Approach Considerations
The treatment of patients with diaphragmatic dysfunction is dependent on the underlying etiology as well as the presence or absence of symptoms. Patients with unilateral diaphragmatic paralysis are typically asymptomatic and do not need treatment. These patients may have some dyspnea with exertion or if they have an underlying pulmonary disease. Treatment should be considered when dyspnea is out of proportion to the physical exertion. Bilateral diaphragmatic weakness is much more severe and may require treatment.
In cases involving anatomic causes and defects, the only treatment option is surgical repair. Neuromuscular processes, depending on the etiology, can generally be treated medically. If diaphragmatic disease is secondary to an underlying medical etiology, treatment of that disease often improves diaphragmatic weakness. For example, bilateral diaphragm dysfunction due to shrinking lung syndrome, connective-tissue disease, hypothyroidism, or malnutrition may improve with treatment of the primary disease.
The use of medication is limited to the etiology of neurologic involvement.
Medical Care
Many patients with severe bilateral diaphragmatic dysfunction require ventilatory support. This may range from nocturnal to continuous, and from noninvasive to invasive. General indications for initiating nocturnal noninvasive ventilator support include a daytime partial pressure of carbon dioxide above 45 mm Hg, nocturnal oxygen saturations of 88% or lower for five consecutive minutes, a maximal inspiratory pressure (MIP) below 60 cm H2O or a forced vital capacity of less than 50% predicted. [4] In the case of patients with concomitant chronic respiratory or cardiac disease, transient ventilatory support may be required in situations of cardiac or respiratory instability, such as with respiratory infections, pulmonary edema, or bronchospasm. [5]
Patients with cor pulmonale also may manifest improvement in function and correction of blood gas abnormalities with nighttime or intermittent daytime noninvasive ventilation. [54]
If the patient does not respond to nasal or oral positive-pressure ventilation, alternative forms of therapy such as negative-pressure cuirass ventilation or jacket ventilator/airtight body suit (eg, Pulmo-Wrap), rocking bed, or positive-pressure pulmo-belt can be used.
Patients undergoing pulmonary rehabilitation have been shown to have improved diaphragmatic contractility, [55] and it may be of benefit to patients who suffer from diaphragmatic dysfunction. [56]
Tracheotomy with positive-pressure intermittent or permanent ventilation is reserved for patients with life-threatening or irreversible disease such as amyotrophic lateral sclerosis.
Diaphragmatic pacing may be of benefit to patients with bilateral diaphragmatic weakness who have intact phrenic nerves, such as patients with high-level cervical spinal injuries or patients with central hypoventilation. [57] This therapy is limited, and often diaphragmatic pacing does not result in sustained, independent ventilation. Progressive reconditioning is recommended when using a diaphragmatic pacer. High stimulating frequencies and a prolonged period of pacing may lead to irreversible muscle dysfunction. Patients with diaphragmatic pacing require tracheotomies, because pacer-induced breathing is not synchronized with the upper airway. [58]
Intraperitoneal diaphragm pacing has been evaluated in the use of patients with amyotrophic lateral sclerosis with poor results. A multicenter, randomized controlled trail to evaluate the safety and efficacy of the use of intraperitoneal diaphragm pacing across seven centers in the United Kingdom was terminated early following a statistically significant excessive mortality in the group receiving diaphragm pacing. [59]
Surgical Care
Surgery is indicated in the management of anatomic defects in the diaphragm. The type of surgical intervention depends on the anatomic defect or problem.
Congenital defects
Manage congenital diaphragmatic defects through transabdominal primary surgical repair.
Acquired defects
Acquired diaphragmatic defects (ie, traumatic rupture, late-onset congenital diaphragmatic defect) are typically managed by thoracoscopic plication of the hemidiaphragm. Plication usually results in improved lung function and exercise endurance, and less dyspnea. Plication of the diseased diaphragm improves ventilation to the well-perfused lung and improves gas exchange, which improves static lung mechanics.
In a selected group of patients, plication of the diaphragm improved vital capacity by 10%-20% as well as improved the partial pressure of arterial oxygen (PaO2) by 10%. [60]
A surgical series reported improvement in forced tidal volume from 216 mm/GHz to 415 mm/GHz postplication, and mechanical ventilatory support could be discontinued 2-12 days after plication. Plication can also be achieved by video-assisted thoracoscopy. [13]
Phrenic nerve injury
Primary repair of phrenic nerve damage from trauma can be attempted but does not generally restore function. With expectant treatment, few patients regain phrenic nerve function.
Manage injury from a tumor by resection of the tumor encasing the phrenic nerve. Most patients regain function of the nerve.
Cold phrenic nerve injury during cardiac surgery generally resolves with conservative management.
Spinal cord injury or phrenic nerve injury
Diaphragmatic pacing is an investigational technology that allows the placement of electrodes within the diaphragm that stimulate the diaphragm to contract. This can be performed either transthoracically or transabdominally. The more recent studies support the use of laparoscopy and thoracoscopy.
Consultations
A multidisciplinary approach to the diagnosis and management of diaphragmatic dysfunction is best. Note the following:
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Pulmonologists trained in diaphragmatic assessments are vital to perform and interpret diagnostic studies to ascertain the presence and severity of diaphragmatic dysfunction.
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Thoracic surgeons should be consulted for evaluation of surgical plication or placement of diaphragmatic pacing.
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Neurologists should be consulted when electromyography or diaphragmatic pacing is considered.
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Surgical procedures require postprocedural monitoring in an intensive care unit.
Diet and Activity
Diet
No specific dietary modifications have been shown to benefit patients with diaphragmatic dysfunction.
For obese patients, weight reduction has been shown to improve respiratory function. [56]
Malnutrition and electrolyte disturbances related to poor nutritional status in patients in the intensive care unit have been shown to worsen ventilator-induced diaphragmatic dysfunction. [61]
Activity
In general, patients should have no activity restrictions and should have activity as tolerated. Early mobilization, particularly after invasive procedures or during a stay in the intensive care unit, is beneficial for diaphragmatic strength and recovery. Mechanical ventilation alone should not be a contraindication for mobilization. Patients undergoing pulmonary rehabilitation have been shown to have improved diaphragmatic contractility, [62] and it may be of benefit to patients who suffer from diaphragmatic dysfunction. [55]
Long-Term Monitoring
Once an anatomic defect is corrected, the patient should undergo periodic chest radiography and assessment of pulmonary function, including upright and supine pulmonary function testing (PFTs) and maximal inspiratory pressures (MIPs). Although the rate of spontaneous recurrence of a repaired diaphragmatic hernia is low, small defects in the repair site have been reported.
Patients with progressing disease should be routinely monitored for the development of nocturnal desaturations or daytime hypercarbia.
If diaphragmatic dysfunction was secondary to a tumor encroaching on the phrenic nerve, maintaining close follow-up contact with the patient is important to ensure that the neoplasm has not recurred.
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Diaphragm Disorders (Diaphragmatic dysfunction). Radiograph of a man who fell 45 ft from scaffolding, through plate glass windows, and onto the ground. Intraoperatively, he had a completely avulsed diaphragm on the left side. The patient subsequently recovered after a 45-day hospital course of treatment.
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Diaphragm Disorders (Diaphragmatic dysfunction). Congenital diaphragmatic hernia is shown in this coronal obstetric ultrasound (the patient's head is to the right of the image; the thorax is center, and the abdomen is left). The stomach (st) and heart (hrt) are both within the thorax. Courtesy of Wikipedia (https://en.wikipedia.org/wiki/File:Cdh0002.jpg), author Dr Laughlin Dawes.
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Diaphragm Disorders (Diaphragmatic dysfunction). Sagittal computed tomography scan of the chest with intravenous contrast demonstrates a Morgagni hernia (red arrow) containing abdominal fat. Courtesy of Wikipedia (https://en.wikipedia.org/wiki/File:Morgagni_Hernia.PNG), author Jason Robert Young, MD.
