What is the impact of backboards on the respiratory system, particularly in patients with pre-existing conditions like Chronic Obstructive Pulmonary Disease (COPD) or asthma?

Impact of Backboards on the Respiratory System

Backboards cause significant respiratory compromise by restricting lung function approximately 15% on average, with more pronounced effects in patients at extremes of age and those with obesity, making their use particularly concerning in patients with pre-existing respiratory conditions like COPD or asthma. 1

Respiratory Mechanics and Functional Impact

Direct Pulmonary Function Impairment

Spinal immobilization with backboards and cervical collars produces measurable respiratory restriction:

• Both hard wooden backboards and vacuum mattresses reduce respiratory function by approximately 15% compared to baseline measurements 1
• Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) decline significantly following spinal immobilization 2
• In obese volunteers with android-type obesity, pulmonary functions decline significantly at both 0 minutes and 30 minutes of immobilization, with no difference between 0-degree and 20-degree positioning 2
• The respiratory restriction is more pronounced at the extremes of age, making elderly patients and children particularly vulnerable 1

Mechanism of Respiratory Compromise

The backboard restricts chest wall expansion and diaphragmatic excursion:

• Positive-pressure ventilation increases intrathoracic pressure and may reduce venous return and cardiac output, especially in patients with obstructive airway disease 3
• Devices applied to secure airways should avoid compression of the front and sides of the neck, which may impair venous return from the brain 3
• The supine position on a rigid surface limits the natural mechanics of breathing, particularly affecting tidal volume 1

Special Considerations for COPD and Asthma Patients

Heightened Vulnerability in Obstructive Lung Disease

Patients with COPD or asthma face compounded respiratory challenges when placed on backboards:

• COPD patients already experience increased mechanical workload with greater energy consumption of inspiratory muscles at any given level of minute ventilation 3
• During acute exacerbations, airway resistance and end-expiratory lung volume increase substantially, and the breathing pattern becomes abnormal with decreased tidal volume 3
• The esophageal detector device may yield misleading results in patients with status asthmaticus because the trachea tends to collapse in the presence of this condition 3
• Patients with obstructive airway disease are particularly susceptible to reduced cardiac output from increased intrathoracic pressure 3

Clinical Implications During Transport

The combination of backboard-induced restriction and underlying disease creates a dangerous scenario:

• Backboards present known risks including respiratory compromise, pain, and pressure sores, and their value in protecting the spinal cord remains unsubstantiated 4
• Backboards should only be used judiciously given these documented risks 4
• During cardiac arrest resuscitation, backboards and commercial devices provide equivalent methods for preventing inadvertent tube displacement and may be considered during patient transport 3
• The 2022 International Consensus suggests either a backboard or no-backboard strategy for chest compression depth during in-hospital cardiac arrest, acknowledging equipoise 3

Practical Management Recommendations

Risk Mitigation Strategies

When backboard use is deemed necessary in patients with respiratory disease:

• Minimize time on the backboard - use only during extrication and immediate transport, then transition to alternative immobilization methods 4
• Consider vacuum mattresses as an alternative, which are significantly more comfortable though they produce similar respiratory restriction 1
• Monitor respiratory status continuously, particularly in patients with known COPD or asthma 3
• Be prepared for acute decompensation, especially in patients with severe obstructive disease who have limited respiratory reserve 3

Common Pitfalls to Avoid

• Do not assume backboards are benign - they cause measurable harm including respiratory compromise that is particularly dangerous in patients with pre-existing lung disease 4, 1
• Avoid prolonged immobilization beyond what is absolutely necessary for spinal protection during extrication 4
• Do not overlook the cumulative effect of cervical collar plus backboard, as both contribute to respiratory restriction 1
• In obese patients, recognize that even 20-degree elevation does not mitigate the respiratory compromise compared to traditional 0-degree positioning 2