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Published on January 12, 2009

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Anesthetic considerations in patients with mediastinal tumors : Anesthetic considerations in patients with mediastinal tumors R1??? History : History Name: ? * ? Gender: female Age: 4 y/o Date of birth: 2000/08/30 G1P1, full term, BBW: 2750g Slide 3: 2002/09: decreased activity and intermittent noisy respiratory sound presented at MKMH: chest CT revealed a large heterogeneous mass over right lung field with much pleural effusion. She was transferred to our hospital: Saturation was around 94~96%. CXR showed whiteout over right lung field with trachea deviated to left side Tumor biopsy with port-A insertion was done on 2002/09/27 with mildly improved respiratory distress. Pathology of the mediastinal mass reported sarcoma, unclassified. Chemotherapy was planned, but family refused. She was then AAD on 10/08 under respiratory distress (SpO2 sound 90-95% with tachypnea RR around 35/min) Slide 4: Cough persisted after discharge and some traditional medication had prescribed. Poor activity, poor appetite, dyspnea, orthopnea, and much oral secretions developed She was then brought to our ER on 10/28 where chest CT revealed huge mediastinal mass occupying the whole right lung field with mediastinal shift (main airway and heart was compressed) Due to high risk of cardiopulmonary compromise, emergent-debulking surgery (nearly total removal) was done in the night of 2002/10/28. Slide 5: The right lung expanded and heart, trachea returned to normal position after operation. The pathological diagnosis was infantile fibrosarcoma. She was discharged on 11/18 under stable clinical condition. Slide 6: Follow up chest CT (2002.12) showed extensive mass lesions within the right upper, lower lung fields, right thoracic cage. Under the impression of tumor recurrence, adjuvant chemotherapy was started. Totally 4 courses of VAC were given. Slide 7: CT on 2003/07/02 showed a lobulated mass lesion at lateral aspect of right upper thorax with bone destruction of lateral aspect of right 2nd rib, which showed increased size, compared with previous CT study in 2003.4. Right lower posterior pleural thickening with enlarging focal nodular lesion was also noticed. Slide 8: The surgery was performed smoothly on 2003/07/04. A tumor mass of 3x1 cm was excised from the 5th rib area. A patch of tumor in the inner chest wall surface extending from the subclavian area to 5th rib was also removed. Furthermore, a 0.2x0.2 cm tumor was removed from the inferior posterior part of her chest wall. There was also one tumor removed from dorsal side of her scapula. She then received VIP(vp-16 + ifosfomide + cisplatin) on 7/17-24 Slide 9: Compared with pre-op films, two new (enlarged) lesions were seen on right posterior pleura, 1cm below carina and around right inferior pulmonary trunk level. Disease progression was highly suspected. In the surgical pathologic conference on 7/22, pathologist, pediatric surgeon and radiologist revised the diagnosis as malignant peripheral nerve sheath tumor (MPNST) based on immunocytochemical stain. Slide 10: After searching the literature about MPNST. This tumor is generally considered to be chemo-resistent. What seems to improve the diagnosis is complete surgical resection and adjuvant radiation therapy Her family hesitate about radiotherapy. She continued to receive several courses of chemotherapy during 2003/08-2003/10. Slide 11: 2003/11: A 1x1 cm firm mass over left scapular region was found 2003/12: a rapid growing mass above the previous one appeared. It grew to 6x6 cm in 1 month with pain and itchness 2004/01: she always lied on the bed with right side down and unwilling to sit or stand , fever up to 38.2, Due to poor activity and r/o airway obstruction, she is admitted today for further evaluation Slide 12: Chest CT was done on 1/20 that revealed huge tumor mass involved right side hemithorax, scapula, shoulder. Right lung almost total collapsed and mediastinum was compressed to left side. Due to mass effect of tumor and its rapid growing, pediatric durgeon VS.??? was consulted and emergent debulking surgery was done in the night of 1/20. Extubation was done on 1/26 and she was transferred to general ward on 1/27. Slide 13: Reevaluation of tumor mass of CT on 2/3 showed heterogeneous mass lesion occupy in the right side upper thorax with extension to the thoracic cage and right side axillary portion with surrounding bone destruction. This tumor also invaded into the right side scapullar region and result in partial atelectasis of the right lung. Due to the rapid growing and ineffective result of chemotherapy, radiotherapeutics was consulted for treatment plan. Continue chemotherapy Fever? tumor fever was more likely Slide 14: Follow up CT and MRI showed bulky mass lesion at the right lower neck, right chest wall, right thoracic cavity  on 2003/02-03 CVS and chest surgeons were consulted for the possibility of compromising of great vessels, trachea, esophagus, and heart. Progressive dyspnea was note on 2004/04 Episodes of desaturation to SpO2 around 80% noted since 2004/04/09 Slide 15: She was transferred to PICU on 2003/04/11 due to impending respiratory failure. Emergent debuking surgery was arranged on 2004/04/12. Slide 16: Induction with ketamine and sevoflurane Intubation with 6.0 without cuff fixed at 16 cm Paralysis with Esmeron with controlled positive ventilation Supine position CO2 retention >110 mmHg was noted, peak airway pressure was high ( > 40 cm H2O) Fiberscope was performed: external compression was noted around 16-17cm The endotracheal tube was then fixed at 20cm for one lung ventilation CO2 was washed out smoothly and quickly Then the endotracheal tube was fixed at 18cm just above the carina Maintenance was uneventfulh Slide 18: Endotracheal tube was inplace with ventilator low setting in PICU PS surgery for extrathoracic debulking was planned on 4/16. Slide 19: After induction with pentothal, nimbex, and fentanyl, CO2 retention (around 70-80 mmHg) with high peak airway pressure was noted. Fiberscope was performed: no significant obstruction Desaturation to SpO2 around 70% was noted after left decubitus positioning Left breathing sound: clear, chest wall expansion(+) 100% O2 supple, PEEP 5 cm H2O, change position to supine? right decubitus: no improve Spontaneous breathing? SpO2 returned to 100% Slide 20: The surgery was DC. Extubation was performed on 4/18 by herself. After extubation,she still need some O2 supplement. Discussion : Discussion What is MPNST? Anesthetic management of mediastinum tumor What happened to this patient? Malignant peripheral nerve sheath tumor (MPNST) : Malignant peripheral nerve sheath tumor (MPNST) Derived from Schwann cells or pluripotent cells of the neural crest The most common malignant mesenchymal tumors of soft tissue 4% of patients with neurofibromatosis type I developed MPSNT General population: 0.001% Classification based on gross anatomy: spinal root, peripheral nerve, nerve plexus, no nerve of origin Slide 23: Most frequent initial s/s: painless mass Diagnosis is usually delayed ( 5.5 months)? MRI, tissue proved Wide surgical excision is the treatment of choice and prolongs survival. Adjuvant or neoadjuvant radiation therapy decreased the hazard of death of disease. Chemotherapy is of unproven benefit: more likely to have tumor characteristics predictive of an unfavorable outcome. Local recurrence rate following gross total resection: 32-65% Anesthetic consideration : Anesthetic consideration Compression of the tracheobronchial tree Compression of the pulmonary artery and heart Superior vena cava syndrome Compression of the tracheobronchial tree : Compression of the tracheobronchial tree Pathophysiology Anterosuperior mediastinum: thymus, lower trachea, upper esophagus, the arch of aorta and branches, SVC, azygos veins Adults: thymic neoplasms, lymphoma, germ-cell tumor Children: neurogenic tumors, germ-cell tumors Slide 26: Obstruction of major airways by a tumor is usually life-threatening because the obstruction usually occurs around the bifurcation of the tracheabronchial tree and is therefore distal to the endotracheal tube. It may be that loss of chest wall tone and the distending forces of active inspiration after administration of muscle relaxants release extrinsic support of a critically narrowed airway intubation in the presence of distortion or compression of the trachea may cause complete obstruction if the orifice of the tube impinges on the tracheal wall or if the lumen of the tube is occluded where it passes a narrowed section or turns a sharp angle Risks of GA : Risks of GA lung volume is reduced to as little as 500–1500 ml under general anaesthesia; relaxation of bronchial smooth muscle leads to greater compressibility of the airway from the overlying mass; the loss of spontaneous diaphragmatic movement with paralysis induced by muscle relaxants reduces the normal transpleural pressure gradient which dilates the airway. This decreases the calibre of the airways and enhances the effect of extrinsic compression. Slide 28: Pre-op evaluation Clinical S/S CXR CT Pulmonary function test Slide 29: Clinical S/S: cough, DOE, orthopnea, stridor, cyanosis, wheeze, ronchi Even asymptomatic patents have developed life-threatening complications at induction of anesthesia. CXR : CXR PA position: measurement of the trachea diameter at the level of the clavicals, may over estimate though Lateral view: show the degree of compression of the trachea in an AP direction CT : CT Identify the location of the mass Delineate its margins Define its relationship to adjacent structures Determine the extent of tracheal or vascular compression CT : CT Cross-section area A1: narrowest area; A2: an area without extrinsic compression or endoluminal involvement A =p* d1/2 * d2/2 Tracheal compression (%)= 100- (A1/A2 * 100) Tracheal compression > 50%: high rate of total airway obstruction during GA, sevenfold increase in the risk of post-op respiratory complication GA should be avoided in children with less than 66% (50%?)of normal tracheal area Pulmonary function test : Pulmonary function test FEV1, FVC, PEFR, flow volume curve Obstructive: FEV1<80%, FEV1/FVC <70% Restrictive: TLC < 85%, FVC < 80%, FEV1/FVC > 70% Slide 34: PEFR <40% : > 10-fold increase in risk of periop complication A combination of obstructive and restrictive patterns ? high rate of post-op respiratory complication Flow volume loop : Flow volume loop Supine, upright, and lateral position Variable extrathoracic obstruction: expiration is preserved; inspiration impaired Variable intrathoracic obstruction: expiration impaired; inspiration is preserved Fixed: both impaired Rarely useful; not offer any additive benefit in predicting periop complications Peri-op management : Peri-op management In pediatric patients: volatile agent induction is usually the technique of choice In adult: awake fiberotic technique with topical anesthes Spontaneous breathing, avoid muscle relaxants Change positions rapidly Rigid ventilating bronchoscope Cardiopulmonary bypass Patients should be allowed to breath spontaneously : Patients should be allowed to breath spontaneously In paralyzed patients:-Positive pressure ventilation induced dynamic hyperinflation ? high transbronchial pressure ? worsen obstruction ? decrease expiratory flow (manual compression of chest wall )-large changes in intrathoracic pressure? promote collapse of a weakened tracheobronchial tree Compression of the pulmonary artery and heart : Compression of the pulmonary artery and heart Very rare: the pulmonary trunk is more or less protected by the aortic arch and trachealcronchial tree (Miller) More common than realized: 1. In the supine position, the right ventricular outflow tract is the most superior cardiac structure 2. the right heart is a low-pressure chamber, and is more sensitive to compression than the high-pressure ascending aorta. The right heart usually can compensate for moderate increases in pulmonary afterload. 3. Adverse position, induction of anesthesia, hypovolemia, and reduced cardiac contractility, however, may attenuate compensatory mechanisms. Clinical S/S are not apparent; mimic tracheal or bronchial obstruction Slide 39: mediastinal CT or MR imaging and ECG, should identify at-risk patients. Patients who develop syncope during Valsalva maneuver are believed to be particularly at risk, because this situation suggests significant vascular encroachment Peri-op management : Peri-op management Patients with an anterior mediastinal mass may develop severe hemodynamic compromise caused by compression of the heart and great vessels after induction of anesthesia, institution of positive pressure ventilation, or supine positioning. Positive pressure ventilation can cause dynamic hyperinflation autopositive end-expiratory pressure (auto-PEEP) because of expiratory gas flow obstruction. With sufficient elevation of intrathoracic pressure, the gradient for venous return is reduced, and right ventricular pressures are reduced, worsening the extent of vascular obstruction. Slide 41: Intravascular volume loading Prompt use of inotropics and vasoconstrictors to maintain cardiac output Be acutely aware of the position of the mass in relation to the cardiovascular structures because urgent repositioning of the patient may be required to relieve severe hypotension Maintain venous return Maintain spontaneous breathing Cardiopulmonary bypass ECMO Superior vena cava syndrome : Superior vena cava syndrome Mechanically obstruction of the SVC Edema of the head, neck, and upper extremities Respiratory S/S, epidural vein enlargement Catheterization on lower extremities What happened to this patient? : What happened to this patient? CO2 retention, expiration impaired - airway compression- paralyzed with positive pressure ventilation High airway pressure Desaturation- inadequate ventilation: positioning? - increased shunting: inhalation anesthetics reduced hypoxic pulmonary vasoconstriction - lung collapse: high airway pressure Thereafter … : Thereafter … The patient was extubated by herself on 4/18 evening Still need O2 support She was transferred to general ward for ongoing chemotherapy on 4/19 She was transferred back to ICU on 4/24 due to impending respiratory failure Slide 46: We were consulted for intubation on 4/24 night O2 mask, SpO2 100%, respiratory with effort, right decubetus position Ketamine 20mg was given, SCC 10 mg Intubated with 5.5 with cuff fixed at 18cm Ventilator: low setting She is waiting for… ( further treatment???) References : References Anesthesia, 5th edition, Ronald D. Miller ANESTHESIA FOR PATIENTS WITH A MEDIASTINAL MASS, Anesthesiology Clinics of North America,Volume 19 • Number 3 • September 2001 Surgical rescue for life-threatening hypoxemia caused by a mediastinal tumor, Ann Thorac Surg, 1999, 68:2324-6 Anterior mediastinal masses: an anesthetic challenge, anesthesia, 1999, 54:670-682 General anesthesia prior to treatment of anterior mediastinal masses in pediatric cancer patients. Anesthesiology 72:991-995, 1990 Have a nice day! : Have a nice day! ??????: ?????,???????????????:????,????????????,??????????,???????,???????????????? --???,”?????”,???? ?Smile anyway? Keep walking. Keep smiling.®

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