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Neuromascular Council Consensus Statement

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  • 1. NEUROMUSCULAR COUNCILNEUROMUSCULAR COUNCIL CONSENSUS STATEMENTCONSENSUS STATEMENT THYMECTOMY FORTHYMECTOMY FOR NONTHYMOMATOUS AUTOIMMUNENONTHYMOMATOUS AUTOIMMUNE MYASTHENIA GRAVIS PATIENTSMYASTHENIA GRAVIS PATIENTS
  • 2. IntroductionIntroduction
  • 3. Through the years many neurologists have favored theThrough the years many neurologists have favored the use of thymectomy in the management of patients withuse of thymectomy in the management of patients with nonthymomatous autoimmune myasthenia gravis (MG).nonthymomatous autoimmune myasthenia gravis (MG). This wide acceptance is based largely upon case series andThis wide acceptance is based largely upon case series and retrospective studies which have suggested thatretrospective studies which have suggested that thymectomy may be beneficial. However, many of thesethymectomy may be beneficial. However, many of these studies have shown variable results. Moreover, the absencestudies have shown variable results. Moreover, the absence of controlled, prospective trials casts some doubt regardingof controlled, prospective trials casts some doubt regarding effectiveness of the procedure in this group of patients.effectiveness of the procedure in this group of patients. Thus, until the results of an ongoing international,Thus, until the results of an ongoing international, prospective, single blind randomized trial controlling forprospective, single blind randomized trial controlling for medical therapy become available, the use of thymectomymedical therapy become available, the use of thymectomy in this situation remains controversial.in this situation remains controversial.
  • 4. In the local medical centers where thymectomy isIn the local medical centers where thymectomy is being performed, no standard guidelines in the selection ofbeing performed, no standard guidelines in the selection of patients and the pre- and post-operative management havepatients and the pre- and post-operative management have been created. This necessitates the formulation of suchbeen created. This necessitates the formulation of such guidelines.guidelines.
  • 5. ObjectivesObjectives
  • 6. General ObjectiveGeneral Objective The Neuromuscular Council of the PhilippineThe Neuromuscular Council of the Philippine Neurological Association aims to improve outcomesNeurological Association aims to improve outcomes for MG patients by providing the initial framework forfor MG patients by providing the initial framework for decision-making for neurologists with regard to thedecision-making for neurologists with regard to the patient diagnosed with nonthymomatous autoimmunepatient diagnosed with nonthymomatous autoimmune MG who is a candidate for thymectomy.MG who is a candidate for thymectomy.
  • 7. Specific ObjectiveSpecific Objective To develop a combined evidence- and consensus-To develop a combined evidence- and consensus- based practice parameter to guide neurologists inbased practice parameter to guide neurologists in managing patients diagnosed with nonthymomatousmanaging patients diagnosed with nonthymomatous autoimmune myasthenia gravis who can be candidatesautoimmune myasthenia gravis who can be candidates for thymectomy.for thymectomy.
  • 8. MethodologyMethodology
  • 9. Group CompositionGroup Composition The working group is composed of the members ofThe working group is composed of the members of the Neuromuscular Council of the PNA.the Neuromuscular Council of the PNA. Dr. Lina Renales Dr. Rosalia Teleg Dr. Valmarie Estrada Dr. Darwin Dasig Dr. Emmanuel Eduardo Dr. Alejandro Diaz Dr. Raymond Rosales Dr. Jose Paciano Reyes Dr. Ludwig Damian
  • 10. Consensus ProcessConsensus Process The initial draft of the consensus statement was aThe initial draft of the consensus statement was a synthesis of the survey, identification of the key clinicalsynthesis of the survey, identification of the key clinical issues, output of literature search using Medline and theissues, output of literature search using Medline and the local registry and academic deliberation by the workinglocal registry and academic deliberation by the working group over the identified key issues. Deliberationgroup over the identified key issues. Deliberation included appraisal of the literature in terms of validityincluded appraisal of the literature in terms of validity and applicability, preparation of evidence-basedand applicability, preparation of evidence-based summaries and development of judgments bysummaries and development of judgments by consensus. This is to be followed by presentation of theconsensus. This is to be followed by presentation of the statements in a public forum composed of the PNAstatements in a public forum composed of the PNA fellows.fellows.
  • 11. Disclaimer:Disclaimer: The assessment and recommendations providedThe assessment and recommendations provided herein represent the best professional judgment of theherein represent the best professional judgment of the working group at this time, based on research dataworking group at this time, based on research data gathered and on expertise currently available. Thegathered and on expertise currently available. The conclusions and recommendations will be regularlyconclusions and recommendations will be regularly assessed as new information becomes available. Theassessed as new information becomes available. The consensus statement is intended to be an educationalconsensus statement is intended to be an educational guideline and is therefore neither rigidly prescriptive norguideline and is therefore neither rigidly prescriptive nor restrictive.restrictive.
  • 12. Key Clinical IssuesKey Clinical Issues AddressedAddressed
  • 13. 1.1. Should thymectomy for nonthymomatous myastheniaShould thymectomy for nonthymomatous myasthenia gravis be recommended?gravis be recommended? 2.2. What is the clinical profile of nonthymomatousWhat is the clinical profile of nonthymomatous autoimmune MG patients likely to benefit fromautoimmune MG patients likely to benefit from thymectomy?thymectomy? 3.3. When is the ideal time to perform thymectomy?When is the ideal time to perform thymectomy?
  • 14. 4.4. What is the preferred thymectomy technique to use?What is the preferred thymectomy technique to use? 5.5. What is the recommended pre-operativeWhat is the recommended pre-operative management?management? 6.6. What is the recommended post-operativeWhat is the recommended post-operative management?management?
  • 15. Consensus ProperConsensus Proper
  • 16. QUESTION 1:QUESTION 1: Should thymectomy for nonthymomatousShould thymectomy for nonthymomatous autoimmune myasthenia gravis beautoimmune myasthenia gravis be recommended?recommended?
  • 17. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation For patients with nonthymomatous autoimmuneFor patients with nonthymomatous autoimmune MG, thymectomy is recommended as anMG, thymectomy is recommended as an optionoption toto increase the probability of remission or improvementincrease the probability of remission or improvement (Level 2 evidence).(Level 2 evidence). Research RecommendationResearch Recommendation There is a need to conduct a well-designed,There is a need to conduct a well-designed, prospective, controlled study to evaluate clinicalprospective, controlled study to evaluate clinical effectiveness of thymectomy in nonthymomatous,effectiveness of thymectomy in nonthymomatous, autoimmune myasthenia gravis patients that utilizeautoimmune myasthenia gravis patients that utilize comparison with standardized medical therapy and well-comparison with standardized medical therapy and well- defined evaluation standards.defined evaluation standards.
  • 18. B. Summary of EvidenceB. Summary of Evidence To address the uncertainty of the usefulness ofTo address the uncertainty of the usefulness of thymectomy in nonthymomatous autoimmune MGthymectomy in nonthymomatous autoimmune MG because of the lack of prospective and controlledbecause of the lack of prospective and controlled studies, the working group utilized the systematic reviewstudies, the working group utilized the systematic review done by the American Academy of Neurology.1 Theirdone by the American Academy of Neurology.1 Their review of 28 articles (Class II evidence 2) publishedreview of 28 articles (Class II evidence 2) published from 1953 to 1998 describing outcome in 21 MGfrom 1953 to 1998 describing outcome in 21 MG cohorts revealed the following observations:cohorts revealed the following observations:
  • 19. 1.1. Positive associations in most studies betweenPositive associations in most studies between thymectomy and MG remission and improvementthymectomy and MG remission and improvement with median rates of 2.1 for medication-freewith median rates of 2.1 for medication-free remission, 1.6 for asymptomatic group and 1.7 forremission, 1.6 for asymptomatic group and 1.7 for improvement;improvement; 2.2. Confounding differences in baseline characteristics ofConfounding differences in baseline characteristics of prognostic importance between thymectomy andprognostic importance between thymectomy and nonthymectomy groups in all studies;nonthymectomy groups in all studies;
  • 20. 3.3. Persistent positive associations between thymectomyPersistent positive associations between thymectomy and improved outcomes after controlling for singleand improved outcomes after controlling for single confounding variables such as age, gender andconfounding variables such as age, gender and severity of MG;severity of MG; 4.4. Conflicting associations between thymectomy andConflicting associations between thymectomy and improved MG outcomes in studies controlling forimproved MG outcomes in studies controlling for multiple confounding variables simultaneously.multiple confounding variables simultaneously.
  • 21. They concluded that it cannot be determined fromThey concluded that it cannot be determined from available studies whether the observed associationavailable studies whether the observed association between thymectomy and improved MG outcome wasbetween thymectomy and improved MG outcome was a result of thymectomy benefit or was merely a result ofa result of thymectomy benefit or was merely a result of multiple differences in baseline characteristics. Thus,multiple differences in baseline characteristics. Thus, the benefit of thymectomy in nonthymomatousthe benefit of thymectomy in nonthymomatous autoimmune MG has not been establishedautoimmune MG has not been established conclusively.conclusively.
  • 22. QUESTION 2:QUESTION 2: What is the clinical profile of nonthymomatousWhat is the clinical profile of nonthymomatous autoimmune MG patients most likely to benefitautoimmune MG patients most likely to benefit from thymectomy?from thymectomy?
  • 23. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation The candidate most likely to benefit is the patientThe candidate most likely to benefit is the patient with all of the following attributes (Level 2 evidence):with all of the following attributes (Level 2 evidence):  generalized MGgeneralized MG  age between puberty and 60 years andage between puberty and 60 years and  positive titers for anti-Acetylcholine Receptorpositive titers for anti-Acetylcholine Receptor Antibody (anti-AChR Ab) when applicableAntibody (anti-AChR Ab) when applicable  female genderfemale gender
  • 24. Research RecommendationResearch Recommendation There is a need to conduct a well-designedThere is a need to conduct a well-designed prospective, controlled study to evaluate clinicalprospective, controlled study to evaluate clinical outcome after thymectomy with respect to the diseaseoutcome after thymectomy with respect to the disease variables (e.g. grade or severity of the illness, age of thevariables (e.g. grade or severity of the illness, age of the patient, gender, duration of the disease, etc.), treatingpatient, gender, duration of the disease, etc.), treating these variables singly or in combination.these variables singly or in combination.
  • 25. B. Summary of EvidenceB. Summary of Evidence 1.1. GenderGender Women have been reported to have a better outcome thanWomen have been reported to have a better outcome than men after thymectomymen after thymectomy 2.2. AgeAge  There is general consensus that patients with generalized MGThere is general consensus that patients with generalized MG between puberty and 60 years will benefit from thymectomy.between puberty and 60 years will benefit from thymectomy.  Most MG experts advocate cutoff ages ranging between 50 toMost MG experts advocate cutoff ages ranging between 50 to 70 years with median at 60 years.70 years with median at 60 years.  Thymectomy has been performed with favorable results inThymectomy has been performed with favorable results in childhood. Procedure, however, remains controversial inchildhood. Procedure, however, remains controversial in younger children with ages ranging from 1 year to puberty.younger children with ages ranging from 1 year to puberty.
  • 26. 3.3. Clinical SeverityClinical Severity  Patient subgroup analysis in one studyPatient subgroup analysis in one study indicated that onlyindicated that only those patients with MG with moderate weakness or greaterthose patients with MG with moderate weakness or greater (Osserman 2B3 / MGFNA4 ) showed significant(Osserman 2B3 / MGFNA4 ) showed significant improvement after thymectomy compared with controlimprovement after thymectomy compared with control subjects. Results, however, were confounded by baselinesubjects. Results, however, were confounded by baseline patient differences across groups.patient differences across groups.  The studies reviewed did not include patients with pure ocularThe studies reviewed did not include patients with pure ocular MG.MG.  Severe patients who underwent thymectomy had betterSevere patients who underwent thymectomy had better prognosis compared with severe patients who did not.prognosis compared with severe patients who did not.
  • 27. 4.4. Duration of DiseaseDuration of Disease No data have been gathered as yet regarding measurement ofNo data have been gathered as yet regarding measurement of outcome after controlling for single confounding variable likeoutcome after controlling for single confounding variable like duration of disease (whether within 1-2 years from onset orduration of disease (whether within 1-2 years from onset or beyond 2 years from onset).beyond 2 years from onset). No conclusive data likewise are available associating improvedNo conclusive data likewise are available associating improved MG outcome with thymectomy after controlling for multipleMG outcome with thymectomy after controlling for multiple confounding variables.confounding variables.
  • 28. QUESTION 3:QUESTION 3: When is the ideal time to performWhen is the ideal time to perform thymectomy?thymectomy?
  • 29. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation Thymectomy is best performed within 1 to 2Thymectomy is best performed within 1 to 2 years from the time of diagnosisyears from the time of diagnosis provided thatprovided that thethe patient has achieved:patient has achieved:  optimal muscle strength andoptimal muscle strength and  optimal medical conditionoptimal medical condition  adequate cardio-pulmonary functions (Level 2adequate cardio-pulmonary functions (Level 2 evidence)evidence)
  • 30. Research RecommendationResearch Recommendation There is a need to conduct a well-designedThere is a need to conduct a well-designed prospective, controlled study to evaluate clinicalprospective, controlled study to evaluate clinical outcome after thymectomy with respect to the timingoutcome after thymectomy with respect to the timing of surgery.of surgery.
  • 31. B. Summary of EvidenceB. Summary of Evidence Some authors suggested that benefits fromSome authors suggested that benefits from thymectomy were achieved more readily the earlier thethymectomy were achieved more readily the earlier the surgery was done, with larger remission rates per unitsurgery was done, with larger remission rates per unit time (Class III evidence)time (Class III evidence).. However, it has beenHowever, it has been postulated that this may be solely due to non-linear ratepostulated that this may be solely due to non-linear rate at which MG patients achieve remission after diagnosis.at which MG patients achieve remission after diagnosis. This means that for a given duration of time, MGThis means that for a given duration of time, MG patients are more likely to remit earlier than later.patients are more likely to remit earlier than later.
  • 32. QUESTION 4:QUESTION 4: What is the preferred thymectomyWhat is the preferred thymectomy technique to use?technique to use?
  • 33. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation Properly performed total thymectomy using theProperly performed total thymectomy using the Extended Transsternal Approach may provide theExtended Transsternal Approach may provide the greatest resection with low morbidity and less risk forgreatest resection with low morbidity and less risk for recurrent laryngeal nerve injury (Level 2 evidence).recurrent laryngeal nerve injury (Level 2 evidence). Research RecommendationResearch Recommendation There is a need to conduct a well-designedThere is a need to conduct a well-designed prospective, controlled study to evaluate clinical outcomeprospective, controlled study to evaluate clinical outcome after thymectomy with respect to the differentafter thymectomy with respect to the different thymectomy technique.thymectomy technique.
  • 34. B. Summary of EvidenceB. Summary of Evidence The report of the Quality Standards Committee of theThe report of the Quality Standards Committee of the American Academy of Neurology1 concluded that theAmerican Academy of Neurology1 concluded that the outcome comparisons between uncontrolled studies do notoutcome comparisons between uncontrolled studies do not provide conclusive evidence of the superiority of oneprovide conclusive evidence of the superiority of one technique over another. This was due to the numeroustechnique over another. This was due to the numerous confounding differences in patients’ baseline characteristicsconfounding differences in patients’ baseline characteristics and new confounders (institutional, geographic andand new confounders (institutional, geographic and historical differences).historical differences).
  • 35. Likewise, controlled trials reviewed failed to provideLikewise, controlled trials reviewed failed to provide convincing evidences that one technique was superior,convincing evidences that one technique was superior, again due to the confounding differences andagain due to the confounding differences and inconsistent results. Moreover, operative techniquesinconsistent results. Moreover, operative techniques employed were either not identified or limited toemployed were either not identified or limited to standard transsternal and basic transcervical thymectomy.standard transsternal and basic transcervical thymectomy.
  • 36. The review of the retrospective studies3 that wasThe review of the retrospective studies3 that was published after the AAN Guidelines publication concludedpublished after the AAN Guidelines publication concluded that the studies had conflicting results and had manythat the studies had conflicting results and had many confounding variables such as patient population,confounding variables such as patient population, accompanying therapy, details of evaluation, extremeaccompanying therapy, details of evaluation, extreme variability and unpredictability of MG, variability ofvariability and unpredictability of MG, variability of selection of patients for thymectomy andselection of patients for thymectomy and immunesuppressives drugs after surgery. The need forimmunesuppressives drugs after surgery. The need for properly designed prospective trials or a non-randomizedproperly designed prospective trials or a non-randomized prospective study of two or more techniques remains.prospective study of two or more techniques remains.
  • 37. In a separate article4In a separate article4 ,,Jaretzski had written that theJaretzski had written that the more complete the thymic resection, the better themore complete the thymic resection, the better the outcome.outcome. A retrospective trial comparing the late results ofA retrospective trial comparing the late results of basic transsternal and extended transsternalbasic transsternal and extended transsternal thymectomies5thymectomies5 revealed that complete remission ratesrevealed that complete remission rates were significantly higher in the extended group at 1, 2, 3were significantly higher in the extended group at 1, 2, 3 and 4 years follow-up (Level 2 evidence). Negative resultsand 4 years follow-up (Level 2 evidence). Negative results (no improvement, deterioration or death from MG) were(no improvement, deterioration or death from MG) were significantly lower in the extended thymectomy group.significantly lower in the extended thymectomy group. The difference was postulated to be due to the removal ofThe difference was postulated to be due to the removal of ectopic foci of thymic tissue from the neck andectopic foci of thymic tissue from the neck and mediastinum.mediastinum.
  • 38. Mantegazza et.al. performed a prospective,Mantegazza et.al. performed a prospective, uncontrolled trial comparing video-assisted thoracoscopicuncontrolled trial comparing video-assisted thoracoscopic extended thymectomy (VATET) and T3-B operativeextended thymectomy (VATET) and T3-B operative techniques6techniques6 and concluded that VATET seems to beand concluded that VATET seems to be effective in inducing complete stable remission similar toeffective in inducing complete stable remission similar to T-3B TS approach (Level _ evidence). VATET had theT-3B TS approach (Level _ evidence). VATET had the advantage of being easier to perform and having loweradvantage of being easier to perform and having lower morbidity and negligible esthetic sequelae.morbidity and negligible esthetic sequelae.
  • 39. QUESTION 5:QUESTION 5: What is the recommended pre-operativeWhat is the recommended pre-operative management?management?
  • 40. A. Consensus StatementA. Consensus Statement The objective of a pre-operative management is toThe objective of a pre-operative management is to ensure that there will beensure that there will be careful selectioncareful selection of patients forof patients for thymectomy to optimize its long term benefits. Thethymectomy to optimize its long term benefits. The patients must be in optimum medical condition prior topatients must be in optimum medical condition prior to surgery to avoid or minimize intraoperative and post-surgery to avoid or minimize intraoperative and post- operative complications.operative complications. Management in the peri-operative period requires aManagement in the peri-operative period requires a concerted effort among the neurologist, thoracic surgeon,concerted effort among the neurologist, thoracic surgeon, pulmonologist and other internists, the anesthesiologistpulmonologist and other internists, the anesthesiologist and the physiatrist.and the physiatrist.
  • 41. Practice RecommendationPractice Recommendation 5.15.1 What are the steps to follow during pre-What are the steps to follow during pre- operative management?operative management? 1. Perform a thorough neurologic evaluation and1. Perform a thorough neurologic evaluation and clearance: Ensure that the patient has optimumclearance: Ensure that the patient has optimum muscle power. When appropriate, correctmuscle power. When appropriate, correct oropharyngeal, bulbar and respiratory muscleoropharyngeal, bulbar and respiratory muscle weakness using the following regimen:weakness using the following regimen: a)a) anti-cholinesterase inhibitorsanti-cholinesterase inhibitors (pyridostigmine, neostigmine) and/or any of(pyridostigmine, neostigmine) and/or any of the following:the following: b)b) corticosteroids (prednisone, prednisolone)corticosteroids (prednisone, prednisolone)
  • 42. c) other immunosuppressants when these becomec) other immunosuppressants when these become necessary. Use of these, however, may requirenecessary. Use of these, however, may require several weeks to a several months before optimumseveral weeks to a several months before optimum therapeutic benefit is obtained.therapeutic benefit is obtained. d)d) plasmapheresis or intravenous immune-globulin,plasmapheresis or intravenous immune-globulin, when applicable, in patients with moderate towhen applicable, in patients with moderate to severe bulbar and respiratory muscle weakness orsevere bulbar and respiratory muscle weakness or in patients with a high titer of anti-Acetylcholinein patients with a high titer of anti-Acetylcholine Receptor antibodies.Receptor antibodies.
  • 43. 5.15.1 2. Acquire adequate pulmonary evaluation and clearance to2. Acquire adequate pulmonary evaluation and clearance to assure presence of patent airways, optimum respiratoryassure presence of patent airways, optimum respiratory muscle power, adequate clearing of secretions andmuscle power, adequate clearing of secretions and absence of respiratory infection.The following pre-absence of respiratory infection.The following pre- operative tests are recommended:operative tests are recommended: a) chest x-raya) chest x-ray b) arterial blood gasesb) arterial blood gases
  • 44. c) pulmonary function test (including VC, FEV, MEF,c) pulmonary function test (including VC, FEV, MEF, flow-volume loop) and exercise testing (with 6-8flow-volume loop) and exercise testing (with 6-8 hours off anticholinesterase inhibitor e.g.hours off anticholinesterase inhibitor e.g. Mestinon)Mestinon) d) sputum G/S, C/S when necessaryd) sputum G/S, C/S when necessary e) chest CT scan when necessarye) chest CT scan when necessary f) perfusion studies when necessaryf) perfusion studies when necessary
  • 45. 5.15.1 3.3. Perform cardiac evaluation as follows:Perform cardiac evaluation as follows: a) basic tests: ECG, chest x-ray;a) basic tests: ECG, chest x-ray; b) complete cardiology evaluation andb) complete cardiology evaluation and clearance ifclearance if - the patient is 40 years old or- the patient is 40 years old or aboveabove - if patient has history of ischemic- if patient has history of ischemic heart disease or other cardiac problems orheart disease or other cardiac problems or risks for developing cardiac problems.risks for developing cardiac problems.
  • 46. c) 2D echocardiography whenc) 2D echocardiography when necessarynecessary d) stress test when necessaryd) stress test when necessary e) nuclear medical tests whene) nuclear medical tests when necessarynecessary
  • 47. 5.15.1 4.4. Search for and adequately treat concomitant medicalSearch for and adequately treat concomitant medical conditions:conditions: a) Infectiona) Infection b)b) Disorders associated with MG. Do the followingDisorders associated with MG. Do the following tests:tests: - ESR- ESR - thyroid function tests- thyroid function tests - blood sugar- blood sugar - ANA- ANA - rheumatoid factor- rheumatoid factor c) Disturbance in nutrition, fluids andc) Disturbance in nutrition, fluids and electrolyteselectrolytes
  • 48. 5.15.1 5. Check CBC and bleeding parameters (CT, BT, PT,5. Check CBC and bleeding parameters (CT, BT, PT, PTT).PTT). 6. Refer to Rehabilitation Medicine specialist to assure6. Refer to Rehabilitation Medicine specialist to assure good pulmonary capacity and adequate muscle tone.good pulmonary capacity and adequate muscle tone. 7. Consider drug effects and drug interactions.7. Consider drug effects and drug interactions. If the patient is on medications, ensure that there are noIf the patient is on medications, ensure that there are no side effects of these drugs or adverse drug reactionsside effects of these drugs or adverse drug reactions that may interfere with or complicate the intra- andthat may interfere with or complicate the intra- and post-operative course of the patientpost-operative course of the patient (Refer to Table on(Refer to Table on Drug Effects and Interactions ).Drug Effects and Interactions ).
  • 49. Practice RecommendationPractice Recommendation 5.25.2 What is the recommendedWhat is the recommended anestheticanesthetic management?management? 1. Anesthesiologists must consider the patient’s disease1. Anesthesiologists must consider the patient’s disease severity including:severity including: - voluntary and respiratory muscle strength- voluntary and respiratory muscle strength - ability to protect and maintain patent airway- ability to protect and maintain patent airway post-operativelypost-operatively - the type of surgical procedure and the- the type of surgical procedure and the surgeons’ preferencessurgeons’ preferences - patient’s ongoing medication (e.g. Mestinon and- patient’s ongoing medication (e.g. Mestinon and steroids).steroids).
  • 50. 5.25.2 2. For pre-operative medications:2. For pre-operative medications: Generally, anxiolytics, sedatives andGenerally, anxiolytics, sedatives and opioids are rarely given to patients with littleopioids are rarely given to patients with little respiratory reserve.respiratory reserve. Small dose benzodiazepines, whenSmall dose benzodiazepines, when necessary, may be given to patients with goodnecessary, may be given to patients with good respiratory reserve.respiratory reserve.
  • 51. 5.25.2 3. Choice of anesthetic agents:3. Choice of anesthetic agents: The anesthesiologist must confer with theThe anesthesiologist must confer with the neurologist and the surgeon and other specialistsneurologist and the surgeon and other specialists when needed.when needed. There are several anesthetic agents that can be usedThere are several anesthetic agents that can be used (see Table on Anesthetic Agents).(see Table on Anesthetic Agents). There isThere is nono anesthetic technique that is superior toanesthetic technique that is superior to others. Choice depends on preference of theothers. Choice depends on preference of the doctors. These techniques have included:doctors. These techniques have included:
  • 52. a.a. Avoidance of muscleAvoidance of muscle relaxants and use ofrelaxants and use of potent inhaledpotent inhaled anesthetics both foranesthetics both for facilitating trachealfacilitating tracheal intubation andintubation and providing relaxation forproviding relaxation for surgery.surgery. b.b. Titration of small dosesTitration of small doses of intermediate actingof intermediate acting relaxants to the evokedrelaxants to the evoked EMG.EMG. c.c. Use of total intravenousUse of total intravenous anesthesia (TIVA).anesthesia (TIVA). d.d. Use of local or regionalUse of local or regional anesthetic techniques.anesthetic techniques. e.e. The decision whetherThe decision whether to reverse residual NMto reverse residual NM blockade at the end ofblockade at the end of surgery or to wait forsurgery or to wait for spontaneous recoveryspontaneous recovery and extubate whenand extubate when patient demonstratespatient demonstrates adequate parameters foradequate parameters for extubation remainsextubation remains controversial.controversial.
  • 53. 5.25.2 There is need to monitor patients especiallyThere is need to monitor patients especially noting interactions of the anestheticnoting interactions of the anesthetic agents with other drugs and keeping in mind theagents with other drugs and keeping in mind the variable responses the myasthenic patients mayvariable responses the myasthenic patients may havehave to the anesthetic drugs.to the anesthetic drugs.
  • 54. Practice RecommendationPractice Recommendation 5.35.3 Should pyridostigmine be continued orShould pyridostigmine be continued or discontinued pre-operatively?discontinued pre-operatively?
  • 55. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation Pyridostigmine or other anticholinesterase may bePyridostigmine or other anticholinesterase may be continued pre-operatively if the patient derivescontinued pre-operatively if the patient derives improved muscle strength with its use. The followingimproved muscle strength with its use. The following guidelines are recommended:guidelines are recommended: 1. To allow a decrease in the blood level pre-operatively,1. To allow a decrease in the blood level pre-operatively, give pyridostigmine or anticholinesterase 4 to 6 hours pre-give pyridostigmine or anticholinesterase 4 to 6 hours pre- operatively. In this way, it will not interfere with the anesthetic.operatively. In this way, it will not interfere with the anesthetic. Pyridostigmine may be resumed post-operatively.Pyridostigmine may be resumed post-operatively. 2. Pyridostigmine may cause increase in oral and tracheal2. Pyridostigmine may cause increase in oral and tracheal secretions especially in intubated patients. This can be titrated tosecretions especially in intubated patients. This can be titrated to avoid or minimize problems in post-operative pulmonary toilet.avoid or minimize problems in post-operative pulmonary toilet.
  • 56. B. Summary of EvidenceB. Summary of Evidence Omitting pyridostigmine pre-operatively mayOmitting pyridostigmine pre-operatively may reduce the need for muscle relaxant as well as lessen thereduce the need for muscle relaxant as well as lessen the effect of ester anesthetic agents. However, the omissioneffect of ester anesthetic agents. However, the omission of the pyridostigmine on the day of surgery predisposedof the pyridostigmine on the day of surgery predisposed myasthenic patients to the possibility of respiratorymyasthenic patients to the possibility of respiratory discomfort and sensitivity to vecuronium.7 (Class Idiscomfort and sensitivity to vecuronium.7 (Class I evidence)evidence)
  • 57. Practice RecommendationPractice Recommendation 5.4 Should corticosteroids be continued or5.4 Should corticosteroids be continued or discontinued pre- and peri- operatively?discontinued pre- and peri- operatively?
  • 58. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation Steroids should be continued pre-operatively inSteroids should be continued pre-operatively in steroid-dependent patients.steroid-dependent patients.
  • 59. B. Summary of EvidenceB. Summary of Evidence Steroid-dependent patients have the possibility ofSteroid-dependent patients have the possibility of developing post-operative deterioration or crisis so thatdeveloping post-operative deterioration or crisis so that they will require pre- and peri-operative coverage.8they will require pre- and peri-operative coverage.8 (Level 2 evidence)(Level 2 evidence) Steroids also decrease dose of non-depolarizingSteroids also decrease dose of non-depolarizing relaxants to which myasthenic patients are highlyrelaxants to which myasthenic patients are highly sensitive.sensitive.
  • 60. QUESTION 6:QUESTION 6: What is the recommended post-operativeWhat is the recommended post-operative management?management?
  • 61. A. Consensus StatementA. Consensus Statement Practice RecommendationPractice Recommendation 6.16.1 Closely monitor at Post-Anesthesia Care Unit orClosely monitor at Post-Anesthesia Care Unit or Surgical Intensive Care UnitSurgical Intensive Care Unit Respiratory support can be immediately institutedRespiratory support can be immediately instituted 6.26.2 Predict as accurately as possible the best time toPredict as accurately as possible the best time to extubate based on:extubate based on: - Pre-operative condition of the patient- Pre-operative condition of the patient - Surgical technique used- Surgical technique used
  • 62. 6.26.2 - Residual anesthetic effect- Residual anesthetic effect - Parameters for weaning include: absence of crisis- Parameters for weaning include: absence of crisis triggers, objective findings showing adequatetriggers, objective findings showing adequate muscle power, vital capacity > 10 ml/kg, negativemuscle power, vital capacity > 10 ml/kg, negative inspiratory force > 20 cm water, positiveinspiratory force > 20 cm water, positive expiratory force > 40 cm water.expiratory force > 40 cm water.
  • 63. Practice RecommendationPractice Recommendation 6.36.3 Predict as accurately as possible the need forPredict as accurately as possible the need for post-operative mechanical ventilation based on:post-operative mechanical ventilation based on: - Pre-operative condition of the patient- Pre-operative condition of the patient - Surgical technique used- Surgical technique used - Residual anesthetic effect- Residual anesthetic effect - Parameters: Kaneda 1995/Eisenkraft- Parameters: Kaneda 1995/Eisenkraft 1986/or Leventhal 19801986/or Leventhal 1980
  • 64. Practice RecommendationPractice Recommendation 6.46.4 Maintain adequate post-operative pain control.Maintain adequate post-operative pain control. Avoid muscle relaxants and tranquilizing drugs.Avoid muscle relaxants and tranquilizing drugs. 6.56.5 Maintain adequate pulmonary toilet andMaintain adequate pulmonary toilet and physical therapyphysical therapy 6.66.6 Avoid or use very cautiously drugs interferingAvoid or use very cautiously drugs interfering with neuro-muscular transmissionwith neuro-muscular transmission (Refer to Table on(Refer to Table on Drugs Acting on NM Junction))Drugs Acting on NM Junction))
  • 65. Practice RecommendationPractice Recommendation 6.76.7 Determine the best time to resumeDetermine the best time to resume pyridostigmine/anticholinesterase andpyridostigmine/anticholinesterase and steroids/immunesuppressants and the appropriatesteroids/immunesuppressants and the appropriate dose, considering that:dose, considering that: - Anticholinesterases can keep muscle power- Anticholinesterases can keep muscle power at adequate levels.at adequate levels. - Anticholinesterases can increase oral and- Anticholinesterases can increase oral and tracheal secretions.tracheal secretions. - Steroid-dependent patients will need- Steroid-dependent patients will need immediate post-operative coverage.immediate post-operative coverage.
  • 66. Thank you very much!Thank you very much!