What is the rate of periprosthetic joint infections (PJI) associated with the use of Bair Hugger (forced-air warming blanket)?

Rate of Periprosthetic Joint Infection Associated with Bair Hugger Use

There is no specific rate of periprosthetic joint infections (PJI) directly attributable to Bair Hugger forced-air warming blankets established in current high-quality clinical guidelines or research.

Background on PJI Risk

Periprosthetic joint infection is a devastating complication of joint replacement surgery with significant implications:

• The prevalence of PJI is approximately 1.63% for hip replacements and 1.55% for knee replacements at 2 years post-surgery, with rates exceeding 2% at 10 years 1
• PJI significantly increases mortality risk, with one study showing a fivefold increase in mortality compared to aseptic revisions 2
• PJI is associated with decreased quality of life, increased morbidity, and potential for decreased mobility 1

Forced-Air Warming and PJI: The Evidence

The concern about Bair Hugger and similar forced-air warming (FAW) devices stems from theoretical concerns about disruption of laminar airflow in operating rooms:

• Some laboratory models suggest that forced-air warming may disrupt laminar flow and potentially increase bacterial load at the operation site 1
• However, this hypothesis has not been formally tested in adequately powered randomized controlled trials 1
• A systematic review examining this specific concern produced inconclusive results 1

Current Recommendations on Patient Warming

Despite concerns about forced-air warming, maintaining normothermia remains a strong recommendation:

• Multiple guidelines recommend maintaining normothermia throughout the perioperative period to reduce SSI risk 1
• Four randomized controlled trials and at least two meta-analyses confirm risk reduction through maintaining normothermia 1
• The 2020 AAOS guidelines on PJI prevention do not specifically contraindicate forced-air warming devices 1

Alternative Warming Methods

Several warming methods exist with comparable effectiveness:

• Forced-air warming (most widely studied and used)
• Resistive polymer fabric warming
• Circulatory warming systems using a closed fluid circuit 1
• A randomized controlled non-inferiority study comparing self-warming blankets to forced-air warming found only a 0.2°C difference between groups, which was not clinically significant 3

Risk Factors for PJI

Rather than focusing solely on warming devices, guidelines emphasize multiple risk factors for PJI:

• Poor glycemic control (target HbA1c <7.5%)
• Obesity (BMI >35)
• Malnutrition
• Smoking
• MRSA colonization 4

Clinical Implications

When considering the use of forced-air warming devices:

1. The primary goal should be maintaining normothermia, as hypothermia is a well-established risk factor for surgical site infections
2. In orthopedic implant surgery where concerns exist about laminar airflow disruption, consider alternative warming methods if available
3. Focus on established PJI prevention strategies including appropriate antibiotic prophylaxis, skin preparation, and optimization of modifiable patient risk factors

Conclusion

While theoretical concerns exist about forced-air warming devices potentially disrupting laminar airflow in orthopedic implant surgery, there is no established specific rate of PJI attributable to Bair Hugger use in current high-quality evidence. The decision to use forced-air warming should balance the well-established benefits of maintaining normothermia against theoretical concerns about airflow disruption.