Congenital Cardiac Anesthesia Society
A Section of the the Society for Pediatric Anesthesia

{“questions”:{“unq3h”:{“id”:”unq3h”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Nicholas Houska, DO – University of Colorado, Children\u2019s Hospital Colorado \r\n\r\nA 1-week-old, 3.6 kg neonate is admitted to the cardiac intensive care unit with decreased responsiveness, poor urine output and diminished femoral pulses. A transthoracic echocardiogram reveals coarctation of the aorta.\r\n \r\nWhat is the MOST likely coexisting congenital heart defect in this patient?”,”desc”:”EXPLANATION \r\nBicuspid aortic valve (BAV) is the most common congenital heart defect with a prevalence of 1-2%. Coarctation of the aorta (CoA) occurs in three out of every 10,000 live births but is more common when occurring in conjunction with other congenital heart defects. BAV and CoA have a male to female predominance of 2:1to 4:1. In addition, both are associated with Turner syndrome. While approximately 7% of patients with a BAV will also have a coarctation of the aorta, upwards of 85 % of patients with CoA will have concurrent bicuspid aortic valve. The frequent association of CoA and BAV together suggest an underlying generalized arteriopathy. This may place patients at risk for future complications and the need for further catheter and surgical based interventions. Bicuspid aortic valve is the most common cause of aortic valve stenosis and aortic valve replacement in patients under 60 years of age. \r\n\r\nCoarctation of the aorta can lead to hypertension, which often persists even after complete repair. Approximately 10% of patients with aortic coarctation also have intracranial aneurysms, increasing the risk of cerebrovascular accidents. Other complications include congestive heart failure, endocarditis, and aortic dissection and rupture secondary to dilatation of the aorta. The rate of recurrence of aortic coarctation requiring reintervention after surgical repair is reported to be 5-15%. Due to the long-term complications of BAV and CoA, regular follow-up with a cardiologist is recommended. \r\n\r\n\r\n\r\n \r\nREFERENCES \r\nSinning C, Zengin E, Kozlik-Feldmann R, et al. Bicuspid aortic valve and aortic coarctation in congenital heart disease-important aspects for treatment with focus on aortic vasculopathy. Cardiovasc Diagn Ther<\/em>. 2018;8(6):780-788. \r\n\r\nWarnes CA. Bicuspid aortic valve and coarctation: two villains part of a diffuse problem. Heart <\/em>.2003;89(9):965-966. \r\n\r\nTorok RD, Campbell MJ, Fleming GA, Hill KD. Coarctation of the aorta: Management from infancy to adulthood. World J Cardiol<\/em>. 2015;7(11):765-775. \r\n\r\nBacha E, Hijazi ZM. (2023) Management of coarctation of the aorta. UpToDate<\/em>. Retrieved July 4, 2023, from: https:\/\/www.uptodate.com\/contents\/management-of-coarctation-of-the-aorta\r\n”,”hint”:””,”answers”:{“w39rf”:{“id”:”w39rf”,”image”:””,”imageId”:””,”title”:”A.\tAtrial Septal Defect”},”wnj42″:{“id”:”wnj42″,”image”:””,”imageId”:””,”title”:”B.\tBicuspid Aortic Valve”,”isCorrect”:”1″},”q1x1x”:{“id”:”q1x1x”,”image”:””,”imageId”:””,”title”:”C.\tVentricular Septal Defect”}}}}}

{“questions”:{“y4n0w”:{“id”:”y4n0w”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Nicholas Houska, DO – University of Colorado. Children\u2019s Hospital Colorado \r\n\r\nA 12-year-old female with a history of repaired Tetralogy of Fallot during infancy presents for surgical pulmonary valve replacement. Due to coronary anatomy, transcatheter pulmonary valve implantation is not an option. Which type of surgical pulmonary valve replacement is associated with the HIGHEST incidence of infective endocarditis?”,”desc”:”EXPLANATION \r\n\r\nReconstruction of the right ventricular outflow tract with implantation of an extracardiac pulmonary-valved conduit may be necessary in patients with both acquired and congenital heart disease. Alternatively, the pulmonary valve may be replaced with a bioprosthetic or mechanical valve. Conduits used for this purpose include cryopreserved pulmonic or aortic homografts, Contegra conduits, and transcatheter pulmonary valves (Melody and Edwards SAPIEN). Homograft conduits have been used for the last 50-60 years, while Contegra conduit use began in the last 20-25 years. Contegra conduits are made of bovine jugular vein with a trileaflet venous valve. The Melody and Edwards SAPIEN valves are two types of percutaneously implanted pulmonary valves. The Melody valve is composed of bovine jugular vein with a trileaflet venous valve sutured into an expandable platinum stent. The Edwards SAPIEN valve is comprised of bovine pericardium that is shaped into a trileaflet valve and mounted onto an expandable cobalt-chromium frame. One large nationwide registry-based study that included all patients with at least one pulmonary valve replacement prior to 2018 by Stammnitz et al demonstrated that pulmonary valve replacement (PVR) with a bovine jugular vein valve (Contegra conduit or Melody valve) has the highest risk of infective endocarditis (IE) irrespective of mode of deployment, either surgical or percutaneous. In this study, the overall incidence of IE was 4.8% after a median follow up of 10 years per patient. Patients with a Contegra conduit had an incidence of IE of 5.4% while those with a homograft had an incidence of 1.3%. There was a 0% incidence of IE in patients with a mechanical valve or Edwards SAPIEN valve. The risk for IE was higher for surgically implanted Contegra grafts (HR, 5.62; 95% CI, 2.42\u201313.07; P<0.001) and transcatheter Melody Valves (HR, 7.81; 95% CI, 3.20\u201319.05; P<0.001) compared to homografts. The median time interval from PVR to infective endocarditis was 3 and 5 years for Contegra conduit and Melody valves respectively. The increased risk of IE with Contegra conduits and transcatheter Melody valves as compared to homograft conduits has been demonstrated in smaller studies as well. \r\n\r\n \r\nREFERENCES \r\nStammnitz C, Huscher D, Bauer UMM, et al. Nationwide registry\u2010based analysis of infective endocarditis risk after pulmonary valve replacement. JAHA<\/em>. 2022;11(5): e022231. \r\n\r\nHaas NA, Bach S, Vcasna R, et al. The risk of bacterial endocarditis after percutaneous and surgical biological pulmonary valve implantation. Int J cardiol<\/em>. 2018; 268:55-60. \r\n\r\nGr\u00f6ning M, Tahri NB, S\u00f8ndergaard L, Helvind M, Ersb\u00f8ll MK, Andersen H\u00d8. Infective endocarditis in right ventricular outflow tract conduits: a register-based comparison of homografts, Contegra grafts and Melody transcatheter valves. Eur J Cardiothorac Surg <\/em>.2019; 56(1):87-93.\r\n”,”hint”:””,”answers”:{“ppo92”:{“id”:”ppo92″,”image”:””,”imageId”:””,”title”:”A.\tHomograft conduit”},”x61h5″:{“id”:”x61h5″,”image”:””,”imageId”:””,”title”:”B.\tMechanical valve”},”6b9lm”:{“id”:”6b9lm”,”image”:””,”imageId”:””,”title”:”C.\tValved bovine jugular vein conduit (Contegra)”,”isCorrect”:”1″}}}}}

{“questions”:{“silxl”:{“id”:”silxl”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Melissa Colizza, MD – CHU Sainte-Justine, Montreal, Quebec \r\n\r\nA 4-year-old male with a history of hypoplastic left heart syndrome (HLHS) and previous bidirectional Glenn with extensive bilateral pulmonary artery reconstruction undergoes a fenestrated Fontan procedure. On post-operative day one, the blood pressure decreases gradually to 64\/32 from 92\/45 despite increased vasoactive support with epinephrine and vasopressin, and the lactate increases from 1.4 to 4.2 The Fontan pressure is 20 mmHg with a common atrial pressure of 7 mm Hg and an oxygen saturation of 94% in room air. What is the MOST likely cause of the hypotension?”,”desc”:”EXPLANATION \r\nEarly Fontan failure consists of low cardiac output with high Fontan pressure that remains refractory to medical therapy. In recent years, the risk of early Fontan failure in experienced centers varies from 2-6%. It is usually caused by residual defects along the Fontan pathway such as atrioventricular valve (AVV) regurgitation, inadequate pulmonary artery (PA) size or dysrhythmias. Other factors that are known to be associated with a high risk of Fontan failure include heterotaxy, dominant-right ventricle (RV) morphology, common AV valve, increased pre-operative pulmonary artery pressure (PAP), increased post-operative Fontan pressure, elevated left ventricular end-diastolic pressure (LVEDP), and prolonged cardiopulmonary bypass (CPB) and cross-clamp times. \r\n\tIn 1989, the concept of fenestration was introduced as a technique to preserve cardiac output, albeit at the expense of systemic oxygen desaturation, and to minimize the complications associated with high systemic venous pressures such as, pleural effusions, ascites, and lymphatic dysfunction. The fenestration has allowed for expanded Fontan candidacy, including patients previously deemed high-risk. Early reports demonstrated decreased length of hospital stay, leading to the widespread use of a Fontan fenestration in the 1990s. Its popularity waned in the face of undesirable long-term complications, including lower resting systemic oxygen saturation resulting in diminished exercise tolerance and higher risk for systemic thromboembolism. Despite being widely used, there is still much debate about the risks and benefits of fenestration. Two meta-analyses by Bouhout et al. and Li et al. have come to different conclusions. Bouhout et al. reported that the main benefits of a fenestration were lower PAP and decreased chest tube drainage. Li et al. described a lower burden of dysrhythmias. Both studies concluded that there was no significant difference in early mortality, need for Fontan takedown, length of hospital stay, or incidence of stroke or thrombosis. A retrospective study by Daley et al. demonstrated that patients with a fenestration had significantly lower survival, lower freedom from failing Fontan physiology and lower thromboembolic disease. However, the groups were overall unmatched; fenestrated patients had a higher incidence of HLHS, RV dominance, lateral tunnel Fontan, significant AVV regurgitation or AVV surgery, need for PA plasty, and higher mean PAP. These findings illustrate the challenge to objectively determine the benefits of Fontan fenestration since it is typically reserved for patients at higher risk for Fontan failure, which creates selection bias across studies. \r\n\r\n\r\nFontan failure can be categorized as circulatory failure or mechanical pump failure. Circulatory failure refers to the inability to maintain adequate pulmonary blood flow through the pulmonary vascular bed with an acceptable Fontan pressure. The pulmonary vascular bed is the most critical \u201cbottleneck\u201d, and successful Fontan circulation requires low pulmonary vascular resistance (PVR) and adequately sized pulmonary arteries. Mechanical pump failure relates to inability of the heart to meet systemic oxygen demand and may be secondary to systolic or diastolic dysfunction, dysrrhythmia, obstruction along the systemic vascular pathway or AVV regurgitation. Isolated systolic dysfunction remains fairly uncommon in the immediate post-operative period and should prompt investigation into an acute cause. It rarely causes profound cardiogenic shock unless the cardiac function is so poor that high atrial pressures prevent blood flow through the fenestration or through the pulmonary circulation. The child in the question has low cardiac output, low common atrial pressure and high Fontan pressures which would be consistent with circulatory failure. In the case of mechanical pump failure due to severe AVV regurgitation or systolic dysfunction, the common atrial pressure would likely be higher than 7 mm Hg. However, if the common atrial pressure remains lower than the Fontan pressure, shunting of desaturated blood through a patent fenestration is expected resulting in a systemic oxygen saturation ranging from of 70-80%. Shunting of desaturated blood is also expected in patients with a fenestrated Fontan and high pulmonary artery pressures secondary to hypoplastic pulmonary arteries or high pulmonary vascular resistance.\r\n\r\n\r\n\tPost-cardiopulmonary bypass vasoplegia is a type of distributive shock typically occurring within the first 24 hours post-operatively. It is characterized by hypotension, high cardiac output, and low systemic vascular resistance that is relatively resistant to vasopressors and fluids. Vasoplegia tends to occur in cases of long CPB\/cross-clamp times, and the pre-operative use of systemic vasodilators. It classically presents with hypotension requiring treatment with vasoactive medications in the absence of low mixed venous saturation or high lactate. Therefore, it is less likely in this patient. \r\n\r\nIn the above case, our patient is a high-risk Fontan due to the presence of a high fixed resistance to pulmonary blood flow secondary to hypoplastic pulmonary arteries (note the history of bilateral pulmonary artery reconstruction with likely residual pulmonary hypoplasia). The new finding of high Fontan pressures, low common atrial pressure, and high systemic saturation with evidence of a low cardiac output state points to an occluded fenestration. In this scenario, there is inadequate pulmonary blood flow through the lungs resulting in low cardiac output, and an absence of blood flow through the fenestration resulting in high systemic oxygen saturation given absent mixing of pulmonary venous return and systemic venous return in the common atrium. Although re-opening a fenestration is feasible in the cardiac catheterization lab, this may be associated with a high risk of systemic thromboembolism as the most likely cause of occlusion in the early post-operative period is a thrombus. Since most fenestrations are only 4 mm in diameter, reopening it may only have marginal benefits on such tenuous hemodynamics and further diagnostic evaluation, such as computed tomography with angiography or cardiac catheterization, may be needed. In the worst-case scenario, the Fontan may have to be taken down. \r\n\r\n\r\n\r\n \r\nREFERENCES \r\n\r\nGewillig M, Brown SC. The Fontan circulation after 45 years: update in physiology. Heart <\/em>.2016;102(14):1081-1086. doi: 10.1136\/heartjnl-2015-307467\r\n\r\nDesphpande SR, Bearl DW, Eghtesady P, et al. Clinical approach to vasoplegia in the transplant patient from the Pediatric Heart Transplant Society. Pediatr Transplant<\/em>. 2022; 26(8):e14392. doi: 10.1111\/petr.14392\r\n\r\nRochelson E, Richmond ME, LaPar DJ, Torres A, Anderson BR. Identification of Risk Factors for Early Fontan Failure. Semin Thorac Cardiovasc Surg.<\/em> 2020; 32(3):522-528. doi: 10.1053\/j.semtcvs.2020.02.018\r\n\r\nBouhout I, Ben-Ali W, Khalaf D, Raboisson MJ, Poirier N. Effect of Fenestration on Fontan Procedure Outcomes: A Meta-Analysis and Review. Ann Thorac Surg<\/em>. 2020; 109(5):1467-1474. doi: 10.1016\/j.athoracsur.2019.12.020\r\n\r\n\r\nLi D, Li M, Zhou X, An Q. Comparison of the fenestrated and non-fenestrated Fontan procedures: A meta-analysis. Medicine (Baltimore)<\/em>. 2019; 98(29):e16554. doi: 10.1097\/MD.0000000000016554 \r\n\r\n\r\nDaley M, Buratto E, King G, et al. Impact of Fontan Fenestration on Long-Term Outcomes: A Propensity Score-Matched Analysis. J Am Heart Assoc<\/em>. 2022;11(11):e026087. doi: 10.1161\/JAHA.122.026087\r\n\r\n”,”hint”:””,”answers”:{“cy049”:{“id”:”cy049″,”image”:””,”imageId”:””,”title”:”A. Obstructed fenestration”,”isCorrect”:”1″},”lhs5o”:{“id”:”lhs5o”,”image”:””,”imageId”:””,”title”:”B. Vasoplegia”},”zh0xi”:{“id”:”zh0xi”,”image”:””,”imageId”:””,”title”:”C. Severe atrioventricular valve regurgitation\r\n\r\n”}}}}}

{“questions”:{“8uhfq”:{“id”:”8uhfq”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Sana Ullah, MB ChB, FRCA – Children\u2019s Medical Center, Dallas \r\n\r\nWhat is the MOST COMMON syndrome associated with pulmonary arteriovenous malformations?”,”desc”:”EXPLANATION \r\nPulmonary arteriovenous malformations (AVMs) are structurally abnormal blood vessels which form direct communications between the pulmonary arterial and pulmonary venous circulations, producing a right-to-left shunt bypassing the alveolar gas exchange regions and the normal filtering functions of the lungs. The most common cause of pulmonary AVMs is Osler-Weber-Rendu syndrome, which is also known as Hereditary Hemorrhagic Telangiectasia (HHT). Osler-Weber-Rendu is inherited in an autosomal dominant manner and affects approximately 1 in 5,000 to 8,000 people. In addition to AVMs, smaller telangiectatic vessels that are prone to bleeding are frequently found in nasal, mucocutaneous, hepatic, gastrointestinal and cerebral vascular beds. \r\nPulmonary AVMs can also develop after surgical palliation with the bidirectional cavopulmonary shunt and produce significant systemic desaturation. The purported mechanism is due to the lack of a \u201chepatic factor\u201d that bypasses the pulmonary circulation after the bidirectional cavopulmonary shunt. Once the hepatic venous return is redirected back into the pulmonary circulation after Fontan completion, the pulmonary AVMs generally regress over a period of weeks to months. \r\nThe major clinical manifestations of pulmonary AVMs are recurrent bleeding manifesting as hemoptysis or hemothorax, systemic desaturation due to right-to-left shunting, ischemic strokes due to paradoxical thromboembolism, and cerebral abscesses resulting from bacteria in the blood that bypasses the filtering mechanism of the lungs. There is also an increased risk of pregnancy-related deaths in pregnant women with pulmonary AVMs. As a result of pulmonary AVMs, a rare but interesting phenomenon, is platypnea-orthodeoxia, which is best described as systemic desaturation and increased shortness of breath on standing up but improvement on lying flat. This is because most pulmonary AVMs are in the basal regions of the lungs thereby increasing the right-to-left shunt due to increased blood flow on assuming the upright posture. \r\nComputed tomography of the chest is the gold-standard for diagnosis of pulmonary AVMs and offers better resolution than MRI. Contrast echocardiography using agitated saline injected into an arm vein and imaging the left side of the heart can also be used, but it lacks specificity even though it is highly sensitive. Transcatheter embolization is recommended for treatment of all pulmonary AVMs that are amenable to vessel access. \r\nScimitar syndrome is a rare variant of partial anomalous pulmonary venous return of a portion or the entirety of the right lung to the inferior vena cava. The abnormal venous channel forms a characteristic curved shadow on chest x-ray along the right heart border which resembles a sword known as a scimitar. Associated abnormalities include hypoplasia of the right lung, secondary dextroposition of the heart, and pulmonary sequestration of portions of the right. The sequestered lung does not take part in gas exchange and is prone to recurrent bleeding and infection. Management of Scimitar Syndrome is largely determined by the degree of volume overload to the heart and associated cardiac anomalies. Lung segments affected by sequestration may need to be resected. Kartagener\u2019s syndrome is an autosomal recessive disorder characterized by primary ciliary dyskinesis resulting in a triad of situs inversus totalis, chronic sinusitis, and bronchiectasis. Alagille syndrome is an autosomal dominant disorder consisting of bile duct paucity and cholestasis, characteristic triangular facies, widespread vascular anomalies, and congenital heart disease. The congenital heart disease often manifests as peripheral pulmonary arterial stenosis or hypoplasia, pulmonary valve stenosis, and\/or Tetralogy of Fallot. Treatment of pulmonary arterial stenosis often requires a combination of surgical and transcatheter based techniques. Approximately 15% of patients eventually develop liver failure requiring transplantation. Many of these patients harbor a mutation in the JAG1 gene. \r\n\r\n \r\nREFERENCES \r\nShovlin CL. Pulmonary Arteriovenous Malformations. Am J Respir Crit Care Med <\/em> . 2014; 190(11): 1217-1228. \r\nVida VL, Guariento A. A sword threatening the heart: The scimitar syndrome. JCTVS Techniques <\/em>.2020; 1: 75-80.\r\nTretter JT, McElhinney DB. Cardiac, Aortic, and Pulmonary Vascular Involvement in Alagille Syndrome. 2018. In: Kamath B., Loomes K. (eds) Alagille Syndrome. Springer, Cham. https:\/\/doi.org\/10.1007\/978-3-319-94571-2_6\r\n\r\nKamath BM, Spinner NB, Emerick KM, et al. Vascular anomalies in Alagille syndrome: A significant cause of morbidity and mortality. Circulation. <\/em>2004; 109:1354-1358.\r\n\r\n\r\n”,”hint”:””,”answers”:{“e3zth”:{“id”:”e3zth”,”image”:””,”imageId”:””,”title”:”A.\tScimitar syndrome”},”omyi8″:{“id”:”omyi8″,”image”:””,”imageId”:””,”title”:”B.\tOsler-Weber-Rendu syndrome”,”isCorrect”:”1″},”3x7h8″:{“id”:”3x7h8″,”image”:””,”imageId”:””,”title”:”C.\tKartagener\u2019s syndrome”},”48z12″:{“id”:”48z12″,”image”:””,”imageId”:””,”title”:”D.\tAlagille syndrome”}}}}}

{“questions”:{“9erfa”:{“id”:”9erfa”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Melissa Colizza, MD – CHU Sainte-Justine Montreal, Quebec \r\n\r\nA 7-year-old girl with suprasystemic idiopathic pulmonary hypertension is undergoing cardiac catheterization. During the procedure, the blood pressure decreases to 65\/35. Which of the following medications is MOST appropriate to treat the systemic hypotension? “,”desc”:”EXPLANATION \r\nPulmonary hypertension (PH) is one of the most important causes of perioperative mortality and morbidity in the pediatric population. The three most common causes of pulmonary hypertension in the pediatric population are bronchopulmonary dysplasia, congenital heart disease or left-sided heart disease, and idiopathic PH. Patients with PH often come to the cardiac catheterization lab for diagnostic or therapeutic procedures. The risk of significant cardiovascular events in patients with PH is related to the severity of the PH. Patients with suprasystemic pulmonary arterial pressure (PAP) are at high risk for morbidity and mortality. While it is important to maintain hemodynamics as close to baseline as possible for diagnostic procedures, vasopressors or inotropic agents are sometimes required to preserve appropriate coronary perfusion and myocardial function. \r\n\r\nPhenylephrine has a long history of successful use by anesthesiologists. Its main advantage is it increases the systemic vascular resistance (SVR) more than it does pulmonary vascular resistance (PVR), and thus helps minimize leftward shift of the ventricular septum, improving coronary perfusion and ventricular performance overall. Siehr et al. published a pilot study in 15 pediatric patients with severe pulmonary hypertension undergoing cardiac catheterization, comparing phenylephrine, epinephrine, and vasopressin. Phenylephrine did decrease the PVR:SVR ratio to slightly below 1.0 in some patients but had a more variable effect on PVR than norepinephrine or vasopressin, especially in patients with suprasystemic PH.\r\n\r\nNorepinephrine has been a first-line agent in both pediatric and adult PH. It is a powerful systemic vasoconstrictor, a mild inotrope and overall improves right ventricle to pulmonary artery coupling as well as coronary perfusion pressure. Studies in the early 2000\u2019s involving neonatal lambs with high-dose norepinephrine (0.5 mcg\/kg\/min) demonstrated both increased PAP and pulmonary blood flow, which supports the hypothesis of a pulmonary vasodilatory effects. Similar studies in human neonates have also suggested norepinephrine might decrease PVR because of a finding of improved oxygenation. However, these studies may have been confounded by the presence of a left-to-right shunt. Moreover, norepinephrine has been shown to increase PVR at high doses in both in vitro and in vivo studies. While it improves the PVR:SVR ratio, this may well be the result of increased SVR and cardiac output. \r\n\r\nArginine vasopressin has become increasingly popular over the last ten years for the treatment of systemic hypotension in the context of elevated PVR. As a non-catecholamine agent, it is effective in acidotic patients such as those in profound shock. While earlier human studies reported conflicting results on the effect of vasopressin on the pulmonary vasculature, more recent publications describe its successful use in PH patients. The aforementioned study by Siehr showed a consistent decrease in the PVR:SVR ratio as well as pulmonary arterial pressure to systemic arterial pressure (PAP:SAP) ratio with the use of vasopressin in the cardiac catheterization lab. An in-vitro study using human radial and pulmonary arteries compared the vasoconstrictor response of phenylephrine, norepinephrine, vasopressin and metaraminol and demonstrated that vasopressin had the weakest pulmonary vasoconstrictive response of these agents. Some animal and human studies have also hypothesized that vasopressin could induce pulmonary vasodilation via stimulation of the V1 receptor induced release of endothelial-derived nitric oxide but this finding remains inconsistent to date.\r\n\r\nThe evaluation and management of PH in the setting of noncardiac surgery has been comprehensively reviewed in a recent scientific statement from the American Heart Association (Rajagopal et al). Vasopressin is the preferred vasoconstrictor for low systemic blood pressure due to its minimal effects on PVR. However, high doses (0.08-0.1 U\/min) should be avoided due to the possibility of coronary vasoconstriction and right ventricular ischemia. Norepinephrine is a suitable alternative to vasopressin. Phenylephrine should be avoided due to its effect on increasing PVR, SVR and causing reflex bradycardia. Although epinephrine may also be considered, it can produce undesirable tachycardia, induce arrhythmias and increased myocardial oxygen consumption. \r\n\r\n\r\n \r\nREFERENCES \r\nSiehr SL, Feinstein JA, Yang W, Peng LF, Ogawa MT, Ramamoorthy C. Hemodynamic Effects of Phenylephrine, Vasopressin, and Epinephrine in Children With Pulmonary Hypertension: A Pilot Study. Pediatr Crit Care Med <\/em>. 2016;17(5):428-437. doi: 10.1097\/PCC.0000000000000716 \r\n\r\nCurrigan DA, Hughes RJ, Wright CE, Angus JA, Soeding PF. Vasoconstrictor responses to vasopressor agents in human pulmonary and radial arteries: an in vitro study. Anesthesiology<\/em>. 2014;121(5):930-936. doi: 10.1097\/ALN.0000000000000430\r\n\r\nTourneux P, Rakza T, Bouissou A, Krim G, Storme L. Pulmonary circulatory effects of norepinephrine in newborn infants with persistent pulmonary hypertension. J Pediatr<\/em>. 2008;153(3):345-349. doi: 10.1016\/j.jpeds.2008.03.007 \r\n\r\nColeman RD, Chartan CA, Mourani PM. Intensive care management of right ventricular failure and pulmonary hypertension crises. Pediatr Pulmonol<\/em>. 2021;56(3):636-648. doi: 10.1002\/ppul.24776\r\n\r\nRajagopal S, Ruetzler K, Ghadimi K et al. Evaluation and management of pulmonary hypertensionin noncardiac surgery: A scientific statement from the American Heart Association. Circulation. 2023; 147:1317-1343. https:\/\/doi.org\/10.1161\/CIR.0000000000001136\r\n\r\n\r\n”,”hint”:””,”answers”:{“22j2j”:{“id”:”22j2j”,”image”:””,”imageId”:””,”title”:”A.\tPhenylephrine”},”85oaz”:{“id”:”85oaz”,”image”:””,”imageId”:””,”title”:”B.\tNorepinephrine”},”4m8ay”:{“id”:”4m8ay”,”image”:””,”imageId”:””,”title”:”C.\tVasopressin”,”isCorrect”:”1″}}}}}