PART 5 in Microsoft Office

Creating Denso QR Bar Code in Microsoft Office PART 5

hospital for observation of respiratory, autonomic, and motor function The comments that follow are applicable to most other forms of acute and subacute neuromuscular respiratory failure such as myasthenia gravis Measurement of maximal inspiratory force and expiratory vital capacity suf ces for the bedside estimation of the adequacy of diaphragmatic strength and respiratory function The trend of these measurements are a guide to the likelihood of respiratory failure As in poliomyelitis, the strength of the neck muscles and trapezii, which share the same segmental innervation as the diaphragm, tends to parallel diaphragmatic strength A rough estimate of breathing capacity may be obtained by having the patient count quickly on one deep breath The ability to reach 20 generally corresponds to a vital capacity of greater than 15 L If a downward trend in these measurements is recognized and the vital capacity diminishes to below about 10 mL/kg, endotracheal intubation and mechanical ventilation are considered It should be noted that a fairly severe degree of impaired ventilation may occur before the rst sign of dyspnea appears and even before there is any elevation of arterial carbon dioxide content Incipient respiratory failure generally coincides with tachypnea and a slight decrease in arterial oxygen tension (PO2 less than 85 mmHg) re ecting pulmonary atelectasis If respiratory failure arises gradually, over days or longer, there is slight tachycardia, diaphoresis, restlessness, and tachypnea Attempts to forestall the use of a positive-pressure ventilator by negative-pressure cuirass-type devices have been unsatisfactory in our experience Patients with oropharyngeal weakness require intubation even earlier in order to prevent aspiration, but mechanical ventilation is not always necessary at the same time These treatments are so demanding that the patient should be admitted to an intensive care unit staffed by personnel skilled in maintaining ventilation and airway patency The other major aspects of the treatment in severely affected patients involve the management of cardiovascular autonomic instability and the prevention of the many general medical problems that attend any immobilizing critical illness Hypotension from dysautonomia, which occurs in about 10 percent of severely affected patients, is treated by intravenous volume infusion and by the use of vasopressor agents for brief periods Extremes of hypertension are managed by short-acting and titratable antihypertensive medications, such as intravenous labetalol The choice and dosing of an antihypertensive drug is important, since these episodes may be rapidly succeeded by precipitous declines in pressure It is not clear if severe autonomic changes can be anticipated but various provocative maneuvers such as ocular pressure to elicit heart block are used in some units; we generally omit them Prevention of electrolyte imbalance, gastrointestinal hemorrhage, and particularly pulmonary embolism in patients who are bedbound (by the use of subcutaneous heparin or pneumatic compression boots), all require careful attention Adynamic ileus is a problem in some cases, manifest rst by abdominal pain coincident with nasogastric tube feeding and by bloating; it may lead to bowel perforation even if feeding is discontinued As mentioned, a number of patients become hyponatremic, usually from SIADH but occasionally from a natriuresis, and the drop in sodium may be produced or exaggerated by positive-pressure mechanical ventilation The distinction between the two conditions that cause hyponatremia determines the course of treatment: uid restriction in the case of SIADH or salt replacement in the case of sodium loss Many patients have bizarre waking dreams or hallucinations

after weeks of immobilization A mode of communication should be worked out by the nursing staff, preferably before the patient is intubated Failure to effectively clear the tracheobronchial airways and the need for prolonged mechanical ventilation are the usual indications for tracheostomy In most cases this procedure can be postponed until the end of the third week of intubation However, patients who become rapidly quadriplegic and ventilator-dependent may require tracheostomy earlier Once tracheostomy is performed, careful tracheal toilet and treatment of pulmonary and urinary tract infections by the use of appropriate antibiotics are required Prophylactic antibiotic treatment is not recommended With tracheostomy and intensive care, the mortality from the disease can be reduced to about 3 percent (Ropper and Kehne) (see further on under Prognosis ) The decisions to wean and then discontinue respiratory aid and to remove the endotracheal or tracheostomy tube are based on the degree and timing of recovery of respiratory function The weaning process generally begins when the vital capacity reaches approximately10 mL/kg and comfortable breathing can be sustained for a few minutes The relative merits of the numerous methods of delivering positive pressure volume-cycled ventilation and its gradual withdrawal are too complex to be covered here but the reader is referred to the monograph, Neurological and Neurosurgical Intensive Care, by Ropper and colleagues Physical therapy (passive movement and positioning of limbs to prevent pressure palsies and, later, mild resistance exercises) should begin once they can be comfortably undertaken Plasma Exchange and Immune Globulin Speci c treatment of the presumed immune disorder that underlies GBS includes plasma exchange (PE) and intravenous immunoglobulin (IVIG) Our practice has been to closely observe patients who are still able to walk for several days If the patient has become unable to walk unaided or if he shows a signi cant reduction in vital capacity or signs of severe oropharyngeal weakness, plasma exchange or IVIG (not both) is instituted promptly This typically occurs at the fth to tenth day after the appearance of the rst symptoms but may be as early as one day or as late as 3 weeks Three large randomized trials comprising more than 500 patients have established the usefulness of plasma exchange administered during the evolving phase of GBS In patients who are treated within 2 weeks of onset, there is an approximate halving in the period of hospitalization, in the duration of mechanical ventilation, and in the time required to achieve independent ambulation However, in the largest trial, if the rst plasma exchange was delayed for 2 weeks or longer after the onset of the disease, the procedure was of little value Nonetheless, if a patient continues to progress in the third or fourth week of illness, it is probably still appropriate to institute the exchanges The most important predictors of responsiveness to plasma exchange treatment are the patient s age (responders are younger) and the preservation of motor compound muscle action potential amplitudes prior to instituting treatment (McKhann et al) One study has found that the overall condition of patients was better at 6 and 12 months after treatment as compared to untreated patients; other studies have been equivocal on this point The advised regimen of plasma exchange removes a total of 200 to 250 mL/kg of plasma in four to six treatments on alternate days, or over a shorter period if there is no coagulopathy The replacement uid is saline combined with 5% albumin The need