Perioperative Management of Pheochromocytoma: Focus on Magnesium, Clevidipine, and Vasopressin

The effects of perioperative dexmedetomidine infusion on hemodynamic stability during laparoscopic adrenalectomy for pheochromocytoma: a randomized study

Introduction

Pheochromocytoma is a rare catecholamine-producing neuroendocrine tumor originating from the adrenal medulla chromaffin cells. Hemodynamic instability can occur during the induction of anesthesia and surgical manipulation of the tumor. This study investigated the effects of intraoperative dexmedetomidine administration on hemodynamic stability in patients undergoing laparoscopic adrenalectomy for pheochromocytoma.

Methods

Forty patients who underwent laparoscopic adrenalectomy for pheochromocytoma were randomly assigned to the dexmedetomidine (n = 20) or control (n = 20) group. The primary outcome of this study was intraoperative hemodynamic stability, and the secondary endpoint was the plasma catecholamine concentrations, specifically of epinephrine and norepinephrine.

Results

The intraoperative maximum blood pressures were significantly lower in the dexmedetomidine group (control vs. dexmedetomidine group: 182 ± 31 vs. 161 ± 20, 102 ± 17 vs. 90 ± 10, and 128 ± 22 vs. 116 ± 12 [mean ± SD] mmHg and p = 0.020, 0.015, and 0.040 for systolic, diastolic, and mean blood pressure, respectively). The maximum heart rate during surgery was 108 ± 15 bpm in the control group and 95 ± 12 bpm in the dexmedetomidine group (p = 0.010). Other parameters of hemodynamic instability were comparable between both groups. Plasma catecholamine concentrations did not differ between the groups.

Conclusion

Dexmedetomidine infusion following the induction of anesthesia at a rate of 0.5 μg/kg/h significantly attenuated the maximum intraoperative SBP, DBP, MBP, and HR, contributing to improved hemodynamic stability.

Successful surgical removal of a pheochromocytoma in a mare via trans-costal approach

BACKGROUND

Pheochromocytomas have been previously reported in horses, but successful antemortem diagnosis and surgical removal without recurrence of clinical signs have not been described.

OBJECTIVE

To report the clinical presentation, diagnostic evaluation, surgical technique, anaesthetic management and post-operative care of a mare diagnosed with pheochromocytoma.

STUDY DESIGN

Clinical case report.

METHODS

An 18-year-old Quarter Horse mare presented for recurrent episodes of colic, profuse sweating, muscle fasciculations and agitation over a 2-month period. Clinical, clinicopathologic and ultrasonographic (transcutaneous, transrectal) abnormalities were consistent with a unilateral left-sided adrenal mass. Surgical removal of the mass was performed via a trans-costal approach with removal of the 18th rib and retraction of the left kidney to improve exposure. Associated vasculature was ligated, and the adrenal mass was removed and submitted for histopathology and immunohistochemistry.

RESULTS

A trans-costal surgical approach provided excellent visualisation of the adrenal mass and allowed for identification and ligation of associated vessels. Total surgical and anaesthesia time were 86 and 114 min, respectively. Several intraoperative (hypertension, tachycardia) and post-operative (colic with tachycardia, tachypnea, large colon pelvic flexure impaction and nasogastric reflux) complications were encountered and managed successfully. Immunohistochemistry demonstrated positive labelling for synaptophysin and chromogranin A, confirming diagnosis of pheochromocytoma. The mare had recovered well at 6-week recheck post-operatively and returned to training at 6 months post-operatively. No further clinical signs consistent with pheochromocytoma have been observed following removal.

CONCLUSIONS

The trans-costal approach allowed for surgical removal of a pheochromocytoma in a mare. Surgical removal of adrenal masses in horses may be associated with complications yet was successfully performed without subsequent recurrence of clinical signs associated with tumour presence and return to athletic use in this mare.

Deliberate Compensated Vasoplegia-A Novel Pharmaceutical Approach for Controlling Blood Pressure During Surgery for Pheochromocytoma

BACKGROUND

The most dreaded adverse event of pheochromocytoma surgery is operative severe blood pressure fluctuations. Preoperative protocols with alpha-blockade have achieved controversial results. No study to date evaluated the use of operative protocols in pheochromocytoma patients. Deliberated compensated vasoplegia (DCV) is a novel pharmaceutical regimen developed at our institution to decrease severe hypertensive events. The aim of this study is to compare outcomes of pheochromocytoma resection with and without DCV protocol.

METHODS

A retrospective analysis of all pheochromocytoma resections between the years 2012 and 2021 was performed. Resections performed with and without DCV protocol were compared. The primary outcome measured was the incidence of severe hypertension (MAP > 150 mmHg) during surgery. Secondary outcomes included other abnormal blood pressure measurements as well as perioperative data and complications.

RESULTS

A total of 41 resections were included, 21 performed under DCV protocol, and 20 without the protocol. Analysis demonstrated no significant difference in preoperative parameters including tumor size, catecholamine levels, and preoperative alpha-blockade protocol. The use of DCV protocol resulted in significant decrease in severe hypertension incidence from 1.95 ± 3.6 to 0.03 ± 0.13 events/h, p = 0.008. Application of the DCV protocol was not associated with any other adverse events.

CONCLUSIONS

This study suggests that DCV anesthesia protocol significantly decreases the incidence of severe hypertensive episodes during pheochromocytoma resection. This is the first study that describes a highly effective protocol for controlling hypertension in pheochromocytoma patients.

Hydroxocobalamin to treat refractory vasoplegia following phaeochromocytoma resection in a child

Phaeochromocytomas and paragangliomas are rare neuroendocrine tumours that often secrete catecholamines, which can cause dramatic swings in blood pressure and end‐organ damage. During surgical resection of these tumours, antihypertensive drug infusions are often required, but after resection patients may become vasoplegic, in part due to cessation of catecholamine secretion by the tumour in the context of pre‐operative α₁ adrenoceptor antagonism. Numerous medications have been used to treat vasoplegia in this setting, including noradrenaline, vasopressin and, more recently, angiotensin II. We report the case of a patient who experienced vasoplegia after phaeochromocytoma resection which was refractory to vasopressin and angiotensin II infusions but was successfully treated with high dose hydroxocobalamin.

Intraoperative Analgesia with Magnesium Sulfate versus Remifentanil Guided by Plethysmographic Stress Index in Post-Bariatric Dermolipectomy: A Randomized Study

BACKGROUND

Magnesium sulfate reduces pain scores and analgesic consumption. Its use as an analgesic resource in opioid-free or opioid-sparing techniques have also been tested. The evaluation of the antinociceptive potency of drugs and doses indirectly, through hemodynamic oscillations has been questioned. A relatively new algorithm called the plethysmographic stress index has been considered sensitive and relatively specific as a parameter for assessing the need for intraoperative analgesia.

OBJECTIVES

The aim of this trial was to assess the intraoperative analgesic capacity of magnesium sulfate compared to remifentanil. The secondary objectives were propofol consumption and its latency, the consumption of opioids, ephedrine, and cisatracurium. Patients and Methods. Forty patients scheduled for post-bariatric dermolipectomy were randomly assigned to two groups to receive total intravenous anesthesia with target-controlled hypnosis induced with propofol. Analgesia was obtained in the remifentanil group with remifentanil at an initial dose of 0.2 μg·kg-1·min-1 and in the magnesium sulfate group with magnesium sulfate 40 mg·kg-1 + 10 mg·kg-1·h-1.

RESULTS

There was no statistical hemodynamic difference between the groups before and after orotracheal intubation (p = 0.062) and before and after the surgical incision (p = 0.656). There was also no statistical difference in the variation of mean arterial pressure before and after intubation (p = 0.656) and before and after the surgical incision (p = 0.911). There was similar consumption of cisatracurium, ephedrine, and postoperative opioids between the groups. Some patients in the magnesium sulfate group needed more intraoperative fentanyl and propofol, although the latency of propofol was similar in both the groups.

CONCLUSION

We conclude that using magnesium sulfate in intravenous general anesthesia for post-bariatric dermolipectomy is related to a significant reduction in opioid consumption without compromising hemodynamic stability. Overall, PSI monitoring was helpful in driving the analgesic strategy. The use of magnesium sulfate proved to be an important adjunct in the scenario presented, allowing the use of opioids to be avoided in certain cases. We found no statistical differences in the consumption of neuromuscular blocker and vasoconstrictor. Substituting opioids for magnesium sulfate leads to an increase in propofol consumption in the scenario presented. Studies with a larger sample are needed to corroborate the results presented and evaluate other potential advantages in reducing opioid consumption.

Anaesthetic Management of a Labrador Retriever Undergoing Adrenalectomy for Phaeochromocytoma Excision, a Case Report

Perioperative management of cases undergoing phaeochromocytoma removal should aim at normalising blood pressure and heart rate, restoring volume depletion, and preventing catecholamine release induced by surgical manipulation. In this case report, a novel pharmacological approach in a dog undergoing surgical tumour excision is described. A 7-year-old 25-kg spayed female Labrador Retriever presented for repeated episodes of generalised weakness, pale mucous membranes, tachycardia, tremor, panting, vomiting, and hypertension over the last month was referred for surgical treatment of a left-sided adrenal tumour with invasion of the caudal vena cava. Severe hypertensive episodes occurred repeatedly, starting early during the anaesthetic period, while clipping and cleaning the abdominal area, and continued intraoperatively when the tumour was handled. Moderate hypotension occurred once the tumour was isolated and worsened during temporary caudal vena cava flow interruption and cavotomy. The patient was treated preoperatively with phenoxybenzamine to prevent hypertensive crises. Intraoperatively, magnesium sulphate and urapidil were used to control blood pressure. This treatment was effective in reducing the magnitude of blood pressure spikes but not sufficient to prevent hypertensive peaks, especially during tumour manipulation. Hypotension was treated with synthetic colloid and crystalloid boli, and noradrenaline continuous infusion. Blood transfusion was performed in response to acute bleeding during cavotomy. The dog recovered successfully from anaesthesia and its quality of life was deemed excellent by the owner at the last follow up, 22 months after surgery. The histopathology confirmed the diagnosis of phaeochromocytoma with an invasion of the phrenicoabdominal vein. In the present case, we obtained a successful outcome but failed to provide haemodynamic stability throughout the procedure.

Intraoperative adenosine for pheochromocytoma with myocardial infarction and SARS-CoV-2. Case report

Introduction: Pheochromocytomas are neuroendocrine tumors capable of synthetizing, storing and releasing catecholaminergic hormones that may lead to life-threatening hemodynamic instability. The COVID-19 pandemic has increased the risks and perioperative complexity of the patients undergoing pheochromocytoma-associated adrenalectomy. This article discusses the use of adenosine for the management of hypertensive crisis during this intervention, as well as the need to individualize the suitable timing for surgery after recent COVID-19 infection. Case presentation: This article discusses the case of a patient with a finding of right adrenal incidentaloma; further studies determined a metanephrines secreting pheochromocytoma. Following hospital admission for preoperative optimization, the eve of the procedure the patient developed an acute myocardial infarction and subsequently SARS-CoV-2 symptomatic infection. Intraoperatively, hypertensive peaks were managed with continuous adenosine perfusion. The patient was discharged after 48 hours. Conclusions: Preoperative optimization positively influences the intraoperative management of patients with pheochromocytoma. The intraoperative use of adenosine allows for adequate and safe control of hypertensive crises. Each situation must be individualized in patients pending surgery, with a recent COVID-19 infection.

Pheochromocytoma, Fulminant Heart Failure, and a Phenylephrine Challenge. The Perioperative Management of Adrenalectomy in a Jehovah’s Witness Patient: A Case Report

Perioperative management of pheochromocytoma in the setting of catecholamine-induced heart failure requires careful consideration of hemodynamic optimization and possible mechanical circulatory support. A Jehovah’s Witness patient with catecholamine-induced acutely decompensated heart failure required dependable afterload reduction for a cardio-protective strategy. This was emphasized due to the relative contraindication to perioperative anticoagulation required for mechanical circulatory support. A phenylephrine challenge clearly demonstrated adequate alpha blockade after only 24 hours of phenoxybenzamine treatment. This resulted in advancement of the surgery date. This case also highlights management of beta blockade, volume and salt loading, autologous blood transfusion, and profound post-operative vasoplegia in the setting of cardiogenic shock. Careful attention to hemodynamic optimization and cardio-protective strategies ultimately resulted in positive outcome for this challenging clinical scenario.

Hypertensive crisis precatheter ablation for resistant atrial fibrillation: a case of undiagnosed bilateral pheochromocytomas

A 63-year-old man with hypertension was referred for catheter ablation of persistent atrial fibrillation. He was diagnosed with paroxysmal atrial fibrillation approximately 6 years prior. Over the previous 12 months, his atrial fibrillation had become persistent despite medication optimisation for rate control and elective cardioversion. Sinus rhythm was restored briefly. The decision was made to pursue catheter ablation and isolation of the pulmonary veins. On anaesthetic induction, the patient suffered from a hypertensive crisis. The procedure was aborted, and the patient was admitted to hospital for investigations of secondary hypertension. Ultimately, the patient was diagnosed with bilateral pheochromocytomas. This case outlines the diagnostic challenges and cardiac comorbidities associated with bilateral pheochromocytomas.

Recurrent Stress Cardiomyopathy: A Rare Variant in a Young Patient with Undiagnosed Pheochromocytoma

Biventricular stress cardiomyopathy is one of several known anatomical variants of reversible cardiomyopathies to occur. We present a case of a young patient with recurrent stress cardiomyopathy complicated by cardiogenic shock in the perioperative period. The cardiomyopathy observed was in a patient with neurofibromatosis type I and undiagnosed pheochromocytoma who presented for intervention of hydrocephalus. This case demonstrates the importance of vigilance in the young patient who develops shock in the perioperative period.

Endocrine emergencies in anesthesia

PURPOSE OF REVIEW

An increasing number of patients with endocrine disorders will present to the operating rooms. In this review, we outline the common endocrine disorders that the anesthesiologist may face in the perioperative time span, review the controversies in optimal management, as well as summarize the recent literature for the management of these complex patients.

RECENT FINDINGS

Perioperative management of pheochromocytoma and paraganglioma has been facilitated by improved medical management and the adoption of minimally invasive surgical techniques. An improved understanding of the sequelae of carcinoid syndrome has resulted in safer perioperative management. Perioperative glycemic management requires a fundamental understanding of perioperative fluid resuscitation and adverse events associated with the new generation oral hyperglycemic agents to prevent avoidable complications.

SUMMARY

Endocrine disorders will commonly present in the perioperative time period and the anesthesiologist plays a critical role in achieving good operative outcomes.

Approach to the Patient: Perioperative Management of the Patient with Pheochromocytoma or Sympathetic Paraganglioma

Pheochromocytomas and sympathetic paraganglioma (PPGL) are rare chromaffin cell tumors originating in the adrenal medulla and sympathetic paraganglia, respectively, which share the capacity to synthesize and release catecholamines. The incidence of PPGL has increased in recent years. Surgical resection is the only curative treatment for PPGL. Management of patients with PPGL is complex and should be done by a specialized multidisciplinary team in centers with broad expertise. Surgical resection of a PPGL is a high-risk procedure for which optimal pretreatment with antihypertensive drugs is required in combination with state-of-the-art surgical procedures and anesthesiological techniques. In this article we discuss the underlying evidence and the pros and cons of presurgical medical preparation. Finally, the areas of uncertainty and controversies in this field are addressed.

[Perioperative pharmacological circulatory support in daily clinical routine]

Perioperative phases of hypotension are associated with an increase in postoperative complications and organ damage. Whereas some years ago hemodynamic stabilization was primarily carried out by volume supplementation, in recent years the use and dosing of cardiovascular-active substances has significantly increased. But like intravascular volume therapy, also substances with a cardiovascular effect have therapeutic margins, and thus, potential side effects. This review article discusses indications for each cardiovascular-active agent, weighing up advantages and disadvantages. Special attention is paid to the question how to administrate them: central venous catheter vs. peripheral indwelling venous cannula. The authors come to the conclusion that it is not a question of whether it is principally allowed to apply cardiovascular-active drugs via peripheral veins but more importantly, what should be taken into consideration if a peripheral venous access is used. This article provides concise recommendations.

Pharmacokinetics of magnesium and its effects on clinical variables following experimentally induced hypermagnesemia

The objectives of this study were to describe pharmacokinetic and pharmacodynamic changes as a result of a single intravenous administration of magnesium sulfate (MgSO₄ ) to healthy horses. MgSO₄ is a magnesium salt that has been used to calm horses in equestrian competition and is difficult to regulate because magnesium is an essential constituent of all mammals. Six healthy adult female horses were administered a single intravenous dose of MgSO₄ at 60 mg/kg of body weight over 5 min. Blood, urine, and cerebrospinal fluid (CSF) samples were collected, and cardiovascular parameters were monitored and echocardiograms performed at predetermined times. Noncompartmental pharmacokinetic analysis was applied to plasma concentrations of ionized magnesium (Mg²⁺ ). Objective data were analyzed using the Wilcoxon rank-sum test with p < .05 used as a determination for significance. Plasma concentrations of Mg²⁺ increased nearly fivefold, ionized calcium (Ca²⁺ ) decreased by nearly 10%, and the Ca²⁺ to Mg²⁺ ratio declined more than 3.5-fold and remained different than baseline until 24 hr (p < .05). Significant changes were seen with urinary fractional excretion of electrolytes, cardiovascular parameters, and echocardiographic measurements. No changes were detected in CSF electrolyte concentrations. The decrease in Ca²⁺ result of hypermagnesemia supports the interaction between these cations. Alterations detected in plasma electrolyte concentrations and urinary fractional excretion of electrolytes may serve as biomarkers for regulatory control for the nefarious administration of MgSO₄ .

Radio-Telemetric Assessment of Cardiac Variables and Locomotion With Experimentally Induced Hypermagnesemia in Horses Using Chronically Implanted Catheters

The objective of this study was to characterize the pharmacokinetics and pharmacodynamics of intravenous administration of magnesium sulfate to horses using a novel radio-telemetry system for physiologic signal capture. Five Horses were surgically implanted with a radio-telemetric carotid catheter. Implants were paired with a non-invasive telemetric unit which acquired a six lead ECG and 3-axis acceleration to assess activity acquired wirelessly in real-time for future analysis. Horses were exposed to a new stall environment before (baseline) and after 60 mg/kg (30 mL) of magnesium sulfate (MgSO₄), or the same volume of 0.9% saline, administered intravenously in a blinded, random crossover design. Blood for pharmacokinetics, telemetric data, and body temperature were recorded serially for 24 h. Data were analyzed across time and between treatments. Significance was set at P < 0.05. Ionized magnesium concentration (Mg²⁺) increased and the Ca²⁺ to Mg²⁺ ratio decreased and persisted for 5 h after MgSO₄ administration. Heart rate (HR) increased and mean arterial blood pressure (MAP) decreased for at least 6 h. Electrocardiogram (ECG) intervals (RR) decreased and (PR and QTc) increased in duration compared to controls indicating an increase in heart rate, and slower myocardial conduction in the MgSO₄ group. Acceleration in all planes was less in the MgSO₄ group compared to controls indicating decreased locomotion. This novel method permitted collection of physiologic signals without interference by handlers or animal restraint. An intravenous bolus of MgSO₄ produced cardiac variable changes associated with the reduction of locomotion in these horses, and in a direction that may be causal. Locomotion was decreased when horses were first introduced into a new environment which reflects the calming effect desired in sport horses. Telemetric monitoring can be used as a model to elucidate the behavior and physiologic effects of other drugs. The administration of MgSO₄ may be detected for regulatory purposes with the monitoring of Mg²⁺ and Ca²⁺ concentrations and their ratio.

Postoperative Management in Patients with Pheochromocytoma and Paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare catecholamine-secreting neuroendocrine tumors of the adrenal medulla and sympathetic/parasympathetic ganglion cells, respectively. Excessive release of catecholamines leads to episodic symptoms and signs of PPGL, which include hypertension, headache, palpitations, and diaphoresis. Intraoperatively, large amounts of catecholamines are released into the bloodstream through handling and manipulation of the tumor(s). In contrast, there could also be an abrupt decline in catecholamine levels after tumor resection. Because of such binary manifestations of PPGL, patients may develop perplexing and substantially devastating cardiovascular complications during the perioperative period. These complications include hypertension, hypotension, arrhythmias, myocardial infarction, heart failure, and cerebrovascular accident. Other complications seen in the postoperative period include fever, hypoglycemia, cortisol deficiency, urinary retention, etc. In the interest of safe patient care, such emergencies require precise diagnosis and treatment. Surgeons, anesthesiologists, and intensivists must be aware of the clinical manifestations and complications associated with a sudden increase or decrease in catecholamine levels and should work closely together to be able to provide appropriate management to minimize morbidity and mortality associated with PPGLs.

Precision Surgery for Pheochromocytomas and Paragangliomas

Since Felix Fränkel's account of pheochromocytoma in 1886, great discoveries and vast advancements in the diagnosis, genetics, anatomical and functional imaging techniques, and surgical management of pheochromcytoma and paraganglioma (P-PGL) have been made. The improved insight in the pathophysiology of P-PGL and more accurate detection methods enable physicians to tailor the treatment plan to an individual based on the genetic profile and tumor behavior. This review will cover briefly the clinical features, diagnosis, genetic mutations, and imaging modalities that are used to guide current surgical management of these rare and interesting endocrinopathies.

Anesthetic Management of Staged Bilateral Adrenalectomy for Neuroendocrine Tumors in a Heart-Lung Transplant Patient: A Case Report

Neuroendocrine tumors may rarely present after organ transplantation, including cardiac transplant. Treatment is surgical resection with careful perioperative management to optimize blood pressure and intravascular volume. We present the anesthetic management of a patient who was diagnosed with bilateral neuroendocrine tumors soon after heart-lung transplantation and underwent successful staged bilateral adrenalectomy.

Pediatric paraganglioma of the posterior mediastinum: A case report and review of literature

RATIONALE

Paraganglioma is rare in children and most pheochromocytomas originate in the adrenal gland.

PATIENT CONCERNS

The clinical characteristics, diagnosis, and managements in a 9-year-old boy who presented with vomiting and occasional headache with a blood pressure of 210/170 mm Hg was retrospectively reviewed. CT scan of the chest revealed a 7 × 5-cm-sized soft tissue mass in the left paraspinal area. Biochemical reports revealed elevated levels of serum norepinephrine, urine norepinephrine, urine dopamine, and serum neuron specific enolase.

DIAGNOSES

The immunohistochemical studies suggested that the tumor was a paraganglioma of the posterior mediastinum.

INTERVENTIONS

The patient underwent mass resection with thoracotomy. Before operation, the patient was prepared by orally administering captopril, propranolol hydrochloride, and phenoxybenzamine. Body fluid volume was also prepared by vein and mouth in 3 days.

OUTCOMES

The patient was followed up postoperatively for 1 year without recurrence.

LESSONS

We should be highly vigilant the pediatric tumor of the posterior mediastinum with vomiting and headache as the first clinical manifestation.

[Peculiarities of anesthesia for the surgical treatment of pheochromocytoma: about a case]

Nous rapportons la prise en charge d'une patiente de 37 ans, aux antécédents d'hypertension artérielle (HTA) mal suivie, adressée en consultation chirurgicale avec une symptomatologie faite de lombalgies droites, de vertiges, de céphalées, de sueurs et de palpitations. Durant l'hospitalisation, la tension artérielle (TA) oscillait entre 130/80 mm d'Hg et 190/120 mm d'Hg. Le reste de l'examen clinique ne retrouvait aucune autre anomalie. Le scanner thoraco-abdominal avait montré une masse surrénalienne de 55x45x65 mm comprimant la veine cave inférieure et la veine rénale droite. Le dosage de l'acide vanyl-mandélique urinaire (VMA) donnait un résultat de 11,8mg/24heures. Le dosage des catécholamines sanguin n'a pas été réalisé. Le diagnostic d'un phéochromocytome était retenu et l'indication opératoire était posée. En consultation d'anesthésie l'examen clinique retrouvait un bon état général, une tension artérielle (TA) à 190/120 mmHg, une auscultation cardiopulmonaire sans particularité et un critère prédictif d'intubation non difficile (Mallampati II). La patiente a bénéficiée d'une préparation préopératoire à base d'alpha-bloquants et bêta-bloquants, et d'un inhibiteur calcique. La surrénalectomie a été réalisée par laparotomie médiane. Il n'y avait pas eu d'instabilité hémodynamique lors de la mobilisation et de la résection de la tumeur. Les suites opératoires immédiates ont été simples. Elle a regagné son domicile à J7 postopératoire. Avec un recul de 3 mois, la patiente ne présentait plus de signes cliniques et ses chiffres tensionnels étaient normaux. L'anesthésie pour la chirurgie du phéochromocytome est faisable même en situation de ressources limitées. Une bonne préparation du patient permet d'éviter les complications périopératoires.

Role of vasopressin in current anesthetic practice

Arginine vasopressin (AVP), also known as antidiuretic hormone, is a peptide endogenously secreted by the posterior pituitary in response to hyperosmolar plasma or systemic hypoperfusion states. When administered intravenously, it causes an intense peripheral vasoconstriction through stimulation of V₁ receptors on the vascular smooth muscle. Patients in refractory shock associated with severe sepsis, cardiogenic or vasodilatory shock, or cardiopulmonary bypass have inappropriately low plasma levels of AVP (‘relative vasopressin deficiency’) and supersensitivity to exogenously-administered AVP. Low doses of AVP and its synthetic analog terlipressin can restore vasomotor tone in conditions that are resistant to catecholamines, with preservation of renal blood flow and urine output. They are also useful in the treatment of refractory arterial hypotension in patients chronically treated with renin-angiotensin system inhibitors, cardiac arrest, or bleeding esophageal varices. In the perioperative setting, they represent attractive adjunct vasopressors in advanced shock states that are unresponsive to conventional therapeutic strategies.

Perioperative Management of Pheochromocytoma

Pheochromocytomas are rare neuroendocrine tumors that produce and store catecholamines. Without adequate preparation, the release of excessive amounts of catecholamines, especially during anesthetic induction or during surgical removal, can produce life-threatening cardiovascular complications. This review focuses on the perioperative management of pheochromocytoma/paragangliomas, initially summarizing the clinical aspects of the disease and then highlighting the current evidence available for preoperative, intraoperative, and postoperative anesthetic management.

Perioperative Management of Severe Hypertension during Laparoscopic Surgery for Pheochromocytoma

Phaeochromocytoma is a catecholamine-secreting vascular tumour that is derived from chromaffin cell. Lethal cardiovascular complications, such as serious hypertension, myocardial infarction and aortic dissection, may occur because of uncontrolled catecholamine release. Each stage of anaesthesia management has vital importance because of this destructive catecholamine secretion that may occur during induction, perioperative stage and surgical manipulation. In this study, we report regarding the preoperative preparation and severe, persistent hypertension attack management with a combination of α-adrenergic blockade, β-adrenergic blockade, sodium nitroprusside and remifentanil in a patient who underwent laparoscopic surgery for phaeochromocytoma.

MANAGEMENT OF CATECHOLAMINE-SECRETING TUMORS IN PREGNANCY: A REVIEW

OBJECTIVE

Catecholamine-secreting tumors (pheochromocytomas and paragangliomas) presenting during pregnancy are extremely rare, but they can be fatal to both mother and fetus. Recent discoveries in the genetic background of these tumors are expected to address an increasing number of at-risk women to prenatal diagnosis.

METHODS

The literature was reviewed in order to provide clinicians with a practical and updated guide on how to manage this life-threatening condition.

RESULTS

The clinical presentation of catecholamine-secreting tumors can be deceptive and mimic common disorders of pregnancy. Silent catecholamine-secreting tumors can become evident during pregnancy, and hypertension cannot be considered a hallmark for this condition: some women may be normotensive or develop orthostatic hypotension. Biochemical screening includes measurement of plasma free metanephrines or urinary fractioned metanephrines. Measurement of catecholamines, dopamine, and methoxytyramine can provide further information on tumor biology, location, and prognosis. Diagnostic imaging is limited, and medical treatment requires a cautious balance between hemodynamic control and effects on the fetoplacental unit. Several genes have been associated with syndromes including catecholamine-secreting tumors, and positive genetic testing can correlate with tumor behavior. Timing and modalities for tumor removal and delivery, including anesthetic management, depend on gestational age, maternal and fetal wellbeing, control of catecholamine excess, suspicion of multiple or malignant disease, and surgical accessibility to the tumor.

CONCLUSION

A timely diagnosis and a multidisciplinary approach are the keys to improve pregnancy outcomes in patients with a catecholamine-secreting tumor; each case should be managed in a tertiary referral center.

Magnesium sulphate and (123)I-MIBG in pheochromocytoma: Two useful techniques for a complicated disease

Pheochromocytoma is a tumour of the chromaffin tissue. It may, through catecholamine release, have deleterious effects on myocardial structure. A 48-year-old woman with a history of hypertension and type II diabetes mellitus (ASA II) was diagnosed of pheochromocytoma-induced myocarditis, which caused severe cardiogenic shock, with an ejection fraction of 20%. Extreme blood pressure swings required aggressive therapy with vasoactive drugs (norepinephrine and dopamine) and an intra-aortic balloon pump, despite which severe haemodynamic instability persisted. Finally, the use of magnesium sulphate allowed for cardiovascular stabilization and weaning off vasoactive drugs prior to surgery. (123)I-metaiodobenzylguanidine scintigraphy helps not only to functionally confirm tumour tissue, but also to assess severity and prognosis of cardiac failure. Prognosis of pheochromocytoma-induced heart failure can be very poor. The use of these two well-known and relatively simple 'tools' for treatment and prognosis is a helpful option to keep in mind.

Single-Session CT-Guided Percutaneous Microwave Ablation of Bilateral Adrenal Gland Hyperplasia Due to Ectopic ACTH Syndrome

Bilateral adrenalectomy is currently the only available treatment for adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (ectopic ACTH syndrome) that is refractory to pharmacologic therapy. We describe two patients with refractory ectopic ACTH syndrome who were treated with CT-guided percutaneous microwave ablation of both hyperplastic adrenal glands in a single session: O ne was not a surgical candidate, and the other had undergone unsuccessful surgery. Following the procedure, both patients achieved substantial decreases in serum cortisol, symptomatic improvement, and decreased anti-hypertensive medication requirements.

Anesthetic management for resection of para-aortic paraganglioma and unexpected aortic resection: A case report

Paragangliomas account for 15-20% of pheochromocytomas derived from chromaffin cells and secretes catecholamines. It has a high mortality rate due to hypertension and challenging anesthetic management. The present report is of a case of the successful management of paraganglioma resection with unexpected aortic resection. The patient presented for paraganglioma resection. The blood pressure (BP) was well controlled with α blockade followed by β blockade prior to surgery. The patient was under general anesthesia, with multiple intravenous lines, catheters and an arterial line. Induction was achieved by the administration of narcotic and volatile agents. During the procedure, the aorta was found to require resection in order to complete the tumor resection. The BP changed markedly with clamping and unclamping, tumor vein ligation and tumor resection. The increased BP due to catecholamine release and unclamping was controlled with phentolamine, nitroprusside, esmolol and labetolol. Drops in BP due to tumor vein ligation and clamping were managed with norepinephrine and vasopressin. With close communication and monitoring, the surgery on the patient was successfully completed and the patient was discharged days later in a hemodynamically stable condition. The diagnosis was further confirmed by pathology. This was a challenging case of paraganglioma resection with unexpected aortic resection. The success achieved suggests that the resection of paraganglioma and an aortic segment requires delicate anesthetic management. The key are α blockade and β blockade as necessary to control BP pre-operatively, frequent communication between the anesthesiologist and surgeons, intra-operative intervention in excess catecholamine release with phentolamine, nitroprusside and labetalol prior to tumor removal, and vasopressin for catecholamine deficiency when clamping or subsequent to tumor removal. It is a delicately orchestrated process requiring team work.

Phaeochromocytoma [corrected] crisis

Phaeochromocytoma [corrected] crisis is an endocrine emergency associated with significant mortality. There is little published guidance on the management of phaeochromocytoma [corrected] crisis. This clinical practice update summarizes the relevant published literature, including a detailed review of cases published in the past 5 years, and a proposed classification system. We review the recommended management of phaeochromocytoma [corrected] crisis including the use of alpha-blockade, which is strongly associated with survival of a crisis. Mechanical circulatory supportive therapy (including intra-aortic balloon pump or extra-corporeal membrane oxygenation) is strongly recommended for patients with sustained hypotension. Surgical intervention should be deferred until medical stabilization is achieved.

Anesthetic emergencies in oral surgery: malignant hyperthermia, endocrinopathy, and neurologic events

Despite the impressive safety of office-based anesthesia, serious emergencies still occur. Early and appropriate treatment is likely to improve outcomes. This article discusses selected emergencies with backgrounds and rationale for emergent treatment.

Endocrine emergencies in dogs and cats

Success in treatment of endocrine emergencies is contingent on early recognition and treatment. Many endocrine diseases presenting emergently have nonspecific signs and symptoms. In addition, these endocrine crises are often precipitated by concurrent disease, further making early identification difficult. This article concentrates on recognition and emergency management of the most common endocrine crises in dogs and cats.