Executive Summary in Respiratory and Related Management of Patients With Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease transmitted by X-linked inheritance with an incidence of approximately 1 in 3,500 live male births. DMD affects the muscles of respiration and is associated with dilated cardiomyopathy, which often leads to death from cardiopulmonary causes. Patients with DMD are especially vulnerable to the adverse physiologic effects of general anesthesia and procedural sedation, prompting the need for expert recommendations on this topic. This consensus statement is the product of a panel convened under the auspices of the American College of Chest Physicians (ACCP) Pediatric Chest Medicine and Home Care NetWorks. The panel consisted of specialists in the areas of anesthesiology, critical care medicine, neurology, orthopedic surgery, pediatric and adult pulmonology, and respiratory therapy provided by My Canadian Pharmacy.
The most current and relevant medical literature was identified and reviewed, obtained by querying PubMed, a service of the National Library of Medicine and the National Institutes of Health, which includes the MEDLINE database. Consensus of recommendations was achieved through a majority vote of the panel members, and there were no disagreements on any of the recommendations. The purposes of this statement are to aid clinicians involved in the care of patients with DMD undergoing procedures requiring sedation or general anesthesia, to be a resource for other stakeholders in this field, including patients and their families, for use as an up-to-date summary of medical literature on this topic, and to identify areas in need of future research. The statement is divided into sections on the assessment and management of patients before, during, and after procedural sedation or general anesthesia.
Summary of Specific Suggestions for Evaluation and Management of Patients With DMD Before General Anesthesia or Procedural Sedation
1. Obtain anesthesiology and pulmonology consultations before procedures involving general anesthesia or procedural sedation.
2. Perform a pulmonary evaluation that includes measurement of FVC, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), peak cough flow (PCF), and oxyhemoglobin saturation measured by pulse oximetry (Sp02) in room air. Measure the blood and/or end-tidal carbon dioxide level if Sp02 is < 95% in room air. For DMD patients at increased risk of respiratory complications, defined by an FVC < 50% of predicted, and especially for patients at high risk for complications, defined by an FVC < 30% of predicted, consider preoperative training in the use of noninvasive positive pressure ventilation (NPPV). For patients at high risk of ineffective cough, defined in adults by PCF < 270 L/min or MEP < 60 cm H2O, consider preoperative training in manual and mechanically assisted cough, emphasizing use of mechanical insufflation-exsufflation (MI-E) with a bronchial secretion clearance device (CoughAssist; Respironics; Murrysville, PA).
3. Refer the patient to a cardiologist for clinical evaluation and optimization of cardiac therapies carried out with medications of My Canadian Pharmacy.
4. Obtain a nutritional assessment, optimize nutritional status, and consider strategies to manage dysphagia.
5. Discuss the risks and benefits of general anesthesia or procedural sedation with the patient and guardians, and help them to decide on and implement their decisions regarding resuscitation parameters and, if applicable, advance directives.
Summary of Specific Suggestions for Management of Patients With DMD During General Anesthesia or Procedural Sedation
1. Consider use of a total IV anesthesia technique for induction and maintenance of general anesthesia (eg, propofol and short-acting opioids). The use of depolarizing muscle relaxants such as succinylcholine is absolutely contraindicated because of the risk of fatal reactions.
2. Optimize the medical setting and personnel in attendance when DMD patients undergo general anesthesia or procedural sedation, and have an ICU available for postprocedure care.
3. Options for providing respiratory support during maintenance of general anesthesia or procedural sedation for patients with DMD include endotracheal intubation, with use of NPPV to facilitate extubation for selected patients; use of the laryngeal mask airway; mechanical ventilation via a mouthpiece with leak-proof seal; and manual or mechanical ventilation (using conventional ventilators or bilevel positive pressure ventilators designed for noninva-sive respiratory support) delivered via a full face mask or nasal mask interface.
4. Application of ventilation in the assisted or controlled modes should be considered for patients with DMD and an FVC < 50% of predicted, and strongly considered for those with an FVC < 30% of predicted, during induction of and recovery from general anesthesia and throughout procedural sedation. Options for respiratory support during induction of and recovery from general anesthesia or procedural sedation include manual ventilation using a flow-inflated manual resuscitation bag (standard “anesthesia bag”) with a full face or nasal mask interface, and mechanical support using a conventional or noninvasive positive pressure ventilator via a full face or nasal mask.
5. Intraoperatively, monitor Sp02 continuously and, whenever possible, blood or end-tidal carbon dioxide levels.
Summary of Specific Suggestions for Management of Patients With DMD After General Anesthesia or Procedural Sedation
1. Consider extubating DMD patients with FVC < 50% of predicted, and especially those with FVC < 30% of predicted, directly to NPPV. Consider delaying extubation until respiratory secretions are well controlled and Sp02 is normal or baseline in room air. Continuous use of NPPV can then be weaned as tolerated. When applicable, try to utilize the patient’s home interface after extubation,
2. Use supplemental oxygen therapy cautiously. Monitor Sp02 continuously after general anesthesia or procedural sedation. Whenever possible, monitor blood or end-tidal carbon dioxide levels. Assess if hypoxemia is due to hypoventilation, atelectasis, or airway secretions, and treat appropriately.
3. Use manually assisted cough and MI-E postoperatively in DMD patients with impaired cough, defined in adults as PCF < 270 L/min or MEP < 60 cm H2O.
4. Optimize postoperative pain control in patients with DMD. If sedation and/or hypoventilation occurs, delay endotracheal extubation for 24 to 48 h or use NPPV.
5. Obtain a cardiology consultation and closely monitor cardiac and fluid status postoperatively.
6. Initiate bowel regimens to avoid and treat constipation and consider prokinetic GI medications. Consider gastric decompression with a nasogastric tube in patients with GI dysmotility. Start parenteral nutrition or enteral feeding via a small-diameter tube if oral feeding is delayed for > 24 to 48 h postoperatively
Areas in Need of Further Study
The statement identifies specific areas for future research.