Prolonged Respirator Support for the Treatment of Intractable Myasthenia Gravis

changes due to closed chest trauma could not have been responsible for any of the ruptures.

FICURE 2. View through opened left ventricle demonstrates ruptured papillary muscle (arrow) . Cotton has been placed into right ventricle and can be seen as light area through septal defect at end of probe. the left ventricular lumen." Septal ruptures have been associated with inferior damage in less than 25 percent of acute myocardial Infarctions," whereas it is usual for papillary involvement to occur with posterior or inferior locations," Furthermore, posterior papillary involvement is four times as frequent as anterior papillary muscle damage." W idening of the mediastinum led to speculation that an aortic dissection or rupture of the free ventricular wall had occurred. In retrospect, this widening may have been due to venous engorgement from acute tricuspid insufficiency caused by right ventricular overload from the ventricular septal defect. The sudden appearance of a loud systolic murmur and thrill favors the diagnosis of perforation. There has been at least one case report however, in which a thrill has been associated with papillary muscle involvement and incomplete rupture without septal perforation." The only published cases similar to ours were those observed by Skoulas and Beier- in 1967, and by Rawlins et al in 1972. 8 In the earlier of these, a small defect was found only after a careful anatomic search. Approximately half of the base of the posterior muscle was necrotic, without definite rupture. In the more recent case, both a septal defect and mitral regurgitation were documented by cineangiography. Their patient had been free of any cardiac murmurs prior to his acute ischemic episode. The autopsy showed that the posterior papillary muscle was fibrotic and distorted, but not ruptured. In our case it is impossible to assess exactly which of the lesions of septal defect and papillary muscle rupture came first. The early systolic ejection murmur heard initially was attributed to turbulence originating in the left ventricular outflow tract. The postmortem discovery of a calcified septal aortic leaflet is consistent with this finding. There was no thrill during the final event, which can be explained by the presence of severe hypotension. Furthermore, the cause of death was pulmonary edema, a characteristic finding in acute severe mitral insufficiency. Resuscitation was not attempted; thus, postmortem

CHEST, 65: 2, FEBRUARY, 1974

1 Lynch RP, Edwards JE: (1966) Pathology of coronary atherosclerosis and its complications. In The Heart (Hurst JW, Logue RB, eds), (ed 2) . New York, McGraw-Hill, 1966, pp 918-919 2 Lundberg S, Soderstrom J: Perforation of the interventricular septum in myocardial infarction. A study based upon autopsy material. Acta Med Scand 172:413,1962 3 Skoulas A, Beier RL: Dissecting perforation of infarcted interventricular septum with associated posterior papillary muscle involvement. Am J Med 43:461, 1967 4 Sanders RJ, Kern WH, Blount SG Jr : Perforation of the interventricular septum complicating myocardial infarction. Am Heart J 51:736, 1956 5 Sanders RJ, Neubuerger KJ, Ravin A: Rupture of papillary muscles, occurrence of rupture of the posterior muscle in posterior myocardial infarction. Chest 31:316,1957 6 Orlando MD, Wooley CF, Scorpelli D, et aI: Papillary muscle infarction without rupture producing mitral regurgitation. Circulation (SuppI3) 30:136, 1964 7 Hope RB, Askey JM: Necrosis of a cardiac papillary muscle following infarction with incomplete rupture. Am Heart J 44:306, 1952 8 Rawlins MD, Mendel D, Braimbridge MV: Ventricular septal defect and mitral regurgitation secondary to myocardial infarction. Br Heart J 44:306, 1972

Prolonged Respirator Support for the Treatment of Intractable Myasthenia .* Gravis Paul A. Selecky, M.D., and Irwin Ziment, M.D.

The advent of modem respiratory care bas provided the ability to maintain patients on full respirator support via a tracheostomy for prolonged periods, without serious sequelae. We recently bad the opportunity to care for a patient who suffered from severe neuromuscular weakness secondary to myasthenia gravis. This necessitated continuous respirator support for a total of 661 days, a duration previously onreported.

T

he availability of specialized team care in the mod ern hospital intensive care unit (leU) has greatly improved the prognosis in certain disease states. We describe here a patient with a case of myasthenia gravis that was particularly intractable to many modes of therapy. The neuromuscular weakness was so severe that she required almost continuous respirator support via a cuffed tracheostomy tube for a total of 661 days, the longest period on record.t-s °From the Respiratory Division, UCLA School of Medicine, Harbor General Hospital Campus, Torrance. Reprint requests: Dr. Selecku, 1000 West Carson, Torrance,

Cal. 90509

PROLONGED RESPIRATOR SUPPORT IN MYASTHENIA GRAVIS 207

received respirator support from a pressure-cycled respirator (Bird, Mark 10, with heated Ohio nebulizer). Under this management, she had periodic occurrences of atelectatic infiltrates on chest roentgenogram associated with mild fever but no evidence of a respiratory pathogen. Close observation subsequently revealed that frequent lung inflations to her total lung capacity (TLC) prevented atelectasis. This was achieved by changing to a volume-cycled respirator (Bennett MA-l) with an automatic "sigh" mechanism that provided paired inflations to TLC 15 times/hour. Inspired oxygen concentration was maintained at 21 percent during most of her hospital course. It was occasionally increased to 30 percent during transient episodes of platelike atelectasis, but never higher. The alveolar-arterial P02 diHerence fluctuated between 30-35 mm Hg. A Rusch red rubber double-cuffed tracheostomy tube was in place at all times. The cuffs were inflated alternately every hour during the early part of her hospitalization, but the tracheostomy stoma gradually enlarged, such that inflating the upper cuff caused it to bulge out into the stoma. Subsequently only the lower cuff was used. The details of her tracheostomy care are listed in Table 1. In March, 1972, after 15 months of hospitalization, the patient was given a five-week course of antilymphocyte globulin (ALG). She began to show improvement, but in May, 1972 developed fever, with chest and epigastric pain. A diagnosis of polyserositis was made, with documented pancreatitis, pericarditis and effusion, and pleurisy with effusion on the left. Multiple studies of pleural fluid, including a pleural biopsy, were nondiagnostic. All skin tests except dinitrochlorobenzene (DNCB) were also negative. The findings gradually subsided on supportive management. In July, 1972 a course of alternate-day, high-dosage (100 mg ) prednisone was repeated. Within several weeks, the patient began to demonstrate gradual but progressive improvement in muscle strength. By Sept. 28, 1972, her vital capacity increased to over 1,200 ml (Fig 1) and persisted as such throughout the day; she was then transferred to the ward, some 652 days after admission to the ICU (Table 2). Her tracheostomy was left in place, but the cuff could now remain deflated for the first time since it was installed Nov. 25,1970. At the time of discharge on Nov. 22, 1972, the patient was unable to completely appose her vocal cords. The tracheos-

CASE REPORT

The patient is a 47-year-old woman who developed right facial weakness and progressive fatigue in May, 1970. An edrophonium chloride (Tensilon) test and an electromyogram were consistent with the diagnosis of myasthenia gravis. The patient initially responded to therapy until hospitalization was required on Aug. 10, 1970 because of respiratory distress. Tracheostomy was performed Aug. 16, 1970 after an episode of cardiorespiratory arrest. With improvement in the patient's strength, the tracheostomy was discontinued on Sept. 23, 1970, and the patient was subsequently discharged. Because of progressive weakening, she was rehospitaIized Oct. 30, 1970. Tracheostomy was again performed on Nov. 25, 1970, and following respiratory arrest while not using the respirator, she was transferred to Harbor General Hospital Dec. 16, 1970 for further management in the medical-respiratory intensive care unit. At the time of admission she was on assisted ventilation by a pressure respirator. There was generalized muscle weakness, with ptosis and masklike facies. Results of initial laboratory tests were within normal limits, except for arterial blood gas values on the respirator, which revealed a slight respiratory alkalosis. Vital capacity was 400 ml. A treatment program of pyridostigmine bromide (Mestinon ), neostigmine methyIsuIfate (Prostigmine), amebonium chloride (Mytelase}, neostigmine, ephedrine, oxtriphyIline ( Choledyl ) and guanidine hydrochloride in varying dosages, combinations and durations was begun with no persistent benefits. ACTH and high-dosage prednisone were also given without success. Chest roentgenogram revealed a mediastinal mass, which was excised Jan. 18, 1971; it proved to be a benign thymoma. Subsequently, the mediastinum was irradiated with 4,000 rads during July, 1971. There was again no consistent response to these therapeutic maneuvers. During her hospitalization, the patient's dependence on the respirator was almost always total. There was a third and a fourth cardiorespiratory arrest; both occurrences were attributed to respirator failure. Daily measurement of her vital capacity (2,600 ml predicted) ranged widely from 50-1,200 ml (Fig 1). Arterial blood gas measurements repeatedly revealed a mild, fully compensated respiratory alkalosis. During the early part of her acute illness, the patient

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208 . SELECKY, ZIMENT

CHEST, 65: 2, FEBRUARY, 1974

Table I-RouliRe Reap;raIDry Care 1. Tracheostomy care: (a) change tracheostomy tube weekly (b) sterile tracheal suctioning technique hourly; deflate cuH concurrently (c) constant humidification of airway (d) inflate cuff to minimal occluding volume (e) culture of deep tracheal aspirate semiweekly (or more often if indicated) (f) Polymyxin ointment around tracheostomy stoma twice daily (g) Nebulizer therapy: Bronkosol, qid; occasional polymyxin B for Pseudomonas colonization 2. Respirator care: (a) Use of volume respirator, with adequate monitoring systems and alarms (b) Use of pressure respirator when patient's spontaneous tidal volume is greater than 300 ml (c) Measurements of vital capacity 3 times a day (d) Replace respirator tubing daily (e) Replace heated cascade humidifier daily; replace sterile water q 8 hrs (f) Fifteen paired lung inflationsto TLC hourly ( g) Machine settings (eg, FI02, VB, airway pressure) adjusted to maintain normal arterial blood gas levels 3. General care: (a) Physical therapy daily, ie, postural drainage with chest percussion, and passive and active limb movements (b) Occupational therapy daily (c) Measurement of blood gas levels at least once a week (d) Patient out of bed when possible (e) Position changed q 2-4 hrs when flaccid

tomy was therefore left in place (cuH deflated). Her care at home includes periodic self-suctioning of the tracheostomy cannula, as well as continued administration of prednisone. Because of difficulty swallowing, alimentation via a nasogastric tube is being continued at home. Her course as an outpatient continues to show progress in the return of muscular strength. DISCUSSION

The patient presented here demonstrates a prolonged course of myasthenia gravis that was largely unresponsive to the standard treatment of this disorder." As a result, the patient required ventilatory assistance via a respirator for a total of 661 days to prevent respiratory failure. This necessitated the continued use of an indwelling cuffed tracheostomy tube throughout the whole period, a duration that has not been previously described. In the past, it was common practice to consign the paralyzed or myasthenic patient to a tank-respirator, because it was felt that the use of a respirator with a tracheostomy was associated with greater morbidity. This case report illustrates that it is possible to success-

Single ICU stay = 652 days Cuffed tracheostomy and respirator 661 days

=

(12/16/70- 9/28/72) (11/25/70- 9/16/72)

Combined hospitalization = 735 days (10/30/70-11/22/72)

CHEST, 65: 2, FEBRUARY, 1974

fully manage a totally dependent, tracheostomized patient on a respirator for an indefinite period. Careful attention to the routine care of the patient and respirator by an interested nursing team and inhalation therapy service can minimize complications. This requires constant monitoring of all parameters as listed in Table 1, in order to prevent many of the problems associated with chronic respirator use, such as oxygen toxicity, infection, "respirator lung," and simple mechanical failure.' The use of a cuffed tracheostomy tube is subject to a myriad of complications," which are thought by many investigators to be prevented by the use of meticulous tracheostomy care." The fact that this patient survived such a long course without these complications is plainly a tribute to her over-all nursing care. The modem concept of acute respiratory care includes the integration of multiple specialities, including nursing, inhalation therapy, physical and occupational therapy, as well as general psychologic support for the patient." The cost of such care is significant, but the total benefits achieved by this patient, as well as the many members of the health care team who participated in her care, readily underwrite such expenditures," Not all patients with respiratory failure will respond to prolonged ICU care. Careful selection of patients, however, such as those with reversible neuromuscular disease, can lead to gratifying results. In summary, this case report illustrates that the team concept of acute respiratory care can be extended to the prolonged chronic care of the occasional patient who is in need of such attention. In addition, the prolonged course of myasthenia gravis is depicted, as is the importance of providing adequate respiratory support to the severely ill patient, while awaiting a remission or a response to therapy. ACKNOWLEDGMENT: We wish to acknowledge the staff of the Intensive Care Unit and multiple house staff members who participated in this patient's care, as well as Dr. Jon Dorman, Division of Neurology, who supervised the treatment of her myasthenia gravis.

1 Whitehouse AC, Petty TL: Recovery in Landry-GuillainBarre syndrome after prolonged respiratory support. Lancet 1:1029-1030, 1969 2 Safar P, Berman B, Diamond E, et al: CuHed tracheotomy tube vs tank respirator for prolonged artificial ventilation. Arch Phys Med Rehabil43:487-493, 1962 3 Flacke W: Treatment of myasthenia gravis. N Eng! J Med 288:27-31,1973 4 American Thoracic Society Committee on Therapy: Principles of respiratory care. Am Rev Resp Dis 95:327-337, 1967

5 Cooper JD, Grillo HC: Analysis of problems related to cuffs on intratracheal tubes. Chest [Suppl] 62:21S-27S, 1972 6 Bendixen HH, Egbert LD, Hedley-Whyte J, et al: Respiratory Care. St. Louis, CV Mosby Co, 1965, p 116 7 O'Donohue WJ, Baker JP, Bell GM, et al: The management of acute respiratory failure in a respiratory intensive care unit. Chest 58:603-610, 1970 8 Griner PF: Medical intensive care in the teaching hospital: Costs versus benefits. Ann Intern Med 78:581-585,1973

PROLONGED RESPIRATOR SUPPORT IN MYASTHENIA GRAYIS 209