Respiratory Complications in Spinal Cord Injury

After a motor boat accident paralyzed Kenny Cranmer from the shoulders down, his life changed physically, emotionally, and financially. The 22-year veteran racer who spent summers running boats off the coast of New Jersey can’t move or breathe without the support of a wheelchair and ventilator. “Although I try to keep a positive attitude, it is not easy,” Cranmer said.

Five months of intensive rehabilitation have helped him regain feeling in his left arm, shoulders, left foot, and buttocks. He has begun eating and drinking on his own and has had some success with ventilator weaning. But he and wife, Bonnie, must vigilantly guard against visitors and staff transmitting upper respiratory infections.

Complications such as pneumonia, pulmonary emboli, and septicemia are the leading killers of patients with spinal cord injury.1,2 That is why three model system centers funded by the National Institute on Disability and Rehabilitation Research to improve preventative care, management, and quality of life for the 265,000 people living with spinal cord injury are focusing on respiratory outcomes.1 Respiratory therapists are at the forefront of research into high ventilator tidal volumes, cough assist techniques, diaphragmatic pacing, and multidisciplinary-guided therapy.

Innovative programs

Decreased respiratory drive is the most immediate enemy of a spinal cord injury patient. “Most of these patients one second before their injury had perfectly normal lungs,” said Michael Feinberg, RRT, manager of respiratory therapy at Kessler Institute for Rehabilitation, a model system center in West Orange, N.J. “They don’t have the diaphragm motion now to push air in and out.” Without deep breaths, sighs, and coughs, lung secretions can pool in the temporal lobes of patients’ lungs, precipitating a cycle of infection and atelectasis.3

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Respiratory therapists at Craig Hospital in Englewood, Colo., are testing whether ventilator tidal volumes higher than those recommended by the ARDsNet protocol could better protect against lung collapse. A previous retrospective study of the medical records of 42 patients had shown that patients managed with larger tidal volumes were significantly less prone to atelectasis and weaned 21 days faster than the low-tidal volume group.

Craig Hospital’s five-year prospective, controlled study appears to support larger tidal volume’s role in reducing atelectasis. Thirty-four ventilator-dependent patients were randomized to receive a tidal volume of either 20 or 10 ml/kg of ideal body weight. “We didn’t see any differences in lung-health outcomes between the two patient populations,” said Lonnie Martinez, BS, RRT, director of respiratory care at Craig Hospital. They speculate that both populations did well because they were managed using higher tidal volumes.

Researchers at Thomas Jefferson University Hospital, a model center in Philadelphia, have specialized in studies of patient’s walking and upper extremity mobility, but their work has crossed over into respiratory as they explore methods to restore the body’s trunk, lower limb, and upper limb functionality and protect it from infection.

Gaining independence

Patients unable to wean from ventilators face impaired mobility and poor quality of life in the first months post-injury. Diaphragmatic pacing systems (DPS) have the potential to be a more portable and inconspicuous ventilatory option for a small subset of these patients. The device consists of four electrodes implanted on the phrenic nerve’s motor points in the diaphragm and an external generator that provides electrical stimulation to contract the diaphragm, which mimics natural breathing and fills the lungs with air using natural negative pressure. Candidates for the device must have an intact phrenic nerve. It also is suggested they have a good support system, are at least 18 years old, and cannot have/need a cardiac pacemaker or future MRI.

At Thomas Jefferson University Hospital, a protocol gives respiratory therapists a key role in working with patients post-surgery to wean them from positive pressure ventilation to DPS. Following the minimally invasive laproscopic surgery, RTs suction the patient’s airway to remove obstructions, connect the generator, and begin conditioning the patient’s diaphragm. They pace the diaphragm to fatigue then return the patient to conventional ventilation for at least 45 minutes, repeating as often as possible to help build the atrophied muscle’s strength. RTs also monitor patient vital signs and vital capacity, and provide support to patients breathing on their own, sometimes for the first time in years. “We try to give patients a lot of support the first time they come off the ventilator because they can be very anxious,” said Danielle Goodwin Kaprielyan, BS, RRT, who wrote the protocol and works in the neuro intensive care unit at Thomas Jefferson University Hospital’s respiratory care department.

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Diaphragmatic Pacing System Protocol

Download the protocol used by respiratory therapists at Thomas Jefferson University Hospital in Philadelphia.

Patients initially can only breathe for a few minutes on DPS, but some are completely independent of the ventilator within two weeks of the surgery. “Depending on the patients needs, we are able to adjust the protocol accordingly,” said Kaprielyan. The effectiveness of this device has not been validated by a large scale clinical trial, but anecdotal evidence from Kaprielyan’s facility suggests that patients on this device do not develop pneumonia. Patients also report greater mobility, sense of smell, appetite, and confidence in their appearance.

Multidisciplinary approach

Building muscle strength to do transfers and learning how to prevent respiratory infections is the next step for patients as they prepare to be discharged home. In a unique program at Kessler Institute for Rehabilitation, physical, occupational, and speech therapists work with patients in the gym for 15 hours a week. There, they focus on stretching and strengthening patients’ trunk and upper extremity muscles and increasing tolerance to upright to help improve respiration and functional mobility. They facilitate postural drainage with the use of tilt tables as well as positioning in the wheelchair and on the mat. Physical therapists also use mirror exercises to help them visualize whether they’re using their diaphragm for breathing exercises or less energy-efficient accessory muscles that tire more easily.

“These can be tough patients because there are so many tubes and it can be hard to move them around,” said Barbara Garrett, PT, senior physical therapist. To ensure they are safe in the gym environment, nurses and physical, occupational, and speech therapists at Kessler Institute for Rehabilitation are certified annually in ventilator proficiency. Each practitioner is trained on ventilator and in-exsufflator troubleshooting, airway secretion removal, and emergency management. Nurses receive a more intensive three days of classroom and hands-on learning about ventilator care and respiratory physiology. Everyone must demonstrate proficiency before they work with patients.

“It is really important for all disciplines to have a working knowledge of the patient,” said Feinberg, manager of respiratory therapy. “With spinal cord injury, the higher their injury, the less reserve they have. If there is something wrong with the ventilator, they are not breathing. We don’t have that much time to spare.”

Going home

After patients discharge home, they must protect against community-acquired pneumonia and respiratory infections that cause frequent rehospitalizations. Respiratory therapists, physicians, and research scientists at Kessler Institute for Rehabilitation are studying whether manual and mechanical assisted cough techniques or incentive spirometry better avert respiratory infections requiring antibiotics and lung collapse.

Researchers tracked the lung function of 120 SCI patients with ineffective cough for three years. At six, 12, 24, and 36 months, patients performed vital capacity, peak cough flow, and maximum insufflation capacity. Under analysis is whether patients using cough assist devices are hospitalized less frequently with atelectasis or respiratory infection requiring antibiotics than those who use incentive spirometry.

More than 26,000 people currently are enrolled in a database shared by the model spinal cord injury centers, with more joining every year. Ongoing studies are aimed at helping them manage respiratory health outcomes and improve their quality of life. For example, researchers at Case Western Research University in Cleveland, Ohio are testing whether electrical stimulation of patients’ spinal cords can produce an effective cough.5 Other specialty centers are assessing how sleep disordered breathing, which affects 83 percent of tetraplegics, influences other comorbidities, mood, and quality of life.6 And eight centers, led by Craig Hospital, are starting a five-year study to isolate the specific rehabilitation interventions most valuable for long-term survival.7

“Our responsibility is to prepare the patient to go out and have a productive life that is meaningful even though they are paralyzed,” summarized Martinez. Craig Hospital and its model center partners, he says, are just “a dress rehearsal for the rest of the patient’s life.”

View a list of references at advanceweb.com/respiratory.

Contact Kristen Ziegler at [email protected].