The lungs require the strength of many muscles to help a person to breathe and cough. As people with Duchenne grow older, the respiratory muscles, like the skeletal muscles, become weaker. Like the heart, every person with Duchenne will have pulmonary issues of some type.
The goal of pulmonary care is to allow both the prevention and management of respiratory complications. This is such an important area of care and concern that we pulled together pulmonary experts from across the US to address these important issues.
This fall, PPMD is presenting a three part series on the pulmonary care of patients living with Duchenne. The second webinar in the series addressed Duchenne pulmonary care for tweens & teens on October 29th.
- Dr. Jonathan Finder (Children’s Hospital of Pittsburgh)
- Dr. Oren Kupfer (Children’s Hospital Colorado)
Recording & Summary
Stages of Respiratory Function
Stage I: Normal (0-10yo)
Stage 2: Inadequate cough (10-15yo)
- Often normal cough until respiratory infection
- Cough Peak Flow: <270 L/Min: indication for the need to assist cough
- Manually assisted cough: use Ambu bag or “frog breaths” to hyper-inflate (over-fill) lungs – use abdominal thrusts or thoracic squeeze to express air (do on an empty stomach; may not be as effective with scoliosis or chest wall contractures
- Mechanically assisted cough: can be done using a mask, mouthpiece, trach (preferred and more effected than direct tracheal suctioning for patients with trach); appropriate for all patients; prophylactic use (“breath stacking” (link to previous webinar) may prevent areas of collapse in lungs and help with chest wall compliance/flexibility); several different types of mechanical cough devices are available. (the smaller version is the Respironics T70: itmay be difficult to obtain insurance coverage if you already have the older model)
- How to use a Cough Assist
- Inspiratory phase: Set inspiratory pressure 20-35cm H2O
- Hold at target inspiratory pressure for 1-2 seconds
- Expiratory phase: Setexpiratory pressure for 30-50cm H2O for approximately seconds (range 1-3 seconds, as tolerated and to effect)
- 5 cycles then suction if needed
- Repeat x 5 sets total (25 breaths)
- Oxygen: warning!! Supplemental oxygen can be dangerous
Giving oxygen can suppress the sensation a need to breathe and lead to respiratory arrest in those who have been retaining CO2 (hypoventilating). Low oxygen saturations may indicate that the patient needs airway clearance (cough assistance) but could also indicate a need for assisted ventilation. Checking CO2 level is necessary to determine if ventilator assistance is needed. (needed if CO2 >45); l; Low oxygen levels can also be caused by atelectasis (collapsed airways), pneumomia, or a mucus plug.
Stage 3: Need for Nocturnal Ventilation (Inadequate nighttime ventilation (16-20yo)
- Pulmonary function test: FVC (forced vital capacity) <30% usually correlates to a need for nocturnal ventilator support and is an indication for getting a sleep study; look for signs of inadequate breathing in sleep such as morning headaches, frequent wakening during the night, poor daytime attention/performance, high retained CO2 on sleep study
- Tracheostomy and oxygen should not be first responses
- Breathing support such as BiPAP (or V-PAP) is necessary in Duchenne for respiratory assistance; CPAP is only appropriate for the management of obstructive sleep apnea (a problem for 30% of younger patients with Duchenne – maybe because of increased weight, steroids, decreased mouth/throat muscle tone, large tongue? Also muscle strength is decreased while lying down); sleep study is needed to titrate the breathing support so that it is comfortable for the user and meets the user’s needs
- A good mask fit is essential for success (no one will sleep in an uncomfortable mask).
Stage 4: Inadequate daytime ventilation (>18yo)
- Indicated with PCO2 >45, hemoglobin <92 when awake
- NIV (non-invasive ventilation): BiPAP or VPAP; managed with mouthpiece; Philips-Respironics Trilogy or Pulmonetics LTV 1150, or other lightweight home ventilator
Anesthesia and Duchenne
- Assess pulmonary function/risks prior to surgery/anesthesia
- FVC (forced vital capacity
- FVC <50% normal increased risk
- FVC<30% high risk
- PCF (peak cough flow)
- <270 L/min increased risk
- <160 L/min high risk
- MEP (mean expiratory pressure)
- Be sure anesthesia is aware of underlying diagnosis (risks of some anesthesia with Duchenne. NO SUCCINYLCHOLINE; use caution with all anesthesia); use IV anesthesia if possible
- Post-op Care
- Extubate directly to BiPAP (especially if it was used previously); stay on BiPAP until completely awake
- Airway clearance (cough assist preferable to incentive spirometery)
- Pain medication: balance pain control with ability to maintain ventilation. OK to stay on BiPAP if needed while there is suppression of breathing from narcotic pain medication.
- Is a vibrating chest compression device (“The Vest,” among others) indicated in Duchenne?
Not usually (unless there is trapped mucus in the lungs). In Duchenne, the inability to cough or to increase oxygen levels is due to weakness of the diaphragm and the other breathing muscles to take a deep breath in and to force air out. High frequency chest wall percussion is used for patients with impaired mucociliary clearance disorders like cystic fibrosis. Most patients with DMD have normal mucociliary clearance and will therefore not benefit from use of a Vest. “IPV” is intrapulmonary percussive ventilation, and is a therapy used in some hospitals to aid in airway clearance in acutely ill patients with weakness. It is not generally used in the home.. In Duchenne, mechanically (and manually) assisted coughing are the primary intervention to aid airway clearance.
- Should a 16yo be using a cough assist and BiPAP?
Age is not an indicator, but this person should have pulmonary function testing and, most likely, as sleep study to evaluate the need for cough assist and/or pulmonary assistance.
- We can see from DuchenneConnect that a significant number of patients ages 14-17yo have not had pulmonary function testing (PFT). Age what age should PFT’s start and how often should they be repeated?
PFT’s should start by age 6, or as soon as the patient can perform the testing. This testing should be repeated at least every 6-12 months. This test is essential for determining the pulmonary needs of the patient and is necessary for maintaining pulmonary health.
Other Webinars in This Series