What are the guidelines for PEFr (Peak Expiratory Flow Rate) based clearance for limb fracture surgery?

Guidelines for PEFR-Based Clearance for Limb Fracture Surgery

Peak Expiratory Flow Rate (PEFR) should be assessed prior to limb fracture surgery, with a value less than the patient's baseline indicating the need for clinical evaluation before proceeding with surgery. 1

Assessment of Respiratory Function for Surgical Clearance

PEFR Measurement Protocol

• PEFR should be recorded as the best of three forced expiratory blows immediately after a full inspiration with the patient either standing or sitting 1
• Use electronic peak flow meters when available to improve accuracy 1
• Compare current PEFR to the patient's baseline value when known

PEFR-Based Risk Stratification

1. Normal PEFR (≥ patient's baseline): Proceed with surgery if other clinical parameters are stable
2. Reduced PEFR (< patient's baseline): Evaluate clinical condition before administering anesthesia 1
3. Significantly reduced PEFR: Consider delaying surgery for optimization of respiratory status

Integration with Overall Surgical Risk Assessment

Respiratory Function in Trauma Risk Assessment

The guidelines for acute care of severe limb trauma patients include respiratory function as a key component in risk stratification 1:

• Stable respiratory function: PaO₂/FiO₂ > 300 - Low risk
• Moderate ARDS or hypoxemia: PaO₂/FiO₂ 150-300 - Intermediate risk
• Severe ARDS or hypoxemia: PaO₂/FiO₂ < 150 - High risk

Clinical Decision Algorithm

1. Low-risk patients: Early safe definitive orthopaedic surgery
2. Intermediate-risk patients: Initial resuscitation, temporary stabilization, and prompt individualized safe management (PRISM)
3. High-risk patients: Damage-control orthopaedics (mid-term stabilization) followed by safe delayed definitive orthopaedic surgery 1

Special Considerations

Asthma Patients

• For patients with asthma, a PEFR variability of ≥12% should be considered a positive test for active airway disease 1
• In patients receiving allergen immunotherapy, PEFR should be obtained before leaving the clinic with a predefined level marked on the PEFR chart to alert for rescue medication 1

Timing of Surgery Based on Respiratory Status

• In patients with severe preoperative respiratory compromise, the benefit-risk ratio between definitive osteosynthesis or external fixation should be the subject of multidisciplinary discussion 1
• For femoral shaft fractures with respiratory compromise, temporary stabilization (external fixator or osseous traction) may be necessary until respiratory status improves 1

Practical Implementation

Pre-operative Assessment

• Assess respiratory function as part of the overall evaluation of the patient's clinical status
• Document PEFR values and compare to baseline when available
• Consider PEFR in conjunction with other respiratory parameters (oxygen saturation, respiratory rate, clinical examination)

Common Pitfalls to Avoid

1. Relying solely on PEFR: Remember that PEFR and FEV1 measurements are not equivalent when expressed as percentage of predicted values. FEV1 may be as much as 35% lower or up to 15% higher than the PEFR for patients with obstructive lung diseases 2
2. Ignoring other clinical factors: PEFR should be considered alongside hemodynamic status, coagulation parameters, and associated injuries
3. Failing to reassess: Respiratory status can change rapidly in trauma patients; regular reassessment is essential

By following these guidelines for PEFR-based clearance, surgical teams can better stratify risk and optimize timing of limb fracture surgery to reduce perioperative complications and improve outcomes.