Respiratory Management in Spinal Cord Injury

Original Editor - Eugenie Lamprecht

Top Contributors - Eugenie Lamprecht, Naomi O'Reilly and Kim Jackson  

Introduction

Respiratory dysfunction is one of the most common medical complications, as well as the leading cause in reduced Quality of Life (QoL) and mortality among individuals with Spinal Cord Injuries.[1][2][3] The spinal cord injury level and whether or not the spinal cord injury is complete or incomplete is directly associated with the extent of the respiratory dysfunction. A universal classification tool used to assess the level and the completeness is known as the American Spinal Injury Association (ASIA) Scale. Cervical and higher thoracic spinal cord injury are more prevalent to develop respiratory complications. [1] This is due to the diaphragm impairment. The diaphragm is accountable for 65% of forced vital capacity and therefore plays a large role in ventilation.[3] Literature indicates that 67% of individuals with a spinal cord injury, present with respiratory complications in the acute stage, of which higher cervical spinal cord injury are far more common.[4]


Pathophysiology

In order to understand how respiratory functioning is affected among individuals with a spinal cord injury, it is important to understand how normal ventilation occurs. The video below explains the mechanisms of breathing in healthy individuals;

[5]

Spinal cord injury involves the innervation of the diaphragm, intercostal muscles and the abdominal muscles directly affects the mechanics of breathing. The following table illustrates the level of neurological injury relevant to impairment;[1][2]

Neurological level Impairment
C1-3 Full Ventilator Dependent
C3-4 Periods of Unassisted Ventilation

Diaphragm Impaired - ↓ Tidal Volume & Vital Capacity

C5 Independent Ventilation

Initial Ventilatory Support

Diaphragm Intact

Intercostals and Abdominal Muscles Impaired - ↓ Lung Volumes and Forced Expiration for effective secretion clearance

C6-8 Independent Ventilation

Diaphragm Intact

Intercostals and Abdominal Muscles Impaired - ↓ Lung Volumes and Forced Expiration for effective secretion clearance

Uses Accessory Muscles to generate an effective cough

T1-4 Independent Ventilation

Diaphragm Intact

Intercostals Intact - Normal Lung Volumes

Abdominal Muscles Impaired - ↓ Forced Expiration for effective secretion clearance

T5-12 Ventilation near equal or equal to individuals without spinal cord injury

[2]

Another common complication that occurs among acute quadriplegia is excessive bronchial mucus production. The cause of this is still uncertain but is thought to be due to reduced vagal nerve activity, which leads to a parasympathetic imbalance that causes;

  • Bronchial Spasm
  • Increased Vascular Congestion, and
  • Decreased Mucociliary Activity (related to mechanical ventilation)[1]

After the hpinal ock phase, abnormal spinal reflexes may lead to spastic contraction of abdominal muscles. This increases the work of breathing in these individuals and may lead to dyspnea[1].

It is also important to know that erect positions negatively affects ventilation due to a flattened diaphragm and the forward movement of abdominal content, which is related to impaired breathing mechanisms. It is therefore important to consider abdominal binders etc to assist with breathing in erect positions.[1]

Possible Complications

  1. Hypoventilation,
  2. Reduced Surfactant Production,
  3. Mucus Plugging,
  4. Atelectasis,
  5. Pneumonia
  6. Pulmonary Oedema
  7. Pulmonary Embolism
  8. Sleep-Disordered Breathing and Sleep Apnoea Syndrome [1][2]

Medical Management

The standard medical practice involves early surgical stabilisation of the spine and close monitoring in intensive-care units.[1][2]

Monitoring

The entire multidisciplinary team is responsible for monitoring the;

  • Diaphragmatic Function
  • Pulse Oximetry
  • Arterial gasometry

Markers that indicate the need for intubation are;

  • VC below 15mL/kg
  • Maximum Inspiratory Pressure below -20cmH2O
  • Increased pCO2[2]

Ventilation, Weaning and Extubation

Intubation is important when individuals require ventilatory support, which is in 100% of cases with complete C5 and above SCIs. Different ventilation methods and settings are used to the specific respiratory needs of each individual.

Evidence supporting the optimal weaning protocols are limited. However, literature indicates a regime of starting with bidaily trails, 3 to 4 hours rest in between and progressing onwards. Progressive Ventilator-Free Breathing (PVFB), T-tube with Pressure Support (PS), and Synchronised Intermittent Mandatory Ventilation (SIMV) are the most common methods used of weaning. It's important to note however those individuals on SIMV generally take longer to wean successfully.

The decision to extubate has to be made by the entire multidisciplinary team, while close monitoring and chest physiotherapy should follow. Requirements before extubation include;

  1. No surgical or diagnostic procedures on the day of extubation
  2. No Sedation
  3. Stable Vital Signs as arterial gas levels
  4. Normal Fluid Balances
  5. O2 SATS > 95%, pCO2 < 40-45mmHg
  6. FiO2 < 25%, PEEP < 5cmH2O
  7. Inspiratory Pressure < -20cmH2O
  8. VC > 10-15mL/kg of ideal body weight
  9. Normal Chest X-rays
  10. Few Secretions
  11. No Contra-indications for Chest Physiotherapy Intervention[1]

Tracheostomy and Decannulation

Reasons for tracheostomy include;

  • Relieve Upper-Airway Obstruction,
  • Prevent Upper-Airway Damage
  • Enable frequent Suctioning
  • Enables Long-term Ventilatory Support.

Benefits include;

  • Patient Comfort,
  • Reduced Work of Breathing,
  • Improved Safety,
  • Improved Oral Hygiene,
  • Accelerated Weaning and
  • Lower Risk of Ventilator-Associated Pneumonia.[6]

Many individuals with SCI who develop respiratory complications or have a high level complete spinal cord injury are likely to receive a tracheostomy. When decannulation is considered it is important for the entire multidisciplinary team to assess the airway patency, cough and swallowing effectiveness as well as oxygen requirements, medical stability, patient co-operation, oxygen dependence and infection markers[1][2].

Physiotherapy Management

Secretion Clearance Techniques

Assisted Coughing Techniques

A synchronized inward and upward manual force under the diaphragm or compression of the rib cage, in order to create intra-abdominal pressure for an effective forceful cough. Ultimately the physiotherapist's manual force will facilitate the intercostal and abdominal muscles to increase the intra-abdominal pressure necessary for an effective cough.[1][2]

[7]

Postural Drainage

This will allow gravity to assist the movement of secretions towards the upper airway for removal via coughing or suctioning. Duration of postural drainage can vary from 5 to 10 minutes. [1]

Postural drainage.jpg

Percussions and Vibrations

Percussions and vibrations are used as a manual technique by physiotherapists in order to loosen secretions by causing vibrations in the chest wall. Important precautions and contraindications need to be taken into account prior to execution.

Contraindications include;

  • Cardiovascular Instability
  • Tension pneumothorax
  • Active Pulmonary Tuberculosis (TB)
  • Pulmonary Embolism (PE)
  • Severe Pleural Effusion
  • Unstable Spinal and / or Cranial Fractures
  • Fractured Ribs
  • Chest Wounds
  • Acute Haemoptysis
  • Increased Intracranial Pressure (ICP)[1]
[8]

Breath Stacking

Two or more inspiratory breaths before exhalation. This technique can be conduction by the individual actively performing breath stacking (respiratory sniff or inspiratory hold techniques) as well as through using a resuscitation bag with a mouthpiece or facemask.[2]

Improve Ventilation

Respiratory Muscle Training

Respiratory Muscle Training involves one-way valves to target either inspiratory or expiratory muscles.[9]. An example is spirometry training.

Non-Invasive Ventilatory (NIV) Support

This technique applies positive pressure in the airways and is known as positive-pressure support. Examples of positive-pressure support devices are; CPAP, BPAP and IPPB. Individuals should be cooperative and the preferred technique should be conducted during day time via a mouthpiece and at night time, via a nosepiece. NIV support are also known to be used for initial ventilatory support or weaning and as night support.

[10]

Mobilization

Mobilization is also an effective technique in secretion clearance and improving ventilation. Physiotherapists can assist individuals with a spinal cord injury to sit out in a chair once the spinal fractures are surgically stabilised. Early mobilisation has proven to accelerate recovery and reduce hospital stay. It is however extremely important for physiotherapists to consider using abdominal binders and slow progressive elevation during the spinal shock phase, as an individual with spinal cord injury may struggle with hypotension and increased work of breathing in the upright position. Antihypotensive medication can also be administered by the medical team if indicated.[2]

Long-Term Ventilation

Individuals with a spinal cord injury of C4 and higher often require long-term ventilatory support. Caregiver education and extensive training must be conducted by the entire multidisciplinary team. Frequent medical and physiotherapy assessments are advised in order to monitor the individual's condition.

Conclusion

Respiratory management is often neglected in the management process of individuals with spinal cord injuries. Physiotherapists are most often primarily responsible for the respiratory management of individuals with a spinal cord injury. Therefore, it is essential for the physiotherapists to ensure they have the necessary knowledge and treatment techniques in order to do so effectively. We are also responsible to educate and inform other healthcare workers if necessary.

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Galeiras Vázquez R, Rascado Sedes P, Mourelo Fariña M, Montoto Marqués A, Ferreiro Velasco ME. Respiratory management in the patient with spinal cord injury. BioMed research international. 2013;2013.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Berlowitz DJ, Wadsworth B, Ross J. Respiratory problems and management in people with spinal cord injury. Breathe. 2016 Dec 1;12(4):328-40.
  3. 3.0 3.1 Zakrasek EC, Nielson JL, Kosarchuk JJ, Crew JD, Ferguson AR, McKenna SL. Pulmonary outcomes following specialized respiratory management for acute cervical spinal cord injury: a retrospective analysis. Spinal cord. 2017 Jun;55(6):559-65.
  4. Hagen EM. Acute complications of spinal cord injuries. World journal of orthopedics. 2015 Jan 18;6(1):17.
  5. Armando Hasudungan. Mechanism of Breathing. Available from: https://www.youtube.com/watch?v=GD-HPx_ZG8I [last accessed 3/9/2020]
  6. Durbin CG. Tracheostomy: why, when, and how?. Respiratory care. 2010 Aug 1;55(8):1056-68.
  7. SpinalHub. How to assist cough a person with spinal cord injury. Available from: https://www.youtube.com/watch?v=lp-LBgD5Y5M [last accessed 3/10/2020]
  8. Jack Thompson. Percussion, vibration and shaking for clearing secretions. Available from: https://www.youtube.com/watch?v=qr-FJ3RdGuQ [last accessed 3/10/2020]
  9. Tamplin J, Berlowitz DJ. A systematic review and meta-analysis of the effects of respiratory muscle training on pulmonary function in tetraplegia. Spinal Cord. 2014 Mar;52(3):175-80.
  10. Jimmy McKanna - RT Clinic. RT Clinic : CPAP vs. BiPAP What is the difference. Available from: https://www.youtube.com/watch?v=jmQ-B40_8NU [last accessed 3/10/2020]