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

{“questions”:{“ifojw”:{“id”:”ifojw”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Meera Gangadharan, MBBS, FAAP, FASA – University of Texas Health Science Center at Houston\/McGovern Medical School, Houston, TX AND Destiny F. Chau, MD -Arkansas Children\u2019s Hospital\/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nA 5-year-old boy presents for urgent needle pericardiocentesis under ultrasound guidance. He has a pericardial effusion with signs of tamponade physiology, including pulsus paradoxus of -20 mmHg. In addition to cardiac tamponade, which of the following diseases is MOST likely to demonstrate abnormal pulsus paradoxus?\r\n”,”desc”:”EXPLANATION \r\nCardiac tamponade is characterized by compression of the cardiac chambers leading to hemodynamic compromise due to excessive pressure from the accumulation of fluid in the pericardial space. As the intrapericardial volume is relatively fixed, the rate of fluid accumulation and the compliance of the pericardial sac determine the pressure change within this space. When fluid accumulates in a short period of time, even small volumes can result in rapid increases in pressure. The elevated pericardial pressure transmits to the cardiac chambers compromising cardiac filling and ultimately decreasing cardiac output. In contrast, chronic pericardial effusions are defined as those that accumulate over a period of time greater than three months, thereby allowing the pericardial cavity to accommodate fluid without serious hemodynamic compromise up until a critical volume is reached at a later time point. The prolonged time course allows for compensatory mechanisms to develop, such as tachycardia, vasoconstriction, and fluid retention. These mechanisms allow for larger volumes to accumulate before tamponade physiology occurs. Common etiologies of pericardial effusions trauma, autoimmune disease, malignancy, connective tissue disorders, and post-pericardiotomy syndrome. \r\n\r\nPatients present with dyspnea, orthopnea, and chest discomfort. Signs include jugular venous distension, systemic hypotension, tachycardia and pulsus paradoxus. Pulsus paradoxus is an exaggeration of the normal decrease in systolic blood pressure of greater than 10 mmHg during normal spontaneous inspiration and is a key diagnostic feature of cardiac tamponade. It results from the effect of ventricular interdependence during the respiratory cycle being exaggerated by tamponade physiology. During inspiration, venous return is augmented which increases right ventricular volume. The increased right ventricular volume causes a shift of the ventricular septum to the left, thereby reducing left ventricular preload leading to a decrease in cardiac output and systemic blood pressure. In patients with large effusions, an electrocardiogram may demonstrate lower voltages and \u201celectrical alternans\u201d, which is characterized by beat-to-beat variation in QRS amplitude and axis due to excessive movement of the heart within the pericardial fluid. Echocardiographic findings include diastolic collapse of the right atrium and right ventricle, and dilation of the inferior vena cava. Pulsus paradoxus is not unique to cardiac tamponade. It is also associated with several other clinical conditions, which include acute asthma, chronic obstructive pulmonary disease exacerbation, and severe hypovolemia. Acute asthma leads to pulsus paradoxus by several mechanisms, including the following: (1) Highly negative intrathoracic pressures during inspiration further augments systemic venous return and decreases left ventricular preload via septal shift; (2) excessively negative intrathoracic pressure during inspiration increases left ventricular afterload; and, (3) lung hyperinflation increases right ventricular afterload by compressing the pulmonary arteries, which further reduces left ventricular preload.\r\n\r\nCardiac tamponade requires treatment with prompt decompression of the pericardial sac to prevent further hemodynamic compromise and cardiovascular collapse. Sedation and anesthesia can lead to cardiovascular collapse by myocardial depression, vasodilation, and blunting of the compensatory sympathetic mechanisms. In addition, positive pressure ventilation can further compromise venous return and exacerbate cardiac chamber compression, increasing the risk of circulatory collapse. Maintenance of compensatory mechanisms such as relative tachycardia, adequate preload, preservation of contractility and spontaneous ventilation are important to maintain cardiac output. Excessive tachycardia and hypotension in the presence of high ventricular end diastolic pressures can also compromise coronary artery perfusion.\r\n\r\nThe key goals of anesthetic management for subxiphoid percardiocentesis are to allow drainage of pericardial fluid while minimizing the risk of cardiovascular collapse. The safest option is usually local infiltration combined with small doses of sedative medications titrated slowly while maintaining spontaneous ventilation. Medications, fluids, and blood products must be immediately available to treat cardiovascular collapse. Depending on the clinical status of the patient, presence of a surgical team with the patient prepped and draped, before induction of anesthesia, may be required in case a subxiphoid incision is necessary emergently. If surgical drainage under general anesthesia is planned, partial drainage of the pericardial fluid under minimal sedation and local anesthesia may improve cardiovascular reserve and improve hemodynamic stability, allowing for safer induction of anesthesia and intubation with positive pressure ventilation.\r\n\r\nA single-center, retrospective study in a tertiary care children\u2019s hospital by Herron et al analyzed their experience with 127 pediatric patients who underwent 153 pericardiocentesis procedures over a 20-year period. The most common etiology of effusion was post-cardiotomy syndrome in 44% of patients. Approximately 60% of the procedures were performed in the cardiac catheterization laboratory. The overall procedural success rate was 92%. Of note, procedures performed at the bedside had a significantly higher failure rate at 17% than those performed in the catheterization laboratory at 1% (p < 0.01). The incidence of adverse events was 4.6%, which included hemopericardium needing emergent surgery, hemopericardium with hypotension, seizure during induction of anesthesia, and needle puncture of the right ventricle.\r\n\r\nThe correct answer is acute asthma, which can result in pulsus paradoxus as explained above. Aortic stenosis characteristically results in a low amplitude and delayed pulse, known as \u201cpulsus parvus et tardus\u201d. This may be better appreciated with an arterial line or spectral Doppler downstream of the aortic valve. Pulsus alternans is an arterial pulse with the pattern of alternating strong and weak beats, which is associated with severe ventricular dysfunction. The most likely mechanism is that the poorly contractile left ventricle has a reduced stroke volume which leads to an increased end-diastolic volume for the subsequent contraction, resulting in alternating weak and strong pulses. Again, this is more easily appreciated if an arterial line is in place.\r\n\r\nREFERENCES \r\nAdler Y, Charron P, Imazio M, et al. 2015 ESC Guidelines for the diagnosis and management of pericardial diseases: The Task Force for the Diagnosis and Management of Pericardial Diseases of the European Society of Cardiology (ESC)Endorsed by: The European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J<\/em>. 2015;36(42):2921-2964. doi:10.1093\/eurheartj\/ehv318\r\n\r\nJohnson J, Horner J, Cetta F. Pericardial Diseases. In: Shaddy RE, Penny DJ, Feltes TF, Cetta, Mital S, eds. Moss and Adams\u2019 Heart Disease in Infants, Children and Adolescents<\/em>. 10th ed. Philadelphia, PA: Wolters Kluwer; 2021:1393-1406.\r\n\r\nMckenzie I, Markakis Zestos M, Stayer S, Andropoulos D. Anesthesia for Miscellaneous Diseases. In: Andropoulos D, Mossad E, Gottlieb, eds. Anesthesia for Congenital Heart Disease<\/em>. 3rd ed. Hoboken, New Jersey: Wiley Blackwell; 2015:615-618.\r\n\r\nSarkar M, Bhardwaj R, Madabhavi I, Gowda S, Dogra K. Pulsus paradoxus. Clin Respir J<\/em>. 2018; 12:2321-2331. \r\n\r\nHerron C, Forbes TJ, Kobayashi D. Pericardiocentesis in children: 20-year experience at a tertiary children\u2019s hospital. Cardiol Young<\/em>. 2022; 32 (4): 606\u2013611. doi: 10.1017\/S104795112100278X”,”hint”:””,”answers”:{“6y5pa”:{“id”:”6y5pa”,”image”:””,”imageId”:””,”title”:”A. Aortic stenosis”},”r44ts”:{“id”:”r44ts”,”image”:””,”imageId”:””,”title”:”B. Acute asthma”,”isCorrect”:”1″},”d9pek”:{“id”:”d9pek”,”image”:””,”imageId”:””,”title”:”C. Severe ventricular dysfunction”}}}}}

{“questions”:{“60trt”:{“id”:”60trt”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Meera Gangadharan, MBBS, FAAP, FASA – Children\u2019s Memorial Hermann Hospital, McGovern Medical School, Houston, TX AND Destiny F. Chau, MD – Arkansas Children\u2019s Hospital\/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nA 15-year-old boy palliated with the Fontan procedure has a history of plastic bronchitis refractory to maximal medical treatment. A diagnostic cardiac catheterization demonstrates a patent Fontan pathway with an open fenestration, Fontan pressure of 15 mm Hg, a pulmonary vascular resistance of 2.5 Woods units, and a transpulmonary gradient of 5 mm Hg with a baseline SpO2 of 92% in room air. Which of the following interventions is MOST appropriate for the management of the patient\u2019s plastic bronchitis?”,”desc”:”EXPLANATION \r\nThe Fontan physiology has a significant adverse impact on the lymphatic system. Chronic venous hypertension characterizing the Fontan circulation causes a shift in Starling forces, which favors fluid accumulation in the interstitial tissue. Additional demand for lymphatic fluid clearance may be due to the following: 1) hypoalbuminemia; 2) increased lymph production due to elevated inferior vena cava pressure and hepatic congestion; 3) diaphragmatic dysfunction leading to flow reversal in the portal vein; 4) direct capillary leak due to endothelial dysfunction; 5) low cardiac output and, 6) direct injury to lymphatic structures, such as the thoracic duct, during surgical procedures. Lymphatic vessels become tortuous, dilated, and develop collaterals to accommodate the increased volume and abnormal flow of lymphatic fluid. Inadequate lymph drainage leads to the development of pleural effusions, chylothorax, ascites, protein losing enteropathy and plastic bronchitis. These are all components of a \u201cfailed Fontan circulation\u201d and lead to increased morbidity and mortality. \r\n\r\nPlastic bronchitis has a prevalence of approximately 4-5% in Fontan patients and is associated with a 5-year mortality of up to 50%. The exudation of proteinaceous material into the airways can lead to cast formation, potentially resulting in significant respiratory symptoms and total airway obstruction. Medical management includes airway clearance, bronchodilators, aggressive chest physiotherapy, mucolytic therapy with N-acetylcysteine and\/or dornase-alpha, diuretics, pulmonary vasodilators, aerosolized tissue plasminogen activator, aldosterone inhibitors and a low-fat diet to decrease lymphatic fluid production and flow.\r\n\r\nFollowing failure of medical therapy and after fully addressing reversible causes of lymphatic failure, interventions to decompress the lymphatic system or to occlude abnormal lymphatic vessels are the next options. There are several interventions for lymphatic decompression including surgical decompression, percutaneous thoracic duct decompression, thoracic duct stenting, and creation of a lymphovenous anastomosis. Occlusion techniques include lymphatic embolization, thoracic duct embolization, selective lymphatic duct embolization and thoracic duct ligation. Thoracic duct decompression is surgically accomplished with anastomosis of the left innominate vein to the common atrium. The major disadvantages of this procedure include the need for cardiopulmonary bypass, creation of a right-to-left shunting with resultant cyanosis, and the unknown long-term consequences of lymphatic return directly to the systemic circulation that bypasses the pulmonary circulation. Perhaps the most efficacious option is orthotopic heart transplantation, which is typically reserved for end-stage \u201cfailing Fontan\u201d physiology. However, in recent years, the central role of the lymphatic system in the pathophysiology of plastic bronchitis has been recognized, and percutaneous lymphatic intervention has emerged as an additional therapeutic approach for plastic bronchitis prior to heart transplantation. \r\n\r\nDori et al reported the results of selective lymphatic embolization using Dynamic Contrast-enhanced Magnetic Resonance Lymphangiography (DCMRL) and T2-weighted MRI in 17 of 18 total patients with plastic bronchitis. They were followed for a median of 315 days, with 88% experiencing significant symptomatic improvement, including temporary resolution of cast formation. The procedure involved identifying a target lymphatic vessel by injecting contrast into the inguinal lymph nodes followed by MR imaging to illustrate the passage of contrast through the lymphatic system in real time, allowing for identification of lymphatic leakage and flow disturbances. MRI or lymphangiogram or both illustrated retrograde lymphatic flow toward the lung parenchyma in 16 patients. Of the 18 patients, 17 underwent either embolization or thoracic duct stenting, thereby rerouting lymphatic flow to provide a measure of symptomatic relief and improvement in quality of life. Clearly however, these procedures do not address the root cause of elevated central venous pressures and continued attention to optimization of the Fontan physiology\/pathway is imperative. \r\n\r\nThe patient in the stem has an open fenestration and Fontan hemodynamics that are within the expected range. There is also normal pulmonary vascular resistance, and the transpulmonary gradient is not elevated. Thus, balloon dilation of the fenestration and treatment with bosentan will be of minimal benefit. Given the failure of maximal medical therapy, selective lymphatic embolization should be considered as the next treatment modality and prior to orthotopic heart transplantation, though often a curative treatment for plastic bronchitis. Unfortunately, selective lymphatic embolization is performed at very few centers currently, which may necessitate the use of other treatment modalities mentioned earlier in the explanation (i.e. thoracic duct ligation).\r\n\r\n \r\nREFERENCES \r\nRychik J, Atz AM, Celermajer DS, et al. Evaluation and management of the child and adult with Fontan circulation: A scientific statement from the American Heart Association. Circulation<\/em>. 2019;140(6):e234-e284. \r\n\r\nRoch\u00e9Rodr\u00edguez M, DiNardo JA. The lymphatic system in the Fontan patient-pathophysiology, imaging, and interventions: what the anesthesiologist should know. J Cardiothorac Vasc Anesth<\/em>. 2022;36(8 Pt A):2669-2678. \r\n\r\nDori Y, Keller M, Rome J, et al. Percutaneous lymphatic embolization of abnormal pulmonary lymphatic flow as treatment of plastic bronchitis in patients with congenital heart disease. Circulation<\/em>. 2016;133:1160-1170.”,”hint”:””,”answers”:{“b3yf2”:{“id”:”b3yf2″,”image”:””,”imageId”:””,”title”:”A) Selective lymphatic embolization “,”isCorrect”:”1″},”nxgzu”:{“id”:”nxgzu”,”image”:””,”imageId”:””,”title”:”B) Balloon dilation of Fontan fenestration”},”brlfw”:{“id”:”brlfw”,”image”:””,”imageId”:””,”title”:”C) Initiation of Bosentan\r\n\r\n”}}}}}

{“questions”:{“ibb1f”:{“id”:”ibb1f”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Sana Ullah, MB, ChB, FRCA – Children\u2019s Medical Center, Dallas, TX \r\n\r\nA previously healthy 14-year-old girl is undergoing evaluation for pulmonary hypertension due to a strong family history. Which of the following gene mutations is MOST likely to be present in this patient?”,”desc”:””,”hint”:””,”answers”:{“mdeo1”:{“id”:”mdeo1″,”image”:””,”imageId”:””,”title”:”A. JAG1″},”43x7a”:{“id”:”43x7a”,”image”:””,”imageId”:””,”title”:”B. BMPR2″,”isCorrect”:”1″},”si9w3″:{“id”:”si9w3″,”image”:””,”imageId”:””,”title”:”C. PTPN11″}}}},”results”:{“m9iyu”:{“id”:”m9iyu”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:””,”redirect_url”:”https:\/\/ccasociety.org\/wp-content\/uploads\/2024\/05\/CCAS-QOW-Posted-5-9-2024.pdf”}}}

{“questions”:{“kadbs”:{“id”:”kadbs”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:”https:\/\/ccasociety.org\/wp-content\/uploads\/2024\/05\/CCAS-Graphic-522024.jpg”,”imageId”:”7313″,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: JE Elliott, MD, Dept of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston\/McGovern Medical School, Houston, TX AND\r\nM Gangadharan, MBBS, FAAP, FASA, Dept of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston\/McGovern Medical School, Houston, TX \r\n\r\nA three-day-old boy with significant cardiomegaly has a transthoracic echocardiogram that demonstrates a globular appearing left ventricle with severely depressed systolic function. Several transthoracic echocardiographic images are illustrated below. Which of the following types of cardiomyopathies is MOST likely present in this patient? \r\n\r\n”,”desc”:”EXPLANATION \r\nNon-compaction cardiomyopathy was considered a rare condition but is being increasingly diagnosed because of heightened awareness. The left ventricular myocardium of patients with non-compaction cardiomyopathy is characterized by prominent trabeculations and deep intertrabecular recesses which communicate with the ventricular cavity. Non-compaction cardiomyopathy results from a defect in normal myocardial development. The primitive myocardium is a trabecular network of sponge-like muscle fibers in the mid-late embryo, and receives its blood supply from intertrabecular spaces that communicate with the cardiac chambers. During normal development, these trabeculations disappear after epicardial coronary arterial supply has been established. Subsequently, the spongy myocardium is transformed into the compact normal myocardium. Non-compaction results when this transformation from spongy to compact myocardium fails to occur, resulting in an inner prominent spongy layer with a thin outer compact epicardial layer. \r\n\r\nClinically, non-compaction cardiomyopathy is characterized by heart failure, arrhythmias and thromboembolic events that may present at any age. There are several subtypes of left ventricular noncompaction cardiomyopathy (LVNC) and these different phenotypes have prognostic implications. The subtypes are: (1) Isolated non-compaction with normal cardiac function; (2) non-compaction with hypertrophic cardiomyopathy (HCM), and, (3) Non-compaction with dilated cardiomyopathy (DCM). A 2015 study by Jeffries et al, based on the Pediatric Cardiomyopathy Registry, investigated time to death or transplantation in patients with different phenotypes of LVNC. They observed that children with isolated LVNC had the best outcomes followed by LVNC with HCM. LVNC with DCM resulted in the worst patient outcomes. LVNC may be also associated with a variety of congenital heart defects including anomalous coronary arteries, atrial and ventricular septal defects, Ebstein\u2019s anomaly, transposition of the great arteries, absent pulmonary valve, pulmonary stenosis, hypoplastic left heart syndrome, and anomalous pulmonary veins. Reversible forms of LVNC have been reported to occur when the left\/systemic ventricle is subjected to abnormal loading conditions such as during pregnancy and remodeling of the right ventricle in corrected transposition of the great vessels.\r\n\r\nAlthough echocardiography is the most common modality used to confirm diagnosis, there are not widely accepted criteria that constitute a gold standard for the diagnosis of LVNC. However, there is general agreement that LVNC is defined by presence of the following characteristics: (1) prominent trabeculations in the left ventricle; (2) deep recesses between the trabeculations and the presence of a thin compacted layer; and (3) a ratio > 2:1 of the noncompacted to compacted myocardial layers at end-systole. Cardiac magnetic resonance (CMR) is also being increasingly utilized to delineate the non-compacted muscle layer and to better visualize the cardiac apex, in addition to measuring ejection fraction. Cardiac fibrosis can also be evaluated with the use of late gadolinium enhancement during CMR.\r\n\r\nManagement should follow evidence-based guidelines for the specific phenotype of LVNC. Heart failure is managed according to standard guidelines. These patients are at increased risk for thromboembolic events such as stroke and may require anticoagulation. Typically, most patients are started on oral aspirin therapy but may require additional medications such as warfarin if there are other risk factors such as reduced ejection fraction or atrial fibrillation. Ventricular arrhythmias are common, and these patients may need placement of a defibrillator to prevent sudden death. First-degree relatives should be screened as one study demonstrated that 30% of the relatives screened by echocardiography were found to have LVNC.\r\n\r\nNeonatal non-compaction cardiomyopathy appears to be associated with particularly poor outcomes. In a small retrospective analysis by Rodrigues-Fanjul et al, the mortality rate of 14 neonates with non-compaction cardiomyopathy was 42.8% (6) over a median follow-up period of 34 months. Five of the six deaths were from ventricular failure. The presence of biventricular involvement and poor ventricular function were associated with a higher risk of death. \r\n\r\nEchocardiographic features of hypertrophic cardiomyopathy (HCM) include wall thickness > 15mm, asymmetrical hypertrophy, systolic anterior motion of the mitral valve (SAM), and a small LV cavity. Echocardiographic features of dilated cardiomyopathy (DCM) include left ventricular (LV) dilation (>112%, corrected for age and body surface area) and systolic dysfunction (LV ejection fraction < 45%) with impaired global contractility (fractional shortening < 25%). Although subsets of noncompaction cardiomyopathy include dilated and hypertrophic forms, the presence of trabeculations in both ventricles make biventricular noncompaction cardiomyopathy the most likely diagnosis in the patient presented in the stem. \r\n\r\n\r\n \r\nREFERENCES \r\nIchida F. Left ventricular noncompaction – Risk stratification and genetic consideration. J Cardiol<\/em>. 2020;75(1):1-9. doi:10.1016\/j.jjcc.2019.09.011\r\n\r\nJeffries JJ, Wilkinson JD, Sleeper LA et al. Cardiomyopathy phenotypes and outcomes for children with left ventricular myocardial noncompaction: Results from the Pediatric Cardiomyopathy Registry. J Cardiac Fail<\/em>. 2015; 21:877-884.\r\n\r\nCE Bennett and R Freudenberger. The Current Approach to Diagnosis and Management of Left Ventricular Noncompaction Cardiomyopathy: Review of the Literature. Cardiology Research and Practice<\/em>. Volume 2016, Article ID 5172308, 1-7. \r\n\r\nJ Rodriguez-Fanjul, S Tubio-Comez, JMC Bellon, C Bautista-Rodriguez, and J Sanchez-de-Toledo. Neonatal Non-compacted Cardiomyopathy: Predictors of Poor Outcome. Pediatric Cardiology<\/em>. 2020; 41:175-180.\r\n\r\nMaron BJ, Desai MY, Nishimura RA, et al. Diagnosis and Evaluation of Hypertrophic Cardiomyopathy: JACC State-of-the-Art Review. J Am Coll Cardiol<\/em> 2022;79(4):372-389. doi:10.1016\/j.jacc.2021.12.002\r\n\r\nMathew T, Williams L, Navaratnam G, et al. Diagnosis and assessment of dilated cardiomyopathy: a guideline protocol from the British Society of Echocardiography. Echo Res Pract. 2<\/em>017;4(2):G1-G13. doi:10.1530\/ERP-16-0037\r\n\r\n”,”hint”:””,”answers”:{“7mu8b”:{“id”:”7mu8b”,”image”:””,”imageId”:””,”title”:”A.\tDilated Cardiomyopathy”},”e3vfc”:{“id”:”e3vfc”,”image”:””,”imageId”:””,”title”:”B.\tNon-compaction cardiomyopathy”,”isCorrect”:”1″},”hx25y”:{“id”:”hx25y”,”image”:””,”imageId”:””,”title”:”C.\tHypertrophic Cardiomyopathy\r\n\r\n”}}}}}

{“questions”:{“og24v”:{“id”:”og24v”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Fernando Cuadrado, MD – Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, OH and\r\nDestiny F. Chau, MD – Arkansas Children\u2019s Hospital\/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nA 7-year-old boy with a history of pulmonary arterial hypertension treated with sildenafil and ambrisentan presents for cardiac catheterization. After induction of anesthesia, the blood pressure decreases from 98\/50 to 60\/40 mmHg along with a decrease in oxygen saturation from 97% from 88%. Which of following medications is the MOST appropriate treatment for hypotension in this patient?\r\n”,”desc”:”EXPLANATION \r\nPulmonary arterial hypertension (PAH) is defined as mean pulmonary artery pressure (mPAP) greater than 20 mmHg and a pulmonary vascular resistance (PVR) greater than 3 Woods units (WU) in adults and children older than three months of age. Chronically elevated PAP and PVR can significantly impair the right ventricle\u2019s (RV) function over time due to long-standing pressure overload and RV hypertrophy with subsequent diastolic dysfunction and impaired ventricular filling. This may lead to downstream adverse effects on left ventricular (LV) filling and systemic cardiac output as RV function deteriorates. LV function and systemic cardiac output is further compromised with leftward shift or bowing of the interventricular septum into the LV cavity. Due to interventricular dependence, this leftward shift of the ventricular septum negatively affects LV geometry leading to further impaired function. Additionally, RV hypertrophy significantly increases wall tension of the myocardium resulting in increased myocardial oxygen demand and the mean arterial pressure required to maintain adequate coronary perfusion pressure. \r\n\r\nSystemic hypotension and thus reduced coronary perfusion pressure can easily lead to myocardial ischemia and further reduced myocardial function, resulting in a vicious cycle if not treated expeditiously. A hypertrophied RV has very little reserve for coronary hypoperfusion and promptly fails. Rapid treatment of hypotension is essential to preserve coronary perfusion pressure (CPP) and maintain oxygen delivery to the RV at risk for acute decompensation. Pulmonary hypertensive (PH) crisis is a sudden increase in PVR leading to RV failure with subsequent decreased LV preload, cardiac output and coronary perfusion. Cardiac arrest will ensue very quickly if PH crisis is not treated aggressively and rapidly. \r\n\r\nAs mentioned previously, prompt treatment of hypotension is necessary to prevent further deterioration in RV function and RV failure in patients with PH. Several vasoactive medications can be used to increase SVR and maintain coronary perfusion pressure. Vasopressin is the optimal choice to increase SVR, spare PVR, and thereby raise MAP and CPP without increasing heart rate and myocardial oxygen consumption. At moderate to high doses, epinephrine increases SVR, MAP, heart rate and myocardial contractility, as well as PVR. Likewise, dopamine, when used at the higher end of its dosing range, increases SVR, heart rate, MAP, myocardial contractility, and PVR. In addition to their undesirable effects on PVR, both epinephrine and dopamine increase heart rate, thereby shortening diastolic filling time and increasing myocardial oxygen demand, which can be highly detrimental for an RV at high risk of failure. Phenylephrine is a more readily available and commonly used vasoactive medication that increases SVR and MAP leading to a reflex decrease in heart rate. It may be used in this clinical scenario as well. However, it is a less optimal choice compared to vasopressin due to an undesirable effect of increasing PVR. \r\n\r\n\r\nOf the three answer choices in the stem, vasopressin is the ideal drug for treating hypotension in patients with pulmonary hypertension due to minimal effects on PVR. Although other vasoactive agents may be used, they may be associated with detrimental increases in PVR and undesired tachycardia with resultant increased myocardial oxygen demand and shortened diastolic filling time. \r\n\r\n\r\n \r\nREFERENCES \r\nWadia RS, Bernier ML, Diaz-Rodriguez NM, Goswami DK, Nyhan SM, Steppan J. Update on perioperative pediatric pulmonary hypertension management. J Cardiothorac Vasc Anesth<\/em>. 2022;36(3):667-676.\r\n\r\nTriposkiadis F, Giamouzis G, Boudoulas KD, et al. Left ventricular geometry as a major determinant of left ventricular ejection fraction: physiological considerations and clinical implications. Eur J Heart Fail<\/em>. 2018;20(3):436-444.\r\n\r\nKaestner M, Schranz D, Warnecke G, Apitz C, Hansmann G, Miera O. Pulmonary hypertension in the intensive care unit. Expert consensus statement on the diagnosis and treatment of paediatric pulmonary hypertension. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK. Heart<\/em>. 2016;102 Suppl 2:ii57-ii66.\r\n”,”hint”:””,”answers”:{“j9ub1”:{“id”:”j9ub1″,”image”:””,”imageId”:””,”title”:”A.\tEpinephrine “},”cs074”:{“id”:”cs074″,”image”:””,”imageId”:””,”title”:”B.\tVasopressin”,”isCorrect”:”1″},”ohjcn”:{“id”:”ohjcn”,”image”:””,”imageId”:””,”title”:”C.\tDopamine”}}}}}