7 mmHg).

			Avoid hypotension from anesthetic agents (such as high concentration volatiles, or induction agents that drop SVR). Avoid increased in PVR (such as hypercarbia, acidosis, increased intrathoracic pressure, inadequate analgesia/anesthesia)

			Spontaneous ventilation may be beneficial for short procedures if able to avoid hypercarbia. If needing invasive ventilation, need to avoid increased in intrathoracic pressure (which would decrease venous return, and in turn reduce pulmonary blood flow); thus low respiratory rates, short inspiratory times, low PEEP, tidal volumes 5-6 mL/kg. Plan for early extubation.

	=== Postoperative management<!-- Describe how this comorbidity may influence postoperative management. --> ===		=== Postoperative management<!-- Describe how this comorbidity may influence postoperative management. --> ===
			Monitor oxygen saturation, volume status. Address anticoagulation needs. Adequate pain management to facilitate normal breathing patterns.

	== Related surgical procedures<!-- List and briefly describe any procedures which may be performed specifically to treat this comorbidity or its sequelae. If none, this section may be removed. --> ==		== Related surgical procedures<!-- List and briefly describe any procedures which may be performed specifically to treat this comorbidity or its sequelae. If none, this section may be removed. --> ==
	Norwood		Norwood (stage 1)

	Glenn		Glenn (stage 2)

			Heart transplant (as treatment for failing Fontans)

	== Pathophysiology<!-- Describe the pathophysiology of this comorbidity. Add subsections as needed. --> ==		== Pathophysiology<!-- Describe the pathophysiology of this comorbidity. Add subsections as needed. --> ==
	~~Single ventricle physiology~~, ~~with passive filling of pulmonary arteries.~~		Abnormal cardiorespiratory response to exercise: blunted heart rate response, limited ability to increase stroke volume (impaired ventricular function and difficulty increasing preload)

	~~Failing Fontan~~ physiology ~~commonly~~ with following ~~signs~~ and ~~symptoms:~~		Restrictive respiratory physiology in up to 89% of patients, due to both extrinsic and intrinsic causes; can also experience recurrent pneumonias, pleural effusions, pulmonary embolisms, and in rare cases plastic bronchitis.

			45% of patients with atrial arrhythmias in 10 years following surgery, related to multiple suture lines near sinus node, atrial enlargement, and elevated atrial pressure.

			Left to right shunts may be present due to aorto-pulmonary collaterals, or incomplete occlusion of prior artificial shunts; may result in increases in PVR and volume overload of ventricle

			Protein losing enteropathy in 13% of patients in a 10 year follow up after surgery. Manifests as edema, ascites, malabsorption of fat, hypercoagulopathy, hypocalcemia, hypomagnesemia, immunodeficiency

			In 10-year follow-up studies, about 30% of patients with thromboembolic events. Patients usually with anticoagulation or antiplatelet agents.

			Fontan associated liver disease causing congestion, fibrosis, and cirrhosis; usually progressive.

	== Signs and symptoms<!-- Describe the signs and symptoms of this comorbidity. --> ==		== Signs and symptoms<!-- Describe the signs and symptoms of this comorbidity. --> ==

	== Diagnosis<!-- Describe how this comorbidity is diagnosed. --> ==		== Diagnosis<!-- Describe how this comorbidity is diagnosed. --> ==
			Assess Fontan function with Echo, CT and MRI.

	== Treatment<!-- Summarize the treatment of this comorbidity. Add subsections as needed. --> ==		== Treatment<!-- Summarize the treatment of this comorbidity. Add subsections as needed. --> ==
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	=== Surgery<!-- Describe surgical procedures used to treat this comorbidity. --> ===		=== Surgery<!-- Describe surgical procedures used to treat this comorbidity. --> ===
	If Fontan ~~fails~~, ~~patient may be considered for~~ a ~~heart transplant~~.		Fontan final stage usually performed around 1-5 years of age. Blood from IVC is directed to pulmonary circuit via extracardiac conduit (usual), or intra-atrial baffle. Some patients require a small fenestration between right atrium and conduit to limit caval pressures, as well as increase preload to ventricle.

	=== Prognosis<!-- Describe the prognosis of this comorbidity --> ===		=== Prognosis<!-- Describe the prognosis of this comorbidity --> ===
			After Fontan surgery, 30-year survival of >80%. After diagnosis of PLE, 60% 5-year and 20% 10-year survival.

	== Epidemiology<!-- Describe the epidemiology of this comorbidity --> ==		== Epidemiology<!-- Describe the epidemiology of this comorbidity --> ==

	== References ==		== References ==
			Lei SY. FONTAN PHYSIOLOGY. In: Houck PJ, Haché M, Sun LS. eds. ''Handbook of Pediatric Anesthesia''. McGraw Hill; 2015. Accessed June 04, 2023. <nowiki>https://accesspediatrics.mhmedical.com/content.aspx?bookid=1189&sectionid=70364339</nowiki>

			McNamara JR, McMahon A, Griffin M. Perioperative Management of the Fontan Patient for Cardiac and Noncardiac Surgery. J Cardiothorac Vasc Anesth. 2022 Jan;36(1):275-285. doi: 10.1053/j.jvca.2021.04.021. Epub 2021 Apr 20. PMID: 34023201.

			Sandeep Nayak, MBBS MD FRCA , P.D. Booker, MBBS MD FRCA, The Fontan circulation, ''Continuing Education in Anaesthesia Critical Care & Pain'', Volume 8, Issue 1, February 2008, Pages 26–30, <nowiki>https://doi.org/10.1093/bjaceaccp/mkm047</nowiki>
	[[Category:Comorbidities]]		[[Category:Comorbidities]]

Christopher.Deeble: Created page with "{{Infobox comorbidity | other_names = | anesthetic_relevance = | specialty = | signs_symptoms = | diagnosis = | treatment = | image = | caption = }} Commonly as the final staged surgical repair of patients with single ventricles. == Anesthetic implications == === Preoperative optimization

Fontan - Revision history

Christopher.Deeble: added info